基于核密度估计多样性采集的背景建模算法

1IntroductionBackground subtraction methods are extensively ex-ploited for moving object detection in videos in manyapplications ,such as traffic monitoring[1],human mo-tion capture[2]and video surveillance[3]. The centralidea behind such methods is to segment foreground ini mage sequences taken from a fixed camera by com-paring each newframe to a model of the scene back-ground . Therefore , correctly and efficiently modelingand updating the background model is one of the mostchallenging aspec…     

Length-based vehicle classification in multi-lane traffic flow

For the realtime classification of moving vehicles in the multi-lane traffic video sequences, a length-based method is proposed. To extract the moving regions of interest, the difference image between the updated background and current frame is obtained by using background subtraction, and then an edge-based shadow removal algorithm is implemented. Moreover, a thresholding segmentation method for the region detection of moving vehicle based on location search is developed. At the estimation stage, a registration line is set up in the detection area, then the vehicle length is estimated with the horizontal projection technique as soon as the vehicle leaves the registration line. Lastly, the vehicle is classified according to its length and the classification threshold. The proposed method is different from traditional methods that require complex camera calibrations. It calculates the pixel-based vehicle length by using uncalibrated traffic video sequences at lower computational cost. Furthermore, only one registration line is set up, which has high flexibility. Experimental results of three traffic video sequences show that the classification accuracies for the large and small vehicles are 97.1% and 96.7% respectively, which demonstrates the effectiveness of the proposed method.     

减法工程疗法与清理内环境

用十五年医疗实践,初步总结出“减法工程”疗法,是在针刺经络、断食辟谷后通过清除体内非实体性物质而使代谢障碍消失,以证明它和治理物质实体性毒物同样重要。     

智能交通系统中视频背景实时更新技术的改进研究

车辆检测是智能交通系统（ITS）的核心。探讨采用自适应算法对背景进行实时更新的方法,能有效削弱恶劣天气和环境变化在画面上产生的各种噪声。实验表明此方法具有很好的实时性,能满足视频车辆检测的要求。还探讨了一种在堵车的复杂环境下背景的实时更新算法,用前景静止物体表面灰度值的变化量,来估算背景的改变量,从理论上解决停车及车辆缓行条件下的背景更新问题,达到扩展背景差法通用性的问题。     

Three-dimensional tracking of GLUT4 vesicles in TIRF microscopy

TIRF microscopy has provided a means to view mobile granules within 100 nm in size in two dimensions. However quantitative analysis of the position and motion of those granules requires an appropriate tracking method. In this paper, we present a new tracking algorithm combined with the unique features of TIRF. Firstly a fluorescence correction procedure was processed to solve the problem of fluorescence bleaching over time. Mobile granules were then segmented from a time-lapse image stack by an adaptive background subtraction method. Kalman filter was introduced to estimate and track the granules that allowed reducing searching range and hence greater reliability in tracking process. After the tracked granules were located in x-y plane, the z-position was indirectly inferred from the changes in their intensities. In the experiments the algorithm was applied in tracking GLUT4 vesicles in living adipose cells. The results indicate that the algorithm has achieved robust estimation and tracking of the vesicles in three dimensions.     

小学数学教学中的表现性评价及其应用

构建科学合理的评价方式,通过评价更好地了解学生的学习,并以评价改进教学,成为近来教育教学中非常值得关注的话题。表现性评价运用于小学数学教学中,能更好地了解学生的数学理解水平并有效改进教学。以“两位数减一位数退位减法”为例,制定了算理理解的水平框架并设计了表现性任务,对学生的算理理解水平和学习过程进行了测评。最后,合理应用表现性评价框架及测评,有针对性地进行了教学设计,有效促进了学生对算理的理解水平。     

Mental Calculation Methods Used By 11-Year-Olds in Different Attainment Bands: a reanalysis of data from the 1987 APU survey in the UK

This paper describes thereanalysis of data obtained in 1987 on themental calculation strategies used by asample of 11-year-olds in the course of anational survey of schools in England,Wales and Northern Ireland. The mentalskills test was administered to pupils in aone-to-one situation and the reanalysismade use of classifications of mentalstrategies developed in the past decade ininternational research. These pupils werea subsample of the main sample of about 10000 who took a written test of mathematicsin the survey, 247 taking both tests. Thescores on the written test were used todistribute these pupils into three bands ofattainment in order to compare thefrequency and effectiveness of thestrategies used by pupils of differentlevels of attainment. Eight of thereanalysed questions are discussed, each ofthem involving one of the four basicarithmetic operations. Some are purelynumerical and in others the numbers are ina context. Top band pupils mostly preferredsequential strategies which leave one ofthe numbers in the calculation complete,while the Bottom band generally preferredto split complete numbers and operateseparately on the components of the numbersthus partitioned. The most popularstrategy for Middle band pupils in severalquestions was the standard algorithm usedmentally. Complete number strategies werethe most successful for pupils in all threebands. Possible implications for theNational Numeracy Strategy in Britain arediscussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

减法：媒介特征新阐释

一种媒介,人们如果只知道可以做什么,而不明了不能做什么,这种媒介在运作中肯定存在很多盲目的因素。减法媒介特征阐释法通过排除的操作,现出事物的本质。具体在媒介的分析上是在避短的基础上扬长。在现有的科技水平下还没有全方位的体验式的媒介,只有采用减法媒介特征阐释法才能自觉地启动媒介补偿机制。采用减法媒介特征阐释法能促使媒介操作规范形成,还能发现媒介所产生的非切身性的特殊感受也可称为媒介感受。     

Assessment of subtraction scene understanding using a story‐generation task

The present study used a new assessment technique, the story‐generation task, to examine students’ understanding of subtraction scenes. The students from four grade levels (110 first‐, 107 third‐, 110 fourth‐ and 119 sixth‐graders) generated stories under the constraints provided by a picture (representing Change, Combine or Compare scene) and a number sentence. The results showed that the Change scene was the most intuitive, and the students tended to reinterpret Combine and Compare scenes as a form of Change scene, even when they understood that the identity of the objects in the Combine and the Compare scenes was different. The number of students generating correct stories for the Combine scene increased through the elementary school grades while for the Compare scene the number of students generating correct stories remained fairly constant from Grade 3 to Grade 6. This study also examined students’ exposure to subtraction scenes in mathematics textbooks and discussed educational implications for supporting students’ understanding of subtraction scenes.