Toward automatic detection of brain responses to emotional music through analysis of EEG effective connectivity

The purpose of this study was to investigate the effective brain networks associated with joyful, melancholic, and neutral music. Connectivity patterns among EEG electrodes in different frequency bands were extracted by multivariate autoregressive modeling while 19 nonmusicians listened to selected classical and Iranian musical excerpts. Musical selections were categorized according to the participants' average self-assessment results. Connectivity matrices were analyzed to identify distinct variations in the connectivity indices related to the categorized excerpts. We studied the correlation of inter-/intra-regional connectivity patterns with the self-reported evaluations of the musical selections. The perceived valence was positively correlated with the frontal inter-hemispheric flow, but negatively correlated with the parietal bilateral connectivity. Using the connectivity indices between different cortical areas and a support vector machine, we sought to distinguish trials in terms of the self-reported valence of perceived emotions and the familiarity of the musical genres. For 16 participants, the average classification accuracies in discriminating joyful from neutral, joyful from melancholic and familiar from unfamiliar trials were 93.7% ± 1.06%, 80.43% ± 1.74%, and 83.04% ± 1.47, respectively. Integration of different cortical areas is required for music perception and emotional processing. Thus, by studying the connectivity of brain regions, we may be able to develop a noninvasive assessment tool for investigating musical emotions.     

Classifying mental tasks based on features of higher-order statistics from EEG signals in brain-computer interface

In order to characterize the non-Gaussian information contained within the EEG signals, a new feature extraction method based on bispectrum is proposed and applied to the classification of right and left motor imagery for developing EEG-based brain-computer interface systems. The experimental results on the Graz BCI data set have shown that based on the proposed features, a LDA classifier, SVM classifier and NN classifier outperform the winner of the BCI 2003 competition on the same data set in terms of either the mutual information, the competition criterion, or misclassification rate.     

基于脑电信号的情感识别研究

针对如何提高脑电信号情感识别的正确率这一问题,在得到的原始脑电信号进行分频带特征提取后,一方面采用支持向量机、K近邻算法、朴素贝叶斯和神经网络算法对小波熵、近似熵、功率谱密度、微分熵,进行训练和分类学习;另一方面,基于四种不同的电极放置方式,对微分熵特征采用支持向量机和经遗传算法参数寻优的支持向量机算法进行训练。结果显示,在12通道条件下能够得到91.99%的总体准确率,最高情感识别准确率已经达到97.59%。研究结果表明,减少电极可以获得较高的情感识别分类结果,并且采用参数寻优后的支持向量机算法能够有效提升准确率。     

Automatic recognition of epileptic EEG patterns via Extreme Learning Machine and multiresolution feature extraction

Epilepsy is one of the most common neurological disorders- approximately one in every 100 people worldwide are suffering from it. In this paper, a novel pattern recognition model is presented for automatic epilepsy diagnosis. Wavelet transform is investigated to decompose EEG into five EEG frequency bands which approximate to delta (δ), theta (θ), alpha (α), beta (β), and gamma (γ) bands. Complexity based features such as permutation entropy (PE), sample entropy (SampEn), and the Hurst exponent (HE) are extracted from both the original EEG signals and each of the frequency bands. The wavelet-based methodology separates the alterations in PE, SampEn, and HE in specific frequency bands of the EEG. The effectiveness of these complexity based measures in discriminating between normal brain state and brain state during the absence of seizures is evaluated using the Extreme Learning Machine (ELM). It is discovered that although there exists no significant differences in the feature values extracted from the original EEG signals, differences can be recognized when the features are examined within specific EEG frequency bands. A genetic algorithm (GA) is developed to choose feature subsets that are effective for enhancing the recognition performance. The GA is also examined for weight alteration for both sensitivity and specificity. The results show that the abnormal EEG diagnosis rate of the model without the involvement of the genetic algorithm is 85.9%. However, the diagnosis rate of the model increases to 94.2% when the genetic algorithm is integrated as a feature selector.     

DEAR-MULSEMEDIA: Dataset for emotion analysis and recognition in response to multiple sensorial media

Traditionally, emotion recognition is performed in response to stimuli that engage either one (vision: image or hearing: audio) or two (vision and hearing: video) human senses. An immersive environment can be generated by engaging more than two human senses while interacting with multimedia content and is known as MULtiple SEnsorial media (mulsemedia). This study aims to create a new dataset of multimodal physiological signals to recognize emotions in response to such content. To this end, four multimedia clips are selected and synchronized with fan, heater, olfaction dispenser, and haptic vest to augment cold air, hot air, olfaction, and haptic effects respectively. Furthermore, physiological responses including electroencephalography (EEG), galvanic skin response (GSR), and photoplethysmography (PPG) are observed to analyze human emotional responses while experiencing mulsemedia content. A t-test applied using arousal and valence scores show that engaging more than two human senses evokes significantly different emotions. Statistical tests on EEG, GSR, and PPG responses also show a significant difference between multimedia and mulsemedia content. Classification accuracy of 85.18% and 76.54% is achieved for valence and arousal, respectively, using K-nearest neighbor classifier and feature-level fusion strategy.     

A modified hybrid neural network for pattern recognition and its application to SSW complex in EEG

In this study, a modified hybrid neural network with asymmetric basis functions is presented for feature extraction of spike and slow wave complexes in electroencephalography (EEG). Feature extraction process has a great importance in all pattern recognition and classification problems. A gradient descent algorithm, indeed a back propagation type, is adapted to the proposed artificial neural network. The performance of the proposed network is measured using a support vector machine classifier fed by features extracted using the proposed neural network. The results show that the proposed neural network model can effectively be used in pattern recognition tasks. In experiments, real EEG data are used.     

Classification and regression models of audio and vibration signals for machine state monitoring in precision machining systems

We present a data-driven method for monitoring machine status in manufacturing processes. Audio and vibration data from precision machining are used for inference in two operating scenarios: (a) variable machine health states (anomaly detection); and (b) settings of machine operation (state estimation). Audio and vibration signals are first processed through Fast Fourier Transform and Principal Component Analysis to extract transformed and informative features. These features are then used in the training of classification and regression models for machine state monitoring. Specifically, three classifiers (K-nearest neighbors, convolutional neural networks and support vector machines) and two regressors (support vector regression and neural network regression) were explored, in terms of their accuracy in machine state prediction. It is shown that the audio and vibration signals are sufficiently rich in information about the machine that 100% state classification accuracy could be accomplished. Data fusion was also explored, showing overall superior accuracy of data-driven regression models.     

基于局部特征过滤的快速火焰图像识别方法

传统的基于物理信号的火焰识别方法易被外部环境干扰,且现有火焰图像特征提取方法对于火焰和场景的区分度较低,从而导致火焰种类或场景改变时识别精度降低。针对这一问题,提出一种基于局部特征过滤和极限学习机的快速火焰识别方法,将颜色空间信息引入尺度不变特征变换（SIFT）算法。首先,将视频文件转化成帧图像,利用SIFT算法对所有图像提取特征描述符;其次,通过火焰在颜色空间上的信息特性进一步过滤局部噪声特征点,并借助关键点词袋（BOK）方法,将特征描述符转换成对应的特征向量;最后放入极限学习机进行训练,从而快速得到火焰识别模型。在火焰公开数据集及真实火灾场景图像进行的实验结果表明：所提方法对不同场景和火焰类型均具有较高的识别率和较快的检测速度,实验识别精度达97%以上;对于包含4301张图片数据的测试集,模型识别时间仅需2.19 s;与基于信息熵、纹理特征、火焰蔓延率的支持向量机模型,基于SIFT、火焰颜色空间特性的支持向量机模型,基于SIFT的极限学习机模型三种方法相比,所提方法在测试集精度、模型构建时间上均占有优势。     

Fractional-order embedding canonical correlation analysis and its applications to multi-view dimensionality reduction and recognition

Due to the noise disturbance and limited number of training samples, within-set and between-set sample covariance matrices in canonical correlation analysis (CCA) usually deviate from the true ones. In this paper, we re-estimate within-set and between-set covariance matrices to reduce the negative effect of this deviation. Specifically, we use the idea of fractional order to respectively correct the eigenvalues and singular values in the corresponding sample covariance matrices, and then construct fractional-order within-set and between-set scatter matrices which can obviously alleviate the problem of the deviation. On this basis, a new approach is proposed to reduce the dimensionality of multi-view data for classification tasks, called fractional-order embedding canonical correlation analysis (FECCA). The proposed method is evaluated on various handwritten numeral, face and object recognition problems. Extensive experimental results on the CENPARMI, UCI, AT&T, AR, and COIL-20 databases show that FECCA is very effective and obviously outperforms the existing joint dimensionality reduction or feature extraction methods in terms of classification accuracy. Moreover, its improvements for recognition rates are statistically significant on most cases below the significance level 0.05.     

An exploratory study using inexpensive electroencephalography (EEG) to understand flow experience in computer-based instruction

Flow is an optimal experience that results in intense engagement in an activity. In computer-based instructional environment, flow can be used to examine learning performance. We used questionnaire survey and electroencephalography (EEG) analysis to examine the influence of challenge-skill balance on the flow experience and influence of flow experience on learning performance in a computer-based instructional environment. The results showed that the flow experience of learners depends on challenge-skill balance of learning materials. The research explored the possibility of using an inexpensive non-medical EEG device to research the association between flow experience and challenge-skill balance in educational information systems.     

改进的F-score算法在语音情感识别中的应用

针对F-score特征选择算法不能揭示特征间互信息而不能有效降维这一问题,应用去相关的方法对F-score进行改进,利用德语情感语音库EMO-DB,在提取语音情感特征的基础上,根据支持向量机（SVM）的分类精度选择出分类效果最佳的特征子集。与F-score特征选择算法对比,改进后的算法实现了候选特征集较大幅度的降维,选择出了有效的特征子集,同时得到了较理想的语音情感识别效果。     

EMD在语音情感识别中的应用与研究

语音情感计算引起了国内外广泛的关注,特别是在语音情感特征提取方面做了大量的研究。利用经验模态分解(EMD)方法对情感语音进行处理,得到情感语音的前4阶固有模态函数(IMF),并将前4阶IMF分别通过Hilbert变换得到其瞬时频率和瞬时振幅。提取它们的统计特征,再结合情感语音的声学特征共同组成情感特征向量,并对特征向量做归一化处理。利用支持向量机(SVM)对四种情感语音即生气、高兴、悲伤和平静进行识别。实验结果表明该方法的识别效果较好。     

Extraction and analysis of multiple time window features associated with muscle fatigue conditions using sEMG signals

In this work, an attempt has been made to differentiate surface electromyography (sEMG) signals under muscle fatigue and non-fatigue conditions with multiple time window (MTW) features. sEMG signals are recorded from biceps brachii muscles of 50 volunteers. Eleven MTW features are extracted from the acquired signals using four window functions, namely rectangular windows, Hamming windows, trapezoidal windows, and Slepian windows. Prominent features are selected using genetic algorithm and information gain based ranking. Four different classification algorithms, namely naïve Bayes, support vector machines, k-nearest neighbour, and linear discriminant analysis, are used for the study. Classifier performances with the MTW features are compared with the currently used time- and frequency-domain features. The results show a reduction in mean and median frequencies of the signals under fatigue. Mean and variance of the features differ by an order of magnitude between the two cases considered. The number of features is reduced by 45% with the genetic algorithm and 36% with information gain based ranking. The k-nearest neighbour algorithm is found to be the most accurate in classifying the features, with a maximum accuracy of 93% with the features selected using information gain ranking.     

应用复小波和独立成分分析的人脸识别

结合双树复小波变换（DT-CWT）和独立成分分析（ICA）提出了一种人脸识别新方法。该方法首先应用双树复小波变换提取图像的特征向量,接着通过主成分分析（PCA）降低特征向量的维数,在此基础上应用独立成分分析提取统计上独立的特征向量,然后基于相关系数的分类器对特征向量进行分类。双树复小波变换具有方向与尺度选择性,并能有效的保持图像的频域信息,其与独立成分分析相结合提取的特征具有良好的分类性能。在ORL和AR人脸图像数据库上进行算法验证的结果表明该方法的有效性。     

基于行为特征分析的微博恶意用户识别

近年来,社交网络数据挖掘作为物理网络空间数据挖掘的一大热点,目前在用户行为分析、兴趣识别、产品推荐等方面都取得了令人可喜的成果。随着社交网络商业契机的到来,出现了很多恶意用户及恶意行为,给数据挖掘的效果产生了极大的影响。基于此,提出基于用户行为特征分析的恶意用户识别方法,该方法引入主成分分析方法对微博网络用户行为数据进行挖掘,对各维度特征的权重进行排序,选取前六维主成分特征可以有效识别恶意用户,主成分特征之间拟合出的新特征也能提升系统的识别性能。实验结果表明,引入的方法对微博用户特征进行了有效的排序,很好地识别出了微博社交网络中的恶意用户,为其他方向的社交网络数据挖掘提供了良好的数据清洗技术。     

基于改进粒子群优化的支持向量机与情景感知的人体活动识别

针对目前人体活动类别识别准确率偏低的问题,提出一种支持向量机（SVM）与情景分析（人体运动状态转换的实际逻辑或统计模型）相结合的识别方法,对人体日常的六种活动（步行、上楼、下楼、坐下、站立、躺下）进行识别。该方法利用了人体活动样本之间存在逻辑关系的特点,首先使用经改进的粒子群优化（IPSO）算法对SVM模型进行优化,然后利用优化后的SVM对人体活动进行分类,最后通过情景分析的方法对错误的识别结果进行修正。实验结果表明,所提方法在加州大学欧文分校（UCI）的人体活动识别数据集（HARUS）上的分类准确率达到了94.2%,高于传统的仅使用模式识别进行分类的方法。     

A comparative study of wavelet families for EEG signal classification

Over the past two decades, wavelet theory has been used for the processing of biomedical signals for feature extraction, compression and de-noising applications. However the question as to which wavelet family is the most suitable for analysis of non-stationary bio-signals is still prevalent among researchers. This paper attempts to find the most useful wavelet function among the existing members of the wavelet families for electroencephalogram signal (EEG) analysis. The EEGs considered for this study belong to both normal as well as abnormal signals like epileptic EEG. Important features such as energy, entropy and standard deviation at different sub-bands were computed using the wavelet functions—Haar, Daubechies (orders 2-10), Coiflets (orders 1-10), and Biorthogonal (orders 1.1, 2.4, 3.5, and 4.4). Feature vectors were used to model and train the Probabilistic Neural Network (PNN) and the classification accuracies were evaluated for each case. The results obtained from PNN classifier were compared with Support Vector Machine (SVM) classifier. From the statistical analysis, it was found that Coiflets 1 is the most suitable candidate among the wavelet families considered in this study for accurate classification of the EEG signals. In this work, we have attempted to improve the computing efficiency as it selects the most suitable wavelet function that can be used for EEG signal processing efficiently and accurately with lesser computational time.     

Kernel ICA: An alternative formulation and its application to face recognition

This paper formulates independent component analysis (ICA) in the kernel-inducing feature space and develops a two-phase kernel ICA algorithm: whitened kernel principal component analysis (KPCA) plus ICA. KPCA spheres data and makes the data structure become as linearly separable as possible by virtue of an implicit nonlinear mapping determined by kernel. ICA seeks the projection directions in the KPCA whitened space, making the distribution of the projected data as non-gaussian as possible. The experiment using a subset of FERET database indicates that the proposed kernel ICA method significantly outperform ICA, PCA and KPCA in terms of the total recognition rate.