Month: February 2017

Suman Jana, Martha Kim, and Vishal Misra of Columbia’s Computer Science Department are each recipients of a Google Research Award, which provides funding to support research of new technologies developed by university faculty. Their three projects are among the 143 selected from 876 proposals received from over 300 universities worldwide. The funding provided by Google will cover tuition for one graduate student and allows faculty and students to work with Google engineers and researchers.

Suman Jana

For using machine learning to automatically find bugs in software, Suman Jana will receive $62K. Specifically his project Building High Coverage Fuzzers using Reinforcement Learning seeks to improve fuzzing, a software testing technique that inputs random data, called fuzz, to try to elicit error responses so the underlying code vulnerabilities can be identified before the software is released publicly and exposed to possible hacking. Current methods of fuzzing begin with seed inputs, applying mutations to produce a new generation of inputs. By evaluating which inputs generate show the most promise in leading to new bugs, fuzzers decide which inputs should be mutated further.

While fuzzing is successful at finding bugs humans might never find, especially simple bugs, the random and unsystematic nature of the evolutionary process means fuzzers might concentrate so much on certain inputs that some code gets overlooked. Jana’s project will employ reinforcement learning—a machine learning technique that reinforces successful actions by assigning reward points—to make the fuzzer more aware of how the software operates so the fuzzer can more intelligently generate input data for the specific program being tested. Rather than determining future inputs based only on the current generation of inputs (as do current fuzzers), reinforcement learning-based fuzzers will consider all previous mutations, finding program-specific patterns of mutations to ensure more complete code coverage. It’s a method that can be re-used since reinforcement learning-based fuzzers, once trained for a particular application, can be used to test other applications with similar input format and functionality.

Martha Kim

For more efficient ways of transcoding video, Martha Kim will receive $70K.

Transcoding video is the process of converting user-generated video to a size and format that views smoothly no matter the viewer being used. For video sharing sites like YouTube—currently uploading 400 hours of video each minute—more efficient transcoding translates to lower processing, storage, and other costs.

Transcoding can be done in software or hardware. While hardware accelerators operate at lower computational costs, they have serious drawbacks when it comes to video: they are slow to market (and thus slow to adapt to the release of updated codecs) and lack quality and other parameter controls that accommodate the varying requirements of a video-sharing site like YouTube, which in contrast to broadcast services such as Netflix, serve a wide-ranging and rapidly growing inventory of videos.

The ideal would be to combine the cost advantages of hardware with the flexibility, control, and upgradability of software, and that is the aim of Kim’s project, Video Transcoding Infrastructure for Video Sharing. By identifying bottlenecks in software video transcoding, Kim will design a video transcoding accelerator that avoids them. Rather than hardcoding entire algorithms into a rigid hardware design, Kim plans a modular approach, using separate building blocks for the different component stages of the transcoding. This modular approach promises to more readily support different video formats and differing quality and cost considerations.

Vishal Misra

Vishal Misra, whose research emphasizes the use of mathematical modeling to examine complex network systems, received $75K to fund Bandwidth allocation strategies for multi data center networks, which investigates strategies for estimating the right amount of bandwidth for data centers. Here the goal is to provide enough bandwidth to meet demand, even at peak times, while avoiding expensive over-provisioning.

The problem is far from simple. Global data centers provide distributed cloud computing for a host of services, all having different bandwidth and priority requirements. Communication may take place between servers within the data center or with servers at different sites.

Current methods for estimating bandwidth requirements (such as Google’s BwE) roughly work by aggregating all inputs to a data center while performing bandwidth control and priority enforcement at the application level according to the principle of max-min fair allocation (where a process with a “small” demand gets what it needs, while unused resources are evenly distributed among processes with unmet requirements).

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But is this the right criteria to use? Misra who has previously investigated congestion equilibrium theory will seek to answer this and other open questions revolving around current allocation methods while also investigating other approaches (for example, separating bandwidth allocation from the traffic engineering problem and studying each independently).

This is the second Google Research Award for Misra. His first in 2009 resulted in the paper Incentivizing peer- assisted services: A fluid shapley value.

– Linda Crane
Posted 2/24/2017