Cenk's defense: 2007-11-28 @3:30PM in EBG11

PhD Dissertation Defense

Değer Cenk ERDİL

erdil@cs.binghamton.edu

Department of Computer Science
Watson School of Engineering and Applied Sciences
Binghamton University

Date: Wednesday, November 28th, 2007  Time: 3:30pm  Location: Engineering Building G-pod Conference Room

ABSTRACT

As grids scale to include more individual resources, improved grid middleware services that eliminate the need for structure and centralization becomes more important. Moreover, the most effective grid middleware services will be adaptive, reacting to their highly dynamic environments.

One important service that must be distributed and scalable is grid resource scheduling. In hybrid grids, resources and jobs are likely to be non-uniformly distributed in space and in time, and thus no single approach to tracking resource information will be effective in all places at all times. Non-uniform information dissemination helps enable large-scale and dynamic grid resource scheduling, with less packet overhead and better localized coverage, which is especially useful when the grid structure is mostly unknown, such as in hybrid grids.

This dissertation describes improved information dissemination protocols that adapt to their environment using feedback from the system. Thus, grid nodes produce different dissemination protocols on-the-fly, where each protocol individually reflects both the characteristics of particular resource and load distributions, and the policies of autonomous grid nodes or regions. The adaptive information dissemination protocols can result in much less packet overhead, with comparable query satisfaction rates, compared to best-case non-adaptive protocols that may be configured for each particular grid resource and load scenario.

Vinay's dissertation defense: 2007-11-28 @8:30AM in EBG11

Ph.D. DISSERTATION DEFENSE
Routing and Traffic Engineering in Multi-hop Wireless Networks: An optimization based approach
Vinay Kolar
vinkolar@cs.binghamton.edu
Dept. of Computer Science, SUNY, Binghamton.
Advisor: Dr. Nael Abu-Ghazaleh
Date: Nov 28, 2007, Wednesday  Time: 8:30 A.M.  Room: EB-G11
Abstract

   Multi-hop wireless networks (MHWNs) attract significant interest due to the minimal infrastructure demands and their potential in supporting mobile and pervasive computing. The high demand placed by a growing user base on the limited available bandwidth places a premium on effective communication and networking for MHWNs. The dissertation targets developing a formally grounded approach to solving routing problems in MHWNs, while taking into account the effects of interference. The work builds on recent efforts in the networking community to express a network as an optimization problem, and decomposing the formulation to provide distributed protocols. A successful model can then be applied to: (1) analyze the performance and capacity of existing protocols; (2) develop protocols for traffic engineering and admission for static networks; and (3) develop formally grounded and near-optimal distributed routing protocols.
   In MHWNs, the problem is substantially more complicated than the wired problem because of interference. Interference is exhibited at many levels, leading to effects such as uncontrolled contention and unfairness. The approach taken by the dissertation is to break the problem into multiple layers.
   Firstly, the dissertation proposes a Multi-commodity flow based routing model that produces interference-separated routes. Interactions between multiple routes are analyzed and effective objective function design is proposed that maximizes the throughputand minimizes the end-to-end delay.
   Nevertheless, such a model is directly employable only in smaller networks due to its NP-hard nature. The second contribution of the dissertation is to approximate the routing model to a polynomial time algorithm. A decomposition based approach is followed to formulate a low-complexity model by applying domain-specific heuristics.
   The simplistic scheduler assumptions in the routing model limits its accuracy in practice. A low-complexity scheduling model is proposed to capture the key scheduling interactions in CSMA based schedulers, like IEEE 802.11, and this model is integrated with the routing model.
   An approach to improve the accuracy of the scheduling model, while preserving a low run-time, is presented. “Interaction graphs” are proposed to capture the scheduling characteristics of CSMA based schedulers. Fairness in CSMA based scheduler for contention of the wireless channel is modeled using Renewal Theory and Continuous-time Markov Chain. Finally, throughput estimation models are proposed for various categories of interactions that have been identified in MHWNs.

Wednesday 11/28/07 talks

Both Vinay and Cenk have dissertation defenses on Wednesday. In lieu of a regular talk, we'll attend these defenses and support our fellow students!

Vinay will go on 8:30am, Cenk's is at 3:30pm.

I don't know the room assignments, but there should be invitations posted around the engineering building on campus.

Video posted of power circuit talk

I have posted the first video. It's from the 2007-10-31 talk by Michael Hines about Controlling Power with the Computer.

The video didn't come out as great as I would have liked. In the future I'll do better sound checks and hopefully will find a better recording tool that make just create avi/divx files.