Stochastic Modelling and Analysis of Warehouse Operations
By Yeming Gong
This thesis has studied stochastic models and analysis of warehouse operations. After an overview of stochastic research in warehouse operations, we explore the following topics. Firstly, we search optimal batch sizes in a parallel-aisle warehouse with online order arrivals. We employ a sample path optimization and perturbation analysis algorithm to search the optimal batch size for a warehousing service provider, and a central finite difference algorithm to search the optimal batch sizes from the perspectives of customers and total systems. Secondly, we research a polling-based dynamic order picking system for online retailers. We build models to describe and analyze such systems via stochastic polling theory, find closed-form expressions for the order line waiting times, and apply polling-based picking to online retailers. We then present closed-form analytic expressions for pick rates of order picking bucket brigades systems in different storage profiles, and show how to combine storage policies and bucket brigades protocols to improve order picking productivity. Finally, we propose a new warehouse design approach oriented to improving revenue management of public storage warehouses. Our experiments show a proper facility design can significantly improve the expected revenue of public storage warehouses.
About Yeming Gong
Yeming Gong was born in Hubei, China on 1st January 1976. Before he studies in the Netherlands, he studied production and operations management in INSEAD (European Institute of Business Administration), Fontainebleau, France. His research topic was "Stochastic Optimization for the Multi-location Transshipment Problem with Positive Replenishment Lead times", and he received his MSc degree in 2005. Since 2006, he joined the PhD program at Rotterdam School of Management, Erasmus University. In the early stage of his PhD study, he had frequently attended the courses and academic activities in LNMB (Dutch Network on the Mathematics of Operations Research) and TRAIL (the Netherlands Research School on Transport, Infrastructure and Logistics), where he laid a solid foundation, particularly in stochastic operations research and logistics. In Rotterdam School of Management, his main research interests are warehouse operations. His research topics include, approximate optimal order batch sizes in a parallel-aisle warehouse, a flexible performance evaluation framework of order picking systems, storage scheduling decision models for revenue management of selfstorage warehouses, a review on stochastic models and analysis of warehouse operations, and a new design method.