Wavelet-based feature extraction and selection for classification of power system disturbances using support vector machines

This paper presents a new approach for the classification of the power system disturbances using support vector machines (SVMs). The proposed approach is carried out at three serial stages. Firstly, the features to be form the SVM classifier are obtained by using the wavelet transform and a few different feature extraction techniques. Secondly, the features exposing the best classification accuracy of these features are selected by a feature selection technique called as sequential forward selection. Thirdly, the best appropriate input vector for SVM classifier is rummaged. The input vector is started with the first best feature and incrementally added the chosen features. After the addition of each feature, the performance of the SVM is evaluated. The kernel and penalty parameters of the SVM are determined by cross-validation. The parameter set that gives the smallest misclassification error is retained. Finally, both the noisy and noiseless signals are applied to the classifier given above stages. Experimental results indicate that the proposed classifier is robust and has more high classification accuracy with regard to the other approaches in the literature for this problem.     

Optimal feature selection for classification of the power quality events using wavelet transform and least squares support vector machines

In this paper, a new optimal feature selection based power quality event recognition system is proposed for the classification of power quality events. While Apriori algorithm is capable of processing categorical data, an effective feature vector, which represents distinctive features of digital power quality event data, has been obtained by means of the proposed k-means based Apriori algorithm feature selection approach. The proposed k-means based Apriori algorithm feature selection approach is presented with a power quality event recognition system. In the power quality event recognition system, normalization and segmentation processes have been applied to three-phase event voltage signals. Using 9-level multiresolution analysis, wavelet transform coefficients of the event signals have been obtained. By applying nine different feature extraction processes to these coefficients, a 90 dimensional feature vector belonging to three-phase event voltage signals has been extracted. Optimal feature vector has been obtained by applying the k-means based Apriori algorithm feature selection approach to the obtained feature vector, which has been applied as the last step to the input of the least squares support vector machine classifier and recognition performance results have been obtained. Real power quality event data have been used to evaluate the performance of the proposed feature selection approach and power quality event recognition system. According to the results, the proposed k-means based Apriori algorithm feature selection approach and power quality event recognition system are efficient, reliable and applicable and classify three-phase event types with a high degree of accuracy.     

基于支持向量机的蛋白质相互作用预测

研究蛋白质与蛋白质的相互作用是了解蛋白质功能的重要一步,对于进行药物设计、新陈代谢和信号传导网络的分析具有重要意义。本文采用支持向量机学习方法,利用氨基酸物理化学特性构建支持向量,选取DIP数据库中的酵母表达蛋白进行蛋白质相互作用预测,在34000对酵母蛋白实验数据中,预测准确率可达73.21%,证明了该方法的有效性。     

一种基于K-L变换和支持向量机的图像分割算法

提出了一种基于K-L变换和支持向量机结合的图像分割算法,该算法把轴承中的非缺陷区域和缺陷区域分别看作两种不同的纹理模式,先利用可K-l变换对图像进行降维处理,然后用支持向量机方法对两类不同的样本采样学习,最后进行分类判断。实验结果表明,该算法能够较好地实现图像的分割,有着深入研究的价值。     

基于免疫加权支持向量机方法的短期负荷预测

在对支持向量机（SVM）方法进行分析的基础上，提出了一种免疫加权支持向量机（IWSVM）方法来预测电力系统短期负荷。其中根据各样本重要性的不同，引入了加权支持向量机方法，然后利用免疫规划算法对其进行参数优化。免疫规划算法利用浓度和个体多样性保持机制进行免疫调节，有效地克服了未成熟收敛现象，提高了群体的多样性。电力系统短期负荷预测的实际算例表明，与支持向量机方法相比，所提免疫加权支持向量机方法具有更高的预测精度。     

谷物干燥过程模糊支持向量机控制器的设计

为了准确控制谷物干燥过程的温度和湿度,设计了一种基于改进遗传算法和最小二乘算法的干燥过程模糊支持向量机控制器。利用模糊算法解除温湿度的耦合作用,采用支持向量机实现模糊逻辑控制的全过程和信号的非线线处理,同时采用混合学习算法优化控制器参数,即先采用最小二乘算法离线优化支持向量机性能参数,再采用改进遗传算法在线优化支持向量机性能参数和模糊比例因子,以使其控制性能适应对象的变化而达到最优。仿真结果表明,设计的模糊支持向量机控制器比常规PID控制器和经典模糊控制器具有更好的控制性能,能够满足谷物干燥工艺要求。     

Closed-loop cortical control of direction using support vector machines.

Motor neuroprosthetics research has focused on reproducing natural limb motions by correlating firing rates of cortical neurons to continuous movement parameters. We propose an alternative system where specific spatial-temporal spike patterns, emerging in tasks, allow detection of classes of behavior with the aid of sophisticated nonlinear classification algorithms. Specifically, we attempt to examine ensemble activity from motor cortical neurons, not to reproduce the action this neural activity normally precedes, but rather to predict an output supervisory command to potentially control a vehicle. To demonstrate the principle, this design approach was implemented in a discrete directional task taking a small number of motor cortical signals (8-10 single units) fed into a support vector machine (SVM) to produce the commands Left and Right. In this study, rats were placed in a conditioning chamber performing a binary paddle pressing task mimicking the control of a wheelchair turning left or right. Four animal subjects (male Sprague-Dawley rats) were able to use such a brain-machine interface (BMI) with an average accuracy of 78% on their first day of exposure. Additionally, one animal continued to use the interface for three consecutive days with an average accuracy over 90%.     

基于最小二乘支持向量机的边坡稳定性预测

本文提出一种基于最小二乘支持向量机(LS-SVM)的边坡稳定性预测方法,采用线性函数,多项式函数和径向基函数三种核函数,进行机器学习,经过反复计算和对比分析,建立精度较高的边坡稳定安全系数预测模型.以实例数据作为学习样本和测试样本,对模型进行检验,结果表明LS-SVM建模预测速度快,其预测精度与GA-BP神经网络算法和改进支持向量机算法(ν-SVR)基本相近,将其用于边坡稳定性预测是可行的.     

集员估计的加权最小二乘支持向量机方法

针对带有未知但有界误差的参数非线性回归模型,提出了集员估计的加权最小二乘支持向量机方法.采用加权最小二乘支持向量回归的方法建立逼近方程误差向量的加权l∞范数与参数向量之间的复杂函数关系的模型.根据此模型和可行的方程误差向量的加权1∞范数导出近似参数可行集.为了评估集员估计结果的优劣,给出了反映近似边界接近精确边界程度的指标.仿真结果表明,采用本文方法比采用一般最小二乘支持向量杌的方法所得的近似边界更接近精确边界.     

基于参数优化的支持向量机在电力负荷建模中的应用

以基于参数优化的支持向量机为建模手段来建立电力负荷模型,该算法可自动调整经验风险和VC维之间比重,并由此提高模型的泛化能力.参数优化时采用了结合网格搜索和模式搜索的组合寻优策略优化支持向量机负荷模型的3个参数,并且引入更加客观高效的交叉验证技术参与模型的训练和评价.算例中利用实测数据进行负荷动态建模,结果表明可得到精度和泛化能力都较高的负荷模型,在电力负荷建模方面具有广泛的应用价值.     

Smoke detection in open areas with texture analysis and support vector machines

Early and certain fire detection is one of the important issues to keep infrastructures safe. Especially, it becomes an urgent problem for open places such as port facilities, large factories, and power plants, due to its large harmful effect to the surrounding areas. In these places, direct detection of fire or flame has some difficulties because they are open and hence have problem to set sensor devices. Therefore, smoke is an important and useful sign to detect fire or flames robustly even in such cases. In this paper, we present a novel smoke detection method based on image information. First, we extract moving objects in an image sequence as smoke candidate regions in a preprocessing step. Since smoke has a characteristic pattern as image information, we focus on the texture pattern of smoke. Here, we use texture analysis to extract feature vectors of the images. To classify extracted areas of moving objects to smoke or nonsmoke, we use support vector machines (SVMs) with texture features as an input feature vector. Extraction of moving objects is sometimes easily and greatly affected by environmental conditions such as wind, background objects, and so forth. It obviously causes bad classification results. To solve this problem, we additionally accumulate the results of classification with SVM about time to obtain accurate extraction result of smoke regions under these conditions. Experimental results using real‐scene data show that our method works effectively under several different environmental conditions. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于最小二乘支持向量机的冷端玻璃板位置建模

玻璃生产线上对冷端玻璃板运动位置监测效果的好坏是安全、高效生产的关键,本文尝试了一种改进最小二乘支持向量机的数据拟合算法来对不同时刻冷端玻璃板的运动位置进行建模。支持向量机是针对小样本的新的学习机器,具有良好的泛化性。通过剪枝算法提高其快速性和稀疏性,并用遗传算法搜索向量机的参数,避免了参数选择的盲目性,获得了最优的参数,提高了预测能力。将此法与工程上常使用的非线性回归分析方法进行仿真比较,结果表明基于改进最小二乘支持向量机算法的拟合效果更好。     

最小二乘小波支持向量机在非线性控制中的应用

结合小波技术和支持向量机,提出了一种基于多维允许小波核的最小二乘小波支持向量机,其小波核函数具有近似正交和适用于信号局部分析的特点。同时,给出了一种有效求解最小二乘小波支持向量机的Cholesky分解算法。将最小二乘小波支持向量机应用在非线性系统的自适应控制上,仿真结果表明,与最小二乘支持向量机、多层前向神经网络或模糊逻辑系统相比,最小二乘小波支持向量机均能给出较好的性能,显示出快速而稳定的学习速度,而且在相同条件下,最小二乘小波支持向量机比最小二乘支持向量机的逼近精确度提高了一个数量级。所提出的用于非线性动态系统自适应控制的最小二乘小波支持向量机方法具有效性和实用性。     

基于小波变换和支持向量机的电力系统短期负荷预测

提出一种改进的基于离散小波变换和支持向量机的短期负荷预测方法。运用离散小波变换将负荷时间序列分解为高低频子序列,采用目前较为成熟的支持向量机方法,选择适当的参数对每个序列进行滚动式的单支预测,最后将各分支预测结果相加最终实现负荷预测。实例中负荷数据采用四川省某地区的历史负荷,对该地区的日96点负荷进行全年预测,并将该算法与支持向量机算法进行比较,结果表明,该算法具有较高预测精确性。     

基于小波支持向量机的数字通信信号调制识别

通信信号自动调制识别在电子战、电子侦察中起着重要的作用。通信信号调制识别的任务是确定信号的调制类型和参数。支持向量机是一种新的通用机器学习方法,这种方法被广泛地应用在模式识别、回归估计和概率密度函数估计中。本文在详细分析了数字调制信号的特点以及小波变换提取瞬态特征原理的基础上,提出了一种利用小波变换支持向量机对数字调制信号进行识别的新方法。该方法通过小波变换将输入向量映射到一个高维特征空间,在这个特征空间内,通过构建最优分类面,即可以用支持向量机对数字调制信号进行分类。计算机仿真结果验证了该方法在不同信噪比条件下具有良好的性能。     

System identification techniques based on support vector machines without bias term

The intention of this article is to utilize support vector machines (SVMs) as process models, which are the basis for most controller designs as well as simulation and monitoring tasks. SVMs are data‐driven models comparable with regularization networks, which merge elements from robust statistics, statistical learning, and kernel theory. The presentation is focused on the ‘no‐bias‐term’ variant, accounts for several peculiarities specific to SVM regression and derives an active‐set algorithm to solve the resulting large‐scale quadratic programming problem. For linear systems, SVMs are combined with multi‐stage methods for estimating output error and ARMAX models. Finally, two real‐world processes serve as test cases to evaluate the SVMs’ properties as nonlinear dynamic models. Copyright © 2013 John Wiley & Sons, Ltd.     

基于差分进化优化的支持向量机燃料电池故障诊断

质子交换膜燃料电池是一种多耦合非线性的复杂系统,电堆内部的水淹和膜干故障是其运行过程中最常见的故障.基于差分进化算法优化的支持向量机方法,可以用于燃料电池故障诊断,该方法在传统的支持向量机模型上增加了主成分提取和差分进化算法寻找最优参数,使模型得到更好的训练效果.采用电堆20片单电池电压为数据集进行相关的故障验证分析,结果表明:通过差分进化算法优化的支持向量机在燃料电池故障诊断中有着较高的准确度,具有一定的工程应用价值.     

一种基于最小二乘支持向量机的年电力需求预测方法

针对电力系统年用电量增长的特点,将最小二乘支持向量机LS-SVM(least squares support vector m a-ch ine)回归模型引入年电力需求预测领域,并给出了相应的过程和算法。与常规基于人工神经网络ANN(ar-tific ial neural networks)的智能预测方法比较,该模型优点是明显的:1)将神经网络迭代学习问题转化为直接求解多元线性方程;2)整个训练过程中有且仅有一个全局极值点,确定了预测的稳定性;3)将年电力需求预测的外插回归问题转换为内插问题,提高了预测精度。应用实例表明:该模型实现容易、预测精度高,更适合年电力需求预测。     

Partial discharge signal denoising with spatially adaptive wavelet thresholding and support vector machines

In this paper an improved method to denoise partial discharge (PD) signals is presented. The method is based on the wavelet transform (WT) and support vector machines (SVM) and is distinct from other WT-based denoising strategies in the sense that it exploits the high spatial correlations presented by PD wavelet decompositions as a way to identify and select the relevant coefficients. PD spatial correlations are characterized by WT modulus maxima propagation along decomposition levels (scales), which are a strong indicative of the their time-of-occurrence. Denoising is performed by identification and separation of PD-related maxima lines by an SVM pattern classifier. The results obtained confirm that this method has superior denoising capabilities when compared to other WT-based methods found in the literature for the processing of Gaussian and discrete spectral interferences. Moreover, its greatest advantages become clear when the interference has a pulsating or localized shape, situation in which traditional methods usually fail.     

基于自适应双向加权最小二乘支持向量机的超短期负荷预测

应用模糊加权最小二乘支持向量机对超短期负荷进行预测,为了体现离预测点越远的历史负荷数据对预测点负荷值的影响越不明显的特点,即"近大远小"的原则,在双向,即横向(输入样本)与纵向(训练样本集)引入时间域的隶属分布.并用快速留一法在线优化模型的参数,实现了相关参数的自适应选择,克服了应用固定系数进行预测的缺点.应用某地区的负荷数据进行了仿真预测,并应用不同的方法进行了对比.结果表明,所提出的方法与传统方法相比提高了超短期负荷的预测精度.