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                Department of Systems Engineering and Engineering Management
                             The Chinese University of Hong Kong

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Date: Monday, 4:30pm - 5:30pm, 21 September, 2015

Title: Scaling and Staffing for Call Center Management

Speaker: Xiaowei Zhang, Assistant professor in the Department of Industrial Engineering and Logistics Management, Hong Kong University of Science and Technology.

Abstract:

The Poisson process has been an integral part of many models for the arrival process to a telephone call centers. However, various publications in recent years suggest the presence of a significant "overdisperson" relative to the Poisson process in real-life call center arrival data. In this paper, we study the overdispersion in the context of heavy traffic and identify a critical factor that characterizes the stochastic variability of the arrivals relative to their averages. We refer to such a factor as the scaling parameter as it determines the appropriate way to scale the arrival process in heavy traffic. Indeed, data exhibits that the square-root scaling as in the conventional central limit theorem may not truly reflect the reality. We propose a new stochastic model to capture the scaling parameter and develop the associated staffing rule in the QED (quality-and-efficiency driven) regime. The new staffing rule stipulates that in order to achieve a balance between quality-of-service and agent efficiency, the safety margin of the staffing level ought to have an order of magnitude that depends on the scaling parameter. In particular, in the presence of overdispersion the safety margin has an higher order of magnitude than what the square-root staffing rule suggests. We apply the new staffing rule to real data and find out it significantly outperforms the square-root staffing rule.

Biography:

XIAOWEI ZHANG is an Assistant Professor in the Department of Industrial Engineering and Logistics Management at Hong Kong University of Science and Technology. He received his Ph.D. in Operations Research from Stanford University in 2011. He is a member of INFORMS and his research interests include stochastic simulation and data-driven service engineering.

Everyone is welcome to attend the talk!

Venue: Room 513,

       William M.W. Mong Engineering Building (ERB),

       (Engineering Building Complex Phase 2)

       The Chinese University of Hong Kong.

The talk will be hosted by:

Prof. Gao Xuefeng,

Department of Systems Engineering and Engineering Management,

The Chinese University of Hong Kong,

E-mail: xfgao@se.cuhk.edu.hk

Homepage: http://www.se.cuhk.edu.hk/people/xfgao.html