Cyclic Job Shop Problem with varying processing times

Abstract : In this paper, we consider a cyclic job shop problem where a subset of tasks have varying processing times. The minimum processing times and maximum processing times of these tasks are known. We propose a branch and bound method that finds the schedule which minimizes the mean cycle time with respect to variations. We show that the evaluation of a schedule can be considered as a volume calculus of some polytopes. Indeed, for each schedule we can associate a set of polytopes whose volumes provide information on the variation effect on the considered schedule.