On-off scheduling

FMS scheduling has been in the past decade an inspirational subject and one could easily find a vast amount of literature citing different approaches and methods in solving this NP-hard problem. The difficulty of FMS scheduling arises from its flexibility. This flexibility can be in terms of machine routings and processing. On the one hand, flexibility offers more choices, on the other hand, the scheduler has the difficult task in selecting the “best” choice. Often the best solution may not be optimal but good due to real time constraints. However, in the scheduling literature there are a number of authors that advocate predictive scheduling as they argue that flexibility could be explored more thoroughly. The aim of this article is to propose an integrated system for the purpose of scheduling-an “on-off” (on-line and off-line) scheduling system. This system combines features of real-time and predictive scheduling with a simulator module. The authors examine the options available to enhance the efficiency of solution-finding for scheduling problem in these two domains of scheduling, in particular, a linkage is drawn between predictive and real-time scheduling