Optimal Control and Performance Evaluation of Stochastic Service and Manufacturing Systems

拥塞发生在对商品和服务的随机需求以及随机处理或服务时间的服务和制造系统中。本研究的目的是通过随机建模和分析来寻找有效的减少拥堵的方法。这将有助于研究随机服务和制造系统中的三个重要问题：(1)多目标服务系统的制度和政策设计；(2)公私服务体系的竞争与协调；(3)提高随机冲击下生产系统的可靠性。第一个问题（特别是与机场安全检查系统、过境点或癌症筛查系统有关的问题）将使用简单的排队网络结构来解决。两阶段排队网络（其中一些客户需要经过第二阶段）可以捕获系统的主要特征，在该系统中，最小化抽样误差和等待成本的目标可以相互权衡。对于第二个问题，实现最大的社会效益是主要目标，我们用客户选择和社会规划者（政府）干预的双通道排队网络对系统进行建模。最后，第三个问题将利用更一般的冲击过程来模拟供应链中断。与传统的排队应用相比，本研究创新性地使用了排队模型来解决公共和私人服务提供者之间的协调以及随机服务系统中多个目标之间的关系。因此，这项研究的结果将与寻求设计服务或系统和/或控制政策以提高其效率的公司和政府机构有关。拟议的研究与加拿大-美国边境过境系统或机场安全检查站面临的挑战高度相关。调查结果可以支持加拿大边境服务局等机构的工作，有效地管理边境行动，平衡安全和公共安全需求与高效的旅行和贸易。公营和私营服务系统的竞争和协调工作与加拿大的医疗保健系统高度相关。当加拿大的政客们继续争论双层公共和私人医疗保健系统的可行性时（就像澳大利亚和一些欧洲国家已经存在的那样），没有定量的拥堵分析来评估这种系统。我的研究成果可以为省政府设计可持续和负担得起的医疗保健系统的能力做出重大贡献。最后，关于随机冲击下生产系统可靠性改进的建议工作将帮助加拿大供应链组织与国际供应商或客户在不确定的全球环境中提高其公司的运营可靠性，受到自然灾害和/或政治动荡的影响。

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.