Software Reliability Modelling Considering both Testing Effort and Testing Coverage

Considering testing effort function (TEF) or testing coverage function (TCF) in the non-homogeneous Poisson process (NHPP) software reliability modeling can further improve the fitting and prediction performance of the NHPP software reliability growth models (SRGMs). Thus this paper discusses how to integrate both TEF and TCF into the traditional NHPP software reliability modeling process to capture the integrated effect of testing effort and testing coverage on reliability estimation. First we present a new TEF, i.e. the inflected S-shaped TEF (IS-TEF) for describing the S-shaped varying trend of the testing-effort increasing rate more accurately. Meanwhile, a new NHPP SRGM (named IS-SRGM) which considers the IS-TEF is proposed. Then a comprehensive modeling framework for incorporating the TEF and TCF is proposed. Recur to this framework, a new NHPP SRGM (named IS-LO-SRGM) with both the IS-TEF and logistic TCF (LO-TCF) is proposed. Finally, two case studies for validating the effectiveness of the IS-TEF and the IS-LO-SRGM in terms of fitting results are presented. The results show that: the comprehensive modeling framework to incorporate the TEF and the TCF in NHPP SRGMs achieves a substantial improvement compared with the NHPP SRGMs which only consider the TEF or the TCF.