COMPARATIVE STUDY ON THE COST ANALYSIS OF SOFTWARE DEVELOPMENT MODEL APPLICABLE TO SYSTEM SOLUTIONS BASED ON GAMMA FAMILY DISTRIBUTION

In this study, we analyzed and predicted the software development cost applicable to system solutions based on the lifetime distribution of the Gamma family (Erlang and Log-Logistic) which is widely utilized in the field of software reliability testing together with the Goel-Okumoto basic model. Also, the optimal development cost model was suggested through these analysis results. For this, software failure time data was used, the parametric calculation was applied to the maximum likelihood estimation (MLE) method, and nonlinear equations were solved by a numerical method (bisection method). As a result, First, the cost curve shape of all proposed models decreased in the initial stage but continuously increased in the later stage because the probability of finding the remaining defects is gradually lowered. Second, if the cost of eliminating a single defect found in the testing process increased, the development cost also increased, but the release time did not change. Third, if the defect correction cost discovered by the operator during the operation stage increased, the development cost at the time of release is increased, and the release time is also delayed. Also, it was confirmed that the Erlang distribution model showed the best performance because it has a lower software development cost and a faster release time point than the proposed other models. Through this study, the software development cost of the Gamma family distribution without the existing research examples was newly analyzed. Therefore, we were able to present software developers with the necessary information to predict the economic software development cost and the optimal release time.