NHPP-based software reliability model considering testing effort and multivariate fault detection rate

In recent decades, many software reliability growth models (SRGMs) have been proposed for the engineers and testers in measuring the software reliability precisely. Most of them is established based on the non-homogeneous Poisson process (NHPP), and it is proved that the prediction accuracy of such models could be improved by adding the describing of characterization of testing effort. However, some research work indicates that the fault detection rate (FDR) is another key factor affects final software quality. Most early NHPP-based models deal with the FDR as constant or piecewise function, which does not fit the different testing stages well. Thus, this paper first incorporates a multivariate function of FDR, which is bathtub-shaped, into the NHPP-based SRGMs considering testing effort in order to further improve performance. A new model framework is proposed, and a stepwise method is used to apply the framework with real data sets to find the optimal model. Experimental studies show that the obtained new model can provide better performance of fitting and prediction compared with other traditional SRGMs.