An Efficient Proactive Reactive Scheduling Approach to Hedge against Shop Floor Disturbances

We consider the single machine scheduling problem with dynamic job arrival and total weighted tardiness and makespan as objective functions. The machine is subject to disruptions related to late raw material arrival and machine breakdowns. We propose a proactive-reactive approach to deal with possible perturbations. In the proactive phase, instead of providing only one schedule to the decision maker, we present a set of predictive schedules. This set is characterized by a partial order of jobs and a type of associated schedules, here semi-active schedules. This allows to dispose of some flexibility in job sequencing and flexibility in time that can be used on-line by the reactive algorithm to hedge against unforeseen disruptions. We conduct computational experiments which prove that our approach outperforms a predictive reactive approach particularly for disruptions with low to medium amplitude.