基于贝叶斯理论的软件可靠性评估方法研究

Resarch Of Software Reliability Estimation Method Based on Bayes Theory

本文以贝叶斯统计理论为依据,建立了基于输入域的测试过程的形式化描述,在此基础上确定了测试分布的总体信息;按照贝叶斯理论,要对软件可靠性进行估计,需要定义软件可靠性的先验分布,该先验分布可以利用贝叶斯假设或共辘原理进行定义。分析发现,在软件顺序测试过程中,采用这两种策略所得到的先验分布是一致的,这从另一种角度印证了先验分布选取的正确性。根据贝叶斯定理,利用先验分布和总体分布,可以得到待估计变量的后验分布,然后根据测试数据可以对可靠性进行估计。

By the analysis of the random testing procedure, we can see that a Bernoulli distribution can be used to descdbe the random testing procedure. The general information that is used by the Bayesian method is depicted by this distribution. Then the selection method about the pdor probability density function and the parameter used by this function is analyzed. It will help to define the pdor information needed by the Bayesian method According to the general information, the pdor information and the testing information, the post probability density function can be constructed, that can be used to calculate the correctness probability of a program. At last, the program reliability estimation method is provided.