基于非监督学习神经网络的自动调制识别研究与实现

以非监督学习神经网络为主要研究对象,描述自组织网络的基本模型,分析传统自组织网络的训练算法,提出了一种基于自组织特征映射SOFM(Self-Organizing Feature Map)神经网络的通信信号自动调制识别方法。方法改进了训练算法中的学习率函数和邻域函数,提高了算法的收敛速度和性能,并将其应用在通信信号调制识别中。仿真实验检验基于SOFM神经网络的调制识别方法的性能,并与后向反馈(BP)神经网络加以比较,结果表明SOFM神经网络的调制识别方法具有较高的识别精度,改进后的训练算法提高了识别的有效性。     

Genetic design of biologically inspired receptive fields for neural pattern recognition

This paper proposes a new method for the design, through simulated evolution, of biologically inspired receptive fields in feedforward neural networks (NNs). The method is intended to enhance pattern recognition performance by creating new neural architectures specifically tuned for a particular pattern recognition problem. It proposes a combined neural architecture composed of two networks in cascade: a feature extraction network (FEN) followed by a neural classifier. The FEN is composed of several layers with receptive fields constructed by additive superposition of excitatory and inhibitory fields. A genetic algorithm (GA) is used to select receptive field parameters to improve classification performance. The parameters are receptive field size, orientation, and bias as well as the number of different receptive fields in each layer. Based on a random initial population where each individual represents a different neural architecture, the GA creates new enhanced individuals. The method is applied to handwritten digit classification and face recognition. In both problems, results show strong dependency between NN classification performance and receptive field architecture. GA selected parameters of the receptive fields produced improvements in the classification performance on the test set up to 90.8% for the problem of handwritten digit classification and up to 84.2% for the face recognition problem. On the same test sets, results were compared advantageously to standard feedforward multilayer perceptron (MLP) NNs where receptive fields are not explicitly defined. The MLP reached a maximum classification performance of 84.9% and 77.5% in both problems, respectively.     

基于BP神经网络的人脸识别方法

人脸自动识别是计算机模式识别领域的一个活跃课题,有着十分广泛的应用前景。文中提出了基于ＢＰ神经网络的人脸识别方法,论述了人脸图像矢量的特征压缩问题、网络隐含层神经元数选取问题、网络输入矢量的标准化处理问题以及网络连接权值选取问题。对于１８人、每人１２幅图像组成的脸图像数据库做识别实验,实验结果表明文中所设计的神经网络分类器比常用的最近邻分类器有效地降低了识别错误率。     

An adaptive neural networks formulation for the two-dimensional principal component analysis

This study, for the first time, developed an adaptive neural networks (NNs) formulation for the two-dimensional principal component analysis (2DPCA), whose space complexity is far lower than that of its statistical version. Unlike the NNs formulation of principal component analysis (PCA, i.e., 1DPCA), the solution with lower iteration in nature aims to directly deal with original image matrices. We also put forward the consistence in the conceptions of ‘eigenfaces’ or ‘eigengaits’ in both 1DPCA and 2DPCA neural networks. To evaluate the performance of the proposed NN, the experiments were carried out on AR face database and on 64 × 64 pixels gait energy images on CASIA(B) gait database. The less reconstruction error was exploited using the proposed NN in the condition of a large sample set compared to adaptive estimation of learning algorithms for NNs of PCA. On the contrary, if the sample set was small, the proposed NN could achieve a higher residue error than PCA NNs. The amount of calculation for the proposed NN here could be smaller than that for the PCA NNs on the feature extraction of the same image matrix, which represented an efficient solution to the problem of training images directly. On face and gait recognition tasks, a simple nearest neighbor classifier test indicated a particular benefit of the neural network developed here which serves as an efficient alternative to conventional PCA NNs.     

基于卷积特征和贝叶斯分类器的人脸识别

为解决传统人脸识别算法特征提取困难的问题,提出了基于卷积特征和贝叶斯分类器的人脸识别方法,利用卷积神经网络提取人脸特征,通过主成分分析法对特征降维,最后利用贝叶斯分类器进行判别分类,在ORL（olivetti research laboratory）人脸库上进行实验,获得了99.00%的识别准确率。实验结果表明,卷积神经网络提取的人脸图像特征具有很强的辨识度,与PCA（principal component analysis）和贝叶斯分类器结合之后可有效提高人脸识别的准确率。     

基于生成对抗网络的遮挡表情识别

针对实际应用中局部遮挡会影响人脸表情识别,提出一种基于生成对抗网络（GAN）的表情识别算法。先对遮挡人脸图像填补修复,再进行表情识别。其中GAN的生成器由卷积自动编码机构成,与鉴别器的对抗学习使得生成的人脸图像更加逼真;由卷积神经网络构成的鉴别器具有良好的特征提取能力,添加多分类层构成了表情分类器,避免了重新计算图像特征。为了解决训练样本不足的问题,将CelebA人脸数据集用于训练人脸填补修复,同时表情分类器的特征提取部分得到了预训练。在CK+数据集上的实验证明,填补后的人脸图像真实连贯,并取得了较高的表情识别率,尤其提高了人脸大面积遮挡的识别率。     

基于Sanger神经网络的TDDM-BOC信号组合码序列盲估计

针对低信噪比（SNR）下时分数据调制二进制偏移载波调制信号（TDDM-BOC）的组合码序列盲估计问题,提出一种基于Sanger神经网络（Sanger NN）的新方法。首先将已分段的信号作为输入信号并利用Sanger NN提取各主分量的权值向量;然后通过其多次输入反复训练权值向量,直至权值向量达到收敛;最终利用各个权值向量的符号函数重建信号的组合码序列,实现TDDM-BOC组合码序列的盲估计。此外,采用最优变步长的方法来提高收敛速度。理论分析和仿真实验表明,Sanger NN可以实现-20.9~0 dB信噪比下TDDM-BOC信号组合码序列的盲估计,且其复杂度明显低于传统奇异值分解（SVD）法和自适应特征提取的在线无监督学习神经网络（LEAP）;尽管Sanger NN收敛所需数据组数大于LEAP,但收敛时间明显少于LEAP算法。     

基于SOFM网络的聚类分析

基于自组织特征映射网络的聚类分析,是在神经网络基础上发展起来的一种新的非监督聚类方法,分析了基于自组织特征映射网络聚类的学习过程,分析了权系数自组织过程中邻域函数和学习步长的一般取值问题,给出了基于自组织特征映射网络聚类实现的具体算法,并通过实际示例测试,证实了算法的正确性。     

Efficient MLP constructive training algorithm using a neuron recruiting approach for isolated word recognition system

This paper describes an efficient constructive training algorithm using a Multi Layer Perceptron (MLP) neural network dedicated for Isolated Word Recognition (IWR) systems. Incremental training procedure was employed and this approach was based on novel hidden neurons recruiting for a single hidden-layer. During Neural Network (NN) training phase, the number of pronunciation samples extracted from the Training Data (TD) was sequentially increased. Optimal structure of the NN classifier with optimized TD size was obtained using this proposed MLP constructive training algorithm.     

基于条件深度卷积生成对抗网络的图像识别方法

生成对抗网络（Generative adversarial networks,GAN）是目前热门的生成式模型.深度卷积生成对抗网络（Deep convolutional GAN,DCGAN）在传统生成对抗网络的基础上,引入卷积神经网络（Convolutional neural networks,CNN）进行无监督训练;条件生成对抗网络（Conditional GAN,CGAN）在GAN的基础上加上条件扩展为条件模型.结合深度卷积生成对抗网络和条件生成对抗网络的优点,建立条件深度卷积生成对抗网络模型（Conditional-DCGAN,C-DCGAN）,利用卷积神经网络强大的特征提取能力,在此基础上加以条件辅助生成样本,将此结构再进行优化改进并用于图像识别中,实验结果表明,该方法能有效提高图像的识别准确率.     

Adaptive resonance neural classifier for identification of gases/odours using an integrated sensor array

A new approach to intelligent gas sensor (IGS) design using a classifier based on adaptive resonance theory (ART) artificial neural network (ANN) is presented. Using published data of sensor arrays fabricated and characterised at our laboratory, we demonstrate excellent gas/odour identification performance of our classifier for a 4-gas, 4-sensor system to identify individual gas/odour. Since the ART neural network is a self-organising classifier trained in the unsupervised mode, it avoids the drawbacks associated with static feedforward neural networks trained with a locally optimal backpropagation-type training algorithms applied by researchers in the recent past. The ART neural network offers easy implementability and real time performance in addition to giving excellent classification accuracy as demonstrated by our experiments.     

基于卷积神经网络多层特征提取的目标识别

目标识别一直是人工智能领域的热点问题. 为了提高目标识别的效率,提出了基于卷积神经网络多层特征提取的目标识别方法. 该方法将图像输入卷积神经网络进行训练,在网络的每个全连接层分别进行特征提取,将得到的特征依次输入到分类器,对输出结果进行比较. 选取经过修正线性单元relu函数激活的低层全连接层作为特征提取层,比选取高层全连接层特征提取的识别率高. 本文构建了办公用品数据集,实现了基于卷积神经网络多层特征提取的办公用品识别系统. 选择AlexNet卷积神经网络模型的relu6层作为特征选取层,选择最优训练图像数量和最优分类器构建系统,从而证明了该方法的可行性.     

Hybrid neural network and genetic algorithm based machining feature recognition

In this research, neural networks (NNs) and genetic algorithms (GAs) are used together in a hybrid approach to reduce the computational complexity of feature recognition problem. The proposed approach combines the characteristics of evolutionary technique and NN to overcome the shortcomings of feature recognition problem. Consideration is given to reduce the computational complexity of network with specific interest to design the optimum network architecture using GA input selection approach. In order to evaluate the performance of the proposed system, experimental results are compared with previous NN based feature recognition research.     

When eigenfaces are combined with wavelets

This paper presents a novel and interesting combination of wavelet techniques and eigenfaces to extract features for face recognition. Eigenfaces reduce the dimensions of face vectors while wavelets reveal information that is unavailable in the original image. Extensive experiments have been conducted to test the new approach on the ORL face database, using a radial basis function neural network classifier. The results of the experiments are encouraging and the new approach is a step forward in face recognition.     

特征脸及其改进方法在人脸识别中的比较研究

人脸识别是生物特征识别技术中一个非常活跃的课题,目前已取得了很多研究成果。特征脸法是一种常用的人脸特征提取和识别方法。对传统的特征脸方法进行改进,可以提高人脸正确识别率、缩短识别时间。本文对特征脸及其改进方法做了理论和实验比较,分析了各自的优缺点。     

Human face recognition using fuzzy multilayer perceptron

In this work a novel method for human face recognition that is based on fuzzy neural network has been presented. Here, Gabor wavelet transformation is used for extraction of features from face images as it deals with images in spatial as well as in frequency domain to capture different local orientations and scales efficiently. In face recognition problem multilayer perceptron (MLP) has already been adopted owing to its efficiency, but it does not capture overlapping and nonlinear manifolds of faces which exhibit different variations in illumination, expression, pose, etc. A fuzzy MLP on the other hand performs better than an MLP because fuzzy MLP can identify decision surfaces in case of nonlinear overlapping classes, whereas an MLP is restricted to crisp boundaries only. In the present work, a new approach for fuzzification of the feature sets obtained through Gabor wavelet transforms has been discussed. The feature vectors thus obtained are classified using a newly designed fuzzified MLP. The system has been tested on a composite database (DB-C) consisting of the ORL face database and another face database created for this purpose and a recognition rate of 97.875% with fuzzy MLP against a recognition rate of only 81.25% with MLP whose feature vectors were also obtained through same Gabor wavelet transforms has been obtained.     

GA-BP神经网络在下肢运动步态识别中的应用研究

为了提高下肢表面肌电信号步态识别的准确性,提出了一种基于遗传算法（GA）优化的BP神经网络分类器设计方法。首先,对采集的下肢表面肌电信号进行小波滤波及特征值提取,其次,构造基于GA优化的BP神经网络分类器,然后,以提取的表面肌电信号特征作为输入对分类器进行训练,最后利用训练好的分类器进行测试。实验结果表明,基于GA优化的BP神经网络分类器能成功识别下肢正常行走的五个步态,平均识别率达到98%以上,效果明显优于BP神经网络分类器的识别效果。     

Shared feature extraction for nearest neighbor face recognition.

In this paper, we propose a new supervised linear feature extraction technique for multiclass classification problems that is specially suited to the nearest neighbor classifier (NN). The problem of finding the optimal linear projection matrix is defined as a classification problem and the Adaboost algorithm is used to compute it in an iterative way. This strategy allows the introduction of a multitask learning (MTL) criterion in the method and results in a solution that makes no assumptions about the data distribution and that is specially appropriated to solve the small sample size problem. The performance of the method is illustrated by an application to the face recognition problem. The experiments show that the representation obtained following the multitask approach improves the classic feature extraction algorithms when using the NN classifier, especially when we have a few examples from each class.     

基于模糊神经网络的网络业务分类研究

该文利用神经网络的自学习能力和模糊逻辑的动态性和及时性等特点,将模糊逻辑和神经网络有机地结合起来,构造出了四层模糊神经网络,并用训练神经网络的相应学习算法训练网络,将该模型用于网络业务源特征提取与分类的研究中,并与单纯的神经网络算法相比较。计算机仿真结果表明,模糊神经网络方法比神经网络算法更优越,该文的研究结果为解决网络业务源特征提取与分类奠定了基础。     

基于改进深度孪生网络的分类器及其应用

孪生神经网络由两组共享参数的孪生神经网络组成,可对高维度非线性的数据进行低维度映射,其在低维特征空间中变得可分。利用其优异的相似度计算性能,针对像交通标志识别这样具有复杂环境条件的分类问题,提出并设计基于孪生神经网络结构的高效分类器。采用卷积神经网络作为其基本构成,运用max-pooling,dropout等技术形成特征提取所需的多尺度卷积神经网络。同时辅助以空间变换器网络来进一步提高识别的准确率。通过对GTSRB交通标志数据集进行测试,其识别的准确率达到了99.40%。该分类器方法同时具备了结构简单、训练时间短、准确率高以及识别速度快的优点。