Abstract: On Modelling Preventive Replacements of Randomly Deteriorating Systems

In this paper we describe the preventive replacement model for randomly deteriorating sing le unit systems and illustrate some of the main difficulties met in practical situations. We discuss in more details two special cases: a replacement model with a mixture of actions at f ailure and a nonparametric replacement model based on the bootstrap methodology. It is seen that although the general replacement problem might be relatively simply formulated , obtaining the objective function as much explicitly as possible is not always a trivial mat ter and finding a numerically efficient algorithm to obtain the optimal solution is not always easy.