SCHEDULING ARRIVALS TO A PRODUCTION SYSTEM IN A FUZZY ENVIRONMENT

A frequently encountered scheduling problem is to determine a material and job ready time while simultaneously finding a production sequence given customer-specified due dates. Often the production times and du e dates are vague. This paper presents an investigation of scheduling ready times for a set of jobs with fuzzy service times and due dates. The ready time is constrained in that the possibility that a job is la te must not exceed a predefined value. The objective in such an instan ce is to maximize the ready time without violating these constraints. The steps necessary to determine the maximum ready time and cases in w hich this effort may be significantly reduced are presented for single machine and flow shop production systems. Finally, a branch and bound technique is developed for cases in which the optimal job sequence ca nnot be determined a priori.