Research Of Component Software Reliability Optimization

When Jeliski-Moranda presented the first model of software reliability in the early days of 70's,the research about software reliability is the highlight of software engineering all the while。By recent investigation,software reliability and software reliability engineering became gradually maturity,and the most important aspect is the research about component software。Because we can not exactly measure reliability of component software,how to give the precision reliability estimation of component software is the main problem。The data source used to estimate vary,so the uncertainty of component software reliability must exist,and there are estimation variance in component software reliability。Thus,it is great need to consider the factor of estimation variance to develop truly useful reliability estimation models and reliability optimization of component software。There have two innovations in the thesis: RPP-c strategy and the use of Cross-Entropy to solve the problem of minimizing estimation variance of component software.The traditional RPP strategy of component software reliability optimization does not consider the cost of the additional testing required to decrease component-estimate variance。So we put forward a modified RPP strategy:RPP-c strategy。We should not only think over how to decrease the estimation variance of component software with higher RPPI,but also need to calculate the interrelated supererogatory test cost。The RPPI value and the test cost determine the ultimately solution together,namely we ought to choose these component software which can contribute much to the whole system reliability estimation under much lower cost level。In order to reduce the influence of reliability estimation variance,we must consider the problem about minimizing estimation variance。It is a celerity,utility and effective method to use Cross-Entropy to deal with reliability optimization。With theory of Important Sample(IS) and Cross-Entropy(CE),we bring forward the project to minimize estimation variance。At last,we give the CE algorithm and experiment result of component software optimization。...