Abstract
This paper deals with job shop scheduling with alternative machines. Genetic algorithm incorporating heuristic rules for job selection and machine selection is used for searching schedules to minimize average tardiness of jobs. Six rules for job selection and five rules for machine selection are tested. Numerical experiments show that the combination of SL/RPN+SPT rule for job selection and (WINQ+RPT+PT)×PT rule for machine selection gives the best performance. Although applying genetic algorithm improves performance, the method applying genetic algorithm only for machine selection outperformed the method applying genetic algorithm both for job selection and machine selection.
