Canadian Operational Research Society

Calgary Section

http://www.corscalgary.org/

PROFESSIONAL DEVELOPMENT SEMINAR

When: Noon to 1:30 PM, Friday, April 16, 2004

Room 217

TransCanada Tower

450 - 1 Street SW

(See attached map)

SPEAKER

Paul Rogers, P.Eng., Ph.D.

Associate Professor

Department of Mechanical & Manufacturing Engineering
University of Calgary

TOPIC

Input Control via Delayed Order Release and Judicious Order Rejection: Results from Simple Queuing Models

Abstract:

The topic of "workload control" (or input control) in manufacturing systems has been growing in importance with manufacturers trying to achieve both high levels of productivity from their resources and high levels of responsiveness to customer demands. In make-to-order production environments facing uncertain demand, it is especially challenging to meet both responsiveness requirements (low flow times and good on-time delivery performance) and efficiency requirements (high utilization of production resources). Two critical aspects of workload control in this make-to-order context include the making of decisions concerning which customer orders should be accepted and when should accepted orders be released to the shop floor. In cases where demand is highly variable, accepting all orders can cause due date performance to deteriorate to unacceptable levels, so the ability to judiciously reject customer orders represents one way of keeping due date performance acceptable (hopefully without having to reject too many orders). Although there has been substantial discrete-event simulation work reporting on the performance of various alternative "acceptance/rejection" policies and "order release" policies, few general conclusions can be drawn from this work, and little real insight appears to have been gained.

This presentation will focus on work that has been completed at the University of Calgary on the performance of optimal order rejection and delayed order release policies for the well-known M/M/1 queuing system (exponentially distributed job interarrival times and exponentially distributed service times for a single server), when there are linear earliness and tardiness penalties for jobs not completed exactly on their due time. Three different policies will be described during the presentation, the first which involves just a delayed order release mechanism, the second which involves just an order rejection mechanism, and the third which involves both mechanisms in concert. Results presented will include the determination of optimal control parameters for the three policies and how the optimal policies perform under a broad range of conditions. The models and results described in the presentation were developed by the presenter and Mr. Yannai Zev Romer Segal during the latter's research towards the M.Sc. degree at the University of Calgary under the supervision of the presenter. For those seeking more detail than can be covered in a short presentation, full details on the three models and their results can be found in Mr. Segal's M.Sc. thesis, available in the University of Calgary library.

About the Speaker

PAUL ROGERS is an Associate Professor in the Department of Mechanical and Manufacturing Engineering at the University of Calgary. He holds Ph.D. and M.Eng. degrees from Cambridge University in England where he was involved in industry-funded research within the Manufacturing Engineering Group on the design and operation of flexible machining systems. Before joining the University of Calgary in 1991, he spent two years as a visiting professor of Industrial Engineering at Purdue University in the USA. His current research and teaching interests include production planning and control systems, manufacturing strategy, distributed and dynamic scheduling, and models for the design, analysis and control of manufacturing systems. He is a Professional Engineer registered with the Association of Professional Engineers, Geologists, and Geophysicists of Alberta (APEGGA), a member of IIE, APICS, and INFORMS, and serves on the Editorial Board of the International Journal of Computer Integrated Manufacturing. He can be contacted by email at <rogers@ucalgary.ca>.