基于推土机距离和支持向量机的脑电癫痫检测算法(英文)

对于需要长期脑电图监测的癫痫患者,癫痫自动检测技术是十分必要的。本文所提出的基于多导联长程脑电的算法,首先,对脑电信号进行五层小波分解,取其中三层并求和,然后建立直方图并计算它们之间的距离。本文使用了一种有效的推土机距离算法,提出了脑电新特征EMD-L1。由于EMD-L1利用了L1范式,有效降低了时间复杂度,提高了运算速度。本文采用支持向量机作为分类器,并对支持向量机的输出做了后处理,其中包括平滑滤波和"collar"技术,以获取更准确的检测结果。本文将所提出的方法与其他使用相同脑电数据库的癫痫检测方法相比较,实验结果表明本文提出的算法达到了较高的灵敏度95.73%、特异性98.45%以及较低的误判率0.33/h。该检测系统不但具有较高的精确度和较强的鲁棒性,而且可以对脑电数据进行实时分析,用于长期脑电监测中。     

基于ELM和近似熵的脑电信号检测方法

脑电癫痫波的自动检测与分类对癫痫病情的诊断具有重要意义。提出了一种基于极端学习机(extreme learning ma-chine,ELM)和近似熵的脑电信号检测方法。首先,计算脑电信号的近似熵作为非线性特征,并与利用小波变换技术提取的线性特征波动指数相结合,组成特征向量,然后将特征向量送入单隐层前馈神经网络,采用ELM学习算法训练网络。实验表明,与BP(backpropagation)和SVM(support vector machine)算法相比,ELM在训练时间和识别精度两方面性能最佳,对用于实验的脑电数据检测识别率达到98%以上。     

基于深度学习的癫痫脑电不平衡分类方法

癫痫发作自动检测技术对癫痫患者的诊断和治疗具有重要意义。由于癫痫发作期持续时间较短,发作期与非发作期的脑电数据分布是不平衡的。针对该问题,本文提出了一种不平衡分类与深度学习相结合的癫痫发作自动检测方法。首先,为防止不同类别数据之间界限模糊,使用Borderline-SMOTE算法对1/3训练集做平衡处理;之后,设计了金字塔型的一维深度卷积神经网络,并利用平衡处理的训练集进行训练。与常见的二维卷积神经网络不同,本文构造的一维卷积神经网络减少了训练参数,提高了训练速率,能够有效地避免由于训练样本较少而造成的过拟合。在长达991小时的长程头皮脑电数据集上的实验表明,经过平衡处理后的检测效果得到明显改善,最佳敏感度达到92.35%,特异性达到99.88%,阳性预测率达到90.68%,阴性预测率达到99.91%。同时,与其他癫痫检测方法的比较表明,本文方法具有更好的检测结果,更加符合临床应用的要求。     

癫痫发作瞬态带宽特征自适应检测方法

癫痫是常见的神经系统疾病之一。癫痫发作的识别通常采用脑电测量记录中的癫痫发作起始点,以辅助医生进行诊断并对患者的发作状态报警。利用脑电信号的瞬态参数提出了一种自适应带宽特征,可用于提高癫痫发作检测精度。首先,利用经验模态分解(EMD)求得脑电信号的本征模态函数(IMF),并计算特定阶次IMF的解析信号;其次,利用该解析信号求解瞬时幅值与瞬时频率,对EEG信号的带宽特征添加权重,得到可用于癫痫检测的自适应带宽特征(Adaptive Bandwidth);最后,利用该特征完成癫痫发作检测。采用长达118 h 49 min的癫痫患者临床脑电数据进行实验,实验结果表明,自适应带宽特征的敏感性、特异性、准确性参数均比原特征取得明显提高。自适应带宽特征可提高癫痫发作检测精度并降低时间延迟,便于及时采取治疗措施,为临床检测提供了重要依据。     

基于深度网络迁移学习的致痫区脑电识别

致痫区脑电识别能够为癫痫外科手术提供重要的参考价值。提出了一种基于深度网络迁移学习的致痫区脑电识别算法。首先利用连续小波变换(CWT)对脑电信号进行时频分析,获得脑电信号时频图;然后迁移学习AlexNet网络模型,调整网络结构使之适应于致痫区脑电识别,将模型第7层全连接层输出作为脑电信号时频图的特征表示,最后利用支持向量机(SVM)、BP神经网络、长短期记忆网络(LSTM)、基于稀疏表达分类算法(SRC)、线性判别分析(LDA)等分类算法进行特征分类。基于开源脑电数据集采用十折交叉验证的方法对算法进行了验证,比较6种分类器的效果,得到SVM算法的平均特异性为88.81%,灵敏度为88.07%,准确率为88.44%,证明了该方法识别致痫区脑电信号的有效性。     

基于深度网络迁移学习的致痫区脑电识别* .txt

摘要：致痫区脑电识别能够为癫痫外科手术提供重要的参考价值。提出了一种基于深度网络迁移学习的致痫区脑电识别算法。首先利用连续小波变换（CWT）对脑电信号进行时频分析,获得脑电信号时频图;然后迁移学习AlexNet网络模型,调整网络结构使之适应于致痫区脑电识别,将模型第7层全连接层输出作为脑电信号时频图的特征表示,最后利用支持向量机（SVM）、BP神经网络、长短期记忆网络（LSTM）、基于稀疏表达分类算法（SRC）、线性判别分析（LDA）等分类算法进行特征分类。基于开源脑电数据集采用十折交叉验证的方法对算法进行了验证,比较6种分类器的效果,得到SVM算法的平均特异性为8881%,灵敏度为8807%,准确率为8844%,证明了该方法识别致痫区脑电信号的有效性。 .txt     

一种新的脑电特征提取方法研究

基于控制信号为皮层慢电位的脑机接口数据,本文提出了一种脑电模式识别的新方法.该算法将脑电数据的近似熵值、自相关系数和皮层慢电位组合成新的特征向量,并选取k-近邻法作为分类器进行模式识别.在公开测试集中,新算法能达到较高的识别率,同时表明近似熵和自相关系数可以作为新参量对脑电数据进行分析.     

基于图谱分析的脑电网络研究

针对脑活动过程功能连接网络分析问题,将图谱域分析技术应用于脑电网络研究中。对各导联脑电信号特征节律提取、不同测量节点之间脑电信号特征节律相关系数邻接矩阵及拉普拉斯矩阵进行了研究,并对拉普拉斯矩阵分解得到的不同阶次分量矩阵以及二值化处理得到的不同阶次脑电网络拓扑结构进行了分析,提出了一种基于图谱分析的脑电网络研究方法;采用癫痫患者正常情况与癫痫发作阶段的脑电信号对提出的方法进行了测试。实验结果表明:在两种情况下,提出的图谱分析方法均能有效提取不同变化模式的脑电网络拓扑结构,并能实现正常区域与癫痫发作区域的有效分类,接收者操作特征曲线下面积为0. 834;分类结果优于常用的对比方法。     

P300 Speller中基于AdaBoost SVM的导联筛选研究

P300 Speller是目前少数可以用于临床残疾人功能补偿的脑-机接口系统,P300 Speller的字符识别效率与脑电信号采集的头皮表面电极位置密切相关,过多的电极不但增加了使用者的不适感,且易引入噪声干扰进而影响系统的稳定性。采用并发展了一种基于AdaBoost SVM(adaptive boosting support vector machine)的特征筛选方法,对脑电导联进行优化筛选,通过对6位受试者的实验数据处理及分析,结果表明该方法可以在不显著影响识别效率的基础上降低导联数量76%以上。另外,相较于经典的SVM-RFE特征筛选方法,该方法极大降低了计算复杂度,更适用于训练数据庞大的脑电特征优化问题。     

基于改进Sobel算法的实时图像边缘检测系统设计

针对传统Sobel边缘检测算法需要人为指定阈值而且检测出的边缘较宽等问题,提出一种自适应阈值和非极大值抑制相结合的边缘检测算法。引入中值滤波的思想生成自适应动态阈值,将该值作为二值化处理的阈值,并采用非极大值抑制的方法细化梯度图像,同时通过增加梯度检测方向提高了算法对复杂纹理的识别能力。将改进后的算法在FPGA平台上实现,实验验证了其有效性。     

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.     

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....     

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。     

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.