Optimal control of a removable and non-reliable server in an infinite and a finite M/H-2/l queueing system

This paper deals with a single removable and non-reliable server in both an infinite and a finite queueing system with Poisson arrivals and two-type h yper-exponential distribution for the service times. The server may be turn ed on at arrival epochs or off at service completion epochs. Breakdown and repair times of the server are assumed to follow a negative exponential dis tribution. Conditions for a stable queueing system, that is steady-state, a re provided. Cost models for both system capacities are respectively develo ped to determine the optimal operating policy numerically at minimum cost. This paper provides the minimum expected cost and the optimal operating pol icy based on assumed numerical values given to the system parameters, as we ll as to the cost elements. Sensitivity analysis is also investigated. (C) 1999 Elsevier Science Inc. All rights reserved.