A Heuristic Method for Minimizing Makespan in M-Stage Hybrid Flowshop

This paper deals with a scheduling problem to minimize makespan in m-stage hybrid flowshop with unrelated parallel-machines at least one stage. Since the problem is known to be NP-hard, a two-phase heuristic algorithm is proposed to obtain a near-optimum schedule efficiently. In the first phase of the proposed algorithm, some promising schedules with an identical job-sequence to all stages are generated by applying NEH algorithm in various ways, and then search better schedules by applying some heuristic job-moving strategies to these schedules in the second phase. Numerical experiments are implemented to demonstrate that the proposed method can provide a near-optimum schedule within a reasonable computation time.