Safety Critical Systems (SCS) are those systems that may cause harm to the user(s) and/or the environment if operating outside of their prescribed specifications. Such systems are used in a wide variety of domains, su...Safety Critical Systems (SCS) are those systems that may cause harm to the user(s) and/or the environment if operating outside of their prescribed specifications. Such systems are used in a wide variety of domains, such as aerospace, automotive, railway transportation and healthcare. In this paper, we propose an approach to integrate safety analysis of SCSs within the Model Driven Engineering (MDE) system development process. The approach is based on model transformation and uses standard well-known techniques and open source tools for the modeling and analysis of SCSs. More specifically, the system modeled with the OMG’s standard systems modeling language, SysML, is automatically transformed in Fault Tree (FT) models, that can be analyzed with existing FT tools. The proposed model transformation takes place in two steps: a) generate FTs at the component level, in order to tackle complexity and enable reuse;and b) generate system level FTs by composing the components and their FTs. The approach is illustrated by applying it to a simplified industry-inspired case study.展开更多
A state/event fault tree(SEFT)is a modeling technique for describing the causal chains of events leading to failure in software-controlled complex systems.Such systems are ubiquitous in all areas of everyday life,and ...A state/event fault tree(SEFT)is a modeling technique for describing the causal chains of events leading to failure in software-controlled complex systems.Such systems are ubiquitous in all areas of everyday life,and safety and reliability analyses are increasingly required for these systems.SEFTs combine elements from the traditional fault tree with elements from state-based techniques.In the context of the real-time safety-critical systems,SEFTs do not describe the time properties and important timedependent system behaviors that can lead to system failures.Further,SEFTs lack the precise semantics required for formally modeling time behaviors.In this paper,we present a qualitative analysis method for SEFTs based on transformation from SEFT to timed automata(TA),and use the model checker UPPAAL to verify system requirements’properties.The combination of SEFT and TA is an important step towards an integrated design and verification process for real-time safety-critical systems.Finally,we present a case study of a powerboat autopilot system to confirm our method is viable and valid after achieving the verification goal step by step.展开更多
A combined logic- and model-based approach to fault detection and identification （FDI） in a suction foot control system of a wall-climbing robot is presented in this paper. For the control system, some fault models ...A combined logic- and model-based approach to fault detection and identification （FDI） in a suction foot control system of a wall-climbing robot is presented in this paper. For the control system, some fault models are derived by kinematics analysis. Moreover, the logic relations of the system states are known in advance. First, a fault tree is used to analyze the system by evaluating the basic events （elementary causes）, which can lead to a root event （a particular fault）. Then, a multiple-model adaptive estimation algorithm is used to detect and identify the model-known faults. Finally, based on the system states of the robot and the results of the estimation, the model-unknown faults are also identified using logical reasoning. Experiments show that the proposed approach based on the combination of logical reasoning and model estimating is efficient in the FDI of the robot.展开更多
针对复杂系统设计过程缺乏早期可靠性评估的问题,提出一种基于模型的系统工程方法支持复杂系统的设计及可靠性评估。结合复杂系统的研发特点,提出一种基于“使命、运行、功能、逻辑、物理、可靠性”的基于模型的系统工程(model-based sy...针对复杂系统设计过程缺乏早期可靠性评估的问题,提出一种基于模型的系统工程方法支持复杂系统的设计及可靠性评估。结合复杂系统的研发特点,提出一种基于“使命、运行、功能、逻辑、物理、可靠性”的基于模型的系统工程(model-based systems engineering, MBSE)建模方法,支持复杂系统设计和可靠性评估;利用基于“图、对象、属性、点、关系、角色”的系统建模语言KARMA对上述过程进行统一表达;通过KARMA的代码生成功能实现图模型到计算模型的映射,完成复杂系统可靠性的评估;将方法应用于液压系统案例,结果表明所提方法对于复杂系统设计和评估具备有效性。展开更多
目的探讨故障树分析(Fault Tree Analysis,FTA)对硬镜故障分析应用的效果。方法回顾分析本院2个阶段(2019—2021年和2022—2023年)硬镜故障维修单,第一阶段经统计汇总47例,第二阶段经统计汇总10例,第一阶段运用FTA建立硬镜故障树模型,...目的探讨故障树分析(Fault Tree Analysis,FTA)对硬镜故障分析应用的效果。方法回顾分析本院2个阶段(2019—2021年和2022—2023年)硬镜故障维修单,第一阶段经统计汇总47例,第二阶段经统计汇总10例,第一阶段运用FTA建立硬镜故障树模型,进行定性和定量分析,计算顶事件发生概率,以相同方法计算出第二阶段顶事件发生概率。结果通过硬镜故障树模型确定其函数T,通过定性分析获得28个最小割集,通过定量分析计算出顶事件发生的概率P(T)=0.22568116,计算出各个基本事件的重要度系数,分析找到对顶事件影响最大的十个基本事件,制定医疗器械质量管理方案,使原先22.57%的故障率降低至5.87%。结论FTA可有效应用于硬镜故障诊断,针对基本事件进行改进,从而降低器械故障率,减少维修成本,并显著延长硬镜使用寿命。展开更多
There were various conventional modeling techniques with varied semantics for system reliability assessment, such as fault trees(FT), Markov process(MP), and Petri nets. However, it is strenuous to construct and to ma...There were various conventional modeling techniques with varied semantics for system reliability assessment, such as fault trees(FT), Markov process(MP), and Petri nets. However, it is strenuous to construct and to maintain models utilizing these formalisms throughout the life cycle of system under development. This paper proposes a unified formal modeling language to build a general reliability model. The method eliminates the gap between the actual system and reliability model and shows details of the system clearly. Furthermore,the model could be transformed into FT and MP through specific rules defined by a formal language to assess system-level reliability.展开更多
Fault tree analysis is an effective method for predicting the reliability of a system. It gives a pictorial representation and logical framework for analyzing the reliability. Also, it has been used for a long time as...Fault tree analysis is an effective method for predicting the reliability of a system. It gives a pictorial representation and logical framework for analyzing the reliability. Also, it has been used for a long time as an effective method for the quantitative and qualitative analysis of the failure modes of critical systems. In this paper, we propose a new general coverage model （GCM） based on hardware independent faults. Using this model, an effective software tool can be constructed to detect, locate and recover fault from the faulty system. This model can be applied to identify the key component that can cause the failure of the system using failure mode effect analysis （FMEA）.展开更多
文摘Safety Critical Systems (SCS) are those systems that may cause harm to the user(s) and/or the environment if operating outside of their prescribed specifications. Such systems are used in a wide variety of domains, such as aerospace, automotive, railway transportation and healthcare. In this paper, we propose an approach to integrate safety analysis of SCSs within the Model Driven Engineering (MDE) system development process. The approach is based on model transformation and uses standard well-known techniques and open source tools for the modeling and analysis of SCSs. More specifically, the system modeled with the OMG’s standard systems modeling language, SysML, is automatically transformed in Fault Tree (FT) models, that can be analyzed with existing FT tools. The proposed model transformation takes place in two steps: a) generate FTs at the component level, in order to tackle complexity and enable reuse;and b) generate system level FTs by composing the components and their FTs. The approach is illustrated by applying it to a simplified industry-inspired case study.
基金supported by the National Natural Science Foundation of China(11832012)
文摘A state/event fault tree(SEFT)is a modeling technique for describing the causal chains of events leading to failure in software-controlled complex systems.Such systems are ubiquitous in all areas of everyday life,and safety and reliability analyses are increasingly required for these systems.SEFTs combine elements from the traditional fault tree with elements from state-based techniques.In the context of the real-time safety-critical systems,SEFTs do not describe the time properties and important timedependent system behaviors that can lead to system failures.Further,SEFTs lack the precise semantics required for formally modeling time behaviors.In this paper,we present a qualitative analysis method for SEFTs based on transformation from SEFT to timed automata(TA),and use the model checker UPPAAL to verify system requirements’properties.The combination of SEFT and TA is an important step towards an integrated design and verification process for real-time safety-critical systems.Finally,we present a case study of a powerboat autopilot system to confirm our method is viable and valid after achieving the verification goal step by step.
基金supported by the Hi-tech Research and Development Program of China (No.2006AA420203)
文摘A combined logic- and model-based approach to fault detection and identification （FDI） in a suction foot control system of a wall-climbing robot is presented in this paper. For the control system, some fault models are derived by kinematics analysis. Moreover, the logic relations of the system states are known in advance. First, a fault tree is used to analyze the system by evaluating the basic events （elementary causes）, which can lead to a root event （a particular fault）. Then, a multiple-model adaptive estimation algorithm is used to detect and identify the model-known faults. Finally, based on the system states of the robot and the results of the estimation, the model-unknown faults are also identified using logical reasoning. Experiments show that the proposed approach based on the combination of logical reasoning and model estimating is efficient in the FDI of the robot.
文摘目的洪水是影响尾矿库安全的重要因素,明晰洪水对尾矿库的风险传导路径有利于帮助识别关键风险因素,优化防控措施。方法结合文献计量法和专家决策筛选出尾矿库洪水风险的重要影响指标,利用解释结构模型(interpretative structural modeling,ISM)对指标层次进行划分,最后基于事故树分析(fault tree analysis,FTA)解析灾害的演化路径,并提出相应预防措施。结果结果表明:(1)基于文献计量法总共筛选出24个尾矿库洪水风险影响因素,结合平均权重值与专家经验确定10个相对重要的尾矿库洪水风险影响因素;(2)基于ISM计算得出10个影响因素和洪水风险间的相互影响关系,确定尾矿库洪水灾害的直接、间接和最根本影响因素;(3)结合ISM和事故案例,建立尾矿库洪水灾害事故树,通过布尔代数运算得出18种致灾路径和9种预防事故的路径;(4)分析事故树的结构重要度后发现对尾矿库洪水风险影响最大的事件是排洪能力不足、洪峰流量大和初始浸润线埋深浅。结论提出的文献计量法、ISM与FTA相结合的方法不仅实现了客观指标筛选与系统建模的融合,而且为尾矿库防洪实现从“被动应对”向“主动阻断”的转变提供了理论支撑。
文摘针对复杂系统设计过程缺乏早期可靠性评估的问题,提出一种基于模型的系统工程方法支持复杂系统的设计及可靠性评估。结合复杂系统的研发特点,提出一种基于“使命、运行、功能、逻辑、物理、可靠性”的基于模型的系统工程(model-based systems engineering, MBSE)建模方法,支持复杂系统设计和可靠性评估;利用基于“图、对象、属性、点、关系、角色”的系统建模语言KARMA对上述过程进行统一表达;通过KARMA的代码生成功能实现图模型到计算模型的映射,完成复杂系统可靠性的评估;将方法应用于液压系统案例,结果表明所提方法对于复杂系统设计和评估具备有效性。
文摘目的探讨故障树分析(Fault Tree Analysis,FTA)对硬镜故障分析应用的效果。方法回顾分析本院2个阶段(2019—2021年和2022—2023年)硬镜故障维修单,第一阶段经统计汇总47例,第二阶段经统计汇总10例,第一阶段运用FTA建立硬镜故障树模型,进行定性和定量分析,计算顶事件发生概率,以相同方法计算出第二阶段顶事件发生概率。结果通过硬镜故障树模型确定其函数T,通过定性分析获得28个最小割集,通过定量分析计算出顶事件发生的概率P(T)=0.22568116,计算出各个基本事件的重要度系数,分析找到对顶事件影响最大的十个基本事件,制定医疗器械质量管理方案,使原先22.57%的故障率降低至5.87%。结论FTA可有效应用于硬镜故障诊断,针对基本事件进行改进,从而降低器械故障率,减少维修成本,并显著延长硬镜使用寿命。
文摘安全隐患、未遂事故等异常事件是小事故升级为重大事故的早期预警,可用来建立事故模型识别源头事件及纠正保护系统中的不安全因素。结合液化天然气(LNG)库区的工艺特点和事故特征,对系统危害辨识、预测及预防(system hazard identification,prediction and prevention,SHIPP)模型改进,提出一种将故障树、贝叶斯网络与A-star算法融合的风险评估建模方法。首先依托专家经验,结合事故报警数据库中的异常事件建立安全屏障模型和故障树;然后遵循链式法则将故障树映射为贝叶斯网络;最后与改进的A-star算法融合确定事故发生途径。基于LNG事故报警数据库的研究表明,该方法相较于传统的SHIPP模型,可以实现动态前向风险评估并量化事故之间的条件概率,反向模拟安全屏障失效时的事故发生过程。研究成果可为LNG库区的系统安全、风险规避提供合理设计及决策。
文摘There were various conventional modeling techniques with varied semantics for system reliability assessment, such as fault trees(FT), Markov process(MP), and Petri nets. However, it is strenuous to construct and to maintain models utilizing these formalisms throughout the life cycle of system under development. This paper proposes a unified formal modeling language to build a general reliability model. The method eliminates the gap between the actual system and reliability model and shows details of the system clearly. Furthermore,the model could be transformed into FT and MP through specific rules defined by a formal language to assess system-level reliability.
文摘Fault tree analysis is an effective method for predicting the reliability of a system. It gives a pictorial representation and logical framework for analyzing the reliability. Also, it has been used for a long time as an effective method for the quantitative and qualitative analysis of the failure modes of critical systems. In this paper, we propose a new general coverage model （GCM） based on hardware independent faults. Using this model, an effective software tool can be constructed to detect, locate and recover fault from the faulty system. This model can be applied to identify the key component that can cause the failure of the system using failure mode effect analysis （FMEA）.
