Flow-time performance of modified scheduling heuristics in a dynamic rescheduling environment

A generic, modular simulation model was constructed using the SLAM ZI discrete event modeling language to investigate the flowtime performance of a job shop. The findings of earlier research using conventional scheduling heuristics were confirmed and used to validate the design of revised AWINQ and MST heuristics. These heuristics were reformulated to take into account the state of the entire job shop at each rescheduling opportunity. Simulation results indicate that the revised heuristics perform better than the conventional SPT heuristic when job load is moderate. At high loads, the SPT rule was the preferred heuristic.