Replacement problems for a cold standby repairable system.

In this paper, a cold standby repairable system consisting of two identical components and one repairman is studied. Assume that each component after repair is not “as good as new”, by using a geometric process, we consider two kinds of repair replacement policy, one based on the working age T of component 1 under which the system is replaced when the working age of component 1 reaches T , and the other based on the failure number N of component 1 under which the system is replaced when the failure number of component 1 reaches N . Our problem is to choose optimal replacement policies T * and N * respectively such that the long-run average cost per unit time of the system is minimized. And we can prove under some mild conditions that the optimal policy N * is better than the optimal policy T *. Finally, a numerical example for policy N is given. [ABSTRACT FROM AUTHOR]