Abstract
In this paper, we investigate some techniques for reliability prediction and assessment of fielded software. We first review how several existing software reliability growth models based on Non-homogeneous Poisson Processes (NHPPs) can be readily derived based on a unified theory for NHPP models. Furthermore, based on the unified theory, we can incorporate the concept of multiple change-points into software reliability modeling. Some models are proposed and discussed under both ideal and imperfect debugging conditions. A numerical example by using real software failure data is presented in detail and the result shows that the proposed models can provide fairly good capability to predict software operational reliability.