Optimal assignment of priorities for the machine interference problems

This paper investigates multiple machine repair problems with one repairman. Each machine is subject to two modes of failure, major and minor. The machines are identical, with times to repair and the times to failure assumed to be negative exponentially distributed. In this paper we consider the problem: when there are i and j failed machines in modes 1 and 2, respectively, which mode of failure should be selected for repair? A profit model is developed and then, to achieve the optimal profit, we derive the optimal repair policy for the single repairman. In addition, we describe a procedure to determine the optimal number of machines which should be assigned to a repairman. Numerical examples are provided in which the system characteristics are evaluated and profits are analyzed.