Fair Dynamic Routing in Large-Scale Heterogeneous-Server Systems
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Date: 10-28-2008
Start Time:
1:00pm
End Time: 2:00pm
Speaker: Mor Armony, Stern School of Business: New York University
Location: 303 Mudd
ABSTRACT
In a call center, there is a natural trade-off between minimizing customer wait time and fairly dividing the workload amongst agents of different skill levels. The relevant control is the routing policy; that is, the decision concerning which agent should handle an arriving call when more than one agent is available. We formulate an optimization problem for a call center with multiple agent pools, that handle calls at a different speed, and a single customer class. The objective is to minimize steady-state expected customer wait time subject to a "fairness" constraint on the workload division.
The optimization problem we formulate is difficult to solve exactly. Therefore, we solve the diffusion control problem that arises in the many-server heavy-traffic QED limiting regime. The resulting routing policy is a threshold policy that prioritizes faster agents when the number of customers in the system exceeds some threshold level. We prove our proposed threshold routing policy is near-optimal as the number of agents increases, and the system load approaches its maximum processing capacity.
This is joint work with Amy Ward from the Marshall School of Business, University of Southern California.
BIO
Mor Armony is an assistant professor of operations management at New York University Stern School of Business. Professor Armony teaches courses in competitive advantage from operations and in stochastic modeling. Professor Armony's primary research areas of interest include information services, resource allocation in the presence of uncertainty and stochastic modeling of various operations. Her articles have appeared in numerous publications.
Most recently, she has been published in Management Science, Operations Research and Queueing Systems. Before joining NYU Stern, Professor Armony served as a consultant for Lucent Technologies and for AT&T. She also developed mathematical models for the prediction of financial indexes at Eventus, Israel. Professor Armony received her Bachelor of Science in mathematics and statistics and her Master of Science in statistics from the Hebrew University of Jerusalem. She also received a Master of Science and a Doctor of Philosophy in engineering-economic systems and operations research from Stanford University.