融合迁移学习的AlexNet神经网络不锈钢焊缝缺陷分类

针对不锈钢焊缝缺陷特征提取存在主观单一性和客观不充分性等问题,提出一种融合迁移学习的AlexNet卷积神经网络模型,用于不锈钢焊缝缺陷的自动分类。首先,由于不锈钢焊缝缺陷数据较为缺乏,通过采用迁移学习对网络前3层冻结,减少网络对输入数据量的要求;对后2层卷积层提取的特征信息批量归一化(batch normalization, BN),以加快网络的收敛速度;并使用带泄露线性整流(leaky rectified linear unit, LeakyReLU)函数对抑制神经元进行激活,从而提高模型的鲁棒性和特征提取能力。结果表明,该模型最终达到了95.12%的准确率, 相比原结构识别精度提高了9.8%。验证了改进后方法能够对裂纹、气孔、夹渣、未熔合和未焊透5类不锈钢焊缝缺陷实现高精度分类。相比现有方法,其识别面更广,精度更高,具有一定的工程实践意义。     

Big Data Analytics: Deep Content-Based Prediction with Sampling Perspective

The world of information technology is more than ever being flooded with huge amounts of data, nearly 2.5 quintillion bytes every day. This large stream of data is called big data, and the amount is increasing each day. This research uses a technique called sampling, which selects a representative subset of the data points, manipulates and analyzes this subset to identify patterns and trends in the larger dataset being examined, and finally, creates models. Sampling uses a small proportion of the original data for analysis and model training, so that it is relatively faster while maintaining data integrity and achieving accurate results. Two deep neural networks, AlexNet and DenseNet, were used in this research to test two sampling techniques, namely sampling with replacement and reservoir sampling. The dataset used for this research was divided into three classes: acceptable, flagged as easy, and flagged as hard. The base models were trained with the whole dataset, whereas the other models were trained on 50% of the original dataset. There were four combinations of model and sampling technique. The F-measure for the AlexNet model was 0.807 while that for the DenseNet model was 0.808. Combination 1 was the AlexNet model and sampling with replacement, achieving an average F-measure of 0.8852. Combination 3 was the AlexNet model and reservoir sampling. It had an average F-measure of 0.8545. Combination 2 was the DenseNet model and sampling with replacement, achieving an average F-measure of 0.8017. Finally, combination 4 was the DenseNet model and reservoir sampling. It had an average F-measure of 0.8111. Overall, we conclude that both models trained on a sampled dataset gave equal or better results compared to the base models, which used the whole dataset.     

Diagnosis of COVID-19 Pneumonia via a Novel Deep Learning Architecture

COVID-19 is a contagious infection that has severe effects on the global economy and our daily life. Accurate diagnosis of COVID-19 is of importance for consultants, patients, and radiologists. In this study, we use the deep learning network AlexNet as the backbone, and enhance it with the following two aspects: 1) adding batch normalization to help accelerate the training, reducing the internal covariance shift; 2) replacing the fully connected layer in AlexNet with three classifiers: SNN, ELM, and RVFL. Therefore, we have three novel models from the deep COVID network (DC-Net) framework, which are named DC-Net-S, DC-Net-E, and DC-Net-R, respectively. After comparison, we find the proposed DC-Net-R achieves an average accuracy of 90.91% on a private dataset (available upon email request) comprising of 296 images while the specificity reaches 96.13%, and has the best performance among all three proposed classifiers. In addition, we show that our DC-Net-R also performs much better than other existing algorithms in the literature.     

基于复杂网络描述的图像深度卷积分类方法

为了在不增加较多计算量的前提下,提高卷积网络模型用于图像分类的正确率,提出了一种基于复杂网络模型描述的图像深度卷积分类方法。首先,对图像进行复杂网络描述,得到不同阈值下的复杂网络模型度矩阵;然后,在图像度矩阵描述的基础上,通过深度卷积网络得到特征向量;最后,根据得到的特征向量进行K近邻（KNN）分类。在ILSVRC2014数据库上进行了验证实验,实验结果表明,所提出的模型具有较高的正确率和较少的迭代次数。     

采用改进型AlexNet的辐射源目标个体识别方法

针对辐射源目标精确识别需求,结合以深度学习为代表的机器学习理论技术,提出将改进型AlexNet作为特征提取器,实现目标细微特征提取固化,形成智能化识别网络模型。以广播式自动相关监视（ADS-B）信号为实验对象,在机场实地采集了13个目标的ADS-B脉冲信号数据作为辐射源目标个体识别的训练和测试样本,利用AlexNet和改进的AlexNet验证了算法的有效性。结果表明,改进的AlexNet网络训练时间更快,综合识别率达到98.32%.     

融合深度学习和聚类分析的自适应图像聚类

针对卷积神经网络应用于图像分类任务时需要大量有标签数据的问题,提出一种融合卷积神经网络和聚类分析的无监督分类模型,将无监督算法引入深度学习,并将该模型应用到图像分类领域,来弥补现有分类方式的不足.首先对经典卷积神经网络AlexNet从网络结构和模型训练两个方面进行优化;然后利用改进后的自适应快速峰值聚类算法指导聚类过程...     

Modulation classification in the presence of adjacent channel interference using convolutional neural networks

This paper investigates a vital issue in wireless communication systems, which is the modulation classification. A proposed framework for modulation classification based on deep learning (DL) is presented in the presence of adjacent channel interference (ACI). This framework begins with the generation of constellation diagrams from the received data. These constellation diagrams are fed to convolutional neural networks (CNNs) for modulation classification. The objective of this process is to eliminate the manual feature extraction from the received data and make feature extraction process as a built‐in step with CNNs. Three types of CNNs are considered in this paper and compared for this objective. These types are AlexNet, VGG‐16, and VGG‐19. The proposed classifier is applied on Rayliegh and Rician fading channels.     

卷积神经网络金相组织自动识别

为了降低人工分辨金相组织图像类别的误差率,提高分辨效率,采用卷积神经网络模型对金相组织图像进行自动辨识。对制备金相样块所得铁素体与马氏体两种金相组织图像进行分析,提出符合金相组织图像分布特征的预处理方案。通过采用图像尺寸归一化、灰度值归一化以及高斯平滑处理等方法,对原始金相组织图像进行预处理,建立金相组织图像数据集。针对建立的铁素体和马氏体金相组织图像数据集,提出了适合金相组织图像辨识的改进模型,分别记为LeNet-MetStr模型、AlexNet-MetStr模型和VGGNet-MetStr模型。对3种改进卷积神经网络进行模型训练及分析,结果表明VGGNet-MetStr模型对2种金相组织图像自动辨识具有更高的准确度。     

一种新型的半导体SMA缺陷识别方法的研究

摘 要: 针对半导体器件在封装工艺中出现表面缺陷,及缺陷形态多样性和不可预测性而带来的模型适应性低等问题,提出了基于双向二维主成分分析和改进的卷积神经网络相结合的缺陷识别方法。首先为克服样本不均匀带来的识别精度低问题,对训练图像进行反射变换等操作构造虚拟样本,然后使用Bi-2DPCA对图像进行降维压缩,提取图像主要特征,再由改进的AlexNet网络进行缺陷识别分类,并提出正态随机采样层,将其加在AlexNet网络的卷积层后进行下采样,同时在全连接层中引入DropConnect来提高网络的泛化性能。实验表明,提出的算法较相关算法有较高的识别率,并在实际的SMA塑封图像数据上得到了验证,同时该算法具有较好的泛化性能。     

基于改进AlexNet卷积神经网络的手写体数字识别

为了提高手写体数字的识别率,在AlexNet网络模型的基础上进行改进,引入Inception-resnet模块替换模型中的Conv3和Conv4来提升模型的特征提取能力;使用批归一化处理（BN）方法加快网络的收敛速度,防止过拟合;减少卷积核的数量,提升网络的训练速度。在MNIST数据集上进行训练与测试,实验结果表明改进的网络模型具有较高的检测精度,达到了0.9966,证明了本算法的有效性。