OR Colloquium

Event Details
  • Date/Time:
    • Friday November 9, 2012 - Saturday November 10, 2012
      10:00 am - 10:59 am
  • Location: IC 117
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David Goldberg



Summary Sentence: OR Colloquium

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TITLE: Dynamic Control of Service Systems: some challenges, some answers

SPEAKER:  Mark Lewis


In this talk, I will present several classical decision-making paradigms revised for today's environment. In particular, in the service economy models of call centers and health care systems include abandonments. Assuming customer patience is exponential, modeling basic systems with continuous-time Markov processes remains valid, but analyzing them using uniformization is not. This means that discrete-time Markov decision process theory (and the accompanying successive approximations) cannot be used. Similarly, in health care systems arrivals to emergency departments are rarely stationary. We mention how to extend MDP theory to more general state spaces. Finally, can the two challenges be met together? Open problems are discussed.


Professor Lewis received his Ph.D. in Industrial and Systems Engineering from the Georgia Institute of Technology in 1998. After receiving his doctorate, Lewis spent a year at the University of British Columbia as a postdoctoral fellow in the Center for Operations Excellence. He joined Cornell's School of Operations Research and Information Engineering in 2005 after teaching Industrial and Operations Engineering at the University of Michigan.

Broadly speaking Professor Lewis's research interests are on the dynamic control of service systems. Most often he uses the methodology of stochastic dynamic programming or Markov decision processes to analyze these problems. Along the way he has done fundamental research on the theory of MDPs. In the area of average cost MDPs on general state and action spaces he has studied convergence of discounted cost optimal values and policies and on a refinement of average cost theory called bias optimality he has studied implicit discounting. In terms of applications, Professor Lewis has considered routing in transportation systems, control of inventory systems and allocation of inter-switch handoffs in wireless communications. Despite his versatility in the analysis of such systems his passion is for resource allocation in controlled queueing networks. In doing so, he has considered non-stationary networks, networks with limited capacity and those with varying service capabilities.


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School of Industrial and Systems Engineering (ISYE)

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  • Created By: Anita Race
  • Workflow Status: Published
  • Created On: Nov 5, 2012 - 4:04am
  • Last Updated: Oct 7, 2016 - 10:01pm