摘要
This paper focuses on the parcel hub scheduling problem with shortcuts (PHSPwS), which is a critical inbound scheduling problem in parcel delivery industries such as postal service. PHSPwS employs shortcuts to determine the unloading schedule of inbound trailers/trucks in the closed-loop sorting process to minimize total makespan. PHSPwS not only considers the unequal batch sizes and various arrival times of inbound trailers but most importantly, the alternative parcel routing caused by the existence of multiple shortcuts in the closed-loop sortation system. A non-linear mixed integer program model is first formulated to address this problem. Given the computational complexity of the developed model, this research further proposes an adaptive genetic algorithm (AGA) to solve PHSPwS effectively. In the proposed AGA, local search (LS) is adopted to avoid entrapment in the local optimal solution, whereas fuzzy logic control (FLC) is utilized to adjust the probability of crossover and mutation rates. Considering the changes in average fitness values of parents and offspring in two consecutive generations could enhance the searching capability of the proposed algorithm. Computational results show that AGA with LS and FLC performs the solution better and with more stability than the other algorithms.