Software reliability growth models incorporating fault dependency with various debugging time lags

Software reliability is defined as the probability of failure-free software operation for a specified period of time in a specified environment. Over the past 30 years, many software reliability growth models (SRGMs) have been proposed and most SRGMs assume that detected faults are immediately corrected. Actually, this assumption may not be realistic in practice. In this paper, we first give a review of fault detection and correction processes in software reliability modeling. Furthermore, we will show how several existing SRGMs based on NHPP models can be derived by applying the time-dependent delay function. On the other hand, it is generally observed that mutually independent software faults are on different program paths. Sometimes mutually dependent faults can be removed if and only if the leading faults were removed. Therefore, here we incorporate the ideas of fault dependency and time-dependent delay function into software reliability growth modeling. Some new SRGMs are proposed and several numerical examples are included to illustrate the results. Experimental results show that the proposed framework to incorporate both fault dependency and time-dependent delay function for SRGMs has a fairly accurate prediction capability.