Towards the Quantitative Evaluation of Phased Maintenance Procedures Using Non-Markovian Regenerative Analysis

The concept of Phased Mission Systems (PMS) can be used to describe maintenance procedures made of sequential actions that use a set of resources and may severely affect them, for instance operations that require outage of hardware and/or software components to recover from a failure or to perform upgrades, tests, and configuration changes. We propose an approach for modeling and evaluation of this class of maintenance procedures, notably addressing the case of actions with non-exponential and firmly bounded duration. This yields stochastic models that underlie a Markov Regenerative Process (MRP) with multiple concurrent timed events having a general (GEN) distribution over a bounded support, which can be effectively analyzed through the method of stochastic state classes. The approach allows evaluation of transient availability measures, which can be exploited to support the selection of a rejuvenation plan of system resources and the choice among different feasible orderings of actions. The experiments were performed through a new release of the Oris tool based on the Sirio framework.