报告人：Yunan Liu

主持人：郭永江

报告时间：2018年7月16日10:00---11:00

报告地点：主楼1214

报告摘要：

There are two basic queue structures commonly adopted in service systems: the pooled structure where waiting customers are organized into a single queue served by a group of servers and the dedicated structure where each server has her own queue. Although the pooled structure, known to minimize the servers’ idle times, is widely used in large-scale service systems, this study reveals that the dedicated structure, along with the join-the-shortest-queue routing policy, could be more advantageous for improving some service levels, such as the probability of a customer’s waiting time being within a delay target. The servers’ additional idleness resulted from the dedicated structure will be negligible when the system has many servers. Using a fluid model substantiated by asymptotic analysis, we provide a performance comparison between the two structures for a moderately overloaded queueing system with customer abandonment. We intend to help service system designers answer the following questions: To achieve a specified service level, which queue structure will be more cost-effective? How many servers can be saved by converting one structure into the other? Aside from structure design, our results are also of practical value for performance analysis and staffing deployment.

报告人简介：

Yunan Liu obtained his B.E. degree from the Electrical Engineering Department at Tsinghua University, M.S. and Ph.D. degrees from the Industrial Engineering and Operations Research Department at Columbia University. Yunan Liu is currently an associate professor at North Carolina State University. His research interests include stochastic modeling, applied probability, simulation, optimal control and queueing theory, with applications to customer contact centers, health care, production and transportation systems. Yunan Liu’s personal website:http://yunanliu.wordpress.ncsu.edu