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基于互信息与边缘互距离的医学图像配准 被引量:1
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作者 胡顺波 刘常春 《计算机工程与应用》 CSCD 北大核心 2008年第6期36-38,共3页
提出了一种基于互信息与边缘互距离信息的医学图像配准新测度。该种测度既利用了待配准图像间的灰度互信息,又利用了图像边缘间的互距离均值和互距离方差空间信息,从而改进了互信息测度。实验证明这种测度得到的配准参数曲线光滑且峰值... 提出了一种基于互信息与边缘互距离信息的医学图像配准新测度。该种测度既利用了待配准图像间的灰度互信息,又利用了图像边缘间的互距离均值和互距离方差空间信息,从而改进了互信息测度。实验证明这种测度得到的配准参数曲线光滑且峰值尖锐,收敛范围宽,对图像大小有更强的鲁棒性,在图像互信息值一样的情况下,仍有辨识能力。 展开更多
关键词 信息 边缘互距离 医学图像配准
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频率步进信号距离像互相关精确测速算法 被引量:5
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作者 李磊 任丽香 +2 位作者 毛二可 何佩琨 赵保军 《北京理工大学学报》 EI CAS CSCD 北大核心 2011年第6期708-712,726,共6页
针对距离像互相关算法可以实现频率步进信号自测速但测速精度有限这一问题,通过对互相关输出包络和相位的分析,提出了距离像互相关波形分析法和距离像互相关峰值相位法2种测速算法,结合这2种方法提出了一种频率步进信号距离像互相关精... 针对距离像互相关算法可以实现频率步进信号自测速但测速精度有限这一问题,通过对互相关输出包络和相位的分析,提出了距离像互相关波形分析法和距离像互相关峰值相位法2种测速算法,结合这2种方法提出了一种频率步进信号距离像互相关精确测速算法,该算法的测速精度可以与多普勒测速相比拟,不仅能满足频率步进信号速度补偿的要求,还可以实现微动目标的测量.仿真结果验证了该算法的有效性. 展开更多
关键词 速度估计 频率步进信号 距离相关 波形分析法 微动测量
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基于互近邻相对距离的最小生成树聚类算法 被引量:2
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作者 程汝峰 刘奕志 梁永全 《郑州大学学报(理学版)》 CAS 北大核心 2017年第3期20-27,共8页
针对互近邻距离的不足,提出了互近邻相对距离的概念,同时设计实现了一种新的最小生成树聚类算法.针对某些数据的不平衡问题,提出了兼容不平衡数据的最小生成树分割方法.算法设计简单,易于实现.实验结果表明,该算法能够聚类任意形状数据... 针对互近邻距离的不足,提出了互近邻相对距离的概念,同时设计实现了一种新的最小生成树聚类算法.针对某些数据的不平衡问题,提出了兼容不平衡数据的最小生成树分割方法.算法设计简单,易于实现.实验结果表明,该算法能够聚类任意形状数据和兼容处理不均衡数据.对于具有良好几何形状的数据,该算法能够达到非常好的聚类效果,总体性能优于其他算法. 展开更多
关键词 聚类 近邻相对距离 最小生成树 不平衡数据
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低信噪比条件下基于距离像互相关的相推测速方法 被引量:3
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作者 李文吉 任丽香 +1 位作者 张康 毛二可 《信号处理》 CSCD 北大核心 2021年第7期1125-1132,共8页
相推测速技术可以实现相位量级的测量精度,在微动测量和目标识别领域有着极大的应用前景。该方法对信噪比要求较高,且存在准确提取相位和解相位模糊两大难点。本文提出了针对低信噪比条件下的相推测速实现方法。首先,建立了宽带线性调... 相推测速技术可以实现相位量级的测量精度,在微动测量和目标识别领域有着极大的应用前景。该方法对信噪比要求较高,且存在准确提取相位和解相位模糊两大难点。本文提出了针对低信噪比条件下的相推测速实现方法。首先,建立了宽带线性调频信号去斜处理的回波模型;然后推导了相邻帧距离像互相关结果,并分析了距离像互相关输出的峰值点相位;进而为了提高相推测速在低信噪比条件下的适用性,提出了对距离像互相关结果沿慢时间维进行积累的方法,该方法可以重新提取峰值点相位,以及获得目标速度的粗估计值进而辅助后续的解相位模糊。此外,为抑制噪声对相位提取精度的影响,本文提出根据相位的频谱特性设计滤波器的方法,进一步提高相推测速的精度。最后通过仿真和实测数据验证了所提方法的正确性及其在低信噪比条件下的适用性。 展开更多
关键词 距离相关 相推测速 滤波器设计 低信噪比
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基于暂态信号距离辨识的MMC-HVDC线路保护方案 被引量:1
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作者 吕承 邰能灵 +1 位作者 郑晓冬 查凯文 《水电能源科学》 北大核心 2018年第8期185-188,共4页
针对柔性直流线路保护的主要技术难点直流故障的可靠识别和快速隔离,分析了基于模块化多电平换流器(MMC)的柔性直流输电线路故障暂态量变化特征,发现线路内部故障时直流线路两端的电流量、电压量变化特征与区外故障时有较大差异。并通... 针对柔性直流线路保护的主要技术难点直流故障的可靠识别和快速隔离,分析了基于模块化多电平换流器(MMC)的柔性直流输电线路故障暂态量变化特征,发现线路内部故障时直流线路两端的电流量、电压量变化特征与区外故障时有较大差异。并通过暂态信号距离辨识得出互距离度构成线路保护判据。仿真验证表明,该方案原理简单、可靠性高,且不受系统参数及干扰的影响。 展开更多
关键词 模块化多电平柔性直流输电 线路故障 暂态信号 距离辨识 互距离
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无线电引信互扰效应规律研究 被引量:1
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作者 熊久良 武占成 +2 位作者 孙永卫 高乐南 谢鹏浩 《电波科学学报》 EI CSCD 北大核心 2015年第5期903-909,共7页
针对部队实弹打靶中某型引信早炸率过高的问题,提出了引信互扰效应试验方法,开展了引信互扰效应试验,分析了该型引信的互扰效应规律,并确定了其失效机理.试验结果表明:引信相对速度、相对姿态、相对高度、辐射能量、辐射频率以及加电方... 针对部队实弹打靶中某型引信早炸率过高的问题,提出了引信互扰效应试验方法,开展了引信互扰效应试验,分析了该型引信的互扰效应规律,并确定了其失效机理.试验结果表明:引信相对速度、相对姿态、相对高度、辐射能量、辐射频率以及加电方式都会对引信临界互扰距离产生影响.引信互扰效应机理为:引信靠近过程中,由于辐射能量及辐射频率接近而产生频率牵引,导致检波电压信号波动,从而推动引信执行电路误动作. 展开更多
关键词 引信 扰效应 临界距离 失效机理 频率牵引
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一种新的短帧交织器设计 被引量:6
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作者 刘文明 朱光喜 何业军 《通信学报》 EI CSCD 北大核心 2005年第11期62-67,共6页
分析了交织器的自交织距离与互交织距离对译码性能的影响,建立了交织距离的目标函数,提出了交织器优化设计的设计准则。在此基础上,给出了一种线性迭代的交织器设计方法,仿真结果表明该交织器具有优良的性能。
关键词 TURBO编码 自交织距离 交织距离 线性迭代序列
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Power interconnected system clustering with advanced fuzzy C-mean algorithm 被引量:6
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作者 王洪梅 KIM Jae-Hyung +2 位作者 JUNG Dong-Yean LEE Sang-Min LEE Sang-Hyuk 《Journal of Central South University》 SCIE EI CAS 2011年第1期190-195,共6页
An advanced fuzzy C-mean (FCM) algorithm was proposed for the efficient regional clustering of multi-nodes interconnected systems. Due to various locational prices and regional coherencies for each node and point, m... An advanced fuzzy C-mean (FCM) algorithm was proposed for the efficient regional clustering of multi-nodes interconnected systems. Due to various locational prices and regional coherencies for each node and point, modified similarity measure was considered to gather nodes having similar characteristics. The similarity measure was needed to contain locafi0nal prices as well as regional coherency. In order to consider the two properties simultaneously, distance measure of fuzzy C-mean algorithm had to be modified. Regional clustering algorithm for interconnected power systems was designed based on the modified fuzzy C-mean algorithm. The proposed algorithm produces proper classification for the interconnected power system and the results are demonstrated in the example of IEEE 39-bus interconnected electricity system. 展开更多
关键词 fuzzy C-mean similarity measure distance measure interconnected system CLUSTERING
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一种新型的Turbo码短帧交织器的设计
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作者 马丽芳 《河池学院学报》 2017年第2期106-111,共6页
交织器是Turbo码的关键组成部分,也是影响其性能的关键因素。Turbo码在低信噪比条件下的性能主要取决于其距离谱,而影响距离谱的一个关键因素就是交织器的设计。文章提出了一种新型的Turbo码短帧交织器的设计方法。这种交织器是通过确... 交织器是Turbo码的关键组成部分,也是影响其性能的关键因素。Turbo码在低信噪比条件下的性能主要取决于其距离谱,而影响距离谱的一个关键因素就是交织器的设计。文章提出了一种新型的Turbo码短帧交织器的设计方法。这种交织器是通过确定每个相邻信息比特位之间的距离和首位信息比特的位置来设计,保证最小的互交织距离足够大且能够自由调节自交织距离。相比其他的交织器,其在突发信道有更好的性能,并且实现简单。 展开更多
关键词 交织器 TURBO码 自交织距离 交织距离
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基于改进核函数的支持向量机时间序列数据分类 被引量:3
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作者 李翔宇 李瑞兴 曾燕清 《信阳农林学院学报》 2021年第1期121-126,共6页
针对传统支持向量机(support vector machine,SVM)对时间序列数据分类,仅通过样本在空间中的几何距离判别样本的类别,提出了一种基于改进核函数的支持向量机算法(SVM_IK,SVM with improved kernel function)。该算法计算样本与空间基数... 针对传统支持向量机(support vector machine,SVM)对时间序列数据分类,仅通过样本在空间中的几何距离判别样本的类别,提出了一种基于改进核函数的支持向量机算法(SVM_IK,SVM with improved kernel function)。该算法计算样本与空间基数据的时间序列互相关距离,将样本数据映射到新的特征空间中,实现对线性核函数改进,最终根据改进的线性核函数SVM算法对样本数据进行分类。算法通过25组UCR数据集的验证,实验结果显示与1-NN算法和传统SVM算法相比,SVM_IK算法对时间序列数据具有较好的分类效果。 展开更多
关键词 时间序列相关距离 SVM 时间序列数据 分类
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INTERANNUAL VARIATION CHARACTERISTICS OF EAST HEMISPHERIC CROSS-EQUATORIAL FLOW AND ITS CONCURRENT RELATIONSHIPS WITH TEMPERATURE AND RAINFALL IN CHINA
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作者 雷小春 杨修群 《Journal of Tropical Meteorology》 SCIE 2008年第2期97-100,共4页
The NCEP/NCAR global reanalysis data were used to analyze the interannual variation characteristics of the cross-equatorial flow (CEF) and its concurrent relationships with temperature and rainfall in China. The resul... The NCEP/NCAR global reanalysis data were used to analyze the interannual variation characteristics of the cross-equatorial flow (CEF) and its concurrent relationships with temperature and rainfall in China. The results indicated that CEF changes more in summer than in winter. As the main flow channel in summer, the Somali CEF changes in a way that does not markedly influence the changes in the CEF total except for winter. The summer CEF total has two sudden increases and one sudden decrease during the last century while the winter total has just one decrease. Long-period data show that the correlation between CEF and summer rainfall in China is not very significant, but is different before and after the 1970s, which is due to CEF's close links with the East Asia summer monsoon. Winter CEF's correlation with concurrent winter temperature in northern and southern China varies with the relationship between CEF and sea-level pressure in different areas. 展开更多
关键词 cross-equatorial flow (CEF) interannual variation characteristics RAINFALL TEMPERATURE correlation
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A growing social networks model of physical objects in IoT
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作者 Li Ali Zhai Yun 《High Technology Letters》 EI CAS 2018年第2期163-168,共6页
In Internet of Things (IoT) cial networks of physical objects , physical objects can build their own social networks. How do so- generate, and what characteristics do the social networks have. In order to solve thes... In Internet of Things (IoT) cial networks of physical objects , physical objects can build their own social networks. How do so- generate, and what characteristics do the social networks have. In order to solve these problems, according to the interaction of physical objects in IoT, this paper presents a growing social network model of physical objects and researches the attachment mecha- nism of the model that includes three modes, physical distance, social distance and preference. Through the simulation realizations of the model, the characteristics (e. g. degree distribution, com- munity structure) of social network are analyzed. The model can forecast the growth of social networks of physical object in IoT and simulate social networks of physical objects in the large scale IoT. 展开更多
关键词 Internet of Things(IoT) social networks physical objects
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Middle range wireless power transfer systems with multiple resonators 被引量:1
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作者 陈新 张桂香 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2127-2136,共10页
The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, re... The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, resistance, parasitic capacitance, mutual inductance and S-parameters of coils & resonators were analyzed. The impedance matching method was used to optimize load power and transmission efficiency of the multi-resonator WPT system, and the impedance matching method was realized through adjusting the distances between the coils and resonators. Experiments show that the impedance matching method can effectively improve load power and transmission efficiency for middle range wireless power transfer systems with multiple resonators, at distances up to 3 times the coil radius with efficiency more than 70% and load power also close to 3.5 W. 展开更多
关键词 wireless power transfer middle range multiple resonators S-PARAMETERS two-port network impedance matching
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PREVIOUS CONVECTION ANOMALY IN AUTUMN AND WINTER ASSOCIATED WITH THE GENERAL CIRCULATION OVER EAST ASIA IN WINTER AND SPRING AND APRIL PRECIPITATION IN SHANDONG
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作者 胡桂芳 张璇 顾伟宗 《Journal of Tropical Meteorology》 SCIE 2008年第2期133-136,共4页
Using OLR and 850 hPa and 200 hPa wind fields data (1979 - 2006), this paper diagnoses the characteristics of convection over the tropical area in preceding autumns and winters in association with April precipitation ... Using OLR and 850 hPa and 200 hPa wind fields data (1979 - 2006), this paper diagnoses the characteristics of convection over the tropical area in preceding autumns and winters in association with April precipitation anomalies in Shandong province. It is found that preceding convection anomalies over the Western Pacific Warm Pool in December have close relationships with the April precipitation in Shandong. Further analysis of the relationship with the general circulation over the East Asia shows that the convection anomaly over the Western Pacific Warm Pool has close relationships with the Main East Asian Trough, the Hadley cell over East Asia and the Walker cell. The characteristics of East Asian atmospheric circulation anomalies accompanied with stronger (weaker) convection are consistent with those of less (more) April precipitation anomalies in Shandong. Therefore, the convection anomaly over the tropics in December may be an important indicator for April precipitation in Shandong. 展开更多
关键词 convection over the tropics general circulation over East Asia April precipitation in Shandong
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基于改进最大互信息法的MR切片图像配准 被引量:5
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作者 王凌 陈震 +1 位作者 危水根 黄静 《生物医学工程学杂志》 EI CAS CSCD 北大核心 2012年第2期201-205,共5页
医学图像配准是医学图像处理分析的关键步骤,是医学图像融合首先要解决的问题。本研究的主要目的是实现帕金森患者深脑部刺激手术前后MR图像的配准。将互距离引入互信息测度,实现手术前后两组MR切片图像的对应匹配,然后将对应的两组MR... 医学图像配准是医学图像处理分析的关键步骤,是医学图像融合首先要解决的问题。本研究的主要目的是实现帕金森患者深脑部刺激手术前后MR图像的配准。将互距离引入互信息测度,实现手术前后两组MR切片图像的对应匹配,然后将对应的两组MR切片系列重建三维图像,最后用Powell优化算法对重建的三维图像进行配准。通过术前术后MR三维图像的配准,可以定量的分析手术后植入电极和手术前丘脑底核的相对位置关系,从而实现对深脑部刺激手术质量的科学评估。 展开更多
关键词 深脑部刺激手术 互距离 信息 图像配准
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Interaction analyses between tunnel and landslide in mountain area 被引量:6
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作者 ZHANG Zhi-guo ZHAO Qi-hua +1 位作者 XU Chen XU Xiao-yang 《Journal of Mountain Science》 SCIE CSCD 2017年第6期1124-1139,共16页
This paper focuses on the analytical derivation and the numerical simulation analyses to predict the interaction influences between a landslide and a new tunnel in mountain areas. Based on the slip-line theory, the di... This paper focuses on the analytical derivation and the numerical simulation analyses to predict the interaction influences between a landslide and a new tunnel in mountain areas. Based on the slip-line theory, the disturbance range induced by tunneling and the minimum safe distance between the tunnel vault and the sliding belt are obtained in consideration of the mechanical analyses of relaxed rocks over the tunnel opening. The influence factors for the minimum safe crossing distance are conducted,including the tunnel radius, the friction angle of surrounding rocks, the inclination angle of sliding belt,and the friction coefficient of surrounding rocks. Secondly, taking account of the compressive zone and relaxed rocks caused by tunneling, the Sarma method is employed to calculate the safety factor of landslide. Finally, the analytical solutions for interaction between the tunnel and the landslide are compared with a series of numerical simulations, considering the cases for different perpendicular distances between the tunnel vault and the sliding belt. Resultsshow that the distance between the tunnel vault and the slip zone has significant influence on the rock stress and strain. For the case of the minimum crossing distance, a plastic zone in the landslide traversed by tunneling would be formed with rather large range, which seriously threatens the stability of landslide. This work demonstrates that the minimum safe crossing distance obtained from numerical simulation is in a good agreement with that calculated by the proposed analytical solutions. 展开更多
关键词 Tunnel excavation Landslide Safe crossing distance Analytical method Numerical simulation
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Effects of Social Relationships on People's Acceptance of Robots: Using Forms of Language by Robots
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作者 Yunkyung Kiml Sonya Sona Kwak Myung-Suk Kim 《Computer Technology and Application》 2011年第9期724-729,共6页
This study investigated the difference in the levels of people's acceptance of robots by the types of social relationships between humans and robots. In this study, social relationships between a robot and a person w... This study investigated the difference in the levels of people's acceptance of robots by the types of social relationships between humans and robots. In this study, social relationships between a robot and a person were categorized into four types consisted of two in the horizontal of social relationship (intimacy dimension) and two in the vertical of social relationship (status dimension). In dialogue between humans and robots, the types of social relationship were adjusted by forms of language such as calling by name and speech styles. People's acceptance of robots was measured by people's comfortable approach distance to the robot. Participants showed greater acceptance of a robot when the robot called them by their names. In the case of speech style, participants accepted the robot which used honorific speech style without addressing them by their name, while they accepted the robot which used familiar speech style with addressing them by their name. There was an interaction effect between gender and calling by name. 展开更多
关键词 Acceptance of robot robot dialogue human-robot interaction
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基于时空行为规律挖掘的公交乘客分类方法 被引量:5
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作者 陈君 田朝军 +1 位作者 赵清梅 李晓伟 《交通运输工程学报》 EI CSCD 北大核心 2021年第5期274-285,共12页
应用智能公交系统(APTS)提取个体乘客出行信息,构造了公交出行链,研究了基于时空行为规律挖掘(STBRM)的公交乘客分类方法;应用时间序列表征乘客出行时间特征,利用互相关距离(CCD)算法计算了个体乘客出行时间规律;应用带噪声基于密度的... 应用智能公交系统(APTS)提取个体乘客出行信息,构造了公交出行链,研究了基于时空行为规律挖掘(STBRM)的公交乘客分类方法;应用时间序列表征乘客出行时间特征,利用互相关距离(CCD)算法计算了个体乘客出行时间规律;应用带噪声基于密度的空间聚类(DBSCAN)算法,挖掘了个体乘客的出行空间规律;依据出行强度和出行时空规律,将乘客划分为极少出行、时间规律、空间规律、时空规律和不规律等5个群体;以出行天数、类似上车时间数量和类似上车站点数量为聚类指标,应用K-Means++算法将乘客划分为高规律、中规律和低规律3类,比较了本文提出的STBRM方法和K-Means++聚类方法的分类结果,揭示了2种方法分类结果之间的关系。研究结果表明:当时段划分长度取5 min,时间规律性判断阈值取3.0时,利用CCD算法识别时间模式规律乘客的效果最佳,与常用的DBSCAN算法相比,识别率提升了14.64%;增加时间窗长度能够提高时间、空间模式规律判定结果的稳定性;时间窗长度达到3周后,空间模式规律的乘客比例下降趋缓,达到6周后趋于稳定;时间窗长度达到2周后,时间模式规律的乘客比例增长趋缓,达到4周后趋于稳定;时间规律、空间规律和时空规律等3类乘客数量仅占总乘客数量的30.4%,但其出行量占到了总出行量的84.7%,公交依赖度很高,应作为公交机构重点保障的对象;本文提出的STBRM方法与K-Means++聚类方法的分类结果具有较强的关联性,规律性极高或极低的群体高度重合。 展开更多
关键词 智能交通 乘客分类 相关距离 DBSCAN算法 K-Means++算法 时空行为
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SIZE MATTERS:PITCH DIMENSIONS CONSTRAIN INTERACTIVE TEAM BEHAVIOUR IN SOCCER 被引量:1
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作者 FRENCKEN Wouter VAN DER PLAATS Jorrit +1 位作者 VISSCHER Chris LEMMINK Koen 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2013年第1期85-93,共9页
Pitch size varies in official soccer matches and differently sized pitches are adopted for tactical purposes in small-sided training games. Since interactive team behaviour emerges under constraints, the authors evalu... Pitch size varies in official soccer matches and differently sized pitches are adopted for tactical purposes in small-sided training games. Since interactive team behaviour emerges under constraints, the authors evaluate the effect of pitch size (task) manipulations on interactive team behaviour in small-sided soccer games. Four 4-a-side (plus goalkeepers) small-sided games were played: a reference game (30×20 m), length manipulation (24×20 m), width manipulation (30×16 m), and a combina- tion (2× 16 m). Using position data (100Hz), three measures quantifying the teams' interaction were calculated: longitudinal inter-team distance, laterM inter-team distance, and surface area difference. Means and standard deviations, correlations and coupling values were calculated. Running correlations were calculated over a 3-s window to evaluate interaction patterns. As expected, a shorter pitch results in smaller longitudinal inter-team distance, lateral inter-team distance decreased for narrow pitches, and smaller total playing area resulted in decreased surface area. Unanticipated, a crossover effect was present; length and width manipulations also triggered changes in lateral and longitudinal direction respectively. Inter-team distances and surface area difference differed significantly across conditions. Interaction patterns differed across conditions for all measures. So, highly tactically relevant, soccer teams seem to adapt their interactive behaviour according to pitch size in small-sided gaines. 展开更多
关键词 Constraints dynamics performance analysis small-sided games tactics.
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A Classification of Long-Range Interactions between Two Stacks of p& p'-Branes
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作者 欧阳君 吴超 《Communications in Theoretical Physics》 SCIE CAS CSCD 2015年第2期195-208,共14页
We generalize the computations of the long-range interactions between two parallel stacks of branes to various cases when two stacks of branes are not placed parallel to each other. We classify the nature of interacti... We generalize the computations of the long-range interactions between two parallel stacks of branes to various cases when two stacks of branes are not placed parallel to each other. We classify the nature of interaction(repulsive or attractive) for each special case and this classification can be used to justify the nature of long-range interaction between two complicated brane systems such as brane bound states. We will provide explicit examples in this paper to demonstrate this. 展开更多
关键词 long-range interaction effective field theory computation non-parallel branes FLUX
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