基于模糊故障树的液晶电视故障分析

针对液晶电视故障机理、故障原因的不确定性及模糊性,将模糊集理论引入其故障树分析中.建立了液晶电视模糊故障树,应用模糊运算法则对其进行定性分析及定量分析,计算出顶事件的模糊概率以及底事件的重要度.研究结果表明,该方法可以较好地解决液晶电视故障树分析中底事件故障判据的不确定性问题,为液晶电视的设计及故障诊断提供参考,对建立特定的液晶电视故障智能诊断系统非常有效.     

基于T-S模糊故障树模型的场面监视雷达磁控管的故障推理研究

针对机场监视雷达磁控管运行时间短、实时运行数据难以大量获得的特点,为了实现雷达收发系统磁控管的快速故障推理分析,提出一种基于T-S模糊故障树模型的故障推理方法。利用该方法能够定性分析与定量计算的突出特点,采用新疆某机场场面监视雷达磁控管作为研究对象,对磁控管的故障事件及其可能造成故障的各个故障事件用相应的事件代码表示,并通过模糊数语言集描述这些事件,再根据事件关系所构建的T-S模糊故障树故障推理模型进行推理分析,最后通过实验结果验证该方法的可靠性和有效性。与传统的人工故障排查方法相比,其能够对磁控管故障事件进行更加全面且高效的推理分析。该方法为磁控管的故障推理分析在工程上的实践应用提供了新思路。     

一种融合FTA与BAM的故障诊断方法

在研究故障树分析(FE气)和双向联想记忆(BAM)神经网络在故障诊断中应用的基础上,提出了一种融合FTA和BAM的故障诊断方法.故障树存贮了系统关于顶事件发生的全部知识,利用FTA得到系统所有的故障模式,进而归纳出BAM的学习样本,即故障树中故障现象(监测点状态组合)和底事件发生与否之间的对应.RAM通过联想记忆矩阵并行联想,得到诊断结果,扩展综合故障诊断能力.仿真结果表明该方法用于解决此类问题是有效的.     

电源技术

0530 充电与发电及其设备9908927水电站群装机容量分配的多目标模糊优化方法[刊]/李会安//西安理工大学学报.—1998,14(3).—289～293(G)9908928水轮发电机组的事故停机分析与故障诊断专家系统的研究[刊]/杨晓萍//西安理工大学学报.—1998,14(2).—201～205(B)构造了水轮发电机组的故障树,对故障树进行了定性定量分析,得出了逻辑分析与数量分析的结果,并对故障树的简化与等效进行了讨论;按照故障树模型,建立了在线故障数据采集和故障诊断的实时故障诊断专家系统,介绍了专家系统知识库的建立及知识表示方法。参4     

基于故障树的定向钻机故障诊断专家系统设计

针对目前矿用定向钻机故障依靠人工经验、处理速度慢等问题,文中提出一种基于故障树的定向钻机故障诊断专家系统。采用故障树分析,以矿用定向钻机泵站的典型故障构建故障树模型,通过故障树底事件的概率向上计算中间事件和顶事件的概率,进而获得底事件的概率重要度。根据故障树模型和产生式规则在SQL Server软件中建立专家知识库,储存专家处理故障的知识;再使用正向推理策略对推理机进行设计,通过产生式规则和故障树分析判断故障类型以及故障发生的概率。最后,通过Visual Studio软件开发故障诊断专家系统。经模拟测试,所设计的专家系统能够有效提高矿用定向钻机的故障诊断效率,并快速定位故障类型和原因,可为进一步研究钻机智能故障诊断和健康监测奠定基础。     

故障树分析法在半导体设备故障诊断中的应用

介绍了故障树分析法的原理.以反应离子刻蚀(RIE)设备的典型故障为例,建立故障树,通过求解最小实际故障来进行定性分析.尝试扩展故障树在故障判断和改进真空系统可靠性方面的应用,得出几个有针对性的结论.该方法能提高故障诊断的效率和准确性.     

基于故障树和神经网络的飞机电源系统故障诊断研究

介绍了基于故障树模型的故障诊断技术和基于神经网络的故障诊断技术，提出了基于故障树和神经网络的集成故障诊断思想。在此基础上，以交流发电机旋转整流器二极管开路故障为例进行了实例分析，说明了故障树和神经网络集成故障诊断技术对此故障的诊断，结果表明该方法用于解决此类问题是有效的。     

层次故障树分析法在装备故障诊断中的应用

综合分层法和故障树法,提出一种新的故障诊断方法,该方法利用装备在结构和功能上具有一定层次的特点进行结构和功能上的分解,将故障缩小在一定的功能范围内,然后利用故障树进行故障诊断和故障定位.该方法比较适合于对装甲装备进行故障诊断与定位,具有简洁、高效的特点.     

基于模糊故障树和VC的航海雷达发射机故障分析

本文主要是对航海雷达发射机故障进行分析.首先以雷达发射机故障为顶事件,建立了模糊故障树.然后请船舶行业的专家对基本事件发生的概率进行评估,通过三角模糊数确定了各个基本事件发生的概率.最后用VC＋＋6.0软件做出一个可以绘制模糊故障树并且可以进行定性和定量分析的系统,系统利用状态枚举法得到顶事件发生的三角模糊概率,同时系统还得到故障树的最小割集,劲集以及各个基本事件的模糊重要度,并对一些故障提出了诊断方法.     

基于虚拟仪器1553B总线模块故障诊断系统设计

分析1553B总线模块设计原理基础上,通过对1553B总线模块故障树的定性和定量分析,构建基于故障树的故障诊断系统.描述基于虚拟仪器技术的故障诊断系统实现方案并设计相应的单元测试集,提高故障定位的精确度.     

Dynamic fault dictionaries and two-stage fault isolation

This paper presents dynamic two stage fault isolation for sequential random logic VLSI circuits, and introduces limited and dynamic fault dictionaries. In the first stage of the dynamic process, a limited fault dictionary identifies candidate faults, which are further distinguished in the second stage by a dictionary generated dynamically for the candidate faults and a subset of the test vectors. This provides high resolution but avoids the costs of full static dictionaries. Two-stage fault isolation is evaluated for benchmark circuits and on defects in industrial circuits     

NFV故障关联及故障自愈方案研究

利用NFV实现电信网络设备软硬件解耦,摆脱了对专用硬件设备的依赖,并能利用NFV资源共享、自动部署、弹性伸缩等特性,但同时也带来了故障点多、故障定位分析困难等问题,导致NFV网络的运营维护难度增加。分析了NFV故障处理的流程及故障关联方案,为NFV场景下的故障定位处理提供指引。同时给出了VNF故障自愈实现方案,利用VNF特性,实现网元及业务自愈,提升自动化运维能力。     

Implicit deductive fault simulation for complex delay fault models

This paper introduces an implicit version of the well-known deductive fault simulation technique suitable to delay fault models with an exponential number of faults. The proposed method calculates the fault coverage by generating lists of entities for each line during a single topological circuit traversal. Each stored entity only contains a number and a subset of the test vectors. No delay faults are stored, and no special data structures are required. There are significant differences between the presented implicit method and fault coverage using deductive fault simulation. The method is shown to be effective for delay the path and segment delay fault models.     

Statistical estimation of delay fault detectabilities and fault grading

In this paper we present a technique to statistically estimate transition delay and path delay fault coverage. The basic method is an extension of STAFAN to include delay faults. By partitioning a combinational circuit into non-overlapping fanout free logic cones, we accurately calculate the transition sensitization controllabilities of 0 1 and 1 0 transitions of the lines within a fanout free logic cone to the output of the fanout free logic cone for each fanout free logic cone. A strategy to calculate the transition observabilities of fanout stems is proposed. The detectability of a path delay fault is evaluated as the product of the observabilities of the input line to its head gate within each fanout free logic cone on the path multiplied by the transition controllability of the path. When compared with the fault simulations, the estimations of transition delay fault coverage are within 2.3%. Also, the technique gives reasonably good path delay fault coverage estimation for large fault set of the ISCAS85 benchmark circuits.     

Classification of fault trees and algorithms of fault tree analysis

A new classification of fault trees is proposed, and the relationship between the new and old classifications is discussed. The new classification is illustrated with an example, and the limitation of the well-known simple prime implicant algorithm, which can work on fault trees, is shown. Thus a general unified algorithm for computer-aided fault tree analysis is presented.     

一款蓝牙车载免提故障的维修--免提喇叭无声的故障的维修

主要描述了一款蓝牙车载免提的故障维修。该蓝牙车载蓝牙部分电路主要使用了CSR蓝牙芯片,回音处理部分电路主要使用了Fortemedia公司的FM1073.主要描述了该免提的基本原理以及一种无声的故障的修理。     

Large-scale fault isolation

Of the many distributed applications designed for the Internet, the successful ones are those that have paid careful attention to scale and robustness. These applications share several design principles. In this paper, we illustrate the application of these principles to common network monitoring tasks. Specifically, we describe and evaluate 1) a robust distributed topology discovery mechanism and 2) a mechanism for scalable fault isolation in multicast distribution trees. Our mechanisms reveal a different design methodology for network monitoring-one that carefully trades off monitoring fidelity (where necessary) for more graceful degradation in the presence of different kinds of network dynamics     

Statistical fault sampling

Computational requirements often discourage, or even prohibit, complete fault simulation of circuit designs having greater than 20000 single stuck-at faults. To circumvent this problem, statistical sampling methods have been proposed that provide fault coverage values within a small, predictable error range by simulating only a fraction of the circuit's total faults and using the result fault coverage value as an estimate of the fault coverage for the total circuit. As an introduction to the application of sampling methods to fault simulation of integrated circuits, the statistical theory behind these sampling methods and proposed augmentations of these methods for improving the precision of the sample fault coverage are presented. Various proposed sampling schemes are applied to example circuit designs, and the results are analyzed     

Parallel-concurrent fault simulation

A new parallel-concurrent fault simulation algorithm based on the partitioning of faults into groups, with the group size equal to the number of bits in the host computer word, is presented. The fault effects of a particular group are evaluated using parallel fault simulation techniques and propagated using concurrent fault simulation techniques. The speed of the algorithm depends on the circuit and on the fault-grouping criterion. An automatic grouping criterion is devised to group faults that are “close” or nearly equivalent. Comparisons to the concurrent, to the deductive, and to the PROOFS fault simulation techniques are performed on a SPARC SLC with 16 MB of memory running UNIX. ISCAS89 benchmark circuits are used for this comparison