基于车辆导航的一种改良动态最短路径算法     

张一珂  刘鸿剑  朱志斌 《科技广场》2009,(5):26-28

车辆导航的一个基本问题是如何在一个即时的动态交通网中找到最优路径,现有的算法不是太复杂,就是不能很好地处理当移动物体的位置及交通环境同时发生变化所造成的复杂环境.本文推荐一种A*算法的变种-A*终身计划(Lifelong Planning A*,LPA*),并在该算法的基础上进行了改良,提出了采用特定椭圆修剪不必要的查询节点,以提高动态搜索的速度.  相似文献   

Predictors and outcomes of core and peripheral sport motivation profiles: A person-centered study     

István Tóth-Király  Camille Amoura  Beáta Bőthe  Gábor Orosz  Adrien Rigó 《Journal of sports sciences》2020,38(8):897-909

ABSTRACT

While previous studies highlighted the importance of the different motivations for doing sports as proposed by self-determination theory, less emphasis has been put on the simultaneous presence of multiple motivations within the same individual. Therefore, the present study aimed to investigate the complex interaction of sport motivations and to identify core (common) and peripheral (uncommon) profiles of people engaged in sports based on a combination of motivations. To achieve this goal, latent profile analysis, a person-centered approach, was performed on responses from 506 participants engaged in sports. For better understanding the extracted profiles, basic psychological need fulfillment was included as profile predictor, while subjective vitality and various engagement-related indicators as outcomes. Four core and peripheral profiles were identified: Moderately Motivated, Highly Motivated, Amotivated, and Poorly Motivated. Contrary to theory, introjected regulation clustered more closely with self-determined motivations. Profile membership was significantly predicted by global need fulfillment, autonomy satisfaction as well as, to a smaller extent, autonomy, relatedness, and competence frustration. The four profiles differed along vitality and some, but not all, engagement-related outcomes.  相似文献   

MPA或VPA等时替代课堂10分钟LPA对高中生体质健康的影响     

蔡瑞金  薛小安  季浏  王诚 《武汉体育学院学报》2021,55(3):82-91

目的：探究体育课堂不同运动强度累积时间与体质健康之间的关系。方法：用Actigraph wGT3X-BT采集360名城区和郊区高中生40 minSB、LPA、MPA、VPA累积时间和7日总佩戴时间,并统一进行体质健康测试,运用SPSS23.0对各项指标进行相关分析、回归分析和等时替代分析。结果：（1）在体育课上高中男生MPA、VPA运动时间均显著高于女生,体质健康水平也存在显著性性别差异;（2） LPA运动时间与各项目（立定跳远除外）之间无关,SB、MPA、VPA运动时间与体质健康大部分项目之间均显著相关;（3）对于高中男生,VPA运动时间对立定跳远、引体向上、坐位体前屈,MPA运动时间对肺活量和1000m单独产生有益影响;LPA运动时间对立定跳远、引体向上、坐位体前屈,SB时间对1000m单独产生不利影响;在控制LPA运动时间后,VPA和MPA运动时间对相关体质健康的有益影响减弱;在等时替代LPA后,VPA和MPA运动时间对相关体质健康的有益影响增强;（4）对于高中女生,SB、LPA、MPA与VPA运动时间对体质健康各项目的单独和等时替代影响均不显著,在控制LPA后,SB时间显著提高女生50m速度。结论：目前上海市高中生体育课低于50% MVPA运动时间,MPA运动时间具有发展男生肺活量和1000m的特异性,VPA运动时间具有发展男生立定跳远、引体向上、坐位体前屈和50m的特异性,加速度计测量的课堂SB为肌肉力量和柔韧练习,但是高中女生体质健康的改善需要克服传统体育课程长期运动强度不足的负面效应。  相似文献