Conferences, Lectures, & Seminars
Events for June
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Mathematical Analysis of Throughput Bounds in Random Access with ZigZag Decoding
Tue, Jun 02, 2009 @ 10:00 AM - 10:30 AM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Jeongyeup Paek,
USC PhD CandidateAbstract: We investigate the throughput improvement that ZigZag decoding (Gollakota and Katabi (2008)) can achieve in multi-user random access systems. ZigZag is a recently proposed 802.11 receiver design that allows successful reception of packets despite collision. Thus, the maximum achievable throughput of a wireless LAN can be significantly improved by using ZigZag decoding. We analyze the throughput bounds in three different idealized slotted multi-access system models for the case when ZigZag decoding is used. We also provide results for the Aloha and CSMA models where exact closed form solutions are infeasible to calculate. Our analysis and simulation results show that ZigZag decoding can significantly improve the maximum throughput of the random access system.Biography: Jeongyeup Paek is a Ph.D. student at Computer Science Department, University of Southern California, advised by Dr. Ramesh Govindan. He recieved his B.S. degree from Seoul National University in 2003 and his M.S. degree from USC in 2005, both in Electrical Engineering. Jeongyeup Paek's research has focused on topics in wireless sensor network systems such as reliable transport protocols, architecture for tiered embedded networks, and sensor network applications such as structural health monitoring.Host: Michael Neely, mjneely@usc.edu, EEB 520, x03505Location: 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. -
Delay Reduction via Lagrange Multipliers in Stochastic Network Optimization
Tue, Jun 02, 2009 @ 10:30 AM - 11:00 AM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Longbo Huang,
USC PhD CandidateAbstract: In this paper, we consider the problem of reducing network delay in stochastic network utility optimization problems. We start by studying the recently proposed quadratic Lyapunov function based algorithms (QLA). We show that for every stochastic problem, there is a corresponding \emph{deterministic} problem, whose dual optimal solution ``exponentially attracts'' the network backlog process under QLA. In particular, the probability that the backlog vector under QLA deviates from the attractor is exponentially decreasing in their Euclidean distance. This suggests that one can roughly ``subtract out'' a Lagrange multiplier from the system induced by QLA. We thus develop a family of \emph{Fast Quadratic Lyapunov based Algorithms} (FQLA) that achieve an $[O(1/V), O(\log2(V))]$ performance-delay tradeoff.These results highlight the "network gravity'' role of Lagrange Multipliers in network scheduling. This role can be viewed as the counterpart of the ``shadow price'' role of Lagrange Multipliers in flow regulation for classic flow-based network problems.Biography: Longbo Huang received the B.E. degree from Sun Yat-sen University, Guangzhou, China in June 2003, and the M.S. degree from Columbia University, New York City, in December 2004, both in Electrical Engineering. He is currently working toward his Ph.D. degree at University of Southern California. His research interests are in the areas of Queueing Theory, Stochastic Network Optimization and Network Pricing.Host: Michael Neely, mjneely@usc.edu, EEB 520, x03505Location: 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. -
Contributions to Measurement-based Dynamic MIMO Channel Modeling and Propagation Parameter Estimatio
Wed, Jun 03, 2009 @ 02:00 PM - 03:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Jussi Salmi,
Helsinki University of TechnologyAbstract: Measurement-based modeling of wireless MIMO propagation channels provides realistic characterization of the physical layer for MIMO transceiver design and network planning. This talk focuses on modeling and parametric estimation of mobile MIMO radio propagation channels. Measured MIMO channels are modeled using a superposition of double-directional, specular-like propagation paths, and a stochastic process describing the diffuse scattering. A state-space modeling approach employing the Extended Kalman filter (EKF) is introduced for sequential estimation of the propagation path parameters from dynamic channel sounding measurements. Moreover, the models are formulated using tensor notation, and a novel tensor decomposition technique is presented. The proposed Sequential Unfolding SVD (SUSVD), has several applications in array signal processing, including a low rank tensor approximation similar to the one obtained using SVD for matrices.Biography: Jussi Salmi was born in Finland in 1981. He received his M.Sc. degree with honors from Helsinki University of Technology, Dept. of Electrical and Communications Engineering, Espoo, Finland, in 2005, and he is currently finalizing his Ph.D. degree. From 2004 to 2005, he worked as a Research Assistant at Radio Laboratory, Helsinki University of Technology. Since 2005 he has held a Researcher position at Dept. of Signal Processing and Acoustics, Helsinki University of Technology. His current research interests include measurement based MIMO channel modeling, parameter estimation, analysis of interference limited multiuser MIMO measurements as well as tensor modeling and decomposition techniques. He has authored a paper receiving the Best Student Paper Award in (EUSIPCO'06), and co-authored a paper receiving the Best Paper Award in Propagation (EuCAP'06).Host: Andreas Molisch, molisch@usc.edu, EEB 530, x04670Location: 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. -
Distributed Sensing with Software Defined Radar Platforms
Wed, Jun 10, 2009 @ 03:00 PM - 04:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Emre Ertin,
Ohio State UniversityAbstract: There has been a surge of interest in the notion of employing large numbers of distributed sensors for applications ranging from environmental monitoring to radar surveillance to biomedical sensing. Envisioned are smart sensor nodes with on-board sensing, computation, storage and communication capability. Such sensing systems simultaneously present unprecedented opportunities and unique challenges in collaborative signal processing. A particular challenge is the need for distributed inference algorithms, which balance the limited energy, computation and communication resources with sensing objectives. In this talk we review resource-constrained signal processing problems in a probabilistic framework and focus on sensor management problem. We consider software defined radar platforms with waveform adaptive transmission capability and study the problem of sensor scheduling for maximizing extracted information from the scene. We present a game theoretic approach to distributed sensor management and compare it with the centralized solution. Next, we propose a non-parametric method for multimodal data fusion of SDR information with other sensing modalities (EO, seismic acoustic) based on generalized likelihood maps. We conclude with experimental results from a layered multimodal data collection campaign at the Ohio State University.Biography: Emre Ertin is a Research Assistant Professor with the Department of ECE and Institue for Sensing Systems at the Ohio State University. He received the BS degree in Electrical Engineering and Physics from Bogazici University, Turkey in 1992, the M.Sc degree in Telecommunication and Signal Processing from Imperial College, UK in 1993, and the Ph.D degree in Electrical Engineering from the Ohio State University in 1999. From 1999 to 2002 he was with the Core Technology Group at Battelle Memorial Institute, as the technical lead for Smart Sensor Technology development. After joining OSU in 2003, he served as PI and co-PI on AFOSR, AFRL, ARL, DARPA, NRL, NIH funded projects on microwave sensor concepts/applications and sensor networks. His current research interests are statistical signal processing, wireless sensor networks, radar signal processing, ocean remote sensing, biomedical signal processing, distributed signal processing and optimization. Host: Urbashi Mitra, ubli@usc.edu, EEB 540, x04667Location: 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. -
Optimization of Cognitive Networks with Multiuser Detection and Retransmission-Based Error Control
Thu, Jun 18, 2009 @ 02:30 PM - 03:30 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Marco Levorato,
University of PadovaAbstract: The original cognitive rationale proposed by Mitola in his Ph.D. thesis has found several applications in wireless networks. In a widely investigated scenario, unlicensed cognitive terminals, namely secondary users, access licensed bands with the aim of improving channel usage of wireless networks. Secondary users are required to adopt smart strategies in order to generate a limited interference to the owners of the bandwidth, namely primary users. Most prior work investigated this scenario with a channel sensing approach, by which the secondary users access the channel in frequency/time slots left unused by the primary users. Other work considers the superposition of secondary and primary users' signals with an interference temperature approach.In this work, we address the optimization of a multiuser detection cognitive wireless network with multiple primary and secondary users, where transmissions by the various nodes of the network can be superposed in time and frequency. We model outage events in the network due to interference and fading and we assume that the nodes implement retransmission-based error control. The main contribution of our analysis is the accurate modeling of the interaction among the stochastic processes tracking the evolution of the nodes in the network. In fact, due to interference the operations of each users influences the evolution of the state of the others.Biography: Marco Levorato received both the BSc (Electronics and Telecommunications Engineering) and the MSc (Telecommunications Engineering) summa cum laude from the University of Ferrara (Italy) in 2002 and 2005, respectively. He received a Ph.D. degree from the doctoral School of Information Engineering, University of Padova in 2008. In 2008 he has been a visiting student at the University of Southern California, Los Angeles, under the supervision of Prof. Urbashi Mitra. Since 2009 Dr. Levorato is a post-doctoral research fellow at the University of Padova. His research interests mainly focus on wireless networking, especially in the stochastic modeling of MIMO networks, cooperating systems, error control protocols and cognitive networks.Host: Urbashi Mitra, ubli@usc.edu, EEB 540, x04667Location: 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. -
Scheduling To Balance Energy & Delay
Thu, Jun 25, 2009 @ 11:00 AM - 12:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Special Networks & Control SeminarProf. Adam Wierman
Computer Science Department, Caltech
Abstract:
No longer is faster always better in system design. Nowadays, speed costs power
and power costs money -- so performance must be balanced with energy usage.
The most common approach for balancing energy consumption and performance is
dynamic speed scaling, which adapts the processing speed to the current workload.
The focus of this talk is to understand some fundamental questions about speed
scaling, such as:
What are the optimal speeds? How do the optimal speeds depend on the
scheduling of the system? What improvement does dynamic speed scaling provide
over simple schemes such as "sleep when idle"?
Speaker Bio: Adam Wierman is an Assistant Professor of Computer Science at the
California Institute of Technology, where he is a member of the Lee Center for
Advanced Networking, the Center for the Mathematics of Information, and the
Social and Information Sciences Laboratory. He received his PhD (2007) and MS
(2004) in Computer Science from Carnegie Mellon University under the
supervision of Mor Harchol-Balter where he was a co-recipient of the
Distinguished Dissertation Award. He also briefly served as a visiting researcher at
the EURANDOM institute under the supervision of Onno Boxma and Ivo Adan.
He is a recipient of an NSF Graduate Research Fellowship, a Siebel Scholars
Fellowship, an ACM Sigmetrics best student paper award, and multiple teaching
awards, including the Alan J. Perlis Student Teaching Award and the Carnegie
Mellon University Graduate Student Teaching Award.Host: Rahul Jain; Assistant Professor; EE-Systems rahul.jain@usc.eduLocation: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Rahul Jain
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.
