A study of the multi-stage flowshop scheduling problem with alternative operation assignments

In small-item large lot production, a single person had only single processing to do. A recent tendency of the production system is the multi-item small lot production. In this type of production system, one work person needs skills that are adaptable to multi-item articles. As the single work person needs more than one skill, one processing operation which comprises a job has come to be handled by several work persons. From the viewpoint of a job, one elementary operation has come to be processed by several alternative operation assignments. We discuss the problem of how to minimize the total elapsed time from the start up time to the completion of a job. In order to solve this problem, we analyze it theoretically under a simpler condition, then we propose an approximation algorithm based on the theoretical analysis applicable to a more general problem. (C) 2002 IMACS. Published by Elsevier Science B.V. All rights reserved.