多媒体视讯会议技术的分析与比较

多媒体视讯会议技术的发展经历了基于电路交换网络和基于lP网络的两个阶段,随着网络宽带技术的发展和普及,多媒体视讯技术的逐步成熟,人们对多媒体视频业务及应用的概念逐步了解,并在视讯会议、远程医疗、远程教育、远程监控、家庭娱乐、流媒体技术、移动视频通信等多个方面都有的广泛应用。本文分析了H.320、H.323、SIP三种视讯技术,然后比较了它们的差异,最后得出SIP协议必将是多媒体视讯会议的主宰。     

数码影像多媒体在体操课保护与帮助教学中的作用

为了解决体操课保护与帮助教学中,没有会做动作的学生协助,教师难以独自进行示范教学的问题,借助数码影像技术,有针对性地整合教学材料,对体操保护与帮助教学过程进行改革。与以往的教学相比较发现:新方法不但解决了没有学生会做动作时教师难以示范教学的困难,而且,还能促进学生掌握保护与帮助的技能和方法。     

Using iPad tablets for self‐modeling with preschoolers: Videos versus photos

As technology becomes more accessible and acceptable in the preschool setting, teachers need effective strategies of incorporating it to address challenging behaviors. A nonconcurrent delayed multiple baseline design in combination with an alternating treatment design was utilized to investigate the effects of using iPad tablets to display video self‐modeling and activity photos for three preschoolers during circle time. During baseline, all three children demonstrated low levels of engagement and high levels of off‐task behavior compared to peers. The intervention phase consisted of alternating between showing the child the self‐video and photos prior to circle time. A child preference phase was conducted whereby each child self‐selected the video or photo prior to circle time. For all three children both videos and photos led to increased engagement and decreased off‐task behaviors. During the child preference phase, all three children selected the video most frequently. Social validity data demonstrated teacher and child preference for the video self‐modeling condition.     

What if best practice is too expensive? Feedback on oral presentations and efficient use of resources

We evaluate feedback methods for oral presentations used in training non-quantitative research skills (literature review and various associated tasks). Training is provided through a credit-bearing module taught to MSc students of banking, economics and finance in the UK. Monitoring oral presentations and providing ‘best practice’ feedback is very resource-intensive. Do we withdraw oral presentations from the module, because best feedback practice is prohibitively expensive in a world of limited resources, or choose a second-best alternative? To what extent might the latter compromise intended learning outcomes? We used the same provision of video feedback for all students but used two verbal feedback regimes. For one regime, we decreased the amount of verbal feedback and increased the number of presentations. The impact was measured by academic outcome, rating scales and questionnaire. Overall satisfaction with the module was very high for both feedback regimes, and there were no statistically significant differences between regimes, suggesting that less resource-intensive methods need not compromise learning outcomes.     

Review of The Atlas of Erotic Anatomy and Arousal

The Atlas of Erotic Anatomy and Arousal is online video education that explores sexual pleasure and sexual anatomy from a sex positive perspective. Written and presented by a sex educator and therapist, Cyndi Darnell, this video is an excellent resource for adult individuals interested in learning about their bodies and having fulfilling sexual experiences with their partners. The video series provides scientifically accurate and pleasure-based information about the anatomy of the vulva, the penis, and the anus, and the physiology of orgasm and ejaculation, in an entertaining manner.     

Leveling the playing field in ICT design: Transcending knowledge roles by balancing division and privileging of knowledges

Abstract

This article develops a conceptual model of users’ and designers’ knowledge roles in the information and communication technology design process. The “ideal” center at the intersection of the axes for division of knowledge work and privileging of knowledges represents a balanced distribution of knowledge work between users and designers and an avoidance of privileging either group over the other. The article then applies this model to analyses of the design process for six video games wherein the knowledges of Indigenous peoples in North America were mobilized. It concludes by discussing implications for research and design practice, particularly for broadening the participation and self-articulation of marginalized groups.     

数字图书馆中基于内容的视频拷贝检测关键技术研究

随着数字图书馆中数字视频资源的增长,数字视频版权保护问题逐渐暴露出来。基于内容的视频拷贝检测技术作为一种有效的版权保护技术,近年来逐渐受到研究人员的关注。本文对基于内容的视频拷贝检测的关键技术视频指纹提取和指纹匹配的研究成果进行了分析,总结了指纹提取和指纹匹配的研究现状,指出了该领域存在的问题,最后分析了该领域的发展方向。     

舞台视效联动控制系统软件设计与实现

解析一款舞台视效设备联动控制系统,可实现对舞台灯光、LED屏、投影等视效设备的联动控制,根据应用特点设计软件结构,并在实现中加以优化。     

Videobased lesson analysis: Effective science PD for teacher and student learning

The Science Teachers Learning from Lesson Analysis (STeLLA) project is a videobased analysis‐of‐practice PD program aimed at improving teacher and student learning at the upper elementary level. The PD program developed and utilized two “lenses,” a Science Content Storyline Lens and a Student Thinking Lens, to help teachers analyze science teaching and learning and to improve teaching practices in this year‐long program. Participants included 48 teachers (n = 32 experimental, n = 16 control) and 1,490 students. The STeLLA program significantly improved teachers' science content knowledge and their ability to analyze science teaching. Notably, the STeLLA teachers further increased their classroom use of science teaching strategies associated with both lenses while their students increased their science content knowledge. Multi‐level HLM analyses linked higher average gains in student learning with teachers' science content knowledge, teachers' pedagogical content knowledge about student thinking, and teaching practices aimed at improving the coherence of the science content storyline. This paper highlights the importance of the science content storyline in the STeLLA program and discusses its potential significance in science teaching and professional development more broadly. © 2011 Wiley Periodicals, Inc., J Res Sci Teach 48: 117–148, 2011     

一种免除二值化的视频叠加中文字符识别方法

提出一种新的用于识别视频中字幕文字的方法。鉴于视频中文字的大小、颜色、渲染风格和分辨率的不同,以及视频中各种复杂背景的影响,识别视频中的叠加文字是一个尚未解决的问题。目前,大多数视频叠加文字识别方法都基于视频文字的二值化和传统OCR引擎的结合。然而,二值化过程容易引入噪声和文字笔划信息的丢失。另外,传统OCR技术主要专注于高分辨率的扫描打印文档,这些文档具有背景单一、噪声少和笔划信息较完整的特点。因此,传统OCR引擎用于识别叠加文字二值化后的结果可能不够鲁棒。为解决这个问题,直接从未二值化的叠加视频文字图像中提取Gabor特征用于训练二层字符识别器。实验结果表明,本文提出的方法在多字体视频叠加中文文字识别上有良好的效果。