This paper proposes a mathematical model of an optimal periodic schedule revision policy for jobshop scheduling where we detect delays of tasks and perform a periodic schedule revision at
iT/M (
i= 1, 2, …,
M) for a schedule period
T. We first overview the jobshop scheduling and then investigate the property of schedule delays. The long-run average cost per unit time of the schedule revision policy is, secondly, formulated under the assumption that the number
N (t) of delayed tasks occurring over (0,
t] follows a non-homogeneous Poisson process with mean value function
H (t) . It is shown that there always exists a finite frequency
M* minimizing the long-run average cost. Through computational experiments, finally, we discuss the characteristics of the proposed policy and its applicability to jobshop scheduling problems.
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