Tracking Pre-service Teachers’ Changing Conceptions of Good Science Teaching: The Role of Progressive Reflection with the Same Video

A CD-ROM consisting of videos of two lessons by different teachers demonstrating exemplary science teaching was used to elicit, develop and track the changing conceptions of good science teaching of student teachers enrolled for the one-year Postgraduate Diploma in Education (PGDE) at several stages during the programme. It was found that the videos acted as an effective probe to elicit student teachers’ conceptions and had significant impact on those conceptions at different stages of the programme through the provision of teacher models demonstrating exemplary teaching. The experience has extended novice teachers’ awareness of alternative teaching methods and approaches not experienced in their own schooling, broadened their awareness of different classroom situations, provided proof of existence of good practices and prompted them to reflect on their current conceptions of good science teaching. Most importantly, the strategy of asking student teachers to watch the same videos on three separate occasions at different times of the course was recognized by them as a crucial element in facilitating their reflection on their changing conceptions of good science teaching. PGDE is the standard form of pre-service teacher education in Hong Kong. It provides qualified teacher status within Hong Kong. Student teachers enrolled for the PGDE have completed a relevant undergraduate degree.     

一种在MPEG-4编码过程中提高实时性的算法

本文提出了一种新的在MPEG-4编码过程中提高实时性的算法。算法采用双重筛选机制,充分利用了运动估计的结果提取运动对象。首先在运动估计过程中加入背景优先准则进行第一重筛选;然后根据运动估计后宏块的最小平均绝对差值分利用区域自适应门限进行第二重筛选,从而获得运动区域掩模;最后对掩模进行形态滤波和填充消除噪声点,最终得到运动区域。算法分别在硬件和软件平台上进行测试,结果表明提出的算法得到了理想的分割效果,较传统的在编码前进行运动对象提取的方法实时性大大提高了。     

析运动员赛前排泄频繁的成因

运动员赛前排泄频繁，主要特征是小便次数明显增多和不停的出汗，这种反应，实际上是心理诱导的作用，视为应激性排泄频繁。通过应激学说的论证原理如何加强赛前心理训练的原则和方法，可以缓解和消除赛前紧张和焦虑的应激刺激，使运动员水平得到充分的发挥。     

本体性游戏与幼儿元认知发展的研究

元认知在个体的发展中起着重要的作用。在不同的个体身上,元认知有成熟与次成熟之别,整体与局部之分。幼儿具有局部的次成熟的元认知。在本体性游戏的影响下,幼儿的元认知将获得较快的发展。     

The interplay of representations and patterns of classroom discourse in science teaching sequences

The purpose of this study is to examines the relationship between the communicative approach of classroom talk and the modes of representations used by science teachers. Based on video data from two physics classrooms in Singapore, a recurring pattern in the relationship was observed as the teaching sequence of a lesson unfolded. It was found that as the mode of representation shifted from enactive (action based) to iconic (image based) to symbolic (language based), there was a concurrent and coordinated shift in the classroom communicative approach from interactive–dialogic to interactive–authoritative to non-interactive–authoritative. Specifically, the shift from enactive to iconic to symbolic representations occurred mainly within the interactive–dialogic approach while the shift towards the interactive–authoritative and non-interactive–authoritative approaches occurred when symbolic modes of representation were used. This concurrent and coordinated shift has implications on how we conceive the use of representations in conjunction with the co-occurring classroom discourse, both theoretically and pedagogically.     

基于视频的城市快速路交通流检测及车辆行为监控

提出一种针对城市快速路的视频监控系统,完成交通流及道路异常行为检测.流量检测模块对车辆进行实时跟踪获得各类交通流统计数据,实现快速路车辆运行状况的全面掌控.异常监控模块运用隐马尔科夫模型,对带有时间和空间信息的车辆轨迹进行训练,获得路径划分后对道路车辆轨迹进行参数匹配,提取诸如超低(高)速行驶、违章停车、违规掉头等异常...     

基于录像分析背景下的代数课堂教学语言研究——以两堂《分式的乘除》课堂实录为例

量化分析《分式的乘除》两堂录像课,参考弗兰德提出的"Flanders互动分析系统"师生语言分类,将代数课堂教学语言进行分类,并就不同教学环节,对教学语言比较分析,得出以下结论:(1)课堂教学中,教师的教学语言所用时间占有很高的比例,各种类型的教学语言的时间比例不同,以提问性语言为主;(2)代数课堂教学中两位教师在各个教学环节中教学语言所占时间比例不同,例题讲解、练习讲解环节教师语言所占的比例最大;(3)代数课堂教学各个环节中,教师大多采用提问性为主的教学语言;(4)课堂教学中,应适当减少命令性语言和提问性语言,适当增加启发性语言、反馈性语言和激励性语言,以提高教学效果.     

Video diaries: a tool to investigate sustainability-related learning in threshold spaces

This paper takes as a case study an undergraduate field class from a UK university to rural Uganda. It describes and evaluates the use of video diaries as a tool for investigating the process of transformative learning in the context of education for sustainability. The applicability of threshold concept theory to this learning is investigated. Results show the video diary technique to be much more successful in capturing the development of student learning than written diaries. Despite some practical difficulties, rich data were generated. Analysis demonstrated that learning met three of the five criteria for threshold concepts: the learning was transformative, integrative and troublesome. Further research could test whether the learning in this case study met the threshold concept criterion of irreversibility. Further elaboration of the theoretical relationship between threshold concepts, transformative learning and education for sustainability is also needed. It is concluded that the video diary method is potentially transferable to other educational research contexts and may be particularly suitable for researching learning in threshold spaces.     

3DV quality model based depth maps for view synthesis in FTV system

Depth maps are used for synthesis virtual view in free-viewpoint television (FTV) systems.When depth maps are derived using existing depth estimation methods,the depth distortions will cause undesirable artifacts in the synthesized views.To solve this problem,a 3D video quality model base depth maps (D-3DV) for virtual view synthesis and depth map coding in the FTV applications is proposed.First,the relationships between distortions in coded depth map and rendered view are derived.Then,a precisely 3DV quali...     

Video retargeting using optimized crop-and-scale

Mobile devices are increasingly powerful in multimedia transmitting and browsing. However, the small screen and different aspect ratios of mobile devices lower visual quality while watching images or videos. Video retargeting is aim at fitting an existing video into arbitrary size and aspect ratio. Previous content-aware retargeting methods are mostly high computational cost, which limits their applications on the portable devices with low computation ability. In this paper, a new crop-and-scale approach is presented to adapt video to better suit the target display. We automatically find the optimal parameters of cropping window using the dynamic programming method, and then scale it to fit the target display. The cropping window can smoothly shift during a shot to follow the movement of important objects. The retargeting results using our approach introduce no deformation and jitter effects over the whole video. Experimental results show the success of our approach on adapting a variety of source videos to small display sizes.