A hybrid approach for single-machine tardiness problems with sequence-dependent setup times

Scheduling problems in real systems often require sequence–dependent setup times. The topic of sequence–dependent setup times has not been addressed adequately, and improved competitiveness is thus not achieved. This study proposes a hybrid approach that takes advantage of simulated annealing (SA) and tabu search (TS) to solve single–machine tardiness problems with sequence–dependent setup times. To verify the proposed approach, experiments were conducted on benchmark problem sets that included both the weighted and un–weighted tardiness problems. The results show that the performance of the hybrid approach is superior to that of the SA, genetic algorithm, TS and ant colony optimization approaches, and is comparable with the Tabu–VNS approach. And the proposed approach found new upper bound values for many benchmark problems with an acceptable computational time.