Integrating rush orders into existent schedules for a complex job shop problem

This paper investigates the problem of inserting new rush orders into a current schedule of a real world job shop floor. Effective rescheduling methods must achieve reasonable levels of performance, measured according to a certain cost function, while preserving the stability of the shop floor, i.e. introducing as few changes as possible to the current schedule. This paper proposes new and effective match-up strategies which modify only a part of the schedule in order to accommodate the arriving jobs. The proposed strategies are compared with other rescheduling methods such as “right shift” and “insertion in the end”, which are optimal with respect to stability but poor with respect to performance, and with “total rescheduling” which is optimal with respect to performance but poor with respect to stability. Our results and statistical analysis reveal that the match-up strategies are comparable to the “right shift” and “insertion in the end” with respect to stability and as good as “total rescheduling” with respect to performance.