HONG KONG BAPTIST UNIVERSITY
FACULTY OF SCIENCE

Department of Computer Science Colloquium
2007 Series

Optimal Multicast in Undirected Networks

Dr. Zongpeng Li
University of Calgary. Canada

Date: August 31, 2007 (Friday)
Time: 10:00 - 11:00 am
Venue: SCT909, Cha Chi Ming Science Tower, Ho Sin Hang Campus

Abstract
In communication networks, multicast models the dissemination of common information from a single source towards a group of receivers. A canonical example of multicast is the streaming of live or stored media over the Internet towards thousands of users at the same time. Optimal multicast here refers to multicast routing that targets maximum throughput, under network topology and link capacity constraints. In this talk, We will review traditional models for multicast based on multicast trees, which is intuitive to understand but makes optimal multicast routing NP-hard. We then introduce the concept of network coding, and discuss a new, network flow based multicast routing model enabled by network coding. We show that in the new model, optimal multicast can be modelled as linear optimization, under various settings, including classic undirected networks. We will also discuss the coding advantage, i.e., the maximum throughput improvement that is possible by the application of network coding. We prove finite bounds for the coding advantage in undirected networks, contrasting the fact that the coding advantage can be arbitrarily large in directed networks.

Biography
Zongpeng Li received his B.E. degree in Computer Science and Technology from Tsinghua University (Beijing) in 1999, his M.Sc degree in Computer Science from University of Toronto in 2001, and his Ph.D. degree in Electrical and Computer Engineering from University of Toronto in 2005. He has been working as an assistant professor at the Department of Computer Science in the University of Calgary since August 2005. Zongpeng was named an Edward S. Rogers Sr. Scholar in 2004, won the Alberta Ingenuity New Faculty Award in 2007, and is currently nominated for the Sloan Research Fellowship, a prestigious award that recognizes top young scientist across Canada and the United States of America.

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http://www.comp.hkbu.edu.hk/v1/?page=seminars&id=67&lang=sc
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