@INPROCEEDINGS{0509:Implementation, AUTHOR="Xi Zhang and Patrick Svedman", TITLE="Implementation of a Smart Antenna Multiuser Algorithm on a {DSP-Based} Wireless {MIMO} {Test-Bed}", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="This paper describes the implementation and performance of three communication schemes on a DSP-based MIMO test-bed. A multicell scenario with two basestations and two users in the same room is evaluated. Eigenbeamforming with and without interference pre-whitening at both transmitter and receiver is compared with SISO multicell communication. Experimental results show that the gain from using interference pre-whitening is significant. The BER performance of beamforming without intercell interference suppression is only marginally better than single antenna communication. The paper also presents the implementation of synchronization, equalization, frequency offset estimation and decision directed beamforming mismatch compensation." } @INPROCEEDINGS{Aalo0504:Average, AUTHOR="Valentine Aalo and Terawat Piboongungon and George Efthymoglou", TITLE="Average Error Rates for Equal Gain Combining Schemes in Nakagami Fading Channels with Arbitrary Fading Parameters", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="Equal gain combining (EGC) is employed in many practical wireless communication systems to combat fading and interference due to its simplicity. However, although EGC is easy to implement, its performance is usually very difficult to evaluate. This difficulty stems from the fact that it is usually not easy to express the probability density function (pdf) of the sum of independent Nakagami-m distributed random variables in closed-form. In this paper, we derive an expression for the pdf of the sum of independent Nakagami random variables in terms of multivariate hypergeometric function. Consequently, we express the average error rate of several digital modulation schemes at the output of the EGC in terms of the well known multivariate Lauricella function." } @INPROCEEDINGS{Aalo0511:Multivariate, AUTHOR="Valentine Aalo and Terawat Piboongungon", TITLE="On the Multivariate Generalized Gamma Distribution with Exponential Correlation", BOOKTITLE="Globecom 2005 Communication Theory", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="In this paper, we study the multivariate generalized gamma distribution with exponential correlation with identical fading parameters. Expressions for the joint distribution and the joint central moments are derived. Using the derived expressions, the outage probability for multi-branch selection combining receiver over a correlated generalized gamma fading channels is obtained." } @INPROCEEDINGS{Abba0505:Comparative, AUTHOR="Taemoor Abbasi and Shekhar Prasad and Nabil Seddigh and Ioannis Lambadaris", TITLE="A Comparative Study of the {SIP} and {IAX} {VoIP} Protocols", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Recently, there has been a strong focus on the development of scalable Voice over IP (VoIP) protocols which are suitable for wide scale deployment. SIP (Session Initiation Protocol) is one such protocol which has been the subject of extensive research over the past few years. More recently, IAX (InterAsterisk Exchange Protocol) has emerged as a new VoIP protocol which is steadily gaining credence among the open source community. Among the benefits claimed by the proponents of IAX are its simplicity, NAT-friendliness, efficiency and robustness. This paper makes three key contributions to VoIP research. Firstly, we undertake a comparative evaluation and analysis of the SIP and IAX protocols. Secondly, we report on the viability of utilizing the Asterisk PBX as a foundation for conducting research performance studies for VoIP. Finally, we report on live experimental studies of SIP and IAX voice traffic in the Ottawa Metropolitan area. We experimentally studied the performance of voice calls initiated using SIP and IAX for a variety of delay and loss characteristics. In addition, we examined the performance of both protocols in the presence of packet reordering. Our preliminary observations demonstrate that the IAX protocol compares favourably in relation to SIP. More detailed studies are required to evaluate the performance of IAX-based voice traffic in large-scale deployment." } @INPROCEEDINGS{Abba0506:Analytical, AUTHOR="Ash Mohammad Abbas", TITLE="An Analytical Framework for Disjoint Multipath Routing in Mobile Ad hoc Networks", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="An ad hoc network is a collection of mobile nodes connected through multihop wireless links without the required intervention of any centralized access point or an existing infrastructure. Design of disjoint multipath routing protocols is a challenging task in an ad hoc environment. In this paper, we have described an analytical framework for disjoint multipath routing in mobile ad hoc networks. The main parameters analyzed are probability of finding disjoint paths, routing overheads due to mobility and probability of disjoint path diminution." } @INPROCEEDINGS{Abd-0505:Wireless, AUTHOR="Mostafa Abd-El-Barr", TITLE="Wireless Sensor Networks - Part {I:Topology} and Design Issues", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Wireless Sensor Networks Part I: Topology and Design Issues Mostafa Abd-El-Barr Information Science Department Kuwait University mostafa(at)cfw.kuniv.edu Mohamed A. M. Youssef Information Science Department Kuwait University myoussef(at)ieee.org Mariam Al-Otaibi Information Science Department Kuwait University malotaibi(at)yahoo.com ABSTRACT Wireless sensor networks (WSNs) have a wide range of invaluable civil and military applications. A typical WSN consists of a distributed collection of sensor nodes interconnected by wireless links. Each node has one or more sensors, an embedded processor, and low-power radios. Nodes act as information sources, sensing and collecting data samples from their environment. They perform routing functions, creating multi-hop wireless networking fabric that conveys data samples to other sensor nodes. Nodes can also act as information sinks, receiving dynamic configuration information from other nodes or external entities. A number of important performance measures have to be considered in designing WSN. Among these, energy efficiency and adaptive medium access control (MAC) protocol represent the most crucial ones. Sensor nodes are battery powered, and it is often very difficult to change or recharge batteries for these nodes. Prolonging network lifetime for these nodes is therefore a critical issue. Another important attribute is scalability. This is needed in order to respond to the changes in network size, node density, and topology. Some nodes may die over time; some new nodes may join later; and some nodes may even move to different locations. Adaptive MAC protocols are needed to accommodate WSNS dynamics. In Part I of this series, we review a number of topologies and design techniques used in the deployment of WSNs. In particular, we cover the star, mesh and hybrid topologies and relate them to different military and civil applications. A number of factors influencing the design of WSNs, such as power, scalability, operating environment, transmission media, fault tolerance, and topology changes are discussed. We also present a number of WSNs communication architectures. We end our coverage with a discussion on recent advancement of algorithms used in WSNs. We focus on algorithms used in sensor deployment and coverage. SUBJECT AREA OF PREFERENCES (3) Communications and Wireless Systems CONTACT PERSON Mostafa Abd-El-Barr Professor and Head Information Science Department Kuwait University P. O. Box: 5969, Safat 13060, Kuwait Udaylia Campus, Admin. Bldg., Room 20 Fax: (965) 251-4252 Email: mostafa(at)cfw.kuniv.edu" } @INPROCEEDINGS{Abd-0505:Wireless, AUTHOR="Mostafa Abd-El-Barr", TITLE="Wireless Sensor {Networks-Part} {II:} Routing and Security Issues", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Wireless Sensor Networks Part II: Routing and Security Issues Mostafa Abd-El-Barr Information Science Department Kuwait University mostafa(at)cfw.kuniv.edu Maryam Al-Otaibi Information Science Department Kuwait University malotaibi(at)yahoo.com Mohamed A. M. Youssef Information Science Department Kuwait University myoussef(at)ieee.org ABSTRACT Wireless sensor networks (WSNs) have a wide range of invaluable civil and military applications. A typical WSN consists of a distributed collection of sensor nodes interconnected by wireless links. Each node has one or more sensors, an embedded processor, and low-power radios. Nodes act as information sources, sensing and collecting data samples from their environment. They perform routing functions, creating multi-hop wireless networking fabric that conveys data samples to other sensor nodes. Nodes can also act as information sinks, receiving dynamic configuration information from other nodes or external entities. A number of important performance measures have to be considered in designing WSN. Among these, energy efficiency and adaptive medium access control (MAC) protocol represent the most crucial ones. Sensor nodes are battery powered, and it is often very difficult to change or recharge batteries for these nodes. Prolonging network lifetime for these nodes is therefore a critical issue. Another important attribute is scalability. This is needed in order to respond to the changes in network size, node density, and topology. Some nodes may die over time; some new nodes may join later; and some nodes may even move to different locations. Adaptive MAC protocols are needed to accommodate WSNS dynamics. In Part II of this series, we present a review of different routing techniques and security issues. We present two possible routing classifications techniques. The first is based on Operation Models. Examples include Low Energy clustering Hierarchy (LEACH), Power Efficient Gathering in Sensor Information Systems (PEGASIS), Sensor Protocols for Information via Negotiation (SPIN), and Geographical and Energy-Aware Routing (GEAR). The second technique is based on Network Structure and Protocol Operation. Examples include Flat Network (FNR), Hierarchical Network (HNR), Location Network (LNR), Multi-Path Network (MNR), Quality of Service Network (QoSNR), and Coherent Network (CNR). A comparison among different routing techniques is provided. Security issues are the last topic discussed in Part II. SUBJECT AREA OF PREFERENCES (3) Communications and Wireless Systems CONTACT PERSON Mostafa Abd-El-Barr Professor and Head Department of Information Science Kuwait University P. O. Box: 5969, Safat 13060, Kuwait Udaylia Campus, Admin Bldg., Room 20 Fax: (965) 251-4252 Email: mostafa(at)cfw.kuniv.edu" } @INPROCEEDINGS{Abde0504:Effect, AUTHOR="Mohammed Abdel-Hafez", TITLE="Effect of Pulse Selection on the Capacity of {Multi-User} {UWB} Systems", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="This paper investigates the channel capacity with respect to pulse waveform of M-ary pulse position modulation (PPM) ultra wideband (UWB) communication systems over additive white Gaussian noise channel (AWGN). Based on Gaussian approximation for the multiple access interference, an expression of the signal-to-noise ratio is derived for the UWB system using various forms of pulses. In addition to rectangular pulse, Gaussian, 1st and 2nd derivative Gaussian, Laplacian, Exponential, and Hermite pulse waveforms are studied. The effect of pulse selection on the UWB capacity is investigated in AWGN multiuser channel. Analytical and simulation results show that the capacity of UWB system is highly influenced by the selected pulse shape." } @INPROCEEDINGS{Abde0504:Stability, AUTHOR="Yousry Abdel-Hamid and T. Aaron Gulliver", TITLE="On the Stability of the Random Waypoint Model for Ad hoc Networks", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="Mobile communications is an important research area. Much attention has currently been focused on the performance evaluation of wireless communication techniques, especially data communications, where access to the Internet is the most important application. By far the most widely used model for wireless ad-hoc networks is the Random Waypoint (RWP) model. Simulation is the main technique used to design robust and reliable systems; therefore accurately modeling of mobile systems is critical. In an ad hoc network, the movement of nodes, their direction, speed and rate of change are important parameters that should be accurately measured in order to obtain reliable results. Most performance evaluations are obtained with the aid of various network simulation packages. In order to set up a proper simulation environment, a proper mobility model must be employed with accurate metrics in order to provide reliable results. Yoon, Liu and Noble provided an accurate examination of the RWP model. They showed that the most important parameter to gauge the stability performance in a mobile network is the system average nodal speed. Using the ns-2 network simulator, their study showed that the model fails to provide the desired steady state performance as a result of the sharp decay in nodal velocity over time, and hence ns-2 is not an ideal simulation tool. Our work has achieved two main tasks. First, we used OPNET as an alternative simulation platform to show that the modified model suggested by Yoon et al. provides much more accurate performance results, and that varying the maximum speed or running very long simulations is not the best solution. This is mainly due to very slow nodes that become entangled in low speed values and therefore do not reach their destinations until a very long period of time has passed. We have confirmed using OPNET that adopting a non-zero positive lower speed solves this problem, and significantly improves system stability. Consequently, much more accurate performance metrics and average system mobility can be obtained. In addition, we considered non-zero pause times for the nodes and studied how this affects the performance at different minimal speeds. OPNET was also used to study the effects of varying the minimal speed on the average system mobility. To achieve this, we introduced a new parameter called mobility ratio, which is simply the percentage of mobiles to paused nodes at any time instant. To maintain consistency, we used the same pause times and the same simulation durations as previously to examine the system response with respect to average mobility. We found that increasing the minimal speed affects the overall system average mobility, thus solving the decay velocity problem. This not only improves system stability, but also preserves the system mobility model, which in turn allows for a more accurate study of the system performance." } @INPROCEEDINGS{Abde0505:Robust, AUTHOR="Ayman Abdel-Samad and Alex Gershman", TITLE="Robust Transmit {Eigen-Beamforming} Based on Imperfect Channel Correlations", BOOKTITLE="ICC 2005 Wireless Communications", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="Transmit beamforming is a powerful approach to enhance the performance of wireless communication systems employing multiple antennas at the transmitter. Transmit beamforming based on channel covariance information has been pursued based on various criteria. A major drawback of existing techniques is that most of them require nearly perfect knowledge of the channel covariance matrix at the transmitter, which is not necessarily possible in practice. In this paper, we propose a more robust framework in which we take this issue into account and design a robust transmit beamformer to have the best performance under the worst-case mismatch. We show that, for a small mismatch, eigen-beamforming along the eigenvectors of the presumed channel correlation matrix offers the best worst-case performance among all other beamformers. We combine eigen-beamforming with robust power loading which is achieved by spatial water-filling-type strategy in which the water level is determined in a closed form." } @INPROCEEDINGS{Abde0509:Low, AUTHOR="Ayman Abdel-Samad", TITLE="{Low-Complexity} Iterative Frame Synchronization", BOOKTITLE="ISWCS 2005 Main Symposium", ADDRESS="Siena, Italy", DAYS=5, MONTH=sep, YEAR=2005, ABSTRACT="Iterative receiver techniques provide a powerful tool to enhance receiver performance and are gradually becoming the norm in modern communication systems. Although they have been used in various receiver components like channel estimation, equalization and decoding, they have not been explicitly applied to frame synchronization. In this paper, we propose a low-complexity iterative frame-synchronization technique in which the hard-output, un-coded data at the output of the equalizer is utilized to improve the accuracy of synchronization. Simulation results show huge signal-to-noise-ratio (SNR) gains in terms of false acquisition probability (FAP), mean square channel estimation error (MSCEE) and un-coded bit error rate (BER) at all SNR values. The proposed approach can be easily applied to continuous or burst type frame synchronization under additive white Gaussian noise (AWGN) in addition to flat or frequency-selective channels." } @INPROCEEDINGS{Abde0509:New, AUTHOR="Shawki Abdelkader and Christian Pietsch and Juergen Lindner", TITLE="Receive signal processing for space-time coded transmissions in the presence of channel estimation errors", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="The paper deals with space-time-coded transmissions in the presence of channel estimation errors. A simple transmission model is described which gives insight into the basic relations between space-time block coding schemes and the general concept of spreading. On the basis of this model, diagonal algebraic space-time (DAST) block codes are taken as an example. For maximum ratio combing and equal gain combining it is shown, that in case of channel estimation errors suboptimum algorithms at the receiving side might outperform optimum ones. The mathematical equivalence between DAST and multicarrier code division multiplexing as a by-product of the modelling is also discussed." } @INPROCEEDINGS{Abdo0505:Prediction, AUTHOR="Seyed Ehsan Abdollahi and Mehran Mirzayee", TITLE="Electromagnetic Field Calculation in an Axial Flux Solid Rotor Induction Motor", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="The induction machine with an axial air gap and a flat disk rotor shows some performance characteristics that are superior to conventional induction machines. Large rotational speeds and small moments of inertia promise high power densities and small mechanical time constants. In this paper an approximate 2D finite element method for the electromagnetic field calculation and performance analysis of a disk induction machine is presented. Experimental results and basic formulation are reported as well. The speed-torque characteristics obtained from theory are compared with those obtained experimentally and show acceptable results." } @INPROCEEDINGS{Abdo0505:Programmable, AUTHOR="Ahmad Abdo and Trevor Hall", TITLE="Programmable Traffic Generator with Configurable Stochastic Distributions", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="A FPGA-based reprogrammable traffic generator is described in this paper. A traffic generator could be used as a module in a test-bed facility for performance benchmarking of layer 2 (e.g. switch) or layer 3 (e.g. router) switching components. It is used as an alternative solution to recording real traffic which is an expensive task, since it requires extensive storage memory. Many implementations of traffic generators with different distributions were done in software, but these generators are slow and not suitable for high-speed hardware testing. We developed a hardware based traffic generator using a dedicated soft microprocessor within a configurable device. The architecture consists of an embedded NIOS processor implemented on a Stratix FPGA chip provided by Altera with additional hardware module programmed onto the same FPGA. The communication between on-chip modules will be realized by means of a shared data bus (Avalon Bus) embedded into the FPGA. The processor is to perform procedural calculations, communicate with the user interface and send control information to the Configurable Traffic Generator (CTG), in order to determine which generated data distribution. CTG is programmed at RTL level of abstraction using VHDL. The different modules were tested at a bit rate of 50 Mbps, although the architecture is scalable up to 2.5 Gbps (oc-48) when upgrading our development board to Stratix GX. A custom Application Program was programmed in Java, in order to provide a friendly user interface. The generated traffic consists of fixed length packets of 512 bits and can be one of the following three stochastic patterns: Self Similar, Markov Modulated Poisson Process and Markov Modulated Bernoulli Process; all the parameters of the mentioned distributions are specified by the user through a RS-232 connection with a local computer. The advantages of our design are numerous: scalability to different bit rate and being a low cost solution for testing switching equipments." } @INPROCEEDINGS{Abdo0506:Efficient, AUTHOR="Afshin Abdollahi and Massoud Pedram", TITLE="Efficient Synthesis of Quantum Logic Circuits by Rotation-based Quantum Operators and Unitary Functional Bi-decomposition", BOOKTITLE="International Workshop on Logic and Synthesis 2005", DAYS=8, MONTH=jun, YEAR=2005, ABSTRACT="Quantum information processing technology is in its pioneering stage and no efficient method for synthesizing quantum circuits has been introduced so far. This paper introduces an efficient analysis and synthesis framework for quantum logic circuits. The proposed synthesis algorithm and flow can generate a quantum circuit using the most basic quantum operators, i.e., the rotation and controlled-rotation primitives. We will introduce the notion of quantum factored forms, and develop a canonical and concise representation of quantum logic circuits in the form of quantum decision diagrams (QDDs) which are amenable to efficient manipulation and optimization including recursive unitary functional bi-decomposition. This representation will produce a rigorous graph-based framework for the analysis and synthesis of quantum logic circuits. Subsequently, an effective QDD-based algorithm will be developed and applied to automatic synthesis of quantum logic circuits." } @INPROCEEDINGS{Abdu0505:Scalability, AUTHOR="Abu Nasser {Mohammed Abdullah} and Haja Moinudeen and Wajdi Al-Khateeb", TITLE="Scalability and Performance Analysis of {IEEE} 802.11a", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT={Wireless LAN (WLAN) [3] has become the most talked about technology in last decade. Using Radio Frequency (RF) technology, WLANs transmit and receive data over the air, through walls, ceilings and even cement structures, without wired cabling. The IEEE 802.11 [4] specification is a wireless LAN standard developed by the IEEE in order to specify an {"}over the air{"} interface between a wireless client and a base station or Access Point, as well as among wireless clients. The legacy standard specifies a 2.4 GHz operating frequency using frequency hopping or direct sequence modulation with initial data rates of 1 or 2 Mbps. But, later revisions have used modulation techniques like OFDM and CCK and increased the data rate tremendously and recently the IEEE 802.11g is providing date rates up to 54 Mbps. Performance analysis shows the bottleneck of the standard in terms of several chosen parameters. And, scalability analysis shows that whether WLAN is able to sustain the performance in different environment settings. Without the support of strong analysis the acceptance of WLAN devices will not be widespread. This paper presents performance and scalability analysis of IEEE 802.11 implemented in Network Simulator (NS-2) [5]. The simulation is carried out in a wired cum wireless environment as shown in Figure 1. Both TCP [1] and CBR [1] traffic types are chosen for simulation. The performance metrics that we have chosen are throughput, delay and packet drop. We investigate the effect of topology, the effect of node movement and the effect of date-rate increase on the aforementioned performance metrics. From the simulation, the highest throughput is found to be around 1.7 Mbps (See Figure 2). Also, the packet drop and the delay are found to be increasing as we increase the area and node-movement speed. The simulation results are closer to the theoretical values and simulator dependent. Future work can include the performance analysis of IEEE 802.11 for different routing protocol and developing an analytical model for interference mechanism to simulate the packet loss, jitter, throughput and delay. References: 1. Andrew S. Tanenbaum, Computer Networks, Third Edition, Prentice Hall, 1996. 2. P. Chatzimisios, V. Vitsas, A. C. Boucouvalas, Throughput and Delay Analysis of IEEE 802.11 Protocol, Proc. of the 5th IEEE International Workshop on Networked Appliances, Oct. 30-31, 2002, Liverpool John Moores University, UK, pp. 168-174 3. W. Stallings, Wireless Communications and Networks, Prentice Hall, 2002. 4. DCM Technologies, White Paper in IEEE 802.11 techonology. 5. Network Simulator (NS-2), http://www.isi.edu/nsnam.} } @INPROCEEDINGS{Abe0503:Microwave, AUTHOR="Hiroshi Abe", TITLE="Microwave Operation of On-chip Antenna Embedded in {WL-CSP}", BOOKTITLE="IEEE International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials", ADDRESS="Marina Mandarin Singapore", DAYS=1, MONTH=mar, YEAR=2005, ABSTRACT="An on-chip antenna for microwave operation is demonstrated. Application of wafer-level chip-scale package (WL-CSP) techniques such as dual Cu electroplating conductive layers and thick resin layers separating the conductive layer more than 10 mm from Si substrate allow on-chip integration. Details of antenna fabrication process and performance are presented. Antenna performance achieved the maximum communication range between the on-chip antenna and a transmission module over 400 mm at a transmission signal power of 300 mW. WL-CSP techniques realize real chip-scale long communication range radio frequency identification (RFID) tag." } @INPROCEEDINGS{Abed0506:Convergence, AUTHOR="Ali Abedi and Saeed Gazor", TITLE="Convergence Analysis of {Turbo-Codes} Using Moment Evolution", BOOKTITLE="Canadian Workshop on Information Theory", ADDRESS="Montreal, Quebec", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="The problem of convergence analysis of Turbo-codes has been investigated from a new point of view. The evolution of moments of the bit Log-Likelihood Ratio (LLR) during iterative decoding is studied. Since convergence of the moment estimation is equivalent to the convergence of the Bit Error Rate (BER) calculations, we study the convergence of the turbo decoder using moment method. The proposed method provides new insights on stopping criteria for iterative decoding." } @INPROCEEDINGS{Abel0506:Inherently, AUTHOR="Jaume Abella and Antonio Gonzalez", TITLE="Inherently {Workload-Balanced} Clustered Microarchitecture", BOOKTITLE="19th International Parallel and Distributed Processing Symposium", DAYS=3, MONTH=apr, YEAR=2005, ABSTRACT="The performance of clustered microarchitectures relies on steering schemes that try to find the best trade-off between workload balance and inter-cluster communication penalties. In previously proposed clustered processors, reducing communication penalties and balancing the workload are opposite targets, since improving one usually implies a detriment in the other. In this paper we propose a new clustered microarchitecture that can minimize communication penalties without compromising workload balance. The key idea is to arrange the clusters in a ring topology in such a way that results of one cluster can be forwarded to the neighbor cluster with a very short latency. In this way, minimizing communication penalties is favored when the producer of a value and its consumer are placed in adjacent clusters, which also favors workload balance. The proposed microarchitecture is shown to outperform a state-of-the-art clustered processor. For instance, for an 8-cluster configuration and just one fully pipelined unidirectional bus, 15\% speedup is achieved on average for FP programs." } @INPROCEEDINGS{Aben0505:Multiple, AUTHOR="Dirk Abendroth and {van den Berg} and Michel Mandjes", TITLE="A multiple time-scale model for {TCP} bandwidth sharing under user heterogeneity", BOOKTITLE="NETWORKING 2005", ADDRESS="Waterloo, Ontario, Canada", DAYS=2, MONTH=may, YEAR=2005, ABSTRACT="Building on the vast body of existing TCP models, we develop a novel versatile model that explicitly captures user heterogeneity, and takes into consideration dynamics at both the packet level and the flow level. It is described how the resulting multiple time-scale model can be numerically evaluated. Validation is done by using NS2 simulations as a benchmark. In extensive numerical experiments, we study the impact of heterogeneity in the round-trip times on user-level characteristics such as throughputs and flow transmission times, thus quantifying the resulting bias. In particular, we investigate to what extent this bias is affected by the networks' `packet-level parameters', such as buffer sizes. We conclude by extending the single-link model in a straightforward way to the general network setting." } @INPROCEEDINGS{Abha0505:Comparison, AUTHOR="Viraj Abhayawardhana and Ian Wassell and David Crosby and Malcolm Sellars and Martin Brown", TITLE="Comparison of Empirical Path Loss Models in Fixed Wireless Access Systems", BOOKTITLE="Vehicular Technology Conference Spring 2005 Antennas and Propagation", ADDRESS="Stockholm, Sweden", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="Empirical propagation models have found favour in both research and industrial communities owing to their speed of execution and their limited reliance on detailed knowledge of the terrain. Although the study of empirical propagation models for mobile channels has been exhaustive, their applicability for FWA systems is yet to be properly validated. Among the contenders, the ECC-33 model the Stanford University Interim (SUI) models and the COST-231 Hata model show the most promise. In this paper, a comprehensive set of propagation measurements taken at 3.5 GHz in Cambridge, UK is used to validate the applicability of the three models mentioned previously for rural, suburban and urban environments. The results show that in general the SUI and the COST-231 Hata model over-predict the path loss in all environments. The ECC-33 models shows the best results, especially in urban environments." } @INPROCEEDINGS{Abic0505:CONTI, AUTHOR="Zakhia Abichar and J. Morris Chang", TITLE="{CONTI:} {Contant-Time} Contention Resolution for {WLAN} Access", BOOKTITLE="NETWORKING 2005", ADDRESS="Waterloo, Ontario, Canada", DAYS=2, MONTH=may, YEAR=2005, ABSTRACT="Designing an efficient and fair access control protocol is a challenging task in the field of wireless networks. Often in the known schemes, one of the important performance metrics is enhanced at the expense of another. In this paper, we present a distributed access scheme that is based on the binary countdown mechanism. The proposed scheme has two main features: 1) the ability to resolve the contention in a constant number of time slots, hence the name constant-time (CONTI) and 2) a very low collision rate even at large network sizes. The simulation results show that CONTI outperforms the IEEE 802.11 DCF scheme in all the essential performance metrics: CONTI achieves a higher throughput by up to 55\%, reduces the collision rate by up to 84\%, renders the delay less variant and exhibits optimal fairness." } @INPROCEEDINGS{Abid0504:Improving, AUTHOR="Mohamed Abid and Hahnsang Kim and Hossam Afifi and Farouk Kamoun", TITLE="Improving Mobile Authentication: evaluation of new protocol {EAP-Bluetooth}", BOOKTITLE="International Workshop on Systems and Network Security", ADDRESS="Denver, Colorado", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="Abstract -- Wireless networking, more than any other networking technology, needs an Authentication and Access Control mechanism. In this work, to allow an efficient authentication in public domain, we developed a new solution based on vertical handover named EAP-Bluetooth. We used the security features given in Wi-Fi and Bluetooth. The solution aimed to secure the exchange of the Personal Identifier Number (PIN) needed in Bluetooth to generate the Link Key by using wireless security. We also perform some simulations, using NS-2, to evaluate the response time of EAP-Bluetooth. Keywords -- authentication, Bluetooth, EAP, EAP-Bluetooth, IEEE 802.1X, Security, vertical handover, Wi-Fi. ." } @INPROCEEDINGS{Abol0505:Simplex, AUTHOR="Bahman Abolhassani and Eric Salt", TITLE="A Simplex {K-Means} Algorithm for {Radio-Port} Placement in Cellular Networks", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="To increase capacities of cellular networks, large cells must be replaced by micro and/ or pico cells. Employing small cells increases the number of radio-ports required to cover the same service area. Therefore, optimal placement of radio-ports can minimize the number of radio-ports and reduce the deployment costs, and at the same time, it provides the same required coverage. This paper proposes a hybrid of the Nelder-Mead simplex and K-means algorithms. The algorithm minimizes the maximum path loss experienced by wireless portable handsets. The performance of the proposed algorithm is compared with those of the Quasi-Newton algorithm, as well as the exhaustive search. Simulation results show that the simplex K-means algorithm finds better radio-port placements, especially for larger floor plans." } @INPROCEEDINGS{Abol0511:Efficient, AUTHOR="Mehran Abolhasan", TITLE="Efficient and Highly Scalable Route Discovery for On-demand Routing Protocols in Ad hoc Networks", BOOKTITLE="The 30th Annual IEEE Conference on Local Computer Networks (LCN)", ADDRESS="Syndey, Australia", DAYS=15, MONTH=nov, YEAR=2005, ABSTRACT="This paper presents a number of different route discovery strategies for on-demand routing protocols, which provide more control to each intermediate node make during the route discovery phase to make intelligent forwarding decisions. This is achieved through the idea of self-selection. In self-selecting route discovery each node independently makes Route Request (RREQ) forwarding decisions based upon a selection criterion or by satisfying certain conditions. The nodes which do not satisfy the selection criterion do not rebroadcast the routing packets. We implemented our self-selecting route discovery strategies over AODV using the GloMoSim network simulation package, and compared the performance with existing route discovery strategies used in AODV. Our simulation results show that a significant drop in the number of control packets can be achieved by giving each intermediate node more authority for self-selection during route discovery. Furthermore, a significant increase in throughput is achieved as the number nodes in the network is increased." } @INPROCEEDINGS{Abou0405:Impact, AUTHOR="Mohamed Abou-Khousa and Ali Ghrayeb and Mohamed El-Tarhuni", TITLE="On the Impact of Imperfect Multipath Detection on the Performance of {CDMA} Systems with {Space-Time} Spreading", BOOKTITLE="Vehicular Technology Conference Spring 2005 Transmission Technology", ADDRESS="Stockholm, Sweden", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="In this paper, we investigate the impact of imperfect multipath detection on the performance of CDMA systems employing space-time spreading. Conventionally, the multipath components are detected and assigned to the RAKE fingers based on their average energy content. It will be shown that the errors produced by the conventional scheme in detecting the potential multipath components severely impact the performance of the receiver. To boost the performance, we introduce an improved multipath detection scheme based on estimating the interference power in the resolved paths. Preliminary results show that the proposed scheme not only improves the BER performance significantly but also utilizes the pilot power more efficiently." } @INPROCEEDINGS{Abou0505:Modeling, AUTHOR="Ahmed Aboul-Seoud and Moataz Soliman and Alaa Hafez", TITLE="Modeling of {AlxGa1-xAs/GaAs} Multi Quantum Well Photodetector {(MQWP)}", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="This paper is devoted to simulate the spectral response of multiple AlxGa1-xAs/GaAs quantum wells photodetector (MQWP), using a self-consistent model. The model is based on the solution of semiconductor transport equations in the bulk regions and Schr\ödinger equation to model the carrier concentration inside the quantum wells. The model includes the capture, escape, and recombination of photoexcited carriers in the quantum wells. The structure is an AlxGa1-xAs p-i-n photodiode with or without GaAs quantum wells in the intrinsic layer. In the AlGaAs regions of the device, where electrons and holes behave as bulk carriers with no quantum confinement, the current continuity, current density, and Poissons equations are used. These equations are solved simultaneously using the boundary finite-difference method in one-dimensional steady state case. Quantum well carrier concentration equations depend on the quantized energy levels and the wavefunctions in the quantum well. These eigenenergies and eigenfunctions are obtained from a field dependent Schr\ödinger equitation. Schr\ödinger equation is solved for a finite square quantum well for the energy levels and for infinite square well for the wave function. This quantum well model is presently limited to the inclusion of only the lowest of each electron and hole energy levels. A good agreement was obtained when comparing the results of this model with these obtained from experimental results. We found that the present model reproduces the photodetector spectral response closer to the experimental data than the previous theoretical model. This model can be used to optimize the structure to maximize the photocurrent, and as tool to study the effect of different device parameters on its performance. We found that reducing the p-layer thickness improves the spectral response of the device in the short wavelengths range. Also increasing the aluminum mole fraction x increase the absorption of photons in the short wavelengths range but the counteracting effect decreases the absorption of photons in red and infrared range. Increase the quantum well width improves the spectral response in the long wavelengths range." } @INPROCEEDINGS{Abou0505:Multipath, AUTHOR="Mohamed Abou-Khousa and Ali Ghrayeb and Mohamed El-Tarhuni", TITLE="On Multipath Detection in {CDMA} Systems", BOOKTITLE="ICC 2005 Signal Processing for Communications", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="This paper addresses the problemofmultipath detection in CDMA systems. In conventional CDMA receivers, the detection of multipath components and RAKE finger management is normally based on the received signal energy per path. In essence, these schemes overlook the interference component contaminating the total received power. Consequently, they exhibit poor detection capability especially at low signal-to-interference ratio (SIR). In this paper, we present a new scheme for multipath detection and RAKE finger assignment based on estimating the interference power per path. It will be shown that the proposed scheme provides significant improvements in the detection probability of multipath components over the energy-based schemes. For instance, with the proposed scheme, a reduction of at least 4 dB in the pilot power is realizable." } @INPROCEEDINGS{Abou0509:Impact, AUTHOR="Abdulla Abouda and Hassan El-Sallabi and Gustav Haggman", TITLE="Impact of Antenna Array Geometry on {MIMO} Channel Eigenvalues", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="Spatial correlation properties of MIMO channel highly depend on the propagation environment and the antenna array geometry. In this paper the impact of different antenna array geometries on MIMO channel eigenvalues is investigated in realistic microcellular propagation environment for different scenarios. Four different antenna array geometries are considered, namely, uniform linear array, uniform circular array, uniform rectangular array and uniform cubic array. All the considered geometries have same number of elements and fixed inter-element spacing. The uniform linear array geometry shows superiority to the other considered geometries." } @INPROCEEDINGS{Abou0509:Optimal, AUTHOR="Roger Abou-Jaoude", TITLE="Optimal {HSDPA} Multi-cell Power Allocation in a Moving Hotspot Scenario", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="In the context of dynamic network management, the HSDPA power allocation in each cell is considered in this paper as a mean of assigning resources through a wireless network in an autonomic way. Under the umbrella of end-to-end reconfigurability as stated in the E2R EU funded project, dynamic management is enabled by allowing on the fly reconfiguration of network parameters, leading to an optimized use of resources and more flexibility in allocating resources of heterogeneous networks based on demand. The test scenario consists of a moving hotspot, where users are served by a high speed shared data channels. All available spreading codes are given to one user at a time, and a queuing model based on M/G/1-PS is used to evaluate the throughput and the response time both in the hotspot cell and the neighboring cells. A basic algorithm consisting of a total cell power allocation proportional to the number of user waiting to be served is investigated, of which gains in terms of hotspot throughput were proven to be higher than the losses incurring in neighboring and less populated cells. A typical scenario where the hotspot occurs is for example when users move to an area known to be crowded at a certain point of time during the day, but then move again to a neighboring area due to another interest there. The hotspot could also occur in an unexpected way (traffic jam, special events), and resources have to be adapted intelligently and autonomously. The efficiency of such an algorithm is investigated in terms of different parameters. Moreover, in the course of looking for a boundary for the performance of such an algorithm, we propose a simulated annealing based approach to find the optimal power distribution to evaluate the proximity of simpler and faster algorithms to such an optimum." } @INPROCEEDINGS{Abou0511:Simulation, AUTHOR="Neda Aboutorab", TITLE="Simulation of Fully Adaptive Beamformer Using Maximum {Signal-to-Interference} and Noise Ratio Algorithm for Narrowband Signals in Flat Fading Channels", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="This extended abstract presents the simulation of fully adaptive beamformer using Maximum Signal-to-Interference and Noise Ratio Algorithm for Narrowband Signals in Flat Fading Channels. Simulation results confirm the preferences of the proposed algorithm over other well known algorithms such as Null Steering algorithm." } @INPROCEEDINGS{Abra0505:802, AUTHOR="Santosh Abraham and Arnaud Meylan and Sanjiv Nanda", TITLE="802.11n {MAC} Design and System Performance", BOOKTITLE="ICC 2005 Wireless Networking", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="In this paper we present an overview of the MAC and PHY layer enhancements required to ensure high application layer throughput for IEEE 802.11n. We present an enhanced scheduled mode operation which is shown, through simulation, to yield an application layer throughput that is greater than 100Mb/s. We also demonstrate that the proposed enhancements significantly improve the application layer throughput for EDCA." } @TECHREPORT{Abra0507:Papillon, AUTHOR="Ittai Abraham and Dahlia Malkhi and Gurmeet Manku", TITLE="Papillon: Greedy Routing in Rings", TYPE="arXiv report", INSTITUTION="arXiv", NUMBER="cs.DC/0507034", MONTH=jul, YEAR=2005, ABSTRACT="We study greedy routing over $n$ nodes placed in a ring, with the distance between two nodes defined to be the clockwise or the absolute distance between them along the ring. Such graphs arise in the context of ing social networks and in routing networks for peer-to-peer systems. We construct the first network over $n$ nodes in which sc greedy routing takes $O(\log n / \log d)$ hops in the worst-case, with $d$ out-going links per node. Our result has the first asymptotically optimal greedy routing complexity. Previous constructions required $O(\frac{\log2 n}{d})$ hops.", URL="http://arxiv.org/abs/cs/0507034" } @INPROCEEDINGS{Abra0509:Congestion, AUTHOR="Filipe Abrantes and Manuel Ricardo", TITLE="On Congestion Control for Interactive Real-time Applications in Dynamic Heterogeneous {4G} Networks", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="Real-time multimedia applications, such as VoIP, video conferencing or on-line gaming are key applications to the success of 4G. In today's Internet these applications are not subject to congestion control, therefore the growth of popularity of these applications may endanger the stability of the Internet. On the other hand, 4G networks will be much more dynamic due to mobility and multi-homing, and the network conditions may vary abruptly requiring a fast response from the control mechanism. In this article we compare the feedback-based to the reservation-based congestion control approach and focus on the first one, by evaluating some mechanisms with respect to Media Friendliness, Scalability and Dynamic Behaviour. We also present a set of requirements for the ideal congestion control mechanism of real-time flows in 4G networks." } @INPROCEEDINGS{Abre0509:Performance, AUTHOR="Giuseppe Abreu", TITLE="Performance of Parameter Estimation from {UWB-IR} Signals an Array of Orthonormal Correlators", BOOKTITLE="2005 IEEE International Conference on Ultra-Wideband", ADDRESS="Zurich", DAYS=5, MONTH=sep, YEAR=2005, ABSTRACT="\% A method for the estimation of physical parameters from ultra-wideband (UWB) Gaussian impulsive waveforms utilizing an array of correlation filters is introduced. Modeling the UWB pulses by Hermite wavelets, and relying on closed-form correlation formulae for such waveforms, the output vectors of an arrays of correlator can be mathematically described. The formulation brings the problem of parameter estimation from UWB impulsive signals to conditions similar to those of conventional narrowband arrays, eliminating the need for prohibitively complex spatial-temporal signal decomposition. The effectiveness of the approach is theoretically demonstrated through Cramar-Rao lower bound analysis." } @INPROCEEDINGS{Abu-0504:Scheduling, AUTHOR="Osama Abu-Sharkh and Ahmed Tewfik", TITLE="A Scheduling Scheme to Enhance Throughput In Infrastructure-mode {802.11} {WLANs}", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="In 802.11 infrastructure-mode some stations that are located far away from an access point may face signal fading and interference. In this case, the wireless station changes its data rate to some lower value. In 802.11b protocol, wireless stations can operate at data rates 11, 5.5, 2 and 1 Mbps. From the literature, our simulation, we found that when some wireless stations use a lower data rate than others, the performance of all stations is degraded. The throughput of all wireless stations, including fast and slow, ones is decreased to the order of magnitude of the slow station. This is due to the CSMA/CA channel access method used in 802.11 which guarantees that the long term channel access probability is equal for all wireless stations. In this paper, we introduce a TDMA based scheduling scheme that avoids slow stations from penalizing other ones transmitting at higher rates." } @INPROCEEDINGS{Abu-0505:Throughput, AUTHOR="Osama Abu-Sharkh and Ahmed Tewfik", TITLE="Throughput Evaluation and Enhancement in {802.11} {WLANs} with Access Point", BOOKTITLE="Vehicular Technology Conference Spring 2005 Wireless Access", ADDRESS="Stockholm, Sweden", DAYS=28, MONTH=may, YEAR=2005, ABSTRACT="In 802.11 infrastructure mode some stations that are located far away from an access point may face signal fading and interference. In this case, the wireless station changes its data rate to some lower value. In 802.11b protocol, wireless stations can operate at data rates 11, 5.5, 2 and 1 Mbps. From the literature, our simulation, and experimentation we found that when some wireless stations use a lower data rate than others, the performance of all stations is degraded. The throughput of all wireless stations, including fast and slow, ones is decreased to the order of magnitude of the slow station. This is due to the CSMA/CA channel access method used in 802.11 which guarantees that the long term channel access probability is equal for all wireless stations. In this paper, we propose a solution that avoids slow stations from penalizing other ones transmitting at higher rates. The solution is based on using frames of different sizes according to the link data rate." } @INPROCEEDINGS{Abu-0509:Performance, AUTHOR="Osama Abu-Sharkh and Ahmed Tewfik", TITLE="Performance Analysis of {Multi-Rate} {802.11} {WLANs} Under Finite Load And Saturation Conditions", BOOKTITLE="VTC'F05 Modeling and Simulation", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="In IEEE 802.11 WLANs, stations can operate at different data rates. For example, in 802.11b, wireless stations transmit at four date rates 11, 5.5, 2 and 1 Mbps. A station changes its modulation type and transmits at a lower rate when it faces signal fading and interference. In this paper we introduce a model to cope with the capability of the standard to operate at different data rates under finite load and saturation conditions. Many improvements are also made in order to make the model more consistent with the standard and super perform the existing models. The proposed analysis applies to both the basic access and the RTS/CTS access mechanisms. Extensive throughput performance evaluation is provided and an analytical expression for average service time is also given. Simulation and Experiments were performed to validate the model." } @INPROCEEDINGS{Abu-0511:Multi, AUTHOR="Osama Abu-Sharkh and Ahmed Tewfik", TITLE="{Multi-Rate} {802.11} {WLANs}", BOOKTITLE="Globecom 2005 Wireless Communications", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="In IEEE 802.11 WLANs, stations can operate at different data rates. For example, in 802.11b, wireless stations transmit at four date rates 11, 5.5, 2 and 1 Mbps. A station changes its modulation type and transmits at a lower rate when it faces signal fading and interference. In this paper we introduce a model to capture the capability of the standard to operate at different data rates under both, finite load and saturation conditions. Many improvements are also made in order to make the model more consistent with the standard than existing models. The proposed analysis applies to both the basic access and the RTS/CTS access mechanisms. The results we obtained from the model also show the performance anomaly of the standard when it operates at different data rates that was previously observed in the literature, and our experiments and simulation. We use the model to study a scheme we proposed earlier to avoid the degradation in the performance by changing the frame sizes of the stations according to their speeds. Throughput performance evaluation is provided and an analytical expression for average service time is given. Experiments were performed to validate the model." } @INPROCEEDINGS{Abus0503:Novel, AUTHOR="David Abusch-Magder and John Graybeal", TITLE="Novel Algorithms for Reducing Cell Sites During a Technology Upgrade and Network Overlay", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="The development of newer generations of technology has created the opportunity and need for wireless providers to upgrade their networks (e.g. 2G to 3G), while market forces require them to maximize the use of their capital and preexisting investments. Upgrades in technology not only offer additional services but also performance enhancements which give the operator the opportunity to achieve comparable network wide coverage with fewer cells. We propose a simple yet novel algorithm for choosing those cells that can be deleted during such an upgrade, and compare its performance and speed to other algorithms used to address related combinatorial optimization problems. We present an intuitive example to demonstrate the role of inhomogeneity in network performance, and show how the opportunities for cell deletion increase with the amount of network inhomogeneity; in addition we apply these algorithms to a realistic network and compare their performance." } @INPROCEEDINGS{Acen0505:Spectral, AUTHOR="Miguel Acena and Stephan Pfletschinger", TITLE="A Spectral Efficient Method for Subcarrier and Bit Allocation in {OFDMA}", BOOKTITLE="Vehicular Technology Conference Spring 2005 Wireless Access", ADDRESS="Stockholm, Sweden", DAYS=28, MONTH=may, YEAR=2005, ABSTRACT="In this paper we propose and evaluate a new method for assigning subcarriers, constellation sizes and power to the users in an OFDMA system. The proposed scheme considers user-individual bit rate and power constraints, maximum constellation sizes and a spectral power density (PSD) mask. The algorithm minimizes the total used bandwidth by reserving as many subcarriers as possible for future users. By applying this algorithm in a WLAN environment we found that only very few additional transmit power is required in order to reserve a significant amount of subcarriers, even when compared to the best-known power-minimizing algorithm. The computational complexity of the algorithm is very low, which makes it suitable for practical implementation." } @INPROCEEDINGS{Acha0504:Secure, AUTHOR="Mithun Acharya and Joao Girao and Dirk Westhoff", TITLE="Secure Comparison of Encryted Data in Wireless Sensor Networks", BOOKTITLE="3rd International Symposium on Modeling and Optimization in Mobile,Ad-hoc and Wireless Networks", ADDRESS="Riva del Garda, Trentino, Italy", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="End to end encryption schemes that support operations over ciphertext are of utmost importance for commercial private party Wireless Sensor Network (WSN) implementations to become meaningful and profitable. For WSNs we demonstrated in our previous work that homomorphic encryption schemes, when used for concealed data aggregation (CDA), offer two striking advantages apart from end-to-end concealment of data and ability to operate on ciphertexts: flexibility by keyless aggregation and conservation and balancing of aggregator backbone energy. We offered proof of concept by applying a certain Privacy Homomorphism for sensor network applications that rely on the addition operation. But a large class of aggregator functions like median computation or finding maximum/minimum rely exclusively on comparison operations. Unfortunately any Privacy Homomorpshism is insecure even against ciphertext only attacks, if they support comparsion operations. In this paper we show that a particular order preserving encryption scheme achieves the above mentioned energy benefits and flexibility when used to support comparison operations over encrypted texts for Wireless Sensor Networks, while also managing to hide the plaintext distribution and being secure against ciphertext only attacks. The scheme is shown to have reasonable memory and computation overhead when applied for WSNs." } @INPROCEEDINGS{Acos0503:Unstructured, AUTHOR="William Acosta and Surendar Chandra", TITLE="Unstructured {Peer-to-Peer} Networks - Next Generation of Performance and Reliability", BOOKTITLE="IEEE INFOCOM 2005 Poster/Demo session", ADDRESS="Miami, FL, USA", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="In this poster we will present our work on the design of efficient and reliable unstructured peer-to-peer (P2P) systems. Our work focuses on creating well-connected unstructured P2P overlay that can perform efficient searching and message routing. We show that well designed systems can tolerate high node failures (>25\%) while maintaining connectivity and still resolving searches with few messages. This is important in applications such as file sharing and content distribution where there are many thousands of participating nodes that are widely dispersed and network coniditions are highly variable. Structured P2P systems are not suitable for these applications since such applications require multi-attribute and wild card searching. We show that carefully constructed overlays can resolve this type of search within 4 hops for large networks (> 10,000 nodes) with low object replication ratios (< 1\%)." } @INPROCEEDINGS{Acs0507:Provable, AUTHOR="Gergely Acs and Levente Buttyan and Istvan Vajda", TITLE="Provable Security of {On-Demand} Distance Vector Routing in Wireless Ad Hoc Networks", BOOKTITLE="2nd European Workshop on Security and Privacy in Ad Hoc and Sensor Networks", ADDRESS="Visegrad, Hungary", DAYS=14, MONTH=jul, YEAR=2005, ABSTRACT="In this paper, we propose a framework for the security analysis of on-demand, distance vector routing protocols for ad hoc networks, such as AODV, SAODV, and ARAN. The proposed approach is an adaptation of the simulation paradigm that is used extensively for the analysis of cryptographic algorithms and protocols, and it provides a rigorous method for proving that a given routing protocol is secure. We demonstrate the approach by representing known and new attacks on SAODV in our framework, and by proving that ARAN is secure in our model." } @INPROCEEDINGS{Adac0505:Multi, AUTHOR="Fumiyuki Adachi and Kazuaki Takeda and Hiromichi Tomeba", TITLE="Multi-antenna {Pre-Equalization} for Single {Carrier/TDD} System", BOOKTITLE="Vehicular Technology Conference Spring 2005 Transmission Technology", ADDRESS="Stockholm, Sweden", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="Multi-antenna pre-equalization in the frequency-domain (pre-FDE) is presented for improving the transmission performance of single carrier (SC) system. At a transmitter, pre-FDE with power constraint is applied for each transmit antenna. A simple data demodulation function is only required at a receiver. It is shown by the computer simulation that multi-antenna pre-FDE can provide significant performance improvement in a frequency-selective Rayleigh fading channel." } @INPROCEEDINGS{Adac0509:Bit, AUTHOR="Fumiyuki Adachi and Haris Gacanin and Shinsuke Takaoka", TITLE="Bit Error Rate Analysis of {OFDM/TDM} with Frequency-domain Equalization", BOOKTITLE="VTC'F05 Transmission Technology", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="Orthogonal frequency division multiplexing (OFDM) has high peak-to-average power ratio (PAPR) problem. Recently, the OFDM combined with time domain multiplexing (TDM) using frequency-domain equalization (FDE) was proposed to overcome the PAPR. In this paper, the theoretical bit error rate (BER) analysis of the OFDM/TDM is presented. The conditional BER expression is derived for the given set of channel gains. Various FDE techniques, i.e., zero forcing (ZF), maximum ratio combining (MRC) and minimum mean square error (MMSE) criterion, are considered. The average BER performance is evaluated by Monte-Carlo numerical computation method using the derived conditional BER expression and is confirmed by computer simulation." } @INPROCEEDINGS{Adam0502:Performance, AUTHOR="Davide Adami and Stefano Giordano and Matteo Repeti and Piero Castoldi and Filippo Cugini and Luca Valcarenghi", TITLE="Performance evaluation of recovery techniques in a Grid-oriented {Metrocore/VESPER} field trial", BOOKTITLE="Testbeds and Research Infrastructures for the DEvelopment of NeTworks and COMmunities", ADDRESS="Trento (Italy)", DAYS=21, MONTH=feb, YEAR=2005, ABSTRACT="The introduction of advanced features provided by the emerging next generation networks based on the Generalized Multi-Protocol Label Switching (GMPLS) protocol framework in grid computing systems promises to significantly improve the performance of distributed applications and services. An accurate experimental analysis of the main GMPLS features, such as the different reliability solutions, is then required. In this paper, we present the experimental implementation of different reliability solutions in the Metrocore/VESPER field trial, the high-performance network infrastructure located in Pisa, Italy. Protection and restoration schemes are investigated both at the IP/MPLS and physical layer." } @INPROCEEDINGS{Adam0504:Performance, AUTHOR="Davide Adami and Stefano Giordano and Michele Pagano and Matteo Repeti and Nora Carlotti", TITLE="Performance Study of the Control and Forwarding Planes in a High Speed {MPLS} Network", BOOKTITLE="1st EuroNGI Conference on Next Generation Internet Networks - Traffic Engineering", ADDRESS="Rome, Italy", DAYS=18, MONTH=apr, YEAR=2005, ABSTRACT="Multiprotocol Label Switching (MPLS) was originally conceived to improve the efficiency of packet forwarding in network equipments and it relies on a strict separation between the control and forwarding planes in the network functions as well as in the software and hardware architecture of the routers. The paper presents the results of an experimental study aimed at evaluating the performance of the control and forwarding planes in a metropolitan MPLS network, interconnecting three sites, located in Pisa and equipped with M10 Juniper routers. In particular, experimental tests have been carried out to deeply investigate the behaviour of the network control and forwarding planes in different working conditions." } @INPROCEEDINGS{Adam0506:Scalable, AUTHOR="Robert Adams and Paul Brett and Dejan Milojicic and Sandro Rafaeli and Vanish Talwar and Subu Iyer", TITLE="Scalable Management", BOOKTITLE="IEEE International Conference on Autonomic Computing", ADDRESS="Seattle, Washington", DAYS=13, MONTH=jun, YEAR=2005, ABSTRACT="Modern computing environments, such as enterprise data centers, Grids, and PlanetLab introduce distributed services to address scalability, locality, and reliability. Web Services (WS), in particular, improve decoupling, decentralization, and autonomicity within distributed systems. Unfortunately, scale and decentralization introduce additional problems in distributed services management, such as deployment, monitoring, and lifecycle maintenance. In this paper, we propose a new approach to management of large scale distributed services, based on three artifacts: unreliable publish-subscribe eventing, scalable WS-based deployment, and model-based management. We demonstrate that these techniques improve the manageability of services. This way we enable service developers to focus on the development of service functionality rather than on management features." } @INPROCEEDINGS{Adam0511:Signalling, AUTHOR="Davide Adami and Christian Callegari and Stefano Giordano and Fabio Mustacchio and Michele Pagano and Fabio Vitucci", TITLE="Signalling Protocols in Diffserv-aware {MPLS} Networks: Design and Implementation of {RSVP-TE} Network Simulator", BOOKTITLE="Globecom 2005 Advances for Networks \& Internet", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="In a multi-service IP network, it is a key challenge to provide Quality of Service (QoS) to end-user applications while effectively using network resources. The DiffServ architecture has emerged as a scalable solution to provide a network design with multiple service classes. The MultiProtocol Label Switching (MPLS) Traffic Engineering (TE), instead, enables resource reservation, fault-tolerance and optimization of transmission resources. MPLS DiffServ-aware TE combines the advantages of these solutions and allows network operators to provide services that require strict QoS performance guarantees. The choice of the signalling protocol to exchange DiffServ, MPLS and TE-related information is a key point in this scenario. Different solutions have been proposed, such as RSVP-TE and CR-LDP. Since the first one seems to be the most attractive solution for router manufacturers, in this paper, the design and the development of a new software module to simulate the RSVP-TE protocol in the Network Simulator 2 (NS2) is presented. This module could be useful to speed-up the design, development and deployment of DiffServ-aware MPLS networks." } @INPROCEEDINGS{Adea0506:Optimum, AUTHOR="Jaime Adeane and Miguel Rodrigues and Ian Wassell", TITLE="Centralised and Distributed Power Allocation Algorithms in Cooperative Networks", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="Cooperation among network users provides transmit diversity in cases where wireless transmitters, due to size and power limitation, cannot support multiple antennas. We consider cooperation among $M$ users, where each user achieves space-time diversity by using other users' antennas as relays. Cooperation among users has been shown to achieve impressive BER gains as compared to a non-cooperative system while maintaining the same information rate, transmit power, and bandwidth. This paper formulates an optimum power allocation scheme appropriate for a cooperative network using transparent relaying. It will be shown that the proposed allocation scheme significantly outperforms the equal power allocation scheme, e.g., by up to 5 dB for a 3-user case at a bit error rate of 10^(-3). The results presented here may serve as a reference for the performance assessment of sub-optimal (but practical) algorithms." } @INPROCEEDINGS{Aded0505:Evolutionary, AUTHOR="Steven Adedoyin and Anil Fernando and Kok Keong Loo and Hemantha {Kodikara Arachchi}", TITLE="An Evolutionary Strategy Based Motion Estimation Algorithm for {H.264} Video Codec", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="The new H.264 video coding standard developed jointly by the Video Coding Experts Group (VCEG) of ITU and the Motion Picture Experts Group (MPEG), i.e. Joint Video Team (JVT), provides a versatile coding format, accommodating a wider variety of bandwidth requirements, picture formats and unfriendly network environments that may possess high jitter, packet loss, and bandwidth instability. Although the features of H.264 make it viable for many applications, many alterations, extensions and optimisations have to be made before it can be applied to such systems. The vastly improved coding efficiency of H.264 comes at a price of complexity, which may not be realizable for real time transmission. In order to be attractive enough for it to be adopted by commercial organisations / industry, it is required to encode in real-time. Unfortunately due to the stringent requirements governing the design and operational simplicity of standardized H.264 decoder and the optimisations thus involved, increases the encoder complexity beyond real-time capability. Motion estimation is the most complex part and it takes about 40\% computational cost of the encoder. In this paper, we propose a new motion estimation algorithm based on evolutionary strategy (ES) for the H.264 video codec as shown in Figure 1. Evolutionary strategy is a kind of evolutionary algorithm where individuals (potential solution) are encoded by a set of real-valued object variables. For each object variable an individual also has a strategy variable which determines the degree of mutation to be applied to the corresponding object variable. The strategy variables also mutate, allowing the rate of mutation of the object variables to vary. Experimental results show that the proposed scheme can reduce the error signal to a very low value and therefore the proposed scheme can compress the video sequence significantly. Furthermore, the computational complexity of the proposed scheme is reduced up to 30\% of the motion estimation algorithm used in the H.264 reference codec. Therefore, the proposed algorithm provides a significant improvement in motion estimation in the H.264 video codec." } @INPROCEEDINGS{Adel0511:Dynamic, AUTHOR="Ferran Adelantado and Fernando Casadevall-Palacio", TITLE="Dynamic Common Pilot Power Management in a Real Hot Spot Environment.", BOOKTITLE="Globecom 2005 Wireless Communications", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="This paper focuses on the analysis of 3G mobile communications systems in scenarios with non-uniformly distributed traffic. Special attention is paid to the impact of hot spots on uplink BLER and admission control. Load balance is carried out by dynamically varying common pilot power. Results reveal that the performance of the system in the uplink may be improved when applying such technique." } @INPROCEEDINGS{Adey0511:Impact, AUTHOR="Adesegun Adeyemo", TITLE="The Impact of Dynamic Spectrum Access Network On Third World Countries: Spectrum Allocation Issues, Network and Economic Growth (The African Tale)", BOOKTITLE="First IEEE International Symposium on New Frontiers in Dynamic Spectrum Access Networks", ADDRESS="Baltimore, MD USA", DAYS=8, MONTH=nov, YEAR=2005, ABSTRACT="Africa, undoubtedly the fastest growing mobile technology market is faced with challenges in the allocation of spectrum. Coping with the astronomical growth in the number of the spectrum users and effect of the mode of implementation of spectrum allocation to users has been a burden in terms of cost for the service provider in the cellular industry. Since the spectrum can be re-used by the the service provider without degradation with use, the problems faced in the fixed channel method of spectrum allocation can be overcomed by several management techniques which allocates spectrum to users based on the demand for it, thereby eliminating the problem of spectrum waste. Also other techniques such as changing system architecture and access method can also be used. This paper avaluates the effects of dynamic spectrum allocation (DSA) in the third world countries, using Africa as a case study. It tries to compare the impact the DSA will have on the spectrum users with the fixed spectrum allocation (FSA) method currently being implemented. Furthermore, the paper delves into the cellular network growth in the African subregion and the socioeconomic impact of the mobile technology on continent. I will analyze the performance of the FSA and DSA, compare the two and suggest the best method based on their performance. I will in addition analyze the growth of cellular networks over the years using graphs and charts. I will also, show the economic impact of the mobile technology on different African countries to help in making decision on investment in the cellular industry in Africa. Finally, i will predict the growth rate of the mobile technology in ten years time using the past and current growth rate as my indices." } @INPROCEEDINGS{Adi0511:Thermal, AUTHOR="Siti Rohana Adi and Khalid {Mohamed Nor} and Wan Nor Liza {Wan Mahadi}", TITLE="Thermal Analysis of a Tubular Permanent Magnet Linear Generator Using Multiphysics Solver", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="This paper presents the thermal design aspect of linear generator. A study is carried out to investigate the temperature effects on the components in linear generator. One of the most important components in the linear generator, Neodymium iron boron (NdFeB) permanent magnet is emphasized in this study since it provides a magnetic field source for the linear generator and the influence of its electromagnetic properties towards temperature will affect the performance of linear generator. In this paper, the generator is coupled with the internal combustion engine which tends to produce heat. Due to the high temperature from the combustion engine, and the heat produced by the current carrying conductors, thermal analysis on different physical aspects has been done. In order to achieve an accurate result, the multiphysics solver is used to analyze the thermal analysis for both electrical and thermal problem. Finite element method (FEM) is used to observe this coupled field effect." } @INPROCEEDINGS{Adib0505:Fast, AUTHOR="Sasan Adibi and Mohammad Naserian and Shervin Erfani", TITLE="A Fast Handover {M-MANET} with {QoS} Support", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Looking at the progress of mobile-IP in the recent years, theres a sense that IP (for QoS support, IPv6 more specifically) is going to be involved more and more in wireless applications. The current IETF standard for mobility is the Mobile IP (RFC 3344 for IPv4 and RFC 3775 for IPv6) both work by changing the IP address when changing the subnet. Both Mobile IPv4 and IPv6 suffer from longer handover delays mainly due to AAA (authentication, authorization and accounting) signaling and IP address configuration. There are numerous proposals out there which try to either optimise Mobile IP or use different mechanisms for a certain domain. What we propose here is the use existing technologies binding to a new approach in handling QoS and smooth and technology independent handoffs, thanks to the MPLS mechanism and to the adaptive characteristics of Mobile Ad-hoc Networks (MANETs). This paper discusses a mechanism for a fast handoff in a Mobile-IP architecture. Fast handoff is destined for applications such as videoconferencing, Internet telephony, and other applications that requires minimal delays. In our proposal we suggest that the Mobile Node (MN), when away from its Home Agent (HA, in here considered as an Ingress router in the MPLS domain), visiting a Foreign Network, with the usage of multiple IPv6 connections, it actually connects to one or more (optimally two, as the Egress routers in the MPLS domain) Correspondent Nodes (CN). These CNs are actually Ad-hoc elements that are mobile inside an MPLS domain. These simultaneous connections with two CNs results adaptive handoff between CNs and when departing the MPLS domain eventually, it results a very fast and smooth handoff between neighbouring MPLS domains. This is an MPLS Mobile Ad-Hoc Network (M-MANET) topology and all the specifications of related components are valid and applicable, such as the Quality of Service (QoS) support that MPLS offers. With simulation results we discuss the overall functionality. Keywords: Ad-Hoc Networks, Mobile-IP, MPLS, IPv6, QoS, Fast Handoff" } @INPROCEEDINGS{Adib0505:IP, AUTHOR="Sasan Adibi and Shervin Erfani", TITLE="{IP-based} {IMT} Network Platform for {Mobile-IP} Applications", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="In this paper thefeasibility of IP-based IMT Network Platform for Mobile-IP networks is being discussed. Experimental systems using IP2 (IP^2) mobility management was designed and implmented in for more efficient protocol and handshake and addressing bottlenecks. The experimental system is based on a prototype implementation of IP^2 mobility management, which runs on PC servers. The validity of protocol sequence and handshake and impact of various load specifications on the system performance could be investigated through series of experiments. We have included two series of test, one of which is the feasibility tests results, it was confirmed that there was no fundamental error in IP2 mobility management and the protocol could interwork with other IP protocols. The second test was the throughput and the bottleneck tests, degradation in performance due to limitation of the transport mechanism was observed when the MN (Mobile Node) had relatively large number of active peers. Experimental results indicated that alternative mechanism to improve reliability of signalling messages was highly needed. From User-Plane viewpoint, additional processing that is specific to IP2 mobility management put negligible effect on the packet forwarding delay of the Access Router (AR). Keywords: IP, Mobility Management, IP2, Experimental" } @INPROCEEDINGS{Adib0505:Mobile, AUTHOR="Sasan Adibi and Mohammad Naserian and Shervin Erfani", TITLE="{Mobile-IP} {MPLS-based} Networks", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="The Internet backbone has been enjoying the great many advantages of Multi-Protocol Label Switching (MPLS) for quite sometimes and this employment of MPLS in wireless applications was not noticeable until the beginning of the year 2000. However researches have begun extensive efforts to extend the MPLS capability to the wireless access networks. This is aprticularly important when QoS (Quality of Service) became a major issue. In this paper we provide an overview of the MPLS-based mobile-IP management including label switched path setup, packet forwarding, and handoff/handover processing. In order to minimize the packet loss during handoff, we propose a buffer management scheme employed in both the MS (Mobile Node) and the CN (Correspondence Node). This investigation further reveals the improvement of handoff/handover procedures and depending on the structure and capacities of these buffers, traffic with variety of bandwidth requirements could be routed with minimal intrruption/packet-loss. The research also includes the integrity of peer-to-peer communications covering multi-layer communication requirements. Future work involves in investigation of buffer-system failture and its effect on the traffic-loss. This includes thorough investigation using mathemtical tools and practical investigation using proper simulation and tesbed enviornments." } @INPROCEEDINGS{Adib0505:Mobile, AUTHOR="Sasan Adibi and Shervin Erfani", TITLE="{Mobile-IP} {MPLS} {OAM} Requirements", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="This paper reflects the requirements of the Operation, Adminitration and Mainyenance of Mobile-IP MPLS-ready networks. So far variety of architectures and ideas have been proposed however there's no unified management to really investigate the integrity of these architectures and their interoperability with the pre-existing infrastructures. This is particularly crucial as transport of diverse traffic types such as voice, and data on top of Layer II traffic such as frame relay, and ATM over MPLS become more common, the ability to detect, handle and diagnose control and data plane defects becomes critical. In this paper we investigate different modules' requirements, standardization efforts, fault detection, connectivity verification and overall functionality management. This requires overall and inter-layer topology change to ensure large-scale Mobile-IP MPLS deployment could be accomplished by appropriate OAM tools to efficiently manage packet networks. This new management scheme is not only important because existing mismatches and defects may not only affect the fundamental operation of an MPLS network carrying Mobile-IP traffic, but also because they may impact SLA commitments for customers of that network. This also further opens the door to efficiently deploy QoS (Quality of Service) as a new standard way of traffic engineering and will facilitiate the cure for current gaps and mismatches." } @INPROCEEDINGS{Adib0505:Mobile, AUTHOR="Sasan Adibi and Shervin Erfani", TITLE="Mobile Ad-hoc Networks with {QoS} and {RSVP} Provisioning", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT={This paper we discuss the architecture of a QoS based Mobile Ad-hoc Network MANET using RSVP over Differentiated Services. Classical IP routing provides only a {"}best effort{"} service, which makes routing simple, however no quality of service (QoS) will be provided to applications such as streaming voice and video. For the purpose of scalability, where many connections are to be connected and treated according to the defined class for backbone networks, Differentiated Services (DiffServ) is used. In order for our system architecture to support per-flow QoS, Resource-Reservation Protocol (RSVP), DiffServ has to work hand-in-hand with RSVP. However in generalDiffServ routers do not understand RSVP messages. Independent DiffServ domains may use different IntServ-to-DiffServ mappings. We consider this mapping and the ultimate goal of this paper is to use his DiffServ-IntServ-RSVP mapping to better be utilized for the MANETs and we'll reflect the simulation results comparing MANETs with the ability of providing QoS and MANETs which don't provide such a capability.} } @INPROCEEDINGS{Adib0505:Multipath, AUTHOR="Sasan Adibi", TITLE="{MSR} Analysis in {Micro-Mobility} Networks", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Here we investigate a routing analysis for an efficient routing in a mobile-IP using ad-hoc network. This involves a mechanism that makes use of multipath approach for load balancing described in [2] and [3]. We believe that multipath load balancing technique would facilitate mobile-IP scheme with heavy multimedia applications on the run for fast handoff and handover mechanisms for minimal delay and least risk of a connectivity loss. In this proposal we make use of the existing techniques for multipath load balancing to reconstruct mobile ad-hoc networks to convey heavy traffics and use the multihomed approach to maintain connectivity with at least two point of attachment (PA) inside a cellular domain. This leads to a discussion about routing inside the cellular domain and the effect is modelled by a new mathematical and simulative framework for quantifying the overhead of reactive routing protocols such as Dynamic Source Routing (DSR) , Multipath Source Routing (MSR) and Ad hoc On-Demand Distance Vector Routing (AODV) in wireless ad hoc networks with random location of the nodes. A part of the approach talks about the MSR mechanism, which is proposed in [7], which is a weighted round-robin heuristic based forwarding and scheduling strategy among multiple routes that minimizes the mean system delivery delay. A queuing model for MSR has been established in [2], which incorporates cross-route traffic among multiple paths, and validates the RTT (Round Trip Time)-based heuristic equation in [7], where the RTT of each path is obtained by periodic probing. Keywords: Ad-Hoc Networks, Mobile-IP, IPv6, QoS, Fast Handoff, Routing Overheads, MSR, DSR" } @INPROCEEDINGS{Adik0505:H, AUTHOR="Adikari Adikari and Anil Fernando and Hemantha {Kodikara Arachchi} and Kok Keong Loo", TITLE="{H.264} Compliant Stereoscopic Video {CODEC} for Low Bit Rate Applications", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Web-enabled 3G mobile phones, with added ability to capture, transmit and display digital images/video is revolutionizing the way people live, work and recreate. The evolution of mobile communication systems shows a strong trend towards enabling mobile technology to handle all multimedia services that were previously only handled by non-mobile devices. In parallel, but quite independently to the above developments, stereoscopic [1] imaging systems that present the viewer with true 3D perception have evolved within the past decade. However, the current state of the art research and industry of this technology only concentrate on transmission over high/medium bit rate wired networks, particularly suitable for large/medium size displays in HDTV/home/Digital Cinema entertainment systems. The stereoscopic and 3D display technology used in mobile and handheld devices is limited to presenting and displaying, still stereoscopic images, either in uncompressed or monoscopically (i.e. left/right separately), compressed format. The development of effective coding techniques for this application area consists of several new challenges in having specific requirements for, limited use of bandwidth, smaller screen size and lower decoder complexity as well as being robust to mobile channel and environmental discrepancies. Within that context, the main aim of this paper is to propose a novel stereoscopic video codec based on H.264 [2] for low bit rate applications. Two stereo video sequences, Booksale and Crowd, are encoded with the proposed encoder and results are presented in. For the comparison, the same sequences are encoded with the modified MPEG-2 based stereoscopic codec and zero tree entropy based stereoscopic codec. The simulation results show that a significant PSNR gain with the proposed scheme compared to the MPEG-2 based codec and ZTE based codec for both main and auxiliary streams. Figure 1 presents the performance comparison between all three algorithms for the auxiliary streams of Booksale and Crowd sequences. It is clear that the proposed stereoscopic video codec can achieve up to 7dB and 9dB gain compared to ZTE based and MPEG-2 based stereoscopic codecs respectively." } @INPROCEEDINGS{Adin0503:Performance, AUTHOR="Abdulkareem Adinoyi and Halim Yanikomeroglu", TITLE="On the Performance of Hybrid {Macro/Microdiversity} in the {Reverse-Link} Microcellular Networks", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="We investigate the use of hybrid macro/microdiversity in the reverse-link microcellular wireless networks where low power, small and cost-effective radio access ports are linked to a central unit. We propose a new macro-selection strategy to improve the conventional macrodiversity selection technique. Furthermore, the issue of macrodiversity maximal ratio combining in non-CDMA microcellular networks is investigated as a natural extension of the soft handover of the already established CDMA cellular systems. The proposed schemes have performance advantage over the conventional macrodiversity method at a modest extra processing." } @INPROCEEDINGS{Adle0503:Optimal, AUTHOR="Micah Adler and Rakesh Kumar and Keith W. Ross and Dan Rubenstein and Torsten Suel and David. D. Yao", TITLE="Optimal Peer Selection for {P2P} Downloading and Streaming", BOOKTITLE="IEEE INFOCOM 2005", ADDRESS="Miami", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="In a P2P system, a client peer may select one or more server peers to download a specific file. In a P2P resource economy, the server peers charge the client for the downloading. A server peer's price would naturally depend on the specific object being downloaded, the duration of the download, and the rate at which the download is to occur. The optimal peer selection problem is to select, from the set of peers that have the desired object, the subset of peers and download rates that minimizes cost. In this paper we examine a number of natural peer selection problems for both P2P downloading and P2P streaming. For downloading, we obtain the optimal solution for minimizing the download delay subject to a budget constraint, as well as the corresponding Nash equilibrium. For the streaming problem, we obtain a solution that minimizes cost subject to continuous playback while allowing for one or more server peers to fail during the streaming process. The methodologies developed in this paper are applicable to a variety of P2P resource economy problems." } @INPROCEEDINGS{Adle0509:Information, AUTHOR="Andy Adler and Richard Youmaran and Sergey Loyka", TITLE="Information content of biometric features", BOOKTITLE="Biometrics Symposium 2005", DAYS=19, MONTH=sep, YEAR=2005, ABSTRACT="This paper considers the measurement of information in a biometric feature representation, based on the relative entropy measure from information theory [3]. We propose that a such a measure would permit many questions, such as the following, to be concisely addressed: ² Uniqueness of biometric features: A common question is are fingerprints really unique?. While Pankanti et al. have recently provided a sophisticated analysis of this problem based on biometric feature distributions directly, a general approach based on information content would help address this question for other biometric modalities. ² Limits to biometric template size requirements ² Feasibility of biometric encryption: Proposed biometric encryption systems use biometric data to generate keys, and thus the availability of biometric information limits the security of cryptographic key generation. ² Performance limits of biometric matchers: While some algorithms outperform others, it clear that there are ultimate limits to error rates, based on the information available in the biometric features. ² Privacy protection: It would be useful to quantify the threat to privacy posed by the release of biometric information, and also to be able to quantify the value of technologies to preserve privacy, such as algorithms to de-identify face images." } @INPROCEEDINGS{Adus0506:KTDCKM, AUTHOR="Pratima Adusumilli and Xukai Zou", TITLE="{KTDCKM-SDC:} A Distributed Conference Key Management Scheme for Secure Dynamic Conferencing", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="Secure Dynamic conferencing (SDC) is a scenario where given a group of participants, any subset of participants can form a privileged subgroup, called a conference, and communicate securely among themselves. The existing SDC schemes belong to two classes: centralized and distributed. The former incurs the single-point of failure, the central point of attack and performance bottleneck. The two existing distributed dynamic conferencing schemes, which are based on public key cryptosystems, are inefficient and imply that anyone, as long as having a pair of public and private keys, can be in the group, thus, lacking the concept of group and the group membership management. In this paper, we propose a new distributed dynamic conferencing scheme which is based on the well-known key tree scheme. The new scheme enforces group membership management and surpasses all the existing SDC schemes in terms of simplicity, efficiency and scalability." } @INPROCEEDINGS{Afkh0506:Joint, AUTHOR="Kaywan Afkhamie and Haniph Latchman and Larry Yonge and Timothy Davidson and Richard Newman", TITLE="Joint Optimization of Transmit Pulse Shaping, Guard Interval length, and receiver side narrow-band interference mitigation in the {HomePlugAV} {OFDM} system", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="The primary subject of this paper is the selection of a pulse-shaping waveform for in-home power line communications. As system performance is also determined by other parameters affecting the length and shaping of the OFDM symbol, the problem formulation is expanded to also include the simultaneous selection of guard interval length and Hanning window length, creating a joint optimization problem. Given the constraints of allowing no transmit notch filters, and adequate receive side mitigation of narrow band jammers, we jointly optimize the selection of guard interval length, transmit pulse-shaping and receive side windowing for throughput performance on the average power line channel. Throughput performance is inferred from SNR data and associated guard interval overhead. We also present results of performance assessment and parameter selection, for the average power line channel, based on a collection of 120 measured power line channel impulse responses." } @INPROCEEDINGS{Afsh0505:Approach, AUTHOR="S. Afshar and Mahmud Fotuhi-Firuzabad", TITLE="An approach to Reliability Evaluation of {HVDC} Systems", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="An approach is presented in this paper to determine the reliability evaluation of HVDC systems. A contingency enumeration approach is presented based on a fault tree analysis. A few simple analysis are introduced for determining reliability of HVDC interlinked and transmission systems. A number of reliability indices recommended by CIGRE are calculated for the test systems. The research summarized in this paper will extend the techniques for reliability evaluation of HVDC systems primarily in the development of a network flow analysis technique. The proposed technique is capable of efficiently detecting isolated subsystems, their effects on other subsystems, and the system capacity. Moreover extensions will be made in modeling of components with spares, and outage enumeration." } @INPROCEEDINGS{Agah0505:Preventing, AUTHOR="Afrand Agah", TITLE="Preventing {DoS} attack in Sensor and Actor Networks: A Game Theoretic Approach", BOOKTITLE="ICC 2005 Wireless Networking", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="Wireless sensor and actor networks are a group of sensors and actors linked by wireless medium to perform sensing and acting tasks. In such networks, sensors gather information and actors perform appropriate actions. In order to perform right and timely actions, sensor data must be valid. Insufficiency of memory and battery power of sensors makes the security of sensor networks a hard task to do. This insufficiency also makes applying the existing methods of securing other type of networks on the sensor networks unsuitable. A malicious node is able to drop incoming packets or issue route error messages to misdirect the path, where both of these efforts are known as types of denial of service attack. In order to isolate malicious nodes in wireless sensor and actor networks and provide a secure routing, we formulate attack-defense problem as a two-player, nonzero-sum, non-cooperative game between an attacker and a wireless sensor and actor network. We show that this game achieves Nash equilibrium and thus leading to a defense strategy for the network. In this paper we propose two novel schemes for preventing denial of service attack. First approach is called Utility based Dynamic Source Routing (UDSR), which is a fortified version of Dynamic Source routing (DSR). It incorporates the total utility of each route in data packets, where utility is a value that we are trying to maximize in the game theoretic approach. Second approach is based on a watch-list, where each node earns a rating from its neighbors, based on its previous cooperation in the network. We present a performance analysis of DSR and compare it with UDSR and watch-list approach. Results show that the proposed game frameworks significantly increase the chance of success in defense strategy for the wireless sensor and actor networks." } @INPROCEEDINGS{Agah0511:Enforcing, AUTHOR="Afrand Agah and Kalyan Basu and Sajal Das", TITLE="Enforcing Security for prevention of {DoS} Attack in Wireless Sensor Networks using Economical Modeling", BOOKTITLE="2nd IEEE International Conference on Mobile Ad-Hoc and Sensor Systems", DAYS=7, MONTH=nov, YEAR=2005, ABSTRACT="This paper focuses on the assessment of the properties of security enforcement mechanisms for prevention of denial of service (DoS) attacks in wireless sensor networks. In the first part, we demonstrate the requirement for security enforcement mechanism using auction theory that allows us to detect non cooperative nodes. In the proposed protocol, nodes prefer to participate in forwarding incoming packets and gaining reputation in the network. Nodes willing to do so must compete against each other. The competition is based on auction theory. The amount of a bid that each node offers is equal to its utility value; and the price that a winner of a bid pays is a reduction of its original power. Node's truthful bidding remains a dominant strategy and so to prevent DoS attack, nodes who do not bid truthfully, should be isolated. We also formulate attack-defense problem as a non-cooperative two-player, nonzero-sum game between an attacker and a wireless sensor network. We show that this game achieves Nash equilibrium and thus leading to a defense strategy for the network. Two approaches are proposed, the first one is called Utility based Dynamic Source Routing (UDSR). It incorporates the total utility of each route in data packets, where utility is a value that we are trying to maximize in the game theoretic approach. The second approach is based on a watch-list, where each node earns a rating from its neighbors, based on its previous cooperation in the network. Results show that the proposed game frameworks significantly increase the chance of success in defense strategy for the wireless sensor network." } @INPROCEEDINGS{Agam0505:Sliding, AUTHOR="Mohammed Agamy", TITLE="Sliding Mode Control of Induction Motors with Minimized Control Effort: A Comparative Study", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Field oriented control has proven to be one of the most effective methods to control the induction motor (I.M). This technique has the merit of decoupling the torque the flux dynamics and thus, the induction motor can be treated in the same as a dc machine. However, this method is very sensitive to external load disturbances and motor parameter variations. Variable structure control is a well known robust control technique. Therefore, a sliding mode controller was introduced to the field oriented control system in order to avoid the aforementioned drawbacks of the field oriented control system. But in sliding mode control the upper bound of uncertainties must be known to properly adjust the controller parameters. Since these uncertainties are practically difficult to obtain, they must be estimated during the system operation. Therefore, a fuzzy inference mechanism was proposed here to continuously compensate for the parameter uncertainties. An adaptation law is also proposed to minimize the required control effort. This paper presents a comparative evaluation of a new adaptive fuzzy sliding mode controller used for speed and flux regulation for an induction motor drive system as compared to classical control methods. The proposed controller has the merits of sliding mode control: fast response, robustness to plant parameter variations and simplicity of implementation and it also avoids the problems of chattering and the need of a large control effort achieve the control objective by means of using and optimization technique to vary the gains of the sliding mode controller according to the position of the operating point on the state trajectory. The proposed controller is compared to conventional PI, conventional sliding mode and fuzzy sliding mode control. The results for a 5HP, 3-phase, 220V I.M show a much lower control effort compared to classical sliding mode methods and parameter insensitivity compared to the PI controller." } @INPROCEEDINGS{Agar0503:Towards, AUTHOR="Sharad Agarwal and Antonio Nucci and Supratik Bhattacharyya", TITLE="Towards {Internet-Wide} Network Management", BOOKTITLE="IEEE INFOCOM 2005 Poster/Demo session", ADDRESS="Miami, FL, USA", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="Today, network management is an ad-hoc process. Intradomain TE is performed by each AS in isolation. Interdomain TE is not well understood. There is an assumption of complete separation between intradomain and interdomain routing and between ASes during TE. However, hot potato shifts during TE can cause significant variation. We show the extent of this variation based on data from an operational network and show the impact on a neighboring AS. We argue that coordinated network management is an open topic that needs further exploration." } @INPROCEEDINGS{Agar0505:Rapidly, AUTHOR="Nainesh Agarwal", TITLE="Rapidly Prototyping {DSP} Extensions Using {CoDeL:} The {DWT} Using Lifting", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="In this report, we present CoDel (Controller Description Language), a rapid hardware prototyping language, which is an effective platform for quickly developing DSP extensions. CoDeL is similar to the C programming language and is therefore easy to learn. However, unlike other C-like languages such as SystemC and Verilog that require explicit architecture definition, CoDeL targets the specification and design at the behavioral level. It is a procedural language in which the order of the statements implicitly represents the sequence of activities. It extracts the data and control flow from the program automatically, assigns the necessary hardware blocks and exploits inherent parallelism. CoDeL introduces the concept of object-oriented hardware design and provides primitives, data structures and constructs for manipulating objects at the behavioral/RTL level. It includes a library of I/O protocols that simplify (sub)system interaction. The CoDeL compiler produces synthesizable VHDL code which can be targeted to any technology including PLD, FPGA or ASIC. As an example, we implement modules which collectively perform the biorthogonal one-dimensional discrete wavelet transform using the lifting technique. Specifically, we implement the wavelet transform using the Le Gall integer-to-integer 5/3 filter bank. This is one of the wavelets used in the JPEG2000 image compression specification. Using CoDeL, we successfully show how the 5/3 wavelet transform can be implemented quickly and efficiently with just a few lines of code." } @INPROCEEDINGS{Agar0506:Lightweight, AUTHOR="Sandip Agarwala and Greg Eisenhauer and Karsten Schwan", TITLE="Lightweight Morphing Support for Evolving Middleware Data Exchanges in Distributed Applications", BOOKTITLE="The 25th International Conference on Distributed Computing Systems", ADDRESS="Columbus, Ohio, USA", DAYS=6, MONTH=jun, YEAR=2005, ABSTRACT="Most systems must evolve as their missions or roles change and as they are required to adapt to new conditions. When evolving large distributed applications, it is particularly difficult to make changes to the data formats that underlie their components' communications, because such `format evolution' can affect all or many application components. Prior approaches to the problem of implementing changes in the communications of a deployed system have relied upon ad-hoc solutions or protocol negotiation to avoid message format mismatches. Unfortunately, such solutions tend to increase the complexity of application code. This paper presents a novel approach to the problem of data format evolution that combines meta-data about the data being exchanged with dynamic binary code generation to create a robust messaging system that naturally supports application evolution. The idea is to specialize the communications of application components by dynamically generating the code that can automatically transform incoming data into forms that receiving components can understand. A realistic example in the context of publish/subscribe middleware is used to illustrate how this technique can be applied to enhance interoperability between different version of distributed applications." } @INPROCEEDINGS{Agar0511:Experimental, AUTHOR="Avesh Agarwal and Wenye Wang", TITLE="An Experimental Study of {Cross-Layer} Security Protocols in Public Access Wireless Networks", BOOKTITLE="Globecom 2005 Computer \& Network Security", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="Wireless networks are prone to malicious attacks because of their unique characteristics such as shared air medium and ease of connectivity. Therefore, provisioning security in wireless networks is very essential, but security effects system performance, and therefore impacts quality of service (QoS) of communication. Previous studies on security protocols are mainly focused on improving cryptographic aspects. However, there is lack of quantitative results demonstrating the impact of security on the system performance which can be affected dramatically by applying security policies in combination with mobile environment. Therefore, we conduct an experimental study on a wireless IP testbed with security at different layers and their impact on different types of data streams such as TCP and UDP with regard to delay and throughput. In this paper, we present a detailed study of performance overhead caused by the most widely used security protocols such as WEP, IPSEC, 802.1x with RADIUS, and SSL." } @INPROCEEDINGS{Agar0512:Impact, AUTHOR="Saurabh Agarwal and Rahul Garg and Nisheeth Vishnoi", TITLE="The Impact of Noise on the Scaling of Collectives: A Theoretical Approach", BOOKTITLE="12th Annual IEEE International Conference on High Performance Computing", ADDRESS="Goa, India", DAYS=18, MONTH=dec, YEAR=2005, ABSTRACT="The performance of parallel applications running on large clusters is known to degrade due to the interference of kernel and daemon activities on individual nodes, often referred to as noise. In this paper, we focus on an important class of parallel applications, which repeatedly perform computation followed by a collective operation such as a barrier. We model this theoretically and demonstrate, in a rigorous way, the effect of noise on the scalability of such applications. We study three natural and important classes of noise distributions: the exponential distribution, the heavy-tailed distribution (captured by the Pareto distribution) and the Bernoulli distribution. We show that the systems scale well in the presence of exponential noise, but the performance goes down drastically in the presence of heavy-tailed of Bernoulli noise. The main contribution of this paper is to initiate the study of the impact of noise on the scaling of parallel applications in a formal manner. We believe that this study will prove to be extremely useful in identifying and improving the bottlenecks in the scalability of systems in a more systematic way, for instance, by designing scheduling policies, which take into account the nature of the noise to improve the overall system performance." } @INPROCEEDINGS{Agat0505:Self, AUTHOR="Doros Agathangelou and Benny Lo and Jeffrey Wang and Guangzhong Yang", TITLE="{Self-Configuring} {Video-Sensor} Networks", BOOKTITLE="Pervasive 2005, Short Papers/Demos/Videos", DAYS=8, MONTH=may, YEAR=2005, ABSTRACT="A growing demand on healthcare providers worldwide is the provision of long-term care for the elderly. Instead of relying on nursing homes, a better way to maintain and improve their well being is to provide managed care in their own dwellings. The use of video based sensing provides an effective means of detecting changes in activity, gait and posture but the installation and calibration of the sensors are major obstacles to overcome in practical applica-tions. This paper presents a novel MDS (Multidimensional Scaling) based self-configuration technique for video sensor networks. It allows implicit estimation of the geometrical locations of the sensors and permits the optimal usage of re-sources under a distributed processing environment." } @INPROCEEDINGS{Agba0506:Application, AUTHOR="Adnan Agbaria", TITLE="{Application-Driven} {Coordination-Free} Distributed Checkpointing", BOOKTITLE="The 25th International Conference on Distributed Computing Systems", ADDRESS="Columbus, Ohio, USA", DAYS=6, MONTH=jun, YEAR=2005, ABSTRACT="Distributed checkpointing is an important concept for providing fault tolerance in distributed systems. In today's applications, e.g., grid and massively parallel applications, the imposed overhead of taking a distributed checkpointing using the known approaches could outweigh its benefits due to coordination and other overhead among the processes. This paper presents an innovative approach for distributed checkpointing. In this approach, the checkpoints are obtained using offline analysis based on the application level. During execution, coordination is not required at all. After presenting our approach, we prove safety and present performance analysis using stochastic models." } @INPROCEEDINGS{Agga0505:Convex, AUTHOR="Alok Aggarwal and Teresa H. Meng", TITLE="A Convex {Interior-Point} Method for Optimal {OFDM} {PAR} Reduction", BOOKTITLE="ICC 2005 Signal Processing for Communications", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="The main disadvantage of OFDM is the high time-domain peak-to-average power ratio (PAR) that limits transmitter power efficiency. This paper presents a convex optimization algorithm for minimizing the PAR of an OFDM signal subject to constraints on the constellation error vector magnitude (EVM). The derivation reduces computational complexity by exploiting known features of the optimization problem, such as OFDM's FFT structure. Simulation results are given for the 802.11a/g WLAN standard. The algorithm achieves PAR within 1 dB of the globally optimal solution after two iterations. The main complexity per iteration is four FFTs plus the solution of a linear system of equations. The customized algorithm is approximately 100 times faster than a general-purpose optimizer." } @INPROCEEDINGS{Agga0510:Fairness, AUTHOR="Sudhir Aggarwal and Hemant Banavar and Sarit Mukherjee and Sampath Rangarajan", TITLE="Fairness in {Dead-Reckoning} based Distributed {Multi-Player} Games", BOOKTITLE="NetGames 2005", DAYS=10, MONTH=oct, YEAR=2005, ABSTRACT="In a distributed multi-player game that uses dead-reckoning vectors to exchange movement information among players, there is inaccuracy in rendering the objects at the receiver due to network delay between the sender and the receiver. The object is placed at the receiver at the position indicated by the dead-reckoning vector, but by that time, the real position could have changed considerably at the sender. This inaccuracy would be tolerable if it is consistent among all players; that is, at the same physical time, all players see inaccurate (with respect to the real position of the object) but the same position and trajectory for an object. But due to varying network delays between the sender and different receivers, the inaccuracy is different at different players as well. This leads to unfairness in game playing. In this paper, we first introduce an ``error'' measure for estimating this inaccuracy. Then we develop an algorithm for scheduling the sending of dead-reckoning vectors at a sender that strives to make this error equal at different receivers over time. This algorithm makes the game very fair at the expense of increasing the overall mean error of all players. To mitigate this effect, we propose a budget based algorithm that provides improved fairness without increasing the mean error thereby maintaining the accuracy of game playing. We have implemented both the scheduling algorithm and the budget based algorithm as part of BZFlag, a popular distributed multi-player game. We show through experiments that these algorithms provide fairness among players in spite of widely varying network delays. An additional property of the proposed algorithms is that they require less number of DRs to be exchanged (compared to the current implementation of BZflag) to achieve the same level of accuracy in game playing." } @INPROCEEDINGS{Agha0505:Application, AUTHOR="Farshid Agharebparast and Victor Leung", TITLE="Application of the {Legendre/Fenchel} Transforms in the Analysis of Wireless Networks Using Network Calculus", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Throughout the last decade, a sophisticated theory emerged and has been developed to model and evaluate communication networks and queuing systems based on min-plus (or equivalently max-plus) algebra. The two main characteristics of this theory, so-called (/sigma, /rho)-calculus or Network Calculus [1], are its traffic characterization based on arrival envelopes and a filtering theory based on a specialized convolution operator. In this paper, the development of a tool for simplification of network calculus based performance analysis of wireless networks by applying a frequency-domain like analysis is presented. Similar to the application of Fourier transform in the conventional system theory, The Legendre and Fenchel transforms map functions from their min-plus forms into another domain, changing a convolution in the min-plus domain to a normal addition in the transformed domain. Legendre transform has been previously introduced in [2] in modeling a simple queueing system and for system identification. The limitations of these transforms are that they are mainly applicable to convex/concave functions [3] (otherwise set-valued) and are defined to be used in time-invariant systems. In this paper, we first compare the two transforms, and present modifications and strategies that allow us to apply them in modeling networks incorporating wireless links. The proposed scheme is more elaborated by an example in modeling multimedia streaming to a wireless user. The paper is then concluded with a system identification application." } @INPROCEEDINGS{Agha0505:Modeling, AUTHOR="Farshid Agharebparast and Victor Leung", TITLE="Modeling Wireless Link Layer by Network Calculus for Efficient Evaluations of Multimedia Quality of Service", BOOKTITLE="ICC 2005 Multimedia Communication and Home Networking", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="In this paper, a methodology for quality of service (QoS) evaluations of wireless networks based on Network Calculus (NC) models is introduced. The proposed model employs modular concatenation of selected NC components to represent the effect of wireless links on the observed QoS performance from a link-layer viewpoint. We present a mathematical analysis that applies the model to evaluate the performance of a wireless video streaming application, by deriving estimates of the playback delay and buffer size at the receiver side. Owing to the analytical strength of NC, the model offers an efficient way of deriving end-to-end QoS characteristics in wireless networks." } @INPROCEEDINGS{Agra0503:Energy, AUTHOR="Neha Jain and Ratnabali Biswas and Nagesh Nandiraju and Dharma Agrawal", TITLE="Energy Aware Routing for Spatio-temporal Queries in Sensor Networks", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="Wireless sensor networks is an emerging technology that can significantly improve the quality of spatio-temporal data monitoring because of their untethered operation and potential for large scale deployment. In this paper, we define a communication architecture that supports distributed query processing to evaluate spatio-temporal queries within the network. We represent these queries by query trees and distribute query operators to appropriate sensor nodes. As operator execution demands high computation capability, we propose use of a heterogenous sensor network where query operators are assigned to sparsely deployed resource-rich nodes within a dense network of low power sensor nodes. We design an adaptive, decentralized, low communication overhead algorithm to determine an operator placement on the resource-rich nodes in the network to minimize cost of transmitting data along a routing tree constructed to continuously retrieve data at the sink, from a set of spatially distributed geographical regions. To the best of our knowledge, this is the first attempt to build an energy aware routing infrastructure to enable in-network processing of spatio-temporal queries." } @INPROCEEDINGS{Agra0503:Optimal, AUTHOR="Dharma Agrawal and Wei Li", TITLE="On Optimal Admission Threshold for {CDMA} Systems supporting Integrated Services", BOOKTITLE="IEEE INFOCOM 2005 Poster/Demo session", ADDRESS="Miami, FL, USA", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="In code-division multiple-access (CDMA) systems, the reverse link capacity is limited by the total received power at each base station. The admission threshold is critical to the performance of call admission control (CAC) based on the total received power. We analyze the optimal threshold for CDMA systems supporting integrated voice and data services with the purpose of maximizing system capacity. We demonstrate that the cell capacity can be power limited or interference limited, which is greatly affected by the inter-cell interference. A CAC with adaptive threshold is proposed." } @INPROCEEDINGS{Agra0505:Controlling, AUTHOR="Banit Agrawal and Nitin Kumar and Mart Molle", TITLE="Controlling Spam Emails at the Routers", BOOKTITLE="ICC 2005 Next Generation Networks for Universal Services", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="Like it or not, unsolicited bulk commercial email (aka ``spam'') has become a regular menu item on the Internet information diet. Every day, millions of people find their email in-boxes clogged with vast quantities of spam. Moreover, the daily replenishment of all those in-boxes with new spam also consumes significant amount of network bandwidth. Dealing with spam is like fighting a battle against a large army; the most effective approach is to employ multiple tactics. However, almost all spam control methods that have been proposed and implemented follow the same basic theme of establishing a ``front line'' of defense at the end-user level. Thus, in this paper we propose a method for blocking the supply lines. More specifically, we identify spam at the router level and control it via rate limiting. Spam identification is done in two phases. In the first phase, we identify the bulk stream of email messages and in second phase we apply Bayesian classifier to identify whether it is a spam. If a bulk email stream is classified as a spam then we rate limit it (e.g no more than one copy per minute). We provide a mechanism to inform the end-user of spam emails identified at the router. Our proposed method exploits the short timespan delivery and bulkiness of spam emails. We use publicly available spam corpus to evaluate our proposed schemes and in the other set of experiments, we work on one month log of our department emails to provide the representative results." } @INPROCEEDINGS{Agra0505:Integrated, AUTHOR="Deepak Agrawal and Nelson {L. S. da Fonseca} and Fabrizio Granelli", TITLE="Integrated {ARM/AQM} Mechanisms Based on {PID} Controllers", BOOKTITLE="ICC 2005 Communications QoS, Reliability and Performance Modeling", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="This paper presents integrated mechanisms for differentiated service (DiffServ) architecture consisting of active rate management (ARM) at the edges of the network and two color Active Queue Management (AQM) controllers at the core of the network. AQM controller is a robust linear quadratic regulator based PID controller for two colors marking at the core. The proposed mechanism is for DiffServ assured forwarding per hop behavior for guaranteeing minimum rates. The performance of proposed architecture is compared via simulation using the NS-2 simulator." } @INPROCEEDINGS{Agua0509:Railway, AUTHOR="Marina Aguado and Eduardo Jacob and Purificación Saiz and Juan José Unzilla and Maria Victoria Higuero and Jon {Matías}", TITLE="Railway Signaling Systems and New Trends in Wireless Data Communication", BOOKTITLE="VTC'F05 Intelligent Transportation System", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="With the increment of passenger railway traffic, especially in high speed lines, improvements in railway transportation safety become imperative. The integration of new wireless communication technologies will provide train control centers communication systems with larger bandwidth. This will enable the use of new services and functions, and so increasing safety in the overall system, as well as line capacity. Images transmission of undesired or risky situations; transmission of a great amount of data generating time history and making possible to identify risky tendencies; the golden run (a train optimal operation for a given line); etc.. are examples of some of these services. In order to meet these new demands: mobile, low latency and broadband applications, new communication technologies, 802.11b, 802.11p, MBWA must be considered." } @INPROCEEDINGS{Agui0504:Channel, AUTHOR="Ana Aguiar and Adam Wolisz and Horst Lederer and Holger Karl", TITLE="{Channel-Adaptive} Schedulers with {State-of-the-Art} Channel", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="In this paper we study the effects of using state-of-the-art channel predictors with two channel-aware schedulers: a channel-aware round robin, and the proportional fair scheduler. We evaluate the performance for the case when the scheduler queues are always full and for the case when this does not happens. The round robin scheduler proves to be only marginally influenced by the inaccurate predictor in both cases. The proportional fair scheduler, however, can become very unfair when few wireless terminals have data to be scheduled, some of them have a very good channel and the channel prediction is slightly inaccurate. When the queues are not full, however, this behaviour is no longer a problem. But, in this case, there seems to be little to win by the use of a complex scheduler; a one-step predictor achieves similar performance." } @INPROCEEDINGS{Agui0509:Erasure, AUTHOR="Marcos Aguilera and Ramaprabhu Janakiraman and Lihao Xu", TITLE="On the Erasure Recoverability of {MDS} Codes under Concurrent Updates", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="We consider a fault-tolerant distributed storage system that protects data on k disks using a systematic linear (n, k) MDS code. In such a system, updates to data blocks require corresponding updates to check blocks. Concurrent fault-prone access by multiple writers can drive the system into an inconsistent state with reduced tolerance for disk failures. We show tight bounds on the erasure recoverability of an (n, k) MDS code in this scenario. The bounds depend not just on the minimum distance of the code, but also on the maximum number of concurrent faulty writers and the manner in which they attempt to update the check blocks (one at a time/all at once.)" } @INPROCEEDINGS{Agus0509:AWGN, AUTHOR="Edson Agustini and Sueli Costa", TITLE={{{"}AWGN{"}-Signal} Transmition in Hyperbolic Spaces}, BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="We introduce and discuss the concept of Gaussian probability density function for the n-dimensional hyperbolic space which has been proposed as an environment for coding and decoding signals. An upper bound for the error probability of signal transmission associated with the hyperbolic distance is established. The pdf and the upper bound were developed using the Poincaré models for the hyperbolic spaces." } @INPROCEEDINGS{Agye0506:Detecting, AUTHOR="Malik Agyemang", TITLE="Detecting Web Content Outliers from Web Documents", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="Outlier mining is dedicated to finding data objects with significantly different characteristics from the rest of the data objects. Outlier mining has been extensively studied in statistics and recently data mining. However, exploring the web for outliers has received almost no attention in the data mining community. Web content outliers are web documents with varying contents compared to similar documents within the same category. Mining web content outliers may lead to the identification of competitors in electronic commerce and improved results from web search engines. This paper explores the advantages of n-gram systems for partial matching of strings and proposes WCOND-Mine algorithm for mining web content outliers. Experimental results using planted motifs indicate that WCOND-Mine is capable of finding web content outliers from web documents." } @INPROCEEDINGS{Ahir0509:Tradeoff, AUTHOR="Vijay Ahirwar and B. Sundar Rajan", TITLE="Tradeoff between {PAPR} Reduction and Decoding Complexity in Transformed {OFDM} Systems", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="It is known that in a OFDM system using Hadamard transform or phase alteration before the IDFT operation can reduce the Peak-to-Average Power Ratio (PAPR). Both these techniques can be viewed as constellation precoding for PAPR reduction. In general, using non-diagonal transforms, like Hadamard transform, increases the ML decoding complexity. In this paper we propose the use of block-DFT matrices and show that appropriate block-DFT matrices give lower PAPR as well as lower decoding complexity compared to using Hadamard transform. Moreover, we present a detailed study of the tradeoff between PAPR reduction and the ML decoding complexity when using block-DFT matrices with various sizes of the blocks." } @INPROCEEDINGS{Ahlg0509:Ambient, AUTHOR="Bengt Ahlgren and Lars Eggert and Börje Ohlman and Andreas Schieder", TITLE="Ambient Networks: Bridging Heterogeneous Network Domains {(INVITED} {PAPER)}", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="Providing end-to-end communication in heterogeneous internetworking environments is a challenge. Two fundamental problems are bridging between different internetworking technologies and hiding of network complexity and differences from both applications and application developers. This paper presents abstraction and naming mechanisms that address these challenges in the Ambient Networks project. Connectivity abstractions hide the differences of heterogeneous internetworking technologies and enable applications to operate across them. A common naming framework enables end-to-end communication across otherwise independent internetworks and supports advanced networking capabilities, such as indirection or delegation, through dynamic bindings between named entities." } @INPROCEEDINGS{Ahlg0509:Names, AUTHOR="Bengt Ahlgren and Lars Eggert and Börje Ohlman and Jarno Rajahalme and Andreas Schieder", TITLE="Names, Addresses and Identities in Ambient Networks", BOOKTITLE="First International ACM Workshop on Dynamic Interconnection of Networks 2005", ADDRESS="Cologne, Germany", DAYS=2, MONTH=sep, YEAR=2005, ABSTRACT="Ambient Networks interconnect independent realms that may use different local network technologies and may belong to different administrative or legal entities. At the core of these advanced internetworking concepts is a flexible naming architecture based on dynamic indirections between names, addresses and identities. This paper gives an overview of the connectivity abstractions of Ambient Networks and then describes its naming architecture in detail, comparing and contrasting them to other related next-generation network architectures." } @INPROCEEDINGS{Ahlu0502:Running, AUTHOR="Christer Ahlund", TITLE="Running Variance Metric for evaluating performance of Wireless {IP} Networks in the {MobileCity} Testbed", BOOKTITLE="Testbeds and Research Infrastructures for the DEvelopment of NeTworks and COMmunities", ADDRESS="Trento (Italy)", DAYS=21, MONTH=feb, YEAR=2005, ABSTRACT="Performance measurements of wireless local area networks are a challenging task. This paper proposes and analyzes a Running Variance Metric and its formal aspects. An approach to evaluate the performance of wireless local-area networks, in infrastructure mode as well as in ad-hoc mode is discussed. The Running Variance Metric is used to discover relative loads of available access-points/gateways at the network layer, in order to provide connectivity to the wired network. The paper discusses a simulation study. The simulation results demonstrate the usefulness and efficiency of the Running Variance Metric to evaluate the utilization of available access-points/gateways. It is also shown that this metric can be used for hop-analysis in multi-hop ad hoc wireless networks. Its usability with Mobile IP is discussed." } @INPROCEEDINGS{Ahlu0509:Model, AUTHOR="Jaswinder Ahluwalia and Ingolf Krueger and Michael Meisinger and Walter Philipps", TITLE="{Model-Based} {Run-Time} Monitoring of {End-to-End} Deadlines", BOOKTITLE="EMSOFT 2005", ADDRESS="Jersey City Hyatt, Jersey City NJ", DAYS=18, MONTH=sep, YEAR=2005, ABSTRACT="The correct interplay among components in a distributed, reactive system is a crucial development task, particularly for embedded systems such as those in the automotive domain. Model-based development is suggested as a means for capturing key structural and behavioral requirements before implementing code. Current development approaches focus on components as the central development entity, leaving component integration as a separate and error-prone task. This approach is particularly problematic in the area of Quality-of-Service (performance and throughput) properties that are inherently end-to-end. We address this problem by using a model where system functions, not components implementing them, are central from the early phases of requirements capture through implementation. We develop a domain model for system functions (or services) based on interaction patterns; this model allows deadline specifications ranging from individual messages to entire scenarios. Using a combination of modeling tools and code-generators for the RT~CORBA platform, we provide an experimentation platform for monitoring these specified deadlines in executable specifications." } @INPROCEEDINGS{Ahma0505:Design, AUTHOR="Ali Ahmadi and Raveendra Rao", TITLE="Design of {Space-Time} Trellis Codes with Multi-h {CPM} Signals", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Signal design for wireless data links modeled as quasi-static Rayleigh is approached using Space-Time Trellis (STT) coding and power/bandwidth efficient multi-h phase- coded Continuous Phase Modulation (CPM) signals. System configuration for achieving multiple-input multiple-output (MIMO) with arbitrary number antennas at the transmitter and receiver is described and several examples are given. At the receiver, the received signal is modeled as a linear sum of Rayleigh faded multi-h CPM signals with Additive White Gaussian Noise (AWGN). The problem of recovering transmitted data from such a composite signal is addressed using the criterion of Maximum Likelihood Sequence Estimation (MLSE). The finite-state discrete-time properties of the received composite signal are exploited and using Euclidean distance criterion best STT codes are determined. Performance analysis is presented based on pair-wise error probabilities (PWEP) for all possible pairs of signals in signal-space. It is noted that PWEP is a function of signal matrix, and hence on multi-h CPM, channel gain matrix. The signal matrix corresponding to error events is presented as a function of multi-h CPM signal parameters. From this signal matrix, the rank and the minimum determinant (minimum product of eigenvalues) of STT coded multi-h CPM can be found. It is shown that for these STT codes coding gain of 4.5 dB can be achieved relative to identical coding with MSK." } @INPROCEEDINGS{Ahma0505:Efficient, AUTHOR="Javad Ahmadi-Shokouh", TITLE="Efficient Constitution of a {Vector-Hydrophone} for Finite {Estimation-Variance} in {Direction-Finding} Away from any Reflecting Boundary", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="An underwater acoustic vector-hydrophone is composed of two or three spatially collocated but orthogonally oriented velocity-hydrophones, plus an optional collocated pressure-hydrophone. An efficient vector-hydrophone constitution is identified for finite-variance direction-finding away from any reflecting boundary. This is achieved by to be non-singular identifying the necessary and sufficient vector-hydrophone composition configuration for the Fisher Information Matrices. The results show that the x-axis plus the yaxis velocity-hydrophones alone are sufficient for direction-finding of incident signal except two singular directions which are parallel and perpendicular to reflecting boundary." } @INPROCEEDINGS{Ahma0505:Self, AUTHOR="Javad Ahmadi-Shokouh and Hengameh Keshavarz", TITLE="{Self-Similarity} Assessment in {Variable-Bit-Rate} Video Traffic Using the {Largest-Lyapunov-Exponent}", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Performance assessments of broadband high-speed networking technologies require adequate statistical models of video traffic which it is recently a major part of many telecommunications services. Due to bandwidth restrictions, video data are usually compressed using the modern effective coding standards like MPEG. Since video data may be produced from different sources (e.g. talk/news, movie and soccer), these data have a variable-bit-rate (VBR) nature. Hence, to determine an appropriate bandwidth in digital communication network implementation and/or to design an adequate structure for video source modeling, the video data need to be assessed in terms of being chaotic. In this paper, the Largest-Lyapunov-Exponent (LLE) is employed to evaluate the VBR video data. In this evaluation different kinds of real videos are first compressed via an MPEG encoder. The time series data of the compressed video frames are then assessed by LLE in terms of self-similarity. The results classify the video types and propose how to choose the model degree upon the video data type." } @INPROCEEDINGS{Ahma0505:Vector, AUTHOR="Javad Ahmadi-Shokouh and Hengameh Keshavarz", TITLE="A {Vector-Hydrophone's} Minimal Composition for Finite {Estimation-Variance} in {Direction-Finding} Near a {Rigid-Boundary}", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="An underwater acoustic vector-hydrophone is composed of two or three spatially collocated but orthogonally oriented velocity-hydrophones, plus an optional collocated pressure-hydrophone. A minimum vector-hydrophone configuration is identified for finite-variance direction-finding near a rigidboundary. This is achieved by identifying the necessary and sufficient vector-hydrophone composition configuration for the Fisher Information Matrices to be non-singular." } @INPROCEEDINGS{Ahma0510:Adaptive, AUTHOR="Imran Ahmad", TITLE="An Adaptive High Performance Architecture for Processable Bulk Data Transfers on a Grid", BOOKTITLE="2nd International Workshop on Networks for Grid", DAYS=3, MONTH=oct, YEAR=2005, ABSTRACT="For resource intensive tasks, effective utilization of resources is essential to achieve scalability and a satisfactory quality of service. The number of resources required and how the resources should be grouped depends on many factors, such as, network delays, the availability of resources and their current utilizations. Making such decisions at runtime using information, such as, current system state can improve performance. This paper proposes such adaptive architecture in which resource groupings can be changed dynamically based on the task to be performed and the system state. A prototype implementation, valid for a certain type of tasks, is described. This architecture can be extended for other types of tasks using the concepts discussed in this paper." } @INPROCEEDINGS{Ahma0511:Information, AUTHOR="Atif Ahmad and Ruighaver", TITLE="An {Information-Centric} Approach to Data Security in Organizations", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="Many organizations focus on a computing-centric approach to information security whilst neglecting the security of information on paper and amongst personnel. This paper presents a model that is both media-independent and information-centric, allowing organizations to pursue an integrated methodology towards analysing risks and providing information protection across all types of media. Using this model to map information flows within business and knowledge processes will quickly show that it will be almost impossible to control all risks, but the resulting detailed risk profile may enable the organization to explore alternative processes with lower risks." } @INPROCEEDINGS{Ahma0511:Preemption, AUTHOR="Iftekhar Ahmad", TITLE="{Preemption-Aware} Routing for {QoS-Enabled} Networks", BOOKTITLE="Globecom 2005 Advances for Networks \& Internet", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="This paper presents a new preemption-aware Quality of Service (QoS) routing algorithm for Instantaneous Request (IR) call connections in a QoS-enabled network where resources are shared between Instantenous Request (IR) and Book-Ahead (BA) call connections. Book-ahead reservation which confirms the availability of resources in advance is a highly attractive technique for time sensitive applications that require high amount of bandwidth with guaranteed QoS. One of the major concerns in the implementation of BA reservation is the preemption of on-going Instantaneous Requests (IR) call connections. Preemption disrupts service continuity which is seen as detrimental from users perceived QoS definition found in recent studies. Existing QoS routing algorithms focus on resource conservation or load balancing as the key objective to attain in addition to guaranteed QoS. No work known to these authors has yet focused on the preemption problem of on-going IR call connections at routing stage. We present a mathematical formulation to compute the preemption probability of an IR call connection at routing stage based on the current IR and future BA load information. We propose a routing strategy by formulating a link cost function comprising of calculated preemption probability of incoming IR call connection and hop count. Simulation results confirm that QoS routing based on the proposed link cost function significantly outperforms both shortest path and widest path routing algorithms in terms of preemption and call blocking rate." } @INPROCEEDINGS{Ahma0511:Vector, AUTHOR="Javad Ahmadi-Shokouh and Hengameh Keshavarz", TITLE="A {Vector-Hydrophones} Minimal Composition for Finite {Estimation-Variance} in {Direction-Finding} Near a Rigid Reflecting Boundary", BOOKTITLE="Globecom 2005 Signal Processing for Communications", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="An underwater acoustic vector-hydrophone is composed of two or three spatially collocated but orthogonally oriented velocity-hydrophones, plus an optional collocated pressure hydrophone. A minimum vector-hydrophone configuration is herein identified for finite-variance direction-finding by identifying the necessary and sufficient vector hydrophone composition configuration non-singularity in the Fisher Information Matrix. Recommended for direction finding near a rigid-boundary are a pressure hydrophone collocated with a collocated pair of x-axis and y-axis velocity hydrophones." } @INPROCEEDINGS{Ahme0405:High, AUTHOR="Bazil Ahmed and Miguel {Ramón.} and Leandro {Haro y Ariet.}", TITLE="High Altitude Platform {(HAP)} {W-CDMA} System Over Cities", BOOKTITLE="Vehicular Technology Conference Spring 2005 Satellite Networks and Services", ADDRESS="Stockholm, Sweden", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="The performance of downlink power control model, based on a n-th power distance law, is evaluated for high altitude platform station (HAPS) W-CDMA systems. The downlink capacity using this model is compared with the uplink capacity. It is shown that the uplink capacity is higher than the downlink capacity. As a case study it is shown that Madrid (the capital) can be covered by a platform with 169 beam. For a HAPS platform with 169 cells (beams) the total practical capacity of the system could be in the order of 10000 voice users or 1250 data users." } @INPROCEEDINGS{Ahme0504:High, AUTHOR="Bazil Ahmed", TITLE="High Altitude Platform {(HAP)} {W-CDMA} System Over Cities", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="The performance of downlink power control model, based on a n-th power distance law, is evaluated for high altitude platform station (HAPS) W-CDMA systems. The downlink capacity using this model is compared with the uplink capacity. It is shown that the uplink capacity is higher than the downlink capacity. As a case study it is shown that Madrid (the capital) can be covered by a platform with 169 beam. For a HAPS platform with 169 cells (beams) the total practical capacity of the system could be in the order of 10000 voice users or 1250 data users." } @INPROCEEDINGS{Ahme0504:Impact, AUTHOR="Bazil Ahmed", TITLE="Impact of Ultra Wide Band {(UWB)} on Digital Television Systems", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="The effect of the UWB transmitters on the digital television cell range is studied. The effect of the UWB transmitters on the DTV receiver (with a set-top antenna) performance is studied. It is shown that the DTV receiver can not tolerate an UWB power density of -70 dBm/MHz to -80 dBm/MHz when the separation between the UWB transmitter and the DTV receiver is 1 m. It can be noticed that the DTV receiver can tolerate an UWB power density of -100 dBm/MHz even if the separation is less than 1 m." } @INPROCEEDINGS{Ahme0505:New, AUTHOR="Usman Ahmed", TITLE="A New Processor Allocation and Pipelining Approach for Hardware Software Co-synthesis", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Hardware Software Co-synthesis problem is related to finding an optimal architecture for a given set of tasks related through data dependencies within certain constraints. The architecture consists of a set of heterogeneous processing elements executing various tasks and a communication structure between these processing elements. Many heuristic algorithms have been developed for hardware software co-synthesis but most of them are limited to simple architectures consisting of a single software processor with a hardware coprocessor. Many of the algorithms which consider multiple software components are also limited by simple shared bus architectures and non-pipelined implementations. A partitioning approach which targets pipelined implementation has been presented recently [1]. The method starts with a non-pipelined, hardware software partitioned task graph and iteratively divides the task graph into multiple pipeline stages. Since there is no interaction between task allocation and pipelining, the algorithm may result in implementations with redundant pipeline stages and extra memory. We present a new algorithm for processor allocation and pipelining. Our algorithm iteratively selects processing elements and tasks simultaneously for a pipeline stage. For each pipeline stage, a ready list of tasks is maintained. This list constitutes tasks with all their parents already allocated to a pipeline stage. The group of tasks and a corresponding set of processing elements is selected that minimizes the area and execution time of the target system. The current allocation is checked for timing constraints and this process is continued until no tasks from the ready list can be added into the current pipeline stage. At this point, the current pipeline stage is finalized and a new stage is initialized. The proposed algorithm performs processing-element and task allocation together and therefore produces better results. This algorithm is being employed as part of a complete hardware-software co-synthesis process." } @INPROCEEDINGS{Ahme0505:Overview, AUTHOR="Syed Ahmed", TITLE="Overview Of Oversampling Clock and Data Recovery Circuits", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Phase-Locked Loop (PLL) based Clock and Data Recovery (CDR) circuits use a 2x-oversampling (2XO) of the incoming Non-Return to Zero (NRZ) data stream to recover the data. As an extension of the idea, 3x-oversampling (3XO) CDR circuits provide improved performance in the presence of total asymmetric jitter. This paper presents an overview of the oversampling CDR circuits with an emphasis on digital architectures. These include, but are not limited to, the 3XO jitter-tolerant variable-interval 3XO architecture, the 3XO eye-tracking architecture, and the blind oversampling architecture. We propose a modified architecture that utilizes multiple rotating phases to improve the performance of the 3XO eye-tracking architecture." } @INPROCEEDINGS{Ahme0505:Topology, AUTHOR="Adnan Ahmed and Behrouz Homayoun Far", TITLE="Topology discovery for network fault management using mobile agents in ad hoc networks", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Managing todays complex and increasingly heterogeneous networks require in-depth knowledge and extensive training as well as collection of very large amount of data. As local area networks (LAN) increase in size and complexity, it becomes necessary to automate network management processes. Fault management is one of the functional areas of network management that entails detection, identification and correction of anomalies that disrupt services on a network. With the growing popularity of wireless ad hoc networks and the usage of mobile devices in networks this task has grown increasingly more difficult. An ad hoc network is a multi-hop network that consists of geographically distributed mobile and stationary nodes. The hosts communicate with one another without the support of a fixed infrastructure. The topology of such networks changes very often, making the task of network fault management almost impossible for traditional and centralized network management systems (NMS). In our previous work, a framework has been successfully implemented for distributed computation and detection of LAN faults by introducing Intelligent Agents (IA). The IA makes use of Bayesian networks as an intuitive modeling tool for bridging the gap between the information found in the Management Information Base (MIB) and the actual usage of such MIB variables in achieving fault identification. The system keeps a static view of the network, however, the NMS needs to have a current and up to date picture of the network in order to accurately manage faults. In the case of an infrastructureless network, such a picture would have to be made and updated automatically and in real-time. We propose a novel network discovery system using mobile agents to extend the capabilities and domain of our current fault management system to handle ad hoc networks. In this paper we show that our proposed system overcomes some of the drawbacks suffered by other similar systems. The advantages of using mobile agents as opposed to using static agents and centralized NMS for network discovery are also presented." } @INPROCEEDINGS{Ahme0506:Multidimensional, AUTHOR="Taher Ahmed and Maryvonne Miquel and Robert Laurin", TITLE="Supporting Decision Making for Spatiotemporal Phenomena", BOOKTITLE="3rd International Conference on Information Technology: Research and Education", ADDRESS="Hsinchu, Taiwan", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="Multidimensional structures are used in OLAP technology to aggregate and format data with the goal of optimizing responses to users queries. These structures have been widely used in applications that deal with discrete dimensions. In this paper we present a brief survey of the different multidimensional models and propose a model that supports both discrete and continuous dimensions with more concentration on the latter. We first define continuous fields. Then we present our model which is based on discrete and continuous basic cubes. By applying spatial and temporal interpolation functions to a sample of data of the discrete basic cube a continuous basic cube is constructed. Hypercubes are built by applying aggregation functions to basic cubes. Two classes of operations associated with continuous fields are also defined." } @INPROCEEDINGS{Ahme0509:Impact, AUTHOR="Bazil Ahmed", TITLE="Impact of Ultra Wide Band {(UWB)} on Digital Audio Broadcasting {(DAB)} and Digital Television {(DTV)} Systems", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="The effect of the UWB transmitters on the digital television cell range is studied. The effect of the UWB transmitters on the DAB receiver (with a set-top antenna) performance is studied. It is shown that the DAB receiver can not tolerate an UWB power density of -90 dBm/MHz when the separation between the UWB transmitter and the DAB receiver is 1 m at DAB frequency of 1465 MHz. It is noticed that the DAB receiver can tolerate an UWB power density of -105 dBm/MHz even if the separation is less than 1 m for DAB frequency of 200 MHz. It is shown that, the DTV receiver can not tolerate an UWB power density of -96 dBm/MHz when a separation between the UWB transmitter and the DTV receiver is 1 m at DTV frequency of 500 MHz ." } @INPROCEEDINGS{Ahme0511:Probabilistic, AUTHOR="Nadeem Ahmed and Salil Kanhere and Sanjay Jha", TITLE="Probabilistic Coverage in Wireless Sensor Networks", BOOKTITLE="Fifth International IEEE Workshop on Wireless Local Networks", DAYS=15, MONTH=nov, YEAR=2005, ABSTRACT="The sensing capabilities of networked sensors are affected by envoirnmental factors in real deployment and it is imperative to have practical considerations at the design stage in order to anticipate this sensing behaviour. We investigate the coverage issues in wireless sensor networks based on probabilistic coverage and propose a distributed Probabilistic Coverage Algorithm (PCA) to evaluate the degree of confidence in detection probability provided by a randomly deployed sensor network. The probabilistic approach is a deviation from the idealistic assumption of uniform circular disc for sensing coverage used in the binary detection model. Simulation results show that area coverage calculated by using PCA is more accurate than the idealistic binary detection model." } @INPROCEEDINGS{Ahme0511:Target, AUTHOR="Javed Ahmed and M. n. Jafri and J. Ahmad", TITLE="Target Tracking in an Image Sequence Using Wavelet Features and a Neural Network", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="In this paper, we present a comprehensive study to design an artificial neural network (ANN) for tracking a target in an image sequence. The proposed ANN architecture is a single-hidden-layer back-propagation neural network (BPNN), in which the sigmoid and the linear activation functions are used for its hidden and output layers, respectively. The features used for the input layer of the BPNN are 4th level Daubechiess wavelet decomposition coefficients corresponding to the input image. Performances of db1, db2, db3, and db4 wavelet features are compared. The object, which is tracked for the purpose of demonstration, is a specific airplane. However, the proposed ANN model can be trained to track any other object of interest. The trained ANN has been simulated and tested on the training and testing datasets. The tracking error is analyzed with post-regression analysis tool, which finds the correlation among the calculated coordinates and the correct coordinates of the object in the image. The promising results of the presented computer simulation and analysis show that the proposed target tracking technique exploiting the power of ANN and wavelet transform is quite plausible and significantly robust." } @INPROCEEDINGS{Ahn0504:Distributed, AUTHOR="Kye-Hyun Ahn", TITLE="Distributed Channel Access Control with Tunable {WADM} in {WDM} Ring Networks", BOOKTITLE="The 15th Joint Conference on Communication \& Information, 2005", ADDRESS="Hotel Inter Burgo, Daegu, Korea", DAYS=27, MONTH=apr, YEAR=2005, ABSTRACT="Access protocol for Metro networks is a key issue where there is still need to contribute with. And whether to use centralized or distributed access protocol is still a question to be answered. In this paper, we introduce the architecture of multi-wavelength optical ring networks suitable for deployment as MANs presented by Wonhon Cho and B. Mukherjee in Ref. [3] and propose a MAC protocol with distributed access control for the networks. Each node is equipped with a SONET ADM and a tunable Wavelength Add-Drop Multiplexer (WADM) instead of tunable or fixed transceivers. The cost and simplicity in a tunable WADM can be advantage to make an optical ring network. However, a tunable WADM has a property that the input wavelength must be the same with the output wavelength while transmitting or receiving some packets. It restricts efficient use of wavelength channels. In order to improve system performances, we adopt a distributed and slot basis access control. The propose MAC protocol provides efficient statistical multiplexing and fast packet access." } @INPROCEEDINGS{Ahn0504:Study, AUTHOR="JunBae Ahn and Kyoo-Tae Ryoo and Seong-Choon Lee", TITLE="The Study on the Implementation of the Digital Fiber Optical Repeater for Personal Internet", BOOKTITLE="The 15th Joint Conference on Communication \& Information, 2005", ADDRESS="Hotel Inter Burgo, Daegu, Korea", DAYS=27, MONTH=apr, YEAR=2005, ABSTRACT="In this paper, we has implemented and analyzed the digital fiber optical repeater for personal internet to provide services to a shadow area which do not reach RF signal. To implement the digital fiber optical repeater, speciallized technique are required like the method which distinguish TX from Rx in the TDD signal. We conclude that the repeater can expand cell coverage of RAS(Rasio Access Station) 1km to 3km without throughput degradation." } @INPROCEEDINGS{Ahn0509:Adaptive, AUTHOR="Chang-Jun Ahn", TITLE="Adaptive Subcarrier Block Modulation with Differentially Modulated Pilot Symbol Assistance for Downlink {OFDM} Using Uplink Delay Spread", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="In an AMS/OFDM system, base station is in control of the modulation level of each subcarrier, and then, adaptive modulated packet is transmitted from the base station to the mobile station. In this case, the mobile station is required the modulation level information (MLI) to demodulate the received packet. The MLI is generally transmitted as a data symbol, therefore, the throughput is degraded. In an OFDM, the channel response at a particular subcarrier frequency is not supposed to be totally different from its neighboring frequencies, and hence, they must have correlation which depends on the coherence bandwidth of the channel Bc. If we could assign the same modulation level for coherently faded subcarrier block, MLI is required only one time for each subcarrier block. Moreover, we can assign the data on the empty space of pilot signals for increasing the total transmission. In this paper, we propose an adaptive subcarrier block modulation with differentially modulated pilot symbol assistance for downlink OFDM using uplink delay spread." } @INPROCEEDINGS{Ahuj0510:Optimal, AUTHOR="Satyajeet Ahuja and Marwan Krunz and Turgay Korkmaz", TITLE="Optimal Path Selection for Ethernet Over {SONET} Under Inaccurate {Link-State} Information", BOOKTITLE="BROADNETS 2005 Optical Networking Symposium", DAYS=3, MONTH=oct, YEAR=2005, ABSTRACT={Ethernet over SONET (EoS) is a popular approach for interconnecting geographically distant Ethernet segments using a SONET transport infrastructure. It typically uses virtual concatenation (VC) for dynamic bandwidth management. The aggregate SONET bandwidth that supports a given EoS system is obtained by concatenating' a number of virtual channels (VCs), which together form a virtually concatenated group (VCG). This aggregate bandwidth can be increased on demand by adding one or more VCs to the existing VCG. The new VC (route) must be selected such that its end-to-end delay is within a certain range that reflects the delays of all existing VCs in the VCG and the available memory buffer of the EoS system. Algorithmically, the problem of selecting such a VC becomes that of finding a path in a graph network that is bounded by an upper and lower bounds (the lower bound being a positive number). This problem, known as the two-sided constrained path (TSCP) was first formulated in [2] assuming exactly known link delays, and a heuristic solution known as the MLW-KSP algorithm was proposed for solving it. In this paper, we first prove that the TSCP problem is NP-complete. We then propose a new solution for it based on the ``backward-forward{"} search approach. We show that this solution is much more efficient than the previously proposed MLW-KSP algorithm. We then consider the TSCP problem under inaccurate link information, in which the delay and available bandwidth for each link are taken as random variables. The problem is now formulated as that of finding the most probable path that satisfies the upper and lower delay constraints. We consider two cases. In the first case, we assume that the link delays are random but the link bandwidths are exact. We then consider the more general case where both the link delays and bandwidths are random. Heuristic solutions are presented for both cases. Simulations are conducted to evaluate the performance of the proposed algorithms and to demonstrate the advantages of the probabilistic path selection approach over the classic trigger-based approach.} } @INPROCEEDINGS{Aib0501:GSLA, AUTHOR="Issam Aib", TITLE="A {Multi-Party} Approach to {SLA} Modeling, Application to {WLANs}", BOOKTITLE="IEEE Consumer Communications and Networking Conference", ADDRESS="Las Vegas, Nevada", DAYS=3, MONTH=jan, YEAR=2005, ABSTRACT="In this paper, we propose a service-driven model for structuring WLANs into overlay networks of interacting Wireless Management Communities. A Wireless Management Community (WMC) is composed of a set of Parties and is governed by a charter named the WMC-SLA (Service Level Agreement). A WMC constitutes the basic unit of management upon which will be installed any form of service interaction between parties belonging to the wireless community. The WMC-SLA model is presented as a use case of a more general SLA model we name GSLA. The GSLA is an SLA information model that supports multi-party service relationships through a role-based mechanism. It is intended to catch up not only the complex nature of service interactivity intra and inter WMCs but also the broader range of SLA modeling of all sorts of IT business relationships. This model accommodates both granularity and modularity of behavioral specifications by having each party playing a role within a service relationship. It intends to bring a step towards SLA-driven management within pervasive service environments." } @INPROCEEDINGS{Aida0511:Cluster, AUTHOR="Masaki Aida and Keisuke Ishibashi and Chisa Takano and Hiroyoshi Miwa and Kaori Muranaka and Akira Miura", TITLE="Cluster Structures in Topology of {Large-Scale} Social Networks Revealed by Traffic Data", BOOKTITLE="Globecom 2005 General Conference", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="Many studies of social networks have recently been published. Interest in topological structures, such as scale-free characteristics, has been particularly strong. In this paper, we focus on the analysis of macro traffic data in a communications network of cellular phone users as a way of investigating large-scale social networks. Behaviors of information exchange between pairs of cellular phone users are reflected in traffic data, which thus reflects interesting features of social networks. We analyze the relationship between the number of customers and the volume of traffic with a view to finding clues about the structure of social networks among the very large set of potential customers. We then demonstrate some interesting features that our analysis reveals: a scale-free topology of human relations, their cluster structures, and behaviors of user-dynamics. In addition, we consider the relationship between traffic volume and the number of customers depending on the situation." } @INPROCEEDINGS{Aiss0505:Resource, AUTHOR="Ghassane Aniba and Sonia Aissa", TITLE="Resource Allocation in {HSDPA} Using {Best-Users} Selection Under Code Constraints", BOOKTITLE="Vehicular Technology Conference Spring 2005 Mobile Networks", ADDRESS="Stockholm, Sweden", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="We consider the open issue of scheduling in HSDPA networks for the purpose of enhancing the system's performance both in terms of throughput and fairness while taking into consideration resource constraints specific to the HSDPA architecture. In particular, we propose a two-best user scheduling approach with a selection criterion designed to ensure adaptive proportional fairness between users with different resource requirements and constraints. Compared to the popular Carrier-to-Interference Ratio (CIR) and Proportional Fairness (PF) methods, the proposed technique, called two-best Adaptive Proportional Fairness (APF) is shown to provide higher performance both in terms of throughput and fairness even when users experience different channel propagating conditions." } @INPROCEEDINGS{Aiza0505:Peak, AUTHOR="Naoki Aizawa and Osamu Muta and Yoshihiko Akaiwa", TITLE="Peak Power Cancellation of an {OFCDM} Signal Applied to an Adaptive Predistorted Power Amplifier", BOOKTITLE="Vehicular Technology Conference Spring 2005 Wireless Access", ADDRESS="Stockholm, Sweden", DAYS=28, MONTH=may, YEAR=2005, ABSTRACT="In recent years, in mobile communications, the demands for multimedia transmission are increasing. As a high speed transmission system, Orthogonal Frequency and Code Division Multiplexing (OFCDM) has been considered for the beyond 3G Systems. OFCDM system has a problem that the Peak to Average Power Ratio (PAPR) increases as the number of sub-carriers become higher. A high peak power causes the nonlinear distortion and out-of-band radiation or low power efficiency at the power amplifier. Therefore, it is important to reduce peak power of OFCDM signal. Thus we consider peak reducing signal addition (PRSA) method is suited for peak power reduction of OFCDM signal, which proposed for OFDM signal. Another approach to solve the problem of nonlinearity of a power amplifier is to use a predistorter. In this paper, we investigate the performance of OFCDM with PRSA applied to an adaptive predistortor power amplifier. We show that the peak reduction scheme PRSA and adaptive predistortion gives a high efficiency and high linearity in power amplification of OFCDM signal." } @TECHREPORT{Ajan0510:Connection, AUTHOR="Oskari Ajanki and Antti Knowles", TITLE="Connection state overhead in a dynamic linear network", TYPE="arXiv report", INSTITUTION="arXiv", NUMBER="cs.IT/0510077", MONTH=oct, YEAR=2005, ABSTRACT="We consider a dynamical linear network where nearest neighbours communicate via links whose states form binary (open/closed) valued independent and identically distributed Markov processes. Our main result is the tight information-theoretic lower bound on the network traffic required by the connection state overhead, or the information required for all nodes to know their connected neighbourhood. These results, and especially their possible generalisations to more realistic network models, could give us valuable understanding of the unavoidable protocol overheads in rapidly changing Ad hoc and sensor networks.", URL="http://arXiv.org/abs/cs/0510077" } @INPROCEEDINGS{Ajib0509:Efficient, AUTHOR="Wessam Ajib and Jean-François Frigon and David Haccoun", TITLE="Efficient Link Layer Transmission Strategy for {MIMO} Wireless Systems", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="This paper investigates link layer data units (frames) transmission strategies for MIMO wireless systems using spatial multiplexing. A new effective transmission strategy is proposed in this paper in order to decrease the frame error rate by making use of the multi-channel transmission characteristics provided in MIMO systems. The main idea is to select, in the context of a V-BLAST transmitter, between transmitting each frame, where a frame corresponds to an error correcting code word, from one antenna or from multiple antennas according to the channel state. Limited binary feedback information allows the transmitter to select the appropriate frame transmission policy. Analytical studies and simulations provided in this paper determine the optimal selection criterion and highlight the gains obtained by the proposed transmission strategy. This paper confirms that always transmitting each frame from multiple antennas gives quasi optimal performances." } @INPROCEEDINGS{Ajib0509:Efficient, AUTHOR="Wessam Ajib and David Haccoun and Jean-François Frigon", TITLE="An Efficient {QoS-based} Scheduling Algorithm for {MIMO} Wireless Systems", BOOKTITLE="VTC'F05 Wireless Access", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="In this paper, we propose a new QoS-based scheduling algorithm to be used in multiuser MIMO systems. Our proposal is a cross-layer technique where the MAC layer attempts to exploit the MIMO gains, which are traditionally exploited at the physical layer only. Our proposed scheduling algorithm improves the performance by considering the traffic profile (e.g., file size) and QoS requirements (e.g., delay constraint) as well as the channel state information." } @INPROCEEDINGS{Ajoo0504:Hardware, AUTHOR="Wafik Ajoor", TITLE="Hardware Design and Development of a Novel Adaptive Frequency Hopping Algorithm for the Coexistence of Bluetooth and {WLAN}", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="Bluetooth and WLAN (IEEE802.11b) are two promising short-range wireless technologies. Bluetooth offers wireless data services at 1 Mbps data rate within 10 meters distance. Bluetooth employs FHSS which divides the 2400-2483.5 MHz spectrum into 79 channels equally spaced by 1 MHz each. On the other hand, WLAN delivers services at various rates (1, 2, 5.5 and 11 Mbps) within a distance of 100 meters. Because of spreading, a WLAN data packet occupies a wide band of 23 MHz for the entire duration of packet transmission. When Bluetooth and WLAN overlap by at least one bit, Bluetooth packet will be corrupted by WLAN packet and vise versa. The probability of Bluetooth packet being interfered by a WLAN packet is 23/79 = 0.29. Therefore, 29\% of the Bluetooth packets are interfered by a collocated WLAN signal. Assuming that L and H represents the length of WLAN and Bluetooth packets, respectively, Ennis [2] has shown that the probability of a WLAN packet suffering interference due to a Bluetooth packet is: 1 (56/79)\L/H\ * (\L/H\ L/H) (56/79)(\L/H\ + 1) * (1 \L/H\ + L/H). Assuming that L = 727 µs and H = 366 µs. The above expression produces a value of 0.65. Thus, 65\% of the WLAN packets are interfered by Bluetooth hopping. Therefore, it is important to take all precautions to reduce mutual interference between Bluetooth and WLAN. Approaches have been proposed in the literature to reduce mutual interference [3-6]. We presented a novel Adaptive Frequency Hopping (AFH) algorithm to mitigate this mutual interference in [1]. One of our scheme advantages is its easy implementation in hardware. In this paper we present a hardware implementation of the AFH algorithm. There are a number of motivations for implementing the AFH scheme in hardware. (1) High performance: since the AFH is an adds-on box to Bluetooth Hop Selection Box, hardware implementation is a good choice for the AFH scheme in order to achieve the required performance. (2) Flexibility: hardware programmability, which enables future upgrades. The hardware simulation of the AFH System showed a successful and accurate modeling. Altera tools reported the utilization, in terms of logic cells, of APEX FPGA device to be 14\%. Therefore, employing the AFH System, a 29\% loss in the Bluetooth throughput and a 65\% loss in the WLAN throughput were recovered. REFERENCES 1. W. Ajoor, S. Naik, and S. Safavi-Naeini, An Adaptive Frequency Hopping Algorithm for the Coexistence of Bluetooth and WLAN, 5th World Wireless Congress, pp. 125-129, San Francisco-USA, May 25-28, 2004. 2. G. Ennis, Impact of Bluetooth on 802.11 Direct Sequence, IEEE802.11-98/319, September 1998. 3. S. Shellhammer and J. Lansford, Collaborative Coexistence Mechanism Submission: Mobilian's META + Symbol's TDMA, IEEE802.15-01/164r0, Symbol Technologies/Mobilian Corporation, March 2001. 4. N. Golmie and N. Chevrollier, Power Control and Packet Scheduling for Bluetooth to Avoid 802.11 Direct Sequence Interference, IEEE 802.15-01/063r0, January 2001. 5. M. B. Shoemake, Proposal for Non-collaborative 802.11 MAC Mechanisms for Enhancing Coexistence: Adaptive Fragmentation, IEEE 802.15-01/083r0, Texas Instruments Inc., January 2001. 6. H. Gan and B. Treister et al., Adaptive Frequency Hopping: A Non-collaborative Coexistence Mechanism, IEEE802.15-00/367r1, Bandspeed Inc., March 2001. 7. The Bluetooth Special Interest Group. Bluetooth Specification version 1.1b. http://www.bluetooth.com,2001. 8. K. C. Chang, Digital Systems Design with VHDL and Synthesis: An Integrated Approach, IEEE Press, 1999. 9. B. Cohen, VHDL Coding Styles \& Methodologies, Khuwer Academic, 1995." } @INPROCEEDINGS{Akag0501:IP, AUTHOR="Hiroshi Akagi and Makoto Adachi", TITLE="{IP-based} {AV} Home Network System", BOOKTITLE="IEEE Consumer Communications and Networking Conference Poster Session", ADDRESS="Las Vegas, Nevada", DAYS=3, MONTH=jan, YEAR=2005, ABSTRACT="We have developed a prototype of the real time AV transmission system for high quality MPEG2-TS stream over IP-based home network. By using the prototype, we have proved the effectiveness of basic framework of DTCP-IP and our newly developed small delay and precise de-jittering technology for high quality streaming. This system can achieve the high quality AV transmission over the various high speed home network media such as WLAN, Ethernet, PLC, Coax and UWB." } @INPROCEEDINGS{Akar0502:Differentiated, AUTHOR="Nail Akar and Hakan Boyraz", TITLE="Differentiated {ABR:} A New Architecture for Flow Control and Service Differentiation in Optical Burst Switched Networks", BOOKTITLE="9th Optical Network Design and Modelling 2005", ADDRESS="Milano, Italy", DAYS=7, MONTH=feb, YEAR=2005, ABSTRACT="In this paper, we study a new control plane protocol, called Differentiated ABR (D-ABR), for flow control and service differentiation in optical burst switching networks. Using D-ABR, we show using simulations that the optical network can be designed to work at any desired burst blocking probability by the flow control service of the proposed architecture. The proposed architecture requires certain modifications to the existing control plane mechanisms as well as incorporation of advanced scheduling mechanisms at the ingress nodes; however we do not make any specific assumptions on the data plane of the optical nodes. Moreover, with this protocol, it is possible to almost perfectly isolate high priority and low priority traffic throughout the optical network as in the strict priority-based service differentiation in electronically switched networks." } @INPROCEEDINGS{Akay0505:Low, AUTHOR="Enis Akay and Ender Ayanoglu", TITLE="Low Complexity Decoding of {BICM} {STBC}", BOOKTITLE="Vehicular Technology Conference Spring 2005 Transmission Technology", ADDRESS="Stockholm, Sweden", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="It was shown earlier that the combination of bit interleaved coded modulation (BICM) with space time block codes (STBC) for OFDM systems leads to the maximum diversity order in space and frequency. In this paper we present low complexity decoding of BICM-STBC systems. First, the maximum likelihood (ML) bit metric calculations are simplified from a distance on the complex plane to a distance on the real line. Furthermore, we present log-likelihood-ratio (LLR) approximations to maximum likelihood (ML) decoding metrics to achieve easier to implement soft decision bit metrics with the same high performance. The LLR bit metrics are specifically calculated for $M$-ary QAM signal constellations used in IEEE 802.11a/g networks. Simulation results also show that while achieving a substantial improvement in decoder complexity, the proposed bit metrics achieve the same high performance." } @INPROCEEDINGS{Akay0505:Performance, AUTHOR="Enis Akay and Ersin Sengul and Ender Ayanoglu", TITLE="Performance Analysis of Beamforming for {MIMO} {OFDM} with {BICM}", BOOKTITLE="ICC 2005 Communication Theory", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="In this paper we will show and quantify both analytically and via simulations that the use of channel knowledge at the transmitter, the technique known as beamforming, achieves the maximum diversity in space when the best eigenmode is used (single beamforming). Furthermore, we will investigate beamforming in conjunction with next generation wireless local area networks (WLANs). It is known that the widely used technique in WLANs, bit interleaved coded modulation (BICM) with orthogonal frequency division multiplexing (OFDM), can achieve the maximum frequency diversity order that is inherited in the channel. We will show that the combination of BICM, single beamforming, and OFDM also leads to the maximum diversity order in space and frequency domains. In other words, for systems with N transmit and M receive antennas, BICM - Beamforming - OFDM (BBO) can achieve a diversity order of NML over L-tap frequency selective channels by using an appropriate convolutional code. In addition to having a substantial diversity order, simulation results showed that beamforming and BBO introduce significant coding gains when compared to other systems based on space time block codes (STBC) with the same diversity order." } @INPROCEEDINGS{Akel0505:Analysis, AUTHOR="Jayasri Akella and Murat Yuksel and Shivkumar Kalyanaraman", TITLE="Error Analysis of {Multi-Hop} Free Space Optical Communication", BOOKTITLE="ICC 2005 Optical Networking", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="In this paper we analyze error performance of Free Space Optical (FSO) communication over multiple hops. We first develop an error model for a single hop based on visibility, atmospheric attenuation and geometric spread of light beam. As atmospheric visibility is natural phenomenon, we model it by Gaussian distribution with different mean and variance values to reflect clear and adverse weather conditions. Based on this we find the end to end bit error distribution of the FSO link for single hop and multihop scenarios. We present simulation results for decoded relaying, where each hop decodes teh signal before retransmitting. We demonstrate that multihop FSO communication achieves a significant reduction in the mean bit error rate and also reduction in the variance of the bit error rate. We argue that due to lower mean error and lower error variance, multihop operation facilitates an efficient system design to improve the reliability of the FSO link by application of specific coding schemes (e.g. FEC)." } @INPROCEEDINGS{Akel0508:Self, AUTHOR="Aditya Akella and Glenn Judd and Srinivasan Seshan and Peter Steenkiste", TITLE="{Self-Management} in Chaotic Wireless Deployments", BOOKTITLE="11th Annual International Conference on Mobile Computing and Networking", ADDRESS="Cologne, Germany", DAYS=28, MONTH=aug, YEAR=2005, ABSTRACT="Over the past few years, wireless networing technologies have made vast forays into our daily lives. Today, one can find 802.11 hardware and other personal wireless technology employed at homes, shopping malls, coffee shops and airports. Present-day wireless network deployments bear two important properties: they are unplanned, with most Access Points (APs) deployed by users in a spontaneous manner, resulting in highly variable AP densities; and they are unmanaged, since manually configuring and managing a wireless network is very complicated. We refer to such wireless deployments as being {\em chaotic}. In this paper, we present a study of the impact of interference in chaotic 802.11 deployments on end-client performance. First, using large-scale measurement data from several cities, we show that tens of APs are deployed in close proximity of each other. Moreover, most APs are not configured to minimize interference with their neighbors. We then perform trace-driven simulations to show that the performance of end-clients could suffer significantly in chaotic wireless deployments. Furthermore, we argue that end-client experience could be significantly improved by making chaotic wireless networks {\em self-managing}. We design and evaluate automated power control and rate adaptation algorithms (for both APs and clients) to minimize interference among neighboring APs, while ensuring robust end-client performance." } @INPROCEEDINGS{Akha0505:Performance, AUTHOR="Mahshid Akhavan-Bahabadi and S. Hamidreza Jamali", TITLE="Product Codes for Multicarrier {DS-CDMA} Systems", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="In this paper, we apply a class of multidimensional single parity check (SPC) product codes, to a multicarrier asynchronous direct sequence code division multiple access (DS-CDMA) system in such away that the transmission rate of information and the transmitted signal bandwidth of the uncoded system are not changed. In the proposed system the output of an SPC turbo product encoder is repetition coded and modulates multiple band-limited DS-CDMA waveforms, which are transmitted in parallel at different carrier frequencies. The receiver detects and maximal ratio combines signals for the desired user and feeds an iterative log-Map decoder. The performance of the coded multicarrier system is compared to that of a conventional single-carrier DS-CDMA system employing a RAKE receiver, assuming a slowly varying frequency-selective Rayleigh fading channel. Where the number of tones is taken to be equal to the number of resolvable paths in the single carrier system. At greater transmitter complexity, but roughly equivalent receiver complexity, results will demonstrate similar performance in presence of additive white Gaussian noise (AWGN) and multiple access interference (MAI) and superior performance of the multicarrier system in the presence of partial band interference (PBI), which is due to the ability of the multicarrier system to effectively suppress the interference using the innate structure of its receiver, without the added complexity of a front-end interference suppression or notch filter." } @INPROCEEDINGS{Akhb0508:High, AUTHOR="Mohammad Akhbarizadeh and Mehrdad Nourani and Rina Panigrahy and Samar Sharma", TITLE="{High-Speed} and {Low-Power} Network Search Engine Using Adaptive {Block-Selection} Scheme", BOOKTITLE="Hot Interconnects 13", ADDRESS="Stanford, CA", DAYS=17, MONTH=aug, YEAR=2005, ABSTRACT="We propose a new approach for using the block-selection scheme to increase the search throughput in a multi-block TCAM-based network search engine. While the existing methods try to counter and forcibly balance the inherent bias of the Internet traffic, our method takes advantage of it. The result is improving flexibility of table management and gaining scalability towards high rates of change in traffic bias. This approach offers higher throughput than the current art and a very low average power consumption. One of the embodiments of the proposed model, using four TCAM chips, can deliver more than six times the throughput of a conventional configuration of the same TCAM chips." } @INPROCEEDINGS{Akhb0511:Watermarking, AUTHOR="Bahareh Akhbari", TITLE="Watermarking of Still Images in Wavelet Domain based on Entropy Masking Model", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="A new robust image adaptive digital watermarking algorithm in wavelet transform domain is proposed in this paper. The proposed method exploits Human Visual System (HVS) characteristics and entropy masking concept to determine image adaptive thresholds for selection of perceptually significant coefficients. The mark is embedded in the coefficients of all subbands including the LL subband. Experimental results show that the proposed method significantly improves watermarking performance over conventional methods, in the terms of invisibility and robustness." } @INPROCEEDINGS{Akho0504:Long, AUTHOR="Mehdi Akhondi", TITLE="{Long-Term} Cumulative Distribution Modeling of Tropospheric Scintillation for the {Earth-Satellite} Links in the V-band", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="Abstract: In this paper, we have obtained a model for the prediction of scintillation fade depth, scintillation intensity, and cumulative distribution of its intensity, in the 40/50 GHz band. By applying a regression analysis to the experimental data collected at Madrid, a new model is proposed. Moreover, the prediction accuracy of the our new model is evaluated using the experimental results from Spino dAdda, Italy." } @INPROCEEDINGS{Akho0504:Long, AUTHOR="Mehdi Akhondi and Ayaz Ghorbani", TITLE="{Long-Term} Cumulative Distribution Modeling of Tropospheric Scintillation for the {Earth-Satellite} Links in the {40/50} {GHz} band", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="In this paper, we are going to obtain a model for the prediction of scintillation fade depth, scintillation intensity, and cumulative distribution of its intensity, in the 40/50 GHz band. By applying a regression analysis to the experimental data collected at Madrid, a new model is proposed. Moreover, the prediction accuracy of the our new model is evaluated based on the experimental results from Spino dAdda, Italy." } @INPROCEEDINGS{Akim0503:High, AUTHOR="Yosuke Akimoto and Yushi Shirato and Kazuji Watanabe", TITLE="A {High-Precision} {AFC} Circuit Applied to {64QAM} {Point-to-Multipoint} Burst Communications", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="In this paper, we propose a novel Automatic Frequency Control (AFC) circuit suitable for 64QAM point-to-multipoint (P-MP) burst communications. The proposed AFC circuit calculates the phase rotation during a sufficiently long time and adopts the Variable-gain Least Mean Squares (VLMS) algorithm to estimate the carrier frequency offset. The proposed AFC circuit is implemented with approximately 50?kgates. Its complexity level is much lower than that of the conventional one. The computer simulation and experimental results confirm achieving the frequency error of 5.3x10-6, and that it is sufficient for developing 64QAM ? 40 Mbaud system." } @INPROCEEDINGS{Akin0511:Proposal, AUTHOR="Yoshikazu Akinaga and Shigeru Kaneda and Noriteru Shinagawa and Akira Miura", TITLE="A proposal for a mobile communication traffic forecasting method using time-series analysis for multi-variate data", BOOKTITLE="Globecom 2005 Autonomic Internet", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="In the present mobile network, the management of the radio resource to connect users and edge networks is an important issue. If there is a rapid rise in traffic coming into the network, regulation methods such as admission control or admission avoidance are the only way of dealing with this. Since it is beyond the mobile network systemfs capability to predict fluctuations in traffic for every area, there are great difficulties in realizing other control methods. In order to solve these problems, this paper proposes a method of forecasting traffic systematically based on the userfs properties and information about the environment." } @INPROCEEDINGS{Akko0511:Multiple, AUTHOR="Gun Akkor and John S. Baras and Michael Hadjitheodosiou", TITLE="A multiple subset sum formulation for feedback implosion suppression over satellite networks", BOOKTITLE="Globecom 2005 Wireless Communications", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="In this paper, we present a feedback implosion suppression (FIS) algorithm that reduces the volume of feedback information transmitted through the network without relying on any collaboration between users, or on any infrastructure other than the satellite network. Next generation satellite systems that utilize the Ka frequency band are likely to rely on various fade mitigation techniques, in order to guarantee a service quality that is comparable to other broadband technologies. User feedback would be a valuable input for a number of such components, however, collecting periodic feedback from a large number of users would result in the well-known feedback implosion problem. Feedback implosion is identified as a major problem when a large number of users try to transmit their feedback messages through the network, holding up a significant portion of the uplink resources and clogging the shared uplink medium. In this paper, we look at a system where uplink channel access is organized in time-slots. The goal of the FIS algorithm is to reduce the number of uplink time-slots hold up for the purpose of feedback transmission. Our analysis show that the FIS algorithm effectively suppresses the feedback messages of 95\% of all active users, but still achieves acceptable performance results when the ratio of available time-slots to number of users is equal to or higher than 5\%." } @INPROCEEDINGS{Akl0503:Throughput, AUTHOR="Robert Akl and Mort Naraghi-Pour and Manjunath Hegde", TITLE="Throughput Optimization in {Multi-Cell} {CDMA} Networks", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="In this paper, we investigate the performance of a multi-cell CDMA network by determining the maximum throughput that the network can achieve for a given grade-of-service requirement, quality-of-service requirement, network topology and call arrival rate profile. Our analysis is restricted to the reverse link and accounts for mobility of users between cells. A constrained nonlinear optimization problem is formulated that maximizes the network throughput subject to upper bounds on the blocking probabilities and a lower bound on the bit energy to interference ratio. The goal is to optimize the usage of network resources, provide consistent grade-of-service for all the cells in the network, and maintain a pre-specified quality-of-service. The solution to the optimization problem yields the maximum network throughput as well as the maximum number of calls that should be admitted in each cell for a given topology and call arrival rate profile. Our optimization algorithm yields significantly higher throughput compared with traditional call admission schemes." } @INPROCEEDINGS{Akon0512:Extensible, AUTHOR="Mohammad Akon and Ajit Singh and Dhrubajyoti Goswami and Hon Li", TITLE="Extensible Parallel Architectural Skeletons", BOOKTITLE="12th Annual IEEE International Conference on High Performance Computing", ADDRESS="Goa, India", DAYS=18, MONTH=dec, YEAR=2005, ABSTRACT="Complexity of parallel application development has been one of the major obstacles towards the mainstream adoption of parallel programming. In order to hide some of these complexities, researchers have been actively investigating the pattern-based approaches to parallel programming. As reusable components, patterns are intended to ease the design and development phases of parallel applications. Parallel Architectural Skeleton (PAS) is one such pattern-based parallel programming model which describes the architectural aspects of parallel patterns. Like many other pattern-based parallel programming models and tools, the benefits of PAS were offset by the difficulties in extending PAS, whereby new skeletons can be systematically added to the existing skeleton repository. SuperPAS is an extension of PAS that addresses this issue. Using SuperPAS, a skeleton designer can design new skeletons and add them to the skeleton repository (i.e., extensibility). SuperPAS also makes the PAS model more flexible by defining composition of skeletons. In this paper, we describe the model of SuperPAS and also discuss some of the recent usability and performance studies. The studies demonstrate that SuperPAS is a practical and usable parallel programming model and tool." } @INPROCEEDINGS{Akri0505:Efficient, AUTHOR="Periklis Akritidis and Evangelos Markatos", TITLE="Efficient {Content-Based} Fingerprinting of {Zero-Day} Worms", BOOKTITLE="ICC 2005 General Conference", ADDRESS="Seoul, Korean", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="Recent cybersecurity incidents suggest that Internet worms can spread so fast that in-time human-mediated reaction is not possible, and therefore initial response to cyberattacks has to be automated. The first step towards combating new unknown worms is to be able to detect and identify them at the first stages of their spread. In this paper, we present a novel method for detecting new worms based on identifying similar packet contents directed to multiple destination hosts. We evaluate our method using real traffic traces that contain real worms. Our results suggest that our approach is able to identify novel worms while at the same time the generated false alarms reach as low as zero percent." } @INPROCEEDINGS{Al-B0511:Block, AUTHOR="Abdul Karim Al-Bayati and Shankar Prakriya and Surendra Prasad", TITLE="Block Phase Precoding for Blind Multi-user Detection in {QPSK/DS-CDMA} Systems", BOOKTITLE="Globecom 2005 Communication Theory", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="We address the problem of blind multiuser detection in DS/CDMA systems that employ QPSK data modulation. We show that that by suitable precoding (modification) of the phase of the QPSK data at the transmitter (before spectrum spreading), it is possible to detect the data of any user blindly using only the knowledge of the precoding sequence, regardless of the power of the interferers. The proposed method can be seen as an extension to our earlier precoding approach for BPSK signals in [9]. However, the phase precoding/decoding operation of QPSK signals is a more challenging problem, especially in its decoding procedure. The proposed detection scheme has a deterministic nature and is therefore shown to provide performance advantage in the medium-to- high SNR region." } @INPROCEEDINGS{Al-B0511:Review, AUTHOR="Mohammad Al-Batah and Nor Ashidi {Mat Isa} and Mohammad Mashor and Khairun Azizli and Ariffuddin Joret", TITLE="A Review on {3D} Object Representation and Recognition", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="The recognition of objects is one of the most challenging goals in computer vision. The problems increase when the process of recognition involved three dimensional (3D) objects. To deal with this problem, many researchers have proposed their own solution. This paper gives a short review of some of the researches in the area in representing their 3D models. It is intended to be a summary of the important research issue and approaches that researchers have taken and how these techniques are related." } @INPROCEEDINGS{Al-D0503:Intentional, AUTHOR="Basheer Al-Duwairi and Manimaran Govindarasu", TITLE="Intentional Dropping: A Novel Scheme for {SYN} Flooding Mitigation", BOOKTITLE="Global Internet 2005", ADDRESS="Miami, FL, USA", DAYS=17, MONTH=mar, YEAR=2005, ABSTRACT="This paper presents a novel scheme to mitigate the effect of SYN flooding attacks. The scheme, called intentional dropping based filtering, is based on the observation of client's persistence (i.e., client's reaction to packet loss by subsequent retransmissions) which is very widespread as it is built in TCP's connection setup. The main idea is to intentionally drop the first SYN packet of each connection request. Subsequent SYN packet from a request is passed only if it adheres to the TCP's timeout mechanism. Our analysis shows that the proposed scheme reduces attacker's effective attack rate significantly with an acceptable increase in connection establishment latency." } @INPROCEEDINGS{Al-D0503:New, AUTHOR="Naofal Al-Dhahir and Hlaing Minn", TITLE="A New Multicarrier Transceiver Based on the Discrete Cosine Transform", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="We derive conditions on the impulse response and input signal of a frequency-selective FIR channel to be diagonalized by the DCT into parallel, decoupled, and memoryless subchannels. We show how these conditions can be satisfied in a practical multi-carrier transceiver through a novel design of the guard sequence and the front-end prefilter. This DCT-based design completely eliminates inter-block and inter-carrier interference at a lower complexity and without incurring any additional guard sequence overhead compared to DFT-based multicarrier transceivers. Extensions to multi-input multi-output frequency-selective channels are also described." } @INPROCEEDINGS{Al-D0505:Victim, AUTHOR="Basheer Al-Duwairi and Manimaran Govindarasu", TITLE="{Victim-Assisted} Mitigation Technique for {TCP} Based Reflector {DDoS} Attacks", BOOKTITLE="NETWORKING 2005", ADDRESS="Waterloo, Ontario, Canada", DAYS=2, MONTH=may, YEAR=2005, ABSTRACT="This paper advocates the concept of victim-assistance for denial of service mitigation. The proposed concept is utilized within a simple, yet effective scheme designed for mitigating TCP-based reflector DoS attacks. The proposed scheme, called SYN number based filtering (SNF), takes into account the working of the TCP protocol as well as the inherent features of the attack itself. The main idea of the SNF scheme is to restrict the choice of the initial sequence numbers of SYN packets to certain pattern, such that corresponding SYN-ACK packets can be validated at the ISP's perimeter. We evaluate the proposed scheme through analytical studies for classical and advanced attacks using two performance metrics, namely, the false positives and false negatives rates. Our analysis shows that the proposed scheme offers low false positives and false negatives rates." } @INPROCEEDINGS{Al-G0504:Uplink, AUTHOR="Salman Al-Gahtani and Ashraf Mahmoud", TITLE="Uplink Admission Control in {WCDMA}", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="Abstract: The 3G cellular mobile systems based on WCDMA technology are expected to be interference limited. Soft capacity is one of the main characteristics of 3G ( i.e, UMTS) and it requires new radio resource management strategies to serve diverse quality of service requirements. In this paper we formulate the soft uplink capacity of a 3G WCDMA cell as a function of bandwidth and interference and the capacity utilization of an individual user as a function of the users traffic class and activity factor. A WCDMA prioritized uplink admission control algorithm for UMTS, which combines QoS negotiation and service differentiation by priority, is studied. The dropping of a soft handoff call (which is an ongoing call) is considered more disturbing than the blocking of a new call. Therefore, prioritizing soft handoff calls is an important way to reduce handoff failures. This CAC scheme gives preferential treatment to high priority calls, such as soft handoff calls, by pre-reserving a certain amount of bandwidth margin (soft guard channel) against the interference effect to reduce handoff failures. In addition, queuing is also used to enhance the handoff success probability. It uses the effective load as an admission criterion and applies different thresholds for new calls and handoff calls respectively. Two type of services are considered, voice and data calls. Both voice and data services are accommodated without discriminating between soft handoff and new call requests if radio resources are available. However, soft handoff call requests (voice or data) are given priority over new calls (voice and data) by varying the effective load factor levels and by allowing the soft handoff calls to be queued when resources are insufficient to accept a soft handoff request. The simulation results of this scheme somewhat works well in terms of reducing the drop and increasing the GoS and hence the system performance can be significantly improved." } @INPROCEEDINGS{Al-G0509:Outage, AUTHOR="Samir Al-Ghadhban and Michael Buehrer and Brian Woerner", TITLE="Outage Capacity Comparison of {Multi-Layered} {STBC} and {V-BLAST} Systems", BOOKTITLE="VTC'F05 Transmission Technology", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="In this paper, we examine the capacity of high data rate open loop MIMO architectures. The focus of the study is to compare the information capacity of multi-layered space time block coded (MLSTBC) systems with V-BLAST and STBC. MLSTBC combines transmit diversity and spatial multiplexing. The single user data are divided into layers of information and each layer is encoded with a STBC. The result of this study shows that for the same number of transmit-receive antennas, MLSTBC is more power efficient than V-BLAST, since it provides more diversity. Furthermore, at low SNR and low outage probabilities, MLSTBC is more spectrally efficient. Thus, it is more suitable for low power high data rate wireless applications." } @INPROCEEDINGS{Al-H0504:Comparison, AUTHOR="Mohammed Al-Hunaity", TITLE="Comparison Analysis Between Topological Models Of Base Stations In Cellular Mobile Radio Communication", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="In this paper, we analyze the different parameters of quality for the network models of base stations (BS) when the service messages have not a delay. Also, we compare between four topologies star, ring, radial ring and fully connected using identical quality of user service and conditional cost of one Erlang. Our results have been obtained for different probabilities of failure in service message on one branch and fixed number of web channels. The obtained results show that radial ring topology outperform better than the others with respect to both cost and hierarchy." } @INPROCEEDINGS{Al-H0504:Efficient, AUTHOR="Saleh Alharthi", TITLE="An Efficient {CDMA} Scheme for Personal Area Networks", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="In this paper, we describe a scheme that allows N mobile nodes to communicate with one another simultaneously under the following constraint: No node may transmit and receive at the same time. Furthermore, we focus on a Personal Area Network (PAN) application limiting the network to a single-hop ad-hoc network. For the purposes of comparing our scheme to other proposals, we introduce a specific Bluetooth-based Code Division Multiple Access (CDMA) instance of the scheme that requires minimal changes to the current specification of Bluetooth. The importance of Bluetooth is evidenced by the fact that Bluetooth is becoming the de-facto standard for PANs and the fact that it is today becoming a standard feature on most consumer electronics products. Since the main target of Bluetooth is battery-operated mobile devices, improving the performance of Bluetooth, especially the power consumption of devices using Bluetooth, will be quite beneficial and desirable. The basic Bluetooth architecture is a master-slave architecture in which a group of at most seven nodes, called slaves, are controlled by a node, called a master. Each group of slaves and their master form a network called a piconet. In a generalized PAN piconet, the typical mode of communication between the nodes of the piconet is the ad-hoc mode. In a Bluetooth piconet, the master has absolute control of channel access. In such architecture, the master coordinates communication between nodes at the expense of exchanging extra control packets with the other nodes. We define theses extra control packets as overhead packets. An efficient piconet uses as minimum as possible of the coordinating overhead packets. The proposed Bluetooth-based CDMA scheme is shown to outperform the current Bluetooth specification in efficiency and in power consumption of all nodes of a piconet. Specifically, the Bluetooth-based CDMA piconet of the scheme is shown to achieve an overhead ratio as low as about 1\% (with seven active slaves in the piconet) compared to an overhead ratio of about 43\% for an equivalent (in number of nodes and traffic pattern) Bluetooth piconet. Furthermore, and contrary to the Bluetooth piconet, the overhead ratio of the proposed CDMA piconet decreases as the number of active slaves in the piconet increases. This means that the piconet of the proposed scheme becomes more efficient (compared with an equivalent Bluetooth piconet) as the number of active slaves increases in the piconet. It is also shown that the power consumed by a Bluetooth piconet is order of magnitudes higher than the power consumed by an equivalent piconet of the proposed scheme. As a specific example, a Bluetooth piconet with seven active slaves is shown to consume about 3.5 times (and up to about 10 times) the power consumed by an equivalent piconet of the proposed scheme." } @INPROCEEDINGS{Al-H0509:Multiuser, AUTHOR="Yahya Al-Harthi and Ahmed Tewfik and Mohamed-Slim Alouini", TITLE="Multiuser {Diversity-Enhanced} Equal Access with Quantized Feedback in Multicarrier {OFDM} Systems", BOOKTITLE="VTC'F05 Transmission Technology", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="Orthogonal frequency division multiplexing (OFDM) is emerging as a key modulation scheme for future high speed packets based wireless transmission systems. In a wireless multiuser network system, when an opportunistic scheduling is employed in the OFDM system with adaptive modulation, it may encounter implementation problems due to the need for a large amount of channel information. In this paper, we propose an optimal discrete rate switch-based multi-user diversity system (DSMUDiv) that reduces the feedback load while maintaining the performance of opportunistic scheduling. We present an analytical analysis of the feedback load and spectral efficiency of the proposed scheme. To guarantee a high probability of access for each user we are adopting the idea of Enhanced Equal Access scheduling policy suggested earlier and we present computer simulation to evaluate the performance of the scheme." } @INPROCEEDINGS{Al-H0509:Transferring, AUTHOR="Yahya Al-Harthi and Ahmed Tewfik and Mohamed-Slim Alouini", TITLE="Transferring Multimedia Files using Adaptive Transmission in Infostation Technology", BOOKTITLE="VTC'F05 Wireless Personal Communication Systems", DAYS=25, MONTH=sep, YEAR=2005, ABSTRACT="In this paper we propose to investigate the performance of a selective repeat automatic-repeat-request (SR-ARQ) scheme combined with adaptive modulation and Maximum Ratio Combining (MRC) to transfer fragmented large multimedia files over Infostations networks. Based on the channel state information (CSI), the modulation level can be switched dynamically. Adaptive fragment size is also considered depending on the CSI. We will consider two access options: (i) sit-through access, and (ii) drive-through access. Closed-form expressions and computer simulations will be provided to evaluate the performance of the system." } @INPROCEEDINGS{Al-H0511:Interoperating, AUTHOR="Yousef Al-Houmaily", TITLE="On Interoperating Incompatible Atomic Commit Protocols in Distributed Databases", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="This paper proposes an adaptive participant's presumption protocol (AP3) that can be used to atomically commit Internet transactions. AP3 interoperates a one-phase commit protocol, namely, implicit-yes vote, and two-phase commit protocols, namely, presumed abort and presumed commit, in a dynamic fashion. Thus, it offers the performance advantage of the combined protocols, whenever possible, while still providing the wide applicability of two-phase commit protocols. This is achieved in spite of the incompatibilities between atomic commit protocols that lead to the general practice of adopting a single atomic commit protocol in any distributed database system." } @INPROCEEDINGS{Al-H0511:Multiuser, AUTHOR="Yahya Al-Harthi and Ahmed Tewfik and Mohamed-Slim Alouini", TITLE="Multiuser Diversity with Quantized Feedback", BOOKTITLE="Globecom 2005 Wireless Communications", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="In this paper, we propose an optimal discrete rate switch-based multi-user diversity system (DSMUDiv) that reduces the feedback load while preserving the essential of the sch\-eme performance in some cases. We examine DSMUDiv scheme using two scheduling criteria depending on the distribution of the mobile users in the cell: (\textbf{i}) absolute signal-to-noise ratio (SNR)-based scheduling in the case of independent and identical distributed {\em (i.i.d.)} users, and (\textbf{ii}) normalized SNR-based scheduling in the case of {\em non-i.i.d.} usres. The paper includes the derivation of closed-form expressions of the feedback load in the case of absolute and normalized SNR-based scheduling and the spectral efficiency in the case of absolute SNR-based scheduling. Computer simulation is used to evaluate the spectral efficiency in the case of normalized SNR-based scheduling. Under slow Rayleigh fading assumption, we compare our scheme with the optimal (full feedback load) selective diversity scheme." } @INPROCEEDINGS{Al-H0511:Reverberation, AUTHOR="Azremi {Abdullah Al-Hadi}", TITLE="Reverberation Chamber for Efficiency Measurement of Small Antennas", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="Small antennas such as those used for cell phones cannot be measured accurately in conventional antenna measurement ranges. This is because in operation these antennas are immersed in a strong multipath environment with rays coming at them from many different directions. The antenna efficiency is the most important performance parameter of an antenna on a mobile terminal in a multipath environment. A reverberation chamber is a method of simulating the multipath environment in the laboratory. It consists of a metallic box containing the antenna under test, a transmitting antenna and various moving metallic paddles known as mode stirrers that create the multipath environment. Numbers of small antennas were designed and various kinds of antennas were tested for measurement. The purpose of this paper is to show that the antenna efficiency can be measured accurately in much faster, easier and cost effectively reverberation chamber." } @INPROCEEDINGS{Al-I0511:Mobility, AUTHOR="Ala Al-Fuqaha and Omar Al-Ibrahim and Joe Baird", TITLE="A Mobility Model for {GPS-Based} Encryption", BOOKTITLE="Globecom 2005 Computer \& Network Security", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="Wireless networking is a fast growing market due to recent advances in mobile and wireless technologies. Secure communication between wireless hosts is essential in certain applications and GPS-based encryption complements traditional encryption techniques by restricting the decryption of a message to a particular geographical area and time period. Existing geo-encryption techniques have limited support for mobile nodes. Therefore, we propose a mobility model for existing geo-encryption techniques that allow mobile nodes to exchange movement parameters, so that a sender is able to geo-encrypt messages to a moving decryption zone that contains a mobile nodes estimated location. We also present methods for estimating the mobile nodes movement parameters and discuss the tradeoffs to balance the accuracy of the decryption zone against the frequency of movement updates." } @INPROCEEDINGS{Al-J0509:Performance, AUTHOR="Yaser Al-Jarbou and Uthman Baroudi", TITLE="Performance of Heterogeneous Traffic in Roaming Based Sharing Multi Operator {4G} {WCDMA} Networks", BOOKTITLE="ISWCS 2005 Main Symposium", ADDRESS="Siena, Italy", DAYS=5, MONTH=sep, YEAR=2005, ABSTRACT="Today, sharing radio resources is very important to reduce the cost of network infrastructure. Mobile companies can buy a certain capacity of the shared network depending on their budget and number of subscribers that they can handle. In this way, the subscribers of each operator connect to the same radio access network and can be differentiated through roaming based mechanisms. The analysis of voice traffic and video streaming for shared networks has been discussed in the literature. In this paper, an extended work has been done to study the effect of heavy data traffic like www and ftp on the shared network and how the radio resources with roaming based mechanism may be allocated to the sharing operators. One particular mechanism based on radio resource management (RRM) with preemptive priority queuing in admission control is studies. The results show the effectiveness of the dynamical prioritization mechanism for allocating radio resources to the requested service." } @INPROCEEDINGS{Al-J0511:Multi, AUTHOR="Mohamed Al-Jaafreh and Adel Al-Jumaily", TITLE="Multi Agent System for Estimation of Cardiovascular Parameters", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="Many cardiovascular diseases can be avoided by continuous measuring of cardiovascular parameters. Heart rate, electrocardiogram, blood pressure and pulse wave velocity are the most important and popular cardiovascular parameters. These parameters have been measured by different sensors, which have being developed and improved to achieve reliable, accurate and continuous measurements. This paper presents a new concept to estimate cardiovascular parameters via using a new multi-agent system; that combines two independent methods; first method depends on pulse wave velocity (PWV), while second method depends on heart rate and artery resistance. The outcome of this multi-agent system is a continuous and reliable estimation of cardiovascular parameters by using non-invasive, Cuffless and cheap sensors." } @INPROCEEDINGS{Al-K0504:Parameters, AUTHOR="Amin Al-Ka'bi", TITLE="Parameters Computation of the Modified Loo Mobile Fading Channel", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="In mobile wireless communication systems, the multipath propagation in addition to the movement of the receiver and/or the transmitter leads to drastic and random fluctuations of the received signal. For flat fading channels, the modified Loo model has been proposed as a stochastic model of such received signal fluctuations. In this paper we discuss this stochastic model and an appropriate deterministic model, and subsequently present and analyze simulation results based on these models." } @INPROCEEDINGS{Al-K0505:Mini, AUTHOR="Tariq Al-Khasib and Hussein Alnuweiri and Hossam Fattah and Victor Leung", TITLE="Mini Round Robin: An Enhanced {Frame-Based} Scheduling Algorithm for Multimedia Networks", BOOKTITLE="ICC 2005 Communications QoS, Reliability and Performance Modeling", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="The broad spread of packet data networks and the emergence of applications in multimedia communications, created a driving force towards an improved Quality of Service (QoS) model for todays Internet. A primary component of this model is packet schedulers. We introduce a new frame-based scheduling technique called Mini Round Robin (MRR) that is primarily designed for providing lower latency bounds, and lower start-up latency bound for low-rate but high-priority flows. This enables applications such as Voice-over-IP to demand low delay despite the low reserved bit rate of the voice sessions." } @INPROCEEDINGS{Al-K0506:Fair, AUTHOR="Tariq Al-Khasib and Hussein Alnuweiri and Hossam Fattah and Victor Leung", TITLE="Fair and Efficient {Frame-Based} Scheduling Algorithm for Multimedia Networks", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="The broad spread of packet data networks and the emergence of applications in multimedia communications, created a driving force towards an improved Quality of Service (QoS) model for todays Internet. A primary component of this model is packet schedulers. We introduce a new frame-based scheduling technique called Mini Round Robin (MRR) that is primarily designed for providing lower latency bounds, and lower start-up latency bound for low-rate but high-priority flows. This enables applications such as Voice-over-IP to demand low delay despite the low reserved bit rate of the voice sessions." } @INPROCEEDINGS{Al-K0506:Parameters, AUTHOR="Amin Al-Ka'bi", TITLE="Parameters Computation of the Extended Suzuki Mobile Fading Channel of Type {II}", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="In mobile wireless communication systems, the multipath propagation in addition to the movement of the receiver and/or the transmitter leads to drastic and random fluctuations of the received signal. For flat fading channels, the extended Suzuki process of type II has been proposed as a stochastic model of such received signal fluctuations. In this paper we discuss this stochastic model and an appropriate deterministic model, and subsequently present and analyze simulation results based on these models." } @INPROCEEDINGS{Al-M0511:Recent, AUTHOR="Paul Kwan and Hawlader Al-Mamun", TITLE="Recent Advances in Image Analysis Methods for Protein Spot Identification of {Two-Dimensional} Electrophoresis Gel Images", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="This paper reviews recent advances in image analysis methods for protein spot identification of two-dimensional electrophoresis (2-DE) gel images, which has become an important tool for both differential comparison and overall proteomic analysis. The methods reviewed are related to spot detection, spot matching, and spot quantitation. Our contribution lies in comparing these methods not only by their algorithmic differences, but also on several other criteria including input and output characteristics, the necessity of land-marking for local and/or global gel matching, the potential for large-scale automation, and their adoption in commercial 2-DE image analysis software. This paper is expected to benefit researchers in proteomics by presenting a recent summary of developments in 2-DE gel image analysis." } @INPROCEEDINGS{Al-M0511:Threshold, AUTHOR="Mohammed Hayder Al-Mansoori and Syed Javaid Iqbal and Mohamad Khazani Abdullah and Mohd Adzir Mahdi", TITLE="Threshold Features of {L-Band} Linear Cavity Multiwavelength {Brillouin-Erbium} Fiber Laser", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="Investigation of L-band linear cavity multiwavelength Brillouin-Erbium fiber laser source has been experimentally studied. The effects of Brillouin pump power and wavelength on the threshold pump power are discussed in the paper. We found that there is a limited range for Brillouin pump wavelength to achieve a lasing condition in the laser cavity. Low threshold power of 23.4 mW is obtained from the linear cavity due to highly efficient from both double-pass amplification in the Erbium gain medium and also bidirectional generation of Brillouin Stokes in the single mode fiber." } @INPROCEEDINGS{Al-N0506:Forward, AUTHOR="Tareq Al-Naffouri and Arogyaswami Paulraj", TITLE="A {Forward-Backward} Kalman for the Estimation of {Time-Variant} Channels in {OFDM}", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="OFDM modulation combines the advantages of high achievable rates and relatively easy implementation. However, for proper recovery of the input, the OFDM receiver needs accurate channel information. In this paper, we propose an expectation-maximization (EM) algorithm for joint channel and data recovery. The algorithm makes use of the rich structure of the underlying communication problem- a structure induced by the data and channel constraints. These constraints include pilots, the cyclic prefix, and the finite alphabet constraints on the data, and sparsity, finite delay spread, and the statistical properties of the channel (frequency and time correlation). The algorithm boils down to a forward-backward (FB) Kalman filter. We also suggest a suboptimal modification that is able to track the channel and recover the data with no latency." } @INPROCEEDINGS{AL-Q0511:Space, AUTHOR="Fawaz AL-Qahtani and Zahir Hussain", TITLE="A {Space-Time} {Block-Coded} {PCC-OFDM} Scheme for Flat Fading Wireless Channels", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="This paper presents a transmission scheme joining Polynomial Cancellation Coding OFDM (PCC-OFDM) with Space-Time Block-Coding (STBC). PCC is a coding method for OFDM which maps data onto adjacent subacarriers, used here for reducing the sensitivity of OFDM to carrier frequency offset and Doppler spread. On the other hand, STBC is used to improve the error performance and increase the data rate of the transmission system. Simulation results have shown that the joint application of PCC with OFDM can significantly improve the overall system performance." } @INPROCEEDINGS{Al-S0506:Reducing, AUTHOR="Laith Al-Sulaiman and Hussein Abdel-Wahab", TITLE="{CACMAN:} a Framework for Efficient and Highly Available {CA} Services in {MANETs}", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="MANETs applications and services pose many interesting challenges due to their unique features. Specifically, security is getting a lot attention in every aspect of MANETs due to their inherent vulnerability to attacks. Threats exist in every layer of MANETs stack, and different solutions have been adapted for each security problem. Another problem for MANETs is availability, and adding more resources will not necessarily make the system more available. Certificate Authority (CA) is one of the most important entities in Public Key Infrastructure (PKI) that needs to be designed carefully when adapted to MANETs. The main goal of our work is to provide a framework that addresses the issues of performance and security of CA in MANETs. Additionally, we would like to increase the availability of CA services while lowering packet overhead of the network without increasing the network vulnerability. In this paper, we present a framework suitable for exchanging PKI certificates in MANETs. By caching and exchanging certificates between clients collaboratively, we will show that our system can meet the performance challenges of providing CA service without sacrificing the system security. Using NS-2 Simulator, we have demonstrated the feasibility of the framework, quantitatively, compared to other related research that has addressed the same problem in MANETs environments." } @INPROCEEDINGS{Alam0509:Smart, AUTHOR="Fakhrul Alam and Mursalin Habib and Ayon Quayum and Anindita Talukdar and Sonia Islam and Mashaeikh Hossain", TITLE="Smart Antenna System for {OFDM} based {WLAN}", BOOKTITLE="VTC'F05 Antennas and Propagation", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="Wireless Local Area Network (WLAN) has been one of the great communications technology success stories of the past few years. IEEEs standardization of WLAN has been extended to a family of standards. IEEE 802.11g, based on Orthogonal Frequency Division Multiplexing (OFDM), is a very popular and emerging standard for its capability of high data rate communication up to 54Mbps at the 2.4 GHz Industrial, Scientific and Medical (ISM) band. As the number of consumer devices designed for the ISM band is getting higher, co-channel interference has been identified as the major hindrance to the performance of WLAN devices. In this paper, a method of combating co-channel interference employing smart antenna technique is presented. We employ the Minimum Mean Square Error (MMSE) criterion to perform beamforming. We present simulation results that demonstrate performance improvement at the presence of co-channel interference." } @INPROCEEDINGS{Alam0510:Application, AUTHOR="Md. Shamsul Alam and Md. Mahmudul Hasan and Boshir Ahmed and 0,1,2 Sohail", TITLE="Application of Heuristic {MMKP} in Admission Control and {QoS} Adaptation for Distributed Video on Demand Service", BOOKTITLE="BroadNets 2005 Wireless Networking Symposium", DAYS=3, MONTH=oct, YEAR=2005, ABSTRACT="Allocation and reservation of resources, such as CPU cycles and I/O bandwidth of multimedia servers and link bandwidth in the network, is essential to ensure Quality of Service (QoS) for multimedia services delivered over the Internet. In this paper, we have proposed a new semi-distributed architecture for admission control and QoS adaptation of multimedia sessions to maximize revenue from multimedia services for Distributed Video on Demand System (DVoDS). We have introduced the mapping of Utility Model - Distributed (UM-D) by semi-distributed controller to the Multidimensional Multiple-choice Knapsack Problem (MMKP), a variant of the classical 0-1 Knapsack Problem. An exact solution of MMKP, an NP-hard problem, is not applicable for the online admission control problem in the VoD System. Therefore we have applied heuristic, I-HEU for solving the MMKP for online real-time admission control and QoS adaptation. We have applied the admission control strategy described in the UM-D to the set of Media Server Farms providing streaming videos to users. The performance of semi-distributed architecture applied in a simulated environment over a set of Media Server Farm has been discussed detail using the experimental outcome." } @INPROCEEDINGS{Alam0511:Block, AUTHOR="Mohammad Shah Alam and Shamim Ara Shawkat and Mitsuji Matsumoto", TITLE="Block Based Window Retransmission {ARQ} Scheme for 100Mbit/s Infrared Links", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="With the increase of data transfer rates beyond 100Mbit/s over the infrared links, a robust automatic repeat request (ARQ) scheme is necessary to cope with the high speed environment. At high data rate, the Go-Back-N (GBN) ARQ scheme requires window and frame size adaptation to the corresponding optimum values for the correspondent Bit Error Rate (BER). But adaptive approaches always add a significant amount of complexity to the system. This paper presents a non adaptive Block Based Window Retransmission (BBWR) ARQ scheme that operates with a fixed size receiver buffer and achieves a significant improvement in the throughput efficiency over a wide range of BER at 100Mbit/s infrared links. Simulation results are presented which also reveal the effect of link layer parameters, such as window and frame data length, and physical layer parameters, such as minimum turn around time on the performance of the proposed scheme." } @INPROCEEDINGS{Alan0504:Enhanced, AUTHOR="Olli Alanen and Mikko Paakkonen and Mikko Ketola and Timo {Hämäläinen} and Jyrki Joutsensalo", TITLE="Enhanced admission control solution for multicasting with {DiffServ}", BOOKTITLE="1st EuroNGI Conference on Next Generation Internet Networks - Traffic Engineering", ADDRESS="Rome, Italy", DAYS=18, MONTH=apr, YEAR=2005, ABSTRACT="Multicast admission control in Differentiated Services network is an important but shortly researched subject. We propose a parameter-based admission control method. The method rejects new multicast join requests that would otherwise decrease the quality experienced by the existing receivers. DiffServ network edge nodes filter join requests and generate new requests. The proposed method is developed as an extension to the DSMCast protocol but could also be adapted to other protocols. In this paper the parameter-based admission control is compared to earlier created, measurement-based admission control methods, as well to situation when no admission control is used." } @INPROCEEDINGS{Alav0509:Analysis, AUTHOR="Bardia Alavi and Kaveh Pahlavan", TITLE="Analysis of Undetected Direct Path in Time of Arrival Based {UWB} Indoor Geolocation", BOOKTITLE="VTC'F05 Antennas and Propagation", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="Accurate indoor geolocation using time-of-arrival (TOA) is seriously challenged with the occurrence of undetected direct path (UDP) conditions caused by severe multipath in indoor areas. As a result, analysis of the occurrence of UDP in indoor areas is extremely important for design and performance evaluation of the emerging indoor geolocation systems. A UDP occurs when the received signal strength of the direct path (DP) between the transmitter and the receiver falls below the detection threshold of the receiver, but the total received signal power is still above the threshold. This paper provides a novel analysis for modeling the behavior of the DP and the total received power and uses the model to calculate the probability of UDP occurrence. To verify the accuracy of the analytical model, the results are compared with the empirical UWB measurements in typical indoor areas." } @INPROCEEDINGS{Alav0509:Indoor, AUTHOR="Bardia Alavi and Kaveh Pahlavan and Nayef Alsindi and Xinrong Li", TITLE="Indoor Geolocation Distance Error Modeling using {UWB} Channel Measurements", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="In this paper we introduce a model for the distance error measured from the estimated time of arrival (TOA) of the direct path (DP) in a typical multipath indoor environment. We use the results of our ultra-wideband (UWB) measurement database in a sample office environment. To begin modeling, first we separate the causes of the error into multipath and undetected direct path (UDP), and then we model them separately considering the variation of bandwidth of the system. We show that the behavior of the distance error consists of two parts; one that is from multipath, and the other one from UDP. Both errors can be modeled as Gaussian, so the final distance error is a mixture of two Gaussian distributions. We also related the statistics of the distributions to the bandwidth of the system." } @INPROCEEDINGS{Alay0506:Linear, AUTHOR="Faisal Alayyan and Yee {Hong Leung} and Abdelhak Zoubir", TITLE="Linear one tap equalizer for the spatial diversity based on {GI-less} {OFDM} system", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="In this paper, we introduce pre-FFT and post-FFT equalizers for an OFDM system without using a guard interval. Inter-symbol-interference is significantly reduced by adopting virtual sub-carriers. We extend the idea of spatial diversity to the proposed system to obtain high performance equalization in the presence of additive channel noise. The performance of the proposed equalizers is illustrated by computer simulations" } @INPROCEEDINGS{Alù0504:Sub, AUTHOR="Andrea Alù and Filiberto Bilotti and Nader Engheta and Lucio Vegni", TITLE="A sub-wavelength omni-directional leaky-wave antenna made of a resonant cylindrical metamaterial shell", BOOKTITLE="Loughborough Antennas and Propagation Conference 2005", ADDRESS="Burleigh Court Conference Centre", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="The need for omnidirectional radiators is particularly apparent in cellular and wireless multi-point applications, where the radio-base stations should uniformly cover the azimuthal angles, being directive in the elevation angle towards a preferred direction to cover its own cell without interfering with the neighbouring antennas. A radiator with these properties may be synthesized exploiting the resonant properties of cylindrical metamaterial shells supporting leaky-waves. We show, in fact, analytically how a circularly symmetric resonant material polariton may be supported by a suitably designed sub-wavelength homogenous cylindrical shell of low negative permittivity. Some simulated radiation properties and some physical insights into the phenomenon are provided." } @INPROCEEDINGS{Alba0502:Experimental, AUTHOR="Roberto Albanese and Daniele Francesco Alì and Stefano Giordano and Ugo Monaco and Fabio Mustacchio and Gregorio Procissi", TITLE="Experimental Comparison of Fault Notification and {LSP} Recovery Mechanisms in {MPLS} Operational Testbeds", BOOKTITLE="3rd International Workshop on QoS in Multiservice IP Networks", ADDRESS="Catania (Italy)", DAYS=2, MONTH=feb, YEAR=2005, ABSTRACT="This paper reports on the comparison of recovery strategies in MPLS-TE experimental testbeds. We focus on alternative notification mechanisms and compare different end-to-end recovery techniques. A measurements campaign have been performed in two different trials based on commercial routers and PC/Linux boxes. In the former an inbuilt signaling-based mechanism provides remote fault notification to the edge routers while in the latter a prototype of IGP flooding-based mechanisms have been implemented. We investigate the impact of the alternative fault notification schemes and present a performance evaluation distinguishing different components of the overall recovery time. We believe that the ideas and experimental insight contained in this work will be helpful to other people involved in standardization and implementation of MPLS-related control plane." } @INPROCEEDINGS{Albe0504:MOON, AUTHOR="Guido Albertengo and Claudio Pastrone and Giacomo Tolu", TITLE="{MOON:} a New Overlay Network Architecture for Mobility and {QoS} Support", BOOKTITLE="1st EuroNGI Conference on Next Generation Internet Networks - Traffic Engineering", ADDRESS="Rome, Italy", DAYS=18, MONTH=apr, YEAR=2005, ABSTRACT="The continuously increasing diffusion of mobile devices such as laptops, PDAs and smartphones, all equipped with enhanced functionalities, has led to numerous studies about mobility and to the definition of new network architectures capable to support it. Problems related to mobility have been addressed mostly operating on the network or transport layers of the Internet protocol stack. As a result, most of these solutions generally require modifying the TCP and/or the IP protocol. Although this approach is well suited to handle mobility, it lacks in compatibility with the Internet Protocol Suite. This consideration led us to study a fully TCP compatible and flexible approach we dubbed MOON, for MObile Overlay Network. This network architecture is currently under design at LIPAR, the Internet, Protocols and Network Architecture Lab of Politecnico di Torino." } @INPROCEEDINGS{Albe0507:LOC3, AUTHOR="Andreas Albers and Stefan Figge and Mike Radmacher", TITLE="{LOC3} - Architecture Proposal for Efficient Subscriber Localisation in Mobile Commerce Infrastructures", BOOKTITLE="The 2nd IEEE International Workshop on Mobile Commerce and Services", ADDRESS="Munich", DAYS=18, MONTH=jul, YEAR=2005, ABSTRACT="The following paper proposes a new approach for providing localisation of mobile subscribers. Since various different localisation technologies have entered the mobile mass-market, mobile applications requiring location information are increasingly challenged by the complexity of selecting and accessing appropriate localisation sources. Addressing this development, an integrative platform is proposed, enabling unified access to the most suitable localisation technology by taking into account accuracy, availability and costs. By assembling state-of-the-art localisation technologies to an implementation called LOC3, the feasibility of the outlined architecture approach is proven." } @INPROCEEDINGS{Alco0509:Turbo, AUTHOR="Maria de Lourdes Alcoforado and Valdemar {Rocha Jr.}", TITLE="Turbo Block Codes for the Binary Adder Channel", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="A novel coding scheme for collaborative coding multiple access is introduced for practical application, which permits improving performance with the use of turbo decoding." } @INPROCEEDINGS{Alcu0502:Service, AUTHOR="Luigi Alcuri and Giuseppe D'Acquisto and Giuseppe Barbera", TITLE="Service curve estimation by measurement: an input output analysis of a Softswitch model", BOOKTITLE="3rd International Workshop on QoS in Multiservice IP Networks", ADDRESS="Catania (Italy)", DAYS=2, MONTH=feb, YEAR=2005, ABSTRACT="In this paper, we describe a new method to solve a methodological problem for the analysis of telecommunications systems in packet networks. The basic building block of the framework is the concept of service curve, which defines a general QoS model taking into account both bandwidth and delay requirements. In terms of min-plus theory, a system is characterized by a service curve, which is determined by two parameters: the latency and the allocated rate. Unfortunately, there are no analytical expressions that compute the parameters of a service curve for a non-FIFO and work-conserving systems. Our simulation based approach, instead, can be applied to all these systems and gives an estimate of the service curve in a very simple way, with minimum information about system architecture. We applied this method to a very simple model of a Softswitch node in a NGN telephone service environment. Signaling traffic streams and the dynamic of the system have been reproduced using a commercial simulation tool called Extend. The main result of the work is the selection of a proper rate-latency service curve, which has been proposed by IETF for the characterization of network elements in both IntServ and DiffServ scenarios." } @INPROCEEDINGS{Alda0504:Optimal, AUTHOR="Mansour Aldajani", TITLE="Optimal Placement of Wireless {Base-Stations} Based on {2-D} Convolution", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="In this paper, we introduce a novel approach for solving the placement problem of wireless base-stations on a 2-dimensional space. This approach computes the minimum number of stations as well as their locations such that the area under consideration is covered with a minimum power threshold. The new approach is based on the utilization of 2-dimensional convolution to compute the contribution of each candidate base-station. The proposed placement algorithm provides network designers with flexibility in choosing arbitrary power propagation and demand patterns using a graphical mapping interface. Simulations of the proposed algorithm show its efficiency in solving the placement problem and versatility in terms of the network design options it can provide." } @INPROCEEDINGS{ALDA0511:Knowledge, AUTHOR="David Al-Dabass", TITLE="Knowledge Mining Algorithms using Recurrent Hybrid Inference Networks", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="We present recurrent inference networks to model data collected from physical, biological and chemical processes which exhibit behaviour that can only be accounted for by using dynamical models. These contain nodes that exhibit oscillatory characteristics. Given the behaviour trajectory of such a node it is required to abduct the values of its causal parameters. Hybrid recurrent nets are introduced which consist of a combination of arithmetic nodes and special integrator nodes to represent intelligent systems with dynamics. Several of these hybrid nodes are put together to model the complex behaviour that characterises intelligent systems. To determine the causal parameter a two stage process is devised: the time derivative of the trajectory are determined first, followed by the parameters. Hybrid recurrent nets of first order are employed to compute derivatives continuously as the behaviour is monitored. A further layer of arithmetic and hybrid inference nets is then used to track the values of the causal parameters of the complete model. Applications from hybrid inference nets and signal processing are used to illustrate the techniques." } @INPROCEEDINGS{Alem0505:Interaction, AUTHOR="Tigist Alemu and Yvan Calas and Alain Jean-Marie", TITLE="The Interaction of Forward Error Correction and Active Queue Management", BOOKTITLE="NETWORKING 2005", ADDRESS="Waterloo, Ontario, Canada", DAYS=2, MONTH=may, YEAR=2005, ABSTRACT="This paper studies the interaction of a forward error correction (FEC) code with queue management schemes like Drop Tail (DT) and RED. Since RED spreads randomly packet drops, it reduces consecutive losses. This property makes RED compatible a priori with the use of FEC at the packet level. We show, through simulations, that FEC combined with RED may indeed be more efficient than FEC combined with DT. This however depends on several parameters like the burstiness of the background traffic, the FEC block size and the amount of redundancy in a FEC block. We conclude generally that using FEC is more efficient with RED than with DT when the loss rate is small, a relatively important amount of redundancy and at most a moderate FEC block size is used. We complement these observations with a simple model, which is able to capture the tradeoff between the locality and the frequency of losses." } @INPROCEEDINGS{Alex0504:GAL, AUTHOR="George Alexandris and Gregory Yovanof", TITLE="{GAL} - A Scalable Routing Protocol for Clustered {Ad-Hoc} Networks", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="The ability to operate without fixed infrastructure offers considerable advantages when trying to establish communication under dire or unprofitable terrain circumstances. In those kinds of situations, nodes often move in groups, forming clustered ad hoc networks and creating a different communication framework than networks with uniformly distributed nodes. GAL is a novel scalable scheme designed to meet the routing needs of such applications. Its efficacy has been demonstrated during extensive simulations with networks of varying sizes and dynamics. Comparisons to popular routing protocols highlight the performance advantage and superior bandwidth efficiency of the proposed scheme particularly for larger network topologies." } @INPROCEEDINGS{Alex0505:Emergent, AUTHOR="Mark Alexiuk and Gordon Wiebe", TITLE="Emergent Models of Wellness: A Case Study of Management Practices in Single Resident Occupant Hotels of Vancouver {CA}", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Authors: Mark Alexiuk Gordon K. Wiebe University of Manitoba Community Builders Institute for Biodiagnostics KeyWords: emergence, homelessness, swarm engineering. Contact: Mark Alexiuk 435 Ellice Avenue Institute for Biodiagnostics Winnipeg MB R3B 1Y6 alexiuk(at)ieee.org Phone: (204) 984-8151 Fax: (204) 983-3154 Abstract Emergence is the phenomenon of collective intelligence exhibited by a population of independent agents. The presence of collective intelligence is conditional on certain criteria: population diversity and density are high; interaction levels are high, random and exchange local information; environmental rate of change does not preclude adaptation. Examination of emergent principles is becoming a common framework for exploring salient features of dynamical systems. Visual results allow the researcher to formulate hypotheses on an intuitive level, a key feature of exploratory data analysis (EDA). This framework can provide insight into hitherto intractable problems in sociology and economics. One such problem is defining a mathematical model for homelessness that allows policy evaluation with respect to the holistic wellness of impacted individuals. This paper addresses: 1.Defining a swarm model that abstracts key features of homelessness in municipal areas with single resident occupant (SRO) hotels. 2.Reproducing salient features of a typical population as described by social workers. 3.Suggesting through simulations the effects of various management policies (best practice, market-driven, and de-regulated) upon wellness in sub-categories in the population and the population as a whole. Recent changes in management policies at a series of SRO hotels in Vancouver have produced significant changes to the wellness of its residents. Significantly, the policy changes encouraged bottom-up organization; residents re-acted by quickly forming social networks and asserting ownership in an enhanced living space. The implication proposed is that the criteria regarding population diversity and density, interaction levels and other emergent principles are met within a single SRO or its immediate neighborhood and justify dynamical systems modeling. A series of survey data given at several SRO hotels quantify trends in demographics and individual wellness. Swarm simulations to reproduce this community phenomenon were written in using Scopira®, a visual programming language for C++ algorithm development." } @INPROCEEDINGS{Alex0505:Semiconductor, AUTHOR="Dimiter Alexandrov", TITLE="Semiconductor compound alloys related to {InN} and their application in design of semiconductor lasers", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="The optical properties of the semiconductors InGaN, InAlN, and InN containing oxygen impurities and their application in the design of electron devices are subject of investigation in this paper. The existence of energy pockets is identified for the electrons in both the conduction band and the valence band of the semiconductors given above. It is found that the electron transition between energy pockets of the valence band and energy pockets of the conduction band is allowed if special conditions are satisfied. This phenomenon tunnel absorption occurs if the transition is due to the photon absorption. The existence of excitons formed by electrons located in pockets of the conduction band and holes in pockets of the valence band is identified. The annihilation between both charges gives PL luminescence. Theoretical results for both optical absorption and PL luminescence are obtained for the semiconductors given above and they show good agreements with the experimental data. The obtained results are used in design of active optical media of semiconductor lasers working in the infrared part of the spectrum. Expressions for the quasi-Fermi levels are derived and the conditions for threshold currents are found. The possibility about tuning of the radiated optical waves is discussed." } @INPROCEEDINGS{ALEX0506:Optimization, AUTHOR="Verle Alexandre and Landrault Alexis and Philippe Maurine and Nadine Azemard", TITLE="Optimization Protocol based on Low Power Metrics", BOOKTITLE="International Workshop on Logic and Synthesis 2005", DAYS=8, MONTH=jun, YEAR=2005, ABSTRACT={Optimizing digital designs implies a selection of circuit implementation based on different cost criteria. Post-processing methods such as transistor sizing, buffer insertion or logic transformation can be used for optimizing critical paths to satisfy timing constraints. However most optimization tools are not able to select between the different optimization alternatives and have high CPU execution time. So, in this paper, we propose an optimization protocol based on metrics allowing to characterise a path and to select the best optimization alternative. In this protocol, we used a closed form model of delay in CMOS structures to define metrics for a deterministic selection of the optimization alternative. We define a way to characterize the design space exploration method, defining maximum and minimum delay bounds on logical paths. Then we adapt this method to a {"}constant sensitivity method{"} allowing to size a circuit at minimum area under a delay constraint. This protocol is implemented in an optimization tool (POPS) and validated by comparing on a 0.25µm process, the optimization results obtained on various benchmarks (ISCAS85) to that resulting from an industrial tool.} } @INPROCEEDINGS{Alfa0506:Studying, AUTHOR="Francisco Alfaro-Cortes and José-Luis Sanchez and Jose Duato", TITLE="Studying the Influence of the {InfiniBand} Packet Size to Guarantee {QoS}", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="InfiniBand (IBA) has been proposed as an industry-standard architecture both for I/O server and interprocessor communication. IBA employs a switched point-to-point network, instead of using a shared bus. IBA is being developed by the InfiniBand Trade Association to provide present and future server systems with the required levels of reliability, availability, performance, scalability, and quality of service (QoS). In previous papers we have proposed an effective strategy for configuring the IBA networks to provide users with the required levels of QoS. This strategy is based on the proper configuration of the mechanisms IBA carries to support QoS. Specifically, our methodology configures the InfiniBand Arbitration Tables and uses the different Service Levels and Virtual Lanes that are available, in order to segregate the different traffic flows. Thus, each flow receives the treatment it has previously requested. Moreover, by using our methodology, applications can be assured that their requirements will be satisfied. In this paper, we review the basis of our methodology and we study the influence of the packet size on the QoS guaranteed to the applications." } @INPROCEEDINGS{Algh0505:Cube, AUTHOR="Masoud Alghoniemy and Ahmed Tewfik", TITLE="Cube Decoding", BOOKTITLE="ICC 2005 Signal Processing for Communications", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="A novel lattice decoder called the Cube Decoder (CD) is proposed in this paper. The cube decoder finds the nearest lattice point to the received signal vector inside a hypercube centered at the received vector. The dimensions of the hypercube depends on the modulating lattice. This is achieved by reformulating the detection problem as a bounded-error subset selection (BESS) and solving a binary integer program. In this paper, it is assumed that the channel is known to the receiver. The proposed decoder uses the Lattice Reduction technique to reduce the interference introduced by the channel. Simulation shows that the CD gives near-optimal performance." } @INPROCEEDINGS{Algh0506:Modeling, AUTHOR="Jaafar Alghazo", TITLE="Modeling and Synthesis of a Conventional Floating Point Fused {Multiply-Add} Arithmetic Unit Using {CAD} Tools", BOOKTITLE="International Workshop on Logic and Synthesis 2005", DAYS=8, MONTH=jun, YEAR=2005, ABSTRACT="In this paper, we model a high speed Arithmetic synthesizable Fused Multiply Add Unit (FMA) capable of implement the following operations: Addition/subtraction, Multiplication. With area speed tradeoff limitation, our concentration was on modeling high speed Arithmetic units with moderate area increase. Thus, we concentrated on developing units that share the same hardware. We modeled a high speed arithmetic fused multiply add unit ( ) Capable of addition/subtraction and multiplication. We concentrated on reducing the delay in critical path by identifying the most time consuming operations in the critical path of a basic multiply Add fused unit. CAD tools were used to model our system. Once modeled and synthesized the system was downloaded onto a FPGAs chip. The chip became a stand alone FMA unit capable of implementing the operations mentioned. Synthesis tools were used to evaluate our designs and reports showed that the estimated minimum delay of our designed unit was 112.917ns." } @INPROCEEDINGS{Ali0503:Mobility, AUTHOR="Syed {Hussain Ali} and Victor Leung", TITLE="Mobility Assisted Opportunistic Scheduling for Downlink Transmissions in Cellular Data Networks", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="This paper presents an online opportunistic scheduling algorithm for the downlink transmission in a time-slotted shared wireless network that combines channel fluctuation and user mobility information in the decision rule. The proposed algorithm is based on an ad hoc strategy to balance exploitation and exploration for a nonstationary restless (multi-armed) bandit problem. The algorithm is a general scheduling scheme and adapts well with any utility function for the elastic traffic. For finite-size service demands, the scheme uses less processing time than the max-rate scheduling scheme. Under moderate load conditions, it gives time savings of up to 10\%. For backlogged service demands, the proposed algorithm performs better than the proportional fair algorithm. Simulation results illustrate the usefulness of the proposed scheme for the elastic traffic and moderate load conditions." } @INPROCEEDINGS{Ali0504:Entropy, AUTHOR="Syeed Ali and Derek Morris and Charles Graff", TITLE="{Entropy-Aware} Image Transport Over Energy Limited, {Ad-Hoc} Networks", BOOKTITLE="2005 IEEE Sarnoff Symposium", ADDRESS="Princeton, NJ", DAYS=18, MONTH=apr, YEAR=2005, ABSTRACT="This paper is a work-in-progress report of an investigation into the transport of still images over energy-limited Ad-Hoc networks with the idea of maximizing the end-to-end throughput of image entropy (in the Shannon sense), while minimizing image distortion and the energy consumed by the network, over some mission duration. We report the progress made during the first year of this investigation. This report primarily discusses entropy-aware image routing, a simulation of a MIMO network link using LabVIEW, and energy consumption over the paths through the network. In addition, the report discusses entropy measurement, distortion measurement, and image compression." } @INPROCEEDINGS{Ali0504:MMAC, AUTHOR="Muneeb Ali and Tashfeen Suleman and Zartash Uzmi", TITLE="{MMAC:} A {Mobility-Adaptive,} {Collision-Free} {MAC} Protocol for Wireless Sensor Networks", BOOKTITLE="International Performance Computing and Communications Conference (IPCCC)", ORGANIZATION="IEEE", PUBLISHER="IEEE Computer Society Press", ADDRESS="Phoenix, Arizona, USA", MONTH=apr, YEAR=2005, KEYWORDS="mobility, MAC, sensor networks, medium access control, mobility adaptive, MAC protocol", ABSTRACT="Mobility in wireless sensor networks poses unique challenges to the medium access control (MAC) protocol design. Previous MAC protocols for sensor networks assume static sensor nodes and focus on energye #ciency. In this paper, we present a mobilityadaptive, collision-free medium access control protocol (MMAC) for mobile sensor networks. MMAC caters for both weak mobility (e.g., topology changes, node joins, and node failures) and strong mobility (e.g., concurrent node joins and failures, and physical mobility of nodes). MMAC is a scheduling-based protocol and thus it guarantees collision avoidance. MMAC allows nodes the transmission rights at particular timeslots based on the tra#c information and mobility pattern of the nodes. Simulation results indicate that the performance of MMAC is equivalent to that of TRAMA [1] in static sensor network environments. In sensor networks with mobile nodes or high network dynamics, MMAC outperforms existing MAC protocols, like TRAMA and S-MAC [2], in terms of energye #ciency, delay, and packet delivery.", URL="http://suraj.lums.edu.pk/~muneeb/MMAC.pdf" } @INPROCEEDINGS{Ali0504:Reduced, AUTHOR="Adel Ali and Abdulmohsen Alheraish", TITLE="Reduced Spatial Multiplexing and Diversity Gains due to Ricean Fading and Antenna Correlation in {MIMO} {Channels-A} Review", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="There continues to be substantial interest in wireless communication systems that employ multiple transmit and receive antennas, due to their promise for dramatically increasing the performance and capacity (or, equivalently, spectral efficiency) without requiring bandwidth expansion. The concept of such multiple-input multiple-output (MIMO) wireless systems was pioneered by Foschini and coworkers and developed into the Bell Labs layered space-time (BLAST) architecture, achieving unprecedented wireless spectral efficiencies, ranging from 2040 bit/s/Hz. Even higher spectral efficiencies may be achieved in certain environments when the system design is optimal. In the real world, the performance of wireless MIMO systems can deviate significantly from the ideal performance due to a variety of reasons including inadequate antenna spacing and/or inadequate scattering leading to spatial fading correlation, the presence of a fixed (possibly LOS) component in the channel resulting in Ricean fading, and gain imbalances between the channel elements through the use of polarized antennas. These effects have been shown to have a significant impact on the performance limits of MIMO channels. One of the most important factors which limit MIMO capacity is the correlation between sub-channels of the matrix channel. For a completely uncorrelated matrix channel, the MIMO capacity reaches its maximum and scales roughly linearly as the number of antennas. The correlation between individual receive and/or transmit branches results in capacity reduction. Several models have been used to study and quantify this phenomenon but have always been limited to some specific scenarios. In particular, the one-ring scattering model has been used to derive the lower and upper bounds on the mean MIMO capacity. While providing useful insight, these bounds are limited to the case of one-end (i.e., either Tx or Rx) correlation only. Using the eigenvalue decomposition technique, a more general MIMO capacity analysis in a correlated channel, which is basically a generalization of the earlier work by Telatar, has been reported. Crucial limiting assumptions of the analysis above are that the channel correlation matrix can be factorized into a product of Tx and Rx end correlation matrices (resulting in separate eigenvalues for the Tx and Rx ends) and that the number of antennas is large (ideally infinite). This is not the case in many practically-important scenarios (e.g., indoor or measured channels or any system with a moderate number of antennas). Recently, it has been shown that the capacity of MIMO channels is asymptotically/approximately Gaussian for virtually all numbers of transmitter/receiver antenna elements over both Rayleigh and Rician environments. Extensions of this work to correlated channels have begun to appear rapidly in the literature. It is now well known that MIMO capacity is very sensitive to the presence of spatial fading correlation which may be present at either or both ends of the radio link. In this paper we review the main developments related to the effect of non-ideal propagation conditions on the spatial multiplexing and diversity gains of MIMO systems. Various correlation and fading channel models are reviewed, for small and large number of antennas, various conditions on signal power and various performance criteria." } @INPROCEEDINGS{Ali0505:Distributed, AUTHOR="Najah {Abu Ali} and Hussein Mouftah and Saeed Gazor", TITLE="A Distributed {Bandwidth-Guaranteed} Routing Algorithm for {Point-to-Multipoint} {VPLS} Virtual Connections", BOOKTITLE="ICC 2005 Next Generation Networks for Universal Services", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="Virtual Private LAN Services (VPLS) is a new Layer 2 (L2) Virtual Private Network (VPN), which allows connection of multipoint customers at the same time; Multi-Protocol Label Switching (MPLS) technology is the most popular candidate for implementing VPLS in the core service provider networks because MPLS can support traffic engineering (TE) functionality over the established label switching paths (LSP). However, MPLS supports the TE over Point-to-Point (P2P) LSPs, the functionality and signaling of Point to Multipoint (P2MP) LSPs are not supported in existing MPLS. Therefore, in this paper, we proposed a new on line distributed routing algorithm for supporting QoS bandwidth flow guaranteed TE functionality over the P2MP VPLS connections in the core MPLS networks. The on-line distributed routing algorithm, guarantees the bandwidth QoS requirements of the VPLS connections while it maximizes the number of admitted requests, which is fulfilled by avoiding the critical links of other source-destinations sets. The critical links are identified based on the number of times the link is used to route the source-destinations set traffic, the load over the links, and the expected demands over these links. The proposed algorithm performance is compared to some existing algorithm such as the Widest Shortest Path (WSP) and the Plotkin algorithms. It shows that it outperforms both algorithms by having lower blocking probability." } @INPROCEEDINGS{Ali0505:Grid, AUTHOR="Kashif Ali and Suprakash Datta and Mokhtar Aboelaze", TITLE="Grid Resource Discovery using Small World Overlay Graphs", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT={Computational grids are believed to be an effective and scalable solution to the problem of resource sharing over large, heterogeneous networks of computing devices. Since grids are highly distributed in nature, one of the most challenging problems is the discovery of dynamic resources in a grid. In this paper we use ideas from P2P systems to propose a solution for the problem. Specifically, we classify nodes as consumers and producers, depending on whether they consume or produce more jobs. Our algorithm connects all producer nodes using an overlay network that is a {"}small-world{"} graph (the graph is produced by adding {"}shortcut{"} chords to a circle). The consumer nodes {"}hang off{"} the small world graph. Producer nodes are forced to take part in resource cataloging and discovery. This has three distinct advantages -- first, it prevents {"}freeloading{"} by forcing producers to do useful work; second, it frees the consumers to only do computations; third, the low diameter of the overlay graph ensures that all resources are within a small number of hops. We evaluate the performance of our algorithm using simulation. Unlike other papers, we simulate our algorithm in the well-known network simulator ns-2. This allows us to test our algorithm in the presence of realistic traffic conditions. We use the BRITE package for generating Internet-like topologies for the underlying physical connection graph. We compared the performance of our algorithm with some algorithms from the literature using metrics like the average time to answer the query, average fraction of resource requests that failed, the average number of requests that were dropped and the average number of routing packets passing through each node. Our experiments show that our algorithm performs well with tens of thousands of nodes and significantly outperform existing algorithms.} } @INPROCEEDINGS{Ali0505:Statistical, AUTHOR="Najah {Abu Ali} and Saeed Gazor and Hussein Mouftah", TITLE="Statistical Delay Garantees of {VPLS} Connections over {MPLS} Networks", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="A new service has generated a considerable interest between service providers because it enables them to offer multipoint layer 2 connectivity. The service is known within the ITEF as the Virtual Private LAN Service (VPLS) [1]. The most popular candidate to deploy VPLS is the Multi-Protocol Label Switching (MPLS) [2] core network, as it supports Traffic Engineering (TE) functionality [3]. However, MPLS-TE [4] functionality is limited to point-to-point (P2P) label switched paths (LSP). It does not provide TE functionality over point-to-multipoint (P2MP) LSPs [5], which are necessary for realizing the VPLS virtual connections. This motivated designing a novel algorithm to reserve the required bandwidth link resources to meet the P2MP VPLS QoS requirements. These requirements are the token bucket traffic parameters, the delay bound, and the delay violation probability. The proposed algorithm is an online distributed algorithm based on measuring the delay of the links traffic. The empirical histogram of the measured delay is fitted to a gamma distribution. The novelty of the algorithm is that it maximizes the number of admitted VPLS connections by exploiting the statistical multiplexing over the delay rather than the bandwidth. To our knowledge, all of the Measurement Based Admission Control (MBAC) algorithms found in literature employ statistical multiplexing over bandwidth. The delay statistical multiplexing uses the fact that packets of connections rarely practice their worst case delay because they rarely send burst traffic simultaneously, which helps in reducing the reserved bandwidth. The algorithm distinctly satisfies each VPLS QoS requirements by calculating explicitly the reserved bandwidth required to meet the delay bound and the delay violation probability. Thus, two VPLS connections require same delay bounds and different violation probabilities can be assigned different reserved bandwidths. The simulation results for evaluating the algorithm performance revealed that the algorithm can admit 2-3 times the number of connections a deterministic admission control algorithm can admit. Index Terms: MPLS, VPLS, statistical QoS, point-to-multipoint connections, resource management." } @INPROCEEDINGS{Ali0506:Reduced, AUTHOR="Karim Ali and Fabrice Labeau", TITLE="Reduced Complexity Joint {Source-Channel} Turbo Decoding of Entropy Coded Sources", BOOKTITLE="Canadian Workshop on Information Theory", ADDRESS="Montreal, Quebec", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="In [6], we presented a new joint source channel turbo decoding algorithm for entropy coded sources. The algorithm was based on a Bayesian network representation of the coding chain, and incorporates three types of redundancies, namely the source memory, the residual redundancy of the source coder and the artificial redundancy introduced by the channel coder. The algorithm was shown to yield several decibels in gain in the symbol error rate along with a drastic reduction in computational complexity, when compared with the existing one [5]. Here we present a novel technique that allows for considerable computational savings with virtually no performance losses. The technique essentially entails declaring certain bits known, early on in the iterative process. Experimental results are presented and discussed." } @INPROCEEDINGS{Ali0509:Joint, AUTHOR="Karim Ali and Fabrice Labeau", TITLE="Joint {Source-Channel} Turbo Decoding of Entropy Coded Sources: A Reduced Complexity, Higher Performance Algorithm", BOOKTITLE="VTC'F05 Transmission Technology", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="A new turbo joint source-channel decoding algorithm is presented. The proposed scheme, derived from a Bayesian network representation of the coding chain, incorporates three types of information: the source memory; the residual redundancy of the source coder; and finally the redundancy introduced by the channel coder. Specifically, we modify an existing algorithm by introducing an equivalent graph, that is shown to hold the same state-space while exhibiting far less undirected cycles. A fully consistent solution for joint turbo decoding within the Bayesian networks framework follows. The proposed algorithm is demonstrated to yield considerably better results along with a drastic reduction in computational complexity when compared to the existing one." } @INPROCEEDINGS{Ali0511:Double, AUTHOR="Mas Izyani {Md Ali} and Muhammad Zamzuri {Abdul Kadir} and Asmahanim Ahmad and Mohd Adzir Mahdi", TITLE="{Double-Pass} Discrete Raman Amplifier with {FBG} for Pump Power Optimization and Improved Performance", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="We present a report on the experimental validation of double-pass discrete Raman amplifier based on dispersion compensating fiber and high reflection fiber Bragg grating at pump wavelength. The pump light at 1435 nm is launched in counter-directional to the incoming input signal. The double-pass direction of the signal is achieved through a fiber loop mirror constructed by a circulator. We proved that with the proposed design, it requires only 55\% of the pump power to achieve the same Raman gain compared to the typical single-pass Raman amplifier." } @INPROCEEDINGS{Ali0511:Qos, AUTHOR="Najah {Abu Ali} and Hussein Mouftah and Saeed Gazor", TITLE="{QoS} Guarantees of {Point-to-Multipoint} {VPLS} Connections", BOOKTITLE="Globecom 2005 Autonomic Internet", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="A new service has generated a considerable interest between service providers because it enables them to offer multipoint layer 2 connectivity. The service is known as the Virtual Private LAN Service (VPLS). Each VPLS connection has different QoS requirements such as delay and violation probability bounds which are to be met in isolation from other VPLS connections. However, intensive studies by some researchers of the existing Measurement Based Admission Control (MBAC) algorithms revealed that none of these algorithms where able to meet the distinct violation probability requirements of the connections. This motivated designing a novel algorithm that is capable of reserving resources to distinctly satisfy the desired violation probability and delay bounds of connection QoS requirements. The proposed algorithm is an online distributed algorithm, which is based on measuring the delay of the link traffic. The empirical histogram of the measured delay is fitted to a gamma distribution, which is used to calculate the required bandwidth to be reserved to meet the connections QoS requirements. Intensive simulation is carried out to evaluate the algorithm performance. The results show that the algorithm is capable of meeting the distinct QoS requirements of each connection, while admitting about three times the number of connections a deterministic admission control algorithm can admit." } @INPROCEEDINGS{Alia0505:Power, AUTHOR="Mahmood {Hosseini Aliabadi} and Seyed Ehsan Abdollahi", TITLE="Power Factor Estimation of Reluctance Synchronous Machine Using Artificial Neural Network", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Reluctance synchronous machines (RSM) are used for flywheel energy storage systems. Most flywheel systems discussed in the literature, use a permanent magnet (PM) machine as the motor/alternator. The PM machine is a popular choice due to the high efficiency and high power to weight ratio, but there is a disadvantage that if the magnitude of magnetic field inside a PM exceeds the intrinsic coercivity of the material, the machine gets demagnetized. On the other hand, in RSM there is no concern for demagnetization. Also, a RSM rotor can be entirely constructed from high strength, low cost materials. In this paper, using Vector Field finite element package, direct to quadrature inductance ratio (Ld/Lq) and maximum power factor for different air gap lengths are obtained. Then, back-propagation neural network (BPNN) is adopted to estimate the maximum power factor. At the end finite element results and neural network results are compared with measured data." } @INPROCEEDINGS{Alic0508:Joint, AUTHOR="Mansoor Alicherry and Randeep Bhatia and Li (Erran) Li", TITLE="Joint Channel Assignment and Routing for Throughput Optimization in Multi-radio Wireless Mesh Networks", BOOKTITLE="11th Annual International Conference on Mobile Computing and Networking", ADDRESS="Cologne, Germany", DAYS=28, MONTH=aug, YEAR=2005, ABSTRACT="Multi-hop infrastructure wireless mesh networks offer increased reliability, coverage and reduced equipment costs over their single-hop counterpart, wireless LANs. Equipping wireless routers with multiple radios further improves the capacity by transmitting over multiple radios simultaneously using orthogonal channels. Efficient channel assignment and routing is essential for throughput optimization of mesh clients. Efficient channel assignment schemes can greatly relieve the interference effect of close-by transmissions; effective routing schemes can alleviate potential congestion on any gateways to the Internet, thereby improving per-client throughput. Unlike previous heuristic approaches, we mathematically formulate the joint channel assignment and routing problem, taking into account the interference constraints, the number of channels in the network and the number of radios available at each mesh router. We then use this formulation to develop a solution for our problem that optimizes the overall network throughput subject to fairness constraints on allocation of scarce wireless capacity among mobile clients. We show that the performance of our algorithms is within a constant factor of that of any optimal algorithm for the joint channel assignment and routing problem. In addition our evaluation shows that the performance of our algorithms is much better than the theoretical worst case bounds." } @INPROCEEDINGS{Alih0509:Comparison, AUTHOR="Reza Alihemmati and Amir Ahmad Shishegar and Nasrin Hojjat and Gholamreza Dadashzadeh and Baktash Boghrati and Amirshahed Mehrtash", TITLE="Comparison of the smart antenna architectures for {OFDM-WLAN} systems in a rich multipath environment based on a spatio-temporal channel model", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="The smart antenna technique as a method of improving the physical layer performance of OFDM WLANs is studied. For this purpose, a comparison of the smart antenna architectures for IEEE802.11a WLAN system using pre-FFT and post-FFT array processing with different parameters is represented. Simulations are performed on a new Simulink model for IEEE802.11a system using a spatio-temporal channel modeling which is based on the measured wideband channels in the 5GHz band. Raw bit-error-rate performance for QPSK/16QAM modulations at LOS and NLOS channel scenarios are evaluated and compared." } @INPROCEEDINGS{AliH0509:OFDM, AUTHOR="Ruhallah AliHemmati and Paeiz Azmi and Farokh Marvasti", TITLE="{OFDM} Clipping Distortion Compensation Using an Iterative Method", BOOKTITLE="VTC'F05 General Conference", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="In this paper, an iterative method for reconstruction of band limited signals from nonuniform samples is used for clipping noise cancellation and then it is examined in Rician fading channels. Simulation results show the proposed method can outperform OFDM systems in BER performance point of view." } @INPROCEEDINGS{Alim0505:Area, AUTHOR="Amirhossein Alimohammad and Bruce Cockburn and Christian Schlegel", TITLE="Area-efficient paralle white Gaussian noise generator", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", MONTH=may, YEAR=2005, ABSTRACT="Digital communication systems are often characterized in the presence of \emph{white Gaussian noise} (WGN), and FPGA devices are increasingly used as a prototyping platform for such communication systems. The off-line software generation of WGN and the transfer of noise-corrupted signals through a serial data port to an FPGA board is a very slow process. In order to speed up the noise generation, an area-efficient parallel WGN generator (WGNG) was designed and implemented in an FPGA. The design was based on the Box-muller algorithm: if x1 and x2 are two uncorrelated uniform random variables with range [0,1], the product of the two functions f1(x1)=sqrt{-2ln(x1)} and f2(x2)=cos(2*pi* x2) generates a sample from a zero-mean, unity-variance Gaussian distribution N(0,1). To avoid correlation among the uniform variables, pseudo-random numbers (PNs) are formed using the serial output (SO) of a 52-bit Linear Feedback Shift Register (LFSR) defined by the characteristic polynomial G(x)= x^{52}+x^3+1. In order to implement the 52-bit LFSR on a Xilinx FPGA using flip-flops (where each configurable logic block (CLB) contains only two flip-flops), 26 CLBs are required. Instead of using flip-flops, we have utilized the shift register LUTs (SRL) and, consequently, only two CLBs are required to implement the PN generator. To reduce hardware complexity further, a K-stage non-uniform quantization of f1(x1) is calculated by a recursive partition of the x1 in [0,1] interval. The values are stored in K dedicated Block SelectRAM memories available on the Xilinx FPGAs. To increase the noise generation rate, only an 8-bit PN is generated to address the first LN SelectRAM. If a PN value is ever equal to 0, another PN is generated to address the next LN SelectRAM. This process is controlled using a state machine. Consequently, f1(x1) can be available after 8k clock cycles where k=1...K. Similarly, to match the aspect ratio of the SelectRAM, the f2(x2) function is stored in the 512x8-bit on-chip memory. The computational core of the Box-Muller WGNG is a simple multiply-accumulate (MAC) unit where the sign signal generated by the LFSR selects between the accumulation or subtraction operation. The fully parameterizable WGNG was implemented on a Spartan-II E FPGA. The parameters of the design include the number of quantization levels, the resolution of the fixed-point inputs/output, the aspect ratios of the SelectRAM memories, and the number of accumulation steps. These parameters have been analyzed in simulation using a C language model and then optimized according to the resource configuration on the FPGA to achieve the most accurate noise distribution. Since the implemented WGNG is efficient in its utilization of the FPGA resources, multiple WGNG subsystems can operate in parallel to speed up the noise generation. The outputs of the resulting WGNGs are averaged to obtain the probability density function of the generated samples." } @INPROCEEDINGS{Alir0505:Efficient, AUTHOR="Shahpour Alirezaee", TITLE="An Efficient Preprocessing Block for The {Middle-Age} Persian Manuscripts", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="In this paper, a preprocessing procedure for the middle age document has been proposed. The major problems in the middle age Persian document are line, word and character interference and as well as noise (Fig.1). This means some characters in the upper and lower lines may interfere with under processing line. On the other hand, each character may interfere with the right and left characters. This paper presents a solution procedure for these effects. After global thresholding, an estimate of line width is computed by use of horizontal histogram (Line\_width). The initial baseline candidates are computed from the horizontal histogram peaks. Then the peaks with distance of less than °Line\_width± are merged together and replaced with their average number. In the next stage search is beginning around the estimated baseline and implemented preprocessing procedure will be capable to find the best region for the text line. Numerical results show that proposed method can remove not only the interfered parts of upper and lower lines but also a major parts of noise appeared after thresholding process (Figure 2 and 3). After line segmentation, a connected component method segments interfered and over lied characters (Figure 4). To evaluate the performance of algorithm, method has been tested on 200 pages of the middle age Persian. The results show 97.35\% accuracy on the text line extraction and removing other lines overlaps and 99.5\% accuracy for line segmentation (Table.1)." } @INPROCEEDINGS{Alir0505:Weighted, AUTHOR="Shahpour Alirezaee", TITLE="A Weighted {Pseudo-Zernike} Feature for Face Recognition", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Statistical approaches for feature extraction are very important in pattern recognition for their computational efficiency and use of global information in an image for extracting features. The advantages of considering orthogonal moments are that they are shift, rotation, and scale invariants and are very robust in presence of noise. Among these features, Pseudo-Zernike polynomials are well known and widely used in the analysis of optical systems. Pseudo-Zernike moments can be computed from geometrical and radial moments . In this study, we introduce a weighted Pseudo-Zernike feature for face recognition. Our selected weight function is proportional to the amount of information on each row of face image (Fig. b, c) and conveys the importance characteristic of the related row. By this weight function, we will intensify the rule of high information region, i.e. eyes, nose and lips, on the extracted features. For classification, a 0ne hidden layer feedforward neural network has been trained. To evaluate the performance of the proposed feature, experimental studies are carried out on the ORL database images of Cambridge University. The numerical results show 98.5\% recognition rate (with 70, 146,40 neurons for the input, hidden, and output layers respectively) on the ORL database for the proposed feature while this amount for the original Pseudo-Zernike is 96\%." } @INPROCEEDINGS{Alkh0506:Phase, AUTHOR="Salim Alkhawaldeh and Xiaofeng Wang and Yousef Shayan", TITLE="{Phase-Shift-Based} Layered Linear {Space-Time} Codes", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="In this paper, a new layered space-time coding scheme for flat fading MIMO channels is presented. Based on linear dispersive coding that preserves the channel capacity, the proposed scheme employs phase shifts among input symbols to maximize both diversity and coding gains without loss of mutual information. In addition, this coding scheme provides simple spatial multiplexing (channel layering) through antenna weighting. As a result, a class of linear block space-time codes can be designed to achieve various tradeoffs between performance and spectral efficiency. Simulation results are provided to show the merits of the proposed scheme compared to conventional schemes." } @INPROCEEDINGS{Alla0405:Centralized, AUTHOR="Miriam Allalouf and Yuval Shavitt", TITLE="Centralized and Distributed Approximation Algorithms for Routing and Weighted {Max-Min} Fair Bandwidth Allocation", BOOKTITLE="2005 IEEE Workshop on High Performance Switching and Routing", ADDRESS="Hong Kong, P.R. China", DAYS=12, MONTH=may, YEAR=2005, ABSTRACT="Given a set of demands between pairs of nodes, we examine the Traffic Engineering problem of maximal flow routing and fair bandwidth allocation where flows can be split to multiple paths (e.g., MPLS tunnels). In the past we presented a polynomial solution for this problem but its complexity makes it hard to implement for large problem sizes. Thus, this paper presents a fully polynomial epsilon-approximation (FPTAS) algorithm for the max-min fair allocation problem which is based on a primal-dual alternation technique. In addition we present a fast and novel distributed algorithm where each source router can find the routing and the fair rate allocation for its commodities. We implemented the centralized algorithm to demonstrate its correctness, efficiency, and accuracy." } @INPROCEEDINGS{Alla0505:Use, AUTHOR="Marcel Allain", TITLE="The use of pseudo-random binary sequences to predict a dc-dc converters control-to-ouput transfer function in continuous conduction mode", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="The design of a static converters regulation loop requires prior knowledge of the converters open-loop dynamic characteristics (i.e. control-to-output transfer function). Experimentation using a network analyzer and ac small-signal modeling are presently used to determine these characteristics. Each method has its drawbacks. Experimentation requires prior construction of a prototype circuit before any results can be obtained with the network analyzer. Modeling though quicker than the experimental method is less precise since the resulting linear models representing nonlinear switching circuits are constructed using approximations. Some models are also inadequate because they can only be applicable to certain converter topologies and conduction modes. Ideally, the designer should be able to obtain the converters dynamic characteristics without having to build a prototype or search for the appropriate equivalent small-signal model for a given converter circuit. It should also offer the future possibility of being integrated into a global CAD strategy for the static converter. In this paper, we describe the use of a time-domain simulation using a programmed maximum-length pseudo-random binary sequence to modulate a dc-dc converters duty cycle in order to obtain the converters control-to-output transfer function. A pseudo-random binary sequence is a sequence of rectangular pulses that are modulated in width. Such a sequence can be easily programmed using a shift register. Approximating a discrete-time white noise signal, the sequence provides rich spectral content. Using such a signal, one is able to excite the converters output with different frequencies simultaneously during one time-domain simulation. Another reason why this method is an interesting alternative to existing methods is the fact that a time-domain simulation of a non-linear circuit switching in time will allow us to obtain more accurate results than a frequency response test using a linear model. Some preliminary simulation results are compared to equivalent small-signal models." } @INPROCEEDINGS{Alle0504:Antenna, AUTHOR="Ben Allen", TITLE="Antenna and Propagation Design Challenges for Ultra Wideband Wireless Systems", BOOKTITLE="Loughborough Antennas and Propagation Conference 2005", ADDRESS="Burleigh Court Conference Centre", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="Ultra wideband (UWB) is currently touted as a wire replacement technology, with short range (<10m) applications in mind. It is also being considered for medium range (<100m), power efficient, low data rate applications, as well as for radar. Due to the inherent wideband nature of the signals, new system design challenges become apparent. This paper introduces UWB wireless technology and presents the antennas and propagation design challenges associated with UWB wireless communication systems." } @INPROCEEDINGS{Alle0507:Assessing, AUTHOR="Stuart Allen and Steve Hurley and Vaid Subodh and Roger Whitaker", TITLE="Assessing coverage in wireless mesh networks", BOOKTITLE="MeshNets 2005", DAYS=15, MONTH=jul, YEAR=2005, ABSTRACT="Wireless mesh networks can provide an effective means of providing affordable broadband access to communities. By acting as a repeater, each household subscribed to the network also provides further coverage within the local area, reducing the need for infrastructure. However, since coverage is dependent on the number and location of subscribers, this raises issues concerning the take up necessary to for a network that achieves the desired levels of coverage. In some circumstances it may be necessary to deploy seed nodes to achieve coverage targets. This paper investigates the relationship between take up and the levels of coverage that may be attained in rural and suburban areas. In addition, simulations show the required number of seed nodes for different scenarios." } @INPROCEEDINGS{Alle0511:Designing, AUTHOR="Wayne Allen and Art Martin and Anand Rangarajan", TITLE="Designing and Deploying a Rural {Ad-Hoc} Community Mesh Network Testbed", BOOKTITLE="Fifth International IEEE Workshop on Wireless Local Networks", DAYS=15, MONTH=nov, YEAR=2005, ABSTRACT="Rural communities suffer from a lack of inexpensive high-speed access to the Internet. One approach to high-speed access in these environments is to share a small number of more expensive high-speed connections across the community. A wireless mesh network can provide a low-cost backbone to enable this sharing. While proprietary solutions for community mesh network exist, typically requiring rooftop or other outdoor antenna deployment, we examine the feasibility of constructing a community mesh using a platform constructed using off-the-shelf hardware and software components deployed entirely within the home. We identify several key challenges to construction of such networks: Well known properties and bugs in 802.11 Ad-Hoc mode and US electrical code that may prohibit such deployments. Most importantly, we identify density as the key challenge to community mesh network deployments and suggest hardware and software approaches to improve density and network performance in these networks." } @INPROCEEDINGS{Alme0505:Effect, AUTHOR="Peter Almers and Shurjeel Wyne and Fredrik Tufvesson and Andreas Molisch", TITLE="Effect of Oscillator Phase Noise and Array Calibration Errors on {MIMO} Measurements", BOOKTITLE="Vehicular Technology Conference Spring 2005 Antennas and Propagation", ADDRESS="Stockholm, Sweden", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="This contribution will study the effects of oscillator phase noise and errors of antenna array calibration on MIMO measurements. We investigate the mean square error (MSE) of multipath parameter estimation by the SAGE algorithm and the effect on Shannon's mutual information (channel capacity)." } @INPROCEEDINGS{Almh0511:Mobile, AUTHOR="Jalal Almhana and Zikuan Liu and Vartan Choulakian", TITLE="A Mobile Terminal Location Tracking Model for Personal Communication Systems", BOOKTITLE="IEEE International Workshop on Performance and Management of Wireless and Mobile Networks", DAYS=15, MONTH=nov, YEAR=2005, ABSTRACT="This paper proposes a Markov movement model for mobile terminals in wireless personal communication networks and studies the location registration problem. We formulate the location registration as a Markov decision process and prove that the optimal strategies have threshold structures. To avoid solving the Bellman dynamical programming equations, we propose a single sample path-based algorithm to tune thresholds of the strategies. Since the proposed algorithm uses only one sample path of the system, it can be processed online, which is important for real system implementation." } @INPROCEEDINGS{Aloi0509:Gridsat, AUTHOR="Giovanni Aloisio and Massimo Cafaro and Simone Molendini and Marco Tana and Franco Tommasi and Andrea Tricco", TITLE="{GridSAT:} Grid enabled Satellite Architecture for Reliable Transmissions", BOOKTITLE="International Workshop on Satellite and Space Communications 2005", ADDRESS="Siena, Italy", DAYS=8, MONTH=sep, YEAR=2005, ABSTRACT="Recently, some work pointed out the need to perform multicast in a grid environment. Today reliable multicast protocols show a very good scalability in terms of goodput and network overhead. Nevertheless, these reliable multicast protocols are not able to achieve appreciable performance in terms of goodput. This is a severe limitation for Grid applications indeed. We show in this paper GridSAT, an architecture which integrates Satellite Reliable Distribution Protocol (SRDP), a reliable multicast protocol optimized for grids, with Globus. Main elements of the architecture and a simulation on the overall performance are shown." } @INPROCEEDINGS{Alon0506:Power, AUTHOR="Marina Alonso and Juan-Miguel Martinez and Vicente Santonja and Pedro Lopez and Jose Duato", TITLE="Power Saving in Regular Interconnection Networks Built with {High-Degree} Switches", BOOKTITLE="19th International Parallel and Distributed Processing Symposium", DAYS=3, MONTH=apr, YEAR=2005, ABSTRACT="Nowadays, high-degree switches are available as building blocks of the interconnection network of clusters of PCs. An alternative to take advantage of the high number of switch ports is to connect every pair of switches through not only one but several links (this is known as link trunking in other environments). This extra connectivity can be exploited by using adaptive routing algorithms, thus improving network throughput and reducing network congestion. However with low traffic loads, all the links that compose the trunk link will not be utilized, but this idle links continue consuming power. Power consumption reduction techniques are being applied everywhere in computer systems and the interconnection network is not an exception, as its contribution is not negligible. In this paper, we present a mechanism that dynamically switches on and off network links as a function of traffic. It is specially targeted to those networks where trunk links are used. The mechanism can switch off any link, provided that network connectivity is guaranteed, (i.e. every pair of switches should be connected through at least one active link). Indeed, this restriction makes it possible to use the same routing algorithm regardless the power saving actions taken, thus simplifying router design. Our simulation results show that the network power consumption can be greatly reduced, at the expense of some increase in latency. Nevertheless, it is shown that the power reduction is always higher that this latency increase." } @INPROCEEDINGS{Alon0509:Oportunistic, AUTHOR="Luis Alonso and Alex Cateura and Christos Verikoukis", TITLE="Oportunistic Schedulling for {WLAN} systems using {Cross-Layer} Tecniques and a Distributed {MAC}", BOOKTITLE="VTC'F05 Wireless Access", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="Although a variety of Medium Access Control (MAC) schemes have been designed for wireless systems in order to manage the radio frequency spectrum resource and to provide certain Quality of Service (QoS) requirements to mobile users, the efficiency of such systems can be optimised when considering some vertical coupling between layers. This paper analyses, by means of simulations, the performance of a Distributed Queuing Collision Avoidance (DQCA) MAC protocol for wireless local area networks, including Cross-Layer concepts in order to optimise radio channel utilization. DQCA is a distributed always-stable high-performance protocol that behaves as a random access mechanism under low traffic conditions switching smoothly and automatically to a reservation scheme when traffic load goes up. Preliminary results show that, even DQCA itself can improve significantly the performance of a WLAN system, it can be further enhanced in terms of throughput and mean packet delay when deeper Cross-Layer concepts are used in order to schedule packet transmissions." } @INPROCEEDINGS{Alou0503:Quasi, AUTHOR="Sara Alouf and Eitan Altman and Jerome Galtier and Jean-François Lalande and Corinne Touati", TITLE="Quasi-optimal bandwidth allocation for multi-spot {MFTDMA} satellites", BOOKTITLE="IEEE INFOCOM 2005", ADDRESS="Miami", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="This paper presents an algorithm for resource allocation in satellite networks. It deals with planning a time/frequency plan for a set of terminals with a known geometric configuration under interference constraints. Our objective is to maximize the system throughput. while guaranteeing that the different types of demands are satisfied, each type using a different bandwidth. The proposed algorithm relies on two main techniques. The first generates admissible configurations for the interference constraints, whereas the second uses mixed linear/integer programming with column generation. The obtained solution estimates a possible allocation plan with optimality guarantees, and highlights the frequency interferences which degrade the construction of good solutions." } @INPROCEEDINGS{Alou0509:Minimum, AUTHOR="Mohamed-Slim Alouini and Hong-Chuan Yang", TITLE="Minimum Estimation and Combining Generalized Selection Combining {(MEC-GSC)}", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="This paper introduces a new adaptive minimum-estimation minimum-combining switched-combining based scheme that reduces considerably the average receiver channel estimation complexity and the power drain from the battery while satisfying the desired performance requirement. More specifically, analysis supported by numerical results show that the newly proposed combining scheme can achieve essentially the same performance as competing schemes such as generalized selection combining (GSC) and minimum selection GSC while offering 50 \% channel estimation 75 \% and processing power savings for some system parameters of interest." } @INPROCEEDINGS{Alou0509:Switched, AUTHOR="Mohamed-Slim Alouini", TITLE="{Switched-Based} Reduced Feedback {OFDM} Multi-user Opportunistic Scheduling", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="We consider in this paper the problem of opportunistic scheduling of users employing OFDM with adaptive modulation and coding under the constraint that all sub-carriers are assigned to a single user during one time slot. We first present an optimal scheme which schedules the user with the best instantaneous channel conditions in order to maximize the system sum-capacity. The optimality of this scheme comes at the expense of a full feedback load and high number of channel estimations. In an attempt at simplifying the complexity of the system, we then present and study the performance of two switched-based scheduling schemes. Extensive and detailed numerical results are performed to illustrate the capacity-feedback tradeoff of the three schemes under consideration. These results show the switched-based scheduling schemes reduce considerably the number of channel estimations and the feedback load with a negligible loss in sum-capacity." } @INPROCEEDINGS{Alpc0504:Power, AUTHOR="Tansu Alpcan and Xingzhe Fan and Tamer Basar and Murat Arcak and John Wen", TITLE="Power Control for Multicell {CDMA} Wireless Networks: A Team Optimization Approach", BOOKTITLE="3rd International Symposium on Modeling and Optimization in Mobile,Ad-hoc and Wireless Networks", ADDRESS="Riva del Garda, Trentino, Italy", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="We study power control in multicell CDMA wireless networks as a team optimization problem where each mobile attains its individual fixed target SIR level by transmitting with minimum possible power level. We derive conditions under which the power control problem admits a unique feasible solution. Using a Lagrangian relaxation approach similar to the one in [1] we obtain two decentralized dynamic power control algorithms: primal and dual power update, and establish their global stability utilizing both classical Lyapunov theory and the passivity framework [2]. We show that the robustness results of passivity studies [3][4] as well as most of the stability and robustness analyses of the framework [1] in the literature are applicable to the power control problem considered. In additon, some of the basic principles of call admission control are investigated from the perspective of the model adopted in this paper. In the fuller version, we will illustrate the proposed power control schemes through simulations." } @INPROCEEDINGS{Alpi0506:XML, AUTHOR="Pedro Alipio and Solange Lima and Paulo Carvalho", TITLE="{XML} Service Level Specification and Validation", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="This paper addresses the problem of formalizing Service Level Specifications (SLSs) as a first step to simplify and automate the configuration and management of multiservice IP networks. A formal representation SLSs will allow their automatic validation and processing, fostering the dynamic negotiation of SLSs and the interoperability among service management entities. In this way, taking advantage of XML characteristics such as extensibility and portability a Schema is presented describing XML SLSs sections and their contents. In addition, an XML validator utility was built to check if SLSs are correctly specified. An XML SLS for an IP telephony service is used to exemplify this proposal expressiveness." } @INPROCEEDINGS{Alsa0504:Energy, AUTHOR="Waleed Alsalih and Selim Akl and Hossam Hassanein", TITLE="{Energy-Aware} Task Scheduling: Towards Enabling Mobile Computing over {MANETs}", BOOKTITLE="5th IEEE International Workshop on Algorithms for Wireless, Mobile, Ad Hoc and Sensor Networks", ADDRESS="Denver, Colorado", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="Enabling high performance, persistent mobile computing has recently become a very active research area. The widespread popularity of mobile computing devices, such as laptops, handheld devices and cell phones, as well as the recent advances in wireless communication technologies are the principal motivators of this research area. However, battery energy limitation is the main challenge towards enabling persistent mobile computing. Several hardware-based techniques have been proposed; this has led to more energy-efficient systems. Nevertheless, the problem still remains and there is a consensus that software-based techniques have the potential to reduce energy demand and contribute to solve the problem. In this paper, we look into the problem of distributing computational tasks amongst a set of mobile computing devices in a Mobile wireless Ad hoc NETwork (MANET) in such a way that conserves energy and improves performance. In such a distributed environment, the assignment of computational tasks to different devices and the order of their execution play a vital role in energy conservation and performance improvement. The main contributions of this paper are formulating a novel energy-aware scheduling problem and proposing a heuristic algorithm to solve it. Our scheduling algorithm schedules a set of computational tasks, which may have dependencies and communication, into a set of heterogeneous processors in such a way that minimizes both the total consumed energy and the makespan (i.e., the time by which all tasks complete their execution). Experiments show that significant improvement can be achieved by using our scheduler." } @INPROCEEDINGS{Alsh0506:Avoid, AUTHOR="Naif Alsharabi", TITLE="Enhance On-demand Ad-hoc network Performance Using Packets Received Time Prediction", BOOKTITLE="Multimedia Wireless Access Network on fixed Network", ADDRESS="Orlando, Florida", MONTH=jun, YEAR=2005, KEYWORDS="PRT , Packets Received Time, Naif Al-sharabi , AODV, DSR, Wireless, Ad-hoc", ABSTRACT="Abstract: Most existing on-demand mobile ad hoc network routing protocols continue using a route until a link breaks. During the route reconstruction, packets can be dropped, which will cause significant throughput degradation. In this paper we introduce the Packets Received Time (PRT) to predict the link state, that is, if a particular node is soon to go out of transmission range. The Prediction Algorithm together with our PRT approach enhances the performance of the existing Ad-hoc On-Demand Distance Vector (AODV) protocol. The new approach is compared with original AODV in CBR and TCP traffics using various scenarios. The simulation results showed that our scheme is more efficient, reliable and improves throughput of the Ad-hoc network." } @INPROCEEDINGS{Alsu0509:Impact, AUTHOR="Emad Alsusa and Mohammed Baidas and Yeonwoo Lee", TITLE="On the Impact of Efficient Power Allocation in Pilot Based Channel Estimation Techniques for Multicarrier Systems", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="The use of pilot signals for the purpose of channel estimation in multicarrier systems does not only consume bandwidth but also signal power that could otherwise be invested in the information symbols to be transmitted. The aim of this paper is to investigate the issue of optimal transmitter power distribution between the pilot and information signals and evaluate its impact on the performance of multicarrier systems. It will be shown that the optimal power distribution is primarily influenced by the ratio of number of pilots to the total number of subcarriers used. An optimal pilot power allocation as a function of this ratio will be proposed for both MPSK and MQAM systems taking into account channel estimation errors." } @INPROCEEDINGS{Alth0509:UWB, AUTHOR="Frank Althaus and Florian Troesch and Armin Wittneben", TITLE="{UWB} {Geo-Regioning} in Rich Multipath Environment", BOOKTITLE="VTC'F05 Transmission Technology", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="Ultra-Wideband provides high resolution of the multipath components of the propagation channel. Therefore a channel impulse response obtained from a certain transmitter can be seen as a signature of its position. This work investigates the possibility to perform rough localization in rich multipath environment by means of those signatures. We refer to geo-regioning as the intention to associate a received signature to a certain region in a room. A measurement campaign is performed collecting a number of 39600 signatures in 22 regions. By means of the measured data the performance of the geo-regioning approach is demonstrated. A simple geo-regioning algorithm is proposed and the impact of important algorithm parameters is pointed out." } @INPROCEEDINGS{Altm0503:Fairness, AUTHOR="Eitan Altman and Konstantin Avrachenkov and Balakrishna Prabhu", TITLE="Fairness in {MIMD} Congestion Control Algorithms", BOOKTITLE="IEEE INFOCOM 2005", ADDRESS="Miami", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="We study fairness among sessions sharing a common bottleneck link, where one or more sessions use a multiplicative increase multiplicative decrease (MIMD) algorithm. Losses or congestion signals occur when the capacity is reached but could also be initiated before that. Both synchronized as well as non-synchronized losses are considered. In the non-synchronized case, only one session suffers a loss at a time. Two models are then considered to determine which source looses a packet: a rate dependent model in which the loss probability of a session is proportional to its rate at the congestion instant, and the independent loss rate model. We first study how two MIMD sessions share the capacity in the presence of general combinations of synchronized and non-synchronized losses. We show that, in the presence of rate dependent losses, the capacity is fairly shared whereas rate independent losses provides high unfairness. We then study inter protocol fairness: how the capacity is shared in the presence of synchronized losses among sessions some of which use additive increase multiplicative decrease (AIMD) protocols whereas the others use MIMD protocols." } @INPROCEEDINGS{Altm0503:Performance, AUTHOR="Eitan Altman and Konstantin Avrachenkov and Arzad Kherani and Balakrishna Prabhu", TITLE="Performance Analysis and Stochastic Stability of Congestion Control Protocols", BOOKTITLE="IEEE INFOCOM 2005", ADDRESS="Miami", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="We study an Adaptive Window Protocol (AWP) with a general increase and decrease profile in the presence of window dependent random losses. We derive a steady-state Kolmogorov equation and obtain its solution in analytic form. We obtain some stochastic ordering relations for a protocol with different bounds on window. A closed form necessary and sufficient stability condition using the stochastic ordering for the window process is established. Finally, we apply the general results to particular TCP versions such as New Reno TCP, Scalable TCP and HighSpeed TCP. We observe that HighSpeed TCP can be used to approximate almost any kind of window behavior by varying only one design parameter." } @INPROCEEDINGS{Altm0503:Stochastic, AUTHOR="Eitan Altman", TITLE="On stochastic recursive equations and infinite server queues", BOOKTITLE="IEEE INFOCOM 2005", ADDRESS="Miami", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="The purpose of this paper is to investigate some performance measures of the discrete time G/G/$\infty$ queue under a general arrival process. We assume more precisely that at each time unit a batch with a random size may arrive, where the sequence of batch sizes need not be i.i.d. All we request is that it would be stationary ergodic and that the service duration has a phase type distribution. Our goal is to obtain explicit expressions for the first two moments of number of customers in steady state. We obtain this by computing the first two moments of some generic stochastic recursive equations that our system satisfies. We then show that these class of recursive equations allow to solve not only the $G/PH/\infty $ queue but also a network of such queues. We finally investigate the process of residual activity time in a $G/G/\infty$ queue under general stationary ergodic assumptions, obtain the unique stationary solution and establish coupling convergence to it from any initial state. Keywords: Stochastic processes/Queueing theory." } @INPROCEEDINGS{Altm0505:Particle, AUTHOR="Zwi Altman and Hervé Dubreil and Jean-Marc Picard and Maurice Clerc", TITLE="Particle swarm optimization of fuzzy logic controller for high quality {RRM} auto-tuning of {UMTS} networks", BOOKTITLE="Vehicular Technology Conference Spring 2005 Wireless Access", ADDRESS="Stockholm, Sweden", DAYS=28, MONTH=may, YEAR=2005, ABSTRACT="Auto-tuning of Radio Resource Management (RRM) parameters using Fuzzy Logic Controllers (FLCs) has been introduced to enhance UMTS network performance and adapt it to traffic variations. This paper presents a methodology for optimizing the performance of FLC based auto-tuning tasks, by adapting the controller to different traffic characteristics and network environments. The Particle Swarm (PS) optimization approach is utilized to guide the auto-tuning optimization process. Results for admission control and macrodiversity FLC optimization illustrate the effectiveness of the proposed methodology." } @INPROCEEDINGS{Altm0505:Slotted, AUTHOR="Eitan Altman and Dhiman Barman and Abderrahim Benslimane and Rachid El-Azouzi", TITLE="Slotted Aloha with priorities and random power", BOOKTITLE="NETWORKING 2005", ADDRESS="Waterloo, Ontario, Canada", DAYS=2, MONTH=may, YEAR=2005, ABSTRACT="We study distributed choice of retransmission probabilities in slotted Aloha under power differentiation. We consider random transmission powers and further study the role of priorities (through power control) given either to new arriving packets or to backlogged ones. We study both the cooperative team problem in which a common objective is jointly optimized as well as the noncooperative game problem. We show that the new proposed schemes not only improve the average performances considerably but are also able in some cases to eliminate the bi-stable nature of the slotted Aloha." } @INPROCEEDINGS{Altu0505:Rate, AUTHOR="Hulya Seferoglu and Yucel Altunbasak and Ozgur Gurbuz and Ozgur Ercetin", TITLE="Rate Distortion Optimized Joint {ARQ-FEC} for {Real-Time} Wireless Multimedia", BOOKTITLE="ICC 2005 Multimedia Communication and Home Networking", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="In this paper, we investigate rate distortion optimized streaming of H.264 coded video sequences over time- varying wireless channels. Our objective is to minimize average end-to-end distortion to satisfy a certain Quality of Service (QoS) by considering such media and channel characteristics as packet importance, packet dependencies, decoding deadlines, channel state information and channel capacity. In particular, we propose a sender-driven joint ARQ-FEC method that decides on packet transmissions and re-transmissions as well as the FEC rate used in each transmission. The joint ARQ-FEC method along with packet scheduling aims to minimize the expected video distortion under the given capacity constraints. The simulation results demonstrate the efficacy of the proposed algorithm over the classical error recovery method." } @INPROCEEDINGS{Alut0509:Towards, AUTHOR="Mikko Alutoin and Jeroen Hoebeke and Luis Sanchez and Djamal Zeghlache", TITLE="Towards Self-organising Personal Networks", BOOKTITLE="First International ACM Workshop on Dynamic Interconnection of Networks 2005", ADDRESS="Cologne, Germany", DAYS=2, MONTH=sep, YEAR=2005, ABSTRACT="Personal Network (PN) is an emerging concept which combines pervasive computing and strong user focus. The idea is that the user's personal devices organise themselves in a secure and private personal network transparently of their geographical location. This paper studies a PN architecture where devices form clusters using shared key cryptography over short range radio links (or a local area network) and where the otherwise isolated clusters are interconnected over the IP infrastructure using dynamic tunnelling. True self-organisation of the clusters requires master election. Remarks on the linkage between the different master election algorithms and the ad hoc routing schemes are provided." } @TECHREPORT{Alva0504:K, AUTHOR="Jose Alvarez-Hamelin and Luca Dall'Asta and Alain Barrat and Alessandro Vespignani", TITLE="k-core decomposition: a tool for the visualization of large scale networks", TYPE="arXiv report", INSTITUTION="arXiv", NUMBER="cs.NI/0504107", MONTH=apr, YEAR=2005, ABSTRACT="We use the k-core decomposition to visualize large scale complex networks. This decomposition, based on a recursive pruning of the least connected vertices, allows to disentangle the hierarchical structure of networks by progressively focusing on their central cores. By using this strategy we develop a general visualization algorithm that can be used to compare the structure of various networks and highlight their hierarchical structure. The low computational complexity of the algorithm O(n), where n is the size of the network, makes it suitable for the visualization of very large networks. We apply the proposed visualization tool to several real and synthetic graphs, showing its utility in finding specific structural fingerprints of computer generated and real world networks.", URL="http://arxiv.org/abs/cs/0504107" } @INPROCEEDINGS{Alva0509:Joint, AUTHOR="Marcos {Álvarez Díaz} and Massimo Neri and Carlos Mosquera and Giovanni Emanuele Corazza", TITLE="Joint Precoding and Predistortion Techniques for Satellite Telecommunication Systems", BOOKTITLE="International Workshop on Satellite and Space Communications 2005", ADDRESS="Siena, Italy", DAYS=8, MONTH=sep, YEAR=2005, ABSTRACT="The wide adoption of precoding techniques in terrestrial DSL systems as a means of counteracting channel dispersion has spurred the interest for the application of such techniques to other fields such as Multi-Antenna and Multi-User communications. In parallel, satellite overlay networks have shown to be able to deliver multimedia content both to rural and urban environment. In the latter case, the adoption of Intermediate Module Repeaters (IMRs) is in order so as to complement the direct path in Non Line-of-Sight propagation conditions. The introduction of IMRs increases diversity, but involves also strong time dispersions, which must be properly taken into account. This paper focuses on the application to satellite transmission of Precoding techniques, considering nomadic users both in rural and urban propagation environment. Precoding is known to increase the dynamic range of the processed signal, increasing the stimulation of the non-linear characteristics of an on-board High Power Amplifier (HPA). Typical satellite HPAs are Travelling Wave Tube Amplifiers (TWTA), which are characterised by strong amplitude and phase non-linear distortion when operating close to saturation. The paper studies the sensitivity of the precoded signal to the effects of the HPA, and proposes a valid countermeasure to this impairment: fractional predistortion techniques are adopted to pre-condition the signal entering the HPA, and the related benefit is assessed. The chosen precoding technique is Zero-Forcing Tomlinson-Harashima Precoding (ZF-THP). The results are compared with the performance of an alternative setup using predistortion at the transmitter side and standard ZF-Decision Feedback Equalization (ZF-DFE) at the receiver side." } @TECHREPORT{Alva0510:Architectural, AUTHOR="Jose Alvarez-Hamelin and Aline Viana and Marcelo Amorim", TITLE="Architectural Considerations for a {Self-Configuring} Routing Scheme for Spontaneous Networks", TYPE="arXiv report", INSTITUTION="arXiv", NUMBER="cs.NI/0510082", MONTH=oct, YEAR=2005, ABSTRACT="Decoupling the permanent identifier of a node from the node's topology-dependent address is a promising approach toward completely scalable self-organizing networks. A group of proposals that have adopted such an approach use the same structure to: address nodes, perform routing, and implement location service. In this way, the consistency of the routing protocol relies on the coherent sharing of the addressing space among all nodes in the network. Such proposals use a logical tree-like structure where routes in this space correspond to routes in the physical level. The advantage of tree-like spaces is that it allows for simple address assignment and management. Nevertheless, it has low route selection flexibility, which results in low routing performance and poor resilience to failures. In this paper, we propose to increase the number of paths using incomplete hypercubes. The design of more complex structures, like multi-dimensional Cartesian spaces, improves the resilience and routing performance due to the flexibility in route selection. We present a framework for using hypercubes to implement indirect routing. This framework allows to give a solution adapted to the dynamics of the network, providing a proactive and reactive routing protocols, our major contributions. We show that, contrary to traditional approaches, our proposal supports more dynamic networks and is more robust to node failures.", URL="http://arxiv.org/abs/cs/0510082" } @TECHREPORT{Alva0511:K, AUTHOR="Ignacio Alvarez-Hamelin and Luca Dall'Asta and Alain Barrat and Alessandro Vespignani", TITLE="k-core decomposition: a tool for the analysis of large scale Internet graphs", TYPE="arXiv report", INSTITUTION="arXiv", NUMBER="cs.NI/0511007", MONTH=nov, YEAR=2005, KEYWORDS="Networking and Internet Architecture", ABSTRACT="We use the $k$-core decomposition, based on a recursive pruning of the least connected vertices, to study large scale Internet graphs at the Autonomous System level. This approach allows the characterization of progressively central cores of networks, conveniently uncovering hierarchical and structural properties. Internet maps show the noticeable property of having all $k$-cores consisting of a single connected component with invariant statistical properties (degree distribution, correlation spectrum etc.). This feature suggests that the Internet is organized in a defined hierarchy of connected subgraphs of increasing centrality with self-similar properties. The $k$-core decomposition provides also an interesting tool to follow the temporal evolution of Internet maps and test the stability and reliability of different mapping strategies.", URL="http://arxiv.org/abs/cs/0511007" } @ARTICLE{Alve0511:Specifying, AUTHOR="Jim Alves-Foss and Lu'ay Wahsheh", TITLE="Specifying and Enforcing a {Multi-Policy} Paradigm for High Assurance Embedded Systems", JOURNAL="Journal of High Speed Networks, Special issue on Security Policy Management", DAYS=1, MONTH=nov, YEAR=2005, ABSTRACT={One fundamental key to successful implementation of secure high assurance computer systems is the design and implementation of security policies. For systems enforcing multiple concurrent policies, the design and implementation is a challenging and difficult task. To simplify this task, we present an Inter-Enclave Multi-Policy (IEMP) paradigm for information access of the Multiple Independent Levels of Security and Safety (MILS) approach to high assurance system design for security- and safety-critical embedded systems. The IEMP paradigm manages multiple security policies (i.e., controlling the conflicts and cooperation of policies of different enclaves) within heterogeneous systems. IEMPs are {"}policies about policies{"} that ensure the enforcement of end-to-end mandatory information flow security policies, where the management and evolution of policies can be separated from applications. Although the approach was initially designed for use in the MILS architecture, based on the concept of a separation kernel, it is applicable to a much broader range of architectures.} } @INPROCEEDINGS{Alza0505:Special, AUTHOR="Tara Alzahawi and Mohindar S. Sachdev and Rama Gokaraju", TITLE="A Special Protection Scheme for Voltage Instability Prevention", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Abstract It has become a practice to operate power systems close to their capabilities for economic reasons. More recently, deregulation has further increased the desire and need for operating power systems closer to their capacities. One of the consequences has been that voltage instability is being experienced more often as is evident from major outages experienced in the world during the previous couple of years. Voltage instability is closely related to the maximum load-ability of a transmission network. It is, therefore, important that closeness of the transmission to maximum loading be tracked and actions be taken to reduce the energy flows if the system is operating are close to the load-ability limits. The energy flows on the transmission system depend on the network topology, generation and loads, and on the availability of sources that can generate reactive power. It is essential to monitor power systems to prevent the occurrences of voltage collapse and determine how close they are from experiencing voltage collapse. One of the methods used for this purpose is the Voltage Instability Predictor (VIP). This relay measures voltages at a substation bus and currents in the circuit connected to the bus. From these measurements, it estimates the Thévenins equivalent of the network feeding the substation and the impedance of the load being supplied from the substation. The voltage instability occurs when the magnitude of the Thévenins equivalent impedance of the source is equal to the magnitude of the load impedance (maximum power transfer theorem). This paper describes an extension to the VIP technique in which measurements from adjoining system buses and anticipated change of load are taken in to consideration. This provides a definite advantage over the traditional VIP technique because the closeness to voltage collapse depends on the present operating state as well as the changes likely to happen in the future. Contact information: taa584(at)mail.usask.ca sachdev(at)sasktel.net rama.krishna(at)usask.ca" } @INPROCEEDINGS{Amad0505:Overview, AUTHOR="Mamane Moustapha {Dodo Amadou} and Maarouf Saad and Hamadou Saliah-Hassane", TITLE="{E-Control} Methods to Access Remote Experimental Setup with {LabVIEW} Internet Tools", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="In the last few years Internet continues to become more and more integrated into education. Particularly now Internet is used by students to perform experiments remotely. There are some methods to interact with remote experimental setup. Each of them has his advantages and drawbacks. This paper presents E-Control methods to access remotely physical apparatus for real-time experimentation in control engineering laboratory. The described methods are compared according to the following criterion: required software, flexibility, offering responsibilities, and sharing applications. LabVIEW, a development environment based on graphical programming offers tools for remote monitoring and control over the Web. This software is used to illustrate each method by designing an application for remote speed control of a DC motor. Key words: Control, flexibility, offering responsibilities, sharing, software." } @INPROCEEDINGS{Aman0505:Case, AUTHOR="Nahid Amani and Mahmood Fathy and Mehdi Dehghan", TITLE="A {Case-Based} Reasoning Method for Alarm Filtering and Correlation in Telecommunication Networks", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Alarm Correlation will play an important role in improving the service and reliability in modern telecommunication networks. As the network grows in size and complexity, the supervisors of network are finding it increasingly difficult to cope with the volume of alarm messages produced even from a single network fault. In this paper, a new using Case-Based Reasoning method for alarm correlation in telecommunication networks has been developed. The proposed method has been simulated by developing three main modules: a module for generating faults and alarms, a module for defining network configuration, and a module for Alarm filtering and correlation by using Case-Based Reasoning. One of the most important aspects of the obtained results was the speed of the system. Because of its simplicity, the Case-Based Reasoning model is fast, requiring only a few floating-point calculations to produce the result. The accuracy of alarm correlation achieved in the simulation was higher than 90\% in the case of unavailability of the required cases." } @INPROCEEDINGS{Aman0509:Forward, AUTHOR="Yoshiaki Amano", TITLE="Forward Link Beamforming Performances of {FDD-SDMA} Packet Cellular Testbed System", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="We carried out field trials of the developed FDD-SDMA packet cellular testbed system and demonstrated the effectiveness of the proposed forward link beamforming algorithm. Our forward link beamforming algorithm use not only unidirectional access terminal estimation but also angular spread estimation, where this is the proposed method and available to extract angular spread characteristics from a correlation matrix accumulated with reverse link signals through eigen decomposition. During the field trials, we confirmed that the CIR performance per access point of the proposed forward link beamforming algorithm exceeded that of the beam-steering algorithm in the direction of the access terminal estimation only and were convinced of the effectiveness of the proposed algorithm in a real propagation environment with angular spread." } @INPROCEEDINGS{Amar0404:Control, AUTHOR="Said Amari and Isabelle Demongodin and Jean Jacques Loiseau", TITLE="Control of temporal constraints based on dioid algebra Control of temporal constraints based on dioid algebra for timed event graphs", BOOKTITLE="Workshop on Parallel and Distributed Real-Time Systems", ADDRESS="Denver, Colorado", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="We consider a class of controlled timed event graphs subject to strict temporal constraints. Such a graph is deterministic, in the sense that its behavior only depends on the initial marking and on the control that is applied. As it is well-known, this behavior can be modelled by a system of difference equations that are linear in the Min-Plus algebra $(\mathbb{R}\cup \{ +\infty \} , \mathrm{min}, \mathrm{plus})$. The temporal constraint is represented by an inequation, that is also linear in the min-plus algebra. Then, a method for the synthesis of a control law ensuring the respect of the constraint is described. Two sufficient conditions are given, in terms of the initial tokens and delays along the graph. We give explicit formulas characterizing a control law, which, if the conditions are satisfied, ensures the validity of the temporal constraints. This control law is also defined as a linear system over the Min-Plus algebra. It is a causal state feedback, involving delays. The method is illustrated on a system arising from production processes." } @INPROCEEDINGS{Amat0505:Analog, AUTHOR="Alexandre {Graell i Amat} and Sergio Benedetto and Guido Montorsi and Daniele Vogrig and Andrea Neviani and Andrea Gerosa", TITLE="An Analog Turbo Decoder for the Rate-1/3, 40 bit, {UMTS} Turbo Code", BOOKTITLE="ICC 2005 Communication Theory", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="In this paper, we discuss the design and testing results of an analog $0.35~\mu m$ CMOS Turbo decoder for the rate-1/3, 40 bit, UMTS Turbo Code. The prototype was successfully tested at nominal conditions (2 Mbps), with an overall power consumption of 10.3 mW at 3.3 V. The tested BER curve shows a limited performance loss (about 0.5 dB) with respect to that of the digital implementation. We also discuss a discrete-time model of the analog decoder which allows to run BER simulations including device mismatch in a very short time. Circuit-level simulations demonstrate the validity of our model. According to the discrete-time simulation, a significant contribution to the performance loss is due to device mismatch." } @INPROCEEDINGS{Amat0509:Analysis, AUTHOR="Alexandre {Graell i Amat} and Guido Montorsi and Vatta Francesca", TITLE="Analysis and Design of {Rate-Compatible} Serial Concatenated Convolutional Codes", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="We provide a performance analysis of a new class of serial concatenated convolutional codes (SCCC) where the inner encoder can be punctured beyond the unitary rate. The puncturing of the inner encoder is not limited to inner coded bits, but extended to systematic bits. We derive analytical upper bounds to the error probability of this particular code structure and address suitable design guidelines for the inner puncturing patterns. We show that the percentile of systematic and parity bits to be deleted strongly depends on the SNR region of interest. Furthermore, we show that puncturing of inner systematic bits should be interleaver dependent. Based on these considerations, we derive design guidelines to obtain well-performing rate-compatible SCCCs families. Throughout the paper, the performance of the proposed codes are compared with analytical bounds, and with the performance of PCCC and SCCC proposed in literature." } @INPROCEEDINGS{Amee0505:Multiplier, AUTHOR="Salah Ameer and Behnam Shahrrava", TITLE="A Multiplier-free {NLMS} algorithm for Adaptive {IIR} Filtering", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Traditionally adaptive FIR filters are preferred for their stability and unimodality. However, IIR filters can perform better with less computation. Multiplier-free implementations (and finite precision in general) can have drastic effects on the performance of both types especially with noisy environment. In this work, inputs rather than the coefficients are rounded to the next power of two. Equation error and output error (assuming independent outputs) formulation can be implemented. Using geometric series expansion, a multiplier-free version of the normalized least-mean-squares (NLMS) algorithm is proposed for adaptive IIR filtering. A different approach in deriving the NLMS is also presented. It is worth noting that performing quantization on any quantity other than the data requires an extra one on a different quantity. Extensive simulations in system identification are shown indicating the usefulness of the algorithm even for long durations (poles near the unit circle) and non-exact modeling. Due to this severe quantization, increasing the order beyond a certain limit has no effect on the learning curve. The severe quantization also imposes some minimum noise floor even with infinite signal to noise ratio. An interesting observation is that exact- and under-modeled cases are of marginal difference when some of the poles are very close to the unit circle. This observation is valid to some extent for the three modeling cases when there is measurement noise. Slight degradation (<1dB) can be sacrificed to reduce computations. This degradation becomes unnoticeable for the over-modeled case. All operations were performed in 16-bit finite precision format. No improvements were noticed for higher precision in a similar fashion to FIR adaptive filters. However, a more elaborative work is needed to find the optimum precision." } @INPROCEEDINGS{Amin0506:Improving, AUTHOR="Mina Amin and Kin-Hon Ho and George Pavlou and Michael Howarth", TITLE="Improving Survivability Through Traffic Engineering in {MPLS} Networks", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="The volume of mission-critical and higher priority Internet applications is increasing as the Internet continues to evolve. Customers require Quality of Service (QoS) guarantees with not only guaranteed bandwidth and delay but also with high availability. In this paper, we formulate the off-line traffic engineering survivability problem. Our objective is, for each predicted traffic flow to find a primary path with improved availability and minimum failure impact while satisfying bandwidth constraints and also minimising network resource consumption. We devise a heuristic algorithm with four different cost functions that take link availability into account. We show through simulations that our approach enhances the availability of primary paths, reduces the effects of failure and also reduces the total resource consumption for both primary and backup paths." } @INPROCEEDINGS{Amin0506:Maximizing, AUTHOR="Alaa Amin and Reda Ammar and Sanguthevar Rajasekaran", TITLE="Maximizing Reliability while Scheduling Real-time Task-graphs on a Cluster of Computers", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="Real-time systems are being extensively used in critical-mission applications such as air-traffic control, medicine, telecommunications, e-commerce, etc. Usually, real-time applications need deadlines assurance, require high computational processing power and require long durations of reliable services plus timeliness of operation. Improper task assignment and scheduling of real-time applications on a cluster may lead to missing required deadlines and offset the gain of using the system and software parallelism. Most existing scheduling algorithms do not consider the impact of other factors such as system reliability, processing power fragmentation, inter-task communication and degree of parallelism on performance. In this paper we introduce a new scheduling algorithm, which is based on using an objective function to guide the search for a near optimal solution. This objective function includes different criteria such as real-time deadlines, reliability, and quantitative measures of the communication, degree of parallelism and processing power fragmentation. The presence of different criteria may affect the overall acceptance rate of the applications. We also investigate the effect of reliability on the overall acceptance rate." } @INPROCEEDINGS{Amir0501:Transmission, AUTHOR="Pouyan Amirshahi and Mohsen Kavehrad", TITLE="Transmission Channel Model and Capacity of Overhead Multi-conductor {Medium-Voltage} Power-lines for Broadband Communications", BOOKTITLE="IEEE Consumer Communications and Networking Conference", ADDRESS="Las Vegas, Nevada", DAYS=3, MONTH=jan, YEAR=2005, ABSTRACT="A channel model suitable for multi-wire overhead medium-voltage lines is proposed. The model, incorporating ground admittance, is more appropriate for broadband communications. This model is then employed in order to evaluate the multipath channel impulse response and the associated transmission capacity limit in actual overhead medium-voltage power distribution networks for broadband power-line communications applications." } @INPROCEEDINGS{Amir0506:1, AUTHOR="Yair Amir and Claudiu Danilov and Stuart Goose and David Hedqvist and Andreas Terzis", TITLE="{1-800-OVERLAYS:} Using Overlay Networks to Improve {VoIP} Quality", BOOKTITLE="NOSSDAV 2005", ADDRESS="Skamania, Washington", DAYS=12, MONTH=jun, YEAR=2005, ABSTRACT="The cost savings and novel features associated with Voice over IP (VoIP) are driving its adoption by service providers. Such transition however can successfully happen only if the quality and reliability offered is comparable to the existing PSTN. Unfortunately, the Internet's best effort service model provides no inherent quality of service guarantees. Because low latency and jitter is the key requirement for supporting high quality interactive conversations, VoIP applications use UDP to transfer data, thereby subjecting themselves to performance degradations caused by packet loss and network failures. In this paper we describe two algorithms to improve the performance of such VoIP applications. These mechanisms are used for localized packet loss recovery and rapid rerouting in the event of network failures. The algorithms are deployed on the routers of an application-level overlay network and require no changes to the underlying infrastructure. Initial experimental results indicate that these two approaches can be composed to yield voice quality on par with the PSTN." } @INPROCEEDINGS{Amir0506:System, AUTHOR="Pouyan Amirshahi and Mohsen Kavehrad", TITLE="System Design Considerations for High data Rate Communications Over Multi-wire Overhead Powerlines", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="Broadband powerline communications over multi-wire overheard lines using Orthogonal Frequency Division Multiplexing (OFDM) is considered in this paper. From earlier investigations, it is known that this channel suffers with multipath fading and frequency selectivity. Nevertheless, the calculated channel capacity limit promises very high data rates over this channel, subject to simple fixes. Enhancement techniques, such as coding can help, e.g, an OFDM system, to achieve this limit as close as possible. The smart use of coding and power allocation in OFDM will be useful to get the desired performance at higher data rates. These theoretic facts are confirmed by means of computer simulations." } @INPROCEEDINGS{Amis0509:Predictive, AUTHOR="Karine Amis and Dominique Leroux", TITLE="Predictive Decision feedback equalization for Space Time Block codes with orthogonality in frequency domain", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="We generalize the space time code structure of Lindskog and Al Dahir and define new Space Time Block Codes per Block. Compared to Space Time Block Codes they are well adapted to selective frequency channels. We thus propose an efficient receiver consisting of first a space time code frequency domain detector followed by a predictive decision feedback equalizer with frequency domain feedforward filter and time domain feedback filter. Simulations show the efficiency of the whole structure." } @INPROCEEDINGS{Amma0503:Dual, AUTHOR="Max Ammann", TITLE="{Dual-Band} Monopole Antenna With {Stagger-Tuned} Arms For Broadbanding", BOOKTITLE="IEEE International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials", ADDRESS="Marina Mandarin Singapore", DAYS=7, MONTH=mar, YEAR=2005, ABSTRACT="The paper describes a dual-band miniaturized printed monopole for integration in modern wireless systems. The printed monopole is augmented with two arms, resonant at slightly different frequencies, providing a broadened response for the upper band. The achieved bandwidth for the high band is 36\%. These antennas are proposed for the emerging dual-mode multi-band WLAN transceivers, which operate over a wide range of bands as dictated by national authorities. Measured and simulated data including return loss, antenna gain and radiation patterns are presented. The numerical method employed was the finite integration technique." } @INPROCEEDINGS{Amma0509:Adaptive, AUTHOR="Mohamed Lassaad Ammari and Francois Gagnon and Jean Belzile", TITLE="Adaptive {M-QAM} scheme and unbiased {MMSE-DFE} receiver", BOOKTITLE="VTC'F05 Transmission Technology", DAYS=26, MONTH=sep, YEAR=2005, ABSTRACT="An adaptive M-QAM scheme for a MMSE-DFE equalized system over a selective channel is proposed and the impact of channel variations on the AQAM-DFE performances is investigated. It is well known that the single parameter that characterizes an unbiased MMSE-DFE equalizer performances, in a given channel, is the signal-to-noise ratio (SNR) at its output. The MMSE-DFE output SNR value can be easily evaluated using MSE at the equalizer output. In order to select the appropriate modulation mode, the receiver estimates the MSE at the equalizer output. The estimated MSE is then sent back to the transmitter which adjusts the modulation level. The proposed switching parameter (MSE) does not require a high numerical computation. The influence of channel variations on the AQAM-DFE performances was also investigated. For this purpose, we have considered a channel model with two paths and a fade rate of 100 dB/s. For a channel SNR of 20 dB, numerical results show that the SNR at the MMSE-DFE equalizer variation from one frame to another is less that 0.03 dB. This deviation has a negligible impact on AQAM-DFE system performances. Simulation results show that the MSE is accurately estimated and represents a viable switching metric. It is also shown that switching between different modulation modes does not affect the equalizer coefficients adaptation." } @INPROCEEDINGS{Amma0510:Trade, AUTHOR="Habib M. Ammari and Sajal Das", TITLE="Trade-off between Energy Savings and {Source-to-Sink} Delay in Data Dissemination for Wireless Sensor Networks", BOOKTITLE="Eighth ACM/IEEE(*) International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems", DAYS=10, MONTH=oct, YEAR=2005, ABSTRACT="Wireless sensor networks (WSNs) consist of large numbers of unattended sensors with limited storage, energy (battery power) and computational and communication capabilities. Because battery power is the most crucial resource for sensor nodes and delay time is a critical metric for certain WSN applications which require fast response time, data dissemination between source sensors (data generating points) and sinks (data gathering points), which is an essential activity in WSNs, should be done in an energy efficient and timely manner. In this paper, we characterize the trade-off between energy savings and source-to-sink delay in order to extend the operation of individual sensors and hence increase the lifetime of the WSN, and enable sinks to receive sensed data in a timely fashion and make appropriate decisions quickly. To this end, the proposed data dissemination protocol decomposes the transmission range of a source sensor into a certain number of concentric circular bands (CBBs) based on a minimal distance between any pair of consecutive forwarding sensors. Then, it provides a classification of these CBBs based on their exterior radii which will help a source sensor express its degree of interest (DoI) in minimizing two metrics which are energy consumption and source-to-sink delay. Specifically, the protocol introduces the concepts of proxy forwarders, which are selected from a particular CBB based on the DoI in the abovementioned metrics which is specified by a source sensor, in order to build data dissemination paths followed by collected data packets towards a sink. We prove that the use of sensors nodes, which lie on or closely to the direct, shortest path between source and sink, as proxy forwarders, helps simultaneously minimize energy consumption and source-to-sink delay. Also, we compute theoretical lower bounds on these two metrics. Our simulation results are found to be consistent with our theoretical results, and show that the second CBB minimizes energy consumption, the last CBB minimizes source-to-sink delay, and the middle CBBs trade-off energy consumption with source to sink delay in disseminating collected data from source sensors to a sink." } @INPROCEEDINGS{Amma0511:Data, AUTHOR="Habib M. Ammari and Sajal Das", TITLE="Data Dissemination to Mobile Sinks in Wireless Sensor Networks: An Information Theoretic Approach", BOOKTITLE="2nd IEEE International Conference on Mobile Ad-Hoc and Sensor Systems", DAYS=7, MONTH=nov, YEAR=2005, ABSTRACT="Uncertainty is an inherent characteristic of wireless sensor networks (WSNs) due to uncertainty in wireless communication links, limited resources (e.g., energy, storage, CPU, bandwidth), mobility and topology, to name a few. Thus, resource-efficient data dissemination between sensor nodes (or data generators) and a sink (or data collector) becomes a challenging task, particularly if the sink is moving in a wireless sensor field. This paper proposes an energy-aware protocol, called Weighted Entropy DAta diSsemination (WEDAS) for disseminating data to a mobile sink in WSNs using an information theoretic approach. The proposed protocol attempts to quantify the uncertainty of position of a mobile sink and the remaining energy uncertainty of static sensor nodes in order to select the most appropriate ones that will act as data disseminators between static sources and mobile sink. The WEDAS protocol favors sensor nodes whose weighted entropy with respect to their location and remaining energy is the minimum to participate in building dissemination paths between sources and a mobile sink. Specifically, the concepts of relative mobility zone of a sink, which includes its most probable future positions, and coordinator node set, which restricts the search space of candidate data disseminators, are introduced to conduct the selection process. The analytic results show that the selection of sensors with minimum weighted entropy as data disseminators depends on not only their remaining energy but also their relative positions with respect to the mobile sink, which meets our goals of extending the lifetime of WSNs by minimizing and balancing energy utilization of sensor nodes." } @INPROCEEDINGS{Amme0503:Low, AUTHOR="Josephine Ammer and Jan Rabaey", TITLE="Low Power Synchronization for Wireless Sensor Network Modems", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="A simplification of synchronization requirements is necessary to meet the low power goals of wireless sensor networks (WSNs). Simply scaling existing synchronization systems to WSN data rates consumes more power than the entire allotted node budget. In this work, simplification of synchronization requirements was achieved through system level design of modulation scheme, data rate, packet length, and clock accuracy. Analog and digital implementations of the resulting synchronization functions are explored. A digital implementation was chosen because it requires a smaller header length and therefore reduces system energy consumption. The chosen scheme achieves better than 1e-4 BER at 13dB SNR, an implementation loss of 1.6dB over the ideal detection case, while consuming under 300uW." } @INPROCEEDINGS{Amor0507:Introducing, AUTHOR="Michele Amoretti", TITLE="Introducing Secure Peergroups in {SP2A}", BOOKTITLE="Hot Topics in Peer-to-Peer Systems", ADDRESS="San Diego, CA, USA", DAYS=21, MONTH=jul, YEAR=2005, ABSTRACT="Service-oriented Grids are aiming at new applications beyond traditional resource-oriented scientific computing. We argue that Community Support is emerging as the real killer application. Service-oriented systems provide a flexible solution for work groups which belongs to University Campuses, Research Labs, Enterprises, Finance environments. We are building the Service-oriented P2P Architecture (SP2A), which is the result of the positive convergence between Grid and Peer-to-Peer computing. P2P design allows to overcome the limitations of available mechanisms for publishing and discovering Grid Services, which are essentially based on centralized directories, thus raising robustness, scalability and performance concerns. SP2A is constituted by distinct communities of peers organized for specific purposes. In this paper we illustrate the group security policies of SP$^2$A, which define the mechanisms for peer authentication, peergroup admission control, authorization and transport security. Prototype implementation details are also exposed." } @INPROCEEDINGS{AN0511:Multipath, AUTHOR="Hui-Yao An and Lu Xicheng and Wei Peng", TITLE="A Novel Multipath Routing Integrated with {FEC} in {MANET}", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="Multipath routing is a parallel communication method which distributes traffic into multiple paths. It has the drawback with increasing the ratio of packet disorder and packet loss rate. In order to improve the data transmission reliability of MANET, a routing scheme called IFECMRP (Integrated with FEC Multipath Routing Protocol) which integrates the technique of packet fragmenting and FEC (Forward Error Correction) encoding into multipath routing is proposed. The scheme works as follow: adding a certain redundancy into the original packets; fragmenting the resulting packets into exclusive blocks of the same size; encoding with the FEC technique, and then sending them to the destination node. When the receiving end receives a certain amount enough of information blocks, the original information will be recovered even under partial loss. The performance of the scheme is evaluated using OPNET modeler, experimental results show that the method can decrease the average transmission delay about 20\%, improve the transmission reliability about 30\%." } @INPROCEEDINGS{Anag0507:Context, AUTHOR="Christos Anagnostopoulos and Stathes Hadjiefthymiades", TITLE="Context Management in Pervasive Computing Environments", BOOKTITLE="IEEE International Conference on Pervasive Services (ICPS) 2005", DAYS=11, MONTH=jul, YEAR=2005, ABSTRACT="Pervasive computing is a broad and compelling research issue in Computer Science and Telecommunications Engineering. Its primary objective is the creation of an environment saturated with seamlessly integrated devices with computing and communication capabilities. It seeks to provide proactive and self-tuning environments and devices to seamlessly augment a person's knowledge and decision-making ability, while requiring as little direct user interaction as possible. The realization of this vision requires that distributed context manipulation is conducted in an effective and efficient manner. In these environments, devices and associated software of diverse software and hardware providers will pervade everyday life. That poses a very important interoperability issue among heterogeneous objects, as it cannot be assumed that the various hardware and software components share common communication and data schemes. We proposed a UML Profile for modeling such a pervasive computing environment including context modeling and distributed knowledge manipulation." } @INPROCEEDINGS{Anag0507:Enabling, AUTHOR="Theodoros Anagnostopoulos and Christos Anagnostopoulos and Stathes Hadjiefthymiades", TITLE="Enabling Attack Behavior Prediction in Ubiquitous Environments", BOOKTITLE="IEEE International Conference on Pervasive Services (ICPS) 2005", DAYS=11, MONTH=jul, YEAR=2005, ABSTRACT="The Pervasive Computing paradigm has introduced issues such as conceptual semantic descriptions and ambient management information resources. The probabilistic theory on the other hand provides uncertain knowledge representation schemes that are semantically deficient regarding their information. However, security models related to attacks exploits both semantic and probabilistic modeling. Issues such as attack prediction and classification of attackers intentions are assumed to be of high importance in IDS environments. In this paper we propose a novel Breadth and Depth Bayesian classifier and an inference probabilistic algorithm, over well defined conceptual information that resides in hybrid IDS by means of ontology." } @INPROCEEDINGS{Anan0504:New, AUTHOR="Bharath Ananthasubramaniam and Raghuraman Mudumbai and Upamanyu Madhow", TITLE="New Communication Paradigms for Very {Large-Scale} Sensor Networks", BOOKTITLE="The Fourth International Conference on Information Processing in Sensor Networks", ADDRESS="Los Angeles, CA", DAYS=25, MONTH=apr, YEAR=2005, ABSTRACT="In this poster, we will present work in progress on two novel approaches for efficient, scalable communication in truly large scale sensor networks. This work is a follow-up on our papers in IPSN 2004 .Our focus is on applications in which networks of tens of thousands of sensor nodes are required, such as policing activity along a border, monitoring the presence of biological or chemical agents over large urban areas, or exploration of the surface of a planet. Not only is it difficult to scale standard multihop wireless networking protocols to such large networks, but in many such settings, one long hop is required from the cluster of sensor nodes to a remote collector node even if multihop networking among the sensor nodes is feasible. Another key difficulty in large scale networks is localization: such networks would often be randomly deployed, e.g., dropped from an aircraft or spacecraft, so that there is no a priori mapping between sensor node ID and location. Furthermore, geolocation may be unavailable due to either cost (of integrating GPS receivers into sensor nodes) or physical considerations (occlusion of GPS signals in many scenarios, and unavailability in settings such as interplanetary exploration or monitoring of wooded areas). With the preceding context in mind, we introduce two novel concepts." } @INPROCEEDINGS{Anan0505:Characterization, AUTHOR="Pranavi Anand", TITLE="Characterization of {ANEXT} in {10GBASE-T} Systems", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Characterization of ANEXT in 10GBASE-T systems Pranavi Anand Stephen Bates M.Sc. Student Assistant Professor Dept. of Electrical and Computer Eng. Dept. of Electrical and Computer Eng. University of Alberta University of Alberta e-mail: pranavi(at)ece.ualberta.ca e-mail: stephen.bates(at)ece.ualberta.ca ABSTRACT The latest proposed Ethernet standard is 10GBASE-T or 10 Gigabit Ethernet, which achieves a data rate of 10 Gigabits per second (Gbps). This currently meets the everincreasing demand for data rate and bandwidth. The 10GBASE-T data signals will travel over unshielded twisted pair (UTP) copper cables. The range of frequencies involved will be from 250MHz to 500MHz. The high frequencies approaching the Gigahertz (GHz) range involved in the operation of 10GBASE-T standard give rise to a new type of crosstalk in data cables, which was not an issue in earlier lower data-rate Ethernet Standards. This has been named Alien Near-End Crosstalk (ANEXT). ANEXT has been predicted to be one of the major impairments for 10GBASE-T systems. Therefore, it is necessary to accurately measure ANEXT and model its behaviour to develop techniques to eliminate this problem and attain reliable transmission of data. The modeling of ANEXT is difficult due to the unavailability of field measurement instruments that can be used in real-world installations. An innovative technique to measure Alien Near-End Crosstalk in 10Gigabit Ethernet systems is proposed in this paper. A novel model for ANEXT is developed on the basis of measurement data obtained from experiments performed in a laboratory environment. Digital signal processing techniques are used to design the ANEXT model. The model represents the characteristics in the form of a low pass filter and fits with the measurement data. The experiments were conducted using a wireline testbed on Category(CAT) 5E and CAT6 UTP cables. ANEXT was measured on different sections of cable by laying two cables together. The effect of bundling was observed by coiling the cables together. Experiments were also performed to measure ANEXT at the connectors. A separate set up in which the UTP cables were connected to Ethernet jacks in 24-port patch panels was employed. The measurement results of the different experiments were used to design the proposed model for ANEXT. Subject Areas 1) Communications and Wireless Systems, 2) Digital Signal Processing, 3) Instrumentation \& Measurement CONTACT PERSON Dr. Stephen Bates Assistant Professor 9107-116 ST , 2nd Floor ECERF Edmonton, Alberta Canada T6G 2V4 Tel.: (780) 492-2691 Fax : (780) 492-1811 e-mail: stephen.bates(at)ece.ualberta.ca" } @INPROCEEDINGS{Anan0506:Management, AUTHOR="Rema Ananthanarayanan and Ajay Gupta and Mukesh Mohania", TITLE="Management of Conflicting Obligations in {Self-Protecting} Policy Based Systems", BOOKTITLE="IEEE International Conference on Autonomic Computing", ADDRESS="Seattle, Washington", DAYS=13, MONTH=jun, YEAR=2005, ABSTRACT="Policy-based management of business systems is increasingly becoming the norm for autonomic computing since these systems can adapt to the changing needs and increasing complexity of the underlying organizations or enterprises. One of the vital characteristics of these systems is self-protection, ie., the ability to secure information and resources, by anticipating, detecting, identifying and protecting against any form of unauthorised access and permitting all authorised accesses based on the users' role and pre-established policies. In this paper, we focus on one aspect of self-protecting autonomous systems, that is, how to automatically enforce privacy policies related to data handling, for compliance and auditing purposes. The automatic management of privacy sensitive information based on enterprise policies that are driven by a combination of user preferences, internal objectives and external regulations is a key aspect to any enterprise to prevent misuse of this information. These policies extend beyond simple authorization rules, and also mandate obligations to be enforced under certain conditions. One issue in the automatic enforcement of obligations is the presence of conflicts among different obligations which mandate different actions on the same resource, based on different conditions in which the resource is accessed. In this paper we propose algorithms for detecting and resolving conflicts among obligations in both static and runtime environments. We then briefly describe our prototype obligation management system with the conflict resolution module that achieves the automated enforcement of obligations for data-handling based on privacy policies." } @INPROCEEDINGS{Anan0509:Detection, AUTHOR="Bharath Ananthasubramaniam and Upamanyu Madhow", TITLE="Detection and Localization of Events in Imaging Sensor Nets", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="We consider an Imaging Sensor Net, in which a stationary collector node employs imaging techniques for localization and data collection from sensor nodes without geolocation or inter-networking capabilities. Sensors that are near enough to an event of interest become active. We consider a dense sensor field, in which multiple sensors are activated by the same event. The collector scans the sensor field with a directional antenna. Active sensors which fall in the beam electronically reflect the collector's beacon, thus creating a radar-like geometry. The collector processes the observations obtained in multiple beams to obtain maximum likelihood estimates of the locations of events of interest." } @INPROCEEDINGS{Anan0509:Distributed, AUTHOR="Madhukar Anand and Sebastian Fischmeister and Jesung Kim and Insup Lee", TITLE="Distributed Code Generation from Hybrid Systems Models for Time-delayed Multirate Systems", BOOKTITLE="EMSOFT 2005", ADDRESS="Jersey City Hyatt, Jersey City NJ", DAYS=18, MONTH=sep, YEAR=2005, ABSTRACT="Hybrid systems have emerged as an appropriate formalism to model embedded systems as they capture the theme of discrete control with continuous dynamics. Code generation from hybrid systems models is a technique to produce embedded software with formal guarantees. The hybrid systems model is set in continuous time with concurrent execution of different agents. However, most implementation platforms have agents evolving at different rates and interacting with each other in the presence of delays and therefore, realizing the semantics of the original model is challenging. Our earlier work introduced a framework for code generation from hybrid systems models. In this paper, we address the problem of providing a faithful implementation for a large class of systems. The notion of a faithful implementation is difficult to define in systems with communication delays and multiple rates of evolution with dependent dynamics. Relative faithful implementation is therefore an appropriate metric for translation of the model. Even under this relaxed criteria, the implementation should be free of faulty or missed transitions. We introduce Dynamic Instrumentation at runtime as an approach to prevent faulty transitions and design a co-operative compensation technique to implement it. We also identify sufficient conditions to ensure no missed transitions in the code. A time deterministic implementation is deemed sufficient to ensure these properties and one such implementation is presented here." } @INPROCEEDINGS{Anan0509:Downlink, AUTHOR="Santhanakrishnan Anand and A. Chockalingam", TITLE="Downlink Power Allocation with Pricing in {CDMA}", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", MONTH=sep, YEAR=2005, ABSTRACT="In this paper, we present an approach for power allocation to maximize the effective system throughput with pricing on the downlink in a CDMA system. We present a pricing policy and obtain the optimum powers for the users to maximize the effective system throughput incorporting this pricing policy. We also study the asymptotic behavior of the system(i.e., when the number of users and the available bandwidth are large). We show that in such a system, all users obtain equal SIR at the optimum point irrespective of their locations and processing gains." } @INPROCEEDINGS{Anan0511:Designing, AUTHOR="Noppin Anantrasirichai", TITLE="Designing Rectangular Slot Loop Antenna for {WLAN} Application", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="This paper presents the design of rectangular microstrip slot loop antenna that competently achieves dual frequency operation by using a microstrip feed line. This antenna is designed at the resonance frequency 2.4 GHz and 5.2 GHz thereby covering the required frequency-bandwidth of 2.4-2.4836 GHz and 5.15-5.35 GHz, which are widely used in Wireless LAN (WLAN). The characteristics of antennas are proposed and analyzed for instance input impedance, S11 parameter and far field patterns. The antenna is analyzed by Finite Difference Time Domain (FDTD) method which can predict and analysis of the electromagnetic responses of complex problems." } @INPROCEEDINGS{Anan0511:Eeducating, AUTHOR="Muriyankulangara Ananthakrishnan", TITLE="Educating Nomadic Children: An Experiment with the Convergence of Technologies", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="EDUCATING NOMADIC CHILDREN: AN EXPERIMENT WITH THE CONVERGENCE OF TECHNOLOGIES The wandering nature of the nomads in a vast country like India has had a toll on their children, who are denied even a semblance of formal or regular education. This results invariably in the children continuing with the traditional nomadic culture. Maharashtra, a state in western India shares borders with a number of neighbouring states. The nomadic tribes in this state, therefore, invariably wander amongst the neighbouring states. This paper is a report on an exciting experiment with convergence of tradition and ICT. The author and his team have studied the tribes in detail and have evolved a methodology that involves the use of all available technologies, based on relevance, availability, portability, repeatability and flexibility. The initial experiments carried out with three tribes in Maharashtra, have created the much needed motivation in the children and mothers and given the assurance that the efforts will bear fruit." } @INPROCEEDINGS{Anan0511:Optimized, AUTHOR="Avishek Anand and Kiran Rk", TITLE="Optimized and Adaptive Link State Routing Strategy", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="The dominant link state protocols like OSPF despite their advantages require the flooding of new information across the entire routing area after changes in any link state. With the growth of the network diameter or the frequency of link-state changes increases, the overhead in terms of bandwidth and processing cost, of flooding becomes prohibitive. Furthermore, such flooding over a large area will cause unnecessary overhead on the links, potentially creating many transient routing loops that can last for a long time. This limits the scalability of the routing protocols to large routing areas. To overcome such problems, we present in this paper an Optimized and Adaptive Link-State Protocol (OALP), a modification to the existing link-state routing protocol that does not require the state of each link to be flooded to the entire internetwork all the time, or to entire areas if we monitor the activity status of the nodes in the internetwork. Thus minimizing the amount of information distributed by link-state routing protocols. There are primarily two modes in which we devise the network to operate depending the activity levels of the incumbent nodes. Depending on the activity levels an optimized flooding procedure is provided which would greatly reduce the number of advertisements flowing through the network." } @INPROCEEDINGS{Anas0506:TPA, AUTHOR="Giuseppe Anastasi and Emilio Ancillotti and Marco Conti and Andrea Passarella", TITLE="{TPA:} A Transport Protocol for Ad hoc Networks", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="The TCP protocol exhibits poor performance in Mobile Ad Hoc Networks (MANETs). The ultimate reason for this is that MANETs behave in a significantly different way from traditional wired networks, like the Internet, for which the TCP protocol was originally designed. In particular, congestion phenomena in MANETs are very different than in traditional wired networks. In addition, route failures and route changes may be frequent events. In this paper we propose a novel transport protocol named TPA for MANETs. TPA is not a modified version of TCP, but it is specifically tailored to the characteristics of the MANET environment. It is based on a completely new congestion control mechanism, and is designed in such a way to reduce as much as possible the number of useless re-transmissions and, hence, power consumption. Furthermore, it is able to manage efficiently route changes and route failures. We evaluated the TPA protocol in a static scenario where TCP exhibits good performance. Simulation results show that, even in such a scenario, TPA performs significantly better than TCP." } @INPROCEEDINGS{Anas0507:Power, AUTHOR="Giuseppe Anastasi and Marco Conti and Enrico Gregori and Andrea Passarella and Luciana Pelusi", TITLE="A {Power-Aware} Multimedia Streaming Protocol for Mobile Users", BOOKTITLE="IEEE International Conference on Pervasive Services (ICPS) 2005", DAYS=11, MONTH=jul, YEAR=2005, ABSTRACT="Smart environments are becoming popular and even more users are approaching their services. However, since pervasive devices (PDAs, mobile phones, laptops, etc.) have limited resources when compared to desktop computers, a very critic factor in the development of pervasive services is the efficiency of resources management, especially (since most of these devices use batteries) energy efficiency. In this paper we focus on the diffusion of multimedia streaming services in smart environments. Specifically, we investigate scenarios where mobile users receive audio files from streaming servers located in the Internet through a Wi-Fi access. We have designed an adaptive scheduling algorithm that manages streaming of frames while providing periodic interruptions of transmission in order to allow setting the network interface card at the mobile terminal to a low-power consuming state i.e., a sleep mode. We have implemented a software prototype in order to test the effectiveness of our solution and conducted an extensive experimentation under different conditions of data rate and competing background traffic. Experimental results show that our solution makes possible energy saving ranging from 79.41\% to 90\% of the total consumption due to the network interface in absence of any power saving policy. Moreover, experimented frame losses never overtake 5\% of the total file length and the initial delay to the playback is always less than 2 s, thus resulting in a good QoS returned to the user." } @INPROCEEDINGS{Anba0511:Data, AUTHOR=" Anbananthen", TITLE="Data Mining using Artificial Neural Network Tree", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="Proper diagnosis, classification and prediction of diabetes are essential due to the increasing prevalence of the disease and the increasing cost to control it. Appropriate discovery of knowledge from historical data for this disease would be a valuable tool for clinical researchers. The main purpose of data mining is to gain insight of the data, and extract knowledge (inter-relational patterns) from the data. Applying data mining techniques in diabetic data can facilitate systematic analysis. Artificial Neural network (ANN) has already been applied in a variety of domains with remarkable success. However, it has not has been well utilized in data mining because of the black box nature. In this paper we present a method of using ANN in data mining and overcoming the black box nature using Decision Tree (DT)." } @INPROCEEDINGS{Ande0505:Development, AUTHOR="Thorsten Anders", TITLE="Development of a generic {IT} service catalog as pre-arrangement for Service Level Agreements", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Generally speaking, information usually just gains significance only when it is being processed in the context of own experience and being linked to other information. This article describes the development of a generic model for an IT service catalog which could for instance be adapted and utilized by an IT provider in the field of a service management project. The design is component based on a new hierarchical approach. The specification of the IT services by this approach allows instant classification of who should handle the activity and how it should handled. The atomic structure affords the representation of functional dependence. Moreover the hierarchical design makes the relationships between different components more clear. Additionally there is a discussion of the terms IT service and IT business process, a dual matrix for both quality of service (QoS) parameters will be introduced." } @INPROCEEDINGS{Ande0506:Differential, AUTHOR="Adam Anderson and Michael Jensen and James Zeidler", TITLE="Differential {Space-Time} Coding With Offset Quadrature {Phase-Shift} Keying", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="Differential space-time coding (DSTC) has been well established as a precoding technique that allows maximum likelihood detection of the received symbols without requiring knowledge of channel state information. This type of detection is useful for highly time-varying channels where the resulting cost of channel estimation is high. However, to date, this approach has not been developed for the commonly-used offset modulations that offer improved spectral performance in the presence of nonlinear transmit power amplifiers. This paper illustrates modifications to the DSTC detection strategy for offset quadrature phase shift keying. Furthermore, it is shown that while traditional DSTC achieves a reduced transmission rate, the combination with offset modulation allows full rate transmission if desired." } @INPROCEEDINGS{Ande0509:BCJR, AUTHOR="John Anderson and Norbert Goertz and Tomas Eriksson", TITLE="On the {BCJR} Algorithm for {Rate-Distortion} Source Coding", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="The BCJR algorithm is an important method of channel decoding. We extend it here to rate-distortion encoding. Beginning from source coding principles, the argument makes no use of channel coding or soft output ideas. Codeword ensembles with equiprobable reproducer letters play an important role. The BCJR method is demonstrated by tests of a tailbiting variant with the Laplace source. The outcome improves upon Viterbi algorithm performance at short and medium word lengths." } @INPROCEEDINGS{Ande0511:Shaping, AUTHOR="Jens Andersson and Christian Nyberg", TITLE="Shaping in multi service architectures", BOOKTITLE="The Third Swedish National Computer Networking Workshop 2005", DAYS=23, MONTH=nov, YEAR=2005, ABSTRACT="In a web service architecture with a time constraint, the burstiness of arriving requests is an important issue. The burstiness can be controlled and reduced with shaping algorithms. In this paper traditional shaping algorithms are compared and evaluated. Different methods are suitable for different situations. Some common shaping algorithms are described, and suitable areas of use are proposed. Network Calculus is used as a tool for comparisons." } @INPROCEEDINGS{Ande0511:Web, AUTHOR="Mikael Andersson and Anders Bengtsson and Martin {Höst} and Christian Nyberg", TITLE="Web Server Traffic in Crisis Conditions", BOOKTITLE="The Third Swedish National Computer Networking Workshop 2005", DAYS=23, MONTH=nov, YEAR=2005, ABSTRACT="During recent years we have seen several large-scale crises. The 9/11 terror attacks, tsunamis, storms, floods and bombings have all been unpredictable and caused a great deal of damage. One common factor in these crises has been the need for information and one important source of information is usually web sites. In this work three new sets of web server access logs are presented and analyzed, one of which represent the traffic to the major news site, Aftonbladet, in Sweden after the bombings in London, 7th of July 2005. The differences in document popularity between the crisis logs and the other logs are investigated." } @INPROCEEDINGS{Andr0503:Bounds, AUTHOR="Matthew Andrews and Lisa Zhang", TITLE="Bounds on Fiber Minimization in Optical Networks with Fixed Fiber Capacity", BOOKTITLE="IEEE INFOCOM 2005", ADDRESS="Miami", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="We consider the problem of minimizing the amount of deployed fiber in optical networks where each fiber carries a fixed number of wavelengths. We are given a network of general topology and a set of demands specified by a source node and a destination. For each demand we wish to choose a route and a wavelength. The number of fibers required on a link equals the maximum, over all wavelengths, of the number of demands that are assigned that wavelength and are routed through the link. We wish to minimize the total amount of fiber deployed in order to carry all the demands. Past work either assumed an unlimited number of wavelengths or else was restricted to specific topologies such as lines, rings and trees. We show that for general topologies the problem is hard to approximate. In particular we show that for any $\ve>0$ there is no $O(\log^{1/4-\ve} N)$ approximation algorithm unless all problems in NP can be solved by randomized algorithms with expected running time $O(n^{polylog~n})$. On the positive side we describe methods to choose routes and randomly choose wavelengths in order to obtain a logarithmic approximation ratio. Lastly we present some heuristics for wavelength assignment that outperform random assignment and which are close to optimal on some example problems on a synthetic backbone network. Keywords: System design, Mathematical programming/optimization, Graph theory, Combinatorics" } @INPROCEEDINGS{Andr0503:Maximizing, AUTHOR="Matthew Andrews", TITLE="Maximizing profit in overloaded networks", BOOKTITLE="IEEE INFOCOM 2005", ADDRESS="Miami", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="We consider the problem of scheduling packets in overloaded networks. We wish to maximize the total profit of data that is served. We first consider a single server that has to schedule packets over time-varying channels. This model is motivated by scheduling data in wireless networks. Our objective is to maximize $\sum\_i \log R\_i(t)$ where $R\_i(t)$ is the total amount of data scheduled to user $i$ by time $t$. In contrast to most previous work we assume that the channel conditions are defined by an {\em adversary} rather than a stationary, stochastic process. We give lower bounds on how competitive an online algorithm can be and show that the bounds are nearly matched by a simple randomized algorithm. We also consider a situation in which packets with associated profits are injected into a network of servers. We wish to schedule the packets in the network and maximize the profit of data that reaches its destination. We show that if the servers are allowed to exchange control packets that inform each other of the congestion in the network then we can approximate the optimum profit arbitrarily closely. We also show that without these control packets this is not possible. Our results are motivated by recent work on primal-dual algorithms for flow control in networks. The key difference between our approach and this previous work is that we take into account the scheduling dynamics in the network. Keywords: System design, Stochastic processes/queueing theory." } @INPROCEEDINGS{Andr0503:Optimal, AUTHOR="Matthew Andrews and Lijun Qian and Alexander Stolyar", TITLE="Optimal Utility Based {Multi-User} Throughput Allocation subject to Throughput Constraints", BOOKTITLE="IEEE INFOCOM 2005", ADDRESS="Miami", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="We consider the problem of scheduling multiple users sharing a time-varying wireless channel. (As an example, this is a model of scheduling in 3G wireless technologies, such as CDMA2000 3G1xEV-DO downlink scheduling.) We introduce an algorithm which seeks to optimize a concave utility function $\sum\_i H\_i(R\_i)$ of the user throughputs $R\_i$, {\em subject to certain lower and upper throughput bounds: $R\_i^{min} \le R\_i \le R\_i^{max}$}. The algorithm, which we call the Gradient algorithm with Minimum/Maximum Rate constraints (GMR) uses a {\em token counter} mechanism, which modifies an algorithm solving the corresponding {\em unconstrained} problem, to produce the algorithm solving the problem with throughput constraints. Two important special cases of the utility functions are $\sum\_i \log R\_i$ and $\sum\_i R\_i$, corresponding to the common Proportional Fairness and Throughput Maximization objectives. We show asymptotic optimality of GMR in the sense that if, under an appropriate scaling, the throughput vector $R(t)$ converges to a fixed vector $R^*$ as time $t\to\infty$ then $R^*$ is a solution to the optimization problem described above. We also present simulation results showing the algorithm performance. Keywords: Stochastic processes/Queueing theory" } @INPROCEEDINGS{Andr0504:CLAMP, AUTHOR="Lachlan Andrew and Stephen Hanly and Rami Mukhtar", TITLE="{CLAMP:} Active queue management at wireless access points", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="This paper investigates the performance of CLAMP, a distributed algorithm to enhance the performance of TCP connections that terminate in a wireless access network. CLAMP works at a receiver to control a TCP sender by setting the TCP receiver's advertised window limit. CLAMP provides explicit control over wireless link utilisation and queueing delay at the access point buffer, and can drastically increase the throughput of so-called short TCP flows with negligible loss in long TCP flow throughput." } @INPROCEEDINGS{Andr0505:Component, AUTHOR="Robert Andrews and Behan Webster", TITLE="A Component Oriented Software Engineering Approach to a Deeply Embedded Firmware Control Platform.", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="structures called Objects. Traditional Objects tend to be difficult to implement within the constraints of deeply embedded control platforms. In this paper we discuss the application of a new methodology, Component Oriented Software Engineering to the implementation of an embedded control system. Objects are replaced by simpler entities called Components which are neither constructed or destructed within the embedded controller, but instead are created or re-incarnated. These Components are placed in application specific Kontainers to constrain and manage their interconnectivity, permitting construction by composition but without inheritance. Furthermore, the mapping of specific instances of a component to a specific location in a Kontainer can be modified at run time thereby allowing the use of a single firmware load running on a generic control platform for multiple device architectures. The paper also explores an extension to this work that will allow the control firmware to adapt top and accommodate aging components, an area significant importance in both telecommunications systems and medical devices." } @INPROCEEDINGS{Andr0505:Generating, AUTHOR="Maria Andreou and Vicky Papadopoulou and Paul Spirakis and Barbara Theodorides and Andreas Xeros", TITLE="Generating and Radiocoloring Families of Perfect Graphs", BOOKTITLE="4th International Workshop on Efficient and Experimental Algorithms", ADDRESS="Santorini Island, Greece", DAYS=10, MONTH=may, YEAR=2005, ABSTRACT="In this work we experimentally study the {\em min order Radiocoloring problem} (RCP) on {\em Chordal, Split} and {\em Permutation} graphs, which are three basic families of {\em perfect graphs}. This problem asks to find an assignment using the minimum number of colors to the vertices of a given graph $G$, so that each pair of vertices which are at distance at most two apart in $G$ have different colors. RCP is an NP-Complete problem on chordal and split graphs \cite{BK00}. There are known upper bounds for the number of colors needed by an optimal radiocoloring assignment and approximation algorithms for such graphs, \cite{BK00,S94}. In our study we design and implement radiocoloring heuristics for graphs of above families, which are based on the greedy heuristic. Also, for each one of above families, we investigate whether there exists graph instances requiring a number of colors in order to be radiocolored, close to the best known upper bound for the family. Towards this goal, we present a number generators that produce graphs of the above families that require either (i) a large number of colors (compared to the best upper bound), in order to be radiocolored, called ``extremal'' graphs or (ii) a small number of colors, called ``non-extremal''instances. The experimental evaluation showed that random generated graph instances are in the most of the cases ``non-extremal'' graphs. Also, that greedy like heuristics performs very well in the most of the cases, especially for ``non-extremal'' graphs." } @INPROCEEDINGS{Andr0505:GRASP, AUTHOR="Marcos Andrade and Simone Martins and Alexandre Plastino", TITLE="{GRASP} with {Path-Relinking} for the Maximum Diversity Problem", BOOKTITLE="4th International Workshop on Efficient and Experimental Algorithms", ADDRESS="Santorini Island, Greece", DAYS=10, MONTH=may, YEAR=2005, ABSTRACT="The Maximum Diversity Problem (MDP) consists in identifying, in a population, a subset of elements, characterized by a set of attributes, that present the most diverse characteristics between themselves. The identification of such solution is a NP-hard problem. This paper presents a GRASP heuristic associated with the path-relinking technique developed to obtain high-quality solutions for this problem in a feasible computational time. Experimental results illustrate the effectiveness of using the path-relinking method to improve results generated by pure GRASP." } @INPROCEEDINGS{Andr0505:Interference, AUTHOR="Guillaume Andrieux and Jean Francois Diouris and Yide Wang", TITLE="Interference Reduction in Time Duplex Systems by {Space-Time} Beamformers", BOOKTITLE="Vehicular Technology Conference Spring 2005 Transmission Technology", ADDRESS="Stockholm, Sweden", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="In cellular mobile radio systems, transmit beamformers can be used to reduce the Multiple Access Interference (MAI) in the downlink in order to increase the quality and the capacity of communication systems. However, for the most conventional beamforming methods, the Inter-Symbol Interference (ISI) is not taken into account, limiting the performances of these methods. The purpose of this paper is to propose a new method which uses frequency-selective beamformers to reduce jointly the MAI and the ISI. Uplink data obtained with an UMTS-TDD measurement campaign have been used to simulate the behaviour of the proposed method. Simulations show the efficiency of this method which improves the performances." } @INPROCEEDINGS{Andr0505:Reduced, AUTHOR="Robert Andrews and Behan Webster", TITLE=": Reduced Manufacturing Costs and Freedom in Vendor Selection", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="an analog signal value. These firmware models can be difficult to manage when the real world components vary significantly from unit to unit or from batch to batch, as is often the case for the Optical Components used in telecommunication and medical devices, resulting in added costs to preselect the components or deployment limitation to single vendor solutions. This paper describes a firmware object model that provides a run time configurable calibration data structure which manages the firmware complexity, hides the component to component variability from the control algorithms, and remains suitable for small memory limited embedded control processors. Using this Object Model, we have successfully demonstrated a single instance of control firmware, running on a common hardware platform, which manages a cascade of five complex optical devices from three vendors to form a span in an optical network." } @INPROCEEDINGS{Andr0509:Asymptotically, AUTHOR="Iryna Andriyanova and Jean-Pierre Tillich and Jean-Claude Carlach", TITLE="Asymptotically good codes with high iterative decoding performances", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="We investigate a new class of codes in this article which is some sense a hybrid between LDPC codes and turbo-codes. We show that when the parameters of this family are well chosen they have at the same time very good iterative decoding performances and a minimum distance which is typically linear in the length of the code." } @INPROCEEDINGS{Andr0509:Encoders, AUTHOR="Kenneth Andrews and Samuel {Dolinar, Jr.} and Jeremy Thorpe", TITLE="Encoders for {Block-Circulant} {LDPC} Codes", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="In this paper, we present two encoding methods for block-circulant LDPC codes. The first is an iterative encoding method based on the erasure decoding algorithm, and the computations required are well organized due to the block-circulant structure of the parity check matrix. The second method uses block-circulant generator matrices, and the encoders are very similar to those for recursive convolutional codes. Some encoders of the second type have been implemented in a small Field Programmable Gate Array (FPGA) and operate at 100 Msymbols/second." } @INPROCEEDINGS{Andr0509:Providing, AUTHOR="Alessandro Andreadis and Giuliano Benelli and Giovanni Luca Daino", TITLE="Providing {VHE} features to a multi-purpose secure service platform", BOOKTITLE="ISWCS 2005 Main Symposium", ADDRESS="Siena, Italy", DAYS=5, MONTH=sep, YEAR=2005, ABSTRACT="During the last years, 3G standardization activities leaded to new directions both in network and service provisioning architecture. As a result, new concepts of service portability have been defined (i.e., Virtual Home Environment - VHE) and new topics related to security issues are gaining a significant impact. Taking into account such an input, we moved to promote the development of a new generation of personalized services for citizens, students and bank customers, accessible anytime, anywhere and with any technology. In order to allow a wireless trusted secure access to information services, we propose here a service brokering platform. Based on Java and XML technology, the system implements user profiling techniques to tailor contents in a way that is independent of the specific device (fixed or mobile) used to get access. We believe that such a new approach will carry to a fruitful user-friendliness in service management, allowing the user to interact with services in an intuitive and personalized way." } @INPROCEEDINGS{Andr0511:Evaluation, AUTHOR="Lachlan Andrew and Irena Atov and David Kennedy and Bartek Wydrowski", TITLE="Evaluation of {FAST} {TCP} in {Low-Speed} {DOCSIS-based} Access Network", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="There is strong evidence that the efficiency of the Internet is limited by its existing TCP congestion control system. A replacement, FAST, has been shown to improve performance in high-speed networks. In order to achieve widespread acceptance and standardisation, it must also be tested in environments more typical of the existing Internet. This paper experimentally evaluates the performance of FAST over a typical access link, with bandwidths of around 0.5-3\,Mbps. Links both using the DOCSIS cable modem medium access control (MAC) protocol and simple low rate links were investigated. It is shown that the random delay introduced by MAC protocol of the cable modem does not appear to interfere significantly with FAST's ability to set the congestion window size to its target. However, the cable modem does appear to introduce consistent additional delays when the link is highly, but not fully, utilised. These unexplained delays mean that a larger congestion window is required, and must be taken into account when setting FAST's parameters, notably the target queue size, alpha." } @INPROCEEDINGS{Andr0511:Single, AUTHOR="Samraj Andrews", TITLE="Single Trial {VEP} source separation through Sandwich Spectral Power Ratio method", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="In single trial source separation problem of VEP signals, the selection of legitimate Principal Components (PCs) is an important phenomenon. The Spectral Power Ratio (SPR) method developed by us earlier for PCA has proven to be capable of selecting only the required PCs in a sophisticated manner. Our continuous enhancement has lead to the current development of the proposed method, Sandwich SPR (SSPR). The SSPR performs the reconstruction of source signal in an effective way better than the related SPR method. When this technique was applied on artificial Visual Evoked Potential (VEP) signals contaminated with background electroencephalogram (EEG), with a focus on extracting P3 parameters, it was found to be feasible shown by the resulting high values of the Signal to Noise ratio (SNR) as compared to the SPR and 2 tier SPR (SPR2) methods. Subsequently, we applied this method to study the P3 amplitude responses of a set of real EEG from Wadsworth BCI dataset obtained with target and non-target stimuli, and found that the P3 parameters extracted through our proposed SSPR method showed higher P3 responses for the target stimuli than the both SPR and SPR2 methods, which conform to the existing knowledge on P3 responses." } @INPROCEEDINGS{Anej0510:Approximation, AUTHOR="Yash Aneja and Arunita Jaekel and Subir Bandyopadhyay", TITLE="Approximation Algorithms for Traffic Routing in Wavelength Routed {WDM} Networks", BOOKTITLE="BROADNETS 2005 Optical Networking Symposium", DAYS=3, MONTH=oct, YEAR=2005, ABSTRACT="One major objective in WDM network design is to develop a logical topology and a routing that minimizes the congestion of the network. A standard approach is to decouple the problem of logical topology design and the problem of routing on this logical topology. Heuristics for finding the logical topology exist and a straight-forward linear program (LP), based on the node-arc formulation is normally used to solve the routing problem over a given logical topology. We have found that such LP formulations become computationally intractable for large networks. In this paper, we have introduced a novel approach for routing traffic over a given logical topology, using the concept of approximation algorithms. This technique allows us to efficiently route traffic for practical sized networks and obtain solutions, which are guaranteed to be within a specified bound of the optimal solution. Simulation results from different networks demonstrate that approximation algorithms can be used to quickly generate near-optimal solutions to the traffic routing problem in WDM networks." } @INPROCEEDINGS{Ange0502:Impact, AUTHOR="Flavio {De Angelis} and Ibrahim Habib and Fabrizio Davide and Mahmoud Naghshineh", TITLE="The Impact of Revenues on Delivering Differentiated {IP} Multimedia Services in {Wired/Wireless} Networks", BOOKTITLE="3rd International Workshop on QoS in Multiservice IP Networks", ADDRESS="Catania (Italy)", DAYS=2, MONTH=feb, YEAR=2005, ABSTRACT="In this paper, we investigate the impact of the revenues on delivering IP-based multimedia services with different quality of service (QoS) requirements to mobile users. We consider that a network provider offers two distinct classes of services (CoS) to which users may subscribe: Premium, or Economy. A simple revenue model is defined to calculate the total revenue generated due to the traffic downloaded by both types of subscribers. Premium class users pay a higher tariff for their connection to receive a higher level of quality, measured by a set of parameters such as call blocking probability, coding rate, and format of the multimedia services. The delivery of multimedia services is enabled by our proposed QoS-based filtering architecture that guarantees the contractual level of QoS requirements for each type of media (e.g., video, voice and data), while maximizing the links throughput. According to this architecture, filters are installed at the output port of every node of the network and are able to change the coding rates in accordance with the results of a multi-objective optimization function. Simulations results prove that the gain in the number of admitted users is not simply limited by the maximum available link capacity but it is, rather, bounded by the additional revenue gained by admitting those new users. A network provider would not admit additional users above a certain offered traffic-load despite the fact that the multi-objective function results indicate otherwise." } @INPROCEEDINGS{Ange0503:Modified, AUTHOR="Evangelos Angelopoulos", TITLE="A Modified {Bow-Tie} Slot Antenna Fed by a {CPW-to-CPW} Transition Loaded with Inductively Coupled Slots for Ultra Wide - Band Applications", BOOKTITLE="IEEE International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials", ADDRESS="Marina Mandarin Singapore", DAYS=7, MONTH=mar, YEAR=2005, ABSTRACT="This paper introduces a modified coplanar waveguide (CPW)-fed slot printed antenna with asymmetric apertures and inductively coupled slots, aiming towards Ultra Wide-Band (UWB) applications. The proposed module is a miniature shaped, low-profile radiator of medium gain with bi-directional radiation characteristics, which can be optimally embedded in modern UWB transceivers. The incorporation of a tapered CPW-to-CPW transition from Zin = 90 Ohm to Zin = 50 Ohm is introduced as a design novelty of improving the wideband impedance of the radiator, without seriously affecting the overall performance. Furthermore enhancement of the impedance bandwidth is accomplished when inductively fed parasitic slots are inserted in the asymmetric bow-tie slot configuration. Details of the aforementioned design procedure and obtained experimental results exhibiting an impedance bandwidth (VSWR <2) of 123\% are presented." } @INPROCEEDINGS{Ange0511:Delivery, AUTHOR="Flavio {De Angelis} and Ibrahim Habib", TITLE="Multimedia Content Delivery Using Adaptive Filtering in {Time-Varying} {W-CDMA} Networks", BOOKTITLE="Globecom 2005 General Conference", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="In this paper, we present a novel adaptive filtering algorithm for the delivery of multimedia content with different quality of service (QoS) requirements, over time-varying wideband code-division multiple access (W-CDMA) networks. We assume that the service provider offers two distinct grades of service (GoS) to which users may subscribe: Premium, or Economy. Subscribers to the Premium service receive higher multimedia quality levels measured by a set of parameters such as user information rate and format. The proposed algorithm is used to guarantee that all users receive their contractual level of quality while maximizing the radio links throughput, and maintaining the QoS requirements such as maximum transfer delay, target B.E.R, maximum loss and late packets rate for traffic flows (e.g. voice, video, and data) downloaded to the users. Multimedia adaptation filters are installed at the output ports of the radio network controller and manipulate adaptively user information rate and format of each service. Our proposed solution is based upon utilizing Genetic Algorithms (GAs) to solve a multi-objective optimization function that selects, during a control period, the bit rates and format for the media codecs of traffic flow and, at the same time, assigns the air interface channel rate and power subject to different constraints. Simulation results show significant improvement in terms of increasing the number of admitted users while maintaining the maximum delay tolerance and reducing the late and loss packet rates." } @INPROCEEDINGS{Angi0502:Iterative, AUTHOR="Ravi Angiras", TITLE="Iterative Algorithms for Channel Identification Using Superimposed Pilots", BOOKTITLE="2005 Australian Communications Theory Workshop", ADDRESS="Brisbane", DAYS=2, MONTH=feb, YEAR=2005, ABSTRACT="Channel identification of a time varying channel is considered using superimposed training. A sequence of known symbols with lower power is arithmetically added to the information symbols before modulation and transmission. The channel estimation is done exploiting the known superimposed data in the transmitted signal. Two iterative algorithms are considered in this paper: recursive least squares (RLS) and the expectation maximization (EM). Performance of the proposed algorithms is compared with a simple avergaing scheme and the LMS algorihm. Computer simulations are done for all schemes." } @INPROCEEDINGS{Angl0506:Stably, AUTHOR="Dana Angluin and James Aspnes and Melody Chan and Michael J. Fischer and Hong Jiang and Rene Peralta", TITLE="Stably computable properties of network graphs", BOOKTITLE="IEEE International Conference on Distributed Computing in Sensor Systems", ADDRESS="Marina del Rey", DAYS=30, MONTH=jun, YEAR=2005, ABSTRACT="We consider a scenario in which anonymous, finite-state sensing devices are deployed in an ad-hoc communication network of arbitrary size and unknown topology, and explore what properties of the network graph can be stably computed by the devices. We show that they can detect whether the network has degree bounded by a constant d, and, if so, organize a computation that achieves asymptotically optimal linear memory use. We define a model of stabilizing inputs to such devices and show that a large class of predicates of the multiset of final input values are stably computable in any weakly-connected network. We also show that nondeterminism in the transition function does not increase the class of stably computable predicates." } @INPROCEEDINGS{Anib0511:Cross, AUTHOR="Ghassane Aniba and Sonia Aissa", TITLE="{Cross-Layer} Design for Scheduling and Antenna Sharing in {MIMO} Networks", BOOKTITLE="Globecom 2005 Wireless Communications", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="The main important characteristic of an optimal scheduler is to maximize throughput while servicing users in a fair manner. This paper formulates the scheduling problem in MIMO networks as a Generalized Assignment Problem (GAP), and advances a new cross-layer design for the scheduling of users and the assignment of their corresponding data to the available transmit antennas. The proposed scheduling and antenna sharing method, referred to as Fast Transmit Antenna Selection (FTAS) algorithm, uses Adaptive Proportional Fairness (APF) mapping as a means to determine the best user-antenna assignment that maximizes the network performance both in terms of throughput and fairness. The proposed scheduler is applied in a High Speed Downlink Packet Access (HSDPA) network, taking advantage of an inherent HSDPA characteristic, namely, the use of adaptive modulation and coding, while coping with the imposed maximum number of simultaneously supported codes, and the absence of fast power control. Numerical results show that our scheduler provides up to 70\% increase in total throughput compared to other scheduling schemes applied to HSDPA." } @INPROCEEDINGS{AnKy0504:Design, AUTHOR="Hwang AnKyu and JaeYong Lee and ByungChul Kim", TITLE="Design and Performance Evaluation of Maximum Remaining Energy Constrained Directed Diffusion Routing Algorithm for Wireless Sensor Networks", BOOKTITLE="The 15th Joint Conference on Communication \& Information, 2005", ADDRESS="Hotel Inter Burgo, Daegu, Korea", DAYS=27, MONTH=apr, YEAR=2005, ABSTRACT="¼¾¼- ³×Æ®¿öÅ©¸ ±¸¼ºÇÏ´Â °c ³ëµå´Â ´ëü.ÃŽ Å©±â° ÀÛ°í ¹èÅ͸®ÀÇ ¿ë.®ÀÌ ÇÑÁ¤µÇ¾î Àֱ⠶§¹®¿ ¿³ÊÁö ¼Ò¸ð¸ ÁÙÀÌ´Â ¹æ¾ÈÀÌ ¿¬±¸µÇ°í ÀÖ´Ù. ³ëµå´Â ÀÚ½ÅÀÇ À§Ä¿ µû¶ó¼- À̺¥Æ® °¨Áö¿Í µ¥ÀÌÅÍ Àü¼Û Ƚ¼öµî¿ ÀÇÇØ ´Ù¸¥ ³ëµå¿Í ¼-.ÃŽ ´Ù¸¥ ¿³ÊÁö ¼ÒºñÀ²À» º¸ÀÏ ¼ö ÀÖÀ¸¸ç ³ëµå°£ÀÇ ¼ö¸íµµ ´Ù¸£°Ô µÈ´Ù. µû¶ó¼- ƯÁ¤ ³ëµåÀÇ ¼ö¸í ´ÜÃàÀ¸.ÃŽ ÀÎÇØ Àüü ³×Æ®¿öÅ©¿ ´ëÇÑ ¸ÁÀÇ ¼ö¸íÀ» ´ÜÃà½Ãų ¼ö ÀÖ´Ù. º» ³í¹®¿¼-´Â ¼¾¼- ³×Æ®¿öÅ©¿¼- µ¥ÀÌÅÍ Àü¼ÛÀ» À§ÇÑ °æ.ÃŽ ¼±Åÿ ÀÖ¾î ³²¾ÆÀÖ´Â ¿³ÊÁö° ¸¹Àº ³ëµå Áß¿ ÃÖ¼Ò ¿³ÊÁö¸ ¼Ò¸ðÇÏ´Â °æ.θ ¼±ÅÃÇÔÀ¸.νá ¸ÁÀÇ ¼ö¸íÀ» ¿¬ÀåÇÏ°í ÀüüÀûÀÎ ¿³ÊÁö ¼ÒºñÀ²ÀÌ ºñ½ÁÇÏ°Ô À¯ÁöÇÏ´Â ¶ó¿ìÆà ¾Ë°í¸®ÁòÀ» Á¾ÈÇÏ¿´´Ù. Á¾ÈµÈ ¾Ë°í¸®ÁòÀÇ ¸ñÀûÀº ¼¾¼- ³×Æ®¿öÅ©ÀÇ ¼ö¸íÀ» ¿À. À¯ÁöÇϴµ¥ ÀÖÀ¸¸ç ½Ã¹Ä.¹À̼ÇÀ» ÅëÇØ ±âÁ¸¿ Á¾ÈµÈ ¶ó¿ìÆà ¾Ë°í¸®Áò°úÀÇ ¼º´É ºñ±³¸ ÅëÇØ È¿À²¼ºÀ» º¸¿´´Ù." } @INPROCEEDINGS{AnKy0504:Modified, AUTHOR="Hwang AnKyu and ByungChul Kim and JaeYong Lee and Jae-Hwoon Lee and Chang MyongRae", TITLE="Modified snoop protocol Design for {TCP} Performance Enhancement to Handover in {FHMIPv6}", BOOKTITLE="The 15th Joint Conference on Communication \& Information, 2005", ADDRESS="Hotel Inter Burgo, Daegu, Korea", DAYS=27, MONTH=apr, YEAR=2005, ABSTRACT="FHMIPv6´Â À̵¿´Ü¸»ÀÌ handover½Ã?Áö¿¬½Ã°£°ú ÀÚ¿ø¼Òºñ?ÁÙÀ̱â À§ÇÑ HMIPv6¿Í ÆÐŶ ¼Õ½ÇÀ» ÁÙÀ̱â À§ÇÑ fast handover¾Ë°í¸®ÁòÀÇ ÀåÁÀ?°®´Â´Ù. Fast handover¾Ë°í¸®ÁòÀº handover½Ã?ÀÌÀü ¶ó¿ìÅÍ.?Àü¼ÛµÇ´Â ÆÐŶÀ» ÅͳθµÀ» ÅëÇØ »õ.ο?¶ó¿ìÅÍ.?Àü¼ÛÇØ ÁÜÀ¸.ν?ÆÐŶ ¼Õ½ÇÀ» ÁÙÀÏ ¼ö ÀÖÁö¸¸, Åͳθµ µÇ¾î? Àü¼ÛµÇ´Â ÆÐŶ°ú Á÷Ác Àü¼ÛµÇ´Â ÆÐŶÀÇ ¼ø??µÚ¹Ù²î¾î TCP¼º´ÉÀ» ÀúÇϽÃÅ°´Â ¹®ÁÁÀ» °Áö°?ÀÖ´Ù. º» ³í¹®¿¼-´Â snoop ÇÁ.ÎÅäÄÝÀ?žÀçÇÑ ¶ó¿ìÅÍ?°£´ÜÇÑ ¾Ë°í¸®ÁòÀ» Ãß°ÇÏ¿?fast handover¿¼- ¹ß»ýÇÒ ¼ö ÀÖ´Â µ¥ÀÌÅÍ ¼¼±×¸ÕÆ®ÀÇ ¼ø? ¾î±ß³² Çö»óÀ» ¹æÁöÇÔÀ¸.ν?TCP¼º´ÉÀ» Çâ»ó ½Ãų ¼ö ÀÖ´Â resequencing¾Ë°í¸®ÁòÀ» Á¾ÈÇÏ¿´´? ¶ÇÇÑ ½Ã¹Ä.¹À̼ÇÀ?ÅëÇØ ±âÁ¸ FHMIPv6°ú ¼º´ÉÀ» ºñ±³ ºÐ¼®ÇÏ¿´´Ù." } @INPROCEEDINGS{AnKy0504:Resequencing, AUTHOR="Hwang AnKyu and JaeYong Lee and ByungChul Kim and Jae-Hwoon Lee and Chang MyongRae", TITLE="Resequencing Algorithm Design for {TCP} Performance Enhancement to Handover in {FHMIPv6}", BOOKTITLE="The 15th Joint Conference on Communication \& Information, 2005", ADDRESS="Hotel Inter Burgo, Daegu, Korea", DAYS=27, MONTH=apr, YEAR=2005, ABSTRACT="Mobile IPv6¿¼- À̵¿´Ü¸»ÀÌ À̵¿ÇÒ ¶§ handover¿ ÀÇÇؼ- ÆÐŶÀÌ ¼Õ½ÇµÇ´Â ´ÜÁÀ» º¸¿ÏÇϱâ À§Çؼ- fast handover ¾Ë°í¸®ÁòÀÌ Á¾ÈµÇ¾ú´Ù. Fast handover ¾Ë°í¸®ÁòÀº À̵¿´Ü¸»ÀÌ À̵¿Çؼ- »ç¿ëÇÒ mobile IP¸ handover ÀÌÀü¿ ¾òÀ½À¸.νá handover ½Ã°£À» ´ÜÃàÇÒ ¼ö ÀÖ°í, handover½Ã¿ ÆÐŶÀÌ ÀÌÀü ¶ó¿ìÅÍ¿¼- »õ.οî ¶ó¿ìÅÍ.ÃŽ ÅͳθµµÇ¾î Àü¼ÛµÇ¾î ÆÐŶ ¼Õ½ÇÀ» ÁÙÀÏ ¼ö ÀÖ´Ù. ¹Ý¸é ÆÐŶÀÇ ¼ø¼-° µÚ¹Ù²î´Â ¹®ÁÁÀÌ ¹ß»ýÇÏ°Ô µÇ°í ÀÌ.ÃŽ ÀÎÇØ TCP¼º´ÉÀÌ ÀúÇϵȴÙ. º» ³í¹®Àº FLUSHÆÐŶÀ» ÀÌ¿ëÇÏ¿© À̵¿ ´Ü¸»ÀÌ À̵¿°£ Åë½ÅÀ» ÇÒ °æ¿ì FHMIPv6½Ã¿ ÆÐŶ ¼ø¼-ÀÇ µÚ¹Ù²ñ ¹®Á¸ ÇØ°á ÇÔÀ¸.νá TCPÀÇ ¼º´ÉÀ» Çâ»ó ½Ãų ¼ö ÀÖ´Â resequencing ¾Ë°í¸®ÁòÀ» Á¾ÈÇÏ¿´´Ù. ¶ÇÇÑ ½Ã¹Ä.¹À̼ÇÀ» ÅëÇØ ±âÁ¸ÀÇ FHMIPv6¿Í ºñ±³ ºÐ¼®ÇÏ¿´´Ù." } @INPROCEEDINGS{Anli0505:Design, AUTHOR="Urs Anliker and Holger Junker and Paul Lukowicz and Gerhard {Tröster}", TITLE="Design Methodology for context-aware wearable sensor systems", BOOKTITLE="Pervasive 2005 - Third Intl. Conf. on Pervasive Computing", ADDRESS="Albrecht Schmidt, University of Munich", DAYS=8, MONTH=may, YEAR=2005, ABSTRACT="Many research projects are dealing with context-aware wearable systems. We see always the same issues reoccurring, e.g. where to put the sensors, which features to use and how to organize the system. We seek to formalize these commonalities and to automate the design process. In this paper, we present a modelling and evaluation methodology to optimize the design of context-aware, wearable computer systems that rely on information from multiple, body-worn sensors. Based on a standard recognition task for wearable computers, we show how to apply our evaluation methodology to derive an optimized design for a wearable sensor system and finally present first quantitative results." } @INPROCEEDINGS{Anna0511:Development, AUTHOR="Uma Annaiyan and Kourosh Kalantar-Zadeh and John {Quang Fang} and Irena Cosic", TITLE="Development of a conductive photoresist with a mixture of {SU-8} and {HCl} doped polyaniline", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="A novel electrically conductive photoresist has been formulated to fabricate microcomponents. The developed conductive photoresist is based upon SU-8 photopolymer, an insulating negative-tone epoxy, in which protonically doped polyaniline (PANI) nanoparticles have been dispersed to enhance the electrical properties. The characteristics of this new conductive photoresist have been studied via electrical measurements. The process for preparing the conductive films from the combination of EB (Emeraldine base) PANI, SU-8 and NMP (N-methyl-2-pyrrolidinone) will be presented. Different weight percentages (wt \%) of SU-8 in the above combination have been prepared and spin coated to form thin-films which have been protonated with HCl. The conductivities of the thin-films were measured using a four point probe. The highest conductivity achieved was approximately 1.6 S/cm for the mixture of 10wt\% of SU-8 25 with EB-PANI mixed with NMP. The morphology of the thin-films was studied using a Scanning Electron Microscopy (SEM)." } @INPROCEEDINGS{Anne0509:Inter, AUTHOR="Deleuze Anne-Laure and Philippe Ciblat and Christophe J. {Le Martret}", TITLE="{Inter-Symbol} / {Inter-Frame} Interference in {Time-Hopping} Ultra Wideband Impulse Radio System", BOOKTITLE="2005 IEEE International Conference on Ultra-Wideband", ADDRESS="Zurich", DAYS=5, MONTH=sep, YEAR=2005, ABSTRACT="A closed-form expression for the inter-symbol / inter-frame interference variance is derived in the context of a time-hopping ultra wideband impulse radio based system. This enables us to theoretically analyze the influence of the time-hopping codes, the rake receiver number of fingers, and the size of the guard time on the performance. Simulations sustain our claims." } @INPROCEEDINGS{Anou0505:Self, AUTHOR="Hicham Anouar and Christian Bonnet", TITLE="A {Self-Balanced} {Receiver-Oriented} {MAC} Protocol for Multiple channels Multihop {Ad-Hoc} Networks", BOOKTITLE="Vehicular Technology Conference Spring 2005 Wireless Access", ADDRESS="Stockholm, Sweden", DAYS=28, MONTH=may, YEAR=2005, ABSTRACT="In this work, we present SEBROMA, a realistic and fully distributed multiple access protocol for multiple channels ad hoc networks. The basic philosophy of the developed scheme is to reduce as much as possible signalization overhead and avoid global network synchronization due to the difficulties related to its practical realization. To minimize collisions at high loads, each communication is initiated by receivers. Code division multiple access scheme is used, where a common code is used for signalization and other codes are used randomly by all nodes for communications. This simplifies the code assignment functionality since no inter-node collaboration is needed. In SEBROMA, each node alternates fairly between transmission and reception phases until successful delivery of packets, this allows to unlock situations where numerous transmitters are trying to initiate simultaneously a communication, which keep all of them blocked infinitely. The proposed scheme is analyzed through Markov chains modeling and simulated under NS2, throughput and delay obtained are stable regardless of network load." } @INPROCEEDINGS{Ansa0506:Parallel, AUTHOR="Bijan Ansari and Huapeng Wu", TITLE="Parallel computation of scalar multiplication for elliptic curve cryptosystem", BOOKTITLE="Canadian Workshop on Information Theory", ADDRESS="Montreal, Quebec", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="In this paper, parallel algorithm and architecture for computing scalar multiplication for elliptic curve cryptosystems are proposed. The proposed multiprocessor architecture assumes one processor performs point doubling operations and the rest processors compute point addition operations. The total number of processors required depends on the ratio between the times taken to compute a point addition and a point doubling on a single processor. Let the above mentioned ratio be denoted as $r$. We show that a dual-processor system computes scalar multiplication efficiently when r<=3. When r>=4, a system of three processors can achieve high performance. Security issue against the side channel attack is addressed. This multiprocessor architecture can also be used for efficient computation of exponentiation." } @INPROCEEDINGS{Anti0502:Robust, AUTHOR="Johanna Nieminen and Marko Luoma", TITLE="Robust delay estimation of an adaptive scheduling algorithm", BOOKTITLE="3rd International Workshop on QoS in Multiservice IP Networks", ADDRESS="Catania (Italy)", DAYS=2, MONTH=feb, YEAR=2005, ABSTRACT="In this paper we propose three new packet delay estimators for an adaptive, delay-bounded HPD (DBHPD) scheduling algorithm in the DiffServ context: simple Exponential Weighted Moving Average (EWMA) estimator, EWMA estimator with restart (EWMA-r) and EWMA based on proportional error of the estimate (EWMA-pe). We compare these estimators with the original, simple sum estimator with ns2-simulations using several traffic mixes. We show that the simple sum and EWMA estimators often lead to false scheduling decisions. On the other hand, the EWMA-r and especially the EWMA-pe estimator provide good estimates of the packet delay regardless of the traffic mix." } @INPROCEEDINGS{Anto0505:Analog, AUTHOR="Nigel Antoine", TITLE="Analog Voltage Squarer", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="An Analog Voltage Squarer (AVS) designed at Carleton University for Pre-distortion in Radio-Over-Fiber Communications to produce 2nd order terms on a 2nd order path, is described. This design can be used to square analog signals of high frequency (GHz range) and low voltages. AVS was implemented using the square law characteristics of the MOS device operating in the saturation region. The AVS was designed using three essential components; a Squaring Device, a Source-Follower and a Current-to-Voltage (I-to-V) Converter." } @INPROCEEDINGS{Anto0509:65279, AUTHOR="Nicolò Antonietti and Guido Pagana", TITLE="\The {PICPOT} experiment: {GPS} and {GALILEO} in High dynamic Scenario", BOOKTITLE="International Workshop on Satellite and Space Communications 2005", ADDRESS="Siena, Italy", DAYS=8, MONTH=sep, YEAR=2005, ABSTRACT="Abstract:The introduction of GPS has represented a revolution in both military and civil field. While commercial GPS receivers are able to track objects moving at low velocities (hundreds of kilometres per hour), space applications require special adjustments that allow the tracking system to localize objects moving at high velocities (few kilometres per second) called High Dynamics applications, due to the high relative motion between the object on which the receiver is installed and the GPS Satellites. GALILEO, which represents the European initiative in the field of GNSS (Global Navigation Satellite Systems) is conceived as a civil system for earth applications. Nonetheless, it is possible to introduce some questions on its possible space applications. Scope of the work is the study of the characteristics of a GAILLEO receiver, compatible with high dynamics (HD) scenarios and especially conceived for working in a space environment, its pros and cons with respect to the GPS signal." } @INPROCEEDINGS{ANWA0509:Simplified, AUTHOR="Khoirul Anwar and Masato Saito and Takao Hara and Minoru Okada and Heiichi Yamamoto", TITLE="Simplified Realization of {Pseudo-Orthogonal} Carrier Interferometry {OFDM} by {FFT} Algorithm", BOOKTITLE="5th Int'l. Workshop on Multi-Carrier Spread Spectrum", ADDRESS="Oberpfaffenhofen, Germany", DAYS=14, MONTH=sep, YEAR=2005, ABSTRACT="This paper proposes new design for realizing Pseudo-orthogonal Carrier Interferometry Orthogonal Frequency Division Multiplexing (PO-CI/OFDM) system by utilizing FFT algorithm as a substitute of PO-CI spreading/despreading process. We also propose a separator design for guaranteeing that the resulted codes are still (pseudo) orthogonal to each other. These solutions can reduce the complexities of PO-CI/OFDM implementation significantly. Difficulties of generating PO-CI codes as a complex code are successfully solved by employing two IFFT/FFTs with the proposed separator. In this paper, we show that PO-CI/OFDM using FFT algorithm (further called PO-CI-FFT/OFDM) is a very simple and low cost technique while providing good performance as the original PO-CI/OFDM. Additional multiplications and additions for PO-CI generating and spreading, then additional memory for storing the generated codes is not required when utilizing the proposed design. This solution is then capable in making PO-CI/OFDM closer to the reality." } @TECHREPORT{Anwa0510:Leveraging, AUTHOR="Zahid Anwar and William Yurcik and Vivek Pandey and Asim Shankar and Indranil Gupta and Roy Campbell", TITLE="Leveraging {Social-Network} Infrastructure to Improve {Peer-to-Peer} Overlay Performance: Results from Orkut", TYPE="arXiv report", INSTITUTION="arXiv", NUMBER="cs.NI/0509095", MONTH=oct, YEAR=2005, ABSTRACT="Application-level peer-to-peer (P2P) network overlays are an emerging paradigm that facilitates decentralization and flexibility in the scalable deployment of applications such as group communication, content delivery, and data sharing. However the construction of the overlay graph topology optimized for low latency, low link and node stress and lookup performance is still an open problem. We present a design of an overlay constructed on top of a social network and show that it gives a sizable improvement in lookups, average round-trip delay and scalability as opposed to other overlay topologies. We build our overlay on top of the topology of a popular real-world social network namely Orkut. We show Orkuts suitability for our purposes by evaluating the clustering behavior of its graph structure and the socializing pattern of its members.", URL="http://arxiv.org/abs/cs/0509095" } @INPROCEEDINGS{Anwa0511:Achieving, AUTHOR="Zahid Anwar", TITLE="Achieving Call Survivability in Cellular Networks", BOOKTITLE="The 30th Annual IEEE Conference on Local Computer Networks (LCN)", ADDRESS="Syndey, Australia", DAYS=15, MONTH=nov, YEAR=2005, ABSTRACT="Cellular phones are become increasingly popular with more and more carriers stomping the market. Technologies such as Digital, Analog, GSM are giving way to TDMA and CDMA. Multiple frequencies are supported e.g. new tri-band phones utilize 900MHz, 1800MHz and 1900Mhz. Despite all the new features such as added battery life, privacy and interoperability the survivability of the call is still a large issue. Important business calls and telephonic interviews cannot benefit from mobility because landlines are preferred owing to their reliability and tolerance to failures. In this paper we present a framework to improve call survivability by monitoring the users location and intimating him about the possibility of loss of connectivity, interference and room schedules that might disrupt conversation. In addition if a call drops because of unforeseeable circumstances like battery failure or cell-phone damage then the call is switched to the nearest device available and capable of streaming voice." } @INPROCEEDINGS{Aoki0505:Development, AUTHOR="Naofumi Aoki", TITLE="Development of a {VoIP} system implementing a high quality packet loss concealment technique", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Speech quality of VoIP (Voice over Internet Protocol) may potentially be degraded by transmission errors such as packet loss and delay which are basically inevitable in best-effort communications. This study investigates an error concealment technique for such degradation by using a receiver-based technique called pitch waveform replication (PWR). PWR repairs a gap frame by copying repeatedly a pitch waveform until the gap is filled. Since the pitch waveform, which is obtained from the backward frame of the gap, is only employed in the conventional PWR, speech quality may potentially be degraded by both phase and envelope mismatches between the repaired frame and its forward frame. In order to alleviate this problem, we have proposed two-side PWR. It takes account of the waveform reconstruction from the forward frame of the gap as well as the backward one. However, in the conventional two-side PWR, coherency of the pitch waveforms between the backward and forward frames is not well taken into consideration, so that phase mismatches may occur inside the repaired frames. For enhancing the two-side PWR, this study investigates a waveform reconstruction technique that also takes account of the pitch variation between the backward and forward frames. From experimental results of objective evaluation, it is indicated that the proposed technique may potentially be useful for improving the speech quality, compared with the conventional technique. In addition, this study has also developed a VoIP system that implements the proposed error concealment technique. This real-time embedded system employs Renesas H8 as a microprocessor for performing the whole of the digital signal processing, such as speech compression and decompression as well as the proposed error concealment technique. In this system, NOTASIP (Nothing Other Than A Simple Internet Phone) is implemented as a session management protocol for realizing P2P (peer-to-peer) speech communications. Because of implementing the proposed error concealment technique, the system outperforms the conventional one in speech quality." } @INPROCEEDINGS{AOKI0505:Photoluminescence, AUTHOR="Takeshi Aoki", TITLE="Photoluminescence Lifetime Distributions in Amorphous, Porous and Organic Semiconductors; {Wide-Band} Quadrature Frequency Resolved Spectroscopy Extending over 11 Decades in Lifetime", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="A newly developed wide-band quadrature frequency resolved spectroscopy (QFRS) allowing analysis of photoluminescence (PL) lifetime over almost 11 decades (from 2ns to 160 s) is outlined. Using this technique, we have found a third new peak in not only hydrogenated amorphous Si (a-Si:H) but also a-Ge:H in addition to well-know double peaks at a low temperature and a low photocarrier generation rate G. Its dependence on the generation rate G suggests that the third peak originates from distant-pair or nongeminate recombination, and geminate and nongeminate recombination coexists even under the geminate recombination condition of G<10^19cm-3s-1. We also show that temperature and magnetic field dependences of the PL lifetime distributions attribute the third peak to the nongeminate recombination and the double peaks to the singlet- and triplet-excitonic (geminate) recombination in both a-Si:H and a-Ge:H. Furthermore similar PL lifetime distributions of chalcogenides semiconductors such as g-AsS, a-AsSe and a-Se are presented. Results of the wide-band QFRS for porous Si and organic semiconductor such as Ir(ppy)3 having triplet excitonic recombination are also briefly demonstrated." } @INPROCEEDINGS{Aoua0503:MPLS, AUTHOR="Hazar Aouad and Samir Tohme", TITLE="Using network tomography for dynamic path adaptation", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="This paper proposes a new fast algorithm to evaluate the probability distribution function (PDF) of link delay over time by using network tomography techniques. Once we have the distribution of the delay we can adapt the route of the flows between a source and its destination so that the end-to-end path is always the one that offers the least mean delay and a probability of exceeding a critical value smaller than a predefined threshold. Our mechanism, which guarantees the use of the path minimizing the end-to-end delay, is best implemented in the core network of a wireless domain. As the network tomography introduces additional flows, our mechanism is more adapted to wired peer ends, e.g. base stations, domain gateways... With the MPLS (Multi Protocol Label Switching) protocol to create and maintain the routes, we validated our contribution using the Network Simulation simulator NS2 ([\‎10])." } @INPROCEEDINGS{AOYA0503:Handover, AUTHOR="Tetsuya Aoyama and Koichi Ishibashi and Masaki Bandai and Masahiro Kuroda and Takashi Watanabe", TITLE="Handover Latency Analysis on Mobile Ethernet", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="Mobile Ethernet is one of mobility management architectures for integrating future heterogeneous wireless systems. This paper gives qualitative comparison of Mobile Ethernet architecture with other mobility supports. For a quantitative analysis, we give an analytical network model through a Markovian model. To evaluate the handover latency of Mobile Ethernet as well as three other mobility supports, the sequence of location update formulates the handover latency. The handover latency and the degree of confusion is compared with each other. From the numerical result, Mobile Ethernet achieves small handover latency and high scalability in case of handover depending on service rates of switches and capacities of links." } @INPROCEEDINGS{Apos0506:State, AUTHOR="George Apostolopoulos and Ioana Ciurea", TITLE="State Efficient {Point-to-Multipoint} Trees using {MPLS} Multicast", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="IP multicast was created in order to enable more efficient usage of network resources for applications that require group communications. Many years after its initial development, IP multicast is not widely used in the Internet today. One of the main roadblocks to the adoption of multicast is the potentially large forwarding state that multicast routers will have to maintain and the difficulty in aggregating this state. In addition to the well known applications, new technologies create new opportunities for multicast. A good example are the various types of virtual private networks (VPNs) applications that require tunneling of user data over the packet backbones of service providers. In this work we will investigate how the problem of multicast state scalability re-emerges in the VPN setting and how it can be effectively addressed there using the MPLS label based forwarding paradigm." } @INPROCEEDINGS{Appa0509:Comis, AUTHOR="Sai Apparao", TITLE="{COMiS} : Component Oriented Middleware for Sensor Networks", BOOKTITLE="14th IEEE Workshop on Local and Metropolitan Area Networks", ADDRESS="Chania, Greece", DAYS=18, MONTH=sep, YEAR=2005, ABSTRACT="Recent advances in wireless technology have enabled the rapid development of wireless sensor networks. Such networks, consisting of tens to thousands of randomly deployed nodes collaborating to achieve a goal, are used in a variety of applications. However, due to extreme resource constraints and lack of suitable programming abstractions, programming sensor networks becomes a tedious process. This coupled with the event driven nature of applications necessitates different programming paradigms for the middleware design. Literature survey shows that existing middleware are application specic. This is due to peculiar characteristics of sensor networks(such as, nodes are prone to failures, restricted resources, etc). A generic middleware is required to develop a wide variety of applications in an efcient manner. So there is a strong need for a generic middleware rather than application specic one. This paper presents a generic middleware known as COMiS(Component Oriented Middleware for Sensor Networks). The middleware(COMiS) is developed in terms of components, to satisfy the resource constraints such as memory and power. The components of middleware may be different at different nodes based on the functionality. So components are loaded into memory based on the application semantics. COMiS also provides services such as discovering k components, discovering components within distance , registration, component updation, power management, etc. This paper discusses the design and implementation of COMiS middleware. This paper also presents the comparison of existing middleware with respect to programming ease, modularity, adaptability and code size." } @TECHREPORT{Arab0504:Hybrid, AUTHOR="Knarig Arabshian and Henning Schulzrinne", TITLE="Hybrid Hierarchical and {Peer-to-Peer} Ontology-based Global Service Discovery System", INSTITUTION="Columbia University", NUMBER="CUCS-016-05", MONTH=apr, YEAR=2005, ABSTRACT="Current service discovery systems fail to span across the globe and they use simple attribute-value pair or interface matching for service description and querying. We propose a global service discovery system, GloServ, that uses the description logic Web Ontology Language (OWL DL). The GloServ architecture spans both local and wide area networks. It maps knowledge obtained by the service classification ontology to a structured peer-to-peer network such as a Content Addressable Network (CAN). GloServ also performs automated and intelligent registration and querying by exploiting the logical relationships within the service ontologies.", URL="http://www1.cs.columbia.edu/~library/TR-repository/reports/reports-2005/cucs-016-05.pdf" } @INPROCEEDINGS{Arab0506:Gloserv, AUTHOR="Knarig Arabshian and Henning Schulzrinne and Dirk Trossen and Dana Pavel", TITLE="{GloServ:} Global Service Discovery using the {OWL} Web Ontology Language", BOOKTITLE="IEE International Workshop on Intelligent Environments (IE05)", ORGANIZATION="IEE", MONTH=jun, YEAR=2005, ABSTRACT="Due to the growth in ubiquitous computing technology in the past few years, the need for context-aware service discovery across wide area networks is becoming prevalent. Current service discovery protocols lack in the ability to scale to large networks as well as semantically describe services. Thus, we propose GloServ, which is a global service discovery architecture that locates services throughout wide and local area networks. Intelligent agents within GloServ use the OWL Web Ontology Language to provide detailed service descriptions, and provide users with automatic registration and querying. This paper discusses a revision of GloServ that uses the OWL Web Ontology Language, as its ontology for describing services instead of the Resource Description Framework Schema (RDFS). We will describe how OWL is used for automated registration and querying of services throughout a global network.", URL="http://www1.cs.columbia.edu/~knarig/gloservRevised.pdf" } @INPROCEEDINGS{Arac0506:Minmax, AUTHOR="Javier Aracil and Daniel Morato and Eduardo {Magaña} and Mikel Izal", TITLE="{MinMax} Bandwidth Allocation for Time-slotted Systems with Internet Traffic", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="The MinMax scheduling algorithm has been proved to be fair and efficient for dynamic bandwidth allocation in wireless scenarios. In this paper, MinMax is extended to the case of Internet traffic, which is bursty at all timescales. To do so, MinMax is equipped with a minimum square error estimate in order to improve bandwidth allocation accuracy. The proposed MinMax extension is named MinMaxPred, which has been developed following a novel methodology that considers the traffic prediction and bandwidth scheduling problem jointly while, traditionally,they were considered as isolated problems." } @INPROCEEDINGS{ARAI0511:Embedded, AUTHOR="Tomoyuki Arai and Koji Kamakura and Kenichiro Yashiro", TITLE="Use of Turbo Coding for Embedded Transmission Scheme in Optical {CDMA}", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="We propose using turbo code for the embedded transmission (ET) scheme in optical code division multiple access (CDMA). Although the scheme uses pulse position modulation (PPM), to resolve the problem of the vulnerability of the embedded PPM signaling to multiple access interference (MAI), we obtain soft information of the received signal, which is used for turbo decoding. We evaluate the bit error rate (BER) of the proposed scheme, compared the conventional PPM-OCDMA with turbo coding and the ET scheme with BCH coding. Simulation results show that the conventional turbo-coded PPM-OCDMA and than the BCH-coded ET scheme." } @INPROCEEDINGS{Arak0509:Channel, AUTHOR="Naoyuki Araki and Hiroyuki Yashima", TITLE="A Channel Model of Optical Wireless Communications during Rainfall", BOOKTITLE="ISWCS 2005 Main Symposium", ADDRESS="Siena, Italy", DAYS=5, MONTH=sep, YEAR=2005, ABSTRACT="Optical wireless communication systems have the potential to provide large-bandwidth communication. A high-speed communication system can be constructed at low-cost and short times; this is one of the effective means to straighten out the last one mile problem. On the other hand, the propagation characteristic changes greatly by the change in the communication environment of meteorological conditions etc.. In this paper, we propose a channel model of optical wireless propagation during rainfall. A probability density function (p.d.f.) of the received signal power is theoretically derived and its validity is confirmed with experimental results." } @INPROCEEDINGS{Arau0506:Use, AUTHOR="Ricardo {de Araujo} and Favier {Gérard} and João Cesar Mota and Charles Casimiro Cavalcante", TITLE="The use of orthonormal bases in equalization structures", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="In this work we propose the use of an ARMA equalizer structured on generalized orthonormal bases for communication purposes. This equalizer structure presents a tapped line of all-pass and low-pass filters. Such a structure is inherently stable since all its poles are within the unit circle. We also discuss a method for bases parameterizing (poles choice) based on the channel characteristics. The proposed structure performances are compared with conventional FIR equalizer ones. The results are evaluated in terms of MSE and overall numerical complexity. Traditional trained algorithms are employed for filter weight adapting. Our simulations show that the proposed structure leads to enhanced performances offering an alternative reduced complexity solution for communication channel equalization problem." } @INPROCEEDINGS{Arba0505:Estimating, AUTHOR="Ehsan Arbabi and Mohammad Bagher Shamsollahi and Shahab Oveisgharan", TITLE="Estimating Effect of Noise Related to Inexact Sampling of Deterministic Signals in Practical {A/D} Converters", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="In Analog to Digital Converters, sampled values of the input continuous signal are not necessarily sampled in the desired sampling times. That means the sampling process may occur slightly before or after the desired sampling times because of using non ideal converters. According to this fact, output signals of converters contain noises related to the inexact time sampling which can make us far from the mathematically calculated sampled signals. Therefore, in order to have much more accurate calculations for process(es) which may be applied on time-sampled signals, we need to have an estimation of the maximum effect of the noise resulted from practical time-sampling. In this paper, signal to noise ratio according to inexact practical time-sampling of real continuous signal will be estimated. For this estimation, we have assumed the continuous signal which is going to be sampled, as a zero-mean real deterministic signal which also satisfies the Nyquist sampling rate assumption. In fact we will estimate the signal to sampling-noise ratio by considering that our knowledge about the input signals is limited to the above conditions. By applying mathematical calculations and estimating signal to sampling-noise ratio, a minimum boundary for signal to sampling-noise is obtained as a function of the variance of the sampling error. Finally it will be concluded that what kind of condition are sufficient to be applied in order to have a desirable minimum ratio of signal to sampling-noise." } @INPROCEEDINGS{Arda0505:Gear, AUTHOR="Masoud Ardakani and Frank Kschischang", TITLE="Gear-shift Decoding for Algorithms with Varying Complexity", BOOKTITLE="ICC 2005 Communication Theory", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="We consider an iterative message-passing decoder that can choose its decoding rule among a group of decoding algorithms at each iteration (for example: a software decoder). Each available decoding algorithm may have a different computation time and performance. We first show that with proper choice of algorithm at each iteration, decoding latency can significantly be reduced. We call such a decoder a gear-shift decoder because it changes its decoding rule (shifts gear) in order to guarantee both convergence and minimum decoding-latency. We also prove that the optimum gear-shift decoder (the one with the minimum decoding-latency) has a decoding threshold equal to or better than the best decoding threshold of the available algorithms. We use extrinsic information transfer charts and dynamic programming to find the optimum gear-shift decoder. For hardware decoders that should provide a given throughput, we propose a pipeline structure and optimize the gear-shift decoder to achieve minimum hardware cost." } @INPROCEEDINGS{Arda0509:Complexity, AUTHOR="Wei Yu and Masoud Ardakani and Benjamin Smith and Frank Kschischang", TITLE="{Complexity-Optimized} {Low-Density} {Parity-Check} Codes for Gallager Decoding Algorithm B", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="The complexity-rate tradeoff for error-correcting codes below the Shannon limit is a central question in coding theory. This paper makes progress in this area by presenting a joint numerical optimization of rate and decoding complexity for low-density parity-check codes. The focus of this paper is on the binary symmetric channel and on a class of decoding algorithms for which an exact extrinsic information transfer (EXIT) chart analysis is possible. This class of decoding algorithms includes the Gallager decoding Algorithm B. The main feature of the optimization method is a complexity measure based on the EXIT chart that accurately estimates the number of iterations required for the decoding algorithm to reach a target error rate. Under a fixed check-degree distribution, it is shown that the proposed complexity measure is a convex function of the variable-degree distribution in a region of interest. This allows us to numerically characterize the complexity-rate tradeoff. We show that for the Gallager B decoding algorithm on binary symmetric channels, the optimization procedure can produce complexity savings of 30-40\% as compared to the conventional code design method." } @INPROCEEDINGS{Argy0504:AXP, AUTHOR="Patroklos Argyroudis", TITLE="{AXP:} Authorization eXchange Protocol", BOOKTITLE="International Workshop on Systems and Network Security", ADDRESS="Denver, Colorado", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="In this paper we propose a new protocol for handling the exchange and negotiation of authorization information in distributed networking environments. Although during the last years there have been a lot of proposals in the literature for systems that attempt to manage trust establishment, the engineering details related to the exchange and negotiation of authorization credentials have not received similar attention. The Authorization eXchange Protocol (AXP) provides a modular and extensible solution to this problem. It is situated between the application and the network layer, handling the process of transmitting and receiving service access requests and replies, along with the credentials that are required to support them. In order to allow its use in securing delay sensitive applications, AXP has been designed to work over unreliable datagram transport protocols." } @TECHREPORT{Argy0504:Scalable, AUTHOR="Tassos Argyros and David Cheriton", TITLE="A Scalable {Stream-Oriented} Framework for Cluster Applications", TYPE="arXiv report", INSTITUTION="arXiv", NUMBER="cs.DC/0504051", MONTH=apr, YEAR=2005, KEYWORDS="Distributed, Parallel, and Cluster Computing; Databases; Networking and Internet Architecture; Operating Systems; Programming Languages", ABSTRACT="This paper presents a stream-oriented architecture for structuring cluster applications. Clusters that run applications based on this architecture can scale to tenths of thousands of nodes with significantly less performance loss or reliability problems. Our architecture exploits the stream nature of the data flow and reduces congestion through load balancing, hides latency behind data pushes and transparently handles node failures. In our ongoing work, we are developing an implementation for this architecture and we are able to run simple data mining applications on a cluster simulator.", URL="http://arxiv.org/abs/cs/0504051" } @INPROCEEDINGS{Argy0506:Towards, AUTHOR="Patroklos Argyroudis", TITLE="Towards Flexible Authorization Management", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="During the last years there have been a lot of proposals in the literature for systems that attempt to manage the process of trust establishment. However, the engineering details related to the exchange and negotiation of authorization credentials have not received similar attention. Existing solutions like SSL/TLS and IPsec have limitations that minimize their applicability. In this paper we propose a new protocol, the Authorization eXchange Protocol (AXP), that pro-vides a modular and extensible solution to this problem. It is situated between the application and the network layers acting as an authorization middleware component and handles the process of transmitting and receiving service access requests and replies, along with the credentials that are required to support them. In order to allow its use in securing delay sensitive applications, AXP has been designed to work over unreliable datagram transport protocols. We also present a case study and evaluate the performance of our proposal." } @INPROCEEDINGS{Aria0509:Synchronization, AUTHOR="Eva Arias-de-Reyna and José Acha", TITLE="Synchronization of {UWB} signals in the dense multipath channel based on the golden section", BOOKTITLE="2005 IEEE International Conference on Ultra-Wideband", ADDRESS="Zurich", DAYS=5, MONTH=sep, YEAR=2005, ABSTRACT="The problem of coarse synchronization of Ultra Wideband signals in the dense multipath channel is addressed. When the classical correlation-based approach is used with this type of channel, a search strategy for the region of uncertainty of the random delay should be chosen. We consider a simplified situation, since our purpose is precisely the analysis of the possible search strategies. Comparison of a novel strategy based on the golden section and another efficient one shows that none of them is optimum from the point of view of the mean acquisition time. The golden section method, however, has a smaller complexity in the general case." } @INPROCEEDINGS{Aria0511:Unstable, AUTHOR="Peyman Arian", TITLE="Unstable {IIR-Like} Filter Blocks for Generating {Linear-Phase} {FIR} Filters: A Noise Analysis", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="The authors have recently proposed two alternative techniques for generating narrow transition band linear-phase FIR filters. The implementation of both designs requires a set of demultiplexers and IIR filters, which accounts for the efficiency of the designs. On the other hand, since the demultiplexers and the IIR filters go through an activation-deactivation cycle at different time slots, the noise analysis for the structure becomes extremely complex. This study aims to derive closed form formulae for the roundoff noise generated in the proposed structures." } @INPROCEEDINGS{Arie0511:FES, AUTHOR="Alejandro {Hernandez Arieta} and Hiroshi Yokoi and Tamio Arai and Wenwei Yu", TITLE="{FES} as Biofeedback for an {EMG} Controlled Prosthetic Hand", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="The importance of providing with biofeedback when interacting with man-machine interfaces has to be considered when developing new applications, in particular, with externally powered prosthetic devices. In this study we look to develop a tactile biofeedback system for this purpose using electrical stimulation. In this paper we study the ability of the human body to recognize different patterns of stimulation using two methods: surface and interferential current stimulation and their influence over the EMG acquisition process. The goal is to develop an appropriate feedback source to the human body to be used along with an EMG controlled prosthetic hand." } @INPROCEEDINGS{Arif0504:New, AUTHOR="Muhammad Arif and Noor Muhammad Sheikh and Asrar Sheikh", TITLE="New Deterministic Interleaver for turbo Codes", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="Turbo codes have received plenty of attention since their introduction. This is due to their impressive near Shannon limit error correcting. Interleaving is a key component of turbo codes. The design of interleaver is based on two major criteria: 1) the distance spectrum properties (weight distribution) of the code, and 2) the correlation between the soft output of the decoder corresponding to its parity bits and the information data sequence. The performance of turbo codes at low BER is mainly dominated by minimum effective free distance (dmin. The error floor, which usually appears in the region of bit error rate (BER) curve of turbo codes below 10-5, is the result of small dmin. The error floor can be lowered by increasing either interleaver size or dmin. The increase in interleaver size causes latency, whereas the increase in dmin can be achieved through appropriate design and choice of interleaver. It is well recognized that good spreading properties are desirable for achieving good distance properties (enlarged dmin). In this paper we present a new deterministic interleaver which is designed to exploit the advantages of both criteria simultaneously and also providing an interesting implementation advantage. The interleaver is defined by very simple rules and yet provides enhanced performance of turbo codes as compared to turbo codes that use long pseudorandom interleavers. A new and more effective definition of spread that is closely related to turbo codes was presented by Stewart. The spread measure is defined as the sum of separation distances between two write indexes i and j before and after interleaving. The theoretical maximum spread based on this definition is floor((2N)1/2), where N is length of interleave. Our design is based on the concept of trying to construct a deterministic interleaver that yields the maximum theoretical spread, defined by spread definition. The construction of new interleaver can be viewed in two steps. In first step we construct the interleaver using a very simple rule of increment k in modulo sense for each successive interleaved output, where k is size of increment. In our design, we choose k=S+1, where S is the maximum theoretical spread. For information data sequences i and j, I(i) and I(j) represent their interleaved locations in output vector. Mapping of index j\→I(j), where j=I(j) is a valid assignment for S-Random interleaver. Such assignment can degrade the performance of iterative decoding in turbo codes. The larger the displacement between j and I(j), the smaller the correlation between extrinsic information from one decoder to the input information data sequence at the input of the other decoder. In the second step, we try to maximize the minimum displacement distance d=| j-I(j) | by adding appropriate value of d for every index generation. This modification reduces the correlation and improves the suitability of iterative decoding. Simulation results are presented for an interleaver size of 128 and 200 data bits. The turbo code uses two identical, 4 state and 8 state rate ½ RSC codes in parallel. Unpunctured over all code rate is 1/3. S-Random interleaver is used as bench mark. Error floor occurs below EbN0=10-5 with S-Random interleaver and BER curve becomes flat thereafter. The BER curve with new deterministic interleaver shows at least equivalent performance in water fall region and significant improvement in error floor region. No error floor is observed till EbNo=10-7. The interleaver is suitable for applications using short length turbo codes. The generation of indexes is simple enough to accommodate on the fly generation of interleaver without storing the entire interleaver. This additional property makes the interleaver best suited for applications, which need parallel banks of turbo codes, with varying length of interleavers." } @INPROCEEDINGS{Arif0505:Modeling, AUTHOR="Md. Arifujjaman", TITLE="Modeling and Control of a Small Wind Turbine", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="This paper starts with a detailed survey of control methods commonly employed by commercially available small wind turbines. This detailed survey indicates that the most commonly used control method of small wind turbines is horizontal furling method. Such furling mechanism and resulting dynamics are described in the paper. Furling is used to control the aerodynamic power extraction from the wind. A dynamic model of a small wind turbine with furling dynamics is presented in this paper. Such small wind turbines are based on permanent magnet generators and their speed can be regulated using the load control. The extraction of maximum power output from such wind turbines is investigated using tip speed ratio control and hill-climbing control methods. The system is simulated in Matlab/Simulink to determine a suitable control strategy. Two dynamic controllers are designed and simulated. In the first method, a controller uses the wind speed and rotor speed information and controls the load in order to operate the wind turbine at the optimum tip speed ratio. The generator output is observed in varying wind condition as the furl angle increases and decreases. In the second method, a controller compares the output power of the turbine with the previous power and based on the comparison it controls the load. Using a hill-climbing algorithm the controller tries to extract the maximum power from the wind, while the generator output is observed as the furl angle increase or decreases. Finally, the output of these two controllers is compared and investigated to determine which controller leads to the best results." } @INPROCEEDINGS{Arif0511:Malay, AUTHOR="Ahmad {Kamarul Ariff} and Mohd Alwi and Sheikh Hussain {Sheikh Salleh}", TITLE="Malay Speaker Recognition System Based On Discrete {HMM}", BOOKTITLE="1st Conference on Computers, Communications, and Signal Processing", ADDRESS="Renaissance Kuala Lumpur Hotel, Kuala Lumpur, Malaysia", DAYS=14, MONTH=nov, YEAR=2005, ABSTRACT="This paper presents the design and implementation of Malay speaker recognition system using discrete hidden Markov model (HMM) as the classifier. A series of speaker recognition experiments was performed using 99 speakers (13 clients and 86 imposters) recording database consisting of isolated digit utterances. For a seven digit long sequence, 0.96\% EER was achieved." } @INPROCEEDINGS{Arik0509:Channel, AUTHOR="Erdal Arikan", TITLE="Channel combining and splitting for cutoff rate improvement", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="The cutoff rate R\_0(W) of a discrete memoryless channel (DMC) W is often used as a figure of merit, alongside the channel capacity C(W). Given a channel W consisting of two possibly correlated subchannels W\_1, W\_2, the capacity function always satisfies C(W\_1)+C(W\_2) <= C(W), while there are examples for which R\_0(W\_1)+R\_0(W\_2) > R\_0(W). This fact that cutoff rate can be ``created'' by channel splitting was noticed by Massey in his study of an optical modulation system modeled as a M'ary erasure channel. This paper demonstrates that similar gains in cutoff rate can be achieved for general DMC's by methods of channel combining and splitting. Relation of the proposed method to Pinsker's early work on cutoff rate improvement and to Imai-Hirakawa multi-level coding are also discussed." } @INPROCEEDINGS{Arim0509:Extension, AUTHOR="Mitsuharu Arimura and Hiroshi Nagaoka", TITLE="An Extension of Asymptotically Sufficient Statistic Method for Pointwise Strong Universality", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="In the previous work in Proc. ISIT2003 and Proc. ISITA2004, we have investigated some relationships between sufficient statistic and weakly universal lossless source coding, and proposed {\em asymptotically sufficient statistic method} to evaluate the pointwise redundancy of source codes. This method is an attempt to understand the universality of general lossless source codes from a simple and unified viewpoint. In this paper, we present a new theorem which enables our method to show the pointwise strong universality of lossless source codes. As an example of the theorem, we prove the pointwise strong universality of the original Lynch-Davisson code and conditional Lynch-Davisson code for the class of stationary memoryless and Markov sources, respectively. Moreover, it is shown that this method can be applied to the class of finite state sources. We prove that a blockwise Lynch-Davisson code is pointwise strongly universal for this class. From the viewpoint of our method, all of these algorithms can be seen as examples of a two-step source code using a kind of asymptotically sufficient statistic. The result of this paper gives a unified viewpoint for the universality of context-based algorithms and block-based algorithms, which are typical two types of universal lossless source coding algorithms." } @INPROCEEDINGS{Arim0511:FEC, AUTHOR="Satoshi Arima and Takuji Tachibana and Shoji Kasahara", TITLE="{FEC-Based} Burst Loss Recovery for {Multiple-Bursts} Transmission in Optical Burst Switching Networks", BOOKTITLE="Globecom 2005 Photonic Technologies for Communications", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="Currently, Grid computing and CD/DVD delivery are considered as applications in OBS networks. For these applications, multiple bursts are required to be transmitted simultaneously to any node in contrast with the conventional burst transmission. Moreover, the reliable transmission has to be provided for the multiple bursts. In this paper, we propose a consecutive burst transmission with burst loss recovery based on Forward Error Correction (FEC) for the multiplebursts transmission. In the proposed method, redundant data is generated from multiple bursts with FEC, and a redundant burst is assembled with the redundant data. Then, the multiple bursts and the redundant burst are transmitted consecutively. If a burst among the bursts is lost at some intermediate node, the lost burst is recovered with the redundant burst at the destination. We evaluate by simulation the proposed method in a uni-directional ring network and compare the performance of the proposed method with the extra-offset time scheme. Numerical examples show that the proposed method can provide a more reliable transmission than the extra-offset time scheme for the OBS network where the burst size and the maximum number of hops are large." } @INPROCEEDINGS{Arip0511:Downlink, AUTHOR="Mahamod Ismail and Norazizah {Mohd Aripin} and Norhayati Ahmad and Muhammad Yusof Ibrahim", TITLE="Downlink Soft Handover Mechanism Performance in {WCDMA} System", BOOKTITLE="Tencon '05 - IEEE Region 10 Conference", ADDRESS="Melbourne, Australia", DAYS=21, MONTH=nov, YEAR=2005, ABSTRACT="An in depth study of the soft handover effects on the downlink direction of WCDMA network is carried out. The link level study begins with the downlink interference analysis and power allocations for each downlink dedicated channels. Downlink soft handover gain is used in the system level simulation as a main parameter to evaluate the effects of cell selection and power control mechanisms on the downlink soft handover performance. Simulation shown that by using 2-way soft handover mechanism, the required dedicated transmission power up can be reduced up to 3 dB. Besides that, the cell selection scheme based on distance and Ec/I0 value gives better SHO gain (1.3 dB) to the system with SHO overhead equals to 30\%. Simulation also has shown that the system can benefit from the soft handover process at 20\% to 30\% of the SHO overhead. However, power control mechanism does not give significant impact to the SHO gain." } @INPROCEEDINGS{Ariy0505:List, AUTHOR="Sirikiat Ariyavisitakul and Manoneet Singh", TITLE="A List Layered {Space-Time} Approach for {MIMO} Detection", BOOKTITLE="ICC 2005 Wireless Communications", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="This paper describes a layered space-time (LST) approach for multiple-input, multiple-output (MIMO) channels where list decisions of each data substream are used to subtract interference when detecting the next data substream. We study this approach in the context of the IEEE 802.11 standard using orthogonal frequency-division multiplexing (OFDM) and bit-interleaved coded modulation of each subcarrier. We show that ideal list LST with increased list size can potentially approach the MIMO Shannon bound, but performance of real implementation based on a reduced-complexity demapper is limited by competing Euclidean distances common in any reduced-state maximum likelihood detection." } @INPROCEEDINGS{Arkh0505:Dynamic, AUTHOR="Alexander Arkhipov and Ronald Raulefs and Michael Schnell", TITLE="Advantages of Superimposed Packets Allocation for {OFDM-CDM}", BOOKTITLE="Vehicular Technology Conference Spring 2005 System Architectures for Beyond 3G", DAYS=29, MONTH=may, YEAR=2005, ABSTRACT="In this paper, superimposed packets allocation for orthogonal frequency-division multiplexing code-division multiplexing (OFDM-CDM) is presented. An iterative algorithm, which is a combination of parallel interference cancellation (PIC) and automatic repeat request (ARQ) based on soft value combining (SVC) is proposed and its performance studied and compared with other existing ARQ schemes. In the proposed algorithm, reliability information of erroneously received copies of the same data packet is exploited to improve the quality of interference cancellation. As a result, the proposed algorithm outperforms conventional ARQ based on a SVC as well as ARQ based on maximum ratio combining (MRC)." } @INPROCEEDINGS{Arkh0509:Combination, AUTHOR="Alexander Arkhipov and Ronald Raulefs and Michael Schnell", TITLE="Combination of {H-ARQ} and {Multi-User} Detection for {OFDMA-CDM}", BOOKTITLE="5th Int'l. Workshop on Multi-Carrier Spread Spectrum", ADDRESS="Oberpfaffenhofen, Germany", DAYS=14, MONTH=sep, YEAR=2005, ABSTRACT="\—In this paper, superimposed packet allocation for orthogonal frequency-division multiple-access code-division multiplexing (OFDMA-CDM) is presented, where each transmitted packet is associated with one spreading code. An iterative algorithm which is a combination of iterative (turbo) multiuser detection and hybrid automatic repeat request (H-ARQ) based on soft value combining (SVC) is proposed, and its performance is studied and compared with other existing H-ARQ schemes. The proposed algorithm exploits the reliability information of erroneously received copies of the same data packet to improve the performance of interference cancellation. The interference of correctly received packets is ideally reconstructed and subtracted; thus, the overall system performance improves iteratively. As a result, the proposed algorithm outperforms conventional H-ARQ based on SVC as well as H-ARQ based on maximum ratio combining (MRC)." } @INPROCEEDINGS{Arme0507:Transmission, AUTHOR="Sergio Armenia and Laura Galluccio and Alessandro Leonardi and Sergio Palazzo", TITLE="Transmission of {VoIP} Traffic in Multihop Ad Hoc {IEEE} 802.11b Networks: Experimental Results", BOOKTITLE="Wireless Internet Conference 2005", ADDRESS="Budapest, HUNGARY", DAYS=17, MONTH=jul, YEAR=2005, ABSTRACT="In the last decade numerous studies on the transmission of VoIP traffic over wireless networks have been carried out. However, only few works have addressed the topic of supporting real time audio applications over multihop ad hoc networks neither using simulation nor testbeds. In this paper the results of the implementation of a real VoIP testbed over a multihop IEEE 802.11b ad hoc network are presented. More specifically, the quality of the voice transmission is measured through different performance metrics such as the PESQ-MOS parameter, the delay and the packet loss. Moreover, the quality of the real-time audio transmission has been evaluated when two different multihop routing protocols such as AODV and OLSR are used." } @INPROCEEDINGS{Armu0504:Profiling, AUTHOR="Ivan Armuelles and Jorge {López de Vergara} and Tomas {Robles Valladares} and David Fernandez", TITLE="Profiling for Mobility Context Management and Transport Service Provision in {4G} Networks", BOOKTITLE="11th European Wireless 2005", ADDRESS="Nicosia, Cyprus", DAYS=10, MONTH=apr, YEAR=2005, ABSTRACT="Currently, mobile service provision is facing important advancements towards more flexible business models and fresh Internet-like services, with the internetworking of several complementary access technologies using the Internet Protocol (IP) as a mean of integration. The result of such integration, also known as 4th Generation Networks, will require the provision of a persistent transport service of for users session flows and transactions. In this paper we present the conceptual high level description of a context-based management distributed service and profiling system in order to provide this persistent transport for mobile users data applications in a heterogeneous environment of IP-based network." } @INPROCEEDINGS{Arno0504:Comparison, AUTHOR="Matthias Arnold and Oliver Litschke and Dirk Manteuffel", TITLE="A comparison of three methods to determine the efficiency of terminal antennas", BOOKTITLE="Loughborough Antennas and Propagation Conference 2005", ADDRESS="Burleigh Court Conference Centre", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="One of the most challenging problems in handset antenna measurements is the determination of the efficiency. In this paper a comparison between the Wheeler-Cap method, a 3D-measurement setup and simulated/calculated efficiency results (EmpireTM[3]) is presented." } @INPROCEEDINGS{Aror0503:UGSP, AUTHOR="Neelima Arora and R. k. Shyamasundar", TITLE="A protocol for Secure Communication in {Peer-to-Peer} System", BOOKTITLE="IEEE Wireless Communications \& Networking Conference", ADDRESS="New Orleans", DAYS=13, MONTH=mar, YEAR=2005, ABSTRACT="A wireless ad-hoc network is a collection of mobile nodes with no fixed infrastructure. Security in such networks poses serious challenges due to (i) the network connectivity could be intermittent and hence on-line authentication is not guaranteed, and (ii) susceptible to wide range of attacks due to broadcast communication. Even though protocols for secure communication exist in ad-hoc networks, most assume a pre-distributed security parameters. In this paper, we propose a secure key establishment protocol, called UGSP, for wireless ad-hoc networks using tamper-proof hardware. UGSP results in creating a secure communication channel between two nodes without any third party involvement and hence is suitable for ad-hoc networks. UGSP is robust to man-in-the-middle attack, passive eavesdropping, active impersonation attacks ensuring source authentication, data confidentiality and data integrity for communication. The system is amenable to dynamic addition of new members. We provide a comparative evaluation of UGSP with other approaches and show that UGSP is scalable and cost-effective." } @TECHREPORT{Arro0503:Effects, AUTHOR="David Arrowsmith and Mario Bernardo and Francesco Sorrentino", TITLE="Effects of variations of load distribution on network performance", TYPE="arXiv report", INSTITUTION="arXiv", NUMBER="cs.NI/0503090", MONTH=mar, YEAR=2005, KEYWORDS="Networking and Internet Architecture", ABSTRACT="This paper is concerned with the characterization of the relationship between topology and traffic dynamics. We use a model of network generation that allows the transition from random to scale free networks. Specifically, we consider three different topological types of network: random, scale-free with \gamma = 3, scale-free with \gamma = 2. By using a novel LRD traffic generator, we observe best performance, in terms of transmission rates and delivered packets, in the case of random networks. We show that, even if scale-free networks are characterized by shorter characteristic-path- length (the lower the exponent, the lower the path-length), they show worst performances in terms of communication. We conjecture this could be explained in terms of changes in the load distribution, defined here as the number of shortest paths going through a given vertex. In fact, that distribu- tion is characterized by (i) a decreasing mean (ii) an increas- ing standard deviation, as the networks becomes scale-free (especially scale-free networks with low exponents). The use of a degree-independent server also discriminates against a scale-free structure. As a result, since the model is un- controlled, most packets will go through the same vertices, favoring the onset of congestion.", URL="http://arxiv.org/abs/cs/0503090" } @INPROCEEDINGS{Arta0511:Multi, AUTHOR="Sertac Artan and H. Jonathan Chao", TITLE="Multi-packet Signature Detection using Prefix Bloom Filters", BOOKTITLE="Globecom 2005 Computer \& Network Security", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="It is now a fact that manual defenses against worm epidemics are not practical. Recently, various automatic worm identification methods are proposed to be deployed at high-speed network nodes to respond in time to fast infection rates of worms. Unfortunately, these methods can easily be evaded by fragmentation of the worm packets. The straightforward defragmentation method is not applicable for these high-speed nodes, due to its high storage (memory) requirement. In this paper, this problem, namely the multi-packet signature detection problem is addressed using a defragmentation-free, space-efficient solution. A new data structure - Prefix Bloom Filters - along with a new heuristic, called the chain heuristic is proposed to significantly reduce the storage requirement of the problem, so that multi-packet signature detection become feasible for high-speed network nodes." } @INPROCEEDINGS{Arte0504:Applicability, AUTHOR="Wayne Arter", TITLE="Applicability of the {CLASP} Software for Installed Antenna Performance", BOOKTITLE="Loughborough Antennas and Propagation Conference 2005", ADDRESS="Burleigh Court Conference Centre", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="The CLASP suite of electromagnetic design tools is taken as the representative of the class of MoM (Method-of-Moments) software, and is compared with typical FDTD (Finite-Difference Time-Domain) codes with the same function. The emphasis of the study is on installed antenna performance, but includes discussion of radar cross-section (RCS) work. Although FDTD codes have advanced significantly since CLASP was conceived in the early 1990s, it is shown that MoM, specifically CLASP, continues to be the method of choice for many design problems." } @INPROCEEDINGS{Arum0505:Turbo, AUTHOR="Nallanathan Arumugam", TITLE="Turbo Differential {Space-Time} Block Codes with Iterative Demodulation and Decoding", BOOKTITLE="ICC 2005 Signal Processing for Communications", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="The advantage of differential space-time block code (DSTBC) over conventional space-time block code (STBC) is that the former does not require perfect channel state information (CSI). The trade-off is a penalty of approximately 3 dB in performance. Due to the recursive structure of DSTBC, iterative demodulation and decoding can be performed on a system of concatenated component DSTBC encoders. This paper proposes the parallel concatenation of two DSTBC blocks separated by an interleaver. It is shown that the 3 dB penalty can be sufficiently recovered within a few iterations." } @INPROCEEDINGS{Arya0505:Encodings, AUTHOR="Vijay Arya and Thierry Turletti and Shivkumar Kalyanaraman", TITLE="Encodings of Multicast Trees", BOOKTITLE="NETWORKING 2005", ADDRESS="Waterloo, Ontario, Canada", DAYS=2, MONTH=may, YEAR=2005, ABSTRACT="In this paper, we present efficient ways of encoding multicast trees. Multicast tree encodings providing a convenient way of performing stateless and explicit multicast routing in networks and overlays. We show the correspondence of multicast trees to theoretical tree data structures and give lower bounds on the number of bits needed to represent multicast trees. Our encodings can be used to represent multicast trees using both both node identifiers and link indexes and are based on balanced parenthesis representation of tree data structures. These encodings are almost space optimal and can be read and processed efficiently. We evaluate the length of these encodings on multicast trees trees in generated and real topologies." } @INPROCEEDINGS{Asai0506:Recognition, AUTHOR="Takahiro Asai and Anass Benjebbour and Hitoshi Yoshino", TITLE="Recognition of {CDMA} Signals with Orthogonal Codes using Cyclostationarity", BOOKTITLE="The Sixth IEEE International Workshop on Signal Processing Advances in Wireless Communications", ADDRESS="The Italian Academy for Advance Studies in America at Columbia University, New Y", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="The concept of cyclostationarity can be used for recognition, extraction, and synchronization. A signal exhibits cyclostationarity if its cyclic autocorrelation function (CAF) is non-zero for a non-zero cycle frequency. The CAF and cycle frequencies differ from one signal to another depending on their characteristics such as carrier frequency and baud rate. Therefore, the property of cyclostationarity exhibited by modulated signals can be exploited for recognition, extraction, and synchronization. In this paper, we employ cyclostationarity for the recognition of CDMA signals where orthogonal spreading codes together with chip rate sampling are used. First, we derive an explicit formula for the CAF of such CDMA signals, then demonstrate how the cyclostationarity associated with spreading decreases as the number of multiplexed codes increases. This cyclostationarity is shown to completely disappear if a scrambling code is used together with the spreading code. Furthermore, two cases are considered for enhancing the detection probability: the case of antenna diversity and the case when multiple CDMA signals are allocated to different bandwidths. Finally, computer simulations show that the detection probability of a CDMA signal can be improved in both cases." } @INPROCEEDINGS{Asch0504:Traffic, AUTHOR="Nils Aschenbruck and Matthias Frank and Peter Martini and Jens Toelle", TITLE="Traffic Measurement and Statistical Analysis in a Disaster Area Scenario", BOOKTITLE="1st workshop on Wireless Network Measurements", ADDRESS="Trento (Italy)", DAYS=3, MONTH=apr, YEAR=2005, ABSTRACT="Disaster areas are a typical usage scenario for mobile wireless communication systems (e.g. ad-hoc networks). Performance evaluation in mobile wireless communication systems is mainly done using simulation. Simulation results strongly depend on the traffic models used. Today, the traffic mainly used in disaster areas is voice traffic. In this paper, we present measurements of voice traffic done in a disaster area maneuver. Based on these measurements, we perform a statistical analysis of channel holding and interarrival times. We show that the traffic in disaster area scenarios has characteristics different from public mobile telephony systems. Thus, when simulating disaster area networks, different traffic characteristics should be assumed. With the results presented in this paper, it is possible to reach a realistic traffic for disaster area scenarios." } @INPROCEEDINGS{Asfo0506:Reliable, AUTHOR="Taghrid Asfour", TITLE="Reliable multicast over satellite networks", BOOKTITLE="10th IEEE Symposium on Computers and Communications", ADDRESS="La Manga del Mar Menor, Cartagena, SPAIN", DAYS=27, MONTH=jun, YEAR=2005, ABSTRACT="In this paper we address the issue of reliable multicast transport over satellite networks. The considered satellite system is a LEO constellation which has been simulated using the network simulator NS in order to analyze the delay characteristics of the system. To enable reliable multicast over satellite networks we propose to use Sat-RMTP. We propose as well to integrate forward error correction (FEC) into Sat-RMTP in order to increase its performance and to reduce the need of retransmission requests. Unfortunately the simulation results show that FEC is unable to fulfill its role in error recovery due to the fact that errors over satellite networks are temporally very bursty. To overcome this problem we propose a new mechanism that we call ``error distribution mechanism''. This mechanism intends to make loss appear more distributed at the receiver side. To achieve this objective, the sender has to send data out of order so that the probability that many consecutive packets in the same FEC block will be lost simultaneously decreases." } @INPROCEEDINGS{Asge0505:Vertex, AUTHOR="Eyjolfur Asgeirsson and Cliff Stein", TITLE="Vertex cover approximations: Experiments and observations", BOOKTITLE="4th International Workshop on Efficient and Experimental Algorithms", ADDRESS="Santorini Island, Greece", DAYS=10, MONTH=may, YEAR=2005, ABSTRACT="The vertex cover problem is a classic NP-complete problem for which the best worst-case approximation ratio is roughly 2. In this paper, we use a collection of simple heuristics, each of which guarantees an approximation ratio of 3/2, to find approximate vertex covers for a large collection of test graphs from various sources. We explain these heuristics and explore the interaction between them. These heuristics are extremely fast and even though they, by themselves are not guaranteed to find a vertex cover, we manage to find a 3/2-approximate vertex cover for every single graph in our large collection of test examples." } @INPROCEEDINGS{Asha0511:Performance, AUTHOR="Omar Ashagi and Antonio Ruzzelli and Sean Murphy and Liam Murphy and John Murphy", TITLE="Performance Modelling of a Distributed Approach to Interference Mitigation in {License-Exempt} {IEEE} {802.16} Systems", BOOKTITLE="First IEEE International Symposium on New Frontiers in Dynamic Spectrum Access Networks", ADDRESS="Baltimore, MD USA", DAYS=8, MONTH=nov, YEAR=2005, ABSTRACT="Three approaches to modelling a distributed approach to interference mitigation in 802.16 License-exempt (LE) systems, which was published in previous work, are described. Rather than assuming the system is fully distributed, these approaches assume that the system can be co-ordinated and that full system knowledge is known at some point. Hence, good scheduling approaches can be derived for the overall system which result in minimal interference. The three approaches differ in the way they arrive at a schedule for the system. In the interference-free (IF) approach, no interference is permitted at any node in the system; in the CI-T and CI-F approaches, controlled interference is permitted, but interference only occurs at nodes that do not benefit from receiving the current transmission. The CI-T and CI-F approaches differ in their objective: the CI-T attempts to maximise throughput, while the CI-F approach attempts to maximise fairness between Base Stations. The performance of the three approaches is compared with that of the distributed approach. The results show that the CI-F and CI-T schemes result in much better overall performance than either the IF scheme or the distributed scheme. Further, they result in much greater levels of BS activity. Despite being very conservative, even the IF scheme performs better than the distributed scheme in terms of throughput. This can be attributed to the fact that the distributed scheme suffers from collisions. It seems there is much scope to improve the distributed scheme." } @INPROCEEDINGS{Ashi0504:Video, AUTHOR="Majdi Ashibani", TITLE="Video Delivery over Broadband Mobile Networks", BOOKTITLE="International Symposium on Wireless Systems and Networks", ADDRESS="KFUPM, Dhahran", DAYS=26, MONTH=dec, YEAR=2005, ABSTRACT="Video Delivery over Broadband Mobile Networks Majdi Ashibani and Fathi Ben Shatwan mashibani(at)yahoo.co.uk \& shatwan(at)hotmail.com Higher Institute of Industry P. Box 18449, Misurata, Libya (Extended Summary) Video streaming over wireless networks has undergone enormous development recently due to the continuing growth in wireless communication, especially since the emergence of 3G wireless networks. The new generations of wireless networks pose many challenges, including supporting quality of service (QoS) over wireless communication links. This is due to the time-varying characteristics of wireless channel. However, future broadband mobile networks are expected to support applications with diverse traffic characteristics and performance requirements such as multimedia applications. The limiting factor of wireless networking is the distance versus bandwidth issue, because the further the mobile host is from the base station, the slower the bit rates transfer. Although wireless LAN connection has the possibility of 11Mbps and over, this can be as low as 1Mbps as the distance increases.. Thus, from the system point of view, it is important to allocate available wireless network resources dynamically. On the other hand, with regard to video compression, it is necessary to employ scalable multilayer video compression in wireless environments. It has been shown that scalable multilayer video is suited to handle the variability of network conditions gracefullyý. In general, compressed video sequences are generally highly bursty in nature, i.e., various amounts of data might be generated during varying time intervals. In this case, the amount of aggregate incoming traffic is greater than the outgoing wireless link speed and packets have to be buffered. If this situation persists, packets will be dropped due to buffer overflows, which will in turn cause degradation of an applications QoS. Thus, to guarantee the transmission of compressed video with consistent perceptual quality, the maximum amount of bandwidth for encoded data has to be allocated. Due to the above problems, a more flexible and efficient bandwidth allocation scheme is needed. Therefore, this paper which is a part of ongoing work to come up with a more robust scheme that is capable of rapidly adapting to changes in network conditions. This scheme focuses on the wireless part of the network, providing high quality video service and better network resource utilization. The proposed scheme is applicable to wireless and mobile networking environments due to the existence of large scale mobility requirements, limited radio resources, and fluctuating network conditions. The proposed scheme is an attempt to develop a QoS-aware algorithm that is required for the new generations of mobile and wireless networks, such as 3G and 4G networks. The QoS-aware adaptation scheme allows applications to delegate responsibly by augmenting or reducing the perceptual quality of video flows to the transport system. The augmentation or reduction is performed when network resource availability increases or decreases respectively. This strategy is basically a QoS-controlled bandwidth management that uses the notation of an adaptive network service. A number of Differentiated services IP connections are provided for the multilayed compressed video streams, with a hard guarantee for the base layer and soft guarantee for the enhancement layers. In UMTS (3G) networks, a number of base stations are connected to Radio Network Controller (RNC), where much of the intelligence of the mobile system exists. Therefore, the RNC manages all advanced radio related functions; handover, radio channel assignments, collection of cell configuration data, and QoS issues. Advanced load balancing and admission control functionality also exists in the RNC. Our proposed scheme should be implemented at these strategic points of the network (RNC). The active transport system uses the notation of mobile transport objects, which can be dispatched on demand to strategic points in the network (e.g. RNCs) to provide value-added QoS support when and where needed." } @INPROCEEDINGS{Ashi0509:Decoding, AUTHOR="Alexei Ashikhmin and Vitaly Skachek", TITLE="Decoding of Expander Codes at Rates Close to Capacity", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="The concatenation of nearly-MDS expander codes of Roth and Skachek, ``On Nearly-MDS Expander Codes,'' Proc. IEEE ISIT'04, with `typical' LDPC codes is investigated. It is shown that for the rates $R=(1-\varepsilon)C$ ($C$ is the capacity of the binary symmetric channel (BSC)), under certain condition on the parameters of LDPC codes, these concatenated codes have decoding time linear in their length and polynomial in $1/\varepsilon$, and the decoding error probability decays exponentially. These codes are compared to the recently presented codes of Barg and Z\'emor, ``Error Exponents of Expander Codes,'' IEEE Trans. Inform. Theory, 2002, and ``Concatenated Codes: Serial and Parallel,'' IEEE Trans. Inform. Theory, 2005. It is shown that the latter families can not be tuned to have all the aforementioned properties." } @INPROCEEDINGS{Ashi0509:Space, AUTHOR="Alexei Ashikhmin and A. Robert Calderbank", TITLE="{Space-Time} {Reed-Muller} Codes for Noncoherent {MIMO} Transmission", BOOKTITLE="2005 IEEE International Symposium on Information Theory", ADDRESS="Adelaide Convention Centre, Adelaide, Australia", DAYS=4, MONTH=sep, YEAR=2005, ABSTRACT="We present a family of Space-Time codes for the noncoherent MIMO channel. The codes are constructed via functions that can be considered as a generalization of boolean functions to commuting projection operators which arise in the theory of quantum stabilizer codes. These space-time codes are strongly related to standard binary Reed-Muller codes. In particular, they can be decoded by adapting a decoding algorithm for Reed-Muller codes. We show that the first subclass of codes from this family, which we view as the first order space-time Reed-Muller codes, allow transmission with rates close to the MIMO noncoherent channel capacity in the low signal to noise ratio (SNR) regime." } @INPROCEEDINGS{Asho0505:Performance, AUTHOR="Mohamed Ashour and Tho Le-Ngoc", TITLE="Performance of Weighted Fair Queuing Systems with Long Range Dependent Traffic Inputs", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="This paper provides an analytical technique for estimating the queue length distributions for a weighted fair queue (WFQ) system fed with Long Range Dependent (LRD) traffic input. The analysis considers the coupling between the queues of the WFQ system due to the dependency of the queue length on weights and the input traffic of other queues. It is also applicable to both LRD and Short Range Dependent (SRD) traffic sources. With aggregate LRD traffic streams represented by Multi-Scale Wavelet Models (MWM), the analysis starts by modeling each queue of a WFQ system as an MWM/D/1 queue and Multi-Scale Queuing (MSQ) is used to estimate the queue length distribution. Each queue unused capacity is evaluated and an extension of our previous work on priority queuing of LRD traffic is used to provide an MWM model for the service rate of each queue and decompose the WFQ queues into MWM/MWM/1 queues. Subsequently, this MWM/MWM/1 decomposition is used to examine the queue length distribution. The accuracy of the proposed analytical technique is examined by comparing queue survivor functions obtained analytically to those directly measured from event driven simulations for various traffic conditions and WFQ weight configurations. The analysis shows the effect of both weight variation and traffic self-similarity on the queue length distribution of each queue. Analytical and simulation results show that the proposed analytical technique can provide an accurate estimation of queue length distribution, and can be useful in optimal choices of WFQ weights." } @INPROCEEDINGS{Asho0508:Delay, AUTHOR="Mohamed Ashour and Tho Le-Ngoc", TITLE="Delay Satisfaction {End-to-End} Priority Assignment and Routing in {Multi-Class} Priority Networks", BOOKTITLE="The Second International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks (QShine)", DAYS=22, MONTH=aug, YEAR=2005, ABSTRACT="This paper develops QoS-based routing and priority class assignment algorithms using the end-to-end delay satisfaction balancing concept. The paper extends the nonlinear convex formulation of single-class network to include the decencies introduced by the priority queue and shows that multi-class case the objective function is only convex within specific regions. A centralized offline computation of route configurations and end-to-end priority assignment is presented. The approach uses that a gradient-based solution in the convex region and a heuristic to overcome the discontinuity. The formulation is also used to provide an on-line approximation of the centralized offline computation, where vector routing tables can be used to set up paths for arriving calls. Performance of the proposed schemes is evaluated and compared with that of single-class routing and fixed-priority assignment. Results show that using a delay satisfaction balancing based objective function for both the choice of routes and the assignment of priority classes enables the network to accommodate more users of varying end-to-end delay requirements." } @INPROCEEDINGS{Asho0511:End, AUTHOR="Mohamed Ashour and Tho Le-Ngoc", TITLE="{End-to-End} Delay Satisfaction Balancing Routing", BOOKTITLE="Globecom 2005 Advances for Networks \& Internet", ADDRESS="St. Louis", DAYS=28, MONTH=nov, YEAR=2005, ABSTRACT="This paper develops QoS-based routing algorithms using the end-to-end delay satisfaction balancing concept. The approach is intended for network that do not support per path reservation such as DiffServ networks. Nonlinear convex formulation of the problem and a gradient-based solution is are presented for off-line computation of optimal route configuration. The formulation is also used to provide an on-line approximation of the optimization problem where vector routing tables can be used to setup paths for arriving end calls. Performance of the proposed schemes is evaluated and compared with that of minimum-delay, minimum-hop, and min-interference routing algorithms. Results show that using a delay satisfaction balancing based objective function enables the network to accommodate more users of varying end-to-end delay requirements." } @INPROCEEDINGS{Ashr0505:Automatic, AUTHOR="Muhammad Ashraf", TITLE="Automatic Tuning of Digital {PID} Controllers for {MIMO} Processes", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="Tuning of controllers is one of the most basic functions of control engineers. There are always loops in the plant that are in need of tuning The auto tuned PID Controllers are designed for use on applications where large load changes are expected or the need for extreme accuracy and fast response time exists The algorithm presented in this paper can be used for the tuning controller to obtain its parameters with a minimum number of process moves. It requires continuous analysis of variation in few parameters, and let the program to do the plant test and calculate the controller parameters to adjust and optimise the variables for the best performance. The algorithm developed needs less time as compared to a normal step-test for continuous tuning of the PID." } @INPROCEEDINGS{Asif0509:Parallel, AUTHOR="Saad Asif", TITLE="Interference Cancellation Technique for cdma2000 Handsets", BOOKTITLE="VTC'F05 Wireless Personal Communication Systems", DAYS=25, MONTH=sep, YEAR=2005, ABSTRACT="Abstract The recent forecasts on wireless applications and services are challenging North American operators to enhance the capacity of their networks. Keeping this challenge in mind, Sprint has devoted considerable resources to explore techniques that could improve the performance of the downlink. One such technique is Interference Cancellation (IC) which can be incorporated in mobile terminals to improve the performance of the downlink. The technology is discussed in context of downlink (base station to mobile) since commercial CDMA systems are mainly downlink and interference limited. Two of the major sources of interference are inter and intra sector interference, which IC technique works to resolve. Sprint had conducted lab and field testing with third party prototype handsets which were IC enabled. The testing helped to understand the performance of this technique and its impact on the voice capacity of cdma2000 systems. The testing showed that IC capable handsets would reduce the forward traffic channel power by up to 2.5 dB. This reduction in power would increase the voice capacity of the cdma2000 systems." } @INPROCEEDINGS{Asla0502:NPP, AUTHOR="Faisal Aslam and Saqib Raza and Fahad Dogar and Zartash Uzmi", TITLE="{NPP:} A Facility based Computation Framework for Restoration Routing using Aggregate Usage Information", BOOKTITLE="3rd International Workshop on QoS in Multiservice IP Networks", ADDRESS="Catania (Italy)", DAYS=2, MONTH=feb, YEAR=2005, ABSTRACT="We present NPP---a new framework for online routing of bandwidth guaranteed paths with local restoration. Our framework relies on the propagation of aggregate link usage information through routing protocols [2, 10]. The key advantage of this framework is that it delivers the bandwidth sharing performance achieved by propagating complete per path link usage information [10], while incurring the significantly reduced routing protocol overhead. We specify precise implementation models for the restoration routing frameworks presented in [1] and [2] and compare their traffic placement characteristics with those of NPP. Simulation results show that NPP performs significantly better in terms of number of LSPs accepted and total bandwidth placed on the network. For 1000 randomly selected LSP requests on a 20-node homogenous ISP network [9], NPP accepts 775 requests on average compared to 573 requests accepted by the framework of [2] and 693 requests accepted by the framework of [1]. Experiments with different sets of LSP requests and on other networks indicate that NPP results in similar performance gains." } @INPROCEEDINGS{Asor0507:Packet, AUTHOR="Rafael Asorey-Cacheda and Francisco Castano and Maria Crespo and Luca Caviglione and Franco Davoli", TITLE="A packet sniffing and synchronization technique to boost {P2P} satellite networks", BOOKTITLE="Hot Topics in Peer-to-Peer Systems", ADDRESS="San Diego, CA, USA", DAYS=21, MONTH=jul, YEAR=2005, ABSTRACT="In this paper we propose a collaborative technique called P2P-SatBoost to improve the performance of P2P (Peer-to-Peer) protocols over satellite networks, and we evaluate it from the perspective of user satisfaction. Highly asymmetric satellite IP connections (satellite downlink and POTS uplink, for example) may be the only reasonably fast access possibility for users in remote regions, specially in the third world. Our technique exploits user ubiquitous access (within a given satellite footprint) and it relies on packet sniffing and any synchronization protocol between peers. We provide a brief description of the packet sniffing procedure and propose a synchronization protocol. The simulation results indicate that joint packet sniffing and synchronization can substantially speed up P2P downloads." } @INPROCEEDINGS{Asor0509:P2P, AUTHOR="Rafael Asorey-Cacheda and Francisco Castano and Maria Crespo and Luca Caviglione and Franco Davoli", TITLE="{P2P} and Satellite Networks: a master-worker synchronization architecture to improve performance", BOOKTITLE="International Workshop on Satellite and Space Communications 2005", ADDRESS="Siena, Italy", DAYS=8, MONTH=sep, YEAR=2005, ABSTRACT="In the last years, the peer-to-peer (P2P) paradigm has become very important. One of the reasons for this is that it replaces the client-server paradigm, thus eliminating transactions intermediaries. Another reason is that broadband is nowadays widespread, allowing the development of P2P services. P2P is being used for many different applications: GRID computing, telephony, mail, file sharing, etc. However, due to their popularity, P2P is mainly associated to file-sharing applications. On the other hand, satellite communication systems are widely adopted to offer broadband Internet access to home users and enterprises, specially in places where terrestrial access is unfeasible. Due to the special characteristics of satellite networks, P2P protocols are quite inefficient in them if compared to other technologies. In this paper, we describe P2P and how it operates on satellite networks. We focus on the problems that arise from the usage of P2P protocols over TCP connections and how they limit overall system performance. Finally, we propose a innovative technique based on the master-worker paradigm for the synchronization proccess and combined with packet sniffing in the satellite channel." } @INPROCEEDINGS{Asra0506:Performance, AUTHOR="Daniel Asraf and Harry Leib", TITLE="Performance Bounds for Quadratic {Multi-Ratio} Optimization in Communication Systems", BOOKTITLE="Canadian Workshop on Information Theory", ADDRESS="Montreal, Quebec", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="In this paper, upper bounds are derived for a particular nonlinear and nonconvex multi-objective optimization problem, specifically a so-called quadratic multi-ratio fractional program. This is a generalized formulation of many optimization problems appearing in applications such as transmit beamforming in a multiuser environment and equalizer design in a multicarrier system. Two scalarization techniques are considered namely the weighted sum and Nash arbitration (objective product), which result in conventional scalar optimization problems that are nonconvex and highly nonlinear. These problems are known to be difficult to treat with only limited results available, both in terms of analytical studies and numerical solution methods. Generally, global optimization techniques are required, which come at the cost of increased hardware and algorithmic complexity. Many methods for global optimization require bounds on the optimal value of the nonlinear nonconvex objective function, which is the motivation for deriving the upper bounds presented in this paper. The tightness of these bounds are evaluated by numerical simulations, which are set up in the context of a transmit beamforming example." } @INPROCEEDINGS{Assa0509:Scheduling, AUTHOR="Mohamad Assaad and Djamal Zeghlache", TITLE="Scheduling Study in {HSDPA} System", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT={This paper focuses on the study of scheduling techniques in HSDPA system. In this context, we propose to use a Score Based (SB) scheduling algorithm in HSDPA. This algorithm is compared to another scheduling algorithm, called Proportional Fair (PF), widely used and studied in the literature. To make this comparison, an analytical model allowing to evaluate the cell capacity and the user bit rate is proposed. The radio channel is assumed to be a dense multipath frequency selective channel with uncorrelated signal envelope following a Rayleigh distribution and Wide-sense Stationary Uncorrelated Scattering (WSSUS). Results show that SB seems to be a better trade-off between {"}fairness{"} and {"}efficiency{"} than PF.} } @INPROCEEDINGS{Assi0505:Benefits, AUTHOR="Chadi Assi and Wei Huo and Abdallah Shami and Nasir Ghani", TITLE="On The Benefits of Lightpath {Re-Provisioning} in Optical Mesh Networks", BOOKTITLE="ICC 2005 Optical Networking", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="A key means for improving service availability in optical networks is the ability to recover from multiple near-simultaneous failures. To date, most studies have focused on improving survivability for single failure events either via proactive or reactive mechanisms. Conversely, lightpath re-provisioning has only recently been considered as an alternative for improving overall network restorability in the event of dual failures. Here, post-failure re-provisioning establishes new backup capacity for unprotected connections in advance of a second failure. Now conventional re-provisioning schemes identify a list of unprotected connections that must be re-provisioned after recovery from the first failure. In this paper we propose a new re-provisioning algorithm to improve the restorability of shared optical networks and compare its performance with such conventional schemes. Namely, the proposed algorithm only requires re-provisioning of a fraction of unprotected connections, since upon re-routing onto shared backup capacity, some connections are only in a temporarily unprotected state. Hence these connections will become available once new working lightpaths are provisioned for the failed connections. Through simulation analysis, we demonstrate the effectiveness of the proposed approach in improving optical network restorability with and without wavelength conversion." } @INPROCEEDINGS{Assi0505:Impact, AUTHOR="Chadi Assi and Wei Huo and Abdallah Shami", TITLE="Impact of Resource Sharability on Dual Failure Restorability in Optical Mesh Networks", BOOKTITLE="NETWORKING 2005", ADDRESS="Waterloo, Ontario, Canada", DAYS=2, MONTH=may, YEAR=2005, ABSTRACT="Protection capacity reprovisioning mitigates the impact of double-link failures by provisioning new capacity for unprotected demands in a network designed to achieve 100\% restorability under single-link failures. We study the performance of reprovisioning in networks under various resource sharing degrees, where higher sharability index implies that more connections are packed together. Intuitively, the lower is the sharability degree of resources the smaller is the number of unprotected connections resulting after the recovery from a failure. However, in this paper we show that limited resource sharability also implies limited flexibility for the network in finding capacity for unprotected demands after failures and accordingly limits the performance of reprovisioning in improving the network restorability. We study the performance of different reprovisioning algorithms under distributed control and we show that contentions severely impact the restorability performance. Finally, we propose a simple mechanism to mitigate the effects of contentions." } @INPROCEEDINGS{Aste0505:Estimation, AUTHOR="Nicola Aste and Mauro Isola and Luigi Atzori", TITLE="Estimation of Multifractal Parameters in Traffic Measurement: an {Accuracy-Based} {Real-Time} Approach", BOOKTITLE="ICC 2005 Communications QoS, Reliability and Performance Modeling", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="In this paper we address the problem of real-time estimation of multifractal parameters of network traffic, which is important in traffic management. The algorithm accuracy is the major concern in the proposed algorithm. From a statistical point of view, it rapidly increases increasing the number of samples used for the estimations. However, the network traffic in long intervals of time may have a heterogeneous scaling behavior, which would make the estimation results meaningless. We then propose an adaptive strategy that adjusts the length of the estimation interval on the basis of the local traffic features so as to extend the number of used sample as much as the traffic behavior is deemed to be stationary. To develop this strategy, we first analyze the temporal evolution of the scaling behavior in real traffic traces. Simulation results show that the proposed algorithm is characterized by a higher accuracy respect to a fixed approach." } @INPROCEEDINGS{Asth0503:Problem, AUTHOR="Somil Asthana and Dimitris Kalofonos", TITLE="The Problem of Bluetooth Pollution and Accelerating Connectivity in Bluetooth {Ad-Hoc} Networks", BOOKTITLE="3rd Annual IEEE International Conference on Pervasive Computing and Comunications", ADDRESS="Hawaii, USA", DAYS=8, MONTH=mar, YEAR=2005, ABSTRACT="This paper investigates a real-world problem termed ``Bluetooth (BTH) pollution'', which is expected to become commonplace as the mass deployment of BTH devices continues. BTH pollution is caused by the presence of a large number of non-cooperating BTH devices within the same radio coverage area, which beyond introducing radio interference also affect each other's basic BTH operations such as discovery, paging and connection setup. The overall result can be a significant slow-down in BTH networking operations, e.g. ad-hoc network formation and healing. We believe the effect of BTH pollution is largely ignored in the BTH ad-hoc networking literature. In this paper we provide an insight on the causes of this problem, as well as simulation and experimental results that illustrate it. Finally, we propose a solution to accelerate BTH ad-hoc networking based on the use of the Class of Device (CoD) information specified in the BTH standard." } @INPROCEEDINGS{Asth0510:Experimental, AUTHOR="Somil Asthana and Dimitris Kalofonos and Parijat Shah and Chunming Qiao", TITLE="An Experimental {End-Node} Architecture and Communication Middleware For Dynamic Proximity Networks", BOOKTITLE="BroadNets 2005 Applications and Services Symposium", ADDRESS="Boston, MA", DAYS=3, MONTH=oct, YEAR=2005, ABSTRACT="In this paper, we describe our experience in implementing an experimental end-node architecture and communications middleware that enables devices (a) to create and support ad-hoc connectivity and active TCP sessions in the absence of infrastructure support, (b) to heal network partitions and resume TCP sessions in case of disconnection, (c) to detect any infrastructure services available (e.g. WLAN AP) and use them, and (d) to discover devices currently attached to the network. The objective of this research is to leverage on existing solutions for various problems we face today in establishing and maintaining IP ad-hoc networks. In broader terms, our communications middleware includes a Connection Manager (CM) that provides and maintains the link-level and IP infrastructure, uses WLAN AP services, and heals network partitions as they occur, and a Session Manager (SM), which provides end-to-end active TCP-session support against intermittent connectivity and IP address changes. Finally, we provide some experimental results for a working implementation (model) of our communications middleware on Linux devices by running applications like a distributed filebrowser and a multiplayer game." } @INPROCEEDINGS{Astr0505:Processing, AUTHOR="Igor Astrov", TITLE="Processing of {Two-Dimensional} Data with use of {Two-Rate} Kohonens Neural Networks", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT={One of the attractive areas of mutirate phenomena research is that of image recognition. In this paper is offered the two-rate recognition of the English alphabet by means of the Kohonens neural networks. The received two-rate Kohonens neural network not only is capable to distinguish the input images, but also is capable to restore images. Further analysis of obtained neural networks can be produced by means of the modern computer software. In example of this paper, the two-rate Kohonens neural network is consisted of the {"}fast{"} and {"}slow{"} subsystems. The structure of the {"}fast{"} subsystem is simpler than the structure of the {"}slow{"} subsystem. The {"}fast{"} part of two-rate Kohonens neural network classifies an image, and the {"}slow{"} part of this neural network restores this image. If the {"}fast{"} neural network meets an unfamiliar image, it means that this image is not the letter of the English alphabet and this image must be carried to a new class. Having determined each number of a class by unique constant, it is possible to apply a {"}fast{"} segment of the neural network for image recognition. The image as a two-dimensional input data is presented. It has been established, that at multiple change of the size of image, the vector of attributes of a class does not change. All the images should be resulted in uniform dimension, and the classification output of the {"}fast{"} neural network should be resulted as a binary code. For the successful work, the additional decoding addresses of inputs and controlled segments of the {"}slow{"} neural network and synchronization of the combined neural network are entered. The simulations for the two-rate Kohonens neural network were carried out in a MATLAB/Simulink environment. This example shows the computing procedure and applicability of the two-rate Kohonens neural networks for fast-acting image recognition.} } @INPROCEEDINGS{Aswa0505:Error, AUTHOR="Chaodit Aswakul and Javier Barria", TITLE="Error Analysis of Multiservice {Single-Link} System Studies Using Linear Approximation Model", BOOKTITLE="ICC 2005 Communications QoS, Reliability and Performance Modeling", ADDRESS="Seoul, Korea", DAYS=16, MONTH=may, YEAR=2005, ABSTRACT="This paper presents an error analysis of the linear approximation model in a multiservice single-link system with nonlinear equivalent capacity. Two types of error measures have been proposed, namely, the mean error and probabilistic error bounds. Derivation of these error measures reveals that the linear approximation model has two main error sources, i.e., the nonlinearity in equivalent capacity and the fluctuation of system dynamics at the mean operating point. In addition, given the product-form solution of the system with the complete sharing policy, a numerical procedure is derived to facilitate the calculation of proposed error measures. This procedure requires both the time and space complexity of $O(Ck)$, where $C$ is the link capacity and $k$ is the number of call types. Hence, these error measures can be efficiently computed in parallel to all the main system performance parameters (call blocking probabilities and mean revenue rates)." } @INPROCEEDINGS{At0506:Statistical, AUTHOR="Nuray At and Huseyin Akcay", TITLE="Statistical Analysis of the Central Algorithm", BOOKTITLE="Canadian Workshop on Information Theory", ADDRESS="Montreal, Quebec", DAYS=5, MONTH=jun, YEAR=2005, ABSTRACT="In this paper, we study the statistical properties of the central algorithm in a one-dimensional parameter space setting assuming that the regressor signal and its inverse are magnitude bounded. We derive non-asymptotic, order-tight, lower and upper bounds on the convergence rate of the parameter estimate variance for the central algorithm. This presents an extension of the previous work for constant scalar regressors to arbitrary scalar regressors save for magnitude constraints." } @INPROCEEDINGS{Atam0509:Empirical, AUTHOR="Stefan Ataman and Armelle Wautier", TITLE="An Empirical Model for the {Inter-Cell} Interference in a {CDMA} Uplink", BOOKTITLE="16th International Symposium on Personal Indoor and Mobile Radio Communications", ADDRESS="Berlin, Germany", DAYS=11, MONTH=sep, YEAR=2005, ABSTRACT="In this paper we propose an empirical model for the inter-cell interference factor (also known as f factor or out-cell interference factor) in the uplink of a CDMA cellular system. The empirical model is introduced for various scenarios. Our simulation results as well as results found in literature are compared with the predictions of the empirical model. With the aid of the proposed model we show a new means to calculate the cell capacity of a CDMA system for a given outage probability." } @INPROCEEDINGS{Atee0505:Current, AUTHOR="Arjumand Ateeg and Luck Kumer and Martin Bednarek and Shaowen Song", TITLE="Current and Future Developments Related to the {SONET/SDH}", BOOKTITLE="Canadian Conference on Electrical and Computer Engineering 2005", ADDRESS="Saskatoon Inn", DAYS=1, MONTH=may, YEAR=2005, ABSTRACT="The insatiable desire for increased bandwidth led to the development and deployment of optical technology. However the potential of this technology has not yet been fully exploited. Currently, SONET/SDH (Synchronous Optical Network/Synchronous Digital Hierarchy) sets the standard for optical communications with the bit rates ranging from 51Mbps to 9.8Gbps per wave length channel. Although Wavelength Division Multiplexing (WDM) has been deployed, the number of wavelength channels per fiber is relatively small at the current time. Dense WDM (DWDM) which better utilizes the fiber capability will further boost the SONET capacity, along with the next generation bit rate of 40Gbps. Current research and development in this area is utilizing this high bandwidth availability for future integrated data transmissions, such as packets over SONET, broadcast TV, video on demand, and video conferencing. These applications will in turn induce a fundamental impact on the SONET itself, which leads to a new generation of technologies evolving from SONET/SDH, such as MPLS (Multiple Protocol Label Switching) and all optical switching. The objective of this paper is to provide an overview of the current state of SONET/SDH, in terms of the technology deployed and the protocols currently in use, and a discussion on future applications and the movement towards 3G Transport Systems. The new technologies and products that are currently being developed in the industry by companies such as CISCO and NORTEL will be explored. The up-coming protocols for future applications tailored specifically for the 3G transport network will be analyzed. MPLS, which is the emerging protocol for interfacing the SONET/SDH optical network, will be explored. We will finally draw up a conclusion about the future of the SONET/SDH in terms of the practicality of the proposals presented." } @INPROCEEDINGS{Atha0504:DEVELOPMENT, AUTHOR="Nikos Athanasopoulos", TITLE="{DEVELOPMENT} {OF} A {PHASED} {ARRAY} {FULL} {DUPLEX} - {CONFORMAL} {CYLINDRICAL} 10 {GHz} {ANTENNA} {SYSTEM} {INCORPORATING} {RADIATION} {PATTERN} {OPTIMIZATION} {ALGORITHMS}", BOOKTITLE="Loughborough Antennas and Propagation Conference 2005", ADDRESS="Burleigh Court Conference Centre", DAYS=4, MONTH=apr, YEAR=2005, ABSTRACT="The development of a phased array conformal antenna