The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with ...The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing.展开更多
飞行控制系统作为电动垂直起降(electric vertical take-off and landing,eVTOL)飞行器的关键机载系统,需要具备和民机同样的安全性。为了设计满足eVTOL飞行器需求的飞控系统架构,根据适航规章梳理了安全性要求,并基于安全性要求介绍了e...飞行控制系统作为电动垂直起降(electric vertical take-off and landing,eVTOL)飞行器的关键机载系统,需要具备和民机同样的安全性。为了设计满足eVTOL飞行器需求的飞控系统架构,根据适航规章梳理了安全性要求,并基于安全性要求介绍了eVTOL飞行器飞控系统飞控计算机、传感器和作动器余度设计技术,设计了一种基于安全性考虑的eVTOL飞行器飞控系统架构;分析了eVTOL飞行器旋翼构型下的典型功能危险,并采用故障树进行了安全性分析。结果表明,设计的飞控系统架构的典型功能危险能够满足失效概率的要求。展开更多
目的:运用网状Meta分析不同中药注射液治疗糖尿病周围神经病变(DPN)的疗效和安全性。方法:基于PubMed、Cochrane Library、EMbase、Web of Science、国家知识基础设施数据库(CNKI)、中文科技期刊数据库(CCD)、中国学术期刊数据库(CSPD)...目的:运用网状Meta分析不同中药注射液治疗糖尿病周围神经病变(DPN)的疗效和安全性。方法:基于PubMed、Cochrane Library、EMbase、Web of Science、国家知识基础设施数据库(CNKI)、中文科技期刊数据库(CCD)、中国学术期刊数据库(CSPD)、中国生物医学文献数据库(CBM),检索中药注射液治疗DPN的随机对照试验(RCTs),将临床总有效率作为主要结局指标,正中和腓总的感觉神经传导速度(SCV)及运动神经传导速度(MCV)、空腹血糖(FBG)及不良反应作为次要结局指标。采用Cochrane评价手册5.3风险偏倚评估工具进行质量评价及RevMan 5.4.1及Stata 17软件进行数据分析。结果:共纳入76项RCTs,包括6 108例患者,11种中药注射液。网状Meta分析结果显示,丹参多酚酸盐注射液联合西药在提高临床总有效率和改善FBG水平方面疗效最佳;苦碟子注射液联合西药在改善正中神经及腓总神经的SCV、正中神经MCV方面疗效最佳;血塞通注射液联合西药在改善腓总神经MCV方面疗效最佳;在安全性方面,中药注射液联合西药与单纯西药治疗比较差异无统计学意义。结论:中药注射液联合西药与单纯西药治疗比较可提高DPN临床疗效,且未增加不良反应的发生。展开更多
为了研究管制员飞行冲突调配的人因差错问题,进而有效评估管制员解决飞行冲突的可靠性,以保障空中交通的安全运行,提出系统理论过程分析(System Theoretic Process Analysis, STPA)与认知可靠性与失误分析方法(Cognitive Reliability an...为了研究管制员飞行冲突调配的人因差错问题,进而有效评估管制员解决飞行冲突的可靠性,以保障空中交通的安全运行,提出系统理论过程分析(System Theoretic Process Analysis, STPA)与认知可靠性与失误分析方法(Cognitive Reliability and Error Analysis Method, CREAM)相结合的人因可靠性分析方法。首先,通过STPA方法构建系统控制模型,识别不安全控制行为(Unsafe Control Action, UCA)以及致因因素,找到管制员在调配飞行冲突过程中可能存在的差错行为;其次,基于CREAM扩展法对管制员的差错行为进行定量分析,得到管制员调配飞行冲突的人因失误概率。研究显示:使用该方法能够系统、全面地识别出管制员在调配飞行冲突过程中出现的差错行为,进而计算管制员飞行冲突调配的人因失误概率。实例分析表明该方法可以预测管制员在飞行冲突调配过程中的人因失误概率及可靠性,为管制员人因可靠性分析提供了新思路。展开更多
文摘The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing.
文摘光束线站真空安全联锁是保障同步辐射光源储存环的运行安全与线站关键设备安全的重要系统。文章阐述了合肥光源新建成的金华光束线站真空安全联锁系统的最新设计方法。基于新型的高性能可编程控制器PLC(Programmable Logic Controller)和开放的软件平台EPICS 7(Experimental Physics and Industrial Control System)分布式控制系统架构,同时采用虚拟化技术,开发了全新的光束线站真空安全联锁系统。在系统远控的OPI界面开发上,采用Python脚本一键自动生成,提高了系统开发效率。此次设计在确保系统安全性和可靠性的同时,系统的性能以及用户人机交互的体验都得以提升。这些设计方法为正在建设的合肥先进光源的光束线站控制提供了技术储备和实践经验。
基金supported by the National Nature Science Foundation of China(61304223)the Aeronautical Science Foundation of China(2016ZA52009)the Research Fund for the Doctoral Program of Higher Education of China(20123218120015)
文摘飞行控制系统作为电动垂直起降(electric vertical take-off and landing,eVTOL)飞行器的关键机载系统,需要具备和民机同样的安全性。为了设计满足eVTOL飞行器需求的飞控系统架构,根据适航规章梳理了安全性要求,并基于安全性要求介绍了eVTOL飞行器飞控系统飞控计算机、传感器和作动器余度设计技术,设计了一种基于安全性考虑的eVTOL飞行器飞控系统架构;分析了eVTOL飞行器旋翼构型下的典型功能危险,并采用故障树进行了安全性分析。结果表明,设计的飞控系统架构的典型功能危险能够满足失效概率的要求。
文摘为了研究管制员飞行冲突调配的人因差错问题,进而有效评估管制员解决飞行冲突的可靠性,以保障空中交通的安全运行,提出系统理论过程分析(System Theoretic Process Analysis, STPA)与认知可靠性与失误分析方法(Cognitive Reliability and Error Analysis Method, CREAM)相结合的人因可靠性分析方法。首先,通过STPA方法构建系统控制模型,识别不安全控制行为(Unsafe Control Action, UCA)以及致因因素,找到管制员在调配飞行冲突过程中可能存在的差错行为;其次,基于CREAM扩展法对管制员的差错行为进行定量分析,得到管制员调配飞行冲突的人因失误概率。研究显示:使用该方法能够系统、全面地识别出管制员在调配飞行冲突过程中出现的差错行为,进而计算管制员飞行冲突调配的人因失误概率。实例分析表明该方法可以预测管制员在飞行冲突调配过程中的人因失误概率及可靠性,为管制员人因可靠性分析提供了新思路。
