Validation of a videogrammetry technique for analysing American football helmet kinematics     

Ann Bailey  James Funk  David Lessley  Chris Sherwood  Jeff Crandall  William Neale 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(5):678-700

ABSTRACT

Professional American football games are recorded in digital video with multiple cameras, often at high resolution and high frame rates. The purpose of this study was to evaluate the accuracy of a videogrammetry technique to calculate translational and rotational helmet velocity before, during and after a helmet impact. In total, 10 football impacts were staged in a National Football League (NFL) stadium by propelling helmeted 50th percentile male crash test dummies into each other or the ground at speeds and orientations representative of concussive impacts for NFL players. The tests were recorded by experienced sports film crews to obtain video coverage and quality typically available for NFL games. A videogrammetry procedure was used to track the position and rotation of the helmet throughout the relevant time interval of the head impact. Compared with rigidly mounted retroreflective marker three dimensional (3-D) motion tracking that was concurrently collected in the experiments, videogrammetry accurately calculated changes in translational and rotational velocity of the helmet using high frame rate (two cameras at 240 Hz) video (7% and 15% error, respectively). Low frame rate (2 cameras at 60 Hz) video was adequate for calculating pre-impact translational velocity but not for calculating the translational or rotational velocity change of the helmet during impact.  相似文献   

大型体育赛事传播助力成都市城市形象优化路径研究     

张为芳  韩海军 《当代体育科技》2020,(9):197-198

体育赛事的举办是城市发展的需求,一个城市大型体育赛事的成功举办,不仅能积极提高城市的知名度和影响力,还能展现出主办城市的文化建设发展风貌,增强城市对外的吸引力。本文运用文献资料法、问卷调查法、数理统计法等研究方法,以2019国际篮联三对三世界巡回大师赛(成都站)为研究对象,探索大型赛事对提升赛事传播力和形象上的提升,进而研究助力成都市城市形象优化路径的方法。建议:搭建多元化的传播策略,扩大宣传辐射面;激发全民参与运动的热情,增加全民健身设施;聚焦赛事文化创意产业,带动经济多样化发展。  相似文献   

武术与民族传统体育学科建设目标、困境及出路   总被引：1，自引：0，他引：1  

麻江利 《广州体育学院学报》2020,(1):67-70

武术与民族传统体育学作为一门学科尚显稚嫩,其突出表现是学科知识缺乏独立性。综合运用文献资料、归纳演绎、比较分析等研究方法,沿着目标→困境→出路的逻辑线路,对武术与民族传统体育学学科建设问题展开深入探讨。主要观点:1)特色鲜明乃武术与民族传统体育学学科建设的目标,该目标达成所倚赖之原动力是实践内容的相对独立;2)边界模糊是阻碍武术与民族传统体育学学科建设保持特色鲜明、走向成熟的重要理论致因;3)反求诸己是武术与民族传统体育学学科建设打破边界模糊困境、实现特色鲜明目标的出路。如此,武术与民族传统体育学方能因获得独立性而有成长壮大之可能,才有希望摆脱学科依附阴影,乃至问鼎显学的地位。  相似文献   

媒介权力对体育媒体传播中女性形象的影响研究*     

刘〓婷  宋宗佩  冯培明  孙晨晨 《广州体育学院学报》2020,(3):46-49

媒介权力作为第四种权力，影响着媒介形象的塑造。运用文献资料、逻辑分析和理论分析等研究方法，就媒介权力对女性形象的影响进行研究。研究发现，社会责任理论要求，体育媒体有必要塑造健康的女性形象。受媒介权力的正面影响，体育媒体中女性形象的塑造，表现出传播主体多元化、传播内容丰富化、传播途径多样化和传播受众理性化等特征。然而，以媒介缺位、媒介错位和媒介越位为表征的媒介权力异化，塑造了有偏差的女性形象，引发了受众对女性的不合理认知。未来受媒介权力的影响，体育媒体应在全媒介时代背景下丰富女性体育传播媒介，机会均等观念下均衡配备传播主体，性别平等理念下合理发布传播内容，培养理论视域下积极引导传媒受众，以促进体育领域性别平等观念的发展。  相似文献   

对2019年中国电视剧研究的分析与反思     

金丹元  陈莎 《美育学刊》2020,11(2):47-54

2019年正值新中国成立70周年,我国电视剧创作出产了许多革命历史题材和现实主义电视剧佳作,同时网络剧也开始从边缘走向中心,成为观众喜闻乐见的电视剧形式。通过梳理、概括国内重要的学术期刊、报纸和会议论文中关于电视剧研究的文章,并从内容创作、美学价值、类型特点和女性塑造等几个方面进行解读,可以归纳出本年度电视剧研究的热点和焦点,同时也提出了对电视剧研究新动向的一些看法,以期为电视剧研究和创作提供借鉴。  相似文献   

一种在轨海上多运动舰船目标检测和跟踪方法     

矫腾章  胡玉新  吕鹏  张凯  台宪青 《中国科学院大学学报》2020,37(3):368-378

传统遥感卫星图像处理采用在地面进行目标检测和跟踪处理的模式，卫星将拍摄到的图像数据下传至地面数据处理中心，由地面数据处理系统对接收到的遥感图像数据进行目标检测和跟踪。然而，随着遥感图像分辨率的不断提高，需要下传的数据量增大，导致星地数据传输的时间大大增加，最终造成目标检测和跟踪的时效性降低。针对上述问题，提出一种基于多特征量判别的Canny边缘检测和联合概率数据关联的在轨海上多运动舰船目标检测和跟踪方法。将该方法利用中国科学院微小卫星创新研究院的高分微纳卫星实测数据在模拟星载的嵌入式开发平台上进行验证，结果表明该方法能够在轨对海上多运动舰船目标进行快速、准确的检测和跟踪。  相似文献   

“植物”书写:国民性批判与理想人格的载体——李佩甫小说的植物意象分析     

《信阳师范学院学报(哲学社会科学版)》2018,(4):109-113

大量植物意象的运用是李佩甫小说的一个较为明显的特征,透过这些植物意象,那些生活在同一块土地上的"平原人"形象跃然纸上。隐喻乡村女性的乡间最常见的"牛屎饼花",折射出平原人"败中求生,小中求活"的生存本能的"小虫儿窝蛋"和"败节草",还有充满神秘色彩的"汗血石榴""人面橘"等,所有这些意象都无疑为我们洞悉作家是如何解读社会的提供了一个切入点,从而成为理解李佩甫小说的关键。  相似文献   

High-resolution mapping of brain vasculature and its impairment in the hippocampus of Alzheimer's disease mice     

Xiaochuan Zhang  Xianzhen Yin  Jingjing Zhang  Anan Li  Hui Gong  Qingming Luo  Haiyan Zhang  Zhaobing Gao  Hualiang Jiang 《国家科学评论(英文版)》2019,6(6):1223

Accumulating evidence indicates the critical importance of cerebrovascular dysfunction in the pathogenesis of Alzheimer''s disease (AD). However, systematic comparative studies on the precise brain vasculature of wild-type and AD model mice are still rare. Using an image-optimization method for analysing Micro-Optical Sectioning Tomography (MOST) data, we generated cross-scale whole-brain 3D atlases that cover the entire vascular system from large vessels down to smallest capillaries at submicron resolution, for both wild-type mice and a transgenic (APP/PS1) mouse model of AD. In addition to distinct vascular patterns in different brain regions, we found that the main vessels of the molecular layer of the hippocampal dentate gyrus (DG-ml) undergo abrupt changes in both diameter and branch angle, spreading a unique comb-like pattern of capillaries. By using a quantitative analysis workflow, we identified in the hippocampus of AD mice an overall reduction of the mean vascular diameter, volume fraction and branch angle, with most significant impairment in the DG-ml. In addition, virtual endoscopy revealed irregular morphological features in the vessel lumen of the AD mice, potentially contributing to the impairment of blood flow. Our results demonstrate the capability of high-resolution cross-scale evaluation of brain vasculature and underscore the importance of studying hippocampal microcirculation for understanding AD pathogenesis.  相似文献   

Writer identification approach based on bag of words with OBI features     

Amal Durou  Ibrahim Aref  Somaya Al-Maadeed  Ahmed Bouridane  Elhadj Benkhelifa 《Information processing & management》2019,56(2):354-366

Handwriter identification aims to simplify the task of forensic experts by providing them with semi-automated tools in order to enable them to narrow down the search to determine the final identification of an unknown handwritten sample. An identification algorithm aims to produce a list of predicted writers of the unknown handwritten sample ranked in terms of confidence measure metrics for use by the forensic expert will make the final decision.Most existing handwriter identification systems use either statistical or model-based approaches. To further improve the performances this paper proposes to deploy a combination of both approaches using Oriented Basic Image features and the concept of graphemes codebook. To reduce the resulting high dimensionality of the feature vector a Kernel Principal Component Analysis has been used. To gauge the effectiveness of the proposed method a performance analysis, using IAM dataset for English handwriting and ICFHR 2012 dataset for Arabic handwriting, has been carried out. The results obtained achieved an accuracy of 96% thus demonstrating its superiority when compared against similar techniques.  相似文献   

日韩武技现代化对我国学校武术的启示     

张长念  张长思 《武汉体育学院学报》2020,54(3):63-69,91

时至今日,武术仍未能很好地进入校园,其原因何在,如何从柔道、跆拳道、空手道的成功现代化和国际化当中寻求启发,成为紧迫论题。主要运用文献资料法,基于对学校武术历史、现状的反思和日韩武技现代化的启示,对我国学校武术的根本问题和根本方略做出探讨。研究认为,学校武术开展的现状不能实现中华民族赋予它的文化使命,日韩武技现代化的经验可为我们提供启示——将传统意义上的搏杀武技改造为一项现代文明搏击项目,该项目需满足几个趋势保证安全文明化、保持技击本质性、具有游戏趣味性、彰显民族独特性。在此基础上,做出武术以太极推手形式进入校园的提案。  相似文献