A hybrid evolutionary algorithm based on new neighborhood structure for steelmaking–refining–continuous casting scheduling problems with controllable processing times
摘要
Iron and steel industry is a significant basic industry, where steelmaking–refining–continuous casting (SRCC) is a bottleneck. Efficient SRCC schedules can enhance the iron and steel production productivity greatly. SRCC scheduling problems are important and challenging industrial scheduling problems, as well as well-known nondeterministic polynomial time-hard problems. In the realistic SRCC process, the last production stage’s processing times are controllable, and the corresponding scheduling problems are named SRCC scheduling problems with controllable processing times (CPTs). To deal with the SRCC scheduling problems with CPTs efficiently, a new neighborhood structure (named restricted multiswap) and a new decoding method based on domain knowledge, and then a hybrid evolutionary algorithm (HEA) are proposed. The proposed HEA integrates several distinguished features: the aforementioned neighborhood structure and decoding method, local search, biased probability-guided crossover, and two diversification strategies including perturbation and mutation. The HEA achieves the lowest average relative percentage increase (RPI) in comparison with seven state-of-the-art scheduling algorithms, with the average RPI of 0.02%, 0.05%, 0.09% under time limits of 10, 20, and 30 s, respectively.