Determination of synchronization errors for clocks in distributed networks

Ming Cao (the University of Groningen)

SYSTEMS AND CONTROL SERIES

DATE: 2011-04-11
TIME: 17:30:00 - 18:20:00
LOCATION: Engineering Lecture Theatre
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ABSTRACT:
While many time synchronization protocols for clocks in wired and/or wireless networks are under development, recently it has been shown by Freris, Graham and Kumar that clocks in distributed networks cannot be synchronized precisely even in idealized situations. By determining the clock synchronization errors in the similar settings of the impossibility result just mentioned, we are able to show that the clocks can get synchronized within an acceptable level of accuracy. After studying the basic case of synchronizing two clocks with asymmetric time delays in the two-way message passing process, we first analyze the directed ring networks, in which neighboring clocks are likely to experience severe asymmetric time delays. We then discuss connected undirected networks with bidirectional message passing between each pair of adjacent nodes. Finally we extend the discussions to networks with directed topologies that are strongly connected.
BIO:
Ming Cao is currently an assistant professor of Discrete Technology and Production Automation with Faculty of Mathematics and Natural Sciences at the University of Groningen, the Netherlands. He received the Bachelor degree in 1999 and the Master degree in 2002 from Tsinghua University, Beijing, China, and the Ph.D degree in 2007 from Yale University, New Haven, CT, USA, all in electrical engineering. From September 2007 to August 2008, he was a Postdoctoral Research Associate with the Department of Mechanical and Aerospace Engineering at Princeton University, Princeton, NJ, USA. He worked as a Research Intern during the summer of 2006 with the Mathematical Sciences Department at IBM T. J. Watson Research Center, NY, USA. His main research interest is in autonomous agents and multi-agent systems, mobile sensor networks and complex networks. He won the VENI award from the Dutch Organization for Scientific Research (NWO) for talented young researchers conducting innovative research in 2009. He is an associate editor for Systems and Control Letters, and for the Conference Editorial Board of the IEEE Control Systems Society. He is also a member of the IFAC Technical Committee on Networked Systems.