多攻击线引起的串扰时延故障的TPG

探讨了一种串扰时延最大化算法,并且利用被修改的FAN算法,生成测试矢量.对于一条敏化通路,利用被修改的FAN算法适当地激活相应的攻击线和受害线,使电路在最恶劣情况下引起最大通路时延,从而实现更有效的时延测试.利用了FAN算法的多路回退和回溯等主要特色,提高了测试生成算法的效率.实验结果表明,沿着任何临界通路传播的受害线相耦合的攻击线被适当地激活,并且可以对一定规模的电路的串扰时延故障进行测试矢量生成.     

Deterministic BIST with Multiple Scan Chains

A deterministic BIST scheme for circuits with multiple scan paths is presented. A procedure is described for synthesizing a pattern generator which stimulates all scan chains simultaneously and guarantees complete fault coverage.The new scheme may require less chip area than a classical LFSR-based approach while better or even complete fault coverage is obtained at the same time.     

动态向量调整的多扫描链测试数据压缩

 由于多扫描链测试方案能够提高测试进度,更适合大规模集成电路的测试,因此提出了一种应用于多扫描链的测试数据压缩方案.该方案引入循环移位处理模式,动态调整向量,能够保留向量中无关位,增加向量的外延,从而提高向量间的相容性和反向相容性;同时,该方案还能够采用一种有效的参考向量更替技术,进一步提高向量间的相关性,减少编码位数.另外,该方案能够利用已有的移位寄存器,减少不必要的硬件开销.实验结果表明所提方案在保持多扫描链测试优势的前提下能够进一步提高测试数据压缩率,满足确定性测试和混合内建自测试.     

红外热像的初始化诊断法

简述通常采用的热平衡后摄取红外热像进行故障诊断所带来的问题和针对该问题所作的试验，试验结果表明初始化诊断法可以有效地抑制通过热传导、热辐射、热对流方式对被测元器件相互间的影响，从而使诊断准确、迅速。     

一种精确计算容差网络的新算法

论述了应用Markov区间迭代法对含有容差的网络进行节点电压分析。文中首先介绍Markov区间选代法的基本方法，然后把这种方法应用于容差网络的节点电压计算，并把计算结果与Hansen迭代法进行比较。结果表明，这种方法具有较高的计算精度，它不仅能够用于电路的分析而且也能够用于容差网络的故障诊断。     

一种基于多重模糊有向图的系统划分方法

在系统级测试性设计中,为了实现模块间合理划分,采用多重模糊有向图表示系统模块间的故障传播关系,并在此基础上实现了系统划分。该划分方法不仅充分考虑了系统可测性设计要求,而且将同一模块上的固有故障传播和传递得到的故障分开分析,建立更加接近实际的故障传播影响度矩阵,与其他方法相比,该方法更加贴近模块间故障影响的真实情况,能够实现更精确的系统划分。     

Multiple Experiment Environments for Testing

Concurrent simulation (CS) has been used successfully as areplacement for serial simulation. Based on storing differences fromexperiments, CS saves storage, speeds up simulation time and allowsexcellent internal observation of events. In this paper, we introduceMultiple Domain Concurrent Simulation (MDCS) which like concurrentsimulation, maintains efficiency by only simulating differences. MDCS alsoallows experiments to interact with one another and create new experimentsthrough the use of domains. These experiments can be traced and observed atany point, providing insight into the origin and causes of new experiments.While many experiment scenarios can be created, MDCS uses dynamic spawningand experiment compression rather than explicit enumeration to ensure thatthe number of experiment scenarios does not become exhaustive. MDCS does notrequire any pre-analysis or additions to the circuit under test. Providingthis capability in digital logic simulators allows more test cases to be runin less time. MDCS gives the exact location and causes of every experimentbehavior and can be used to track the signature paths of test patterns forcoverage analysis.We will describe the algorithms for MDCS, discuss the rules forpropagating experiments and describe the concepts of domains for makingdynamic interactions possible. We will report on the effectiveness of MDCSfor attacking an exhaustive simulation problem such as Multiple Stuck-atFault simulations for digital logic. Finally, the applicability of MDCS formore general experimentation of digital logic systems will be discussed.     

基于动态权值的多分类器故障诊断系统

 为提高动态系统故障诊断的精确性,以及减少系统运行环境对故障诊断带来的影响,本文提出了一种基于动态权值的多分类器故障诊断系统.该方法使用决策支持度来衡量当前诊断任务中各分类器的实时决策可信度,并将其联合分类器性能指标动态地为各分类器赋予融合权值,决策性能好且决策支持度高的分类器决策结果获得较大的融合权值,同时,使不可靠决策结果的融合权值趋近于零.在此基础上,将多分类器系统优化为实时性能较好的分类器组成的子系统进行故障诊断,减少了不可靠决策的干扰,进一步提高了融合决策的精确度.试验表明本文方法具有良好的诊断决策性能,能获得比单个分类器和常用的一些融合算法更高的分类准确度.     

电控机械式自动变速器在线故障诊断系统的开发

根据电控机械式自动变速器系统的特点,采用基于模型的设计方法,在MATLAB／SIMUuNK软件环境下,运用Stateflow逻辑系统建模工具建立了AMT系统的在线故障诊断模型,从而有效地对AMT系统中的传感器、执行机构和TCU硬件的主要故障进行在线诊断。大量试验表明,该设计方法是行之有效的且非常实用。     

基于模糊动态博弈的多无人机空战策略研究

不确定环境下多无人机空战决策问题已成为无人机作战系统的一个重要研究课题。首先通过分析无人机空战态势信息的不确定性, 建立模糊信息下的多无人机动态博弈的作战优势函数; 将动态扩展式博弈转化成静态策略式博弈, 构建基于模糊信息的双方博弈的支付矩阵。将模糊结构元方法和粒子群算法相结合, 给出模糊信息下动态博弈的混合战略的纳什均衡求解方法。最后通过仿真实验验证了该方法的可行性和有效性。     

An Isochronous Testing Strategy for Hierarchical Adaptive Distributed System-Level Diagnosis

Distributed System-level diagnosis allows the fault-free components of a fault-tolerant distributed system to determine which components of the system are faulty and which are fault-free. The time it takes for nodes running the algorithm to diagnose a new event is called the algorithm's latency. In this paper we present a new distributed system-level diagnosis algorithm which presents a latency of O(log N) testing rounds, for a system of N nodes. A previous hierarchical distributed system-level diagnosis algorithm, Hi-ADSD, presents a latency of O(log ² N) testing rounds. Nodes are grouped in progressively larger logical clusters for the purpose of testing. The algorithm employs an isochronous testing strategy that forces all fault-free nodes to execute tests on clusters of the same size each testing round. This strategy is based on two main principles: a tested node must test its tester in the same round; a node only accepts tests according to a lexical priority order. We present formal proofs that the algorithm's latency is at most 2log N – 1 testing rounds and that the testing strategy of the algorithm leads to the execution of isochronous tests. Simulation results are shown for systems of up to 64 nodes.     

自适应光学波前处理器的故障诊断系统设计

为了及时发现及定位基于FPGA(Field Programmable Gate Arrays)的自适应波前处理器执行过程中发生的问题, 提出一种针对该波前处理器的故障诊断系统以解决这一问题。根据调试及操作的需求, 该系统能够向上位机实时反馈当前波前处理各部分的执行结果及运行状态, 定位故障并分析数据误差。该系统在137单元波前处理器实验平台上进行了实验, 实验结果表明: 在处理器实时校正过程中, 监控系统反馈的数据及相关信息与相应理论值能够很好地匹配, 能及时发现故障并定位。该系统应用于大型地基高分辨率成像望远镜的自适应光学系统, 直观反映自适应光学波前处理器的运行过程及相应结果, 如发生故障, 可以及时发现并定位故障来源, 较大地提高了硬件及软件的调试效率。同时, 通过各阶段运行结果的分析, 有利于进一步提高各部分运算速度及精度。     

基于距离分析的多性能参数故障预测方法

目前,基于性能退化数据的可靠性分析已成为有效而节约成本的可靠性评估方法,现有关于此方面研究的文献大多局限于研究单特征量的情形,而许多产品具有多个性能退化量。针对产品具有多个性能参数的特点,提出了基于多参数距离分析的可靠性分析方法,探讨并提出多性能参数距离、距离失效阈值的概念,给出参数加权因子的求解方法。弥补了现有方法基于多元正态联合概率密度函数假设致使求解过程较复杂等不足。最后通过仿真实例验证了方法的有效性。     

多天线双向中继转发的优化方法研究

本文对多天线双向中继放大转发方案进行了研究。首先,基于最小化均方误差的准则,通过对上行链路和下行链路进行联合优化,推导出了相应的中继优化方法,该优化方法能够实现最优的链路可靠性。然后,基于该优化方法,利用部分信道状态信息和信道统计信息,针对固定中继和移动中继两种不同的通信场景,分别设计了不同参数控制下的鲁棒性实现。理论分析和计算机仿真都表明所提方案具有明显的性能增益。      

A Combined Clustering and Neural Network Approach for Analog Multiple Hard Fault Classification

A new neural network-based fault classification strategy for hard multiple faults in analog circuits is proposed. The magnitude of the harmonics of the Fourier components of the circuit response at different test nodes due to a sinusoidal input signal are first measured or simulated. A selection criterion for determining the best components that describe the circuit behaviour under fault-free (nominal) and fault situations is presented. An algorithm that estimates the overlap between different faults in the measurement space is also introduced. The learning vector quantization neural network is then effectively trained to classify circuit faults. Performance measures reveal very high classification accuracy in both training and testing stages. Two different examples, which demonstrate the proposed strategy, are described.     

基于GA-DS的多神经网络故障诊断方法

针对基于信息熵的神经网络证据形成过程需要专家经验确定参数这一不足,提出一种改进方法,即用遗传算法(Genetic Algorithm,GA)进行寻优,自动确定参数,其实质是利用了遗传算法的高效的并行寻优能力和对初始种群的较低的敏感性,通过训练样本自适应调整证据形成过程中的参数,提升DS(Dempster Shafer)证据理论的融合效率.对多类轴承故障数据的诊断结果表明,该方法(GA-DS)能够自动调整神经网络的证据形成过程,从而有效地降低了融合过程中证据的冲突性,并且显著提高了诊断精度和稳定性.     

适用于嵌入式五口SRAM的多频率内建自测电路

提出了一种多频率带有扫描链的 BIST方案 ,用于五口的 32× 32嵌入式 SRAM的可测性设计。分析了多口 SRAM的结构并确定其故障模型 ,在此基础上提出了一种名为“对角线移动变反法”( OMOVI)的新算法及其电路实现。与传统的“移动变反法”( MOVI)相比 ,在保证故障覆盖率前提下 ,测试图形的测试步数由原来的12 N log2 N减小为 N/ 2 +2 N log2 N( N为 SRAM的容量 )。该方案集功能测试、动态参数提取和故障分析定位于一体 ,而且具有很强的灵活性和可扩展性     

SNR Enhancement Algorithm Using Multiple Chirp Symbols with Clock Drift for Accurate Ranging

A signal‐to‐noise ratio (SNR) enhancement algorithm using multiple chirp symbols with clock drift is proposed for accurate ranging. Improvement of the ranging performance can be achieved by using the multiple chirp symbols according to Cramer‐Rao lower bound; however, distortion caused by clock drift is inevitable practically. The distortion induced by the clock drift is approximated as a linear phase term, caused by carrier frequency offset, sampling time offset, and symbol time offset. SNR of the averaged chirp symbol obtained from the proposed algorithm based on the phase derotation and the symbol averaging is enhanced. Hence, the ranging performance is improved. The mathematical analysis of the SNR enhancement agrees with the simulations.     

线性容差电路的K故障模糊屏蔽定位

研究了线性电路的等输入／等输出Ｋ故障屏蔽方法在容差情况下的应用，提出了故障隶属函数，用以定位故障元件或模糊故障集，从而大幅度地降低了故障与容差之间的模糊性，提高了Ｋ故障屏蔽法的实用性。对算法进行了详尽的研究，测后计算量小。     

基于粗糙集的CBR系统案例检索策略

针对案例推理系统中案例检索的效率和质量问题,提出一种新的案例检索策略.采用粗糙集进行案例属性约简,完成案例库优化,并计算反映专家经验的属性权重,结合相似度计算和人工神经网络进行不同情况下的案例检索.运用UCI数据集进行了仿真对比,将其用于数字数据网故障诊断系统中,结果表明所提出的策略在不同数据集下均具有较高的检索效率,更加适用于实际CBR系统.