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Please join the OM group to hera from Dr. Hrayer Aprahamian from Texas A&M University.

Date: Friday, November 11th

Time: 11:00 am

Location: Bidgood 34


Title: An Optimization-based Scheduling Framework for Multi-service Appointment Systems with Non-stationary Arrival Processes


Abstract: In this work, we analyze multi-service appointment systems with non-stationary arrival processes. The main goal is to identify server schedules that lead to good-performing systems, which we measure through the expected waiting time and the number of customer rejections. This decision problem arises in a number of applications and is especially relevant when certain service types dominate others.  A key challenge in this analysis is the lack of closed-form analytical expressions that characterize the performance of the system. In this work, we construct a stylized optimization model that approximates the original stochastic system. An analysis of a problem instance comprised of a single service type leads to key structural properties which we use to devise a globally convergent solution scheme that runs in polynomial time. This solution scheme is then generalized to the case of multiple service types for two different formulations of the problem. To demonstrate the effectiveness of the proposed framework, we conduct a case study on Texas A&M University’s Counseling and Psychological Services. Our results demonstrate that our optimal solutions substantially improve the performance of the system over current practices and increase access to critical mental health services by as much as 55%.


Bio: Dr. Hrayer Aprahamian is an Assistant Professor at the Wm. Michael Barnes Department of Industrial and Systems Engineering at Texas A&M University. He received his Ph.D. in Industrial and Systems Engineering from Virginia Tech in 2018. Dr. Aprahamian’s research interests lie at the interplay between combinatorial/discrete and continuous optimization, with particular interest in applications related to healthcare systems and public policy decision-making. His research papers have appeared in journals such as Management Science, INFORMS Journal on Computing, Stochastic Systems, and IISE Transactions. He was awarded the 2022 Pierskalla Best Paper Award, was a finalist for the 2021 JFIG Paper competition, received the IISE Transactions Award in 2020, the Pritsker Doctoral Dissertation Award in 2019, the Paul E. Torgersen Research Excellence Award in 2018, and was runner-up for the 2017 Pierskalla Best Paper Award.

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