Optimal Control and Performance Evaluation of Stochastic Service and Manufacturing Systems

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Congestion occurs in service and manufacturing systems with random demands for goods and services, and random processing or service times. The aim of this research is to find effective ways to reduce congestion via stochastic modeling and analysis. It will contribute to three important issues in stochastic service and manufacturing systems: (1) system and policy design for service systems with multi-objectives; (2) competition and coordination of public and private service systems; and (3) reliability improvement for production systems under random shocks. The first issue (particularly relevant with respect to security-check system at airports, border-crossings, or cancer screening systems) will be addressed using simple queuing network structures. A two-stage queuing network (where some customers are required to go through a second stage) can capture the main characteristics of a system in which the objectives of minimizing sampling errors and waiting costs can be traded-off against each other. For the second issue, where achieving maximum social benefit is the main objective, we model the system with a two channel queuing network with customer choice and social planner’s (government’s) intervention. Finally, the third issue will be addressed utilizing more general shock processes to model supply chain interruptions. Compared with classical queuing applications, the proposed research is innovative in its use of queuing models addressing the coordination of public and private service providers and the relation between multiple objectives in a stochastic service system. The results of this research will therefore be relevant to firms and government agencies seeking to design service or systems and/or control policies to improve their efficiency. The proposed research is highly relevant to the challenges faced by Canada-US border crossing systems or airport’s security checkpoints. Findings can support the work of agencies such as Canada Border Services Agency in managing border operations effectively, balancing security and public safety needs with efficient travel and trade. Work on competition and coordination of public and private service systems is highly relevant to Canada’s healthcare system. While politicians in Canada continue to debate the viability of a two-tier public and private healthcare system (as they already exists in Australia and some European countries), no quantitative congestion analysis for evaluating such a system exists. Outputs from my research can make a significant contribution to the ability of Provincial Governments to design sustainable and affordable healthcare systems. Finally, the proposed work on reliability improvement for production systems under random shocks will help Canadian supply chain organizations with international suppliers or customers to improve the operational reliability of their firms in an uncertain global environment subject to natural disasters and/or political turmoil.