DISPATCHING RULES FOR JOB SHOP PROBLEMS

Abstract

Makespan or minimum total completion time is used as a measure to evaluate between dispatching rules under consideration. Dispatching rules has been extensively applied to the scheduling problems in job shop manufacturing. They are procedures designed to provide good solutions to problems in short time. The aim of this study is to evaluate the performance of some dispatching rules when different number of jobs and different number of machines based on minimum total completion time (makespan C_max). A simulation study has been made to evaluate the performance for some dispatching rules from fourteen dispatching rules which used in this study, the results has been shown that Shortest Processing Time (SPT) is the efficient method when the number of machines is 2 and number of jobs are (10, 30, and 100), Most Operations Remaining (MOPR) is the efficient method when the number of machines is 10 and number of jobs are (10, 30, and 100) and Most Work Remaining (MWKR) is the efficient method when the number of machines is 20 and number of jobs are (10, 30, and 100).