运动员与普通大学生在多目标追踪任务中的表现

采用多目标追踪范式(Multiple-Object Tracking,MOT)考察运动员和普通大学生在视觉注意追踪任务中的表现,实验主要探讨分心物数量、目标颜色变化和目标运动形式变化对运动员和普通大学生在视觉注意追踪任务的影响,研究结果表明:无论是运动员还是普通大学生,分心物数量对注意追踪的影响显著;运动员的注意追踪成绩存在性别差异;目标颜色变化的效应显著;三因素交互作用不显著。本研究可以得出如下结论:1)运动员比普通大学生在多目标视觉注意追踪任务中存在明显的反应速度优势,而且要比普通大学生的反应速度快90~200 ms。2)运动员在多目标追踪任务中存在显著的性别差异,男运动员在相同任务中的注意追踪表现显著好于女运动员。3)运动员在注意追踪任务上的反应时优势和性别差异对运动员选拔和运动训练有重要的启示,并可以作为运动员选拔和运动训练的心理指标之一。     

变速恒频双馈风力发电试验系统的研究与实现

变速恒频双馈风力发电机组运行在额定风速以下时,可以进行最大风能捕获,最大效率的利用风能;在额定风速以上,输出功率平稳,且传动系统具有良好的柔性。为了在实验室条件下研究变速恒频双馈风力发电电气控制技术,设计并实现了变速恒频双馈风力发电试验平台主控制系统,对主控制系统的硬件配置和软件结构以及系统所要实现的功能模块进行了详细的探讨。     

基于核密度相关度量的视频目标跟踪

传统的Mean shift 方法采用颜色直方图作为特征,以Bhattacharyya系数作为目标参考模板与当前帧中候选目标间的相似度量,通过迭代寻找距离函数的局部最小值,从而得到当前帧中的目标实际位置。由于颜色直方图仅仅描述了图像中目标的全局颜色分布而忽略了空间位置分布,使得当目标邻域中存在与目标相近似的颜色模式时,算法无法取得理想的跟踪效果。本文提出了基于核密度估计相关的距离度量,在描述参考目标和候选目标时,考虑到诸如颜色、梯度等目标像点的特征区间的同时,融入了目标像点的空间位置信息,使得跟踪算法更加稳健和精确,能够更好适应目标和背景变化复杂的应用场合。     

基于专利引文的技术跟踪可视化研究——共引、互引、他引、自引

科技管理的发展离不开技术跟踪的有效实施.专利引文中蕴藏着大量的重要技术信息,通过专利引文分析,可以有效地跟踪和监控相关技术领域的发展态势.基于此,文章以专利的共引、互引、他引、自引作为研究视角,以数据挖掘、信息萃取、知识发现等技术为手段,开发基于专利引文的技术跟踪可视化工具,并以公路工程领域为例,从技术结构、技术依赖和技术战略定位三个层面进行可视化实验,以期为科技管理的实施做一些基于技术分析的支撑性基础工作.     

基于马尔可夫链蒙特卡罗算法的无线电定位

为实现在多媒体舞台剧中真实空间的目标与多媒体背景的虚拟空间元素间的互动,进行无线电测向定位建模,利用马尔可夫链蒙特卡罗算法进行仿真.实际应用表明,该方法可通过驱动多媒体舞台背景的虚拟场景元素的位置和形态的变化,实现真实空间与虚拟空间的互动.     

Colour-based rigid body tracking using three-dimensional graphics models

This paper introduces the first stage of a new model-based approach to three-dimensional (3D) human movement tracking. A ‘generate-and-test’ matching procedure was adopted by matching rendered images of a 3D computer graphics model of the human body to target images of rigid body motion. The set of pixels to be compared were just those corresponding to the model of the body in the rendered images. The matching criterion to optimize model position and orientation was based on the minimisation of the RGB (red-green-blue) colour difference between generated model images and associated target images. The method was able to track synthetic image sequences of a half twisting somersault accurately with root-mean-square (rms) errors of less than 5 mm and 0.3∘ for position and orientation estimates respectively. The suitability of the proposed approach for rigid body motion tracking was supported by additional tracking experiments on video image sequences of ‘wooden cross’ trajectories. Comparisons of tracked estimates against manual digitizing estimates returned relatively small rms difference values on both side somersault and twisting somersault movements. The proposed approach has the potential to track video images of a human torso using a rigid body model and hence to track articulated movements by successively adding segments to the model in a hierarchical manner.     

运动引起月经情况变化,不影响女运动员婚育——原中国女排队员追踪调查

通过对 42名原中国女排老队员婚后追踪调查 ,分析结果表明激烈运动及比赛会引起月经情况的变化 ,但它是生理变化 ,是暂时性的 ,可恢复的 ,并且不影响婚育     

基于MC9S12DG128单片机智能车设计与实现

该智能车控制系统采用MC9S12DG128 16位单片机作为唯一的核心控制单元,加以直流电机、舵机、光电传感器和电源电路以及其他电路构成。由安装在车前部的反射式红外传感器负责采集信号,并将采集到的电平信号传入核心控制单元,核心控制单元对信号进行判别处理后,由PWM发生模块发出PWM波,分别对转向舵机和直流电机进行控制,完成智能车的转向与前进。智能车后轮上装有霍尔传感器,用来采集车轮转速反馈的脉冲信号,并经由核心控制单元进行PID控制算法处理后会自动调节输入到电机驱动模块的PWM波占空比,从而控制小车的速度。寻迹由RPR220型光电管完成。     

以谱分解方法对随机摄动系统进行最优性能分析

We investigate the best performance for linear feedback control systems in the case that plant uncertainty is to be considered. First, we define an average integral square criterion of tracking error over a class of stochastic model errors. By utilizing spectral factorization to minimize the performance index, we derive an optimal controller design method and further study best performance in the presence of stochastic perturbation. The results can be used to evaluate optimal performance in practical control system designs.     

Time limits in testing: An analysis of eye movements and visual attention in spatial problem solving

Individuals with an aptitude for interpreting spatial information (high mental rotation ability: HMRA) typically master anatomy with more ease, and more quickly, than those with low mental rotation ability (LMRA). This article explores how visual attention differs with time limits on spatial reasoning tests. Participants were assorted to two groups based on their mental rotation ability scores and their eye movements were collected during these tests. Analysis of salience during testing revealed similarities between MRA groups in untimed conditions but significant differences between the groups in the timed one. Question‐by‐question analyses demonstrate that HMRA individuals were more consistent across the two timing conditions (κ = 0.25), than the LMRA (κ = 0.013). It is clear that the groups respond to time limits differently and their apprehension of images during spatial problem solving differs significantly. Without time restrictions, salience analysis suggests LMRA individuals attended to similar aspects of the images as HMRA and their test scores rose concomitantly. Under timed conditions however, LMRA diverge from HMRA attention patterns, adopting inflexible approaches to visual search and attaining lower test scores. With this in mind, anatomical educators may wish to revisit some evaluations and teaching approaches in their own practice. Although examinations need to evaluate understanding of anatomical relationships, the addition of time limits may induce an unforeseen interaction of spatial reasoning and anatomical knowledge. Anat Sci Educ 10: 528–537. © 2017 American Association of Anatomists.