Deep learning of system reliability under multi-factor influence based on space fault tree

Neural Computing and Applications - For the fault tree analysis, a basic event probability is often complicated. The probability is not constant and even can be represented by function. In order to...     

软件可靠度的模糊故障树评定方法

软件可靠性的定量评价是软件可靠性工程的关键问题之一,采用故障树方法对软件进行定性和定量分析,提出了两类情况下对影响软件可靠性的主次因素划分及其模糊权重的计算方法。在此基础上,建立多级模糊评价模型,提出了增广和聚合算法,并给出了软件可靠度算式。选择某型航空装备软件进行了测试实例分析,实验结果表明了该方法评价结构的合理性与评价算法的有效性,适用于软件质量及开发过程控制的工程实践。     

空间故障树与因素空间融合的智能可靠性分析方法

现有系统可靠性分析方法一般具有针对性,缺乏广泛的适应性和扩展性。由于智能科学、信息科学和大数据技术的涌现和发展,使得传统可靠性分析技术难以适应新的需要。因此作者提出了空间故障树理论,目的是分析多因素影响下的系统可靠性变化特征。将空间故障树理论与因素空间理论、云模型、模糊数学及系统稳定性等相结合,使其具有智能分析和故障大数据处理能力,以满足未来技术环境下的分析要求。本文论述了空间故障树和因素空间的发展史及主要理论与功能;以及两种理论结合,描述和分析系统演化过程的可行性。研究表明,空间故障树理论具有良好的扩展性和适应性,可适应未来技术环境,也可作为系统演化过程分析的普适框架。     

基于故障树的等级测评专家系统模型研究*

结合等级测评、风险评估和专家系统的相关技术,提出了一种将故障树和专家系统技术用于等级测评结果的综合分析模型。该模型通过将评价标准转换成规则固化在知识库中,利用故障树对知识进行展示和分析,并利用不确定推理方法对评估事实进行推理,得到该信息系统存在的安全问题可能会发生什么安全事件,从而紧密地将等级保护要求和用户安全需求联系在一起,极大地提高了用户实践等级保护的积极性,并为等级测评与风险评估有机结合提供了一种新的思路。另外,本系统还利用粗糙集理论从信息安全事件中自动获取推理规则,使得推理规则能随着安全状态的变化     

基于故障树的无线传感器网络可靠度符号计算

以无线传感器网络（WSN ）中应用通信可靠性（ACR）为背景,利用故障树模型中的事件元素与逻辑门元素,建立基于故障树的WSN可靠性结构。为降低WSN可靠度计算的复杂性,给出从WSN可靠性结构转换到二元决策图BDD结构的算法,利用BDD算法优化计算过程。以分层簇型网络中可用路径以及节点冗余下的应用通信可靠性问题为例,给出其可靠性结构,利用CUDD软件包给出用递归方法实现构建基于故障树的WSN可靠性结构的BDD算法,计算以上两种情况下的WSN可靠度。实验结果表明,该方法具有可行性。     

化工原理实验数据处理软件的开发

本软件旨在解决通常的化工原理实验数据处理过程中或因计算复杂,或因作图时不可避免的出错而影响实验结果的问题.它以Visual Basic 6.0为开发工具,采用最小二乘法直线拟合、非线性拟合、数值积分等方法处理实验数据,可完全消除学生作图出错,使实验结果更正确、更科学.本软件为处理化工原理实验数据提供方便、快捷的方法,也为教师批改实验报告提供可靠的依据.该软件在中文Windows环境中运行,界面美观、操作方便.     

MatCarloRe: An integrated FT and Monte Carlo Simulink tool for the reliability assessment of dynamic fault tree

With the aim of a more effective representation of reliability assessment for real industry, in the last years concepts like dynamic fault trees (DFT) have gained the interest of many researchers and engineers (dealing with problems concerning safety management, design and development of new products, decision analysis and project management, maintenance of industrial plant, etc.). With the increased computational power of modern calculators is possible to achieve results with low modeling efforts and calculating time. Supported by the strong mathematical basis of state space models, the DFT technique has increased its popularity. Nevertheless, DFT analysis of real application has been more likely based on a specific case to case resolution procedure that often requires a great effort in terms of modeling by the human operator. Moreover, limitations like the state space explosion for increasing number of components, the constrain of using exponential distribution for all kind of basic events constituting any analyzed system and the ineffectiveness of modularization for DFT which exhibit dynamic gates at top levels without incurring in calculation and methodological errors are faces of these methodologies. In this paper we present a high level modeling framework that exceeds all these limitations, based on Monte Carlo simulation. It makes use of traditional DFT systemic modeling procedure and by replicating the true casual nature of the system can produce relevant results with low effort in term of modeling and computational time. A Simulink library that integrates Monte Carlo and FT methodologies for the calculation of DFT reliability has been developed, revealing new insights about the meaning of spare gates.     

Design of a fault tolerant control system incorporating reliability analysis and dynamic behaviour constraints

In highly automated aerospace and industrial systems where maintenance and repair cannot be carried out immediately, it is crucial to design control systems capable of ensuring desired performance when taking into account the occurrence of faults/failures on a plant/process; such a control technique is referred to as fault tolerant control (FTC). The control system processing such fault tolerance capability is referred to as a fault tolerant control system (FTCS). The objective of FTC is to maintain system stability and current performance of the system close to the desired performance in the presence of system component and/or instrument faults; in certain circumstances a reduced performance may be acceptable. Various control design methods have been developed in the literature with the target to modify or accommodate baseline controllers which were originally designed for systems operating under fault-free conditions. The main objective of this article is to develop a novel FTCS design method, which incorporates both reliability and dynamic performance of the faulty system in the design of a FTCS. Once a fault has been detected and isolated, the reconfiguration strategy proposed in this article will find possible structures of the faulty system that best preserve pre-specified performances based on on-line calculated system reliability and associated costs. The new reconfigured controller gains will also be synthesised and finally the optimal structure that has the ‘best’ control performance with the highest reliability will be chosen for control reconfiguration. The effectiveness of this work is illustrated by a heating system benchmark used in a European project entitled intelligent Fault Tolerant Control in Integrated Systems (IFATIS EU-IST-2001-32122).     

基于故障树和规则匹配的故障诊断专家系统

当前对于设备的故障诊断专家系统,无论在设计上还是实现上,都受到很多客观因素的制约,使得专家系统的实用性和效率都受到了很大的影响。该文从实际应用的角度出发,在已有故障树诊断和规则推理诊断方法的基础上,提出了一种基于专家规则匹配的、可成长的故障诊断专家系统模型,并给出了基于该系统的推理算法和成长机制。该系统模型着重于提高诊断系统的效率和实用性,具有一定的通用性,并在实际项目中取得了较为成功的应用。     

一体化装置故障诊断及系统可靠性规划研究*

针对一体化装置的故障预测难题,提出了一体化装置故障诊断模型。通过对模型进行分析,找出系统主要的故障元素及各子系统的故障概率,根据系统可靠性理论,从提高系统可靠性的角度出发,提出了可靠性规划方法,以各个装置分配备用装置的顺序为阶段和装置间所允许使用的总备用个数为状态变量,对主要故障元素进行可靠性规划。最后通过仿真分析,大幅度提高了一体化装置的安全稳定性,结果表明了所提方法的可行性和有效性。     

Development of smart sensors system for machine fault diagnosis

Machine fault diagnosis is a traditional maintenance problem. In the past, the maintenance using tradition sensors is money-cost, which limits wide application in industry. To develop a cost-effective maintenance technique, this paper presents a novel research using smart sensor systems for machine fault diagnosis. In this paper, a smart sensors system is developed which acquires three types of signals involving vibration, current, and flux from induction motors. And then, support vector machine, linear discriminant analysis, k-nearest neighbors, and random forests algorithm are employed as classifiers for fault diagnosis. The parameters of these classifiers are optimized by using cross-validation method. The experimental results show that smart sensor system has the similar performance for applying in intelligent machine fault diagnosis with reduced product cost. Developed smart sensors have feasibility to apply for intelligent fault diagnosis.     

基于故障树的梭式窑故障诊断专家系统

为实现对梭式窑运行异常特别是燃烧异常的故障检测和定位,研究并设计了一种基于故障树的故障诊断专家系统。首先给出梭式窑故障诊断专家系统的形式化定义,进而详细分析并设计了专家系统的各个组成部分;最后重点介绍使用故障树来设计知识库的原理与方法,以及使用故障树来进行故障诊断推理的算法。工程实践表明,该系统知识模型适应性好,使用简单方便,故障诊断结果可靠稳定。     

基于Internet的故障树自动生成系统的研究

目前,计算机自动生成故障树技术的开发已经得到了广泛关注。为了增强故障树的可读性,简化大系统故障树生成的复杂性,并能够实现故障树生成技术的资源共享,本文介绍了一种基于Internet、利用JSP/Servlet技术的远程控制系统故障树生成系统的体系结构,并阐述了该体系结构下系统主要功能模块。最后,结合一个液位控制系统的例子验证了基于Inter-net的故障树生成系统的有效性和可行性。     

Development of a new automatic fault diagnosis system for fine pattern transmission lines

International Journal of Control, Automation and Systems - This paper presents a new automatic fault diagnosis and detection system for fine pattern interconnects. It is verified by performance of...     

故障树模块化在装甲车辆灭火系统故障诊断中的应用

为了实现装甲装备灭火系统故障的快速诊断,提出了一种故障树模块化分析方法;对灭火系统故障树进行深度优先最左遍历,并记录遍历过程,按照遍历顺序对故障树中的每个事件进行标定,并将灭火系统故障树划分为相互独立的模块,依据划分的模块可以通过故障现象对模块内的故障进行排查及修复;实验结果分析表明,该方法可以快速修复模块故障,恢复系统功能,简化了以往对灭火系统所有子事件遍历查错的繁琐过程。该方法同样可以计算故障模块的失效概率,并可以实现故障模块的整体更换,恢复系统性能;证明了故障树模块化方法在灭火系统故障诊断中具有较高的效率,简化了灭火系统诊断流程,在装甲车辆其他系统故障诊断中具有借鉴作用,符合现代作战对于装备保障的需求。     

Methodology for security analysis of data-processing systems

Use of the logic programming language PROLOG assists in tracking functional relationships through complex networks to ensure that all products receive a security classification consistent with the operative security model. The language also permits computing work factors for data products. In some cases, these work factors may modify the levels of protection required.     

一种基于航电系统架构模型的故障树自动建模方法

航电系统作为安全关键系统,利用故障树对其进行安全性分析十分必要。然而,传统的故障树依靠手工构建,主要依赖于分析人员对系统的理解程度;同时由于安全性分析人员与系统设计人员对系统的理解不同而很难保证失效模式与系统架构的一致性。针对上述问题,提出了一种基于航电系统架构模型的故障树自动建模方法:通过向系统设计模型中添加相应的安全性属性,并嵌入高级形式化语言AltaRica中的断言机制描述故障转移过程,由此形成安全性分析模型;基于此模型利用路径追溯的方法完成故障树自动建模。以某飞机驾驶舱显示系统为案例的研究结果表明,所提出的方法能基于航电系统架构模型有效进行故障树自动建模,从而确保了故障树分析结果的完整性。     

基于FFAT的装载机液压系统故障诊断

在分析装载机液压系统故障特征的基础上,建立了液压系统的故障树层次模型,针对故障树底事件和中间事件发生概率情况获取不足的现状,将模糊集合理论引入到故障树分析中,采用模糊数来刻画事件发生概率,利用模糊重要度来描述底事件对顶事件的影响,并以装载机液压系统中"工作泵"故障树为例进行了分析.结果说明,该方法具有较强的灵活性和适用性.