Evaluating the contribution of lower extremity kinetics to whole body power output during the power snatch     

Sangwoo Lee  Kyle D. DeRosia  Landon M. Lamie 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(4):554-556

This study evaluated the contribution of lower extremity (hip, knee and ankle) net joint torques (NJT) to whole body power (WBP) output during the power snatch (PS). Ten experienced weightlifters (five males and five females) performed five trials of the PS with 60% of one repetition maximum. Lower extremity NJT and WBP were extracted through a three-dimensional motion analyses and used for data analyses. Pearson correlation coefficients were obtained to observe the relationship between lower extremity NJT and WBP. Multiple-regression (stepwise) analyses was also conducted to evaluate the contribution of lower extremity NJT to WBP during the PS with the hip, knee and ankle NJT being the independent variables. Hip NJT was characterised as a significant positive correlation with WBP (r = 0.47, p < 0.01), while knee NJT showed a significant negative correlation with WBP (r = ?0.34, p < 0.05). A significant inter-correlation was also observed between hip NJT and knee NJT (r = ?0.66, p < 0.01). Hip NJT was identified as a significant contributor to WBP during the PS. Practically, this study suggested that training skills allowing weightlifters to utilise hip extensor muscle action would help to improve WBP during the PS.  相似文献   

复元活血饮抗动物运动性疲劳作用的研究     

王莉  徐小平 《西安体育学院学报》2005,22(6):66-69

通过给实验小鼠灌服复元活血饮口服液,观察其对动物耐力运动、协调运动,对抗性运动及对实验动物RBC(红细胞)、Hb(血红蛋白)、血乳酸含量的影响,发现其疲劳消除作用显著,为进一步在人体推广应用提供实验依据。  相似文献   

Modeling Movie Success When ‘Nobody Knows Anything’: Conditional Stable-Distribution Analysis Of Film Returns     

W.?David?WallsEmail author 《Journal of Cultural Economics》2005,29(3):177-190

In this paper we apply a recently-developed statistical model that explicitly accounts for the extreme uncertainty surrounding film returns. The conditional distribution of box-office returns is analyzed using the stable distribution regression model. The regression coefficients in this model represent what is known about the correlates of film success while at the same time permitting the variance of film success at the box office to be infinite. The empirical analysis shows that the conditional distribution of film returns has infinite variance, and this invalidates statistical inferences from the often-applied least-squares regression model. The estimates of the stable regression confirm some earlier results on the statistics of the movie business and the analysis demonstrates how to model box-office success in the movie business where “nobody knows anything”.  相似文献   

Detection As Multi-Topic Tracking   总被引：1，自引：0，他引：1  

James Allan 《Information Retrieval》2002,5(2-3):139-157

The topic tracking task from TDT is a variant of information filtering tasks that focuses on event-based topics in streams of broadcast news. In this study, we compare tracking to another TDT task, detection, which has the goal of partitioning all arriving news into topics, regardless of whether the topics are of interest to anyone, and even when a new topic appears that had not been previous anticipated. There are clear relationships between the two tasks (under some assumptions, a perfect tracking system could solve the detection problem), but they are evaluated quite differently. We describe the two tasks and discuss their similarities. We show how viewing detection as a form of multi-topic parallel tracking can illuminate the performance tradeoffs of detection over tracking.  相似文献   

广播电视报的时代功能     

李效文 《贵阳金筑大学学报》2004,(1):26-28

广播电视报只有做好充分而全面地反映广播电视的运动情态，忠实而准确地记录广播电视的历史迁延轨迹；及时而正确地介绍和评价广播电视节目及其文化导向，引导和预测广播电视的未来发展趋向；加强广播电视与因特网、电影等传播形态间的互动，寻求印刷媒体与电子媒体的联动和双赢；理清广播电视报与电台、电视台内部资讯等刊物问的工作职能，奠定双方沟通的桥梁与纽带等几个方面的工作，才能在中国已加入WTO这一复杂的情势下获得较大的发展。  相似文献   

Analysis of the insulation capability of polyester insulator     

Ayten Kuntman  Ahmet Merev 《Journal of The Franklin Institute》2005,342(3):285-294

The lifetime of polyester resin samples has been determined with the ASTM D2303 inclined plane tracking test method (IPTTM) for different environmental effects. Most of the external factors have a unique degradation effect, hence the tracking image observed on polyester resin highly depends on these factors. The structure and topography of the tracking patterns generated on the surface of polyester resin have been examined using the fractal dimension model. The accuracy and success of the fractal dimension model can significantly improve the possibility of determining the variety of aging processes that an insulator has been subjected to over a long time period. In order to verify the results, the structures have also been analyzed by using Markov random fields (MRF) and cellular neural networks (CNN).  相似文献   

基于Honeynet系统中的数据控制和数据捕获技术研究     

张家喜 《安徽职业技术学院学报》2005,4(3):1-4

文章介绍了Honeynet系统这一主动防御技术的实现原理以及数据控制和数据捕获技术,进而研究了其采用的先进技术,并对其最新技术的发展趋势进行了展望。  相似文献   

基于多专家和MDNet的视觉目标跟踪方法     

张知明  李国荣  黄庆明 《中国科学院大学学报》2022,39(6):836-844

近年来,随着深度学习技术的不断发展,基于深度学习的目标跟踪算法取得了较大成功。但由于视频中,背景、光照及目标的表观不断变化,且伴有遮挡的发生,给视频中的目标跟踪带来很大困难。传统方法主要通过在线更新跟踪器的方式解决这个问题。但是视频信息内容复杂多变,在线更新和维持一个跟踪器很难应对后续视频中复杂的数据,容易导致误差积累。为解决这个问题,基于已有跟踪器MDNet,提出一种基于多专家跟踪器的目标跟踪方法。首先通过MDNet学习所有视频中目标的共有特征,使其能够较好地描述目标。然后在跟踪过程中,根据跟踪结果动态地构建多个专家跟踪器,以增加跟踪器的鲁棒性。最后根据每个专家的评价函数选择最佳的专家跟踪器,用于跟踪当前帧中的目标。实验表明,与MDNet相比, 所提方法显著地提升了跟踪性能。  相似文献   

刚体滚动中静摩擦力方向的直观判断及作功问题     

王权 《潍坊教育学院学报》2005,18(4):27-28

本文以常见的力学现象为例,从理论上阐述判断静摩擦力方向的方法及作功问题的证明方法。  相似文献   

非理想约束系统的Boltzmann-Hamel型方程及其正则式     

罗绍凯 《湖南城市学院学报》1990,(5)

本文在文献[1]、[2]的基础上,提出带有非理想约束的分析力学的普遍中心方程,建立非理想非线性非完整非保守系统准坐标形式的广义BoltZmann—Hamel方程,并建立与其对应的正则方程,最后讨论线性系、保守系、完转系和理想系情形。  相似文献