抄録
Discrete time Markov maintenance models are coupled with the theory of control of queues. Each system has an operating machine, spare machines and a repair facility. A decision maker has the option of opening or closing the repair shop when there are machines waiting for repair service, as well as the option of repairing or leaving an operating machine. A two-dimensional control limit policy is defined, and sufficient conditions for the optimality of a two-dimensional control limit policy are obtained for each model.
