Covariance-guided landmine detection and discrimination using ground-penetrating radar data

Ground penetrating Radar (GPR) can detect and deliver the response signal from any buried kind of object like plastic or metallic landmines, stones, and wood sticks. It delivers three kinds of data: Ascan, Bscan, and Cscan. However, it cannot discriminate between landmines and inoffensive objects or ‘clutter.’ One-class classification is an alternative to detect landmines, especially, as landmines features data are unbalanced. In this article, we investigate the effectiveness of the Covariance-guided One-Class Support Vector Machine (COSVM) to detect, discriminate, and locate landmines efficiently. In fact, compared to existing one-class classifiers, the COSVM has the advantage of emphasizing low variance directions. Moreover, we will compare the one-class classification to multiclass classification to tease out the advantage of the former over the latter as data are unbalanced. Our method consists of extracting Ascan GPR data. Extracted features are used as an input for COSVM to discriminate between landmines and clutter. We provide an extensive evaluation of our detection method compared to other methods based on relevant state of the art one-class and multiclass classifiers, on the well-known MACADAM database. Our experimental results show clearly the superiority of using COSVM in landmine detection and localization.     

基于改进单类支持向量机的工业控制网络入侵检测方法

针对单类支持向量机（OCSVM）入侵检测方法无法检测内部异常点和离群点导致决策函数偏离训练样本的问题,提出了一种结合具有噪声的密度聚类（DBSCAN）方法和K-means方法的OCSVM异常入侵检测算法。首先通过DBSCAN算法,剔除训练数据中的离群点,消除离群点的影响;然后利用K-means划分数据类簇的方法筛选出内部异常点;最后利用OCSVM算法为每一个类簇建立单分类器用于检测异常数据。工控网络数据集上的实验结果表明,该组合分类器能够利用无异常数据样本检测出工控网络入侵,并且提高了OCSVM方法的检测效果。在气体管道网络数据集入侵检测实验中,所提方法的总体检测率为91.81%;而原始OCSVM算法则为80.77%。     

基于图卷积神经网络的医保欺诈检测算法

针对医疗保险欺诈检测当中欺诈样本不足、数据标注昂贵和传统基于欧氏空间的模型准确率低的问题,提出了一种新的基于图卷积和变分自编码的单分类医保欺诈检测模型(OCGVAE)。首先,通过病人就诊记录建立社交网络,计算病人和医生之间的权重关系,并设计了一个2层的图卷积神经网络(GCN)作为社交网络数据的输入,用以降低社交网络的数据维度;然后,设计了一个变分自编码(VAE)用以实现只存在一类欺诈样本标签的情况下的模型训练;最后,设计了一个逻辑回归(LR)模型用以判别数据类别。实验结果表明,OCGVAE模型的检测准确率达到87.26%,相较于一类对抗神经网络(OCAN)、一类高斯过程(OCGP)、一类近邻(OCNN)、一类支持向量机(OCSVM)和半监督图卷积神经网络(Semi-GCN)算法,分别高出16.1%、70.2%、31.7%、36.5%和27.6%,说明所提模型有效提高了医保欺诈筛查精度。     

Abrupt change detection with One-Class Time-Adaptive Support Vector Machines

We recently introduced an algorithm for training a sequence of coupled Support Vector Machines which shows promising results in the field of non-stationary classification problems Grinblat, Uzal, Ceccatto, and Granitto (2011). In this paper we analyze its application to the abrupt change detection problem. With this goal, we first introduce and analyze an extension of it to deal with the One-Class Support Vector Machine (OC-SVM) problem, and then discuss its use as an improved abrupt change detection method. Finally, we apply the proposed procedure to artificial and real-world examples, and demonstrate that it is competitive by comparison against other abrupt change detection methods.     

基于OC-SVM的大型数据集分类方法

支持向量机是最有效的分类技术之一,具有很高的分类精度和良好的泛化能力,但其应用于大型数据集时的训练过程还是非常复杂。对此提出了一种基于单类支持向量机的分类方法。采用随机选择算法来约简训练集,以达到提高训练速度的目的;同时,通过恢复超球体交集中样本在原始数据中的邻域来保证支持向量机的分类精度。实验证明,该方法能在较大程度上减小计算复杂度,从而提高大型数据集中的训练速度。     

基于决策树对支持向量机的医学图像分类新方法

针对传统对支持向量机多类分类算法（Multi-TWSVM）中出现的模糊性问题,提出了一种基于遗传算法的决策树对支持向量机（GA-DTTSVM）多类分类算法。GA-DTTSVM用遗传算法对特征数据建立决策树,通过构建决策树可以分离样本的模糊区域,提高模糊区域样本的识别率。在决策树的每个节点上用对支持向量机（TWSVM）训练分类器,最后用训练的分类器进行分类和预测。实验结果表明,与决策树对支持向量机（DTTSVM）多类分类算法以及Multi-TWSVM相比,GA-DTTSVM多类分类算法具有较高的分类精度和较快的训练速度。     

Comparative Study of ELM and SVM in Hyperspectral Image Supervision Classification

Combining the spatial features and spectral feature of hyperspectral remote sensing image in supervised classification can effectively improve the classification time and accuracy.In this study,the spatial information extraction method,named watershed transform,was combined with the Extreme Learning Machine(ELM)and Support Vector Machine(SVM)methods.The classification results of the datasets with the spatial features and without the spatial features were synthetically evaluated and compared.Two hyperspectral datasets,the ROSIS data of Pavia university and the Hyperion data of Okavango Delta(Botswana),were selected to test the methods.After preprocessing,the training samples were selected from the images as the reference areas for each type,and the spectral features of each type were analyzed.The two classification methods were utilized to classify the hyperspectral datasets and relevant classification results were obtained.based on the validation samples selected from the images,the classification results were evaluated using the confusion matrix and the execution times.After that,the spectral features and spatial features were combined to classify the data.The results show that the Extreme Learning Machine(ELM) is superior to the Support Vector Machine(SVM)in the classification time and precision,and the spatial features are introduced in the classification process,which can effectively improve the classification accuracy.     

基于单类支持向量机的音频分类

研究一种基于单类支持向量机的音频分类方法,能够使每一类样本都独立地获得一个决策函数,通过决策函数的最大值来判断样本所属的类。通过使用小波包变换提取语音特征向量,并融合多特征向量,将音频分为5类：纯语音、音乐、环境音、含背景音语音和静音。实验结果表明这种方法具有较好的分类精度,性能优于贝叶斯、隐马尔可夫模型和神经网络分类器。     

一种基于快速增量SVM的入侵检测方法

针对基于支持向量机(SVM)的入侵检测方法检测率低、检测速度慢的问题,提出一种基于快速增量SVM的入侵检测方法 B-ISVM。该方法在确定邻界区后筛选其中的样本进行训练,完成分类超平面的初步构造,利用筛选因子提取支持向量,再进行基于KKT条件的增量学习,实现增量SVM分类器的构造。实验结果表明,该方法可以提高入侵检测率和检测速度,拥有更好的分类性能。     

核向量机与支持向量机相结合的二阶段快速学习方法

支持向量机(SVM)作为一种有效的模式分类方法,当数据集规模较大时,学习时间长、泛化能力下降;而核向量机(CVM)分类算法的时间复杂度与样本规模无关,但随着支持向量的增加,CVM的学习时间会快速增长。针对以上问题,提出一种CVM与SVM相结合的二阶段快速学习算法(CCS),首先使用CVM初步训练样本,基于最小包围球(MEB)筛选出潜在核向量,构建新的最有可能影响问题解的训练样本,以此降低样本规模,并使用标记方法快速提取新样本;然后对得到的新训练样本使用SVM进行训练。通过在6个数据集上与SVM和CVM进行比较,实验结果表明,CCS在保持分类精度的同时训练时间平均减少了30%以上,是一种有效的大规模分类学习算法。     

基于健壮支持向量机的异常检测

用于异常检测的机器学习方法,如神经网络和支持向量机,都对训练样本的噪声非常敏感,进而导致推广能力和分类准确性的下降。为了解决上述问题,论文提出一种新的基于健壮支持向量机的方法。先将RSVM与标准SVM作了对比,然后使用1998DARPABSM的数据作为评估数据。实验表明,该方法在入侵检测的准确率、误检率和有噪声情况下的推广能力和运行时等多项指标上都有良好的表现。     

Extraction of earthquake-induced collapsed buildings using very high-resolution imagery and airborne lidar data

Extraction of urban building damage caused by earthquake disasters, from very-high-resolution (VHR) satellite imagery and related geospatial data, has been widely studied in the past decade. In this study, a multi-stage collapsed building detection method, using bi-temporal (pre- and post-earthquake) VHR images and post-earthquake airborne light detection and ranging (lidar) data, is proposed. Ground objects that are intact and significantly different from collapsed buildings, such as intact buildings, pavements, shadows, and vegetation, were first extracted using the post-event VHR image and lidar data and masked out. Collapsed buildings were then extracted by classifying the combined bi-temporal VHR images and texture images of the remaining area using a one-class classifier, the One-Class Support Vector Machine (OCSVM). A post-processing procedure was adopted to refine the obtained result. The proposed method was quantitatively evaluated and compared to two existing methods in Port au Prince, Haiti, which was heavily hit by an earthquake in January 2010. In the two comparative methods, data for the whole study area were directly used. In the first method, collapsed buildings were extracted directly using the OCSVM, while in the second method, buildings and pavements were removed from the extraction result of the first method. The results showed that the proposed method significantly outperformed the existing methods, with increases of 21% and 40%, respectively, in the kappa coefficient. The proposed method provides a fast and reliable method to detect collapsed urban buildings caused by earthquake disasters, and could also be applied to other study areas using similar data combinations.     

用于多分类问题的最小二乘支持向量分类-回归机

基于支持向量机(SVM)的三分类方法是处理多分类问题的一类方法。提出了最小二乘支持向量分类〖CD*2〗回归机(LSSVCR)算法,通过最小二乘目标函数充分考虑所有样本点对分类的影响,使得训练集中即使有个别样本点被标错类别,对分类结果也不会产生太大的影响,从而提高分类的准确性。该方法能够提高分类的准确率和分类速度,同时算法对于不同类别间样本数目差异较大的情况也有很好的分类效果。数值实验结果表明所提算法是可行的,且与已有的三分类算法相比在分类准确性上平均提高了2.57%,在运算速度上也有了较大的提高。     

Multi-category laplacian least squares twin support vector machine

In this paper, we have formulated a Laplacian Least Squares Twin Support Vector Machine called Lap-LST-KSVC for semi-supervised multi-category k-class classification problem. Similar to Least Squares Twin Support Vector Machine for multi-classification(LST-KSVC), Lap-LST-KSVC, evaluates all the training samples into “1-versus-1-versus-rest” classification paradigm, so as to generate ternary output {?1, 0, +1}. Experimental results prove the efficacy of the proposed method over other inline Laplacian Twin Support Vector Machine(Lap-TWSVM) in terms of classification accuracy and computational time.     

基于RST修正核单类SVM的程序行为控制系统

程序行为控制系统对程序行为进行建模、检测和响应。单类支持向量机(SVM)在有限样本的情况下用于异常检测,具有较好的分类精度和泛化能力。针对以前利用单类支持向量机进行异常检测的研究中没有考虑属性权重的问题,该文提出利用粗糙集理论(RST),引入反映属性重要性程度的权重值。给出通过找出决策系统中所有约简的集合确定属性权重的方法,并利用属性权重修正单类SVM的核函数。实验表明基于RST修正核的单类SVM具有更好的检测能力。     

基于单类支持向量机的电子鼻在白酒真假识别中的应用

针对采用多类分类方法进行白酒真假识别时存在的真酒样本和假酒样本（正类样本和异类样本）数量无法均衡以及异类样本无法全部获取的问题,提出应用单类支持向量机分别单独对每一种品牌的白酒训练单类分类器进行真假识别的方法。首先采用自主设计的电子鼻系统对不同品牌白酒进行采样测试;采样后的传感器阵列数据依次经过数据预处理、特征生成、特征选择降维处理,得到可用于分类的白酒样本;再通过格点搜索获取每种白酒单类分类器的最优参数;最后测试各个单类分类器对相应品牌白酒的真假识别效果。各单类分类器的真假识别率分布在93%~98%之间,结果表明,采用自主设计的电子鼻结合单类支持向量机可以很好地对白酒真假进行识别。     

Hierarchical linear support vector machine

The increasing size and dimensionality of real-world datasets make it necessary to design efficient algorithms not only in the training process but also in the prediction phase. In applications such as credit card fraud detection, the classifier needs to predict an event in 10 ms at most. In these environments the speed of the prediction constraints heavily outweighs the training costs. We propose a new classification method, called a Hierarchical Linear Support Vector Machine (H-LSVM), based on the construction of an oblique decision tree in which the node split is obtained as a Linear Support Vector Machine. Although other methods have been proposed to break the data space down in subregions to speed up Support Vector Machines, the H-LSVM algorithm represents a very simple and efficient model in training but mainly in prediction for large-scale datasets. Only a few hyperplanes need to be evaluated in the prediction step, no kernel computation is required and the tree structure makes parallelization possible. In experiments with medium and large datasets, the H-LSVM reduces the prediction cost considerably while achieving classification results closer to the non-linear SVM than that of the linear case.     

基于SVDD的轻轨锚固螺杆故障诊断研究

为了实现对重庆市轻轨轨道梁锚固螺杆的故障检测,提出了一种基于支持向量数据描述的锚固螺杆故障诊断方法,该方法只需要正常螺杆样本,且不需要对原始数据进行特征提取,就可以建立单值分类器,解决了缺少故障螺杆样本的难题。通过与常见的三种单值分类方法比较,表明SVDD分类器具有很好的分类效果和计算效率,能较好地区分正常螺杆和非正常螺杆,为轻轨锚固螺杆故障检测提供了新的诊断方法。     

基于SVM的大鱼际掌纹图像二分类法

提出一种基于支持向量机(SVM)的大鱼际掌纹图像二分类法。采用高频强调滤波,对分割得到的大鱼际掌纹图像进行图像增强,提取其灰度共生矩阵4个方向的8个特征量作为分类特征向量。对比不同核函数下的分类准确率,结果表明,组合特征向量的SVM方法对大鱼际掌纹的初步二分类效果较好。