期刊文献+
共找到3,168篇文章
< 1 2 159 >
每页显示 20 50 100
Occluded Gait Emotion Recognition Based on Multi-Scale Suppression Graph Convolutional Network
1
作者 Yuxiang Zou Ning He +2 位作者 Jiwu Sun Xunrui Huang Wenhua Wang 《Computers, Materials & Continua》 SCIE EI 2025年第1期1255-1276,共22页
In recent years,gait-based emotion recognition has been widely applied in the field of computer vision.However,existing gait emotion recognition methods typically rely on complete human skeleton data,and their accurac... In recent years,gait-based emotion recognition has been widely applied in the field of computer vision.However,existing gait emotion recognition methods typically rely on complete human skeleton data,and their accuracy significantly declines when the data is occluded.To enhance the accuracy of gait emotion recognition under occlusion,this paper proposes a Multi-scale Suppression Graph ConvolutionalNetwork(MS-GCN).TheMS-GCN consists of three main components:Joint Interpolation Module(JI Moudle),Multi-scale Temporal Convolution Network(MS-TCN),and Suppression Graph Convolutional Network(SGCN).The JI Module completes the spatially occluded skeletal joints using the(K-Nearest Neighbors)KNN interpolation method.The MS-TCN employs convolutional kernels of various sizes to comprehensively capture the emotional information embedded in the gait,compensating for the temporal occlusion of gait information.The SGCN extracts more non-prominent human gait features by suppressing the extraction of key body part features,thereby reducing the negative impact of occlusion on emotion recognition results.The proposed method is evaluated on two comprehensive datasets:Emotion-Gait,containing 4227 real gaits from sources like BML,ICT-Pollick,and ELMD,and 1000 synthetic gaits generated using STEP-Gen technology,and ELMB,consisting of 3924 gaits,with 1835 labeled with emotions such as“Happy,”“Sad,”“Angry,”and“Neutral.”On the standard datasets Emotion-Gait and ELMB,the proposed method achieved accuracies of 0.900 and 0.896,respectively,attaining performance comparable to other state-ofthe-artmethods.Furthermore,on occlusion datasets,the proposedmethod significantly mitigates the performance degradation caused by occlusion compared to other methods,the accuracy is significantly higher than that of other methods. 展开更多
关键词 KNN interpolation multi-scale temporal convolution suppression graph convolutional network gait emotion recognition human skeleton
下载PDF
基于改进Harris鹰优化的无线传感器网络分簇协议 被引量:1
2
作者 胡黄水 范新纪 邓育欢 《吉林大学学报(理学版)》 CAS 北大核心 2024年第5期1228-1234,共7页
针对无线传感器网络因能量效率低而导致网络生命周期短的问题,提出一种新的基于改进Harris鹰优化算法的无线传感器网络分簇协议(improved Harris hawk optimization based clustering protocols for wireless sensor networks, IHHOC). ... 针对无线传感器网络因能量效率低而导致网络生命周期短的问题,提出一种新的基于改进Harris鹰优化算法的无线传感器网络分簇协议(improved Harris hawk optimization based clustering protocols for wireless sensor networks, IHHOC). IHHOC采用改进的Harris鹰优化算法获得最优簇头集,首先通过Sobol序列初始化种群,并考虑剩余能量、与基站距离以及节点密度这3个参数定义适应度函数,通过探索、过渡和开发逐次迭代最终求得最优解;其次,采用高斯随机游走策略避免IHHOC陷入局部最优.成簇后,在簇头邻近簇中基于剩余能量、与簇头和基站距离找到最优转发节点,进一步降低网络能量消耗.仿真实验结果表明,IHHOC能有效提高网络能量效率,增大网络吞吐量,延长网络生命周期. 展开更多
关键词 无线传感器网络 分簇 harris鹰优化 网络生命周期
下载PDF
闭合复位交叉克氏针内固定治疗儿童桡骨远端Salter-Harris Ⅱ型骨折
3
作者 田野 侯婷婷 《临床骨科杂志》 2024年第5期694-697,共4页
目的 探讨闭合复位交叉克氏针内固定治疗儿童桡骨远端Salter-HarrisⅡ型骨折的疗效。方法 采用闭合复位交叉克氏针内固定治疗38例桡骨远端Salter-HarrisⅡ型骨折患儿。记录骨折复位及愈合情况、术后并发症发生情况、腕关节活动度。采用G... 目的 探讨闭合复位交叉克氏针内固定治疗儿童桡骨远端Salter-HarrisⅡ型骨折的疗效。方法 采用闭合复位交叉克氏针内固定治疗38例桡骨远端Salter-HarrisⅡ型骨折患儿。记录骨折复位及愈合情况、术后并发症发生情况、腕关节活动度。采用Gartland-Werley评分标准评价腕关节功能。结果 患儿均获得随访,时间3~6个月。骨折均解剖复位。骨折临床愈合时间4~6周,骨性愈合时间3~6个月。患儿均未发生骨折复位丢失、骨骺早闭及腕关节发育畸形等并发症,1例发生指伸肌损伤。末次随访时,腕关节活动度均恢复正常,其中掌屈50°~60°,背伸30°~60°,尺偏30°~40°,桡偏25°~30°;采用Gartland-Werley评分标准评价腕关节功能:优36例,良1例,可1例,优良率97.37%。结论 闭合复位交叉克氏针内固定治疗儿童桡骨远端Salter-HarrisⅡ型骨折,具有创伤小、骨折端固定稳定、患儿可早期功能锻炼、术后并发症少等优点。 展开更多
关键词 桡骨远端Salter-harrisⅡ型骨折 闭合复位 交叉克氏针固定 儿童
下载PDF
基于多尺度Harris角点检测的图像配准算法 被引量:3
4
作者 尚明姝 王克朝 《电光与控制》 CSCD 北大核心 2024年第1期28-32,共5页
针对现有多尺度Harris算子算法较复杂、运算量大、精确性一般的问题,提出一种高效简便算法。首先建立多尺度空间,令Harris算子在尺度空间提取特征点,用简化的32维SIFT特征向量描述特征。利用最近邻法匹配特征点;然后采用改进的相似三角... 针对现有多尺度Harris算子算法较复杂、运算量大、精确性一般的问题,提出一种高效简便算法。首先建立多尺度空间,令Harris算子在尺度空间提取特征点,用简化的32维SIFT特征向量描述特征。利用最近邻法匹配特征点;然后采用改进的相似三角形法筛选匹配点,再使用改进的K-means算法对特征点分组,使组内特征点聚集,组间特征点远离;最后应用改进的RANSAC算法在不同组中选取特征点求变换矩阵,避免了选取的特征点距离过近,算法陷入局部最优。实验验证了所提算法的性能。 展开更多
关键词 图像配准 尺度空间 harris K-MEANS RANSAC
下载PDF
A semi-analytical model for coupled flow in stress-sensitive multi-scale shale reservoirs with fractal characteristics 被引量:2
5
作者 Qian Zhang Wen-Dong Wang +4 位作者 Yu-Liang Su Wei Chen Zheng-Dong Lei Lei Li Yong-Mao Hao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期327-342,共16页
A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes... A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes due to stress sensitivity, which plays a crucial role in controlling pressure propagation and oil flow. This paper proposes a multi-scale coupled flow mathematical model of matrix nanopores, induced fractures, and hydraulic fractures. In this model, the micro-scale effects of shale oil flow in fractal nanopores, fractal induced fracture network, and stress sensitivity of multi-scale media are considered. We solved the model iteratively using Pedrosa transform, semi-analytic Segmented Bessel function, Laplace transform. The results of this model exhibit good agreement with the numerical solution and field production data, confirming the high accuracy of the model. As well, the influence of stress sensitivity on permeability, pressure and production is analyzed. It is shown that the permeability and production decrease significantly when induced fractures are weakly supported. Closed induced fractures can inhibit interporosity flow in the stimulated reservoir volume (SRV). It has been shown in sensitivity analysis that hydraulic fractures are beneficial to early production, and induced fractures in SRV are beneficial to middle production. The model can characterize multi-scale flow characteristics of shale oil, providing theoretical guidance for rapid productivity evaluation. 展开更多
关键词 multi-scale coupled flow Stress sensitivity Shale oil Micro-scale effect Fractal theory
下载PDF
Multi-scale physics-informed neural networks for solving high Reynolds number boundary layer flows based on matched asymptotic expansions 被引量:2
6
作者 Jianlin Huang Rundi Qiu +1 位作者 Jingzhu Wang Yiwei Wang 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2024年第2期76-81,共6页
Multi-scale system remains a classical scientific problem in fluid dynamics,biology,etc.In the present study,a scheme of multi-scale Physics-informed neural networks is proposed to solve the boundary layer flow at hig... Multi-scale system remains a classical scientific problem in fluid dynamics,biology,etc.In the present study,a scheme of multi-scale Physics-informed neural networks is proposed to solve the boundary layer flow at high Reynolds numbers without any data.The flow is divided into several regions with different scales based on Prandtl's boundary theory.Different regions are solved with governing equations in different scales.The method of matched asymptotic expansions is used to make the flow field continuously.A flow on a semi infinite flat plate at a high Reynolds number is considered a multi-scale problem because the boundary layer scale is much smaller than the outer flow scale.The results are compared with the reference numerical solutions,which show that the msPINNs can solve the multi-scale problem of the boundary layer in high Reynolds number flows.This scheme can be developed for more multi-scale problems in the future. 展开更多
关键词 Physics-informed neural networks(PINNs) multi-scale Fluid dynamics Boundary layer
下载PDF
基于Canny-Harris角点检测的光学元件表面疵病检测 被引量:1
7
作者 王赛赛 周阿维 《机械与电子》 2024年第8期26-33,共8页
为提高光学元件表面疵病检测的准确性,提出了一种基于Canny-Harris角点检测的光学元件表面疵病检测方法。该方法首先利用基于迭代式阈值的Canny算子对图像进行边缘检测,得到候选角点;接着,利用基于局部窗口角点密度的可变窗口非极大值... 为提高光学元件表面疵病检测的准确性,提出了一种基于Canny-Harris角点检测的光学元件表面疵病检测方法。该方法首先利用基于迭代式阈值的Canny算子对图像进行边缘检测,得到候选角点;接着,利用基于局部窗口角点密度的可变窗口非极大值抑制方法去除候选角点中的伪角点,以得到检测精度更高的Canny-Harris角点检测算法;然后,利用Canny-Harris角点检测算法进行图像拼接,并利用边界测定法提取出拼接图像中的疵病特征;最后,通过计算疵病的形状因子,实现对疵病的分类。实验结果表明,该方法能够成功实现子孔径图像的精确拼接,并准确地检测出光学元件表面疵病信息。 展开更多
关键词 光学元件 疵病检测 Canny-harris算法 图像拼接 疵病识别
下载PDF
Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets 被引量:1
8
作者 Hanxiao GUO Peifeng GAO Xingzhe WANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第5期747-762,共16页
Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting app... Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting applications.With respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic fields.Traditional numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally demanding.Herein,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake coils.This approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic scale.We then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic scale.The results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and efficient.The proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets. 展开更多
关键词 epoxy-impregnated high-temperature superconducting(HTS)magnet multi-scale method global homogenization(GH) local refinement(LR) multi-field analysis
下载PDF
MSD-Net: Pneumonia Classification Model Based on Multi-Scale Directional Feature Enhancement
9
作者 Tao Zhou Yujie Guo +3 位作者 Caiyue Peng Yuxia Niu Yunfeng Pan Huiling Lu 《Computers, Materials & Continua》 SCIE EI 2024年第6期4863-4882,共20页
Computer-aided diagnosis of pneumonia based on deep learning is a research hotspot.However,there are some problems that the features of different sizes and different directions are not sufficient when extracting the f... Computer-aided diagnosis of pneumonia based on deep learning is a research hotspot.However,there are some problems that the features of different sizes and different directions are not sufficient when extracting the features in lung X-ray images.A pneumonia classification model based on multi-scale directional feature enhancement MSD-Net is proposed in this paper.The main innovations are as follows:Firstly,the Multi-scale Residual Feature Extraction Module(MRFEM)is designed to effectively extract multi-scale features.The MRFEM uses dilated convolutions with different expansion rates to increase the receptive field and extract multi-scale features effectively.Secondly,the Multi-scale Directional Feature Perception Module(MDFPM)is designed,which uses a three-branch structure of different sizes convolution to transmit direction feature layer by layer,and focuses on the target region to enhance the feature information.Thirdly,the Axial Compression Former Module(ACFM)is designed to perform global calculations to enhance the perception ability of global features in different directions.To verify the effectiveness of the MSD-Net,comparative experiments and ablation experiments are carried out.In the COVID-19 RADIOGRAPHY DATABASE,the Accuracy,Recall,Precision,F1 Score,and Specificity of MSD-Net are 97.76%,95.57%,95.52%,95.52%,and 98.51%,respectively.In the chest X-ray dataset,the Accuracy,Recall,Precision,F1 Score and Specificity of MSD-Net are 97.78%,95.22%,96.49%,95.58%,and 98.11%,respectively.This model improves the accuracy of lung image recognition effectively and provides an important clinical reference to pneumonia Computer-Aided Diagnosis. 展开更多
关键词 PNEUMONIA X-ray image ResNet multi-scale feature direction feature TRANSFORMER
下载PDF
Multi-scale context-aware network for continuous sign language recognition
10
作者 Senhua XUE Liqing GAO +1 位作者 Liang WAN Wei FENG 《虚拟现实与智能硬件(中英文)》 EI 2024年第4期323-337,共15页
The hands and face are the most important parts for expressing sign language morphemes in sign language videos.However,we find that existing Continuous Sign Language Recognition(CSLR)methods lack the mining of hand an... The hands and face are the most important parts for expressing sign language morphemes in sign language videos.However,we find that existing Continuous Sign Language Recognition(CSLR)methods lack the mining of hand and face information in visual backbones or use expensive and time-consuming external extractors to explore this information.In addition,the signs have different lengths,whereas previous CSLR methods typically use a fixed-length window to segment the video to capture sequential features and then perform global temporal modeling,which disturbs the perception of complete signs.In this study,we propose a Multi-Scale Context-Aware network(MSCA-Net)to solve the aforementioned problems.Our MSCA-Net contains two main modules:(1)Multi-Scale Motion Attention(MSMA),which uses the differences among frames to perceive information of the hands and face in multiple spatial scales,replacing the heavy feature extractors;and(2)Multi-Scale Temporal Modeling(MSTM),which explores crucial temporal information in the sign language video from different temporal scales.We conduct extensive experiments using three widely used sign language datasets,i.e.,RWTH-PHOENIX-Weather-2014,RWTH-PHOENIX-Weather-2014T,and CSL-Daily.The proposed MSCA-Net achieve state-of-the-art performance,demonstrating the effectiveness of our approach. 展开更多
关键词 Continuous sign language recognition multi-scale motion attention multi-scale temporal modeling
下载PDF
YOLO-MFD:Remote Sensing Image Object Detection with Multi-Scale Fusion Dynamic Head
11
作者 Zhongyuan Zhang Wenqiu Zhu 《Computers, Materials & Continua》 SCIE EI 2024年第5期2547-2563,共17页
Remote sensing imagery,due to its high altitude,presents inherent challenges characterized by multiple scales,limited target areas,and intricate backgrounds.These inherent traits often lead to increased miss and false... Remote sensing imagery,due to its high altitude,presents inherent challenges characterized by multiple scales,limited target areas,and intricate backgrounds.These inherent traits often lead to increased miss and false detection rates when applying object recognition algorithms tailored for remote sensing imagery.Additionally,these complexities contribute to inaccuracies in target localization and hinder precise target categorization.This paper addresses these challenges by proposing a solution:The YOLO-MFD model(YOLO-MFD:Remote Sensing Image Object Detection withMulti-scale Fusion Dynamic Head).Before presenting our method,we delve into the prevalent issues faced in remote sensing imagery analysis.Specifically,we emphasize the struggles of existing object recognition algorithms in comprehensively capturing critical image features amidst varying scales and complex backgrounds.To resolve these issues,we introduce a novel approach.First,we propose the implementation of a lightweight multi-scale module called CEF.This module significantly improves the model’s ability to comprehensively capture important image features by merging multi-scale feature information.It effectively addresses the issues of missed detection and mistaken alarms that are common in remote sensing imagery.Second,an additional layer of small target detection heads is added,and a residual link is established with the higher-level feature extraction module in the backbone section.This allows the model to incorporate shallower information,significantly improving the accuracy of target localization in remotely sensed images.Finally,a dynamic head attentionmechanism is introduced.This allows themodel to exhibit greater flexibility and accuracy in recognizing shapes and targets of different sizes.Consequently,the precision of object detection is significantly improved.The trial results show that the YOLO-MFD model shows improvements of 6.3%,3.5%,and 2.5%over the original YOLOv8 model in Precision,map@0.5 and map@0.5:0.95,separately.These results illustrate the clear advantages of the method. 展开更多
关键词 Object detection YOLOv8 multi-scale attention mechanism dynamic detection head
下载PDF
Transfer learning framework for multi-scale crack type classification with sparse microseismic networks
12
作者 Arnold Yuxuan Xie Bing QLi 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第2期167-178,共12页
Rock fracture mechanisms can be inferred from moment tensors(MT)inverted from microseismic events.However,MT can only be inverted for events whose waveforms are acquired across a network of sensors.This is limiting fo... Rock fracture mechanisms can be inferred from moment tensors(MT)inverted from microseismic events.However,MT can only be inverted for events whose waveforms are acquired across a network of sensors.This is limiting for underground mines where the microseismic stations often lack azimuthal coverage.Thus,there is a need for a method to invert fracture mechanisms using waveforms acquired by a sparse microseismic network.Here,we present a novel,multi-scale framework to classify whether a rock crack contracts or dilates based on a single waveform.The framework consists of a deep learning model that is initially trained on 2400000+manually labelled field-scale seismic and microseismic waveforms acquired across 692 stations.Transfer learning is then applied to fine-tune the model on 300000+MT-labelled labscale acoustic emission waveforms from 39 individual experiments instrumented with different sensor layouts,loading,and rock types in training.The optimal model achieves over 86%F-score on unseen waveforms at both the lab-and field-scale.This model outperforms existing empirical methods in classification of rock fracture mechanisms monitored by a sparse microseismic network.This facilitates rapid assessment of,and early warning against,various rock engineering hazard such as induced earthquakes and rock bursts. 展开更多
关键词 multi-scale Fracture processes Microseismic Acoustic emission Source mechanism Deep learning
下载PDF
多功能康复轮椅早期离床锻炼联合渐进性抗阻运动对经内固定术治疗股骨粗隆间骨折患者Harris评分及断骨愈合的影响
13
作者 张志芳 桂飞飞 郝婷婷 《哈尔滨医药》 2024年第6期88-91,共4页
目的 探究多功能康复轮椅早期离床锻炼联合渐进性抗阻运动对经内固定术治疗股骨粗隆间骨折(IFF)的临床效果。方法 选取114例IFF患者,两组均行经内固定术治疗,随机分为对照组(n=57)、联合组(n=57)。对照组给予渐进性抗阻运动,联合组在此... 目的 探究多功能康复轮椅早期离床锻炼联合渐进性抗阻运动对经内固定术治疗股骨粗隆间骨折(IFF)的临床效果。方法 选取114例IFF患者,两组均行经内固定术治疗,随机分为对照组(n=57)、联合组(n=57)。对照组给予渐进性抗阻运动,联合组在此基础上给予多功能康复轮椅早期离床锻炼动。比较两组临床疗效、Barthel指数、髋关节功能评分(Harris)、疼痛视觉模拟评分(VAS)、生活质量综合评定量表(GQOLI-74)评分、骨折愈合情况、骨折愈合因子[转化生长因子-β(TGF-β1)、TGF-β2、胰岛素样生长因子-1(IGF-1)]及并发症发生情况。结果 联合组临床总有效率92.98%高于对照组78.95%(P<0.05);干预1个月后、3个月后联合组VAS评分低于对照组,Barthel指数、Harris评分、GQOLI-74评分高于对照组(P<0.05);干预1个月后、3个月后联合组股骨头局部骨密度、平均骨密度、屈曲肌群和伸直肌肌力高于对照组(P<0.05);干预3个月后联合组TGF-β1、TGF-β2、IGF-1高于对照组(P<0.05);联合组并发症发生率(7.02%)低于对照组(22.81%)(P<0.05)。结论 多功能康复轮椅早期离床锻炼与渐进性抗阻运动联合治疗IFF患者术后效果良好,可改善髋关节功能、促进骨折愈合能力,有助于提高患者生活质量、降低并发症发生率。 展开更多
关键词 多功能康复轮椅 锻炼 渐进性抗阻运动 经内固定术 股骨粗隆间骨折 harris评分 愈合
下载PDF
MSC-YOLO:Improved YOLOv7 Based on Multi-Scale Spatial Context for Small Object Detection in UAV-View
14
作者 Xiangyan Tang Chengchun Ruan +2 位作者 Xiulai Li Binbin Li Cebin Fu 《Computers, Materials & Continua》 SCIE EI 2024年第4期983-1003,共21页
Accurately identifying small objects in high-resolution aerial images presents a complex and crucial task in thefield of small object detection on unmanned aerial vehicles(UAVs).This task is challenging due to variati... Accurately identifying small objects in high-resolution aerial images presents a complex and crucial task in thefield of small object detection on unmanned aerial vehicles(UAVs).This task is challenging due to variations inUAV flight altitude,differences in object scales,as well as factors like flight speed and motion blur.To enhancethe detection efficacy of small targets in drone aerial imagery,we propose an enhanced You Only Look Onceversion 7(YOLOv7)algorithm based on multi-scale spatial context.We build the MSC-YOLO model,whichincorporates an additional prediction head,denoted as P2,to improve adaptability for small objects.We replaceconventional downsampling with a Spatial-to-Depth Convolutional Combination(CSPDC)module to mitigatethe loss of intricate feature details related to small objects.Furthermore,we propose a Spatial Context Pyramidwith Multi-Scale Attention(SCPMA)module,which captures spatial and channel-dependent features of smalltargets acrossmultiple scales.This module enhances the perception of spatial contextual features and the utilizationof multiscale feature information.On the Visdrone2023 and UAVDT datasets,MSC-YOLO achieves remarkableresults,outperforming the baseline method YOLOv7 by 3.0%in terms ofmean average precision(mAP).The MSCYOLOalgorithm proposed in this paper has demonstrated satisfactory performance in detecting small targets inUAV aerial photography,providing strong support for practical applications. 展开更多
关键词 Small object detection YOLOv7 multi-scale attention spatial context
下载PDF
Multi-scale Modeling and Finite Element Analyses of Thermal Conductivity of 3D C/SiC Composites Fabricating by Flexible-Oriented Woven Process
15
作者 Zheng Sun Zhongde Shan +5 位作者 Hao Huang Dong Wang Wang Wang Jiale Liu Chenchen Tan Chaozhong Chen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第3期275-288,共14页
Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale pr... Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC composites.An entirely new process is introduced to weave the preform with three-dimensional orthogonal architecture.The 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary conditions.Three RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the microscale.Besides,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix models.The prediction results at the mesoscale correspond closely to the experimental values.The effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into consideration.The multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures. 展开更多
关键词 3D C/SiC composites Finite element analyses multi-scale modeling Thermal conductivity
下载PDF
基于Harris的遗传粒子滤波及其在车牌跟踪的应用
16
作者 肖宇麒 杨帆 +1 位作者 林华 刘建树 《池州学院学报》 2024年第3期28-33,共6页
为了有效解决传统粒子滤波算法所存在的种群多样性衰减问题,消除由此而带来的算法效率、精度下降的弊端,该研究提出利用遗传算法的交叉和变异遗传操作算子来优化其重采样过程。具体而言,在重采样后,对样本集中各个样本粒子依照适应度值... 为了有效解决传统粒子滤波算法所存在的种群多样性衰减问题,消除由此而带来的算法效率、精度下降的弊端,该研究提出利用遗传算法的交叉和变异遗传操作算子来优化其重采样过程。具体而言,在重采样后,对样本集中各个样本粒子依照适应度值排列顺序,再将适应度低于平均值的样本剔除,同时从留下的适应度较优的粒子中随机地选取同等数量样本用于对应补充被剔除样本,再引入遗传算法的遗传操作对粒子进行交叉、变异操作,来完成样本集的更新。同时考虑到传统视觉目标跟踪常用的灰度和颜色直方图特征极易受到背景颜色干扰、对光照变化极为敏感和计算量也较大等问题,提出引入具有容易提取、运算量小、抗旋转或倾斜角影响等优势的Harris特征,配合遗传粒子滤波跟踪框架,得到了一种鲁棒性较高的跟踪算法。将所提出的基于Harris特征的遗传粒子滤波跟踪器应用于高速公路上的车辆车牌定位,应用实验的结果表明经过遗传操作改进的使用Harris角点检测特征的粒子滤波算法精度、数值稳定性都得到了提高,在目标快速移动、光线和背景剧烈变化等场景都能够实现对目标车牌的有效跟踪。 展开更多
关键词 粒子滤波 机器视觉 车牌跟踪 harris角点检测
下载PDF
Contour Detection Algorithm forαPhase Structure of TB6 Titanium Alloy fused with Multi-Scale Fretting Features
17
作者 Fei He Yan Dou +1 位作者 Xiaoying Zhang Lele Zhang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第5期499-509,共11页
Aiming at the problems of inaccuracy in detecting theαphase contour of TB6 titanium alloy.By combining computer vision technology with human vision mechanisms,the spatial characteristics of theαphase can be simulate... Aiming at the problems of inaccuracy in detecting theαphase contour of TB6 titanium alloy.By combining computer vision technology with human vision mechanisms,the spatial characteristics of theαphase can be simulated to obtain the contour accurately.Therefore,an algorithm forαphase contour detection of TB6 titanium alloy fused with multi-scale fretting features is proposed.Firstly,through the response of the classical receptive field model based on fretting and the suppression of new non-classical receptive field model based on fretting,the information maps of theαphase contour of the TB6 titanium alloy at different scales are obtained;then the information map of the smallest scale contour is used as a benchmark,the neighborhood is constructed to judge the deviation of other scale contour information,and the corresponding weight value is calculated;finally,Gaussian function is used to weight and fuse the deviation information,and the contour detection result of TB6 titanium alloyαphase is obtained.In the Visual Studio 2013 environment,484 metallographic images with different temperatures,strain rates,and magnifications were tested.The results show that the performance evaluation F value of the proposed algorithm is 0.915,which can effectively improve the accuracy ofαphase contour detection of TB6 titanium alloy. 展开更多
关键词 TB6 titanium alloyαphase multi-scale fretting features Contour detection
下载PDF
Few-shot image recognition based on multi-scale features prototypical network
18
作者 LIU Jiatong DUAN Yong 《High Technology Letters》 EI CAS 2024年第3期280-289,共10页
In order to improve the models capability in expressing features during few-shot learning,a multi-scale features prototypical network(MS-PN)algorithm is proposed.The metric learning algo-rithm is employed to extract i... In order to improve the models capability in expressing features during few-shot learning,a multi-scale features prototypical network(MS-PN)algorithm is proposed.The metric learning algo-rithm is employed to extract image features and project them into a feature space,thus evaluating the similarity between samples based on their relative distances within the metric space.To sufficiently extract feature information from limited sample data and mitigate the impact of constrained data vol-ume,a multi-scale feature extraction network is presented to capture data features at various scales during the process of image feature extraction.Additionally,the position of the prototype is fine-tuned by assigning weights to data points to mitigate the influence of outliers on the experiment.The loss function integrates contrastive loss and label-smoothing to bring similar data points closer and separate dissimilar data points within the metric space.Experimental evaluations are conducted on small-sample datasets mini-ImageNet and CUB200-2011.The method in this paper can achieve higher classification accuracy.Specifically,in the 5-way 1-shot experiment,classification accuracy reaches 50.13%and 66.79%respectively on these two datasets.Moreover,in the 5-way 5-shot ex-periment,accuracy of 66.79%and 85.91%are observed,respectively. 展开更多
关键词 few-shot learning multi-scale feature prototypical network channel attention label-smoothing
下载PDF
Improved multi-scale inverse bottleneck residual network based on triplet parallel attention for apple leaf disease identification
19
作者 Lei Tang Jizheng Yi Xiaoyao Li 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第3期901-922,共22页
Accurate diagnosis of apple leaf diseases is crucial for improving the quality of apple production and promoting the development of the apple industry. However, apple leaf diseases do not differ significantly from ima... Accurate diagnosis of apple leaf diseases is crucial for improving the quality of apple production and promoting the development of the apple industry. However, apple leaf diseases do not differ significantly from image texture and structural information. The difficulties in disease feature extraction in complex backgrounds slow the related research progress. To address the problems, this paper proposes an improved multi-scale inverse bottleneck residual network model based on a triplet parallel attention mechanism, which is built upon ResNet-50, while improving and combining the inception module and ResNext inverse bottleneck blocks, to recognize seven types of apple leaf(including six diseases of alternaria leaf spot, brown spot, grey spot, mosaic, rust, scab, and one healthy). First, the 3×3 convolutions in some of the residual modules are replaced by multi-scale residual convolutions, the convolution kernels of different sizes contained in each branch of the multi-scale convolution are applied to extract feature maps of different sizes, and the outputs of these branches are multi-scale fused by summing to enrich the output features of the images. Second, the global layer-wise dynamic coordinated inverse bottleneck structure is used to reduce the network feature loss. The inverse bottleneck structure makes the image information less lossy when transforming from different dimensional feature spaces. The fusion of multi-scale and layer-wise dynamic coordinated inverse bottlenecks makes the model effectively balances computational efficiency and feature representation capability, and more robust with a combination of horizontal and vertical features in the fine identification of apple leaf diseases. Finally, after each improved module, a triplet parallel attention module is integrated with cross-dimensional interactions among channels through rotations and residual transformations, which improves the parallel search efficiency of important features and the recognition rate of the network with relatively small computational costs while the dimensional dependencies are improved. To verify the validity of the model in this paper, we uniformly enhance apple leaf disease images screened from the public data sets of Plant Village, Baidu Flying Paddle, and the Internet. The final processed image count is 14,000. The ablation study, pre-processing comparison, and method comparison are conducted on the processed datasets. The experimental results demonstrate that the proposed method reaches 98.73% accuracy on the adopted datasets, which is 1.82% higher than the classical ResNet-50 model, and 0.29% better than the apple leaf disease datasets before preprocessing. It also achieves competitive results in apple leaf disease identification compared to some state-ofthe-art methods. 展开更多
关键词 multi-scale module inverse bottleneck structure triplet parallel attention apple leaf disease
下载PDF
Multi-Scale Mixed Attention Tea Shoot Instance Segmentation Model
20
作者 Dongmei Chen Peipei Cao +5 位作者 Lijie Yan Huidong Chen Jia Lin Xin Li Lin Yuan Kaihua Wu 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第2期261-275,共15页
Tea leaf picking is a crucial stage in tea production that directly influences the quality and value of the tea.Traditional tea-picking machines may compromise the quality of the tea leaves.High-quality teas are often... Tea leaf picking is a crucial stage in tea production that directly influences the quality and value of the tea.Traditional tea-picking machines may compromise the quality of the tea leaves.High-quality teas are often handpicked and need more delicate operations in intelligent picking machines.Compared with traditional image processing techniques,deep learning models have stronger feature extraction capabilities,and better generalization and are more suitable for practical tea shoot harvesting.However,current research mostly focuses on shoot detection and cannot directly accomplish end-to-end shoot segmentation tasks.We propose a tea shoot instance segmentation model based on multi-scale mixed attention(Mask2FusionNet)using a dataset from the tea garden in Hangzhou.We further analyzed the characteristics of the tea shoot dataset,where the proportion of small to medium-sized targets is 89.9%.Our algorithm is compared with several mainstream object segmentation algorithms,and the results demonstrate that our model achieves an accuracy of 82%in recognizing the tea shoots,showing a better performance compared to other models.Through ablation experiments,we found that ResNet50,PointRend strategy,and the Feature Pyramid Network(FPN)architecture can improve performance by 1.6%,1.4%,and 2.4%,respectively.These experiments demonstrated that our proposed multi-scale and point selection strategy optimizes the feature extraction capability for overlapping small targets.The results indicate that the proposed Mask2FusionNet model can perform the shoot segmentation in unstructured environments,realizing the individual distinction of tea shoots,and complete extraction of the shoot edge contours with a segmentation accuracy of 82.0%.The research results can provide algorithmic support for the segmentation and intelligent harvesting of premium tea shoots at different scales. 展开更多
关键词 Tea shoots attention mechanism multi-scale feature extraction instance segmentation deep learning
下载PDF
上一页 1 2 159 下一页 到第
使用帮助 返回顶部