基于BP小波网络的故障模式识别

提出了一类新的BP小波网络，该网络采用BP学习算法，可实现信号的小波变换、特征提取和模式分类，具有结构清晰、算法简便的特点。将该网络应用于柴油机的活塞-缸套故障模式识别，并与用一般BP网络识别的结果比较，表明该网络对于非平稳时变振动信号具有很好的模式识别能力。     

基于小波神经网络的光谱数据压缩与分类研究

文中介绍了一种基于小波分析而构造的神经网络模型－小波神经网络,利用它并适当选取网络结构和小波基。实现了对化学物质红外光谱数据的压缩表达和分类,实验表明,网络在大幅度压缩数据的同时能很好地恢复原始光谱,较准确地反映吸收峰的和强度。在分类方面它比其它网络具有更高的分辨率和特征提取能力。     

基于多级小波神经网络的毒品爆炸物能量 色散识别①

利用小波神经网络自适应学习分类的优点,提出将多个小波神经网络并联使用,改进小波网络结构,在每个小波特征空间中确定小波神经元个数和初始化合适的小波基,用多级小波神经网络对毒品爆炸物的X光能量色谱的进行了识别分类。实验表明,用多级小波神经网络可以实现对不同种类毒品爆炸物的识别和鉴定,为X光能量色散技术用于毒品爆炸物的检测和识别提供了一种有效的方法。     

无线传感网络中的目标分类融合

In wireless sensor networks, target classification differs from that in centralized sensing systems because of the distributed detection, wireless communication and limited resources. We study the classification problem of moving vehicles in wireless sensor networks using acoustic signals emitted from vehicles. Three algorithms including wavelet decomposition, weighted k-nearest-neighbor andDempster-Shafer theory are combined in this paper. Finally, we use real world experimental data to validate the classification methods. The result shows that wavelet based feature extraction method can extract stable features from acoustic signals. By fusion with Dempster's rule, the classification performance is improved.     

Wavelet packet neural networks for texture classification

Texture can be defined as a local statistical pattern of texture primitives in observer’s domain of interest. Texture classification aims to assign texture labels to unknown textures, according to training samples and classification rules. This paper describes the usage of wavelet packet neural networks (WPNN) for texture classification problem. The proposed schema composed of a wavelet packet feature extractor and a multi-layer perceptron classifier. Entropy and energy features are integrated wavelet feature extractor. The performed experimental studies show the effectiveness of the WPNN structure. The overall success rate is about 95%.     

A deep stacked wavelet auto-encoders to supervised feature extraction to pattern classification

The major issue in pattern classification is in the extraction of features in the training phase. The focus of this work is on combining the ability of wavelet networks and the deep learning techniques to propose a new supervised feature extraction method to pattern classification. This new approach allows the classification of all classes of the dataset by the reconstruction of a Deep Stacked wavelet Auto-Encoder. This Network is obtained after a series of wavelet Auto-Encoders followed by a Softmax classifier at the last layer. Finally, a fine-tuning is applied for the improvement of our result using a back propagation algorithm. Our approach is tested with different image datasets which are the COIL-100, the APTI and the ImageNet datasets and is also tested with two other audio corpuses that contain Arabic words and French words. The experimental test demonstrates the efficiency of our network for image and audio classification compared to other methods.     

Neural and Wavelet Network Models for Financial Distress Classification

This work analyzes the use of linear discriminant models, multi-layer perceptron neural networks and wavelet networks for corporate financial distress prediction. Although simple and easy to interpret, linear models require statistical assumptions that may be unrealistic. Neural networks are able to discriminate patterns that are not linearly separable, but the large number of parameters involved in a neural model often causes generalization problems. Wavelet networks are classification models that implement nonlinear discriminant surfaces as the superposition of dilated and translated versions of a single “mother wavelet” function. In this paper, an algorithm is proposed to select dilation and translation parameters that yield a wavelet network classifier with good parsimony characteristics. The models are compared in a case study involving failed and continuing British firms in the period 1997–2000. Problems associated with over-parameterized neural networks are illustrated and the Optimal Brain Damage pruning technique is employed to obtain a parsimonious neural model. The results, supported by a re-sampling study, show that both neural and wavelet networks may be a valid alternative to classical linear discriminant models.     

基于新颖子波变换的高光谱遥感图像特征提取

提出了一种新颖的用于高光谱遥感图像特征提取的子波变换算法.与二进小波变换按恒Q准则划分频域不同的是,该算法通过改变相邻子波的带宽比,可以实现更为灵活的频域划分.采用子波能量的离散余弦变换作为特征矢量,然后进行无监督C均值聚类实验和有监督RBF(径向基函数)神经网络分类实验.实验结果表明,子波变换能量的离散余弦变换特征可以有效地描述光谱曲线特征,且正确分类率高于传统的小波变换.     

Power signal classification using dynamic wavelet network

A new approach to classification of non-stationary power signals based on dynamic wavelet has been considered. This paper proposes a model for non-stationary power signal disturbance classification using dynamic wavelet networks (DWN). A DWN is a combination of two sub-networks consisting of a wavelet layer and adaptive probabilistic network. The DWN has the capability of automatic adjustment of learning cycles for different classes of signals, for minimizing error. DWN models are specifically suitable for application in dynamic environments with time varying non-stationary power signals. The test results showed accurate classification, fast and adaptive learning mechanism, fast processing time and overall model effectiveness in classifying various non-stationary power signals. The classification result of the DWN has been compared with that of the probabilistic neural network (PNN).     

小波神经网络在农药荧光光谱识别中的应用

对于结构非常相似的农药,它们的荧光光谱也非常相似并且在很宽波长范围内相互重叠.传统的荧光光谱分析法很难对其进行分类识别.一种基于小波分析而构造的新型神经网络--小波神经网络是利用它并适当选取网络结构和小波基,实现了对卡死克、盖虫散和吡虫啉三种农药荧光光谱的分类识别.实验表明,小波神经网络对光谱间的细微结构差别具有良好的识别能力.通过比较发现,在分类识别方面小波神经网络比BP网络具有更高的分辨率及较少的训练次数.     

基于小波神经网络的心电诊断算法的研究

研究了一种基于小波神经网络的心电图室性早搏和正常窦性心律分类算法.首先对MIT-BIH标准数据库进行室性早搏和正常窦性心律样本的提取与标准化,然后应用小波神经网络建立分类模型.利用小波变换的波形检测和特征提取特点以及人工神经网络的自我学习能力,通过大量的心电图样本训练后,使网络不仅对训练样本有较高的分辨率(97.5%),而且对未训练过的样本也有较好的分辨率(95.1%).仿真结果表明,算法计算简单、实现容易,适用于心电图的分类.     

Wavelet transform-based feature extraction for ultrasonic flaw signal classification

In this paper, we present automatic classification models for ultrasonic flaw signals acquired from carbon-fiber-reinforced polymer specimens. Different state-of-the-art strategies based on wavelet transform are utilized for feature extraction. Furthermore, a wavelet packet transform-based local energy feature extraction method is proposed to solve the deficiencies of the existing methods. Artificial neural networks and support vector machines are trained to validate the effectiveness of different feature extraction methods for flaw signal classification. Experimental results show that the proposed method can extract reliable features to effectively classify the different ultrasonic flaw signals with high accuracy.     

An intelligent system using adaptive wavelet entropy for automatic analog modulation identification

In this paper, an intelligent analog modulation identification system is presented for interpretation of the analog modulated signals. This paper especially deals with combination of the feature extraction and classification for analog modulated signals. The analog modulated signals used in this study are six types (AM, DSB, USB, LSB, FM, and PM). Here, a discrete wavelet neural network-adaptive wavelet entropy (DWNN-ANE) model is used, which consists of two layers: discrete wavelet-adaptive wavelet entropy and multi-layer perceptron neural networks for intelligent analog modulation identification. The discrete wavelet layer is used for adaptive feature extraction in the time-frequency domain and is composed of DWT and adaptive wavelet entropy. The performance of the used system is evaluated by using total 1080 analog modulated signals. These test results show the effectiveness of the used intelligent system presented in this paper. The rate of correct classification is about 98.34% for the sample analog modulated signals.     

A new method for expert target recognition system: Genetic wavelet extreme learning machine (GAWELM)

In last year’s, the expert target recognition has been become very important topic in radar literature. In this study, a target recognition system is introduced for expert target recognition (ATR) using radar target echo signals of High Range Resolution (HRR) radars. This study includes a combination of an adaptive feature extraction and classification using optimum wavelet entropy parameter values. The features used in this study are extracted from radar target echo signals. Herein, a genetic wavelet extreme learning machine classifier model (GAWELM) is developed for expert target recognition. The GAWELM composes of three stages. These stages of GAWELM are genetic algorithm, wavelet analysis and extreme learning machine (ELM) classifier. In previous studies of radar target recognition have shown that the learning speed of feedforward networks is in general much slower than required and it has been a major disadvantage. There are two important causes. These are: (1) the slow gradient-based learning algorithms are commonly used to train neural networks, and (2) all the parameters of the networks are fixed iteratively by using such learning algorithms. In this paper, a new learning algorithm named extreme learning machine (ELM) for single-hidden layer feedforward networks (SLFNs) Ahern et al., 1989, Al-Otum and Al-Sowayan, 2011, Avci et al., 2005a, Avci et al., 2005b, Biswal et al., 2009, Frigui et al., in press, Cao et al., 2010, Guo et al., 2011, Famili et al., 1997, Han and Huang, 2006, Huang et al., 2011, Huang et al., 2006, Huang and Siew, 2005, Huang et al., 2009, Jiang et al., 2011, Kubrusly and Levan, 2009, Le et al., 2011, Lhermitte et al., in press, Martínez-Martínez et al., 2011, Matlab, 2011, Nelson et al., 2002, Nejad and Zakeri, 2011, Tabib et al., 2009, Tang et al., 2011, which randomly choose hidden nodes and analytically determines the output weights of SLFNs, to eliminate the these disadvantages of feedforward networks for expert target recognition area. Then, the genetic algorithm (GA) stage is used for obtaining the feature extraction method and finding the optimum wavelet entropy parameter values. Herein, the optimal one of four variant feature extraction methods is obtained by using a genetic algorithm (GA). The four feature extraction methods proposed GAWELM model are discrete wavelet transform (DWT), discrete wavelet transform–short-time Fourier transform (DWT–STFT), discrete wavelet transform–Born–Jordan time–frequency transform (DWT–BJTFT), and discrete wavelet transform–Choi–Williams time–frequency transform (DWT–CWTFT). The discrete wavelet transform stage is performed for optimum feature extraction in the time–frequency domain. The discrete wavelet transform stage includes discrete wavelet transform and calculating of discrete wavelet entropies. The extreme learning machine (ELM) classifier is performed for evaluating the fitness function of the genetic algorithm and classification of radar targets. The performance of the developed GAWELM expert radar target recognition system is examined by using noisy real radar target echo signals. The applications results of the developed GAWELM expert radar target recognition system show that this GAWELM system is effective in rating real radar target echo signals. The correct classification rate of this GAWELM system is about 90% for radar target types used in this study.     

Wavelet entropy and neural network for text-independent speaker identification

In the present study, the techniques of wavelet transform (WT) and neural network were developed for speech based text-independent speaker identification. The first five formants in conjunction with the Shannon entropy of wavelet packet (WP) upon level four features extraction method was developed. Thirty-five features were fed to feed-forward backpropagation neural networks (FFPBNN) for classification. The functions of features extraction and classification are performed using the wavelet packet and formants neural networks (WPFNN) expert system. The declared results show that the proposed method can make an effectual analysis with average identification rates reaching 91.09. Two published methods were investigated for comparison. The best recognition rate selection obtained was for WPFNN. Discrete wavelet transform (DWT) was studied to improve the system robustness against the noise of −2 dB.     

基于小波变换和ART网络的手写数字识别

由于小波变换能有效地提取字符的结构特征，自适应共振(ART)网络有很好的学习能力。将二者结合起来，用小波变换抽取特征、用自适应共振ART网络作模式分类器来识别手写数字。实验证明该方法有很高的识别率，能够有效地进行手写数字的分类，可以满足实际应用。     

基于小波网络和多模块网络的数字识别

本文研究一种新的数字识别方法,这种方法用小波神经网络抽取特征、用多模块结构神经网络作模式分类器。小波分解的函数近似能力和人工神经网络的学习能力结合起来形成的小波神经网络,有着良好的特征描述性能,可用作特征抽取工具。多模块结构的神经网络将一个k类的模式分类问题转换为k个互相独立的2类分类问题。这种结构将一个复杂的分类问题化解为多个简单的分类问题,各个模块互相并联,各自负责一种模式的识别。用这种修改过的多模块结构网络的BP训练方法,可加速训练和提高训练精度,并且各模块可互相独立地进行训练。用美国NIST数字样本进行训练及测试,结果良好。这种方法可用于更广泛的平面图形识别。     

Impact of different saturation encoding modes on object classification using a BP wavelet neural network

Wavelet neural networks have been successfully applied to object classification due to their unique various advantages. The wavelet neural network used in this paper is a type of back-propagation algorithm-learning wavelet neural network. The log-sigmoid function and wavelet basis function satisfying the frame condition are employed as an activation function in the output and hidden layers, respectively, and the entropy error function is also used to accelerate the learning speed. The log-sigmoid function has two saturated values, 0 and 1, which are the value of the function at a point whose value changes slightly as the independent variable changes at a somewhat wide range. Using this property of the saturated values and simplifying the mathematical model of neural network classification, we may mathematically prove that using different saturated values to encode the modes can affect the training error, generalization ability, and anti-noise ability of the wavelet neural network, in turn resulting in differences in classification accuracy. The saturated and unsaturated value-encoding modes will both decrease the generalization ability of the network and reduce the classification accuracy due to excessively strong or weak anti-noise ability. Therefore, we propose a type of moderate saturated-value encoding mode, in which the anti-noise ability, the gradient, and error in training process are more moderate than the other two encodings, so that this kind of encoding mode can facilitate a stronger generalization ability and higher classification accuracy for the wavelet neural network, and which have been affirmed in the classification experiments of CHRIS remote-sensing imagery of the Huanghe estuary coastal wetland and SIR-C remote-sensing image of sea ice in the Labrador Gulf, and reaffirmed in classification experiments where noise was added to the test data.     

Wavelet packet energy, Tsallis entropy and statistical parameterization for support vector-based and neural-based classification of mammographic regions

This work develops a support vector and neural-based classification of mammographic regions by applying statistical, wavelet packet energy and Tsallis entropy parameterization. From the first four wavelet packet decomposition levels, four different feature sets were evaluated using two-sample Kolmogorov-Smirnov test (KS-test) and, in one case, principal component analysis (PCA). Feature selection was performed applying a hybrid scheme integrating non-parametric KS-test, correlation analysis, a logistic regression (LR) model and sequential forward selection (SFS). The top selected features (depending on the selected wavelet decomposition level) produced the best classification performances in comparison to other well-known feature selection methods. The classification of the data was carried out using several support vector machine (SVM) schemes and multi-layer perceptron (MLP) neural networks. The new set of features improved significantly the classification performance of mammographic regions using conventional SVMs and MLPs.     

轴承故障融合诊断方法

针对传统人工神经网络在故障诊断中应用的局限性 ,提出一种基于小波变换、遗传算法与神经网络的融合故障诊断方法。该方法先用小波变换对原始采样信号进行特征提取 ,再用遗传算法优化选择最为重要的特征作为神经网络的输入参数。最后 ,由神经网络进行状态识别和特征分类。这样不仅减少网络训练时间 ,降低网络计算量 ,而且有效提高分类的准确性及故障诊断的可靠性。轴承故障诊断实验结果表明 ,该方法是有效的。