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Weighted Forwarding in Graph Convolution Networks for Recommendation Information Systems
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作者 Sang-min Lee Namgi Kim 《Computers, Materials & Continua》 SCIE EI 2024年第2期1897-1914,共18页
Recommendation Information Systems(RIS)are pivotal in helping users in swiftly locating desired content from the vast amount of information available on the Internet.Graph Convolution Network(GCN)algorithms have been ... Recommendation Information Systems(RIS)are pivotal in helping users in swiftly locating desired content from the vast amount of information available on the Internet.Graph Convolution Network(GCN)algorithms have been employed to implement the RIS efficiently.However,the GCN algorithm faces limitations in terms of performance enhancement owing to the due to the embedding value-vanishing problem that occurs during the learning process.To address this issue,we propose a Weighted Forwarding method using the GCN(WF-GCN)algorithm.The proposed method involves multiplying the embedding results with different weights for each hop layer during graph learning.By applying the WF-GCN algorithm,which adjusts weights for each hop layer before forwarding to the next,nodes with many neighbors achieve higher embedding values.This approach facilitates the learning of more hop layers within the GCN framework.The efficacy of the WF-GCN was demonstrated through its application to various datasets.In the MovieLens dataset,the implementation of WF-GCN in LightGCN resulted in significant performance improvements,with recall and NDCG increasing by up to+163.64%and+132.04%,respectively.Similarly,in the Last.FM dataset,LightGCN using WF-GCN enhanced with WF-GCN showed substantial improvements,with the recall and NDCG metrics rising by up to+174.40%and+169.95%,respectively.Furthermore,the application of WF-GCN to Self-supervised Graph Learning(SGL)and Simple Graph Contrastive Learning(SimGCL)also demonstrated notable enhancements in both recall and NDCG across these datasets. 展开更多
关键词 Deep learning graph neural network graph convolution network graph convolution network model learning method recommender information systems
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Nonparametric Statistical Feature Scaling Based Quadratic Regressive Convolution Deep Neural Network for Software Fault Prediction
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作者 Sureka Sivavelu Venkatesh Palanisamy 《Computers, Materials & Continua》 SCIE EI 2024年第3期3469-3487,共19页
The development of defect prediction plays a significant role in improving software quality. Such predictions are used to identify defective modules before the testing and to minimize the time and cost. The software w... The development of defect prediction plays a significant role in improving software quality. Such predictions are used to identify defective modules before the testing and to minimize the time and cost. The software with defects negatively impacts operational costs and finally affects customer satisfaction. Numerous approaches exist to predict software defects. However, the timely and accurate software bugs are the major challenging issues. To improve the timely and accurate software defect prediction, a novel technique called Nonparametric Statistical feature scaled QuAdratic regressive convolution Deep nEural Network (SQADEN) is introduced. The proposed SQADEN technique mainly includes two major processes namely metric or feature selection and classification. First, the SQADEN uses the nonparametric statistical Torgerson–Gower scaling technique for identifying the relevant software metrics by measuring the similarity using the dice coefficient. The feature selection process is used to minimize the time complexity of software fault prediction. With the selected metrics, software fault perdition with the help of the Quadratic Censored regressive convolution deep neural network-based classification. The deep learning classifier analyzes the training and testing samples using the contingency correlation coefficient. The softstep activation function is used to provide the final fault prediction results. To minimize the error, the Nelder–Mead method is applied to solve non-linear least-squares problems. Finally, accurate classification results with a minimum error are obtained at the output layer. Experimental evaluation is carried out with different quantitative metrics such as accuracy, precision, recall, F-measure, and time complexity. The analyzed results demonstrate the superior performance of our proposed SQADEN technique with maximum accuracy, sensitivity and specificity by 3%, 3%, 2% and 3% and minimum time and space by 13% and 15% when compared with the two state-of-the-art methods. 展开更多
关键词 Software defect prediction feature selection nonparametric statistical Torgerson-Gower scaling technique quadratic censored regressive convolution deep neural network softstep activation function nelder-mead method
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Piecewise linear recursive convolution FDTD method for magnetized plasmas 被引量:4
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作者 Liu Song Zhong Shuangying Liu Shaobin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第2期290-295,共6页
The piecewise linear recursive convolution (PLRC) finite-different time-domain (FDTD) method greatly improves accuracy over the original recursive convolution (RC) FDTD approach but retains its speed and efficie... The piecewise linear recursive convolution (PLRC) finite-different time-domain (FDTD) method greatly improves accuracy over the original recursive convolution (RC) FDTD approach but retains its speed and efficiency advantages. A PLRC-FDTD formulation for magnetized plasma which incorporates both anisotropy and frequency dispersion at the same time is presented, enabled the transient analysis of magnetized plasma media. The technique is illustrated by numerical simulations the reflection and transmission coefficients through a magnetized plasma layer. The results show that the PLRC-FDTD method has significantly improved the accuracy over the original RC method. 展开更多
关键词 electromagnetic wave FDTD methods piecewise linear recursive convolution magnetized plasma.
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Sampling Methods for Efficient Training of Graph Convolutional Networks:A Survey 被引量:3
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作者 Xin Liu Mingyu Yan +3 位作者 Lei Deng Guoqi Li Xiaochun Ye Dongrui Fan 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2022年第2期205-234,共30页
Graph convolutional networks(GCNs)have received significant attention from various research fields due to the excellent performance in learning graph representations.Although GCN performs well compared with other meth... Graph convolutional networks(GCNs)have received significant attention from various research fields due to the excellent performance in learning graph representations.Although GCN performs well compared with other methods,it still faces challenges.Training a GCN model for large-scale graphs in a conventional way requires high computation and storage costs.Therefore,motivated by an urgent need in terms of efficiency and scalability in training GCN,sampling methods have been proposed and achieved a significant effect.In this paper,we categorize sampling methods based on the sampling mechanisms and provide a comprehensive survey of sampling methods for efficient training of GCN.To highlight the characteristics and differences of sampling methods,we present a detailed comparison within each category and further give an overall comparative analysis for the sampling methods in all categories.Finally,we discuss some challenges and future research directions of the sampling methods. 展开更多
关键词 Efficient training graph convolutional networks(GCNs) graph neural networks(GNNs) sampling method
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A Revised Piecewise Linear Recursive Convolution FDTD Method for Magnetized Plasmas 被引量:1
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作者 刘崧 钟双英 刘少斌 《Plasma Science and Technology》 SCIE EI CAS CSCD 2005年第6期3122-3126,共5页
The piecewise linear recursive convolution (PLRC) finite-different time-domain (FDTD) method improves accuracy over the original recursive convolution (RC) FDTD approach and current density convolution (JEC) b... The piecewise linear recursive convolution (PLRC) finite-different time-domain (FDTD) method improves accuracy over the original recursive convolution (RC) FDTD approach and current density convolution (JEC) but retains their advantages in speed and efficiency. This paper describes a revised piecewise linear recursive convolution PLRC-FDTD formulation for magnetized plasma which incorporates both anisotropy and frequency dispersion at the same time, enabling the transient analysis of magnetized plasma media. The technique is illustrated by numerical simulations of the reflection and transmission coefficients through a magnetized plasma layer. The results show that the revised PLRC-FDTD method has improved the accuracy over the original RC FDTD method and JEC FDTD method. 展开更多
关键词 Electromagnetic wave finite-different time-domain (FDTD) methods piecewise linear recursive convolution magnetized plasma
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Discrete Singular Convolution Method for Numerical Solutions of Fifth Order Korteweg-De Vries Equations 被引量:2
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作者 Edson Pindza Eben Maré 《Journal of Applied Mathematics and Physics》 2013年第7期5-15,共11页
A new computational method for solving the fifth order Korteweg-de Vries (fKdV) equation is proposed. The nonlinear partial differential equation is discretized in space using the discrete singular convolution (DSC) s... A new computational method for solving the fifth order Korteweg-de Vries (fKdV) equation is proposed. The nonlinear partial differential equation is discretized in space using the discrete singular convolution (DSC) scheme and an exponential time integration scheme combined with the best rational approximations based on the Carathéodory-Fejér procedure for time discretization. We check several numerical results of our approach against available analytical solutions. In addition, we computed the conservation laws of the fKdV equation. We find that the DSC approach is a very accurate, efficient and reliable method for solving nonlinear partial differential equations. 展开更多
关键词 FIFTH Order KORTEWEG-DE Vries Equations Discrete Singular convolution Exponential Time Discretization method Soliton Solutions Conservation LAWS
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Hyperspectral Image Sharpening Based on Deep Convolutional Neural Network and Spatial-Spectral Spread Transform Models
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作者 陆小辰 刘晓慧 +2 位作者 杨德政 赵萍 阳云龙 《Journal of Donghua University(English Edition)》 CAS 2023年第1期88-95,共8页
In order to improve the spatial resolution of hyperspectral(HS)image and minimize the spectral distortion,an HS and multispectral(MS)image fusion approach based on convolutional neural network(CNN)is proposed.The prop... In order to improve the spatial resolution of hyperspectral(HS)image and minimize the spectral distortion,an HS and multispectral(MS)image fusion approach based on convolutional neural network(CNN)is proposed.The proposed approach incorporates the linear spectral mixture model and spatial-spectral spread transform model into the learning phase of network,aiming to fully exploit the spatial-spectral information of HS and MS images,and improve the spectral fidelity of fusion images.Experiments on two real remote sensing data under different resolutions demonstrate that compared with some state-of-the-art HS and MS image fusion methods,the proposed approach achieves superior spectral fidelities and lower fusion errors. 展开更多
关键词 convolutional neural network(CNN) hyperspectral image image fusion multispectral image unmixing method
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Human and Machine Vision Based Indian Race Classification Using Modified-Convolutional Neural Network
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作者 Vani A.Hiremani Kishore Kumar Senapati 《Computer Systems Science & Engineering》 SCIE EI 2023年第3期2603-2618,共16页
The inter-class face classification problem is more reasonable than the intra-class classification problem.To address this issue,we have carried out empirical research on classifying Indian people to their geographica... The inter-class face classification problem is more reasonable than the intra-class classification problem.To address this issue,we have carried out empirical research on classifying Indian people to their geographical regions.This work aimed to construct a computational classification model for classifying Indian regional face images acquired from south and east regions of India,referring to human vision.We have created an Automated Human Intelligence System(AHIS)to evaluate human visual capabilities.Analysis of AHIS response showed that face shape is a discriminative feature among the other facial features.We have developed a modified convolutional neural network to characterize the human vision response to improve face classification accuracy.The proposed model achieved mean F1 and Matthew Correlation Coefficient(MCC)of 0.92 and 0.84,respectively,on the validation set,outperforming the traditional Convolutional Neural Network(CNN).The CNN-Contoured Face(CNN-FC)model is developed to train contoured face images to investigate the influence of face shape.Finally,to cross-validate the accuracy of these models,the traditional CNN model is trained on the same dataset.With an accuracy of 92.98%,the Modified-CNN(M-CNN)model has demonstrated that the proposed method could facilitate the tangible impact in intra-classification problems.A novel Indian regional face dataset is created for supporting this supervised classification work,and it will be available to the research community. 展开更多
关键词 Data collection and preparation human vision analysis machine vision canny edge approximation method color local binary patterns convolutional neural network
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Face Recognition across Time Lapse Using Convolutional Neural Networks 被引量:3
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作者 Hachim El Khiyari Harry Wechsler 《Journal of Information Security》 2016年第3期141-151,共11页
Time lapse, characteristic of aging, is a complex process that affects the reliability and security of biometric face recognition systems. This paper reports the novel use and effectiveness of deep learning, in genera... Time lapse, characteristic of aging, is a complex process that affects the reliability and security of biometric face recognition systems. This paper reports the novel use and effectiveness of deep learning, in general, and convolutional neural networks (CNN), in particular, for automatic rather than hand-crafted feature extraction for robust face recognition across time lapse. A CNN architecture using the VGG-Face deep (neural network) learning is found to produce highly discriminative and interoperable features that are robust to aging variations even across a mix of biometric datasets. The features extracted show high inter-class and low intra-class variability leading to low generalization errors on aging datasets using ensembles of subspace discriminant classifiers. The classification results for the all-encompassing authentication methods proposed on the challenging FG-NET and MORPH datasets are competitive with state-of-the-art methods including commercial face recognition engines and are richer in functionality and interoperability than existing methods as it handles mixed biometric datasets, e.g., FG-NET and MORPH. 展开更多
关键词 Aging AUTHENTICATION BIOMETRICS convolutional Neural Networks (CNN) Deep Learning Ensemble methods Face Recognition INTEROPERABILITY Security
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Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples 被引量:8
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作者 Yuan CAI Clarence W.DE SILVA +2 位作者 Bing LI Liqun WANG Ziwen WANG 《Instrumentation》 2019年第4期59-71,共13页
This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,and roundness of an apple.The developed machine learning me... This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,and roundness of an apple.The developed machine learning method uses the ability of learning representative features by means of a convolutional neural network(CNN),to determine suitable features of apples for the grading process.This information is fed into a one-to-one classifier that uses a support vector machine(SVM),instead of the softmax output layer of the CNN.In this manner,Yantai apples with similar shapes and low discrimination are graded using four different approaches.The fusion model using both CNN and SVM classifiers is much more accurate than the simple k-nearest neighbor(KNN),SVM,and CNN model when used separately for grading,and the learning ability and the generalization ability of the model is correspondingly increased by the combined method.Grading tests are carried out using the automated grading device that is developed in the present work.It is verified that the actual effect of apple grading using the combined CNN-SVM model is fast and accurate,which greatly reduces the manpower and labor costs of manual grading,and has important commercial prospects. 展开更多
关键词 Apple Grading k-nearest Neighbour method convolutional Neural Network Support Vector Machine Machine Learning
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Borehole-GPR numerical simulation of full wave field based on convolutional perfect matched layer boundary 被引量:7
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作者 朱自强 彭凌星 +1 位作者 鲁光银 密士文 《Journal of Central South University》 SCIE EI CAS 2013年第3期764-769,共6页
The absorbing boundary is the key in numerical simulation of borehole radar.Perfect match layer(PML) was chosen as the absorbing boundary in numerical simulation of GPR.But CPML(convolutional perfect match layer) appr... The absorbing boundary is the key in numerical simulation of borehole radar.Perfect match layer(PML) was chosen as the absorbing boundary in numerical simulation of GPR.But CPML(convolutional perfect match layer) approach that we have chosen has the advantage of being media independent.Beginning with the Maxwell equations in a two-dimensional structure,numerical formulas of finite-difference time-domain(FDTD) method with CPML boundary condition for transverse electric(TE) or transverse magnetic(TM) wave are presented in details.Also,there are three models for borehole-GPR simulation.By analyzing the simulation results,the features of targets in GPR are obtained,which can provide a better interpretation of real radar data.The results show that CPML is well suited for the simulation of borehole-GPR. 展开更多
关键词 卷积完全匹配层 数值模拟 吸收边界 钻孔雷达 时域有限差分法 完美匹配层 波场 基础
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A convolution-type semi-analytic DQ approach to transient response of rectangular plates
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作者 彭建设 杨杰 +1 位作者 袁玉全 罗光兵 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2009年第9期1143-1151,共9页
The convolution-type Gurtin variational principle is known as the only variational principle that is, from the mathematics point of view, totally equivalent to the initial value problem system. In this paper, the equa... The convolution-type Gurtin variational principle is known as the only variational principle that is, from the mathematics point of view, totally equivalent to the initial value problem system. In this paper, the equation of motion of rectangular thin plates is first transformed to a new governing equation containing initial conditions by using a convolution method. A convolution-type semi-analytical DQ approach, which involves differential quadrature (DQ) approximation in the space domain and an analytical series expansion in the time domain, is proposed to obtain the transient response solution. This approach offers the same advantages as the Gurtin variational principle and, at the same time, is much simpler in calculation. Numerical results show that it is very accurate yet computationally efficient for the dynamic response of plates. 展开更多
关键词 convolution transient response differential quadrature method semianalytical method
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Quantitative analysis modeling for the Chem Cam spectral data based on laser-induced breakdown spectroscopy using convolutional neural network
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作者 曹学强 张立 +3 位作者 武中臣 凌宗成 李加伦 郭恺琛 《Plasma Science and Technology》 SCIE EI CAS CSCD 2020年第11期81-90,共10页
Laser-induced breakdown spectroscopy(LIBS)has been applied to many fields for the quantitative analysis of diverse materials.Improving the prediction accuracy of LIBS regression models is still of great significance f... Laser-induced breakdown spectroscopy(LIBS)has been applied to many fields for the quantitative analysis of diverse materials.Improving the prediction accuracy of LIBS regression models is still of great significance for the Mars exploration in the near future.In this study,we explored the quantitative analysis of LIBS for the one-dimensional Chem Cam(an instrument containing a LIBS spectrometer and a Remote Micro-Imager)spectral data whose spectra are produced by the Chem Cam team using LIBS under the Mars-like atmospheric conditions.We constructed a convolutional neural network(CNN)regression model with unified parameters for all oxides,which is efficient and concise.CNN that has the excellent capability of feature extraction can effectively overcome the chemical matrix effects that impede the prediction accuracy of regression models.Firstly,we explored the effects of four activation functions on the performance of the CNN model.The results show that the CNN model with the hyperbolic tangent(tanh)function outperforms the CNN models with the other activation functions(the rectified linear unit function,the linear function and the Sigmoid function).Secondly,we compared the performance among the CNN models using different optimization methods.The CNN model with the stochastic gradient descent optimization and the initial learning rate?=?0.0005 achieves satisfactory performance compared to the other CNN models.Finally,we compared the performance of the CNN model,the model based on support vector regression(SVR)and the model based on partial least square regression(PLSR).The results exhibit the CNN model is superior to the SVR model and the PLSR model for all oxides.Based on the above analysis,we conclude the CNN regression model can effectively improve the prediction accuracy of LIBS. 展开更多
关键词 laser-induced breakdown spectroscopy convolutional neural network activation function optimization method quantitative analysis
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Convolutional Sparse Coding in Gradient Domain for MRI Reconstruction 被引量:1
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作者 Jiaojiao Xiong Hongyang Lu +1 位作者 Minghui Zhang Qiegen Liu 《自动化学报》 EI CSCD 北大核心 2017年第10期1841-1849,共9页
关键词 梯度图像 稀疏编码 MRI 卷积 应用 分割图像 空间采样 磁共振成像
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图卷积神经网络综述 被引量:1
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作者 谢娟英 张建宇 《陕西师范大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第2期89-101,共13页
图卷积神经网络是图论与深度学习的交叉,已成为机器学习领域的研究热点。基于此,介绍了图卷积神经网络的形成,梳理了两大类经典的图卷积神经网络:谱方法和空间方法,详细介绍了这两类图卷积神经网络模型,分析了图卷积操作的核心理论基础... 图卷积神经网络是图论与深度学习的交叉,已成为机器学习领域的研究热点。基于此,介绍了图卷积神经网络的形成,梳理了两大类经典的图卷积神经网络:谱方法和空间方法,详细介绍了这两类图卷积神经网络模型,分析了图卷积操作的核心理论基础,介绍了图卷积神经网络在各领域的应用,总结了图卷积神经网络面临的主要挑战,展望了图卷积神经网络的发展趋势,并分析了图卷积神经网络在野外环境下蝴蝶识别任务中的潜在应用。 展开更多
关键词 图卷积神经网络 谱方法 空间方法 目标检测
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基于卷积神经网络的采摘机械臂无碰撞运动规划研究 被引量:2
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作者 郭仓库 《农机化研究》 北大核心 2024年第3期42-46,共5页
介绍了卷积神经网络的基本结构及其工作原理,基于DH参数法建立了采摘机械臂运动模型,并设计了一套采摘机械臂无碰撞运动规划算法,旨在实现对采摘机械臂的精确控制。MatLab仿真试验表明:采摘机械臂在系统的驱动控制下,能够准确从起点移... 介绍了卷积神经网络的基本结构及其工作原理,基于DH参数法建立了采摘机械臂运动模型,并设计了一套采摘机械臂无碰撞运动规划算法,旨在实现对采摘机械臂的精确控制。MatLab仿真试验表明:采摘机械臂在系统的驱动控制下,能够准确从起点移动到目标点,轨迹比较圆滑,且能以最优的圆弧路径避开障碍物,优化效果明显,能够满足采摘机器人作业需求,证实了该算法的稳定性和可靠性。 展开更多
关键词 卷积神经网络 DH参数法 采摘机械臂 运动规划
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结合图卷积神经网络和集成方法的推荐系统恶意攻击检测
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作者 刘慧 纪科 +3 位作者 陈贞翔 孙润元 马坤 邬俊 《计算机科学》 CSCD 北大核心 2024年第S01期940-948,共9页
推荐系统已被广泛应用于电子商务、社交媒体、信息分享等大多数互联网平台中,有效解决了信息过载问题。然而,这些平台面向所有互联网用户开放,导致不法用户利用系统设计缺陷通过恶意干扰、蓄意攻击等行为非法操纵评分数据,进而影响推荐... 推荐系统已被广泛应用于电子商务、社交媒体、信息分享等大多数互联网平台中,有效解决了信息过载问题。然而,这些平台面向所有互联网用户开放,导致不法用户利用系统设计缺陷通过恶意干扰、蓄意攻击等行为非法操纵评分数据,进而影响推荐结果,严重危害推荐服务的安全性。现有的检测方法大多都是基于从评级数据中提取的人工构建特征进行的托攻击检测,难以适应更复杂的共同访问注入攻击,并且人工构建特征费时且区分能力不足,同时攻击行为规模远远小于正常行为,给传统检测方法带来了不平衡数据问题。因此,文中提出堆叠多层图卷积神经网络端到端学习用户和项目之间的多阶交互行为信息得到用户嵌入和项目嵌入,将其作为攻击检测特征,以卷积神经网络作为基分类器实现深度行为特征提取,结合集成方法检测攻击。在真实数据集上的实验结果表明,与流行的推荐系统恶意攻击检测方法相比,所提方法对共同访问注入攻击行为有较好的检测效果并在一定程度上克服了不平衡数据的难题。 展开更多
关键词 攻击检测 共同访问注入攻击 推荐系统 图卷积神经网络 卷积神经网络 集成方法
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基于轻量化深度卷积循环网络的MVS方法
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作者 佘维 孔祥基 +2 位作者 郭淑明 田钊 李英豪 《郑州大学学报(工学版)》 CAS 北大核心 2024年第4期11-18,共8页
针对基于深度学习的MVS方法存在网络参数量大、显存占用较高的问题,提出一种基于轻量化深度卷积循环网络的MVS方法。首先,采用轻量化多尺度特征提取网络提取图像的高层语义特征图,构建稀疏代价体减小计算体积;其次,使用卷积循环网络对... 针对基于深度学习的MVS方法存在网络参数量大、显存占用较高的问题,提出一种基于轻量化深度卷积循环网络的MVS方法。首先,采用轻量化多尺度特征提取网络提取图像的高层语义特征图,构建稀疏代价体减小计算体积;其次,使用卷积循环网络对代价体进行正则化,一次平面扫描完成正则化过程,减少显存占用;最后,通过深度图扩展模块扩展稀疏深度图为稠密深度图,并结合优化算法保证重建精度。在DTU数据集上与最近的方法进行对比,包括传统MVS方法Camp、Furu、Tola、Gipuma,基于深度学习的MVS方法SurfaceNet、PU-Net、MVSNet、R-MVSNet、Point-MVSNet、Fast-MVSNet、GBI-Net、TransMVSNet。实验结果表明:所提方法在精度上与其他方法保持较小差距的前提下,能够将预测时显存开销降低至3.1 GB。 展开更多
关键词 轻量化 深度卷积循环网络 MVS方法 正则化 DTU数据集
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数据驱动的半无限介质裂纹识别模型研究
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作者 江守燕 邓王涛 +1 位作者 孙立国 杜成斌 《力学学报》 EI CAS CSCD 北大核心 2024年第6期1727-1739,共13页
缺陷识别是结构健康监测的重要研究内容,对评估工程结构的安全性具有重要的指导意义,然而,准确确定结构缺陷的尺寸十分困难.论文提出了一种创新的数据驱动算法,将比例边界有限元法(scaled boundary finite element methods,SBFEM)与自... 缺陷识别是结构健康监测的重要研究内容,对评估工程结构的安全性具有重要的指导意义,然而,准确确定结构缺陷的尺寸十分困难.论文提出了一种创新的数据驱动算法,将比例边界有限元法(scaled boundary finite element methods,SBFEM)与自编码器(autoencoder,AE)、因果膨胀卷积神经网络(causal dilated convolutional neural network,CDCNN)相结合用于半无限介质中的裂纹识别.在该模型中,SBFEM用于模拟波在含不同裂纹状缺陷半无限介质中的传播过程,对于不同的裂纹状缺陷,仅需改变裂纹尖端的比例中心和裂纹开口处节点的位置,避免了复杂的重网格过程,可高效地生成足够的训练数据.模拟波在半无限介质中传播时,建立了基于瑞利阻尼的吸收边界模型,避免了对结构全域模型进行计算.搭建了CDCNN,确保了时序数据的有序性,并获得更大的感受野而不增加神经网络的复杂性,可捕捉更多的历史信息,AE具有较强的非线性特征提取能力,可将高维的原始输入特征向量空间映射到低维潜在特征向量空间,以获得低维潜在特征用于网络模型训练,有效提升了网络模型的学习效率.数值算例表明:提出的模型能够高效且准确地识别半无限介质中裂纹的量化信息,且AE-CDCNN模型的识别效率较单CDCNN模型提高了约2.7倍. 展开更多
关键词 数据驱动 比例边界有限元法 自编码器 因果膨胀卷积神经网络 裂纹识别
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Welch功率谱与卷积神经网络结合的滚动轴承故障诊断
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作者 金志浩 张旭 +1 位作者 张义民 张凯 《机械设计与制造》 北大核心 2024年第2期271-275,共5页
针对滚动轴承故障诊断在小训练样本下和强噪声下无法取得高精度识别的问题,提出一种基于Welch功率谱结合卷积神经网络进行诊断的方法。该方法以原始时域振动信号作为输入,用Welch功率谱转换数据形态同时对高强度噪声进行抑制,再用得到... 针对滚动轴承故障诊断在小训练样本下和强噪声下无法取得高精度识别的问题,提出一种基于Welch功率谱结合卷积神经网络进行诊断的方法。该方法以原始时域振动信号作为输入,用Welch功率谱转换数据形态同时对高强度噪声进行抑制,再用得到的功率谱训练卷积神经网络,最后将训练好的模型用于轴承的故障诊断。与WDCNN[1]等方法进行对比,实验发现在混合负载下,该方法平均识别率正确达到99%,其它方法达到这个精度至少需要20倍以上的训练样本量,明显优于WDCNN等方法。抗噪实验结果表明噪声对信号的干扰越强烈,该方法的抗噪表现越好,其抗噪性能要显著优于WDCNN等方法。 展开更多
关键词 故障诊断 卷积神经网络 滚动轴承 Welch功率谱 高精度识别
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