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不同运动项目运动员髋关节屈伸肌群横断面积与力矩特征的相关研究 被引量:5
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作者 宋吉锐 张海平 《沈阳体育学院学报》 2004年第4期480-482,485,共4页
通过对足球、速度滑冰运动员髋关节屈伸肌群横断面积及力学相关指标的测定,探讨不同运动项目的运动员髋关节屈伸肌群形态特征与肌肉收缩效应的特点以及两者间的内在规律,为运动员训练水平的评估及科学选材等提供理论指导。肌肉横断面积... 通过对足球、速度滑冰运动员髋关节屈伸肌群横断面积及力学相关指标的测定,探讨不同运动项目的运动员髋关节屈伸肌群形态特征与肌肉收缩效应的特点以及两者间的内在规律,为运动员训练水平的评估及科学选材等提供理论指导。肌肉横断面积采用螺旋CT进行断层扫描,影像分析采用MoticImagesAdvanced3 0测试系统软件,力量测试采用美国Cybex Norm等速测力系统,数据处理采用SPSS 8 0软件。结果表明:足球运动员大腿肌肉横断面积大于速滑运动员,差异主要表现在股四头肌和股后肌群。在相同测试速度下,足球与速度运动员髋关节屈伸时,左右两腿肌肉收缩力量无明显差异。但不同项目间,同一肌群在不同关节运动,不同速度下,则表现出肌肉力量的明显不同。髋关节屈伸运动时,股四头肌与股后肌群横断面积与力矩的相关程度,足球以屈为明显,速滑以右伸为明显。 展开更多
关键词 运动项目 运动员 髋关节 屈伸肌群 横断面积 力矩特征 形态特征 肌肉收缩效应
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基于快速轮廓转动力矩特征的激光主动成像目标识别 被引量:5
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作者 王灿进 孙涛 李正炜 《中国光学》 EI CAS CSCD 2015年第5期775-784,共10页
针对激光主动成像的图像特性,提出一种基于快速轮廓转动力矩的目标识别方法。将转动力矩的概念引入目标识别中,提出的快速轮廓转动力矩特征(FCTF)不仅包含了轮廓的尺寸、位置、规则度以及目标的亮暗等信息,同时对于旋转、尺度缩放等变... 针对激光主动成像的图像特性,提出一种基于快速轮廓转动力矩的目标识别方法。将转动力矩的概念引入目标识别中,提出的快速轮廓转动力矩特征(FCTF)不仅包含了轮廓的尺寸、位置、规则度以及目标的亮暗等信息,同时对于旋转、尺度缩放等变换具有不变性。采用转动力矩的快速计算方法,提高了识别算法的计算效率。识别算法首先使用最大稳定极值区域(MSER)算法检测出目标特征区域,并将其变换为圆形区域,然后结合快速转动力矩特征算法提取出目标区域的局部不变特征,最后输入训练好的支持向量机分类器进行识别。实验结果表明相比于已有的激光主动成像目标识别方法,所提算法对于旋转、仿射变换均具有更高的识别率,同时单帧平均运算时间为9.68 ms,满足激光主动成像目标识别系统实时性的要求。 展开更多
关键词 激光主动成像 目标识别 最大稳定极值区域 快速轮廓转动力矩特征 支持向量机
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自适应搜索的快速分形图像编码算法
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作者 李高平 《小型微型计算机系统》 CSCD 北大核心 2010年第4期770-774,共5页
为了改进全搜索分形编码过程匹配耗时长而导致难以实用的缺点,新定义了规范块灰度值力矩来反映图像块的特征,根据匹配均方根误差与规范块灰度值力矩间的关系,建立一个预先剔除条件来排除许多不大可能匹配range块的domain块.对一个待编码... 为了改进全搜索分形编码过程匹配耗时长而导致难以实用的缺点,新定义了规范块灰度值力矩来反映图像块的特征,根据匹配均方根误差与规范块灰度值力矩间的关系,建立一个预先剔除条件来排除许多不大可能匹配range块的domain块.对一个待编码range块,仅在与该range块灰度值力矩数值最接近的domain块的自适应搜索邻域范围内找它的最佳匹配块.仿真结果表明,与全搜索分形图像编码算法相比,三幅测试图像在重建图像质量更好的情况下,能够平均加快它的编码速度58倍. 展开更多
关键词 分形 图像编码 灰度值力矩特征 自适应搜索 剔除条件
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Image Zernike Moments Shape Feature Evaluation Based on Image Reconstruction 被引量:2
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作者 LIU Maofu HE Yanxiang YE Bin 《Geo-Spatial Information Science》 2007年第3期191-195,共5页
The evaluation approach to the accuracy of the image feature descriptors plays an important role in image feature extraction. We point out that the image shape feature can be described by the Zernike moments set while... The evaluation approach to the accuracy of the image feature descriptors plays an important role in image feature extraction. We point out that the image shape feature can be described by the Zernike moments set while briefly introducing the basic concept of the Zernike moment. After talking about the image reconstruction technique based on the inverse transformation of Zernike moment, the evaluation approach to the accuracy of the Zernike moments shape feature via the dissimilarity degree and the reconstruction ratio between the original image and the reconstructed image is proposed. The experiment results demonstrate the feasibility of this evaluation approach to image Zernike moments shape feature. 展开更多
关键词 feature evaluation Zernike moment image reconstruction reconstruction ratio
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Thermodynamic properties and constitutive relations of crystals at finite temperature 被引量:6
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作者 TANG QiHeng WANG TzuChiang +1 位作者 SHANG BaoShuang LIU Feng 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第6期918-926,共9页
The dynamics equation for each individual atom is established directly around the equilibrium state of the system of N atoms based on the inter-atomic potential energy of EAM model.Using the theory of lattice dynamics... The dynamics equation for each individual atom is established directly around the equilibrium state of the system of N atoms based on the inter-atomic potential energy of EAM model.Using the theory of lattice dynamics and periodical boundary condition,the 3N×3N stiffness matrix in eigen equations of vibration frequencies for a parallelepiped crystal is reduced to a 3n×3n matrix of eigen equations of vibration frequencies for a unit lattice.The constitutive relation of the crystal at finite temperature is extracted based on the quantum-mechanical principle.The thermodynamic properties and the stress-strain relationships of crystal Cu with large plastic deformation at different temperatures are calculated,the calculation results agree well with experimental data. 展开更多
关键词 lattice wave theory molecular dynamics thermodynamic properties constitutive model interatomic potential
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Finite-time adaptive consensus of a class of multi-agent systems 被引量:17
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作者 LIU KeXin WU LuLu +1 位作者 Lü JinHu ZHU HengHui 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第1期22-32,共11页
Multi-agent systems(MASs) are ubiquitous in natural and artificial systems. This paper aims to establish the finite-time adaptive consensus criterion for a class of MASs with nonlinear dynamics. Traditionally, the fin... Multi-agent systems(MASs) are ubiquitous in natural and artificial systems. This paper aims to establish the finite-time adaptive consensus criterion for a class of MASs with nonlinear dynamics. Traditionally, the finite-time consensus criterion is often established based on the prior information on Lipschitz constants and the eigenvalues of Laplacian matrix. However, it is difficult to acquire the above prior information for most real-world engineering systems. To overcome the above difficulty, this paper develops the finite-time consensus criteria for a class of MASs with nonlinear dynamics via adaptive technique. In detail, we design the finite-time distributed node-based and edge-based adaptive consensus protocols for a class of MASs with fixed and switching topologies. Numerical simulations are also given to validate the proposed finite-time adaptive consensus criterion. 展开更多
关键词 Multi-agent systems adaptive control finite-time consensus switching topology
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