Single-machine scheduling with deteriorating jobs and aging effects under an optional maintenance activity consideration

This article studies a single-machine scheduling with deteriorating jobs and aging effects under an optional maintenance activity. We assume that after maintenance activity, the machine will revert to its initial condition and the aging effects will start anew. Moreover, due to the restriction of budget of maintenance, the limitation of the maintenance frequency on the machine is assumed to be known in advance. The optional maintenance activity of this study means that the starting time of the maintenance activity is unknown in advance. It can be scheduled immediately after the processing of any job that has been completed. Therefore, the planner must to make decision on whether or when to schedule the maintenance activity during the scheduling horizon to optimal the performance measures. The objective is to minimize the makespan. We first show that the addressed problem is NP-hard in the strong sense. Then a fully polynomial-time approximation scheme (FPTAS) for the proposed problem is presented.