Testability design is an effective way to realize the fault detection and isolation.Its important step is to determine testability figures of merits(TFOM).Firstly,some influence factors for TFOMs are analyzed,such as ...Testability design is an effective way to realize the fault detection and isolation.Its important step is to determine testability figures of merits(TFOM).Firstly,some influence factors for TFOMs are analyzed,such as the processes of system operation,maintenance and support,fault detection and isolation and so on.Secondly,a testability requirement analysis model is built based on generalized stochastic Petri net(GSPN).Then,the system's reachable states are analyzed based on the model,a Markov chain isomorphic with Petri net is constructed,a state transition matrix is created and the system's steady state probability is obtained.The relationship between the steady state availability and testability parameters can be revealed and reasoned.Finally,an example shows that the proposed method can determine TFOM,such as fault detection rate and fault isolation rate,effectively and reasonably.展开更多
In this paper, data streams are classified into four types conforming to a standardized infrastructure of communication networks for a substation automation system (SAS) based on IEC61850 system. The data exchanged on...In this paper, data streams are classified into four types conforming to a standardized infrastructure of communication networks for a substation automation system (SAS) based on IEC61850 system. The data exchanged on the net are demonstrated to be stochastic according to investigation on the Ethernet communication principles. Four generalized stochastic Petri nets (GSPN) based models for performance analysis of communication networks of IEC61850 system are developed based on the three-level structure of SAS, different time requirements of the four data streams and different networks topology for different voltage level. The GSPN-based model associated with immediate and exponential transitions is proven to be theoretically isomorphic with Markov chain; hence we apply the mathematic methods of performance evaluation contained in Markov chain to the GSPN models proposed. The computer simulation of the model including only sample value data streams shows that it can meet performance evaluation needs of communication networks of IEC61850 system. Further researches should be focused on the performance of the other three models to explain clear how those different data streams are interrelated to and interact on each other.展开更多
针对传统可靠性建模方法难以描述和评价网络系统动态可靠性这一难题,提出一种基于广义随机Petri网(generalized sto-chastic petri net,GSPN)的网络系统动态可靠性建模方法,在讨论GSPN的形式化定义和建立GSPN建模要素与可靠性模型参数...针对传统可靠性建模方法难以描述和评价网络系统动态可靠性这一难题,提出一种基于广义随机Petri网(generalized sto-chastic petri net,GSPN)的网络系统动态可靠性建模方法,在讨论GSPN的形式化定义和建立GSPN建模要素与可靠性模型参数之间对应关系的基础上,详细描述了网络系统动态可靠性建模的过程;最后以某型车电系统为例,通过仿真实验得到了系统可用度指标的动态变化曲线,验证了所提方法的有效性。展开更多
应用混合Petri网建立故障诊断模型,应用广义随机Petri网建立Boe ing 777非相似余度飞控计算机故障行为模型.描述了非相似余度系统的结构以及故障的产生和传播的动态过程,分析了该系统的可靠度和容错度,并有效地消除了瞬态故障对分析系...应用混合Petri网建立故障诊断模型,应用广义随机Petri网建立Boe ing 777非相似余度飞控计算机故障行为模型.描述了非相似余度系统的结构以及故障的产生和传播的动态过程,分析了该系统的可靠度和容错度,并有效地消除了瞬态故障对分析系统可靠性的影响.展开更多
应用广义随机Petri网方法,对柔性制造系统进行建模和分析,提出了控制策略和优化方法。针对柔性制造系统的离散性,对整个系统的过程模型进行分析。利用广义随机 Petri 网结合马尔可夫链的方法,确立了系统的配置参数,得出了系统的平均运...应用广义随机Petri网方法,对柔性制造系统进行建模和分析,提出了控制策略和优化方法。针对柔性制造系统的离散性,对整个系统的过程模型进行分析。利用广义随机 Petri 网结合马尔可夫链的方法,确立了系统的配置参数,得出了系统的平均运行时间,机床的平均使用率,系统的生产率,故障概率,对系统的优化和生产效率的提高以及柔性的提高提供了理论支持。最后,通过柔性制造系统实例,对该方法进行了检验。展开更多
文摘Testability design is an effective way to realize the fault detection and isolation.Its important step is to determine testability figures of merits(TFOM).Firstly,some influence factors for TFOMs are analyzed,such as the processes of system operation,maintenance and support,fault detection and isolation and so on.Secondly,a testability requirement analysis model is built based on generalized stochastic Petri net(GSPN).Then,the system's reachable states are analyzed based on the model,a Markov chain isomorphic with Petri net is constructed,a state transition matrix is created and the system's steady state probability is obtained.The relationship between the steady state availability and testability parameters can be revealed and reasoned.Finally,an example shows that the proposed method can determine TFOM,such as fault detection rate and fault isolation rate,effectively and reasonably.
文摘In this paper, data streams are classified into four types conforming to a standardized infrastructure of communication networks for a substation automation system (SAS) based on IEC61850 system. The data exchanged on the net are demonstrated to be stochastic according to investigation on the Ethernet communication principles. Four generalized stochastic Petri nets (GSPN) based models for performance analysis of communication networks of IEC61850 system are developed based on the three-level structure of SAS, different time requirements of the four data streams and different networks topology for different voltage level. The GSPN-based model associated with immediate and exponential transitions is proven to be theoretically isomorphic with Markov chain; hence we apply the mathematic methods of performance evaluation contained in Markov chain to the GSPN models proposed. The computer simulation of the model including only sample value data streams shows that it can meet performance evaluation needs of communication networks of IEC61850 system. Further researches should be focused on the performance of the other three models to explain clear how those different data streams are interrelated to and interact on each other.
文摘针对传统可靠性建模方法难以描述和评价网络系统动态可靠性这一难题,提出一种基于广义随机Petri网(generalized sto-chastic petri net,GSPN)的网络系统动态可靠性建模方法,在讨论GSPN的形式化定义和建立GSPN建模要素与可靠性模型参数之间对应关系的基础上,详细描述了网络系统动态可靠性建模的过程;最后以某型车电系统为例,通过仿真实验得到了系统可用度指标的动态变化曲线,验证了所提方法的有效性。
文摘应用广义随机Petri网方法,对柔性制造系统进行建模和分析,提出了控制策略和优化方法。针对柔性制造系统的离散性,对整个系统的过程模型进行分析。利用广义随机 Petri 网结合马尔可夫链的方法,确立了系统的配置参数,得出了系统的平均运行时间,机床的平均使用率,系统的生产率,故障概率,对系统的优化和生产效率的提高以及柔性的提高提供了理论支持。最后,通过柔性制造系统实例,对该方法进行了检验。
