Introducing co-evolution and sub-evolution processes into genetic algorithm for job-shop scheduling

In our recent research, we gave results of a comparative study of the effects of using several kinds of scheduling evaluation criteria as the fitness function of a genetic algorithm for job-shop scheduling. From these results, we found that the idle time criterion can sometimes provide a good makespan-minimizing schedule for a job-shop scheduling problem. In this paper, according to the above results, we introduce a coevolution process in which both makespan and idle time schedule criteria are employed as the fitness functions in the operation-based genetic algorithm for job-shop scheduling. Additionally, to provide high diversity for the chromosome population, we introduce a sub-evolution process in which the total job waiting time schedule criterion is used as the fitness function in the proposed genetic algorithm.