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ON POTENT ELEMENTS AND PSEUDO CLEAN RINGS
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作者 DING Yan GAO Han-peng +2 位作者 LIU Xin-yi YAN Zi-yi ZHANG Ting 《数学杂志》 2025年第1期39-47,共9页
In this paper,potent index of an element and pseudo clean rings are considered.Some properties and examples of pseudo clean rings are given.We also show that Zm is pseudo clean for every 2≤m∈Z and pseudo clean rings... In this paper,potent index of an element and pseudo clean rings are considered.Some properties and examples of pseudo clean rings are given.We also show that Zm is pseudo clean for every 2≤m∈Z and pseudo clean rings are clean.Furthermore,we prove pseudo clean rings are directly finite and have stable range one. 展开更多
关键词 clean rings strongly J-clean rings pseudo clean rings potent elements
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PNSS: Unknown Face Presentation Attack Detection with Pseudo Negative Sample Synthesis
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作者 Hongyang Wang Yichen Shi +2 位作者 Jun Feng Zitong Yu Zhuofu Tao 《Computers, Materials & Continua》 2025年第5期3097-3112,共16页
Face Presentation Attack Detection(fPAD)plays a vital role in securing face recognition systems against various presentation attacks.While supervised learning-based methods demonstrate effectiveness,they are prone to ... Face Presentation Attack Detection(fPAD)plays a vital role in securing face recognition systems against various presentation attacks.While supervised learning-based methods demonstrate effectiveness,they are prone to overfitting to known attack types and struggle to generalize to novel attack scenarios.Recent studies have explored formulating fPAD as an anomaly detection problem or one-class classification task,enabling the training of generalized models for unknown attack detection.However,conventional anomaly detection approaches encounter difficulties in precisely delineating the boundary between bonafide samples and unknown attacks.To address this challenge,we propose a novel framework focusing on unknown attack detection using exclusively bonafide facial data during training.The core innovation lies in our pseudo-negative sample synthesis(PNSS)strategy,which facilitates learning of compact decision boundaries between bonafide faces and potential attack variations.Specifically,PNSS generates synthetic negative samples within low-likelihood regions of the bonafide feature space to represent diverse unknown attack patterns.To overcome the inherent imbalance between positive and synthetic negative samples during iterative training,we implement a dual-loss mechanism combining focal loss for classification optimization with pairwise confusion loss as a regularizer.This architecture effectively mitigates model bias towards bonafide samples while maintaining discriminative power.Comprehensive evaluations across three benchmark datasets validate the framework’s superior performance.Notably,our PNSS achieves 8%–18% average classification error rate(ACER)reduction compared with state-of-the-art one-class fPAD methods in cross-dataset evaluations on Idiap Replay-Attack and MSU-MFSD datasets. 展开更多
关键词 Face presentation attack detection pseudo negative sample anomaly detection one-class classification
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Pseudo Label Purification with Dual Contrastive Learning for Unsupervised Vehicle Re-Identification
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作者 Jiyang Xu Qi Wang +4 位作者 Xin Xiong Weidong Min Jiang Luo Di Gai Qing Han 《Computers, Materials & Continua》 2025年第3期3921-3941,共21页
The unsupervised vehicle re-identification task aims at identifying specific vehicles in surveillance videos without utilizing annotation information.Due to the higher similarity in appearance between vehicles compare... The unsupervised vehicle re-identification task aims at identifying specific vehicles in surveillance videos without utilizing annotation information.Due to the higher similarity in appearance between vehicles compared to pedestrians,pseudo-labels generated through clustering are ineffective in mitigating the impact of noise,and the feature distance between inter-class and intra-class has not been adequately improved.To address the aforementioned issues,we design a dual contrastive learning method based on knowledge distillation.During each iteration,we utilize a teacher model to randomly partition the entire dataset into two sub-domains based on clustering pseudo-label categories.By conducting contrastive learning between the two student models,we extract more discernible vehicle identity cues to improve the problem of imbalanced data distribution.Subsequently,we propose a context-aware pseudo label refinement strategy that leverages contextual features by progressively associating granularity information from different bottleneck blocks.To produce more trustworthy pseudo-labels and lessen noise interference during the clustering process,the context-aware scores are obtained by calculating the similarity between global features and contextual ones,which are subsequently added to the pseudo-label encoding process.The proposed method has achieved excellent performance in overcoming label noise and optimizing data distribution through extensive experimental results on publicly available datasets. 展开更多
关键词 Unsupervised vehicle re-identification dual contrastive learning pseudo label refinement knowledge distillation
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Piecewise pseudo almost automorphic solution for impulsive Lasota-Wazewska model with mixed delays
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作者 Meryem Abdelaziz Farouk Cherif 《Applied Mathematics(A Journal of Chinese Universities)》 2025年第1期102-121,共20页
In this paper,the existence,uniqueness,asymptotic and global exponential stability of pseudo almost automorphic solution for a class of delayed Lasota-Wazewska model with impulsive effects are established by applying ... In this paper,the existence,uniqueness,asymptotic and global exponential stability of pseudo almost automorphic solution for a class of delayed Lasota-Wazewska model with impulsive effects are established by applying an appropriate fixed point theorem and Lyapunov functional method.Finally,a numerical example with simulation is given to illuminate our theoretical results. 展开更多
关键词 Lasota-Wazewska model existence and uniqueness pseudo almost automorphic asymptotic and exponential stability
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PSEUDO S-ASYMPTOTICALLY PERIODIC SOLUTIONS OF PARTIAL NEUTRAL DIFFERENTIAL EQUATIONS
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作者 LIU Jing-huai ZHANG Li-tao 《数学杂志》 2025年第2期140-150,共11页
In this paper,we study the existence of pseudo S-asymptotically ω-periodic mild solutions of abstract partial neutral differential equations in Banach spaces.By using the principle of Banach contractive mapping,the e... In this paper,we study the existence of pseudo S-asymptotically ω-periodic mild solutions of abstract partial neutral differential equations in Banach spaces.By using the principle of Banach contractive mapping,the existence and uniqueness of pseudo S-asymptotically ω-periodic mild solutions of abstract partial neutral differential equations are obtained.To illustrate the ab-stract result,a concrete example is given. 展开更多
关键词 pseudo S-asymptotically!-periodic function mild solution partial neutral differential equations
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Comment on“Integration of deep neural network modeling and LC-MS-based pseudo-targeted metabolomics as a practical strategy to differentiate ginseng species”
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作者 Li Ping 《Journal of Pharmaceutical Analysis》 2025年第2期289-290,共2页
Traditional Chinese medicine(TCM),especially the plant-based,represents complex chemical system containing various primary and secondary metabolites.These botanical metabolites are structurally diversified and exhibit... Traditional Chinese medicine(TCM),especially the plant-based,represents complex chemical system containing various primary and secondary metabolites.These botanical metabolites are structurally diversified and exhibit significant difference in the acidity,alkalinity,molecular weight,polarity,and content,etc,which thus poses great challenges in assessing the quality of TCM[1]. 展开更多
关键词 chemical system pseudo targeted metabolomics assessing quality LC MS traditional chinese medicine tcm especially primary secondary metabolitesthese ginseng species differentiation deep neural network
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Pseudo-Wellens' syndrome caused by myocardial bridge:a case report
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作者 Yingxin Zhao Yan Zhang +1 位作者 Chongzhe Pei Songtao Shou 《World Journal of Emergency Medicine》 2025年第3期298-300,共3页
Wellens’ syndrome is defined by specific T-wave inversions in the precordial leads of the electrocardiogram (ECG),which are indicative of acute anterior myocardial ischemia caused by severe proximal stenosis of the l... Wellens’ syndrome is defined by specific T-wave inversions in the precordial leads of the electrocardiogram (ECG),which are indicative of acute anterior myocardial ischemia caused by severe proximal stenosis of the left anterior descending (LAD)artery.If not promptly treated,approximately 75%of patients with Wellens’ syndrome may experience extensive anterior wall myocardial infarction or sudden cardiac death within days to weeks.^([1,2]) Although the characteristic ECG changes associated with Wellens’syndrome are highly suggestive of LAD occlusion,there are rare instances in which similar ECG alterations are observed in the absence of LAD stenosis,a phenomenon referred to as pseudo-Wellens’ syndrome.The precise pathophysiological mechanisms underlying this syndrome remain unclear.Here,we present a patient with a myocardial bridge who presented a typical Wellens’ECG pattern. 展开更多
关键词 pseudo wellens syndrome Wellens syndrome sudden cardiac death severe proximal stenosis anterior wall myocardial infarction wellens syndrome ELECTROCARDIOGRAM acute anterior myocardial ischemia
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Laboratory Implementation of Direct Torque Controller based Speed Loop Pseudo Derivative Feedforward Controller for PMSM Drive 被引量:3
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作者 Prabhakaran Koothu Kesavan Umashankar Subramaniam Dhafer J.Almakhles 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第1期12-21,共10页
This paper,evaluate the effectiveness of a proposed speed loop pseudo derivative feedforward(PDFF)controller-based direct torque controller(DTC)for a PMSM drive against the performance of existing PI speed controller-... This paper,evaluate the effectiveness of a proposed speed loop pseudo derivative feedforward(PDFF)controller-based direct torque controller(DTC)for a PMSM drive against the performance of existing PI speed controller-based DTC and hysteresis current controller(HCC).The proposed PDFF-based speed regulator effectively reduces oscillation and overshoot associated with rotor angular speed,electromagnetic torque,and stator current.Two case studies,one using forward-to-reverse motoring operation and the other involving reverse-to-forward braking operation,has been validated to show the effectiveness of the proposed control strategy.The proposed controller's superior performance is demonstrated through experimental verification utilizing an FPGA controller for a 1.5 kW PMSM drive laboratory prototype. 展开更多
关键词 Direct torque control pseudo derivative feedforward controller Permanent magnet synchronous motor(PMSM)
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基于高斯滤波的双目相机三维目标检测Pseudo-LiDAR改进算法研究 被引量:1
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作者 李艳明 苏建强 +1 位作者 刘鹏 张丽杰 《光学技术》 CAS CSCD 北大核心 2024年第6期713-720,共8页
Pseudo-LiDAR算法作为双目相机三维目标检测的通用算法之一,因其低成本的立体视觉方案及出色的适应性被广泛应用于在自动驾驶、机器人等领域。但该算法在预测物体边缘会产生过多畸变点从而导致目标与背景之间过渡区域估计误差大;且深度... Pseudo-LiDAR算法作为双目相机三维目标检测的通用算法之一,因其低成本的立体视觉方案及出色的适应性被广泛应用于在自动驾驶、机器人等领域。但该算法在预测物体边缘会产生过多畸变点从而导致目标与背景之间过渡区域估计误差大;且深度估计网络采用四分支结构,计算量大影响运行速度。对以上问题,将Pseudo-LiDAR算法中的Spatial Pyramid Pooling(SPP)四分支结构优化为单分支结构,提高运行速度;创新性构造高斯置信度滤波模块,滤除过渡区域误差大的数据;引入PointVoxel-RCNN(PV-RCNN)作为Pseudo-LiDAR算法中的三维目标检测网络,提升检测精度。在KITTI数据集上的实验结果表明,相较于原算法,在简单、中等和困难等级下的车辆目标三维检测平均精度分别提升了22.36%、26.48%和28.55%。 展开更多
关键词 三维目标检测 双目相机 高斯置信度 pseudo-LiDAR算法
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A new approach for pseudo hyperbolic partial differential equations with nonLocal conditions using Laplace Adomian decomposition method
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作者 Mahmut Modanli Sadeq Taha Abdulazeez Ahmad Muhamad Husien 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第4期750-758,共9页
This paper provides a nonlinear pseudo-hyperbolic partial differential equation with non-local conditions.Despite the importance of this problem,the exact solution to this problem is rare in the literature.Therefore,t... This paper provides a nonlinear pseudo-hyperbolic partial differential equation with non-local conditions.Despite the importance of this problem,the exact solution to this problem is rare in the literature.Therefore,the Laplace-Adomian Decomposition Method(LADM)is used to provide a new approach to solving this problem.Additionally,we give a comparison between the exact and approximate solutions at various points with absolute error.The obtained result showed that the proposed method is effective and accurate for this problem and can be used for many other evolution of nonlinear equations in mathematical physics. 展开更多
关键词 pseudo hyperbolic equations nonlocal conditions Laplace-Adomian decomposition method Approximate solutions
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Spatio-temporal characteristics and influencing factors of Pseudo Human Settlements in Northeast China based on the Baidu Index
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作者 LI Xueming ZHANG Xiaohui +2 位作者 TIAN Shenzhen GAO Mengke YANG Jun 《Journal of Geographical Sciences》 SCIE CSCD 2024年第12期2333-2363,共31页
Pseudo Human Settlements(PHS)are a fundamental element in human settlements geography,serving as an innovative frontier in the exploration of human–land relationships.Since entering the information age,PHS have emerg... Pseudo Human Settlements(PHS)are a fundamental element in human settlements geography,serving as an innovative frontier in the exploration of human–land relationships.Since entering the information age,PHS have emerged as a new catalyst for people's lives and urban development.Based on the Baidu Index,cold hot spot analysis and the Pearson correlation coefficient method were used to evaluate the spatiotemporal variation characteristics of the development of the quality of PHS at different levels in the three provinces of Northeast China(TPNC)during 2011–2022 and to characterize the influence of the system and factors.The results indicated that:1)temporally,PHS exhibits significant fluctuations,with an overall pattern of rapid increase followed by a gradual decline;2)spatially,PHS is marked by regional differentiation,with“three-core”dominance and a“cluster-like”distribution;3)systematically,the five major PHS systems generally exhibit an ascending and then a descending trend;4)in terms of influence,the socialization system serves as the core influence of PHS,with WeChat,JD.COM,and others are identified as the core influencing factors of subsystems.The findings of this study can provide scientific guidance for diversifying approaches to human settlements,promoting sustainable urban development,and revitalizing Northeast China. 展开更多
关键词 Baidu Index pseudo Human Settlements quality index three provinces of Northeast China spatio-temporal variation
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Pseudo channel:time embedding for motor imagery decoding
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作者 MIAO Zhengqing ZHAO Meirong 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2024年第3期308-317,共10页
Motor imagery(MI)based electroencephalogram(EEG)represents a frontier in enabling direct neural control of external devices and advancing neural rehabilitation.This study introduces a novel time embedding technique,te... Motor imagery(MI)based electroencephalogram(EEG)represents a frontier in enabling direct neural control of external devices and advancing neural rehabilitation.This study introduces a novel time embedding technique,termed traveling-wave based time embedding,utilized as a pseudo channel to enhance the decoding accuracy of MI-EEG signals across various neural network architectures.Unlike traditional neural network methods that fail to account for the temporal dynamics in MI-EEG in individual difference,our approach captures time-related changes for different participants based on a priori knowledge.Through extensive experimentation with multiple participants,we demonstrate that this method not only improves classification accuracy but also exhibits greater adaptability to individual differences compared to position encoding used in Transformer architecture.Significantly,our results reveal that traveling-wave based time embedding crucially enhances decoding accuracy,particularly for participants typically considered“EEG-illiteracy”.As a novel direction in EEG research,the traveling-wave based time embedding not only offers fresh insights for neural network decoding strategies but also expands new avenues for research into attention mechanisms in neuroscience and a deeper understanding of EEG signals. 展开更多
关键词 motor imagery(MI) pseudo channel electroencephalogram(EEG) neural networks
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Long‐life lithium batteries enabled by a pseudo‐oversaturated electrolyte
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作者 Youchun Yu Simeng Wang +6 位作者 Juyan Zhang Weiwei Qian Nana Zhang Guangjie Shao Haiyan Bian Yuwen Liu Lan Zhang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第4期115-127,共13页
The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging f... The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging for the liquid electrolyte.Herein,a novel pseudo‐oversaturated electrolyte(POSE)is prepared by introducing 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether(TTE)to adjust the coordination structure between diglyme(G2)and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI).Surprisingly,although TTE shows little solubility to LiTFSI,the molar ratio between LiTFSI and G2 in the POSE can be increased to 1:1,which is much higher than that of the saturation state,1:2.8.Simulation and experimental results prove that TTE promotes closer contact of the G2 molecular with Li^(+)in the POSE.Moreover,it also participates in the formation of electrolyte/electrode interphases.The electrolyte shows outstanding compatibility with both the Li metal anode and typical high‐voltage cathodes.Li||Li symmetric cells show a long life of more than 2000 h at 1 mA cm^(−2),1 mAh cm^(−2).In the meantime,Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cell with the POSE shows a high reversible capacity of 134.8 mAh g^(−1 )after 900 cycles at 4.5 V,1 C rate.The concept of POSE can provide new insight into the Li^(+)solvation structure and in the design of advanced electrolytes for LMBs. 展开更多
关键词 high voltage lithium metal batteries pseudo‐oversaturated electrolyte solid electrolyte interphases(SEI) solvation structure
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Pseudo S-Asymptotically(ω,c)-Periodic Solutions to Fractional Differential Equations of Sobolev Type
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作者 MAO Hang-ning CHANG Yong-kui 《Chinese Quarterly Journal of Mathematics》 2024年第3期295-306,共12页
In this paper,we firstly recall some basic results on pseudo S-asymptotically(ω,c)-periodic functions and Sobolev type fractional differential equation.We secondly investigate some existence of pseudo S-asymptotical... In this paper,we firstly recall some basic results on pseudo S-asymptotically(ω,c)-periodic functions and Sobolev type fractional differential equation.We secondly investigate some existence of pseudo S-asymptotically(ω,c)-periodic solutions for a semilinear fractional differential equations of Sobolev type.We finally present a simple example. 展开更多
关键词 pseudo S-asymptotically(ω c)-periodic functions Evolution equations Sobolev type Fractional differential equations Existence and uniqueness
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利用多层次特征融合网络的图像异常检测算法 被引量:2
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作者 唐俊 左金梅 +2 位作者 王科 张艳 王年 《国防科技大学学报》 北大核心 2025年第2期173-182,共10页
图像异常检测旨在识别并定位图像中的异常区域,针对现有算法中不同层次特征信息利用不充分的问题,提出了基于多层次特征融合网络的图像异常检测算法。通过使用融合了异常先验知识的伪异常数据生成算法,对训练集进行了异常数据扩充,将异... 图像异常检测旨在识别并定位图像中的异常区域,针对现有算法中不同层次特征信息利用不充分的问题,提出了基于多层次特征融合网络的图像异常检测算法。通过使用融合了异常先验知识的伪异常数据生成算法,对训练集进行了异常数据扩充,将异常检测任务转化为监督学习任务;构建了多层次特征融合网络,将神经网络中不同层次特征进行融合,丰富了特征中的低层纹理信息和高层语义信息,使得用于异常检测的特征更具区分性;训练时,设计了分数约束损失和一致性约束损失,并结合特征约束损失对整个网络模型进行训练。实验结果表明,MVTec数据集上图像级检测接收机工作特性曲线下面积(area under the receiver operating characteristic, AUROC)平均值为98.7%,像素级定位AUROC平均值为97.9%,每区域重叠率平均值为94.2%,均高于现有的异常检测算法。 展开更多
关键词 图像异常检测 伪异常 多层次特征融合 一致性约束
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基于CNN和Transformer交叉教学的半监督医学图像分割 被引量:4
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作者 杨云 胡雯青 +1 位作者 杨虹 吴亚男 《陕西科技大学学报》 北大核心 2025年第1期185-192,共8页
由于医学图像分割领域缺乏高质量的标注数据,半监督学习方法在医学图像语义分割任务中受到高度重视.为了充分利用卷积神经网络(Convolutional Neural Network,CNN)和Transformer在半监督学习中的优势,本文提出一种基于CNN与Transformer... 由于医学图像分割领域缺乏高质量的标注数据,半监督学习方法在医学图像语义分割任务中受到高度重视.为了充分利用卷积神经网络(Convolutional Neural Network,CNN)和Transformer在半监督学习中的优势,本文提出一种基于CNN与Transformer交叉教学的半监督医学图像分割方法.该方法将经典的深度协同训练从一致性正则化简化为交叉教学,利用循环伪标签方案使两个网络的预测差异转换为无监督损失,以鼓励两个网络具有一致的低熵预测.所提方法在ISIC 2018数据集上进行实验,在采用20%的标注比例时,Dice系数和Jaccard系数分别达到87.25%和79.17%,相比于监督U-Net++的训练结果分别提升了2.89%和3.53%,并且优于目前主流的半监督学习方法,验证了所提方法在半监督医学图像分割上的有效性和泛化性. 展开更多
关键词 半监督学习 图像语义分割 交叉教学 循环伪标签
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融合灰度和深度特征的钢管表面缺陷检测方法 被引量:1
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作者 石杰 吴昆鹏 +3 位作者 杨朝霖 邓能辉 王少聪 苏成 《机械工程学报》 北大核心 2025年第4期32-43,共12页
无缝钢管的表面缺陷检测与量化对于质量判定至关重要。然而,现有的检测方法主要依赖于灰度图像分析,缺乏对缺陷深度的综合判断,因此检测结果往往片面且不准确。为解决该问题,设计采用3D相机采集钢管表面的数据,能够同步获取到具备相同... 无缝钢管的表面缺陷检测与量化对于质量判定至关重要。然而,现有的检测方法主要依赖于灰度图像分析,缺乏对缺陷深度的综合判断,因此检测结果往往片面且不准确。为解决该问题,设计采用3D相机采集钢管表面的数据,能够同步获取到具备相同尺寸的灰度图像和点云数据,通过对点云数据的处理,可以计算出缺陷相对于基准表面的深度,并进一步量化得到伪彩色深度图像,能够直观地展示缺陷的深度信息。为了提升缺陷检测能力,在Yolov5模型的基础上添加双边网络结构,将灰度图像和伪彩色深度图像分别输入到细节分支和语义分支中提取特征,融合两分支的数据得到新的中间特征用于目标检测。试验结果表明,利用相对深度测量方法生成的伪彩色深度图像可以有效地消除抖动、扭转等情况的干扰,深度测量误差小于0.1 mm。此外,与传统的灰度图像检测模式相比,添加了双边网络结构的Yolov5模型在m AP指标上提升了4.7%,并且以108帧/s的速率满足了实时检测的要求。最终在缺陷定性分析的基础上,通过增加深度方向维度,实现了对缺陷的定量分析,不仅提升了检测的全面性,也显著提高了检测的准确度。 展开更多
关键词 缺陷检测 轮廓拟合 伪彩色深度图像 Yolov5 双边网络
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基于多层域适应的无标签数据故障诊断方法 被引量:1
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作者 王进花 刘瑞 曹洁 《北京航空航天大学学报》 北大核心 2025年第4期1185-1194,共10页
在工业生产中,由于源域数据和目标域数据分布有差异且有标签的故障数据量较少,以至于现有的域适应轴承故障诊断方法大多精度不高。基于此,提出多层域适应神经网络(MDANN)故障诊断方法,用于无标签数据的滚动轴承故障诊断。使用小波包分... 在工业生产中,由于源域数据和目标域数据分布有差异且有标签的故障数据量较少,以至于现有的域适应轴承故障诊断方法大多精度不高。基于此,提出多层域适应神经网络(MDANN)故障诊断方法,用于无标签数据的滚动轴承故障诊断。使用小波包分解与重构(WPT)对原始振动信号进行处理,以降低信号冗余并避免关键信号特征遗失;利用多核最大均值差异(MKMMD)算法对输入特征值进行差异计算,并通过反向传播更新多层域适应神经网络的参数,使其能够提取域不变特征;为保证无标签目标域数据可以正常参与网络训练,使用最大概率标签作为真实标签的伪标签策略,解决目标域无标签数据无法训练问题,增强模型可靠诊断知识的获取。采用2个公开数据集CWRU和PU进行验证。实验结果表明:所提方法与常见的域适应方法对比具有更高的诊断精度,说明该方法能够有效地学习可迁移特征,拟合2个数据集之间的数据分布差异。 展开更多
关键词 滚动轴承 故障诊断 迁移学习 多层域适应 伪标签策略
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基于波动方程的地震波数值模拟研究综述 被引量:3
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作者 李航 孙宇航 +2 位作者 李佳慧 李学贵 董宏丽 《吉林大学学报(地球科学版)》 北大核心 2025年第2期627-645,共19页
地震波场数值模拟在地震勘探、地震资料处理和地球构造研究等方面发挥着重要的作用。波动方程数值模拟方法充分考虑了地震波传播的动力学特征和几何学特征,可以为地震波传播机理的研究和复杂地层的解释提供强有力的理论支持,是目前应用... 地震波场数值模拟在地震勘探、地震资料处理和地球构造研究等方面发挥着重要的作用。波动方程数值模拟方法充分考虑了地震波传播的动力学特征和几何学特征,可以为地震波传播机理的研究和复杂地层的解释提供强有力的理论支持,是目前应用较为广泛的地震波场数值模拟方法之一。本文调研了五种基于波动方程的数值模拟方法:有限差分法易于理解,但数值频散问题明显;伪谱法精度高,但计算效率低;有限元法适用于复杂模型,但计算资源消耗大;谱元法适合高精度问题,但对计算内存需求较高;基于物理信息神经网络的深度学习法具有较强的适应性,但训练成本较高。并分别叙述了这五种数值模拟方法的理论基础、适用条件和最新进展。未来,地震波场数值模拟方法应结合深度学习等最新技术,优化边界条件模拟真实的边界反射情况,提高模拟的精度和效率。 展开更多
关键词 波场模拟 有限差分法 伪谱法 有限元法 谱元法 物理信息神经网络
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UHPC缀板-钢管混凝土复合柱地震响应及数值模拟 被引量:1
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作者 韦建刚 应浩东 杨艳 《交通运输工程学报》 北大核心 2025年第3期82-100,共19页
为研究超高性能混凝土(UHPC)缀板-钢管混凝土复合柱的地震响应特性,设计制作了2根1∶8缩尺试件,并以地震动特性、地震动强度、轴压比以及缀板材料为试验参数开展拟动力试验研究,随后基于OpenSees软件建立足尺模型开展数值模拟研究,最终... 为研究超高性能混凝土(UHPC)缀板-钢管混凝土复合柱的地震响应特性,设计制作了2根1∶8缩尺试件,并以地震动特性、地震动强度、轴压比以及缀板材料为试验参数开展拟动力试验研究,随后基于OpenSees软件建立足尺模型开展数值模拟研究,最终提出足尺结构在E1、E2地震荷载下响应位移的计算方法。研究结果表明:地震动特性显著影响试件的地震响应,试件S1、S2在同等小震强度的不同地震动下,其最大响应位移分别为最小响应位移的4.16倍和4.89倍;随着地震动强度不断增加,试件经历了弹性、弹塑性以及塑形破坏阶段;两试件破坏形态基本相似,均为整体压弯型破坏,表现为底部UHPC缀板开裂,钢缀条发生局部屈曲变形,柱肢钢管底部形成屈曲环或发生全截面撕裂;轴压比对于试件初始侧向刚度影响不大,但是轴压比越大,试件初始应力越大,柱肢钢管发生屈服和屈曲变形的时间越早,最后的破坏现象也更为剧烈;同等强度地震动下,UHPC缀板-钢管混凝土复合柱相较于普通混凝土缀板钢管混凝土复合柱,其初始侧向刚度提高约13.7%,刚度退化得到一定程度上的延缓,且累积滞回耗能提高了约41.2%;足尺模型的数值模拟分析结果显示长细比为影响试件地震响应以及放大系数的关键因素;所提出的足尺试件在E1、E2地震下响应位移计算方法具有良好精度。 展开更多
关键词 桥梁工程 复合柱 地震响应 拟动力试验 计算方法 UHPC缀板
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