U OF M COLLEGE OF ENGINEERING
CONTROL SEMINAR SERIES
WINTER TERM 1998

Professor Yavuz A. Bozer

Industrial and Operations Engineering
University of Michigan

yabozer@engin.umich.edu

Friday, February 13, 1998
4:00 - 5:00 pm
1200 EECS

Title: Throughput Performance of Automated Storage/Retrieval Systems under Stochastic Demand

• Abstract
  
  In many modern manufacturing systems, centralized work-in-process (WIP) storage is performed by small, i.e., generally one to four-aisle, automated storage/retrieval (AS/R) systems. When used for centralized WIP storage, AS/R systems generally offer a cost-effective solution; they also improve WIP visibility and accuracy, and they typically require less floor space than manual or conventional storage/retrieval systems. Considerable work has been done to develop analytical expressions for estimating the throughput and/or cost of AS/R systems. However, with very few exceptions, existing analytical models do not consider the fact that, when used for centralized WIP storage, requests for storages and retrievals arrive at the system randomly. We discuss why such random arrivals must be considered and how they affect the performance of the system. We also show closed-form analytical results to answer the foremost question in AS/R system design: Given the arrival rates, and given the expected cycle time of the S/R machine, will the system meet the required throughput? We conclude the presentation by: 1. Showing some numerical results (based on analytical and simulation models) concerned with the performance of the system, and 2. Discussing other issues that have not been addressed in the AS/R system design literature but are critical when such systems are used for centralized WIP storage.

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  Biosketch

  
  Yavuz A. Bozer received his BSIE degree from METU, Turkey and his M.S. and Ph.D. degrees in Industrial and Systems Engineering from Georgia Institute of Technology. He received the 1987 IIE Dissertation Award for his dissertation which is concerned with the efficient design and operation of order picking systems. In 1988 he was selected a Presidential Young Investigator by the National Science Foundation. Dr. Bozer's professional experience includes his full-time employment with the SysteCon Division of Coopers & Lybrand where he was involved in the design, analysis, and simulation of material handling systems, and numerous facility layout projects concerned with warehousing and manufacturing operations. Subsequently, he worked for three years at the Material Handling Research Center at Georgia Tech as a full-time Research Engineer.

  Currently, he is an Associate Professor with the Department of Industrial and Operations Engineering at the University of Michigan, Ann Arbor. His teaching and research interests focus on the design and performance evaluation of material flow/storage systems and facilities layout. He has a project with the NSF-ERC concerned with reconfigurable material handling systems and he is the thrust group leader for Factory Optimization and Control at the Center for Display Technology and Manufacturing (DTM). He has been engaged in research and consulting projects with GE, GM, Ford, Xycom, OIS, and Virco, among others. He is a member of IIE and INFORMS.

© UofM College of Engineering Control Research Group - December 1997
bethi@umich.edu