Availability and reliability estimation for a system undergoing minimal, perfect and failed rejuvenation

In this paper, a software rejuvenation model is presented in which two different rejuvenation actions are considered, perfect and minimal. The concept of a failed rejuvenation action which leads the system to failure is also introduced. The presented model is studied under a Continuous Time Markov Chain (CTMC) framework and a maximum likelihood estimator of the generator matrix is presented. Based on this, estimators for instantaneous availability and reliability function are also presented. Moreover, the behavior of the above estimators is studied under various rejuvenation policies. A numerical example based on simulation results is finally presented.