模拟电路故障诊断可信度研究

提出了描述标称转移矩阵Ｚ０的各标征向量几何分布性状的Ｖｏｒｏｎｏｉ多胞体，定义了描述测量向量ｄＵ在标征向量Ｚｉ中位置的标征干扰角θｕｉ。然后利用这两个概念揭示了容差─故障电路可诊充要和充分条件，讨论了定位故障的极值法和阈值法的有效性、局限性，及提高定位准确率的可能途径。     

A Low-Cost Fault-Tolerant Structure for the Hypercube

We propose a new, low-cost fault-tolerant structure for the hypercube that employs spare processors and extra links. The target of the proposed structure is to fully tolerate the first faulty node, no matter where it occurs, and almost fully tolerate the second, meaning that the underlying hypercube topology can be resumed if the second faulty node occurs at most locations—expectantly 92% of locations. The unique features of our structure are that (1) it utilizes the unused extra link-ports in the processor nodes of the hypercube to obtain the proposed topology, so that minimum extra hardware is needed in constructing the fault-tolerant structure and (2) the structure's node-degrees are low as desired—the primary and spare nodes all have node-degrees of n + 2 for an n-dimensional hypercube. The number of spare nodes is one fourth of primary nodes. The reconfiguration algorithm in the presence of faults is elegant and efficient. The proposed structure also effectively enhances the diagnosability of the hypercube system. It is shown that the diagnosability of the structure is increased to n + 2, whereas an ordinary n-dimensional hypercube has diagnosability n.     

多工位装配过程中测量方案的研究

为保证产品质量并适应企业信息化发展的需要,对多工位装配过程中测量方案的优化问题进行了研究.文中基于状态空间方程建立了多工位装配过程中的误差传递模型,用以反映过程中不同工位上的误差信息和测量信息,并提出了诊断能力的概念来度量该测量方案的执行能力,在上述基础上得到一种优化方法来构建具有完全诊断能力的优化测量方案.最后,以一个三工位薄壁件装配过程为例进行了说明和验证.     

Comparative analysis of related notions of robust diagnosability of Discrete-Event Systems

In this paper, we revisit the problem of robust diagnosability of Discrete-Event Systems (DES), and present a comparative analysis between the following notions of robust diagnosability existing in the literature: (i) diagnosability of DES subject to permanent sensor failures, assuming that sensors may fail only before the first occurrence of the events they are supposed to record; (ii) diagnosability of DES subject to permanent sensor failures, assuming that sensors may fail at any time; (iii) diagnosability of DES against intermittent loss of observations; (iv) diagnosability of partially observed DES; (v) generalized robust diagnosability. We show that all of the robust diagnosability definitions are particular cases of the generalized robust diagnosability by presenting transformation mechanisms for each one of the analyzed robust diagnosability notions so as to convert it into an equivalent generalized robust diagnosability problem. We also compare the use of projections and masks in the context of language diagnosability and show that there is no loss of generality in using projections in place of masks by presenting a map that transforms the language diagnosability problem with observation mask into an equivalent one with projection.     

Conditional diagnosability of hypermeshes under the comparison model

The hypermeshes are a family of promising optical interconnection topologies for multiprocessor systems. This paper is concerned with the conditional diagnosability of hypermeshes under the comparison model. We prove that, for n?3, k?4, the conditional diagnosability of kn-hypermesh is 3n(k−1)−2k−1. This result shows that the hypermeshes possess strong self-diagnosing ability.     

Assembly Root Cause Analysis: A Way to Reduce Dimensional Variation in Assembled Products

The objective of root cause analysis (RCA) is to make the trouble shooting dimensional error efforts in an assembly plant more efficient and successful by pinpointing the underlying reasons for variation. The result of eliminating or limiting these sources of variation is a real and long term process improvement. Complex products are manufactured in multileveled hierarchical assembly processes using positioning fixtures. A general approach for diagnosing fixture related errors using routine measurement on products, rather than from special measurements on fixtures, is presented. The assembly variation is effectively tracked down into variation in the fixture tooling elements, referred to as locators. In this way, the process engineers can focus on adjusting the locators affected by most variation. However, depending on the assembly process configuration, inspection strategy, and the type of locator error, it can be impossible to completely sort out the variation caused by an individual locator. The reason for this is that faults in different locators can cause identical dimensional deviation in the inspection station. Conditions guaranteeing diagnosability are derived by considering multiple uncoupled locator faults, in contrast to previous research focusing on single or multiple coupled locator faults. Furthermore, even if an assembly is not diagnosable, it is still possible to gain information for diagnosis by using a novel approach to find an interval for each locator containing the true underlying locator variation. In this way, some locators can be excluded from further analysis, some can be picked out for adjustment, and others remain as potential reason for assembly variation. Another way around the problem of diagnosability is to make a higher level diagnosis by calculating the amount of variation originating from different assembly stations. Also, a design for diagnosis approach is discussed, where assembly and inspection concepts allowing for root cause analysis are the objective.     

系统级概率故障诊断的最小测试数

系统级故障诊断中的核心问题，是要用最小的开销完成诊断任务，由于测试数是诊断开销的一部分，希望测试数达到最小，在几种概率测试模型下，我们给出了概率诊断中最小测试数的上界和下界，这两个界具有同一数量级。