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INTRODUCTION Video streaming service nowadays enjoys ex- plosive adoptions over all kinds of underlying net- works. To enjoy the freedom of tether-less connection over the wireless local area network (WLAN), we need to overcome many challenges of unstable wire- less channel due to fading, interference and so on. The scarce and fluctuating available bandwidth (together with time-varying delays and random/burst losses) can cause the video quality at the streaming client to be seriously deg… 相似文献
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Peer-to-peer （P2P） technology provides a cost-effective and scalable way to distribute video data. However, high heterogeneity of the P2P network, which rises not only from heterogeneous link capacity between peers but also from dynamic variation of available bandwidth, brings forward great challenge to video streaming. To attack this problem, an adaptive scheme based on rate-distortion optimization （RDO） is proposed in this paper. While low complexity RDO based frame dropping is exploited to shape bitrate into available bandwidth in peers, the streamed bitstream is dynamically switched among multiple available versions in an RDO way by the streaming server. Simulation results show that the proposed scheme based on RDO achieves great gain in overall perceived quality over simple heuristic schemes. 相似文献
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薛峰 《安徽技术师范学院学报》2014,(6):52-56
传统的DTN（Delay Tolerate Network）缓存调度策略,是根据报文的生命周期或者报文进入缓存的时间来决定报文的优先级别,并没有考虑信源节点本身的特性。针对这一问题,提出节点转发率的概念,用以表明信源节点对网络递交率的贡献。在考虑报文生命周期的同时,根据报文源节点的转发率来进行缓存调度：优先转发源节点转发率高的报文,优先丢弃源节点转发率低的报文。仿真实验表明,将该算法应用于蔓延路由,在显著改善递交率的同时,还能有效减少网络的开销。 相似文献
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基于Matlab的无人机侦察视频处理的GUI设计 总被引：1，自引：0，他引：1
针对无人机侦察视频序列抖动剧烈、聚焦困难、目标匹配难等特点,借助Matlab平台,构建了1个实现视频稳定、聚集评估和跟踪匹配等功能的无人机侦察视频处理模块.该模块能有效降低无人机侦察视频序列的抖动特性,并实现了目标聚集评估、跟踪及关键帧提取等一体化功能,在无人机侦察视频处理领域具有良好的应用前景. 相似文献
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Matjaž Debevc Zoran Stjepanovič Andreas Holzinger 《Interactive Learning Environments》2013,21(1):35-50
Web-based and adapted e-learning materials provide alternative methods of learning to those used in a traditional classroom. Within the study described in this article, deaf and hard of hearing people used an adaptive e-learning environment to improve their computer literacy. This environment included streaming video with sign language interpreter video and subtitles. The courses were based on the learning management system Moodle, which also includes sign language streaming videos and subtitles. A different approach is required when adapting e-learning courses for the deaf and hard of hearing: new guidelines must be developed concerning the loading and display of video material. This is shown in the example of the e-learning course, ECDL (European Computer Driving Licence). The usability of the e-learning course is analyzed and confirmed using two methods: first, the Software Usability Measurement Inventory (SUMI) evaluation method, and second, the Adapted Pedagogical Index (AdaPI), which was developed as part of this study, and gives an index to measure the pedagogical effectiveness of e-learning courses adapted for people with disabilities. With 116 participants, of whom 22 are deaf or hard of hearing, the e-learning course for the target group has been found suitable and appropriate according to both evaluation methods. 相似文献
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ZHU Xiao-liang YANG Zong-kai DU Xu CHENG Wen-qing 《浙江大学学报(A卷英文版)》2006,7(10):1702-1708
INTRODUCTION Video streaming applications generally require continuous high bandwidth guarantees as well as stringent bounds on delays and jitters (Shen et al., 2004; Hassan and Krunz, 2004). Providing video streaming with acceptable quality degradation over wireless channels is fraught with challenges due to the adverse influence of bandwidth limitation, time variation, high error rate, and so on (Etoh and Yo- shimura, 2005; Shen et al., 2004; Chen and Zakhor, 2004; Hassan and Krunz, … 相似文献
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传统流媒体平台对服务器性能,网络带宽等条件要求较高,对校园网的视频应用服务有一定的局限性。为解决此问题,设计了一种基于P2P架构的流媒体视频教学平台,将流媒体技术的实时性和P2P网络的分布性完美地结合起来,实现了视频直播和点播功能。 相似文献
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文章详细的分析了基于Haar小波的视频通信量控制的实现原理,并将它应用在了远程教学的流媒体视频点播系统中,设计了该系统的结构图和工作流程. 相似文献
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INTRODUCTION Video content will be the main contributor to the future traffic in multimedia applications. Camcorders, digital cameras and lately mobile phones with video capturing capabilities have resulted in a wide spreading of multimedia to the masses. Quality of the captured/rendered videos is likely to be the major determining factor in the success of the new multi- media applications as well as product differentiation. Video processing chain includes video capturing, video pre-proce… 相似文献
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Elif Taslibeyaz Onur Burak Dursun Selcuk Karaman 《Interactive Learning Environments》2017,25(8):1025-1034
This study aimed to compare the effects of interactive and non-interactive videos concerning the autism spectrum disorder on medical students’ achievement. It also evaluated the relation between the interactive videos’ interactivity and the students’ decision-making process. It used multiple methods, including quantitative and qualitative methods. The participants were 60 medical students, divided into two groups. One group watched an interactive video while the other watched a non-interactive video. Pre- and post-tests were used to evaluate the students’ relevant achievements in each group. Moreover, a think-aloud protocol was used to evaluate the decision-making process of the group who watched the interactive video. The pre- and post-test results indicated an increase in the achievements of students in the tested groups. Students who watched the interactive video were found to be more successful. Finally, watching interactive videos was shown to positively affect medical students’ decision-making process. 相似文献
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该文研究了文化遗产数字视频云平台的安全问题,研究并实现了相应的流媒体影像网站,探索云平台上文化遗产数字视频的安全问题,在此基础上,提出了一种视频加密算法VEA,VEA密码算法用来保证云平台上文化遗产数字视频文件的安全。依托校园网环境,向校内用户提供自由视频点播服务,对古村古镇文化遗产数字视频文件较好的实现了组织、利用和管理。 相似文献
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SCORM运行时环境支持流式视频点播是丰富SCORM课件媒体展现能力的关键技术,但在当前成品系统中鲜有实现。文章从分析原因入手,通过解决造成此情况的根本问题,提出了基于Flash Video技术SCORM运行时环境支持流式视频点播实现方案,较好实现了SCORM运行时环境对流式视频点播的支持。文中还介绍了实现方案的具体优势与局限性。是SCORM运行时环境对流式视频点播的支持相关技术的较全面介绍。 相似文献
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The 3rd generation partnership project (3GPP) has defined the protocols and codecs for implementing media streaming services over packet-switched 3G mobile networks. The specification is based on IETF RFCs on audio/video transport. It also adds new features to achieve better adaptation to the mobile network environment. In this paper, we propose an algorithm for handover detection and fast buffer refill that is based on the existing feedback and signaling mechanisms. The proposed algorithm refills the receiver buffer at a faster pace during a limited time frame after a hard handover is detected in order to achieve higher video quality. 相似文献
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黄雄 《广东职业技术师范学院学报》2014,(11):20-25
目前主流的视频传输技术是流媒体技术,但是视频传输过程中都需要依赖Flash插件,视频传输过程更需要选择流媒体格式,或者安装播放器的客户端.HTML5的Video标签能够支持WEB浏览器摆脱Flash插件的使用,并丰富浏览器端的网页应用.基于流媒体技术中的RTP,RTSP传输协议,本文构造了支持HTML5的视频播放器,该播放器具有视频的传输、控制、离线存储和播放等功能. 相似文献
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INTRODUCTION With the emergence of wireless technology, various multimedia services, e.g., audio and/or video, are reaching us today through portable devices any- time, anywhere and even more increasingly accessi- ble in the near future. High quality video streaming over wireless IP is one of the most attractive applica- tions by ongoing deployment of wireless local area network (WLAN) hotspots and even powerful Wi- MAX mobile coverage. However, the present Internet is not providing a… 相似文献
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电大在线平台的视频课件主要有录像视频和三分屏视频两种.本文结合任务技术匹配理论、教育目标概念、信息传播相关理论,通过实验研究比较这两种视频课件的学习效果.研究结果表明录像视频课件比三分屏视频课件能更好地实现记忆、领会、应用三种教育目标,即录像视频课件比三分屏视频课件有更好的学习效果. 相似文献
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José Miguel Santos Espino María Dolores Afonso Suárez Juan José González-Henríquez 《Technology, Pedagogy and Education》2020,29(2):147-162
ABSTRACTThis study explores the use of digital videos in education, from the perspective of the teacher as an agent of technological integration. Secondary and university teachers were surveyed in a region-wide case study. Three topics were specifically surveyed: common uses of digital video in teaching, instructor self-production of educational videos, and preferences in common presentation formats (chalk-and-talk, screencast, PowerPoint, demonstration and whiteboard writing). Results show that secondary teachers make more use of digital video and are more innovative than university teachers. Video self-production is scarce, though respondents declare a positive attitude, with time constraints and technical qualification as main reported obstacles. Preferences in video presentation formats reveal notable differences between secondary and university teachers for some formats. Preferences are also moderately influenced by the teacher’s knowledge field, and by experience with ICT and video production. 相似文献
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鉴于传统流媒体教育平台的局限性,提出了一种基于P2P架构的流媒体远程视频教学平台的构建方案,并对P2P流媒体平台的特点和优势进行了研究,分析比较了两种流媒体架构平台的性能,阐释了基于P2P流媒体技术的远程视频教学系统具有的技术特点和优势,并在广域网范围内进行了实验测试,在实验中P2P效果明显。 相似文献