Bounding steady-state availability models with group repair and phase typerepair distributions

We propose an algorithm to obtain bounds for the steady-state availability using Markov models in which only a small portion of the state space is gen erated. The algorithm is applicable to models with group repair and phase t ype repair distributions and involves the solution of only four linear syst ems of the size of the generated state space, independently on the number o f "return" states. Numerical examples are presented to illustrate the algor ithm and compare it with a previous bounding algorithm. (C) 1999 Elsevier S cience B.V. All rights reserved.