SUNMONTUEWEDTHUFRISAT
Conferences, Lectures, & Seminars
Events for August
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Opportunistic Routing in Wireless Networks: A Stochastic/Adaptive Control Approach
Wed, Aug 19, 2009 @ 11:00 AM - 12:30 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Tara Javidi,
University of California, San DiegoAbstract: Opportunistic routing for multi-hop wireless networks has seen recent research interest to overcome deficiencies of traditional routing. First, we, briefly, cast opportunistic routing as a Markov decision problem (MDP) and introduce a stochastic variant of distributed bellman-ford which provides a unifying framework for various versions of opportunistic routing such as SDF, GeRaF, and EXOR.In the second part of the talk, we touch upon the issue of congestion and throughput optimality by contrasting the opportunistic MDP-based schemes with some back-pressure opportunistic schemes. We propose a modification of the MDP framework to arrive at a throughput-optimal policy, aka ORCD, that exhibits significant delay improvements over existing candidates in the literature. In the process of proving throughput optimality for ORCD, we introduce a new Lyapunov function construction which characterizes an important and large class of throughput optimal policies. The proposed class includes backpressure and ORCD as simple special cases.To formulate and identify the optimal routing strategy, MDP formulations rely on the availability of probabilistic (Markov) models. Lastly (and time-permitting), we build on our earlier work on sensitivity analysis for opportunistic schemes and use a reinforcement learning framework to propose an adaptive opportunistic routing algorithm. The proposed scheme minimizes the expected average cost per packet independently of the initial knowledge about the channel quality and statistics across the network.Biography: Tara Javidi studied electrical engineering at Sharif University of Technology, Tehran, Iran from 1992 to 1996. She received the MS degrees in electrical engineering (systems), and in applied mathematics (stochastics) from the University of Michigan, Ann Arbor, in 1998 and 1999, respectively. She received her Ph.D. in electrical engineering and computer science from the University of Michigan, Ann Arbor, in 2002.From 2002 to 2004, she was an assistant professor at the Electrical Engineering Department, University of Washington, Seattle. She joined University of California, San Diego, in 2005, where she is currently an assistant professor of electrical and computer engineering. She was a Barbour Scholar during 1999-2000 academic year and received an NSF CAREER Award in 2004. Her research interests are in communication networks, stochastic resource allocation, stochastic control theory, and wireless communications.Hosts: Rahul Jain, rahul.jain@usc.edu, EEB 328, x02246
Michael Neely, neely@usc.edu, EEB 520, x03505
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor. -
Ph.D. Dissertation Defense
Wed, Aug 26, 2009 @ 10:00 AM - 11:00 AM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Bumpless Transfer and Fading Memory for Adaptive Switching ControlShin-Young Cheong
Ming Hsieh Department of Electrical Engineering
University of Southern CaliforniaAbstract:
Cheong's Ph.D. dissertation mainly focuses on implementation techniques for adaptive switching control. Adaptive switching control has a possibility to generate bad transients in controller output which can be reduced using various bumpless transfer techniques. A new bumpless transfer method is developed based on slow-fast controller decomposition. The method is especially well-suited to situations in which the plant model is poor or yet to be identified, as may be the case in adaptive switching control.
A new cost function with fading memory and a finite-duration time-window is introduced in order to reduce the effect of old data in unfalsified adaptive control applications where the plant varies slowly or infrequently with time. The effectiveness of the approach is demonstrated via a simple simulation. The result demonstrates that time-windowed/fading-memory cost function for unfalsified control is useful for adaptive control system with
time-varying plants, even when the plant fails to satisfy the usual 'feasibility' requirement of unfalsified control that it must be stabilizable by one of the candidate controllers to satisfy the usual 'feasibility' requirement of unfalsified control that it must be stabilizable by one of the candidate controllers.Biography: Shin-Young Cheong received B.S. degree in Electrical Engineering from Hanyang University,Seoul, Korea, in 2003. He received M.S. degree in 2005 and continued to study for Ph.D. degree in EE at USC.
He is currently studying adaptive switching control and his research interests are control theories including adaptive control, robust control, and optimization in feedback control system.
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 203
Audiences: Everyone Is Invited
Contact: Shane Goodoff
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor. -
Multiple Description Coding: Shannon Meets Wiener and von Neumann
Wed, Aug 26, 2009 @ 02:30 PM - 03:30 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Jun Chen,
McMaster UniversityAbstract: Multiple description coding is a quantization technique for multimedia transmission through unreliable links. A general achievable 2-description rate region was found by El Gamal and Cover, and was shown to be tight for the quadratic Gaussian case by Ozarow. In this talk, I will present a constructive quantization scheme that can achieve the whole Gaussian 2-description rate region. The key idea is that a high dimensional nonlinear quantization system can be converted into a linear system with small nonlinear components. More fundamentally, our scheme reveals an intimate connection between Shannon's theory for digital systems and Wiener's theory for analog systems.Our scheme also suggests a natural inner bound of the rate region for the general $L$-description case. It turns out that the inner bound is tight for quadratic Gaussian multiple description coding with individual and central distortion constraints, which solves a longstanding open problem. Our proof is based on von Neumann°Øs game theory. Specifically, it is shown that the inner bound can be interpreted as a min-max game and the corresponding max-min game yields an outer bound; these two bounds coincide due to the existence of a saddle point.I will also discuss some intriguing connections between multiple description coding and other major problems in network information theory.Biography: Jun Chen received the B.E. degree with honors in Communication Engineering from Shanghai Jiao Tong University, Shanghai, China, in 2001, and the M.S. and Ph.D. degrees in Electrical and Computer Engineering from Cornell University, Ithaca, NY in 2003 and 2006, respectively. He was a Postdoctoral Research Associate in the Coordinated Science Laboratory at the University of Illinois at Urbana-Champaign, Urbana, IL from 2005 to 2006, and a Josef Raviv Memorial Postdoctoral Fellow at the IBM Thomas J. Watson Research Center, Yorktown Heights, NY from 2006 to 2007. He is currently an Assistant Professor of Electrical and Computer Engineering at McMaster University, Hamilton, ON, Canada. He holds the Barber-Gennum Chair in Information Technology.Host: Zhen Zhang, zhzhang@usc.edu, EEB 508
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 539
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor. -
Testing 802.11p WAVE on the Road: An Error-Prone Traffic Telematics Standard
Mon, Aug 31, 2009 @ 10:30 AM - 11:30 AM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Dr. Nicolai Czink,
Stanford UniversityAbstract: Vehicle-to-infrastructure (V2I) systems can make the road safer and its use more efficient, given that the data transmission from and to the road users over the wireless link is timely, accurate, and well presented. Under these conditions, a reduction in the number and severity of accidents can be expected. Furthermore, traffic can be more efficiently managed and congestions can be avoided. The IEEE 802.11p standard for Wireless Access on Vehicular Environments (WAVE) was derived from the 802.11a WiFi standard to support high-speed communications on the road for both road-to-car and car-to-car environments. Already in simulation tests, the standard turned out to fail in common scenarios like driving with high speeds, shadowing by other cars, or simply access by too many vehicles in dense traffic situations.Using the proprietary CVIS testbed, developed in a European research project, we tested the performance limits of 802.11p. This presentation will show that the standard (in its current version) fails to ensure reliable data transmission in almost all environments. The results also provide some guidance for installing WAVE equipment and suggest countermeasures to increase the reliability of the WAVE standard.Biography: Nicolai Czink received his MSc and PhD degrees from Vienna University of Technology in 2004 and 2008, respectively, both with distinction. Since 2005, he is with the ftw. Telecommunications Research Center Vienna, where he is Senior Researcher in the area of wireless communications at present. From April 2008 to April 2009, he was visiting scholar at the Smart Antennas Research Group at Stanford University working on MIMO interference measurements an modeling. His current interests are intelligent transportation systems an cooperative communications.Host: Andreas Molisch, 04670, EEB 530, molisch@usc.edu
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 539
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor.
