Application research of a new neighbourhood structure with adaptive genetic algorithm for job shop scheduling problem

The job shop scheduling problem (JSSP) is to find the optimal jobs sequence to optimise one or more performance indicators and makespan is the most common optimisation target. In solving NP-hard problems such as JSSPs by genetic algorithm (GA), trapping in local extremum, low search efficiency and instability are often encountered, especially unable to find the optimisation direction. To restrain this condition, a new neighbourhood structure with adaptive GA was put forward. The crossover probability (Pc) and mutation probability (Pm) can be adjusted in nonlinear and adaptive based on the dispersion of the fitness of population in the evolution. The idle time before critical operations can be made full use of through the multi-operations combination and adjustment. To research the performance of the proposed method in solving JSSPs, a detailed application scheme was given out for the process of it. In the solving scheme, the chromosome active decoding algorithm with the objective function of maximum makespan was proposed. From the results of testing of 28 JSSP benchmark instances in 3 adaptive strategies and 3 neighbourhood strategies, the new neighbourhood structure with adaptive GA has been significant improvement in solution accuracy and convergence efficiency.