学 术 报 告
报告题目：Staffing and Scheduling to Differentiate Service in Multiclass Time-Varying Service Systems
报告学者： Prof. Yunan Liu
报告者单位：North Carolina State University, USA
摘要：We study a practical queueing system having multiple customer classes, nonstationary customer arrivals, and customer abandonment. We will develop effectivestaffing rules (number of servers) and scheduling policies (assigning newly idle servers to a waiting customer from one of the classes), with the objective of achieving differentiated service levels for each customer class. One notable motivation of this research is the Canadian triage and acuity scale (CTAS) guideline that classifies patients in the emergency department (ED) into five acuity levels. In particular, CTAS requires that “level i patients need to be seen by a physician within ???????? minutes 100????????% of the time", with (????1, ????2, ????3, ????4, ????5) = (0, 15, 30, 60, 120) minutes, and (????1, ????2,????3, ????4, ????5) = (0.98, 0.95, 0.9, 0.85, 0.8). Our goal is to devise new control principles (via staffing and scheduling) to guarantee that P(????i(????)>????i)≤????????, that is, the probability that a class-i customer waits more than ???????????????? does not exceed ???????? at all times for all classes. Our new joint staffing and scheduling policy is both time dependent (which copes with the time variability in arrival pattern) and state dependent (which dynamically captures the stochastic variability in service times and arrival times). Effectiveness of our policy is substantiated by heavy-traffic asymptotic optimality theorems. We also conduct computer simulation experiments to provide engineering confirmation and to gain insights.
报告人简介：Yunan Liu (刘雨楠) is an associate professor at the Industrial and Systems Engineering Department and an associate faculty member of the Operations Research Center of North Carolina State University. His research interests include queueing theory, stochastic modeling, applied probability, simulation, and their applications in service systems including call centers, healthcare, manufacturing, and blockchain systems. He received his M.S. and Ph.D. in Operations Research from Columbia University and B.S. in Electrical Engineering from Tsinghua University.