模拟电路故障的一种聚类二叉树支持向量机诊断新方法

针对模拟电路故障特征样本的分类(诊断)问题.提出了一种基于聚类二叉树支持向量机(SVMs)多分类器的故障诊断新方法,并分析了几种分类器的平均测试复杂度.首先,利用自组织特征映射神经网络(SOFM)对训练样本进行层次聚类.得到一棵聚类二叉树;其次,按照树的结构利用二元SVMs设计故障分类器,并对样本进行分组训练和测试.实际仿真和测试表明.所设计的故障分类器性能在诊断精度和效率上皆优于传统的"1-v-r"SVMs和"1-v-1"SVMs分类器,较为适合模拟电子电路的故障分类和诊断.     

一种基于SVR的发动机多模式故障诊断方法

针对传统基于支持向量分类机(SVC)的发动机多模式故障诊断方法需要多个二类分类器的问题,提出了一种基于支持向量回归机(SVR)的多模式故障诊断方法。该方法首先应用归一化的故障数据样本和一个支持向量回归机构建一个发动机故障诊断回归模型,再对支持向量回归机的输出结果进行基于距离的聚类操作得到发动机的故障模式,诊断模型的参数向量采用一种基于Tent混沌映射的量子粒子群优化算法及样本测试集的均方根误差与平均相对误差同时最小的准则进行整定。实验结果表明,所提出的方法能够克服常规支持向量分类机多模式故障诊断方法需要多个二类分类器的缺陷,降低了建模的时间复杂度,有效地提高了发动机的故障诊断性能。     

基于支持向量机的车用燃料电池系统故障诊断

为了提高车用燃料电池系统的安全可靠性和可维护性,考虑到其大量完整的故障样本难以获取,提出了一种基于二叉树多分类器的支持向量机故障诊断方法.首先,以自主研发的60 kW车用燃料电池系统为研究对象,分析了其故障机理和特征;然后,融合15种故障征兆参数并进行归一化预处理作为支持向量机的输入,以14种典型故障作为输出,选取径向基核函数并利用粒子群优化算法对支持向量机的惩罚参数和核函数参数进行优化,利用310组样本数据对其进行训练,通过90组测试样本测试实现了其典型故障的识别;最后,将支持向量机和神经网络分别在不同训练样本数下的故障诊断性能进行了对比.仿真结果表明,支持向量机具有较好的故障正判率和泛化能力,可有效用于车用燃料电池系统的多故障诊断.     

兼顾后续分类器的小波特征选择及在模拟电路故障诊断中的应用

针对模拟电路故障诊断中的特征选择问题,提出了一种兼顾后续支持向量机分类器的小波特征选择技术。新方法利用核函数把特征的评估标准映射至高维空间进行计算,从而在特征的评估和后续支持向量机分类器之间建立联系,并在特征选择阶段解决了核函数的参数设计问题。另外,新方法考虑了所需故障分类器的结构信息,因此选择的小波特征更适合后续分类器使用,从而能够提高模拟电路故障的诊断精度。仿真和实际电路的实验结果均验证了所提出技术的有效性和正确性。     

基于可测性分析和支持向量机的模拟电路故障诊断

针对低可测性模拟电路的测试问题,提出了一种模拟电路故障诊断的新方法.该方法首先计算被测电路的可测性,利用可测性提供的信息对被测电路进行模糊组划分,组成可诊断的元件集,并引入支持向量机完成对故障的分类识别.可测性分析理论上确定了被测电路可诊断的元件集,支持向量机结构简单,泛化能力强,以模拟和混合信号测试标准电路的实验结果证明了基于可测性分析和支持向量机的模拟电路故障诊断方法是有效的,其故障诊断率大于99%.     

SVM结合OCSVM诊断模拟电路故障

基于支持向量机(SVM)的故障诊断方法是当前主要的模拟电路故障诊断方法之一,但由传统的二分类SVM组成的故障分类器对新故障模式缺乏处理能力。针对该问题,提出了结合单类支持向量机(OCSVM)和SVM的故障诊断方法。该方法采用OCSVM对故障数据进行检测和初步分类,采用SVM来提高分类性能;最后,采用脉宽调制电路进行故障诊断实验,实验结果说明了所提出的故障诊断方法的有效性。     

基于支持向量机集成的模拟电路故障诊断

为了解决模拟电路故障诊断复杂多样难于辨识的问题,有效提高分类的准确度,提出了一种支持向量机集成的故障诊断方法.首先,该方法对采集信号进行Haar小波变换,提取1~5层小波变换的每层第1个低频系数构成特征集.然后将特征集输入集成支持向量机,实现对不同故障类型进行识别.将该方法应用于Sallen-Key带通和4运放双二次高通滤波电路进行故障诊断实验,结果表明,该方法比单一支持向量机、径向基神经网络、BP神经网络和集成K-NN分类器有更好的分类和泛化性能,故障诊断准确率更高.     

基于自适应小波分解和SVM的模拟电路故障诊断

为了降低模拟电路参数故障的测试难度,提出了基于自适应小波分解和SVM的模拟电路故障诊断的新方法,该方法对电路故障响应进行小波分解提取最优故障特征,母小波的选择是根据被测电路的正常响应和故障响应小波系数之差的最大均方根原则,并引入支持向量机对故障进行分类识别.小波分解具有自适应性,支持向量机结构简单,泛化能力强.实验结果证明了所提的基于自适应小波分解和SVM的模拟电路故障诊断方法是有效的,其故障诊断率大于96.8%.     

基于SVM的模拟电路故障特征识别方法

针对目前模拟电路测试性设计中,故障模式分析缺乏科学数据支持的问题,提出在特征提取的基础上,利用支持向量机(SVM)解决模式分类问题的基本原理,构造SVM分类器,对电路特征进行识别、分类的方法.经过仿真验证,该方法对模拟电路故障模式的识别、分类效果显著.     

基于最小二乘支持向量机的电力变压器故障诊断

文章提出使用最小二乘支持向量机(LS-SVM)作为分层决策电力变压器故障诊断模型.首先根据DGA技术以及相关统计分析,选择典型油中故障气体的相对含量作为特征量,然后利用数值预处理后得到的数据样本分别对四级最小支持向量机分类器进行训练和识别,并最后判断输出变压器所处的状态,且针对最小二乘支持向量机存在的参数选择问题,使用了多层动态自适应优化算法来优化最小二乘支持向量机参数.仿真结果表明LS-SVM是一种较为有效的非线性建模方法,具有较快的收敛速度和较高的计算精度,满足电力变压器故障诊断的要求.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.