Research On NHPP Software Reliability Growth Models Considering Testing And Operational Difference

As the software products go into various military and civilian equipments along with computers, people pay more and more attention to the issue of software quality. Software reliability is the most important content among the quality attributes of software, which quantitatively describes the failures occurring during the developing and use of software. The software reliability growth models (SRGMs) are the main methods for evaluating and predicting software reliability. Among various SRGMs, the SRGM of the type of the non-homogeneous Poisson process (NHPP) is very important, which absorbs most researches and are applied widely. Such a model generally assumes that the testing environment and the operating environment of software are same, namely, the failure data of software obtained in the testing environment can predict the reliability of software in the operating environment. To improve the accuracy of the evaluation and predicting of software reliability, this paper researches on the influence of the difference of profiles on the evaluation of software reliability by starting with the difference between the operating profile and the testing profile.Firstly, This paper discusses the difference between the testing profile and the operating profile, obtains the testing ratio of coverage in the testing phase and the testing ratio of coverage in the operating phase according to practically measured data, thereby describing the difference between the testing profile and the operating profile quantitatively with the testing ratio of coverage. Furthermore, this paper provides several forms of failure ratio in the operating phase taking the difference between the testing profile and the operating profile into account according to the concepts of the testing reliability and the operating reliability, then analyzes theoretically the difference between the testing reliability and the operating reliability based on the changing trends that the failure of decreasing and first increasing and the decreasing of the failure ratio, and makes a research on the influence of the two types of reliability on the software releasing time.Most of the SRGMs assume that software failures follow a same distribution during software testing process. In practice, software failures are often affected by various factors, such as the operating environment, the testing method, the resource allocation, and so on, thus it is impossible for software failures to follow a same distribution. This is the issue of changing point. The essence of the technique of changing points is to perform fit on the failure data according the failure trend of...