Record Detail

Flexible job shop scheduling in uncertain environ-ments plays an important part in real-world manufacturing systems. With the aim of capturing the uncertain and multi-objective nature of flexible job shop scheduling, a mathe-matical model for the multi-objective stochastic flexible job shop scheduling problem (MOSFJSSP) is constructed, where three objectives of make-span, maximal machine workload,and robustness to uncertainties are considered simultane-ously under a variety of practical constraints. Two new scenario-based robustness measures are defined based on sta-tistical tools. To solve MOSFJSSP appropriately, a modified multi-objective evolutionary algorithm based on decomposi-tion (m-MOEA/D) is developed for robust scheduling. The
novelty of our approach is that it adopts a new subprob-lem update method which exploits the global information, allows the elitists kept in an archive to participate in the child generation, employs a subproblem selection and suspension strategy to focus more computational efforts on promis-
ing subproblems, and incorporates problem-specific genetic operators for variation. Extensive experimental results on 18 problem instances, including 8 total flexible and 10 partial flexible instances, show that the two new robustness mea- sures are more effective than the existing scenario-based
measures, in improving the schedule robustness to uncertain- ties and maintaining a small variance of disrupted objective values. Compared to the state-of-the-art multi-objective opti- mization evolutionary algorithms (MOEAs), our proposed m-MOEA/D-based robust scheduling approach achieves a
much better convergence performance. Different trade-offs among the three objectives are also analyzed.