The Research On Reliability Analysis Using Petri Nets

With increasing scale of softwares, the service largely depends on applied softwares in our daily life. Some softwares now are applied to special fields, such as air industry, nuclear power technology, military industry, electron mechanism and banks. The failure of softwares will contribute to big loss of lives and money. The reliability of the software crys for being solved with the increasing scale and complexity.The work of software reliability analysis includes modeling software reliability and analysing software indexs, and the reliability model is very important. The present models mainly analyse with the failure tree, it can not describe the whole dynamic action, so it can not adapt to the quick changing environment and is restricted; Concerning the analyzing software indexs, most of calculating methods are used to analyse the failure of steady state, it makes us can not seize changing current of reliability; Besides, most of software failure are stochastic and interim ,then reliability model is formally a stochastic process, it makes time be much more important than defining dynamic logic.Firstly, the Stochastic Petri Net is applied to reliability model. It can help define dynamic action with relation between transition and time. Meanwhile, the detailed reliability model method is given with comparing concepts ,traits and relation between Stochastic Petri Net and software reliability; secondly, two methods are given in the paper to solve the state space explosion problem ; Thirdly, a method of calculating instantaneous reliability is introduced to analyse the simplified Stochastic Petri Net, it improves precision of model and can guide the reliability design; finally, the feasibility and validity are verified by the test.