Abstract
There is a general agreement that open source software (OSS) plays an increasingly critical role in the modern society. In the past, some research findings showed that the Pareto principle, the traditionally-used Pareto distribution (PD) and the Weibull distribution (WD) models would be able to describe the distribution of software fault; a Pareto principle related 2-parameter generalized Pareto distribution (2-GPD), however, could be more useful to model the distribution of software faults in our previous study. This paper studies a modification of the 2-GPD model called the 2-parameter generalized single change-point Pareto distribution (SCP-2GPD) model, and the selection of change-point is highly pertinent to the Pareto principle. The research focuses on modeling the distribution of OSS faults, and some mathematical properties of the SCP-2GPD model are presented. Sources of data based on Apache and Mozilla found in bug database of OSS called Bugzilla are performed in order to ascertain the prediction capability of fault distribution for the SCP-2GPD model. Compared with other fault distribution models, the findings suggest that the proposed SCP-2GPD model has a fairly accurate prediction capability of fault distribution of OSS. These findings have implications for analyzing the fault distribution of real-life-various OSS.