交互式多媒体网络教学系统的研究与实现
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摘要
随着教学改革的深入和计算机技术与应用的发展,多媒体网络教学成为传统教学模式的发展方向。近几年,国内外涌现了大量的多媒体教学软件,大多数都具有比较类似的特征,如音/视频交互、共享白板、教学广播、具有特定的用户角色和权限控制等。
该文针对多媒体网络教学交互性的特点,参考了多种系统模型,设计了交互式多媒体网络教学系统的构架,实现了多媒体网络教室的功能,并实现了一个交互式多媒体网络教学应用平台,包括上层公共服务、底层网络通信协议和信息传输平台。该系统成功地应用于实际教学,充分地验证了该系统的实用性。
该文重点分析并实现了网络传输,具体应用和应用状态控制3个层次的5个关键技术,为交互式多媒体网络教学系统的实现提供了很好的技术支持。针对网络传输的问题,给出混合组播的实现方法,相比单一的传输方式(单播、组播),提高了网络传输的效率,降低了网络负载;针对NAT网关限制,给出端口映射的实现方法,通过应用平台,在数据传输层摆脱了NAT网关的限制,解决了内部专用Intranet的用户无法参与交互式应用的问题;针对屏幕传输问题,给出动态屏幕图像截取快速算法,相比整屏截取,提高了屏幕图像传输效率,使教学过程更加流畅;应用DirectShow流媒体开发包,实现音视频实时交互;针对交互控制问题,给出发言权控制策略,保障多媒体网络教学过程中交互的有序性和可靠性。
相比现有的多媒体网络教学软件,该系统能够实现负载均衡,适应较大规模应用;基于混合组播实现自适应传输,提高了网络传输效率;提出动态屏幕截取快速算法,提高了屏幕图像传输效率。
该文最后将智能手机及无线技术应用于多媒体网络教学中,体现了该系统的灵活性与扩展性。该文针对异构设备开发的特点,应用了MVC架构的设计思想,主要实现了基于Symbian OS的智能手机的音视频播放及录制功能。
With the in-depth educational reform and the development of computer technology, the multimedia network education directs the traditional education. In recent years, a lot of multimedia education software appear in the world, and most have relatively similar characteristics, such as audio, video, whiteboard sharing, teaching broadcasting, the role and right control of a specific user, and so on.Aiming at the interactive feather of multimedia network education, this paper consults some system models, and introduces interactive multimedia network education system's structural models. This paper realizes the functions of multimedia network education system, and realizes the application platform of a interactive multimedia network education system, which defines the upper public services, the lower transmission interface, the message tranfer platform. This system successfully applies to the actual teaching and gets full certification by the utility.This paper has focus on some key technologys in three layers which include network transmission, application and application state control to provide a good technical support for this system. This paper brings forward mixed multicast to revolve the network transmission problem, and enhances the efficiency of the network transmission, reduce network load;This paper brings forward port mapping to cross through the NAT gateway, and resolves the problem that the internal users can't join the specialized interactive applications;This paper brings forward dynamic screen images capture rapid algorithm, and enhances screen images transmission efficiency, make teaching process more fluid;This paper uses DirectShow multimedia development kits to achieve real-time interactive audio and video;This paper brings forward floor control policy to protect the world of multimedia network teaching process orderly and reliability.Compared to the existing multimedia network teaching software, this system can achieve load balance and server more applications;and brings forward mixed multicast to enhance the efficiency of the network transmission;and brings forward dynamic screen images capture rapid algorithm to enhance screen images transmission efficiency.At last, by applying smart phone and wireless technology to multimedia teaching, the flexibility and expansibility of this system is embodied. This paper aims at the feather of development on isomerization unit equipment, and designs the mobile system with the MVC
framework. The main achievement is realizing a player and recorder of audio and video in the smart phones based on Symbian OS.
该文针对多媒体网络教学交互性的特点,参考了多种系统模型,设计了交互式多媒体网络教学系统的构架,实现了多媒体网络教室的功能,并实现了一个交互式多媒体网络教学应用平台,包括上层公共服务、底层网络通信协议和信息传输平台。该系统成功地应用于实际教学,充分地验证了该系统的实用性。
该文重点分析并实现了网络传输,具体应用和应用状态控制3个层次的5个关键技术,为交互式多媒体网络教学系统的实现提供了很好的技术支持。针对网络传输的问题,给出混合组播的实现方法,相比单一的传输方式(单播、组播),提高了网络传输的效率,降低了网络负载;针对NAT网关限制,给出端口映射的实现方法,通过应用平台,在数据传输层摆脱了NAT网关的限制,解决了内部专用Intranet的用户无法参与交互式应用的问题;针对屏幕传输问题,给出动态屏幕图像截取快速算法,相比整屏截取,提高了屏幕图像传输效率,使教学过程更加流畅;应用DirectShow流媒体开发包,实现音视频实时交互;针对交互控制问题,给出发言权控制策略,保障多媒体网络教学过程中交互的有序性和可靠性。
相比现有的多媒体网络教学软件,该系统能够实现负载均衡,适应较大规模应用;基于混合组播实现自适应传输,提高了网络传输效率;提出动态屏幕截取快速算法,提高了屏幕图像传输效率。
该文最后将智能手机及无线技术应用于多媒体网络教学中,体现了该系统的灵活性与扩展性。该文针对异构设备开发的特点,应用了MVC架构的设计思想,主要实现了基于Symbian OS的智能手机的音视频播放及录制功能。
With the in-depth educational reform and the development of computer technology, the multimedia network education directs the traditional education. In recent years, a lot of multimedia education software appear in the world, and most have relatively similar characteristics, such as audio, video, whiteboard sharing, teaching broadcasting, the role and right control of a specific user, and so on.Aiming at the interactive feather of multimedia network education, this paper consults some system models, and introduces interactive multimedia network education system's structural models. This paper realizes the functions of multimedia network education system, and realizes the application platform of a interactive multimedia network education system, which defines the upper public services, the lower transmission interface, the message tranfer platform. This system successfully applies to the actual teaching and gets full certification by the utility.This paper has focus on some key technologys in three layers which include network transmission, application and application state control to provide a good technical support for this system. This paper brings forward mixed multicast to revolve the network transmission problem, and enhances the efficiency of the network transmission, reduce network load;This paper brings forward port mapping to cross through the NAT gateway, and resolves the problem that the internal users can't join the specialized interactive applications;This paper brings forward dynamic screen images capture rapid algorithm, and enhances screen images transmission efficiency, make teaching process more fluid;This paper uses DirectShow multimedia development kits to achieve real-time interactive audio and video;This paper brings forward floor control policy to protect the world of multimedia network teaching process orderly and reliability.Compared to the existing multimedia network teaching software, this system can achieve load balance and server more applications;and brings forward mixed multicast to enhance the efficiency of the network transmission;and brings forward dynamic screen images capture rapid algorithm to enhance screen images transmission efficiency.At last, by applying smart phone and wireless technology to multimedia teaching, the flexibility and expansibility of this system is embodied. This paper aims at the feather of development on isomerization unit equipment, and designs the mobile system with the MVC
framework. The main achievement is realizing a player and recorder of audio and video in the smart phones based on Symbian OS.
引文
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[5] 计文平,郭宝龙,丁贵广.新一代视频压缩编码国际标准的研究.计算机应用与软件,2004,21(2):60-62
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[7] Schulrinne H, Casner S, Frederick R, et aI. RTP: A transport protocol for real-time applications. RFC1889,1996: 3-38
[8] 史美林,向勇,徐光信等.计算机支持的协同工作:理论与应用.北京:电子工业出版社,2000
[9] Garlan D, Shaw M. An introduction to software architecture. Technique Report, Carnegie Mellon University, 1994: 1-3
[10] Perry D E. Software engineering and software architecture. Beijing: Electronic Industry Press, 2000
[11] The boeing company-defense and space group. STARS conceptual framework for reuse processes. STARS program technical report, Boston, 1994: 106-112
[12] Vestal S. A cursory overview and comparison of four architecture description languages, Honeywell Technology Center Technical Report, Chicago, 1993: 1-9
[13] IEEE Glossary of software engineering terminology. IEEE, 1998: 990
[14] Gacek C, Ahd-Allah A, Clark B K, et al. In proceedings of the Ist international workshop on architecture for software systems. New York: ACM Press, 1995
[15] 杨志,邢思杰.IP组播技术初探.http:/WWW.knowsky.com/9930/html,2000
[16] Francis P. Extending' the multicast internet architecture. White Paper, 1999: 1-5
[17] Semeria C, Mauler T. Introduction to multicast routing: Internet Draft. lnternet Engineering Task Force (IETF), 1999
[18] 陆绍飞,杨贯中,刘关琴等.基丁主干网信息可扩展的应用层组播.计算机工程与应用,2005,27:134-137
[19] Mimura N, Nakauchi K, Morikawa H, et al. RelayCast: A middleware for application-level multicast services. IEEE/ACM International Symposium on Cluster Computing and the Grid, 2003: 637-646
[20] Chu Y, Rao S, Zhang H. A case for end system multicast. Proceedings of ACM Sigmetrics, 2000: 59-63
[21] 吴洪才,殷人昆,贺思德.屏幕捕获技术在多媒体教学中的实现探讨.计算机工程,2003,29(13):195-197
[22] 郝智泉,吕汉兴,程臻.基于局域网的视频图像传输与监视系统.计算机应用研究,2003,06:61-63
[23] 宋玲,陈燕,基于DirectShow实现网络音视频实时发送和回放.电子技术应用,2006,01:67-70
[24] 刘涛.基于DirectShow的流媒体解码和回放.http://www, yesky, com/20021210/1643686_1, shtml, 2002
[25] Desmond Keegan. The future of learning: From eLearning to mLearning.http://learning, ericsson, net/mlearning2/project_one/book, html, 2002
[26] Maurer S S. A survey of embedded systems programming languages. IEEE Potentials, 2002, 21(2): 30-34
[27] Ann Marie Rincon, William R Lee, Michael Slattery. The changing landscape of system-on-a-chip design. Custom Integrated Circuits, 1999: 16-19
[28] 章立生,韩承德.SOC芯片设计方法及标准化.计算机研究与发展,2002,39(1):1-8
[29] Mrva M. Reuse factors in embedded systems design. Computer, 1997, 30 (8): 93-95
[30] Wolf W. Household hints for embedded systems designers. Computer, 2002, 35(5): 106-108
[31] Koopman P. Embedded system security. Computer, 2004, 37(7): 95-97
[32] Topalis E, Orphanos G, Koubias S, et al. A generic network management architecture targeted to support home automation networks and home internet connectivity. IEEE Transactioa, 2000, 461(20): 44-51
[33] Bradley J, Rhodes, Nelson Minar, et al. Wearable computing meets ubiquitous computing: Reapting the best of both worlds. Proceedings of the International Symposium on Wearable Computers, 1999: 33-35
[34] Palm. palm Software and PDhs: Developer. http://www.palmsource, com/developers, 2001
[35] Microsoft. Handheld Devices from Microsoft Windows Mobile.http://www.microsoft, com/windowsmobile/default, mspx, 2003
[36] Symbian. Crystal version 6.0 edition for C++ symbian developers library.http://www. Symbian. com, 2001
[37] Tasker M. Professional symbian programming. NY: Wrox Press, 2000
[38] Symbian. Symbian OS V6. x overview, http://www. Symbian. com, 2002
[2] Deshpande S G, Hwang J N. A real-time interactive virtual classroom multimedia distance learning system. IEEE Transactions on Multimedia, 2001, 3(4): 105-108
[3] Deshpande S G, Hwang J N. An interactive virtual classroom-multimedia distance learning system. New York: International Workshop on Multimedia Signal Processing, 1999
[4] 余兆明,李晓飞,陈来春.MPEG标准及其应用.北京:北京邮电大学出版社,2002
[5] 计文平,郭宝龙,丁贵广.新一代视频压缩编码国际标准的研究.计算机应用与软件,2004,21(2):60-62
[6] W Richard Stevens. TCP/IP illustrated volumel: The protocols. American: Addison Wesley, 1998
[7] Schulrinne H, Casner S, Frederick R, et aI. RTP: A transport protocol for real-time applications. RFC1889,1996: 3-38
[8] 史美林,向勇,徐光信等.计算机支持的协同工作:理论与应用.北京:电子工业出版社,2000
[9] Garlan D, Shaw M. An introduction to software architecture. Technique Report, Carnegie Mellon University, 1994: 1-3
[10] Perry D E. Software engineering and software architecture. Beijing: Electronic Industry Press, 2000
[11] The boeing company-defense and space group. STARS conceptual framework for reuse processes. STARS program technical report, Boston, 1994: 106-112
[12] Vestal S. A cursory overview and comparison of four architecture description languages, Honeywell Technology Center Technical Report, Chicago, 1993: 1-9
[13] IEEE Glossary of software engineering terminology. IEEE, 1998: 990
[14] Gacek C, Ahd-Allah A, Clark B K, et al. In proceedings of the Ist international workshop on architecture for software systems. New York: ACM Press, 1995
[15] 杨志,邢思杰.IP组播技术初探.http:/WWW.knowsky.com/9930/html,2000
[16] Francis P. Extending' the multicast internet architecture. White Paper, 1999: 1-5
[17] Semeria C, Mauler T. Introduction to multicast routing: Internet Draft. lnternet Engineering Task Force (IETF), 1999
[18] 陆绍飞,杨贯中,刘关琴等.基丁主干网信息可扩展的应用层组播.计算机工程与应用,2005,27:134-137
[19] Mimura N, Nakauchi K, Morikawa H, et al. RelayCast: A middleware for application-level multicast services. IEEE/ACM International Symposium on Cluster Computing and the Grid, 2003: 637-646
[20] Chu Y, Rao S, Zhang H. A case for end system multicast. Proceedings of ACM Sigmetrics, 2000: 59-63
[21] 吴洪才,殷人昆,贺思德.屏幕捕获技术在多媒体教学中的实现探讨.计算机工程,2003,29(13):195-197
[22] 郝智泉,吕汉兴,程臻.基于局域网的视频图像传输与监视系统.计算机应用研究,2003,06:61-63
[23] 宋玲,陈燕,基于DirectShow实现网络音视频实时发送和回放.电子技术应用,2006,01:67-70
[24] 刘涛.基于DirectShow的流媒体解码和回放.http://www, yesky, com/20021210/1643686_1, shtml, 2002
[25] Desmond Keegan. The future of learning: From eLearning to mLearning.http://learning, ericsson, net/mlearning2/project_one/book, html, 2002
[26] Maurer S S. A survey of embedded systems programming languages. IEEE Potentials, 2002, 21(2): 30-34
[27] Ann Marie Rincon, William R Lee, Michael Slattery. The changing landscape of system-on-a-chip design. Custom Integrated Circuits, 1999: 16-19
[28] 章立生,韩承德.SOC芯片设计方法及标准化.计算机研究与发展,2002,39(1):1-8
[29] Mrva M. Reuse factors in embedded systems design. Computer, 1997, 30 (8): 93-95
[30] Wolf W. Household hints for embedded systems designers. Computer, 2002, 35(5): 106-108
[31] Koopman P. Embedded system security. Computer, 2004, 37(7): 95-97
[32] Topalis E, Orphanos G, Koubias S, et al. A generic network management architecture targeted to support home automation networks and home internet connectivity. IEEE Transactioa, 2000, 461(20): 44-51
[33] Bradley J, Rhodes, Nelson Minar, et al. Wearable computing meets ubiquitous computing: Reapting the best of both worlds. Proceedings of the International Symposium on Wearable Computers, 1999: 33-35
[34] Palm. palm Software and PDhs: Developer. http://www.palmsource, com/developers, 2001
[35] Microsoft. Handheld Devices from Microsoft Windows Mobile.http://www.microsoft, com/windowsmobile/default, mspx, 2003
[36] Symbian. Crystal version 6.0 edition for C++ symbian developers library.http://www. Symbian. com, 2001
[37] Tasker M. Professional symbian programming. NY: Wrox Press, 2000
[38] Symbian. Symbian OS V6. x overview, http://www. Symbian. com, 2002
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