提高多媒体教室音质与图像清晰度的探讨

多媒体教室的音质与图像清晰度,直接影响着教学信息的传递和教学的质量。如何获得理想的听音效果,既能保证语言的清晰度,又能保证音乐、效果声的保真度;如何最大限度地提高图像清晰度。文章从声学设计、音响系统设计与配接、视频系统的选型与配接等方面进行了探讨。     

Reasonable expectations of privacy

Use of the concept of `areasonable person and his or her expectations'is widely found in legal reasoning. This legalconstruct is employed in the present article toexamine privacy questions associated withcontemporary information technology, especiallythe internet. In particular, reasonableexpectations of privacy while browsing theworld-wide-web and while sending and receivinge-mail are analyzed.     

Exploring student hand-raising across two school subjects using mixed methods: An investigation of an everyday classroom behavior from a motivational perspective

Student hand-raising is an everyday behavior in classroom interactions with teachers. This research presents two studies that examine the variance in hand-raising and its relation to student motivation in two school subjects, Mathematics and Language Arts. Student hand-raising is introduced as an indicator of behavioral engagement. Study 1 investigated N = 397 high school students in 20 classrooms during a videotaped lesson in each subject. Multilevel regression analysis suggests that student motivation accounts for significant variance in hand-raising. The results show subject-specific differences: Student self-concept predicts hand-raising in Mathematics, while students' situational interest predicts their hand-raising in Language Arts. Students’ externally regulated motivation is predictive across both subjects. In Study 2, N = 14 high school students were interviewed about their hand-raising behavior. The results validate and extend the findings from Study 1. Finally, this research emphasizes the importance of fostering student hand-raising and discusses the implications for future research.     

一种基于混沌加密的视频水印方法

利用二维混沌流加密技术加密有意义的二进制图像,获得水印数据,以提高视频水印的安全性。水印嵌入过程中,水印被嵌入到随机选择的视频帧的离散余弦变换系数里。在鲁棒性和帧平均攻击实验后,大部分水印可以通过水印检测提取算法进行提取和识别。实验结果表明,这种视频水印方法具有一定的安全性、隐蔽性和鲁棒性。     

基于互信息量的视频关键帧提取算法

关键帧提取技术是基于内容检索和视频分析的基础。关键帧的使用减少了视频索引的数据量,同时也为视频摘要和检索提供了一个组织框架。首先介绍了目前关键帧提取技术,然后提出了一种基于互信息量的关键帧提取方法,该算法以帧间互信息量来衡量两帧图像内容的相似性,可以对具体镜头按其特点自动提取出一个或多个关键帧。实验结果表明这种方法可以较好地概括视频内容。     

浅析视频技术的发展和应用

当前视频技术发展迅速且应用广泛,然而视频格式的不统一、编码技术的多样性却给视频的创建和使用带来了诸多不便。本文就各类视频文件的特点、应用和转换方式进行了深入的分析和探讨。     

基于流媒体技术的网络视频资源库的构建

信息技术的飞速发展,使以多媒体通信技术为基础的流媒体技术得到了越来越广泛的应用。流媒体以其边播放边下栽的特性,成功地解决了多媒体信息网上传输的问题,使网络教学中的学习资源建设模式发生了重要变化。     

无盘网络与数字图书馆

通过无盘网络与有盘网络的比较，提出无盘网络作为新图书馆部分网络选型的解决方案以及无盘网络在数字图书馆中的应用。     

“It Lets Me Fight the Bad Guys”: An Exploration Into the Factors Predicting Enjoyment of Violent Video Games

In an exploratory survey that sampled video gamers, participants were asked to indicate why they enjoy playing their favorite video game. On the basis of ESRB ratings, we compare those whose favorite game is violent to those whose favorite game is nonviolent. Consistent with self-determination theory, the findings suggest need for autonomy and competence are important motivating factors. However, the findings also suggest fans of violent games differed from fans of nonviolent games in the degree to which arousal, liking violence, playing the vicarious hero, and playing the vicarious villain drive enjoyment. Furthermore, being able to play the hero and “fight bad guys” was a significant predictor of enjoyment of violent games. Implications for self-determination theory and theories of media enjoyment are discussed.     

Social Comparisons and Need Fulfillment: Interpreting Video Game Enjoyment in the Context of Leaderboards

This study examines how social comparison information provided by video game leaderboards may influence players’ retrospective judgments of autonomy, competence, and relatedness need fulfillment. Participants played a video game and were randomly assigned to receive no postgame feedback or were shown a leaderboard that placed them in the top or bottom quartile of players. Results indicate downward social comparisons increase enjoyment by increasing competence and relatedness perceptions. However, upward comparisons did not have an opposite effect, nor did either type of social comparison influence players’ autonomy perceptions. Implications for applying Self-Determination Theory to video game enjoyment in the context of social comparison feedback is discussed.