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基于信息融合的诊断贝叶斯网络研究 总被引:1,自引:1,他引:0
针对设备故障诊断技术中存在的固有不确定性问题,通过分析传统故障树模型存在的局限性以及传统贝叶斯网络建造困难的特性,提出了一种融合于故障树和传统贝叶斯网络的新方法--诊断贝叶斯网络,并阐述了故障树和贝叶斯网络的故障诊断策略优化方法的基本思想和具体算法.通过比较分析,综合考虑了故障树和贝叶斯网络在诊断推理和模型表达方面的特点及仿真结果,提出的新方法可以使二者优势充分发挥,在故障诊断领域中具有实际的应用价值. 相似文献
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空间机械臂在空间设施中广泛应用,如何准确快速判断其运行状态成为需要解决的重要问题。文中首先介绍了机械臂在国内外空间设施的应用背景,然后采用基于故障树与贝叶斯网络的故障诊断方法,包括:基于系统组成结构的故障树建模、贝叶斯网络转化、团树传播算法和最大后验估计(MAP)推理结果分析。最后利用单点故障实验和多点故障实验对所提方法进行了验证,结果表明将故障树分析和贝叶斯网络结合应用到空间机械臂故障诊断是有效的、可行的。 相似文献
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为解决柴油机润滑系统多故障的解耦与诊断问题,提出一种基于贝叶斯网络模型的故障诊断方法.建立的润滑系统贝叶斯网络诊断模型包括利用有向无环图描述多故障耦合关系和采用概率形式表示故障诊断定量知识两个部分.按照故障类型将润滑系统故障诊断任务分解为各类故障的诊断子任务,对于各子任务,利用故障树模型分析故障与征兆及多故障间的耦合关系,并通过故障树向贝叶斯网络的转化建立润滑系统的贝叶斯网络模型结构.在定量参数方面,采用noisy-OR/AND模型分析故障与征兆间的因果关联强度,通过设定故障的先验发生概率描述润滑系统的历史运行状况.最后,通过两起“进机油压过低”故障实例验证所提出方法的有效性. 相似文献
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列控系统非常复杂,在对其进行故障分析时,自身的特质决定了用传统的故障树在对其进行故障分析时会产生局限性;为此文中引入了贝叶斯网络技术,充分利用其推理算法成熟、理论基础非常完备、学习能力非常强的优势,将事件树中各环节的故障树用贝叶斯网络进行描述;利用贝叶斯网络工具箱(BNT)对列车超速故障进行因果和诊断推理分析,通过数值计算结果得出所在不同场景下故障发生的主要原因,并提出减少故障发生概率相应的措施。 相似文献
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高速铁路控制系统的安全性评估非常重要,引入贝叶斯网络技术,充分利用传统事件树、故障树的分析优势,将事件树中各安全环节的故障树分别转化为贝叶斯网络,并按逻辑关系最终融合为一张完整的贝叶斯网.通过整合的贝叶斯网络不仅可以分析列控系统的安全性,同时还能得出其他有用的概率推理信息. 相似文献
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针对堆垛机设备在运行过程中呈现的复杂性、不确定性等问题,设计了基于故障树和贝叶斯网络的混合诊断专家系统。采用故障树分析技术对堆垛机进行故障建模,得到最小割集,建立了以规则为知识表示形式的规则库。根据输入的故障征兆系统自动寻找匹配的故障事实库,建立了以该事件作为顶事件的故障树,并转化得到相应的贝叶斯网络,形成了基于规则的推理和贝叶斯网络的概率计算混合诊断机制。该方法有效利用了故障树分析和贝叶斯网络两种算法的优势,为复杂机器的故障诊断提供了一种新途径。试验表明,该系统有效解决了传统诊断专家系统存在的推理模式单一、知识获取困难等问题。概率计算混合诊断机制是一种快速诊断堆垛机的可行方式。 相似文献
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Sensor networks are finding significant applications in large scale distributed systems. One of the basic operations in sensor networks is in-network aggregation. Among the various approaches to in-network aggregation, such as gossip and tree, including the hash-based techniques, the tree-based approaches have better performance and energy-saving characteristics. However, sensor networks are highly prone to failures. Numerous techniques suggested in the literature to counteract the effect of failures have not been carefully analyzed. In this paper, we focus on the performance of these tree-based aggregation techniques in the presence of failures. First, we identify a fault model that captures the important failure traits of the system. Then, we analyze the correctness of simple tree aggregation with our fault model. We then use the same fault model to analyze the techniques that utilize redundant trees to improve the variance. The impact of techniques for maintaining the correctness under faults, such as rebuilding or locally fixing the tree, is then studied under the same fault model. We also do the cost-benefit analysis of using the hash-based schemes which are based on FM sketches. We conclude that these fault tolerance techniques for tree aggregation do not necessarily result in substantial improvement in fault tolerance. 相似文献
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Raquel Barco Luis Díez Volker Wille Pedro Lázaro 《Expert systems with applications》2009,36(1):489-500
In the last years, self-organization of cellular networks is becoming a crucial aspect of network management due to the increasing complexity of the networks. Automatic fault identification, i.e. diagnosis, is the most difficult task in self-healing. In this paper, a model based on discrete bayesian networks (BNs) is proposed for diagnosis of radio access networks of cellular systems. Normally, inaccuracies are unavoidable in the parameters of the model (interval limits for discretized symptoms and probabilities in the BN). In order to enhance the performance of BNs, a methodology to model the “continuity” in the human reasoning is presented, named smooth bayesian networks (SBNs). SBNs are intended to decrease the sensitivity of diagnosis accuracy to imprecision in the definition of the model parameters. An empirical research campaign has been carried out in a live GSM/GPRS network in order to assess the performance of the proposed techniques. Results have shown that SBNs outperform traditional BNs when there is inaccuracy in the model parameters. 相似文献
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Fault diagnosis of power electronic system based on fault gradation and neural network group 总被引:1,自引:0,他引:1
We propose a new fault diagnosis approach with fault gradation using BP (back-propagation) neural network group consisting of 3 sub BP neural networks. According to the hazard extents and the occurrence frequencies of different faults, the faults are divided into different grades. The higher the fault grade, the larger the number of the used sub neural networks is. Experimental results show that our approach makes the correctness rate of the fault diagnosis rise greatly (from less than 95.0% to 99.5%) and the performance of the whole fault diagnosis system gets much better especially for the on-line complex systems. The approach proposed in this paper also can be extended to other complex fault diagnosis systems, such as mechanical systems. 相似文献
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为解决新装备故障分析与排除训练缺乏手段的问题,以开发某新型装备的故障排除训练系统设计为研究目标,运用故障树分析(FTA)方法,构建了重要分系统的故障树模型;通过对系统的功能需求分析,设计了系统运行的流程,构建了故障分析与排除系统的硬件结构;利用LabView平台开发出某新型装备的故障设置与排除训练系统;系统运行结果表明:满足了设计的功能需求,为维修保障训练中的故障分析与排除提供了方法手段和平台支持。 相似文献
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基于多级模糊神经网络的故障诊断在化工生产过程中的应用 总被引:5,自引:0,他引:5
化工生产过程一般都非常复杂,如柠檬酸蒸发。由于控制回路与测控参数很多,生产过程的故障检测与诊断问题非常困难,难以做到实时检查,得到其故障信息。所以本文提出一种基于神经网络的多级故障诊断系统。采用三级递阶模糊神经网络,降解整个系统故障诊断问题的复杂性,同时采用所有子神经网络全局并行的推理方式,具有快速处理能力,适合系统实时在线故障诊断。 相似文献
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近年来,概率逻辑学习研究取得了很大进展,已经提出各种不同的形式化方法和学习方法,包括概率关系模(PRMs)、贝叶斯逻辑程序(BLPs)、逻辑贝叶斯网络(LBNs)和随机逻辑程序(SLPs)等。文章重点介绍了贝叶斯网络与一阶逻辑的结合,并以PRMs、BLPs和LBNs为例,描述了基于贝叶斯网络的概率逻辑模型(PLMs)的知识表示方法,给出了此类PLMs一般使用的参数估计方法和结构学习方法,并给出了建议的研究方向。 相似文献