Research Of The Assessment Approach For Complex Software Reliability

With the rapid development of information and technology,software systems,as the carrier of all kinds of functions realized by computer,have penetrated into every field of people's production and life and played a very important role.Some safety critical areas,such as bank,transportation,aerospace,nuclear power and so on,have pretty high requirements for the reliable operation of software systems.As one of the important attributes of software quality,the quantitative analysis and evaluation of software reliability has become a research hotspot in related fields.In the past 40 years,researchers have proposed hundreds of models to evaluate the reliability of software.However,as the needs of users become more and more complex and software operating patterns move towards distributed,software systems also get more and more complex.In this case,the traditional single software reliability model evaluation method cannot meet the reliability evaluation requirements for complex software systems.In addition,when the minor modifications are made for a complex software system developed on components,the existing software reliability evaluation methods need to recalculate the reliability for all components of the software system.It brings the problem of low evaluation efficiency.Therefore,this dissertation takes the reliability evaluation of the complex software system as the research object,and studies how to improve the accuracy and efficiency of the reliability evaluation of this kind of system.The main work of this dissertation is as follows:1.In view of the fact that the traditional single model cannot meet the needs of complex software reliability evaluation,this dissertation formally defines the features of software reliability models,and then presents the unified method of constructing the basic set of software reliability model with the help of the feature matrix obtained from feature quantization.2.According to the characteristics of software reliability evaluation,the traditional fitness function and mountain-climbing operation of genetic algorithm are improved and used to solve the weight value of the base models.Then a software reliability evaluation method based on weighted combinational basis models is presented.Through the comparison of different methods on the same data set,the results show that the proposed method in this dissertation has a significant improvement in global evaluation accuracy and evaluation efficiency.3.On the basis of studying the internal structure of the component software system and its relationship,a recursive software reliability calculation method is presented by defining the hierarchical component software structure model.With the help of the identification of the affected areas because of the modification of the component software system,the method can only recalculate the reliability of such areas.Therefore,the purpose of reducing the calculation workload of reevaluating reliability and improving the evaluation efficiency is realized.On the one hand,the research work of this dissertation can effectively improve the evaluation accuracy of complex software system.On the other hand,it is helpful to improve the efficiency of reliability reevaluation of complex software system for design modifications and effectively reduce the cost from all aspects of the reevaluation.While enriching the existing software reliability evaluation theory and method system,it is helpful to evaluate the reliability of complex software system better so that it can reduce all kinds of losses caused by its failure.Therefore,it has better social and economic benefits.