NC State University

Department of Computer Science Colloquia 2001-2002

Date:   Wednesday, March 20, 2002
Time:   3:30 PM (talk)
Place:   402A Withers, NCSU Historical Campus (click for courtesy parking request)

Speaker:  Chenyang Lu , Computer Science, University of Virginia

Quality of Service in Unpredictable Computing Environments

Abstract:   The recent five years have seen phenomenal growth of open systems requiring Quality of Service (QoS) guarantees in unpredictable environments. Examples of such QoS critical systems include E-business servers carrying service level agreements with clients, and pervasive computing systems that monitor and control volatile physical environments in real-time. I have developed a control-theoretic framework for providing QoS guarantees in unpredictable environments. In contrast to heuristics-based adaptive systems relying on hand-tuning/testing iterations, my framework provides a general methodology for applying control theory to design software feedback control with proven QoS guarantees. To integrate control theory with practical system solutions, I designed and implemented control-theory-based QoS software architectures in three representative QoS critical systems. My talk will focus on a new Web server architecture that provides relative delay guarantees to different service classes. I will also briefly describe the application of my framework on enterprise-scale storage servers and real-time processor scheduling in embedded systems. The successful instantiations in these different systems demonstrate the generality and strength of my control-theoretic QoS framework. In the end of the talk I will introduce a middleware that enables the provisioning of control-theoretic QoS guarantees in a wide range of server systems by isolating programmers from control theory concerns.

Short Bio:   Chenyang Lu is a research scientist at the Department of Computer Science of University of Virginia. He also worked as a research intern at the Storage Systems Program of HP Labs (Palo Alto) during the summer of 2000. He received a BS in Computer Science from the University of Science and Technology of China in June 1995, a MS in Computer Science from the Chinese Academy of Sciences in July 1997, and a Ph.D in Computer Science from the University of Virginia under the supervision of Jack Stankovic in May 2001. He has a range of interests in the system area including Internet servers, networked embedded systems, real-time systems, and storage systems.

Host:   R. Fornaro and F. Mueller, Computer Science, NCSU

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