Optimisation analysis of the F-policy retrial machine repair problem with working breakdowns

This paper deals with a retrial machine repair problem with working breakdowns that combines F-policy and exponentially start-up time before allowing failed machines to join the system. A server is subject to working breakdowns when at least one failed machine is in the system. Using the matrix-analytic method, we develop the steady-state probabilities of the number of failed machines in an orbit. Closed-form expressions of major system performance characteristics and the total expected cost function are presented. A particle swarm optimisation algorithm is implemented to determine the optimal management F-policy and joint optimal values for fast and slow service rates simultaneously at minimum cost. A sensitivity analysis with numerical illustrations is as well presented.