Capability of cumulative delay based reactive scheduling for job shops with machine breakdowns

This paper proposes a new when-to-schedule policy in reactive scheduling, which considers timing of schedule revision based on the concept of a control limit policy. Under the proposed policy, schedule revision is carried out based on a cumulative task delay which can be a measure to determine suitable timing of schedule revision. Some computational experiments demonstrate the effectiveness of the proposed policy by applying it to job shop problems with machine breakdowns, where we minimize maximum tardiness as well as scheduling frequency. It is also shown that the proposed policy with even low scheduling frequency can outperform an event-driven rescheduling approach, which is one of the major effective reactive scheduling methods.