校园网屏幕广播教学系统的设计与实现
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摘要
近年来,随着计算机应用技术的迅速发展与普遍应用,以网络和多媒体技术为基础的网络教育逐渐改变着传统的教育模式。网络教育技术使得教育资源得到共享和优化,它扩大了教师的授课面,为求知者提供了丰富的获取知识的途径,极大地缓解了迅速增长的知识需求与匮乏的教学资源之间的矛盾,已经成为现代教育体系中不可缺少的重要部分。因此实现一个高效率、稳定、延时低、可交互的网络教学系统对于推动网络教育的发展具有十分重要的意义。
校园网屏幕广播教学系统是一种具有视频会议特征的实时教学系统,实时性主要体现在教师机的电脑屏幕、教师视频和教师语音三种多媒体信息实时发布到学生端上。通过本系统教师能建立在线网络课堂,学生能够通过校园网络登录进入进来,使得课堂不必限制于传统意义上的物理教室范围,从而拓宽了教师的授课面。
本文首先调查当前的网络教学系统的现状,阐述了网络教育系统的功能和特点,分析了现阶段网络教学系统的应用范围局限性,给出了以现阶段常见校园网络为基础的基于组播树的多媒体数据通信模型,并以此模型为基础设计实现了屏幕广播教学系统。在设计实现的过程中,综合对比了当前主流的多媒体技术,选择了目前先进、高效的解决方案对系统进行了实现。最后,本文对整个工作进行了总结,提出了系统的改进意见。
During the last few years, with the rapid development of applying technology in computer science, network teaching based on network and multimedia technology is gradually changing the traditional teaching style. Network teaching technology enables sharing and optimizing of learning resources, it extends the number of students that teachers work on, it provides learners a way that helps them to obtain rich knowledge, it extremely alleviates the contradiction between rapid increasing knowledge requirement and lacking of teaching resources. Now network teaching is an important component in modern teaching hierarchy. So implementing an efficient, stable, low delaying and interactive network teaching system has a crucial important meaning.
Campus network screen broadcast teaching system is a kind of video conference like system with real-time feature. Because multimedia information such as desktop screen, video and sound generated at teacher's computer when a teacher is holding an active class sends to student's computer in time. By using our system teacher can create network active class, students can join in the class created by their teacher via campus network, so traditional classes has no teaching location limitation any more, it extremely extends the number of taught students.
In this paper we analyze functions and features of current popular teaching system at the beginning and point out their limitation. After that we propose a multimedia data transmission model based on application layer multicasting technology, and we design and implement a screen broadcast teaching system based on the transmission model. During the process of designing and implementing the system, we choose efficient solutions by comparing current common used multimedia technologies. Finally, we make a conclusion that look forward to future edition of the system.
校园网屏幕广播教学系统是一种具有视频会议特征的实时教学系统,实时性主要体现在教师机的电脑屏幕、教师视频和教师语音三种多媒体信息实时发布到学生端上。通过本系统教师能建立在线网络课堂,学生能够通过校园网络登录进入进来,使得课堂不必限制于传统意义上的物理教室范围,从而拓宽了教师的授课面。
本文首先调查当前的网络教学系统的现状,阐述了网络教育系统的功能和特点,分析了现阶段网络教学系统的应用范围局限性,给出了以现阶段常见校园网络为基础的基于组播树的多媒体数据通信模型,并以此模型为基础设计实现了屏幕广播教学系统。在设计实现的过程中,综合对比了当前主流的多媒体技术,选择了目前先进、高效的解决方案对系统进行了实现。最后,本文对整个工作进行了总结,提出了系统的改进意见。
During the last few years, with the rapid development of applying technology in computer science, network teaching based on network and multimedia technology is gradually changing the traditional teaching style. Network teaching technology enables sharing and optimizing of learning resources, it extends the number of students that teachers work on, it provides learners a way that helps them to obtain rich knowledge, it extremely alleviates the contradiction between rapid increasing knowledge requirement and lacking of teaching resources. Now network teaching is an important component in modern teaching hierarchy. So implementing an efficient, stable, low delaying and interactive network teaching system has a crucial important meaning.
Campus network screen broadcast teaching system is a kind of video conference like system with real-time feature. Because multimedia information such as desktop screen, video and sound generated at teacher's computer when a teacher is holding an active class sends to student's computer in time. By using our system teacher can create network active class, students can join in the class created by their teacher via campus network, so traditional classes has no teaching location limitation any more, it extremely extends the number of taught students.
In this paper we analyze functions and features of current popular teaching system at the beginning and point out their limitation. After that we propose a multimedia data transmission model based on application layer multicasting technology, and we design and implement a screen broadcast teaching system based on the transmission model. During the process of designing and implementing the system, we choose efficient solutions by comparing current common used multimedia technologies. Finally, we make a conclusion that look forward to future edition of the system.
引文
1 李小美.基于网络学习共同体学习的研究[D].东北师范大学硕士论文.2006:13-15.
2 蓝斌.现代远程教育环境下教学模式重构.中国远程教育.2005(05).
3 晓文,王莹.教学策略.高等教育出版社出版.2000:27-33.
4 David Jonassen et. al. Constructivism and Computer-Mediated Communication in Distance Education. The American Journal of DistanceEducation.Vol.9 No.2, 1995.
5 虞万荣.用 WebCT 构建远程教学系统.计算机工程.2000/S1.
6 陈群.Webct、Blackboard 平台的现状及挑战.软件导刊.2005(09).
7 王佳.现代远程教育教学模式的探讨.中国高教研究.2001(02).
8 刘源海.论优化多媒体教学信息系统与提高教学质量的关系.中国大学教学.2005(12).
9 王月娟 . 多媒体白板系统及其在远程教育中的应用 [D]. 大连理工大学硕士论文.2006:13-15.
10 Duc A. Tran, Kien A. Hua, Tai T. Do.A Peer-to-Peer Architecture for Media Streaming. IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 22, NO.1, JAN 2004.
11 Karl Aberer and Zoran Despotovic. Managing trust in a Peer-2-Peer information system. In Henrique Paques, Ling Liu, and David Grossman, editors, Proceedings of the Tenth International Conference on Information and Knowledge Management (CIKM-01), New York, ACM Press, November 5–10 2001:310-317.
12 An Zhang, Haifeng He, Zhiqun Deng. Stochastic fluid model for P2P content distribution networks. Autonomous Decentralized Systems, 2005:707–712.
13 Y.-H. Chu, S. G. Rao, and H. Zhang."A case for end system multicast" in Proc. ACM SIGMETRICS, 2000:1-12.
14 S. Banerjee, B. Bhattacharjee, and C. Kommareddy. Scalable application layer multicast. In Proc. ACM Sigcomm, August 2002.
15 Yang-hua Chu, Rao S.G., Seshan, S, Hui Zhang. A case for end system multicast.. IEEE Journal on Selected Areas in Communications. Volume 20, Issue 8, Oct.2002:1456-1471.
16 Y., Ansari M., Batra R., Jin W., Karabatis G., Krychiniak P., Rusinkiewicz M., Suardi L.Narada: An environment for specification and execution of multi-system applications, 1992. ICSI '92. Proceedings of the Second International Conference on Halabi.Systems Integration. 15-18 June 1992:680-690.
17 Waldvogel M, Mohandas R. Shi, S. efficient keyserver using ALMI. Tenth IEEE International Workshops on 20-22 June 2001:237–243.
18 李贝贝,黄锋.信息技术的兼容性分析——以软件业为例.中国工业经济.2003(07).
19 丘子隽.IP 组播与 P2P 协作分发体系的研究与设计[D].北京邮电大学硕士论文.2006:47-49.
20 Thamrin, A.H., Izumiyama, H., Kusumoto, H. PIM-SM cconfiguration and scalability on satellite unidirectional links. 2003 Symposium on Applications and the Internet Workshops. 27-31 Jan. 2003:27-30.
21 Hubenko, P.V., Jr., Raines, R.A., Temple, M.A., Mills, R.F., Saeger, M.D. Adaptation, modeling, and analysis of PIM-DM in a LEO satellite network environment. Aerospace Conference, 2006 IEEE 4-11 March 2006:9.
22 Ranjitkar, P.G., Suliman, I.M., Geil, P., Kuipers, M.M., Prasad, R. IP multicast implementation based on the multicast extensions to OSPF protocol. 2000 IEEE International Conference on Personal Wireless Communications. 17-20 Dec. 2000:484–489.
23 王伟. 距离矢量组播路由协议的分析与实现[D].西南交通大学硕士论文. 2005:47-52.
24 马凌霄.基于 P2P 网络的流媒体技术研究[D].浙江大学硕士论文.2005:31-33.
25 朱坤华.一个基于应用层的单源组播协议设计.微计算机信息.2006(25).
26 钟玉琢,向哲,沈洪.流媒体和视频服务器.清华大学出版社.2003.6.
27 胡泽,赵新梅编著.流媒体应用技术.中国广播电视出版社.2004.5.
28 Jeon W.J., Nahrstedt K. Peer-to-peer multimedia streaming and caching service. 2002 IEEE International Conference on Multimedia and Expo, Volume 2,2002:57-60.
29 高文,吴枫. MPEG-4 编码的现状和研究. 计算机研究与发展. 1999, 36(6): 641-652.
30 谭玉波.基于 Internet 的端到端视频传输控制研究[D].国防科学技术大学博士论文.2005:43-50.
31 黄军浩,毕笃彦,许悦雷,张明,王岩.基于 H.264 的多参考帧运动估计快速算法.计算机工程,2006,(12).
32 XVID library. http://www.xvid.org
33 张兵.基于多缓冲区实时音频采集和传输实现.计算机工程,2006(12).
34 梁飞蝶,李锦涛,史红周.虚拟网络计算(VNC)协议中的编码方法.计算机应用,2004,(06).
35 Kaplinsky K.V.VNC tight encoder-data compression for VNC.Modern Techniques and Technology, 2001. MTT 2001. Proceedings of the 7th International Scientific and Practical Conference of Students,Post-graduates and Young Scientists.26 Feb.-2 March 2001:155-157.
36 常永昌,冯新喜,王芳.一种远程控制软件的设计与实现.计算机应用.2003.3.
37 章照止.林须端.信息论与最优编码.上海科学技术出版社. 1993, 220-243.
38 Messom C. H.,Sen Gupta G.,Demidenko S.N.Hough Transform Run Length Encoding for Real-Time Image Processing.,IEEE Transactions on Instrumentation and Measurement. Volume 56, Issue 3, June 2007:962-967.
39 吴乐南编著.数据压缩的原理与应用.电子工业出版社.1995.
40 Tech Smith Screen Capture Codec. http://wiki.multimedia.cx/index.php?title=TechSmith_Screen_Capture_Codec.
41 Zlib library FAQ.http://www.zlib.net/zlib_faq.html.
42 Chongjia Peng,Yong Tang,Xianji Li,Chengjie Mao.The control and algorithm of audio dynamic buffer.The Sixth International Conference on Computer Supported Cooperative Work in Design. 2001 12-14 July 2001:143–145.
43 谭敏安,艾本仁,曹元大,张雪兰.一个负载自适应的实时音频播放算法.计算机工程.2006(14).
44 Ramabadran T.V., Gaitonde S.S. A tutorial on CRC computations. IEEE Micro 1988(8):62-74.
45 陆其明著.DirectShow 实务精选.科学出版社.2004.7:1-8.
46 Jeffrey Richter.Programming Application for Microsoft Windows.4th. Microsoft Press.1999:190-224.
47 李涛.基于 ACE 的并发编程模式和池式内存分配的研究.计算机工程与设计.2006(01).
2 蓝斌.现代远程教育环境下教学模式重构.中国远程教育.2005(05).
3 晓文,王莹.教学策略.高等教育出版社出版.2000:27-33.
4 David Jonassen et. al. Constructivism and Computer-Mediated Communication in Distance Education. The American Journal of DistanceEducation.Vol.9 No.2, 1995.
5 虞万荣.用 WebCT 构建远程教学系统.计算机工程.2000/S1.
6 陈群.Webct、Blackboard 平台的现状及挑战.软件导刊.2005(09).
7 王佳.现代远程教育教学模式的探讨.中国高教研究.2001(02).
8 刘源海.论优化多媒体教学信息系统与提高教学质量的关系.中国大学教学.2005(12).
9 王月娟 . 多媒体白板系统及其在远程教育中的应用 [D]. 大连理工大学硕士论文.2006:13-15.
10 Duc A. Tran, Kien A. Hua, Tai T. Do.A Peer-to-Peer Architecture for Media Streaming. IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 22, NO.1, JAN 2004.
11 Karl Aberer and Zoran Despotovic. Managing trust in a Peer-2-Peer information system. In Henrique Paques, Ling Liu, and David Grossman, editors, Proceedings of the Tenth International Conference on Information and Knowledge Management (CIKM-01), New York, ACM Press, November 5–10 2001:310-317.
12 An Zhang, Haifeng He, Zhiqun Deng. Stochastic fluid model for P2P content distribution networks. Autonomous Decentralized Systems, 2005:707–712.
13 Y.-H. Chu, S. G. Rao, and H. Zhang."A case for end system multicast" in Proc. ACM SIGMETRICS, 2000:1-12.
14 S. Banerjee, B. Bhattacharjee, and C. Kommareddy. Scalable application layer multicast. In Proc. ACM Sigcomm, August 2002.
15 Yang-hua Chu, Rao S.G., Seshan, S, Hui Zhang. A case for end system multicast.. IEEE Journal on Selected Areas in Communications. Volume 20, Issue 8, Oct.2002:1456-1471.
16 Y., Ansari M., Batra R., Jin W., Karabatis G., Krychiniak P., Rusinkiewicz M., Suardi L.Narada: An environment for specification and execution of multi-system applications, 1992. ICSI '92. Proceedings of the Second International Conference on Halabi.Systems Integration. 15-18 June 1992:680-690.
17 Waldvogel M, Mohandas R. Shi, S. efficient keyserver using ALMI. Tenth IEEE International Workshops on 20-22 June 2001:237–243.
18 李贝贝,黄锋.信息技术的兼容性分析——以软件业为例.中国工业经济.2003(07).
19 丘子隽.IP 组播与 P2P 协作分发体系的研究与设计[D].北京邮电大学硕士论文.2006:47-49.
20 Thamrin, A.H., Izumiyama, H., Kusumoto, H. PIM-SM cconfiguration and scalability on satellite unidirectional links. 2003 Symposium on Applications and the Internet Workshops. 27-31 Jan. 2003:27-30.
21 Hubenko, P.V., Jr., Raines, R.A., Temple, M.A., Mills, R.F., Saeger, M.D. Adaptation, modeling, and analysis of PIM-DM in a LEO satellite network environment. Aerospace Conference, 2006 IEEE 4-11 March 2006:9.
22 Ranjitkar, P.G., Suliman, I.M., Geil, P., Kuipers, M.M., Prasad, R. IP multicast implementation based on the multicast extensions to OSPF protocol. 2000 IEEE International Conference on Personal Wireless Communications. 17-20 Dec. 2000:484–489.
23 王伟. 距离矢量组播路由协议的分析与实现[D].西南交通大学硕士论文. 2005:47-52.
24 马凌霄.基于 P2P 网络的流媒体技术研究[D].浙江大学硕士论文.2005:31-33.
25 朱坤华.一个基于应用层的单源组播协议设计.微计算机信息.2006(25).
26 钟玉琢,向哲,沈洪.流媒体和视频服务器.清华大学出版社.2003.6.
27 胡泽,赵新梅编著.流媒体应用技术.中国广播电视出版社.2004.5.
28 Jeon W.J., Nahrstedt K. Peer-to-peer multimedia streaming and caching service. 2002 IEEE International Conference on Multimedia and Expo, Volume 2,2002:57-60.
29 高文,吴枫. MPEG-4 编码的现状和研究. 计算机研究与发展. 1999, 36(6): 641-652.
30 谭玉波.基于 Internet 的端到端视频传输控制研究[D].国防科学技术大学博士论文.2005:43-50.
31 黄军浩,毕笃彦,许悦雷,张明,王岩.基于 H.264 的多参考帧运动估计快速算法.计算机工程,2006,(12).
32 XVID library. http://www.xvid.org
33 张兵.基于多缓冲区实时音频采集和传输实现.计算机工程,2006(12).
34 梁飞蝶,李锦涛,史红周.虚拟网络计算(VNC)协议中的编码方法.计算机应用,2004,(06).
35 Kaplinsky K.V.VNC tight encoder-data compression for VNC.Modern Techniques and Technology, 2001. MTT 2001. Proceedings of the 7th International Scientific and Practical Conference of Students,Post-graduates and Young Scientists.26 Feb.-2 March 2001:155-157.
36 常永昌,冯新喜,王芳.一种远程控制软件的设计与实现.计算机应用.2003.3.
37 章照止.林须端.信息论与最优编码.上海科学技术出版社. 1993, 220-243.
38 Messom C. H.,Sen Gupta G.,Demidenko S.N.Hough Transform Run Length Encoding for Real-Time Image Processing.,IEEE Transactions on Instrumentation and Measurement. Volume 56, Issue 3, June 2007:962-967.
39 吴乐南编著.数据压缩的原理与应用.电子工业出版社.1995.
40 Tech Smith Screen Capture Codec. http://wiki.multimedia.cx/index.php?title=TechSmith_Screen_Capture_Codec.
41 Zlib library FAQ.http://www.zlib.net/zlib_faq.html.
42 Chongjia Peng,Yong Tang,Xianji Li,Chengjie Mao.The control and algorithm of audio dynamic buffer.The Sixth International Conference on Computer Supported Cooperative Work in Design. 2001 12-14 July 2001:143–145.
43 谭敏安,艾本仁,曹元大,张雪兰.一个负载自适应的实时音频播放算法.计算机工程.2006(14).
44 Ramabadran T.V., Gaitonde S.S. A tutorial on CRC computations. IEEE Micro 1988(8):62-74.
45 陆其明著.DirectShow 实务精选.科学出版社.2004.7:1-8.
46 Jeffrey Richter.Programming Application for Microsoft Windows.4th. Microsoft Press.1999:190-224.
47 李涛.基于 ACE 的并发编程模式和池式内存分配的研究.计算机工程与设计.2006(01).