The Research On Assessment Of Reliability Algorithms For Reliability Graph

At present, Complex computer systems are increasingly built for highly critical tasks. Failures of the systems may have severe consequences, we need know that the system whether the user satisfaction,this need assess the system.Dependability is a collective noun, including reliability, security and other attributes.This paper is based on the system reliability by the model of the system.The reliability of the system is based on thecomponent.To analysis reliability of a system, at present, many methods have been proposed, such as fault tree (FT), reliability block diagram (RBD), reliability graph (RG), Markov chain Monte Carlo simulation.Each method has its own advantages and disadvantages.If we only consider the ability of expression method, the existence of duplicate events of the fault tree is better than other modeling method.At present, the fault tree is repeated events is also widely used in reliability analysis of complex systems.The paper proposed a improvement model:N-reliability graph with general gates.Because of reliability graph with general gates (RGGG) has limited expression power.Based on RGGG, expanding to N-reliability graph with general. In N-RGGG, retaining the RGGG node attributes, the node with the logical relationship.There may be multiple arcs between nodes, the nodes can be reached by multiple components. Among them,. The node of N-RGGG showed the state, the line showed the component. System of extended N-RGGG closer to the real. System of extended N-RGGG closer to the reality of the.To solve different node reliability, the peper proposed a unified solution method.Evaluation N-reliability graph with general gates, giving a unified method for different logic node. Firstly, defining node function of different logical, A function definition is a logical expression logical expression, the unified simplified into conjunctive normal form, in the process of simplification, applied to the method of the probability,such as addition, subtraction, formula. Secondly,by acquiring segment assembly algorithm, a collection of components decomposition algorithm, a single component evaluation algorithm to calculates the value of conjunctive normal form. Finally,computing nodes in the reliability under different conditions, formed the probability table.,using the total probability theory to get system’s reliability approximatively.In the process of constructing the N-RGGG model, taking into account the gate logic relation. Assessment of N-RGGG, taking into account the mutual dependent components. Among them, correlation matrix describing components between two two dependent, reliability of gate logic relationship reaction in N-reliability graph with general gates.A series of ideas presented in this paper will be based on system reliability.The result showed, in the assembly between independent and existing between the components depend on circumstances,the method of the paper is more accurater.