A time window based approach for job shop scheduling

A time window based approach is developed for job shop scheduling problems to minimize the weighted earliness and tardiness cost. With the time windows provided by Lagrangian relaxation within which parts are processed to minimize the cost and an effective algorithm to find a feasible schedule within or approximately within the windows, the approach can generate schedules better than those generated by the Lagrangian relaxation approach for large problems in a similar computation time. This demonstrates that our approach can be used to solve practical scheduling problems with an improved performance.