Control Policies for Dynamical Queue and Flow Networks

April 25, 2011, 2001 ESB

Ketan Savla

Massachusetts Institute of Technology, Laboratory for Information and Decision Systems


Queueing systems, along with network flow approximations, provide a fruitful framework for several applications such as transportation, production and data networks. In this talk, we present a novel generalization of this framework that explicitly incorporates dynamical aspects inspired by well-known empirical findings. In particular, two scenarios will be discussed. First, we present a novel dynamical queue model in which the service times depend on the utilization history of the server. For such a queue, we show that a simple threshold policy, that releases a task to the server only if its state is below a certain fixed value, is throughput-optimal. Second, we consider a dynamical flow where the flow dynamics is driven by the difference between the inflow and the outflow on the links. For such a flow network, we show that the node-wise routing policies that respond cooperatively to variations in flow densities on local links in fact provide maximum global robustness guarantees under local information constraint. These results rely on technical tools at the intersection of dynamical systems, queues and network flows, and provide key insights into the fundamental performance limits in presence of dynamical effects.

Speaker's Bio

Ketan Savla was born in the town of Dombivli near Mumbai (formerly Bombay) in India in 1982. He finished his secondary school at Model English School in 1997 and higher secondary school at D. G. Ruparel College in 1999. Thereafter, he joined the Department of Mechanical Engineering at the Indian Institute of Technology, Bombay from where he received B. Tech. in 2003. He started his graduate studies at the Department of Mechanical Engineering at the University of Illinois, Urbana-Champaign where he finished M.S. in 2004. He received his M.A. in Applied Mathematics and Ph.D. in Electrical Engineering, both in 2007, at the University of California, Santa Barbara. Since 2007 he is with the Laboratory for Information and Decision Systems at the Massachusetts Institute of Technology, where he was first a postdoctoral associate and now a research scientist.

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