A non-homogeneous Markov software reliability model with imperfect repair

This paper reviews existing non-homogeneous Poisson process (NHPP) software reliability models and their limitations, and proposes a more powerful non-homogeneous Markov model for the fault detection/removal problem. In addition, this non-homogeneous Markov model allows for the possibility of a finite time to repair a fault and for imperfections in the repair process. The proposed scheme provides the basis for decision making both during the testing and the operational phase of the software product. Software behavior in the operational phase and the development test phase are related and the release time formulae are derived. Illustrations of the proposed model are provided.