基于BP神经网络的参数自整定PID控制器仿真研究

PID控制是迄今为止在过程控制中应用最为广泛的控制方法,但在实际应用中,其参数整定仍未得到较好的解决。把神经网络技术应用在PID控制中,充分利用神经网络具有非线性函数逼近能力,构造神经网络PID自整定控制器,并通过MATLAB仿真试验,取得较好的效果。     

An information fusion based method for liver classification using texture analysis of ultrasound images

This paper presents a method for classification of liver ultrasound images based on texture analysis. The proposed method uses a set of seven texture features having high discriminative power which can be used by radiologists to classify the liver. Feature extraction is carried out using the following texture models: Spatial Gray Level Co-occurrence Matrix, Gray Level Difference Statistics, First order Statistics, Fourier Power Spectrum, Statistical Feature Matrix, Law’s Texture Energy Measures and Fractal Features. Based upon the results of Linear Discriminative Analysis (LDA) followed by box-plot analysis and Pearson’s correlation coefficient, 7 best features from a set of 35 features are selected. These selected features are then fused using a linear classifier. The novelty of the proposed method is that, it combines the best features from different texture domains along with their weights and ‘weighted z-score’ values. Subsequently, these values are used to compute a discriminative index for liver classification. The results show that this method has overall classification accuracy of 95% and low computational complexity.     

基于支持向量机的径向基网络结构优化

为了解决径向基网络（RBF NN）结构设计的随机性,进一步优化RBF网络性能,提出一种基于支持向量机（SVM）的径向基网络结构优化方法。通过训练得到的SVM确定径向基网络的隐层节点个数、隐层权值和阈值;同时利用SVM对输入向量进行特征变换,进一步对输入向量进行维数约简。通过齿轮箱的故障诊断实验表明,优化后的RBF网络具有更精简、稳定的网络结构,能得到更准确的诊断结果。     

BP Neural Network Classification of Remote Sensing Images based on DT\|CWT Decomposition

In order to solve the ambiguity and uncertainty of high resolution multi\|spectral remote sensing image classification and to better overcome the influence of noise,a new BPNN（Back Propagation Neural Network）classification method of multi\|spectral image,based on DT\|CWT decomposition,is presented in this paper.First,the NDVI and texture features of the image are extracted to reduce the classification uncertainty caused by the problem of different objects having the same spectrum and the same objects having different spectrum in the image,then,the original spectral band,NDVI and texture features of the image are decomposed by DT\|CWT to extract the Low\|frequency information of the image,as well as to reduce the image noise and the presence of “salt and pepper” in the classification.Finally,the extracted low\|frequency sub\|graphs are input to the BP neural network and classified according to the trained network to obtain the final classification result.The results of the comparison show that the proposed method with less miscellaneous points has stronger regional consistency,higher classification accuracy and better robustness.     

基于听觉感知和概率神经网络的语音识别模型

提出了一种基于Bark子波变换和概率神经网络（PNN）的语音识别模型。利用符合人耳听觉特性的Bark滤波器组进行信号重构并提取语音特征,然后利用训练好的概率神经网络进行识别。通过训练大量语音样本来构成语音识别库,并建立综合识别系统。实验结果表明该方法与传统的LPCC/DTW和MFCC/DWT方法相比,识别率分别提高了14.9%和10.1%,达到了96.9%的识别率。     

用于肺炎图像分类的优化卷积神经网络方法

目前,卷积神经网络（CNN）开始应用在肺炎分类领域。针对层数较浅、结构较为简单的卷积网络对肺炎识别的准确率难以提高的情况,采用深度学习方法,并针对采用深度学习方法时常常需要消耗大量的系统资源,导致卷积网络难以在用户端部署的问题,提出一种使用优化的卷积神经网络的分类方法。首先,根据肺炎图像的特征,选择具有良好图像分类性能的AlexNet与InceptionV3模型;然后,利用医学影像特点对层次更深、结构更加复杂的InceptionV3模型进行预训练;最后,通过知识蒸馏的方法,将训练好的"知识"（有效信息）提取到AlexNet模型中,从而实现在减少系统资源占用的同时,提高准确率的效果。实验数据表明,使用知识蒸馏后,AlexNet模型的准确率、特异性与灵敏度分别提高了4.1、7.45、1.97个百分点,且对图像处理器（GPU）占用相比InceptionV3模型减小了51个百分点。     

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.     

基于神经网络的电信客户流失预测主题建模及实现

客户流失管理是电信运营商通过对客户需求满意度调查进行有针对性挽留客户的一个重要方法，其中最关键的就是对客户流失行为做出预测。提出了一种基于神经网络的客户流失预测模型。根据行业专家经验值选取分析变量，通过神经网络计算分析变量的权值，建立客户流失预测模型并对客户流失趋势进行预测。该方法与决策树和贝叶斯网络等算法相比，通过使用两次神经网络，从原始数据上千个属性中提炼出与客户流失度相关性较大的属性，分析出的影响流失属性更利于下一步的客户挽留工作。     

一种基于PCA-BP神经网络的示例优选方法

在音频示例检索的研究中,针对示例数据量大而导致计算代价大、检索时间长和噪声鲁棒性差等问题,提出了一种基于主成分分析（PCA）和BP神经网络（BPNN）的示例优选方法。以信号鲁棒性评分为依据构建数据集合,使用主成分分析得到段级特征,消除数据冗余,减少输入变量,最后利用BPNN对保留成分进行建模预测。用PCA-BPNN模型对实验数据进行了验证性测试和分析,结果表明,该方法可以准确而高效地从一段音频中选取鲁棒性好的示例。     

基于多尺度分析与神经网络的需水量预测

采用小波多尺度分解的方法,将需水量时间序列分解为多个较平稳的细节子序列和一个趋势序列,再利用BP神经网络对分解后的各序列进行预测,把预测后的序列聚合重构,得到预测结果。以新疆石河子地区的需水量为例对该方法作了验证。表明多尺度分析与神经网络耦合预测,比单一BP神经网络预测精度更高,可满足实际需要。     

Using an unsupervised approach of Probabilistic Neural Network (PNN) for land use classification from multitemporal satellite images

The aim of this work is to develop an unsupervised approach based on Probabilistic Neural Network (PNN) for land use classification. A time series of high spatial resolution acquired by LANDSAT and SPOT images has been used to firstly generate the profiles of Normalized Difference Vegetation Index (NDVI) and then used for the classification procedure.The proposed method allows the implementation of cluster validity technique in PNN using Ward's method to get clusters. This procedure is completely automatic with no parameter adjusting and instantaneous training, has high ability in producing a good cluster number estimates and provides a new point of view to use PNN as unsupervised classifier. The obtained results showed that this approach gives an accurate classification with about 3.44% of error through a comparison with the real land use and provides a better performance when comparing to usual unsupervised classification methods (fuzzy c-means (FCM) and K-means).     

基于卷积神经网络和代价敏感的不平衡图像分类方法

针对不平衡图像分类中少数类查全率低、分类结果总代价高,以及人工提取特征主观性强而且费时费力的问题,提出了一种基于Triplet-sampling的卷积神经网络（Triplet-sampling CNN）和代价敏感支持向量机（CSSVM）的不平衡图像分类方法——Triplet-CSSVM。该方法将分类过程分为特征学习和代价敏感分类两部分。首先,利用误差公式为三元损失函数的卷积神经网络端对端地学习将图像映射到欧几里得空间的编码方法;然后,结合采样方法重构数据集,使其分布平衡化;最后,使用CSSVM分类算法给不同类别赋以不同的代价因子,获得最佳代价最小的分类结果。在深度学习框架Caffe上使用人像数据集FaceScrub进行实验。实验结果表明,所提方法在1∶3的不平衡率下,与VGGNet-SVM方法相比,少数类的精确率提高了31个百分点,召回率提高了71个百分点。     

A hybrid radial basis function and data envelopment analysis neural network for classification

We propose a hybrid radial basis function network-data envelopment analysis (RBFN-DEA) neural network for classification problems. The procedure uses the radial basis function to map low dimensional input data from input space ℜ to a high dimensional ℜ⁺ feature space where DEA can be used to learn the classification function. Using simulated datasets for a non-linearly separable binary classification problem, we illustrate how the RBFN-DEA neural network can be used to solve it. We also show how asymmetric misclassification costs can be incorporated in the hybrid RBFN-DEA model. Our preliminary experiments comparing the RBFN-DEA with feed forward and probabilistic neural networks show that the RBFN-DEA fares very well.     

Fully automatic and segmentation-robust classification of breast tumors based on local texture analysis of ultrasound images

Region of interest (ROI) is a region used to extract features. In breast ultrasound (BUS) image, the ROI is a breast tumor region. Because of poor image quality (low SNR (signal/noise ratio), low contrast, blurry boundaries, etc.), it is difficult to segment the BUS image accurately and produce a ROI which precisely covers the tumor region. Due to the requirement of accurate ROI for feature extraction, fully automatic classification of BUS images becomes a difficult task. In this paper, a novel fully automatic classification method for BUS images is proposed which can be divided into two steps: “ROI generation step” and “ROI classification step”. The ROI generation step focuses on finding a credible ROI instead of finding the precise tumor location. The ROI classification step employs a novel feature extraction and classification strategy. First, some points in the ROI are selected as the “classification checkpoints” which are evenly distributed in the ROI, and the local texture features around each classification checkpoint are extracted. For each ROI, all the classification checkpoints are classified. Finally, the class of the BUS image is determined by analyzing every classification checkpoint in the corresponding ROI. Both steps were implemented by utilizing a supervised texture classification approach. The experiments demonstrate that the proposed method is very robust to the segmentation of BUS images, and very effective and useful for classifying breast tumors.     

Neural network classifier optimization using Differential Evolution with Global Information and Back Propagation algorithm for clinical datasets

A Computer-Aided Diagnostic (CAD) system that uses Artificial Neural Network (ANN) trained by drawing in the relative advantages of Differential Evolution (DE), Particle Swarm Optimization (PSO) and gradient descent based backpropagation (BP) for classifying clinical datasets is proposed. The DE algorithm with a modified best mutation operation is used to enhance the search exploration of PSO. The ANN is trained using PSO and the global best value obtained is used as a seed by the BP. Local search is performed using BP, in which the weights of the Neural Network (NN) are adjusted to obtain an optimal set of NN weights. Three benchmark clinical datasets namely, Pima Indian Diabetes, Wisconsin Breast Cancer and Cleveland Heart Disease, obtained from the University of California Irvine (UCI) machine learning repository have been used. The performance of the trained neural network classifier proposed in this work is compared with the existing gradient descent backpropagation, differential evolution with backpropagation and particle swarm optimization with gradient descent backpropagation algorithms. The experimental results show that DEGI-BP provides 85.71% accuracy for diabetes, 98.52% for breast cancer and 86.66% for heart disease datasets. This CAD system can be used by junior clinicians as an aid for medical decision support.     

Investigation of engine fault diagnosis using discrete wavelet transform and neural network

An investigation of a fault diagnostic technique for internal combustion engines using discrete wavelet transform (DWT) and neural network is presented in this paper. Generally, sound emission signal serves as a promising alternative to the condition monitoring and fault diagnosis in rotating machinery when the vibration signal is not available. Most of the conventional fault diagnosis techniques using sound emission and vibration signals are based on analyzing the signal amplitude in the time or frequency domain. Meanwhile, the continuous wavelet transform (CWT) technique was developed for obtaining both time-domain and frequency-domain information. Unfortunately, the CWT technique is often operated over a longer computing time. In the present study, a DWT technique which is combined with a feature selection of energy spectrum and fault classification using neural network for analyzing fault signal is proposed for improving the shortcomings without losing its original property. The features of the sound emission signal at different resolution levels are extracted by multi-resolution analysis and Parseval’s theorem [Gaing, Z. L. (2004). Wavelet-based neural network for power disturbance recognition and classification. IEEE Transactions on Power Delivery 19, 1560–1568]. The algorithm is obtained from previous work by Daubechies [Daubechies, I. (1988). Orthonormal bases of compactly supported wavelets. Communication on Pure and Applied Mathematics 41, 909–996.], the“db4”, “db8” and “db20” wavelet functions are adopted to perform the proposed DWT technique. Then, these features are used for fault recognition using a neural network. The experimental results indicated that the proposed system using the sound emission signal is effective and can be used for fault diagnosis of various engine operating conditions.     

Self adaptive growing neural network classifier for faults detection and diagnosis

Fault detection and diagnosis have gained widespread industrial interest in machine monitoring due to their potential advantage that results from reducing maintenance costs, improving productivity and increasing machine availability. This article develops an adaptive intelligent technique based on artificial neural networks combined with advanced signal processing methods for systematic detection and diagnosis of faults in industrial systems based on a classification method. It uses discrete wavelet transform and training techniques based on locating and adjusting the Gaussian neurons in activation zones of training data. The learning (1) provides minimization in the number of neurons depending on cost error function and other stopping criterions; (2) offers rapid training and testing processes; (3) provides accuracy in classification as confirmed by the results on real signals. The method is applied to classify mechanical faults of rotary elements and to detect and isolate disturbances for a chemical process. Obtained results are analyzed, explained and compared with various methods that have been widely investigated for fault diagnosis.     

基于小波变换的分数阶微分算法在肝脏肿瘤CT图像纹理增强中的应用

图像纹理增强过程中容易丢失平滑区域纹理细节，而分数阶微分增强虽然能够非线性保留平滑区域纹理细节，但对频率分辨率敏感。针对这个问题，提出一种基于小波变换的分数阶微分纹理增强算法，应用于平扫计算机断层扫描（CT）图像的肝脏肿瘤区域的纹理增强。首先，通过小波变换将图像感兴趣区分解成多个子带分量；其次，基于分数阶微分定义构造一个带补偿参数的分数阶微分掩膜；最后，使用该掩膜与每个高频子带分量进行卷积并利用小波逆变换重组图像感兴趣区。实验结果表明，该方法在使用较大分数阶次显著增强肿瘤区域的高频轮廓信息的同时，有效地保留了低频平滑的纹理细节：增强后的肝细胞癌区域与原区域相比，信息熵平均增加36.56%，平均梯度平均增加321.56%，平均绝对差值平均为9.287；增强后的肝血管瘤区域与原区域相比，信息熵平均增加48.77%，平均梯度平均增加511.26%，平均绝对差值平均为14.097。     

SVM和ANN在网络安全风险评估中的比较研究

支持向量机和人工神经网络是人工智能方法的两个分支,详细介绍了支持向量机和人工神经网络原理。建立了网络安全评估指标体系,将支持向量机和人工神经网络同时应用于网络安全风险评估的过程中,通过实例比较了两者的评估效果,结果表明了支持向量机在小样本情况下分类正确率普遍高于人工神经网络,具有较好的分类能力和泛化能力;同时在训练时间上也有绝对的优势。实践证实了支持向量机用于网络安全风险评估的有效性和优越性。     

A novel adaptive convolutional neural network for fault diagnosis of hydraulic piston pump with acoustic images

As an essential part of hydraulic transmission systems, hydraulic piston pumps have a significant role in many state-of-the-art industries. Thus, it is important to implement accurate and effective fault diagnosis of hydraulic piston pumps. Owing to the heavy reliance of shallow machine learning models on the expertise and experience of engineers, fault diagnosis based on deep models has attracted significant attention from academia and industry. To construct a deep model with good performance, it is necessary and challenging to tune the hyperparameters (HPs). Since many existing methods focus on manual tuning and use common search algorithms, it is meaningful to explore more intelligent algorithms that can automatically optimize the HPs. In this paper, Bayesian optimization (BO) is employed for adaptive HP learning, and an improved convolutional neural network (CNN) is established for fault feature extraction and classification in a hydraulic piston pump. First, acoustic signals are transformed into time–frequency distributions by a continuous wavelet transform. Second, a preliminary CNN model is built by setting initial HPs. The range of each HP to be optimized is identified. Third, BO is employed to select the optimal combination of HPs. An improved model called CNN-BO is constructed. Finally, the diagnostic efficiency of CNN-BO is analyzed using a confusion matrix and t-distributed stochastic neighbor embedding. The classification performance of different models is compared. It is found that CNN-BO has a higher accuracy and better robustness in fault diagnosis for a hydraulic piston pump. This research will provide a basis for ensuring the reliability and safety of the hydraulic pump.