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Sparse Seismic Data Reconstruction Based on a Convolutional Neural Network Algorithm
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作者 HOU Xinwei TONG Siyou +3 位作者 WANG Zhongcheng XU Xiugang PENG Yin WANG Kai 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第2期410-418,共9页
At present,the acquisition of seismic data is developing toward high-precision and high-density methods.However,complex natural environments and cultural factors in many exploration areas cause difficulties in achievi... At present,the acquisition of seismic data is developing toward high-precision and high-density methods.However,complex natural environments and cultural factors in many exploration areas cause difficulties in achieving uniform and intensive acquisition,which makes complete seismic data collection impossible.Therefore,data reconstruction is required in the processing link to ensure imaging accuracy.Deep learning,as a new field in rapid development,presents clear advantages in feature extraction and modeling.In this study,the convolutional neural network deep learning algorithm is applied to seismic data reconstruction.Based on the convolutional neural network algorithm and combined with the characteristics of seismic data acquisition,two training strategies of supervised and unsupervised learning are designed to reconstruct sparse acquisition seismic records.First,a supervised learning strategy is proposed for labeled data,wherein the complete seismic data are segmented as the input of the training set and are randomly sampled before each training,thereby increasing the number of samples and the richness of features.Second,an unsupervised learning strategy based on large samples is proposed for unlabeled data,and the rolling segmentation method is used to update(pseudo)labels and training parameters in the training process.Through the reconstruction test of simulated and actual data,the deep learning algorithm based on a convolutional neural network shows better reconstruction quality and higher accuracy than compressed sensing based on Curvelet transform. 展开更多
关键词 deep learning convolutional neural network seismic data reconstruction compressed sensing sparse collection supervised learning unsupervised learning
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Optimal Deep Dense Convolutional Neural Network Based Classification Model for COVID-19 Disease 被引量:1
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作者 A.Sheryl Oliver P.Suresh +2 位作者 A.Mohanarathinam Seifedine Kadry Orawit Thinnukool 《Computers, Materials & Continua》 SCIE EI 2022年第1期2031-2047,共17页
Early diagnosis and detection are important tasks in controlling the spread of COVID-19.A number of Deep Learning techniques has been established by researchers to detect the presence of COVID-19 using CT scan images ... Early diagnosis and detection are important tasks in controlling the spread of COVID-19.A number of Deep Learning techniques has been established by researchers to detect the presence of COVID-19 using CT scan images and X-rays.However,these methods suffer from biased results and inaccurate detection of the disease.So,the current research article developed Oppositional-based Chimp Optimization Algorithm and Deep Dense Convolutional Neural Network(OCOA-DDCNN)for COVID-19 prediction using CT images in IoT environment.The proposed methodology works on the basis of two stages such as pre-processing and prediction.Initially,CT scan images generated from prospective COVID-19 are collected from open-source system using IoT devices.The collected images are then preprocessed using Gaussian filter.Gaussian filter can be utilized in the removal of unwanted noise from the collected CT scan images.Afterwards,the preprocessed images are sent to prediction phase.In this phase,Deep Dense Convolutional Neural Network(DDCNN)is applied upon the pre-processed images.The proposed classifier is optimally designed with the consideration of Oppositional-basedChimp Optimization Algorithm(OCOA).This algorithm is utilized in the selection of optimal parameters for the proposed classifier.Finally,the proposed technique is used in the prediction of COVID-19 and classify the results as either COVID-19 or non-COVID-19.The projected method was implemented in MATLAB and the performances were evaluated through statistical measurements.The proposed method was contrasted with conventional techniques such as Convolutional Neural Network-Firefly Algorithm(CNN-FA),Emperor Penguin Optimization(CNN-EPO)respectively.The results established the supremacy of the proposed model. 展开更多
关键词 Deep learning deep dense convolutional neural network covid-19 CT images chimp optimization algorithm
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Anomaly-Based Intrusion DetectionModel Using Deep Learning for IoT Networks
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作者 Muaadh A.Alsoufi Maheyzah Md Siraj +4 位作者 Fuad A.Ghaleb Muna Al-Razgan Mahfoudh Saeed Al-Asaly Taha Alfakih Faisal Saeed 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第10期823-845,共23页
The rapid growth of Internet of Things(IoT)devices has brought numerous benefits to the interconnected world.However,the ubiquitous nature of IoT networks exposes them to various security threats,including anomaly int... The rapid growth of Internet of Things(IoT)devices has brought numerous benefits to the interconnected world.However,the ubiquitous nature of IoT networks exposes them to various security threats,including anomaly intrusion attacks.In addition,IoT devices generate a high volume of unstructured data.Traditional intrusion detection systems often struggle to cope with the unique characteristics of IoT networks,such as resource constraints and heterogeneous data sources.Given the unpredictable nature of network technologies and diverse intrusion methods,conventional machine-learning approaches seem to lack efficiency.Across numerous research domains,deep learning techniques have demonstrated their capability to precisely detect anomalies.This study designs and enhances a novel anomaly-based intrusion detection system(AIDS)for IoT networks.Firstly,a Sparse Autoencoder(SAE)is applied to reduce the high dimension and get a significant data representation by calculating the reconstructed error.Secondly,the Convolutional Neural Network(CNN)technique is employed to create a binary classification approach.The proposed SAE-CNN approach is validated using the Bot-IoT dataset.The proposed models exceed the performance of the existing deep learning approach in the literature with an accuracy of 99.9%,precision of 99.9%,recall of 100%,F1 of 99.9%,False Positive Rate(FPR)of 0.0003,and True Positive Rate(TPR)of 0.9992.In addition,alternative metrics,such as training and testing durations,indicated that SAE-CNN performs better. 展开更多
关键词 IOT anomaly intrusion detection deep learning sparse autoencoder convolutional neural network
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多尺度密集交互注意力残差真实图像去噪网络
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作者 郭业才 胡晓伟 +1 位作者 AMITAVE Saha 毛湘南 《图学学报》 北大核心 2025年第2期279-287,共9页
针对图像去噪特征提取不全面以及特征利用率低,导致生成图像不够清晰的问题,提出一种多尺度密集交互注意力残差去噪网络(MDIARN)。首先,通过多尺度非对称特征提取模块(MAFM)初步提取浅层信息特征,以确保图像特征的多样性;然后,多尺度级... 针对图像去噪特征提取不全面以及特征利用率低,导致生成图像不够清晰的问题,提出一种多尺度密集交互注意力残差去噪网络(MDIARN)。首先,通过多尺度非对称特征提取模块(MAFM)初步提取浅层信息特征,以确保图像特征的多样性;然后,多尺度级联模块(MSCM)利用多维密集交互残差单元(MDIU)对图像特征进行多维映射,并逐步级联以增强模型之间的信息传递和交互性,充分拟合训练数据;引入双路全局注意力模块(DGAM)对多级特征进行全局联合学习,获取更具有判别性的特征信息;跳跃连接促进结构之间的参数共享,使不同维度的特征充分融合,保证信息的完整性;最后,采用残差学习构建出清晰的去噪图像。结果表明,该算法在真实噪声数据集(DND和SIDD)上峰值信噪比分别为39.80 dB和39.62 dB,结构相似性分别为95.4%和95.8%,均优于主流去噪算法。此外,该算法在低光度场景下应用也能保留更多细节,从而显著提升图像质量。 展开更多
关键词 图像去噪 多尺度特征提取 多维密集交互 卷积神经网络 注意力
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基于稀疏注意力卷积ViT模型的锌浮选工况识别
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作者 苏越 唐朝晖 +4 位作者 谢永芳 高小亮 张虎 马炜烨 汤海玚 《工程科学学报》 EI 北大核心 2025年第2期328-338,共11页
准确识别锌浮选工况并用于指导锌浮选操作,可以提高浮选效率、优化选矿过程.目前浮选现场主要通过人工肉眼观察泡沫并依据经验判断工况,这种方法主观性强,难以客观准确地评价锌浮选工况.针对该问题,本文通过研究锌浮选泡沫视觉特征和浮... 准确识别锌浮选工况并用于指导锌浮选操作,可以提高浮选效率、优化选矿过程.目前浮选现场主要通过人工肉眼观察泡沫并依据经验判断工况,这种方法主观性强,难以客观准确地评价锌浮选工况.针对该问题,本文通过研究锌浮选泡沫视觉特征和浮选工况的密切联系,提出基于稀疏注意力卷积ViT模型的锌浮选工况识别方法.首先,所提模型融合了卷积神经网络(Convolutional neural networks,CNN)和视觉Transformer(Vision transformer,ViT)的结构和优点,同时感知泡沫局部空间信息和全局信息,完备表征泡沫图像.其次,模型引入稀疏的多头注意力机制,每个注意力头以不同的稀疏程度处理特征,从不同尺度下感知全局信息,同时引入注意力门控单元优化特征传递,最终实现锌浮选工况识别.实验结果表明,本文所提工况识别方法在锌浮选泡沫图像数据集上的准确率达到88.62%,解决了传统CNN和ViT模型不能充分利用泡沫图像全局信息,且无法自适应捕捉泡沫图像重要特征的问题,为浮选流程优化提供有力支持. 展开更多
关键词 工况识别 卷积神经网络 视觉Transformer 稀疏注意力 泡沫浮选
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基于多尺度注意力网络的密集人群计数
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作者 文帅 蒋勇 +2 位作者 杨丹 马金刚 杨闻宇 《计算机应用与软件》 北大核心 2025年第1期130-136,157,共8页
针对拥挤场景下的尺度变化导致人群计数任务中精度较低的问题,提出一种基于多尺度注意力网络(MANet)的密集人群计数模型。通过构建多列模型以捕获多尺度特征,促进尺度信息融合;使用双注意力模块获取上下文依赖关系,增强多尺度特征图的信... 针对拥挤场景下的尺度变化导致人群计数任务中精度较低的问题,提出一种基于多尺度注意力网络(MANet)的密集人群计数模型。通过构建多列模型以捕获多尺度特征,促进尺度信息融合;使用双注意力模块获取上下文依赖关系,增强多尺度特征图的信息;采用密集连接重用多尺度特征图,生成高质量的密度图,之后对密度图积分得到计数。此外,提出一种新的损失函数,直接使用点注释图进行训练,以减少由高斯滤波生成新的密度图而带来的额外的误差。在公开人群数据集ShanghaiTech Part A/B、UCF-CC-50、UCF-QNRF上的实验结果均达到了最优,表明该网络可以有效处理拥挤场景下的目标多尺度,并且生成高质量的密度图。 展开更多
关键词 密集人群计数 多尺度 卷积神经网络 注意力机制 密集连接 损失函数
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基于音频特征融合的振动筛故障诊断方法
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作者 李越 李敬兆 +2 位作者 何长林 王斌 李彪 《兰州工业学院学报》 2025年第1期60-67,共8页
为及时发现振动筛的故障,提出一种融合改进梅尔频率倒谱系数(MFCC)、密集卷积神经网络(Dense-CNN)和双向长短期记忆网络(BiLSTM)的振动筛故障诊断模型(Dense-CNN-BiLSTM)。首先,利用固有时间尺度分解(ITD)对振动筛音频信号进行时频分析... 为及时发现振动筛的故障,提出一种融合改进梅尔频率倒谱系数(MFCC)、密集卷积神经网络(Dense-CNN)和双向长短期记忆网络(BiLSTM)的振动筛故障诊断模型(Dense-CNN-BiLSTM)。首先,利用固有时间尺度分解(ITD)对振动筛音频信号进行时频分析,提取其固有旋转分量(PRC);其次,提取由独立成分分析(ICA)改进的13维MFCC特征参数,并将特征参数输入Dense-CNN-BiLSTM模型,实现振动筛的故障诊断。结果表明:改进的MFCC特征参数能表示振动筛不同运行状态的音频信号特征,验证了基于音频特征融合实现振动筛故障诊断的可行性。 展开更多
关键词 振动筛 梅尔频率倒谱系数 密集卷积神经网络 双向长短期记忆网络
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面向不间断供电(UPS)系统的电能质量分析技术
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作者 邓卜侨 谢岫峰 +2 位作者 纪明阳 艾青 王康 《电子设计工程》 2025年第1期12-16,共5页
针对现行UPS电能质量检测过程存在的准确率低、实时性差且成本高的缺点,文中基于VMD-SAE-1DCNN模型提出了一种UPS电能质量检测与识别算法。对于电能信号非线性与非平稳的特点,使用变分模态算法对原信号进行分解,从而得到本征模态信号。... 针对现行UPS电能质量检测过程存在的准确率低、实时性差且成本高的缺点,文中基于VMD-SAE-1DCNN模型提出了一种UPS电能质量检测与识别算法。对于电能信号非线性与非平稳的特点,使用变分模态算法对原信号进行分解,从而得到本征模态信号。同时,采用稀疏自编码器对本征模态信号进行特征提取,通过建立多层一维卷积神经网络模型对特征进行训练,提升了运算效率。实验测试结果表明,所提算法的迭代次数与运行时间在对比算法中均为最优,分类准确率可达97%以上,充分证明了改进算法的有效性。 展开更多
关键词 UPS 变分模态算法 稀疏自编码器 卷积神经网络 电能质量分析
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Single Image Rain Removal Using Image Decomposition and a Dense Network 被引量:2
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作者 Qiusheng Lian Wenfeng Yan +1 位作者 Xiaohua Zhang Shuzhen Chen 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2019年第6期1428-1437,共10页
Removing rain from a single image is a challenging task due to the absence of temporal information. Considering that a rainy image can be decomposed into the low-frequency(LF) and high-frequency(HF) components, where ... Removing rain from a single image is a challenging task due to the absence of temporal information. Considering that a rainy image can be decomposed into the low-frequency(LF) and high-frequency(HF) components, where the coarse scale information is retained in the LF component and the rain streaks and texture correspond to the HF component, we propose a single image rain removal algorithm using image decomposition and a dense network. We design two task-driven sub-networks to estimate the LF and non-rain HF components of a rainy image. The high-frequency estimation sub-network employs a densely connected network structure, while the low-frequency sub-network uses a simple convolutional neural network(CNN).We add total variation(TV) regularization and LF-channel fidelity terms to the loss function to optimize the two subnetworks jointly. The method then obtains de-rained output by combining the estimated LF and non-rain HF components.Extensive experiments on synthetic and real-world rainy images demonstrate that our method removes rain streaks while preserving non-rain details, and achieves superior de-raining performance both perceptually and quantitatively. 展开更多
关键词 convolutional neural network(CNN) DENSE network image decomposition RAIN removal TOTAL variation(TV)
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3D brain glioma segmentation in MRI through integrating multiple densely connected 2D convolutional neural networks 被引量:5
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作者 Xiaobing ZHANG Yin HU +2 位作者 Wen CHEN Gang HUANG Shengdong NIE 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2021年第6期462-475,共14页
To overcome the computational burden of processing three-dimensional(3 D)medical scans and the lack of spatial information in two-dimensional(2 D)medical scans,a novel segmentation method was proposed that integrates ... To overcome the computational burden of processing three-dimensional(3 D)medical scans and the lack of spatial information in two-dimensional(2 D)medical scans,a novel segmentation method was proposed that integrates the segmentation results of three densely connected 2 D convolutional neural networks(2 D-CNNs).In order to combine the lowlevel features and high-level features,we added densely connected blocks in the network structure design so that the low-level features will not be missed as the network layer increases during the learning process.Further,in order to resolve the problems of the blurred boundary of the glioma edema area,we superimposed and fused the T2-weighted fluid-attenuated inversion recovery(FLAIR)modal image and the T2-weighted(T2)modal image to enhance the edema section.For the loss function of network training,we improved the cross-entropy loss function to effectively avoid network over-fitting.On the Multimodal Brain Tumor Image Segmentation Challenge(BraTS)datasets,our method achieves dice similarity coefficient values of 0.84,0.82,and 0.83 on the BraTS2018 training;0.82,0.85,and 0.83 on the BraTS2018 validation;and 0.81,0.78,and 0.83 on the BraTS2013 testing in terms of whole tumors,tumor cores,and enhancing cores,respectively.Experimental results showed that the proposed method achieved promising accuracy and fast processing,demonstrating good potential for clinical medicine. 展开更多
关键词 GLIOMA Magnetic resonance imaging(MRI) SEGMENTATION Dense block 2D convolutional neural networks(2D-CNNs)
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Multi-Layer Deep Sparse Representation for Biological Slice Image Inpainting
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作者 Haitao Hu Hongmei Ma Shuli Mei 《Computers, Materials & Continua》 SCIE EI 2023年第9期3813-3832,共20页
Biological slices are an effective tool for studying the physiological structure and evolutionmechanism of biological systems.However,due to the complexity of preparation technology and the presence of many uncontroll... Biological slices are an effective tool for studying the physiological structure and evolutionmechanism of biological systems.However,due to the complexity of preparation technology and the presence of many uncontrollable factors during the preparation processing,leads to problems such as difficulty in preparing slice images and breakage of slice images.Therefore,we proposed a biological slice image small-scale corruption inpainting algorithm with interpretability based on multi-layer deep sparse representation,achieving the high-fidelity reconstruction of slice images.We further discussed the relationship between deep convolutional neural networks and sparse representation,ensuring the high-fidelity characteristic of the algorithm first.A novel deep wavelet dictionary is proposed that can better obtain image prior and possess learnable feature.And multi-layer deep sparse representation is used to implement dictionary learning,acquiring better signal expression.Compared with methods such as NLABH,Shearlet,Partial Differential Equation(PDE),K-Singular Value Decomposition(K-SVD),Convolutional Sparse Coding,and Deep Image Prior,the proposed algorithm has better subjective reconstruction and objective evaluation with small-scale image data,which realized high-fidelity inpainting,under the condition of small-scale image data.And theOn2-level time complexitymakes the proposed algorithm practical.The proposed algorithm can be effectively extended to other cross-sectional image inpainting problems,such as magnetic resonance images,and computed tomography images. 展开更多
关键词 Deep sparse representation image inpainting convolutional sparse modelling deep neural network
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基于卷积特征提取及深度降噪网络的大规模MIMO系统信号检测 被引量:3
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作者 申滨 涂媛媛 +1 位作者 阳建 金龙康 《信号处理》 CSCD 北大核心 2024年第6期1030-1040,共11页
传统多输入多输出(Multiple-Input Multiple-Output,MIMO)信号检测算法受到天线数量和收发天线比例的限制,一般仅适用于少量天线、收发天线比例较低的情况。本文提出一种基于深度学习(Deep Learning,DL)的稀疏连接卷积降噪网络模型,用... 传统多输入多输出(Multiple-Input Multiple-Output,MIMO)信号检测算法受到天线数量和收发天线比例的限制,一般仅适用于少量天线、收发天线比例较低的情况。本文提出一种基于深度学习(Deep Learning,DL)的稀疏连接卷积降噪网络模型,用于大规模MIMO系统上行链路信号检测。首先,通过简化经典的检测网络(Detection Network,DetNet),改进ScNet(Sparsely Connected Neural Network)检测算法,引入卷积神经网络(Convolutional NeuralNetworks,CNN)对三通道输入数据提取特征以减少训练参数,提出一种SConv(SparselyConnected Convolutional Neural Network)检测算法。与DetNet算法相比,该算法可同时降低计算复杂度和提高检测精度。在此基础上,进一步基于CNN构建信号降噪模块,并嵌入SConv网络,提出一种卷积神经降噪(Sparsely Connected Convolutional Denoising,SConv-D)网络辅助的大规模MIMO检测算法。此算法检测过程分为两级,第一级由SConv算法提供初始估计值,再将初始估计值作为降噪过程的输入,并由此构成算法第二级。实验结果表明,本文提出的SConv-D算法适用于QPSK、4QAM及16QAM等多种信号调制模式,在高阶调制模式下获得的性能增益尤为明显。此外,该算法能够适应各种比例的收发天线及数量规模的系统配置,尤其是在收发天线数量相等的情况下亦能获得更优的性能。本文算法还克服了MMNet在高阶调制情况下的性能平台效应,在16QAM调制、收发天线数量相等的情况下,SConv-D在10^(-2)误比特率上能获得接近2 dB的性能增益。 展开更多
关键词 大规模MIMO 深度学习 稀疏连接 卷积神经网络 降噪
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基于残差密集块的激光遥感图像中目标检测方法 被引量:1
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作者 李雪 刘悦 王青正 《激光杂志》 CAS 北大核心 2024年第8期98-102,共5页
为了提高对目标检测的效果,提出基于残差密集块的激光遥感图像中目标检测方法。首先,设计基于残差密集块的卷积神经网络,在设计ReLU激活函数并完成网络训练后,基于含噪激光遥感图像的初步特征提取结果,利用单个卷积展开卷积映射处理,抽... 为了提高对目标检测的效果,提出基于残差密集块的激光遥感图像中目标检测方法。首先,设计基于残差密集块的卷积神经网络,在设计ReLU激活函数并完成网络训练后,基于含噪激光遥感图像的初步特征提取结果,利用单个卷积展开卷积映射处理,抽取出潜在干净图像。然后,通过聚类处理的方式,得到激光遥感图像中车辆目标的显著图,再利用大律法,通过建立的特征比例关系的方式检测出其中的目标信息。实验结果表明,应用该方法有效滤除激光遥感图像中的噪声,并精准检测出激光遥感图像中的车辆目标。相比于3种传统方法,该方法检测结果均值误差的最小值仅为0.0156,说明该方法有效实现了设计预期。 展开更多
关键词 激光遥感图像 残差密集块 卷积神经网络 聚类算法 大律法 目标检测 去噪处理
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融合稀疏八叉树与卷积神经网络的汽车风阻系数预测 被引量:1
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作者 王刚 张瑞昊 +2 位作者 刘学龙 袁海东 韩旭 《计算力学学报》 CAS CSCD 北大核心 2024年第1期58-65,共8页
针对汽车风阻系数预测研究中参数化方法难以准确表征汽车外造型的难题,提出融合稀疏八叉树与卷积神经网络的汽车风阻系数预测方法。将汽车外造型按照八叉树结构离散,使用平均法向量对离散的复杂曲面进行简化,利用卷积神经网络对八叉树... 针对汽车风阻系数预测研究中参数化方法难以准确表征汽车外造型的难题,提出融合稀疏八叉树与卷积神经网络的汽车风阻系数预测方法。将汽车外造型按照八叉树结构离散,使用平均法向量对离散的复杂曲面进行简化,利用卷积神经网络对八叉树形式的汽车外造型进行特征提取,进而对汽车风阻系数进行快速预测。通过改变卷积层数与全连接层数,研究了不同卷积神经网络结构对风阻系数预测精度的影响。与参数化方法相比,本文提出的外造型表示方法能更好地描述模型细节,构建的卷积神经网络结构对风阻系数预测的最小相对误差为1.453%,且计算速度是CFD仿真的1620倍,具有较高的精度及计算效率。 展开更多
关键词 风阻系数 深度学习 稀疏八叉树 卷积神经网络 汽车
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多任务联合学习的图卷积神经网络推荐 被引量:1
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作者 王永贵 邹赫宇 《计算机工程与应用》 CSCD 北大核心 2024年第4期306-314,共9页
基于图神经网络的协同过滤推荐可以更有效地挖掘用户项目之间的交互信息,但其性能依然受到数据稀疏和表征学习质量不高问题的影响,因此提出一种多任务联合学习的图卷积神经网络推荐(multi-task joint learning for graph convolutional ... 基于图神经网络的协同过滤推荐可以更有效地挖掘用户项目之间的交互信息,但其性能依然受到数据稀疏和表征学习质量不高问题的影响,因此提出一种多任务联合学习的图卷积神经网络推荐(multi-task joint learning for graph convolutional neural network recommendations,MTJL-GCN)模型。利用图神经网络在用户-项目交互图上所聚集到的同质结构信息与初始嵌入信息形成结构邻居关系,设计节点邻居关系的对比学习辅助任务来缓解数据稀疏问题;向节点的原始表征添加随机的统一噪声进行表征级数据增强,构建节点表征关系的对比学习辅助任务,并提出直接优化对齐性和均匀性两个属性的学习目标来提高表征学习质量;将图协同过滤推荐任务与对比学习辅助任务和直接优化学习目标进行联合训练,从而提升推荐性能。在Amazon-books和Yelp2018两个公开数据集上进行实验,该模型在Recall@k和NDCG@k两个推荐性能指标上的表现均优于基线模型,证明了MTJL-GCN模型的有效性。 展开更多
关键词 推荐算法 图卷积神经网络 对比学习 表征学习 数据稀疏 协同过滤
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Performance Evaluation of Super-Resolution Methods Using Deep-Learning and Sparse-Coding for Improving the Image Quality of Magnified Images in Chest Radiographs
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作者 Kensuke Umehara Junko Ota +4 位作者 Naoki Ishimaru Shunsuke Ohno Kentaro Okamoto Takanori Suzuki Takayuki Ishida 《Open Journal of Medical Imaging》 2017年第3期100-111,共12页
Purpose: To detect small diagnostic signals such as lung nodules in chest radiographs, radiologists magnify a region-of-interest using linear interpolation methods. However, such methods tend to generate over-smoothed... Purpose: To detect small diagnostic signals such as lung nodules in chest radiographs, radiologists magnify a region-of-interest using linear interpolation methods. However, such methods tend to generate over-smoothed images with artifacts that can make interpretation difficult. The purpose of this study was to investigate the effectiveness of super-resolution methods for improving the image quality of magnified chest radiographs. Materials and Methods: A total of 247 chest X-rays were sampled from the JSRT database, then divided into 93 training cases with non-nodules and 154 test cases with lung nodules. We first trained two types of super-resolution methods, sparse-coding super-resolution (ScSR) and super-resolution convolutional neural network (SRCNN). With the trained super-resolution methods, the high-resolution image was then reconstructed using the super-resolution methods from a low-resolution image that was down-sampled from the original test image. We compared the image quality of the super-resolution methods and the linear interpolations (nearest neighbor and bilinear interpolations). For quantitative evaluation, we measured two image quality metrics: peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). For comparative evaluation of the super-resolution methods, we measured the computation time per image. Results: The PSNRs and SSIMs for the ScSR and the SRCNN schemes were significantly higher than those of the linear interpolation methods (p p p Conclusion: Super-resolution methods provide significantly better image quality than linear interpolation methods for magnified chest radiograph images. Of the two tested schemes, the SRCNN scheme processed the images fastest;thus, SRCNN could be clinically superior for processing radiographs in terms of both image quality and processing speed. 展开更多
关键词 Deep LEARNING SUPER-RESOLUTION SUPER-RESOLUTION convolutional neural network (SRCNN) sparse-Coding SUPER-RESOLUTION (ScSR) CHEST X-Ray
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基于注意力机制和软匹配的多标签遥感图像检索方法 被引量:1
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作者 张永梅 徐敏 李小冬 《计算机应用与软件》 北大核心 2024年第6期181-185,199,共6页
针对卷积神经网络对于多标签遥感图像特征提取能力弱、不能准确反映遥感图像多标签复杂性的问题,提出基于注意力机制和软匹配的多标签遥感图像检索方法。在特征提取阶段,以密集卷积神经网络模型为基础,在每个密集块(Dense Block)后添加C... 针对卷积神经网络对于多标签遥感图像特征提取能力弱、不能准确反映遥感图像多标签复杂性的问题,提出基于注意力机制和软匹配的多标签遥感图像检索方法。在特征提取阶段,以密集卷积神经网络模型为基础,在每个密集块(Dense Block)后添加CBAM(Convolutional Block Attention Module)层,实现对多标签图像区域特征提取。在模型训练时,利用区分硬匹配与软匹配的联合损失函数,学习图像的哈希编码表示。通过评估遥感图像哈希编码间的汉明距离,实现相似图像的检索。实验结果表明,所提方法在数据集NUS-WIDE和多标签遥感图像数据集DLRSD上与其他基于全局特征的深度哈希方法相比,明显提升了检索准确率。 展开更多
关键词 遥感图像检索 密集卷积神经网络 深度哈希 多标签 软匹配
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AR-MED共振特征增强的风电齿轮箱故障诊断
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作者 孙抗 史晓玉 +1 位作者 赵来军 杨明 《组合机床与自动化加工技术》 北大核心 2024年第8期163-167,174,共6页
针对风电齿轮箱故障时脉冲成分往往淹没在其他频率分量中,早期故障特征难以有效提取的问题,提出一种自回归最小熵解卷积(AR-MED)共振特征增强的风电齿轮箱故障诊断方法,并结合一维卷积神经网络(1DCNN),实现齿轮箱高精度故障诊断。首先,... 针对风电齿轮箱故障时脉冲成分往往淹没在其他频率分量中,早期故障特征难以有效提取的问题,提出一种自回归最小熵解卷积(AR-MED)共振特征增强的风电齿轮箱故障诊断方法,并结合一维卷积神经网络(1DCNN),实现齿轮箱高精度故障诊断。首先,使用共振稀疏分解算法(RSSD)将振动信号分解成含有噪声和谐波成分的高共振分量和含有故障冲击成分的低共振分量;其次,对低共振分量使用自回归最小熵解卷积运算,增强低共振分量中微弱的周期性冲击成分;最后,构建自回归最小熵解卷积共振特征增强的1DCNN模型,将分解得到的谐波分量和周期性冲击分量进行特征融合以及有针对的训练和分类。实验结果表明,与现有故障诊断模型相比,所提方法在提取风电齿轮箱的故障特征信息以及提高故障诊断精度方面具有有效性和优越性。 展开更多
关键词 共振稀疏分解 自回归最小熵解卷积 特征增强 一维卷积神经网络 风电齿轮箱
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基于多特征优化的PolSAR数据农作物精细分类方法
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作者 郭交 王鹤颖 +2 位作者 项诗雨 连嘉茜 王辉 《农业机械学报》 EI CAS CSCD 北大核心 2024年第9期275-285,共11页
农作物精细分类在农业资源调查、农作物种植结构监管等诸多领域具有重要意义。极化合成孔径雷达(Polarimetric synthetic aperture radar,PolSAR)能够有效探测伪装和穿透掩盖物,提取多种散射特征信息,获取覆盖农作物生长关键物候阶段的... 农作物精细分类在农业资源调查、农作物种植结构监管等诸多领域具有重要意义。极化合成孔径雷达(Polarimetric synthetic aperture radar,PolSAR)能够有效探测伪装和穿透掩盖物,提取多种散射特征信息,获取覆盖农作物生长关键物候阶段的连续时序信息,有效提升表达作物遥感特征的丰富度,在农作物分类中独具优势。但多时相和多特征的引入必然导致模型运算量剧增,不利于工程应用。针对上述问题,本文提出了一种基于多特征优化的PolSAR数据农作物精细分类方法,首先对PolSAR数据进行多种极化目标分解及参数提取以获得多个散射特征;然后使用基于栈式稀疏自编码网络和ReliefF优选的方法进行特征增强与优化,获取最优特征集;最后构建具有2个分支结构的卷积神经网络,融合不同卷积深度输出的特征,完成农作物的高精度分类。通过对单时相数据的特征分析、单时相数据初步分类实验和多时相数据不同特征集结合分类器的对比实验,证明本文所提方法能够在低维特征输入的前提下,最大程度提取不同作物之间的差异性特征,准确高效地实现对农作物的精细分类,最高分类精度和Kappa系数分别达到97.69%和97.24%。 展开更多
关键词 农作物分类 POLSAR 栈式稀疏自编码网络 RELIEFF 卷积神经网络
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融合选择性稀疏采样的细粒度图像分类
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作者 孙红 陈玉娟 宋冬豪 《小型微型计算机系统》 CSCD 北大核心 2024年第6期1460-1465,共6页
常用的细粒度分类方法通过提取局部信息学习细粒度特征,容易忽视周围环境因素影响问题,造成分类精度下降.针对这一问题提出了一个简单有效的框架,称为选择性稀疏采样.通过类峰值响应产生稀疏注意定位有信息的对象部分,根据图像内容选择... 常用的细粒度分类方法通过提取局部信息学习细粒度特征,容易忽视周围环境因素影响问题,造成分类精度下降.针对这一问题提出了一个简单有效的框架,称为选择性稀疏采样.通过类峰值响应产生稀疏注意定位有信息的对象部分,根据图像内容选择动态数量的稀疏注意,生成判别性和补充性两个分支进行视觉表示,使得特征部分和全局信息相辅相成.对于容易产生混淆的部分,引入了一个“梯度增强”损失,只关注每个样本的混淆类,为补充性分支提供更多的细节特征.通过实验结果表明,该方法在常用数据集的基准测试中分别达到了88.6%,92.8%和94.8%的精确度,验证了该方法的有效性. 展开更多
关键词 细粒度图像分类 选择稀疏采样 类峰值响应 梯度增强 卷积神经网络
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