Service-Level Differentiation in Many-Server Service Systems via Queue-Ratio Routing

Operations Research - Tập 58 Số 2 - Trang 316-328 - 2010
Itai Gurvich1, Ward Whitt2
1Kellogg School of Management, Northwestern University, Evanston, Illinois, 60208
2Department of Industrial Engineering and Operations Research, Columbia University, New York, New York, 10027

Tóm tắt

Motivated by telephone call centers, we study large-scale service systems with multiple customer classes and multiple agent pools, each with many agents. To minimize staffing costs subject to service-level constraints, where we delicately balance the service levels (SLs) of the different classes, we propose a family of routing rules called fixed-queue-ratio (FQR) rules. With FQR, a newly available agent next serves the customer from the head of the queue of the class (from among those he is eligible to serve) whose queue length most exceeds a specified proportion of the total queue length. The proportions can be set to achieve desired SL targets. The FQR rule achieves an important state-space collapse (SSC) as the total arrival rate increases, in which the individual queue lengths evolve as fixed proportions of the total queue length. In the current paper we consider a variety of service-level types and exploit SSC to construct asymptotically optimal solutions for the staffing-and-routing problem. The key assumption in the current paper is that the service rates depend only on the agent pool.

Từ khóa


Tài liệu tham khảo

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Thông tin
Thông tin xuất bản

Operations Research

Tập 58 Số 2

316-328

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