Point Process Based Maintenance Modeling for Repairable Systems: A Review

In this article, the intricacies involved in the ma intenance of the industrial repairable systems are analyzed. Based on the practical requirement, the mathematical models for repairable system maintenance which are using p oint process theory are listed and reviewed. The available estim ation, inference and prediction methodologies are a lso listed. The future issues which are to be addressed in the math ematical modeling for maintenance are also pointed out. capable of high speed and continual production capa city. In this context, the maintenance activities f or these complex industrial equipments or systems not only e nsure the timely delivery for profits in the busine ss, preventing environmental hazards and safety hazards. The syst em which undergoes the aforementioned maintenance activities are referred in technical literature as maintained systems or repairable systems. These repairable sys tems are defined as, a system which after failing to perform one or more of its function satisfactorily, can be restore d to fully satisfactory performance by any method other than r eplacement of the entire system , Ascher and Feingo ld (1). Large number of technical papers and many books are published in the field of maintenance modeling for repairable system. Most of these developed models actually never applied in practical maintenance activities. Asc her and Feingold (1), Scarf (2) states that still the maint enance policy managers and engineers takes the deci sions heuristically using their engineering back ground a nd common sense. This is because of the unrealistic assumptions of the theoretical models which do not suit the pra ctical realistic situation of the industries. As st ated by Guo et al. (3) the models developed for maintenance should be efficient, reflective of the situation and good app roximating tools. And hence these mathematical models should i ncorporate the elements of the environment in which operation and maintenance takes place, failure causes etc. A s per Kumar and Liyanage (5) if one could formulate a concise statement on the role of maintenance, it is primari ly to reduce business risks on the continuous basis in cost - effective manner. All these statements in research literature leads to the development of maintenance models which can be used to plan for the spares, resources and r eplacement strategies which in turn help to reduce the cost of the production activities, and also to reduce safety an d environmental hazards.