Many mechanical systems have the characteristics of multiple failure modes and complex failure mech- anisms. On the basis of stress-strength interference （SSI） model, this paper takes the mechanical system with comm...Many mechanical systems have the characteristics of multiple failure modes and complex failure mech- anisms. On the basis of stress-strength interference （SSI） model, this paper takes the mechanical system with common cause failure （CCF） as the research object. The relationship between the stress distribution and the strength distribution is studied, and the failures of components are independent of each other under the determin- istic stress. Then, the concept of conditional reliability is introduced to build the system reliability models under the action of one-stress and multi-stress for both series and parallel systems. Finally, the corresponding properties of the DrODosed methods are discussed to show their advantages.展开更多
The lathes are basic machine tools for manufacturing cylindrical parts. In recent years, the DLseries computer numerical control(CNC) heavy-duty horizontal lathes(HDHLs) have been widely used in the transportation, en...The lathes are basic machine tools for manufacturing cylindrical parts. In recent years, the DLseries computer numerical control(CNC) heavy-duty horizontal lathes(HDHLs) have been widely used in the transportation, energy and aviation industries. High availability of the CNC heavy-duty lathes is demanded to guarantee the efficiency and benefit of these manufacturing industries. As one of the key subsystems of the HDHLs, the feeding control system is studied in this paper on reliability modeling and reliability analysis. The fault tree analysis(FTA) method is used for reliability modelling of the feeding control system. Considering the multiple common cause failure groups(CCFGs) existing in the system, a modified beta factor parametric model is introduced to model the common cause failure(CCF) in system. The reliability of feeding control system is then obtained and the effect of CCF on the reliability of the whole system is studied as well.展开更多
This paper presents reliability and availability analyses of a model representing a system having one robot and n-redundant safety units with common-cause failures. At least k safety units must function successfully f...This paper presents reliability and availability analyses of a model representing a system having one robot and n-redundant safety units with common-cause failures. At least k safety units must function successfully for the robot system success. The robot and other failure rates and the partially failed system repair rates are assumed constant and the failed robot-safety system repair time is assumed arbitrarily distributed. Markov and supplementary variable methods were used to perform mathematical analysis of this model. Generalized expressions for state probabilities, system availabilities, reliability, mean time to failure, and variance of time to failure are developed. Plots of some resulting expressions are shown.展开更多
目的:探讨失效模式与效应分析(failure mode and effect analysis,FMEA)结合根本原因分析法(root cause analysis,RCA)在多重耐药菌(multidrug-resistant organisms,MDROs)医院感染防控风险防控中的应用,为临床MDROs医院感染防控提供科...目的:探讨失效模式与效应分析(failure mode and effect analysis,FMEA)结合根本原因分析法(root cause analysis,RCA)在多重耐药菌(multidrug-resistant organisms,MDROs)医院感染防控风险防控中的应用,为临床MDROs医院感染防控提供科学有力的依据。方法:应用FMEA风险评估管理工具筛选出MDROs医院感染的高风险失效模式,联合RCA查找高风险失效模式的具体原因,制定针对性的措施规范MDROs管理的各个环节,比较风险管理前后的效果。结果:计算风险优先系数(risk priority number,RPN)值,得到5项需要采取防控措施的高风险失效模式,对高风险失效模式进行根本原因分析并实施切实有效的干预措施。干预措施实施后RPN值下降(P<0.05),MDROs医院感染率从12.48%降至7.58%,差异有统计学意义(P<0.05)。结论:FMEA结合RCA风险管理模式可以明确MDROs医院感染防控中各阶段的高风险流程,从而进行针对性的干预和标准化的管理,减少MDROs在医院的感染扩散,保障医疗安全。展开更多
Mission-critical IEC 61850 system architectures are designed to tolerate hardware failures to achieve the highest reliability performance.Hence,multi-channel systems are used in such systems within industrial faciliti...Mission-critical IEC 61850 system architectures are designed to tolerate hardware failures to achieve the highest reliability performance.Hence,multi-channel systems are used in such systems within industrial facilities to isolate machinery when there are process abnormalities.Inevitably,multi-channel systems introduce Common Cause Failure(CCF)since the subsystems can rarely be independent.This paper integrates CCF into the Markov reliability model to enhance the model flexibility to investigate synchronous generator intra-bay SCN architecture reliability performance considering the quality of repairs and CCF.The Markov process enables integration of the impact of CCF factors on system performance.The case study results indicate that CCF,coupled with imperfect repairs,significantly reduce system reliability performance.High sensitivity is observed at low levels of CCF,whereas the highest level of impact occurs when the system diagnostic coverage is 99%based on ISO 13849-1,and reduces as the diagnostic coverage level reduces.Therefore,it is concluded that the severity of CCF depends more on system diagnostic coverage level than the repair efficiency,although both factors impact the system overall performance.Hence,CCF should be con-sidered in determining the reliability performance of mission-critical communication networks in power distribution centres.展开更多
因大量采用分布式、综合化、模块化方案,复杂电子系统极易出现共因故障和故障并发等新问题,传统测试性参数确定方法难以解决。针对这一问题,提出一种基于着色广义随机Petri网(colored generalized stochastic Petri nets,CGSPN)的复杂...因大量采用分布式、综合化、模块化方案,复杂电子系统极易出现共因故障和故障并发等新问题,传统测试性参数确定方法难以解决。针对这一问题,提出一种基于着色广义随机Petri网(colored generalized stochastic Petri nets,CGSPN)的复杂电子系统测试性参数确定新方法。首先,综合需求信息、约束边界和维修保障等要求,建立电子系统两层级CGSPN模型,引入着色,实现不同模块各种状态的实时追踪和故障并发处理,通过广义随机处理共因故障的随机不确定性;然后,利用着色和可用度探索一种带有冗余设计的测试性参数处理手段,丰富测试性体系;最后,构建一种不同模块、各种状态融合的并行分析技术,统一系统层和模块层之间的状态转移关系,避免分阶段串行处理和等效替换。以通信导航识别系统为例进行实例分析,所提方法比传统方法具有更好的可用性和有效性。展开更多
目的:探讨医疗失效模式与效应分析(healthcare failure mode and effect analysis,HFMEA)结合根本原因分析(root cause analysis,RCA)在代煎中药质量管理中的应用效果。方法:组建分析团队,运用HFMEA分析代煎中药质量管理流程中的潜在失...目的:探讨医疗失效模式与效应分析(healthcare failure mode and effect analysis,HFMEA)结合根本原因分析(root cause analysis,RCA)在代煎中药质量管理中的应用效果。方法:组建分析团队,运用HFMEA分析代煎中药质量管理流程中的潜在失效模式,采用柏拉图确定关键潜在失效模式,再应用RCA法找出根本原因,拟定相应改进措施并评估干预后的效果。结果:改进措施干预后,6项关键潜在失效模式的风险优先级数(risk priority number,RPN)值均显著下降(P<0.05);各环节工作差错率由0.10%降至0.03%(χ^(2)=46.66,P<0.0001);投诉事件占比由0.07‰降至0.007‰(χ^(2)=6.711,P=0.0096);满意度评分由3.10升至4.23(P<0.01)。结论:采用HFMEA联合RCA法用于代煎中药管理可有效降低差错发生,提高患者与药师满意度,保障患者用药安全。展开更多
为提高列车自动监控系统中安全相关控制命令执行结果的可靠性和安全性,满足基于车-车通信的列车自主运行系统项目安全需求,设计一种基于中央处理单元(CPU)和图形处理单元(GPU)双链计算和显示的安全控制执行结果显示方法。操作终端的C P ...为提高列车自动监控系统中安全相关控制命令执行结果的可靠性和安全性,满足基于车-车通信的列车自主运行系统项目安全需求,设计一种基于中央处理单元(CPU)和图形处理单元(GPU)双链计算和显示的安全控制执行结果显示方法。操作终端的C P U计算的执行结果以字符串格式输出到指定位置显示,操作终端的GPU计算的执行结果以图元格式输出到标题栏位置显示。同时采用不同编码方法、相异的算法等方式,避免同一硬件设备在编码语言、算法和硬件平台的共模失效。展开更多
In view of the deficiencies in aspects such as failure rate requirements and analysis assumptions of advisory circular,this paper investigates the sources of high safety requirements,and the top-down design method for...In view of the deficiencies in aspects such as failure rate requirements and analysis assumptions of advisory circular,this paper investigates the sources of high safety requirements,and the top-down design method for the flight control system life cycle.Correspondingly,measures are proposed,including enhancing the safety target value to 10^(−10)per flight hour and implementing development assurance.In view of the shortcomings of mainstream aircraft flight control systems,such as weak backup capability and complex fault reconfiguration logic,improvements have been made to the system’s operating modes,control channel allocation,and common mode failure mitigation schemes based on the existing flight control architecture.The flight control design trends and philosophies have been analyzed.A flight control system architecture scheme is proposed,which includes three operating modes and multi-level voters/monitors,three main control channels,and a backup system independent of the main control system,which has been confirmed through functional modeling simulations.The proposed method plays an important role in the architecture design of safety-critical flight control system.展开更多
基金the National Natural Science Foundation of China(Nos.71771186 and 71471147)the 111 Project(No.B13044)the Basic Research Foundation of Northwestern Polytechnical University(No.3102014JCS05013)
文摘Many mechanical systems have the characteristics of multiple failure modes and complex failure mech- anisms. On the basis of stress-strength interference （SSI） model, this paper takes the mechanical system with common cause failure （CCF） as the research object. The relationship between the stress distribution and the strength distribution is studied, and the failures of components are independent of each other under the determin- istic stress. Then, the concept of conditional reliability is introduced to build the system reliability models under the action of one-stress and multi-stress for both series and parallel systems. Finally, the corresponding properties of the DrODosed methods are discussed to show their advantages.
基金the National Science and Technology Major Project of China(No.2014ZX04014-011)
文摘The lathes are basic machine tools for manufacturing cylindrical parts. In recent years, the DLseries computer numerical control(CNC) heavy-duty horizontal lathes(HDHLs) have been widely used in the transportation, energy and aviation industries. High availability of the CNC heavy-duty lathes is demanded to guarantee the efficiency and benefit of these manufacturing industries. As one of the key subsystems of the HDHLs, the feeding control system is studied in this paper on reliability modeling and reliability analysis. The fault tree analysis(FTA) method is used for reliability modelling of the feeding control system. Considering the multiple common cause failure groups(CCFGs) existing in the system, a modified beta factor parametric model is introduced to model the common cause failure(CCF) in system. The reliability of feeding control system is then obtained and the effect of CCF on the reliability of the whole system is studied as well.
文摘This paper presents reliability and availability analyses of a model representing a system having one robot and n-redundant safety units with common-cause failures. At least k safety units must function successfully for the robot system success. The robot and other failure rates and the partially failed system repair rates are assumed constant and the failed robot-safety system repair time is assumed arbitrarily distributed. Markov and supplementary variable methods were used to perform mathematical analysis of this model. Generalized expressions for state probabilities, system availabilities, reliability, mean time to failure, and variance of time to failure are developed. Plots of some resulting expressions are shown.
文摘目的:探讨失效模式与效应分析(failure mode and effect analysis,FMEA)结合根本原因分析法(root cause analysis,RCA)在多重耐药菌(multidrug-resistant organisms,MDROs)医院感染防控风险防控中的应用,为临床MDROs医院感染防控提供科学有力的依据。方法:应用FMEA风险评估管理工具筛选出MDROs医院感染的高风险失效模式,联合RCA查找高风险失效模式的具体原因,制定针对性的措施规范MDROs管理的各个环节,比较风险管理前后的效果。结果:计算风险优先系数(risk priority number,RPN)值,得到5项需要采取防控措施的高风险失效模式,对高风险失效模式进行根本原因分析并实施切实有效的干预措施。干预措施实施后RPN值下降(P<0.05),MDROs医院感染率从12.48%降至7.58%,差异有统计学意义(P<0.05)。结论:FMEA结合RCA风险管理模式可以明确MDROs医院感染防控中各阶段的高风险流程,从而进行针对性的干预和标准化的管理,减少MDROs在医院的感染扩散,保障医疗安全。
文摘Mission-critical IEC 61850 system architectures are designed to tolerate hardware failures to achieve the highest reliability performance.Hence,multi-channel systems are used in such systems within industrial facilities to isolate machinery when there are process abnormalities.Inevitably,multi-channel systems introduce Common Cause Failure(CCF)since the subsystems can rarely be independent.This paper integrates CCF into the Markov reliability model to enhance the model flexibility to investigate synchronous generator intra-bay SCN architecture reliability performance considering the quality of repairs and CCF.The Markov process enables integration of the impact of CCF factors on system performance.The case study results indicate that CCF,coupled with imperfect repairs,significantly reduce system reliability performance.High sensitivity is observed at low levels of CCF,whereas the highest level of impact occurs when the system diagnostic coverage is 99%based on ISO 13849-1,and reduces as the diagnostic coverage level reduces.Therefore,it is concluded that the severity of CCF depends more on system diagnostic coverage level than the repair efficiency,although both factors impact the system overall performance.Hence,CCF should be con-sidered in determining the reliability performance of mission-critical communication networks in power distribution centres.
文摘因大量采用分布式、综合化、模块化方案,复杂电子系统极易出现共因故障和故障并发等新问题,传统测试性参数确定方法难以解决。针对这一问题,提出一种基于着色广义随机Petri网(colored generalized stochastic Petri nets,CGSPN)的复杂电子系统测试性参数确定新方法。首先,综合需求信息、约束边界和维修保障等要求,建立电子系统两层级CGSPN模型,引入着色,实现不同模块各种状态的实时追踪和故障并发处理,通过广义随机处理共因故障的随机不确定性;然后,利用着色和可用度探索一种带有冗余设计的测试性参数处理手段,丰富测试性体系;最后,构建一种不同模块、各种状态融合的并行分析技术,统一系统层和模块层之间的状态转移关系,避免分阶段串行处理和等效替换。以通信导航识别系统为例进行实例分析,所提方法比传统方法具有更好的可用性和有效性。
文摘目的:探讨医疗失效模式与效应分析(healthcare failure mode and effect analysis,HFMEA)结合根本原因分析(root cause analysis,RCA)在代煎中药质量管理中的应用效果。方法:组建分析团队,运用HFMEA分析代煎中药质量管理流程中的潜在失效模式,采用柏拉图确定关键潜在失效模式,再应用RCA法找出根本原因,拟定相应改进措施并评估干预后的效果。结果:改进措施干预后,6项关键潜在失效模式的风险优先级数(risk priority number,RPN)值均显著下降(P<0.05);各环节工作差错率由0.10%降至0.03%(χ^(2)=46.66,P<0.0001);投诉事件占比由0.07‰降至0.007‰(χ^(2)=6.711,P=0.0096);满意度评分由3.10升至4.23(P<0.01)。结论:采用HFMEA联合RCA法用于代煎中药管理可有效降低差错发生,提高患者与药师满意度,保障患者用药安全。
文摘为提高列车自动监控系统中安全相关控制命令执行结果的可靠性和安全性,满足基于车-车通信的列车自主运行系统项目安全需求,设计一种基于中央处理单元(CPU)和图形处理单元(GPU)双链计算和显示的安全控制执行结果显示方法。操作终端的C P U计算的执行结果以字符串格式输出到指定位置显示,操作终端的GPU计算的执行结果以图元格式输出到标题栏位置显示。同时采用不同编码方法、相异的算法等方式,避免同一硬件设备在编码语言、算法和硬件平台的共模失效。
文摘In view of the deficiencies in aspects such as failure rate requirements and analysis assumptions of advisory circular,this paper investigates the sources of high safety requirements,and the top-down design method for the flight control system life cycle.Correspondingly,measures are proposed,including enhancing the safety target value to 10^(−10)per flight hour and implementing development assurance.In view of the shortcomings of mainstream aircraft flight control systems,such as weak backup capability and complex fault reconfiguration logic,improvements have been made to the system’s operating modes,control channel allocation,and common mode failure mitigation schemes based on the existing flight control architecture.The flight control design trends and philosophies have been analyzed.A flight control system architecture scheme is proposed,which includes three operating modes and multi-level voters/monitors,three main control channels,and a backup system independent of the main control system,which has been confirmed through functional modeling simulations.The proposed method plays an important role in the architecture design of safety-critical flight control system.
