COMPARATIVE PERFORMANCE ANALYSIS OF PRIORITY RULES IN A CONSTRAINED FLOW-SHOP WITH MULTIPLE PROCESSORS ENVIRONMENT

Scheduling in a flow shop with multiple processors (FSMP) involves the sequencing of n jobs in a flow shop, where two or more identical proc essors are allowable at a machine stage. The constrained flow shop wit h multiple processors problem (CFSMP) considered in this study is a sp ecial case of the FSMP problem, in which the total number of jobs that can concurrently exist in the system is bounded by a prespecified num ber. A simulation experiment was performed to investigate the performa nce of six priority rules in the CFSMP environment for three performan ce measures namely makespan, mean flow time, and maximum flow time. A dynamic simulation model of the constrained flow shop with multiple pr ocessors environment was developed in which the queuing priorities at each machine stage were established dynamically. The results of the si mulation study indicated that the shortest processing time first dispa tching procedure (SPT) yielded superior performance for the makespan a nd mean flow time criteria. However, for the maximum flow time criteri on, clear superiority of a particular dispatching procedure was not es tablished.