Research On Software Reliability And Software Optimal Release Problem

This paper mainly focus on the problems have relationship with software reliability, such as software reliability model, the cost of software development, optimal release problems and the testing method based on reliability prediction. The main research work of this paper may divide into two parts: The first part is about software reliability engineering, which include software reliability model, software reliability engineering in life cycle and the testing method on reliability prediction. The second part concerns software optimal release problems, which involve the cost of software development, the elementary models and extended models of software optimal release problems.The detail results are shown as follow:1. Upon the basis of comparison with various software reliability models, we present a software reliability model of real-time control software system. This model began with the reliability features of real-time control system, took all the possible factors that affect the whole reliability in consideration. The model is the combination of software reliability growth model based on NHPP, software-hardware system and semi-markov process. To compare with the similar models, our model can describe the real-time control software system, high-complexity firmware system and high-reliability system more exactly.2. The cost models of software development are researched by several ways. With the help of the existed results in the field of hardware reliability research area, we present a convert method with Gamma function to express the Rayleigh model of human resource allocation during software development process. Because the mathematical expressions of the software development process cost function are so complicated and Gamma function is usually applied in statistic theory, so we can deal with this kind of model easily. In order to get more elements to decide the software development cost, we use for references of the principle in non-cooperative game and the MCL model in economic field, than propose a market price model based on AHP analysis method. Use this model and the performance parameters of opponent's software product, one may make the decision about the price of our software products and the amount of the sales.Abstract3. Some software optimal release problems based on software reliability growth model are compared by many ways, the sensitivity of every model's parameter are also analyzed. Then we discuss the software optimal release problems that restricted by both software development cost and software reliability standard. Here some extended expressions of Goel-Okumoto model in terms of the actual application are given out. As an application of these models, with the help of software reliability growth model and software development cost function, we present an optimal release policy of commercial software product with warranty time.4. A reliability model of modular software is proposed. In this model, the total software reliability is expressed as function of every part's reliability. Use this model and software development cost function, we present an optimal release policy of multi-modular software. To compare with most of the similar models at present, our model has more precise structure, at the same time, with more simply mathematics expression and easy to use.5. We analysis the relationship between the testing process and software reliability evaluation. The two mainly testing methods, the debugging testing and operational testing are discussed in terms of their ability to affect the final release reliability. Using these results, we may get the optimal testing strategy in terms of the reliability evaluation to different software style, at the same time, we also find the appropriate testing method for different software and testing profile. As an application in engineering, a natural stopping rule to operational testing based on Bayesian method is proposed.