Research On Reliability Modeling And Evaluation Of Complex Multi-state System Based On Universal Generating Function

With the rapid development of modern society and economy,people have put forward higher and higher requirements for product reliability.With the increase in production requirements and functions,multi-state systems are becoming more and more complex.The complexity is mainly reflected in three aspects.Firstly,the complexity of the system structure causes the complex system.Secondly,the internal and external factors that affect the state of the system are diverse and complex;Thirdly,the complication caused by the relevance and dynamics of the system components and the working environment.Therefore,when evaluating the reliability of complex multi-state systems and conducting optimization research,how to quantitatively describe the complexity and related behaviors that the system faces during operation has become a hot and difficult point in current.Based on the actual system,this paper studies three main factors that lead to system complexity,namely performance sharing mechanism,phased mission systems and system structure complexity.The random process theory is used to construct reliability models of complex multi-state systems in different situations.The main research content of the paper includes the following aspects.Firstly,model and optimize the reliability of distributed computing systems with performance sharing mechanisms.This paper proposes the definition of the reliability of a distributed computing system with performance sharing mechanism.Construct the optimization model of the allocation strategy of each computer's computing power.Secondly,model and optimize the reliability of multi-state systems considering common bus with performance loss.Inspired by the power systems and communication systems,the performance transmission loss is considered for the multi-state system with performance sharing mechanism.Combined with the reality,the reliability of the multi-state system under three different performance transmission loss modes is proposed.To further improve the system reliability,a joint optimization model of component protection strategy and maintenance management was constructed.Thirdly,model and optimize the reliability of a linear sliding window system with phased missions.Inspired by an industrial heating system,a linear sliding window system is expanded from a single-phase mission to a phased mission system,where the performance degradation of the multi-state components is considered.Propose the system reliability model and derive the evaluation algorithm.In order to increase the practicability of the research results,the component allocation strategy is optimized to maximize the system reliability.Fourthly,model and optimize the reliability of distributed data storage systems with phased missions.Taking into account the fact that people have different requirements for the use of data stored in the distributed data storage system in different phases,the distributed data storage system is extended to a phased mission system.The complex situation that the system faces hacker attacks and internal computer degradation is considered.In addition,the system reliability models and corresponding evaluation algorithms are derived for two attack modes of hackers,i.e.,data destruction and data theft.Moreover,the data copy and allocation strategy are studied.Finally,model and optimize the reliability of two-dimensional complex systems.Inspired by the matrix industrial system,the definition of the reliability of a two-dimensional demand-based networked system with multi-state components and a two-dimensional sliding window system is proposed for the first time.The reliability models of two types of systems are constructed respectively and the corresponding calculation formulas of reliability evaluation algorithms are derived.Besides,the two-dimensional demand-based networked system is expanded from a single-phase mission to a phased mission system,which each component performance degradation process is described by continuous-time Markov chain.In addition,two types of system component allocation strategies are optimized and modeled.The two-dimensional sliding window system also considers the joint optimization problem of component allocation and maintenance management.