远程教育教学支持系统的研究与实现
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摘要
基于Internet的远程教育教学系统是现代远程教育的方向，支持网上教学的远程教育平台在其中扮演着重要的角色，它的性能和功能直接决定了远程教育的教学质量、教学手段、学习效果。本系统是一个基于J2EE平台的，综合采用JSP／Javabeans，applet、Java反射机制、JDBC等Java相关技术开发的远程教学支持系统。
系统的开发建立在Web服务器、应用服务器和数据库服务器的多层架构上。采用多层结构的方式使得系统具有很强的伸缩性、通用性、兼容性和可操作性，每一层能够专注于特定的角色和功能。
系统通过Web方式完成用户与系统的交互，采用JSP与JavaBeans相结合的方式实现数据信息的访问，使得程序代码的开发效率和质量提高、开发周期缩短、减少了后期的维护工作量。
本教学支持系统实现了对基本的远程教学活动的支持，实现实时交流子系统、自主学习、答疑讨论、公告板系统等多个模块。解决了网络环境下实施远程教学过程中的教学和交流两个主要问题。
教学系统通过多种方式实现教师和学生、学生和学生之间的交流。并在系统中实现一个实时交流子系统解决网络环境下教师和学生实时答疑的问题。该子系统的实现是采用Java反射机制，设计和实现了一个通用的服务器，它可以实现绝大多数基于Socket的网络服务，实时答疑的各项功能就是在通用服务器的支持下实现的具体服务。采用Java反射机制可以把可能变化的部分分离出来，由程序动态加载那部分实现。这样大大减少了程序的耦合性，从而提高软件的复用性，有利于教学系统以后的功能扩展。
教学支持系统采用视／音频流的方式解决网络环境下的教学问题。采用RealNetworks公司的流媒体方案解决流媒体格式的课件发布和播放问题；在本教学系统中用播放器来发布多媒体课件，这样的方式加快了课件的开发速度；并设计和实现了一个课件制作模块，用SMIL标记语言并结合Real播放器的功能，实现通过多种媒体形式的交互表达教学内容的目的。
System of distance education is the base of distance education. Its performance and functions directly decide the teaching quality and studying effect . The system is distance education supported system based on J2EE three-tier structure ,which applys JSP/Java component technology, applet,Java reflection ,JDBC and so on.
The system employs J2EE three-tier based structure.The implementation of multi-tier structure enables the system to have distinguished quality of flexibility, currency and compatibility.
Users interact on the system via Web.The system employs the technology of JSP and JavaBeans to access data,which shortens the cycle of system development and reduces the maintenance work
The teaching system mainly resolves two questions ,real-time commucation and teaching by Network.
This system supplys many methods by which users can communicate with each others. A subsystem of real-time communication gives support to teachers and students' real-time discussion.The subsystem uses Java reflection to implement a univeral server,which can help the future funcaition's extensibility .
The teaching system adopts a way of video and audio streaming to support the distance teaching in the circummstance of network.lt applys the solution of RealNetworks company's stream media , uses media player to play courseware and uses smil and RealOne player's performance to combine different kinds of courseware.
系统的开发建立在Web服务器、应用服务器和数据库服务器的多层架构上。采用多层结构的方式使得系统具有很强的伸缩性、通用性、兼容性和可操作性，每一层能够专注于特定的角色和功能。
系统通过Web方式完成用户与系统的交互，采用JSP与JavaBeans相结合的方式实现数据信息的访问，使得程序代码的开发效率和质量提高、开发周期缩短、减少了后期的维护工作量。
本教学支持系统实现了对基本的远程教学活动的支持，实现实时交流子系统、自主学习、答疑讨论、公告板系统等多个模块。解决了网络环境下实施远程教学过程中的教学和交流两个主要问题。
教学系统通过多种方式实现教师和学生、学生和学生之间的交流。并在系统中实现一个实时交流子系统解决网络环境下教师和学生实时答疑的问题。该子系统的实现是采用Java反射机制，设计和实现了一个通用的服务器，它可以实现绝大多数基于Socket的网络服务，实时答疑的各项功能就是在通用服务器的支持下实现的具体服务。采用Java反射机制可以把可能变化的部分分离出来，由程序动态加载那部分实现。这样大大减少了程序的耦合性，从而提高软件的复用性，有利于教学系统以后的功能扩展。
教学支持系统采用视／音频流的方式解决网络环境下的教学问题。采用RealNetworks公司的流媒体方案解决流媒体格式的课件发布和播放问题；在本教学系统中用播放器来发布多媒体课件，这样的方式加快了课件的开发速度；并设计和实现了一个课件制作模块，用SMIL标记语言并结合Real播放器的功能，实现通过多种媒体形式的交互表达教学内容的目的。
System of distance education is the base of distance education. Its performance and functions directly decide the teaching quality and studying effect . The system is distance education supported system based on J2EE three-tier structure ,which applys JSP/Java component technology, applet,Java reflection ,JDBC and so on.
The system employs J2EE three-tier based structure.The implementation of multi-tier structure enables the system to have distinguished quality of flexibility, currency and compatibility.
Users interact on the system via Web.The system employs the technology of JSP and JavaBeans to access data,which shortens the cycle of system development and reduces the maintenance work
The teaching system mainly resolves two questions ,real-time commucation and teaching by Network.
This system supplys many methods by which users can communicate with each others. A subsystem of real-time communication gives support to teachers and students' real-time discussion.The subsystem uses Java reflection to implement a univeral server,which can help the future funcaition's extensibility .
The teaching system adopts a way of video and audio streaming to support the distance teaching in the circummstance of network.lt applys the solution of RealNetworks company's stream media , uses media player to play courseware and uses smil and RealOne player's performance to combine different kinds of courseware.
引文
[1] 《现代远程教育的特点及其发展》
[2] 《我国现代远程教育的现状与问题》蒋华林，重庆交通学院学报，2002．3
[3] 《J2EE技术内幕》Joseph J. Bambara Paul R. Allen等著，机械工业出版社，2002，6
[4] 《流媒体技术大全》张丽，中国青年出版社，2001，11
[5] http://www. chinameal.com/ 蓝宇视频媒体应用中心
[6] Real Networks: http://www.realnetworks.com/
[7] Smil Basics, Document of RealNetworks, Inc. 2002, [online] available URL: http://serv ic e. real. com/help/library/guides/productiongiq/HTM L/htmfiles/smiiintr. htm
[8] An Overview of Windows Media 9 Series, Microsoft Corporation. 2003,URL: http://www.microsoft.com/windows/windowsmedia/technologies/overview. aspx
[9] http://msdn.microsoft.com/library/default.asp/url=/library/en-us/wmsrvsdk/htm/wmsserverhtmltime.asp
[10] Java Reflection, Dr. Dobb's Journal January 1998
[11] Using Java Reflection, Glen McCluskey January 1998, [online]. Available URL: http://developer.java.sun.com/developer/technicalArticles/ALT/Reflection/
[12] Microsoft Corporation, The component object model specification, Version 0.9,October 24, 1995[online]. Available URL: http://WWW.microsoft.com/oledev/(1995)
[13] WillTracz, Confessions of a Used Program Sales man-Institutionalizing Software Reuse. Addison-Weslty Publishing Co. New York, NY, April 1995
[14] 《JSP结构模型与应用分析》徐冰 李启炎 朱倩，计算机应用研究，2001，10
[15] 《Servlet和JSP概述》MaHy Hall[美]著，邓英材 孟杰 孙建春 译，人民邮电出版社，2001，10
[16] Applets, Document of Sun Microsystems, Inc., 2002, [online] Available URL: http://java.sun.com/applets/
[17] Java编程思想(第2版)，Bruce Eckel，机械工业出版社，2002
[18] Java Socket Tutorial. [online] Available URL: http://www.ccs.neu.edu/home/kenb/
1335/socket_tut.html.
[19] Computer Networks 3rd Ed, Andrew S. Tanenbaum, 清华大学出版社(英文影印版)
[20] Java ~(TM)2 Platform, Standard Edition, v1.3.1 AP1 Sp(?)cification. [online] Available URL: http://java.sun.com/j2se/1.3/docs/api/
[21] 最新Java 2核心技术卷1：原理(原书第5版)，Cay S.Horstmann Gary Comell，机械工业出版社，2002
[22] 《设计模式》李英军 马晓星 蔡敏 刘建中 译，机械工业出版社，2002，8
[23] Practical Object—Oriented Design with UML，清华大学出版社(英文影印版)
[24] Real Networks Production Guide, Chapter 12, Layout, RealNetworks, Inc, 2002. Avalable Online:http://service.real.com/help/library/guides/realone/ProductionGuide/HTML/realpgd.htm.?page=htmfiles/linking.htm%23276831
[25] Synchronized Multimedia Integration Language (SMIL 2.0), W3C Recommendation 07 August 2001, Available Online: http://www.w3.org/TR/smil20/
[26] Real Networks Production Guide, Chapter 15, Hyperlinks, ReaINetworks, Inc, 2002. Avalable Online: http://service.real.com/help/library/guides/realone/ProductionGuide/HTML/realpgd.htm?page=htmfiles/linking.htm%23182991
[2] 《我国现代远程教育的现状与问题》蒋华林，重庆交通学院学报，2002．3
[3] 《J2EE技术内幕》Joseph J. Bambara Paul R. Allen等著，机械工业出版社，2002，6
[4] 《流媒体技术大全》张丽，中国青年出版社，2001，11
[5] http://www. chinameal.com/ 蓝宇视频媒体应用中心
[6] Real Networks: http://www.realnetworks.com/
[7] Smil Basics, Document of RealNetworks, Inc. 2002, [online] available URL: http://serv ic e. real. com/help/library/guides/productiongiq/HTM L/htmfiles/smiiintr. htm
[8] An Overview of Windows Media 9 Series, Microsoft Corporation. 2003,URL: http://www.microsoft.com/windows/windowsmedia/technologies/overview. aspx
[9] http://msdn.microsoft.com/library/default.asp/url=/library/en-us/wmsrvsdk/htm/wmsserverhtmltime.asp
[10] Java Reflection, Dr. Dobb's Journal January 1998
[11] Using Java Reflection, Glen McCluskey January 1998, [online]. Available URL: http://developer.java.sun.com/developer/technicalArticles/ALT/Reflection/
[12] Microsoft Corporation, The component object model specification, Version 0.9,October 24, 1995[online]. Available URL: http://WWW.microsoft.com/oledev/(1995)
[13] WillTracz, Confessions of a Used Program Sales man-Institutionalizing Software Reuse. Addison-Weslty Publishing Co. New York, NY, April 1995
[14] 《JSP结构模型与应用分析》徐冰 李启炎 朱倩，计算机应用研究，2001，10
[15] 《Servlet和JSP概述》MaHy Hall[美]著，邓英材 孟杰 孙建春 译，人民邮电出版社，2001，10
[16] Applets, Document of Sun Microsystems, Inc., 2002, [online] Available URL: http://java.sun.com/applets/
[17] Java编程思想(第2版)，Bruce Eckel，机械工业出版社，2002
[18] Java Socket Tutorial. [online] Available URL: http://www.ccs.neu.edu/home/kenb/
1335/socket_tut.html.
[19] Computer Networks 3rd Ed, Andrew S. Tanenbaum, 清华大学出版社(英文影印版)
[20] Java ~(TM)2 Platform, Standard Edition, v1.3.1 AP1 Sp(?)cification. [online] Available URL: http://java.sun.com/j2se/1.3/docs/api/
[21] 最新Java 2核心技术卷1：原理(原书第5版)，Cay S.Horstmann Gary Comell，机械工业出版社，2002
[22] 《设计模式》李英军 马晓星 蔡敏 刘建中 译，机械工业出版社，2002，8
[23] Practical Object—Oriented Design with UML，清华大学出版社(英文影印版)
[24] Real Networks Production Guide, Chapter 12, Layout, RealNetworks, Inc, 2002. Avalable Online:http://service.real.com/help/library/guides/realone/ProductionGuide/HTML/realpgd.htm.?page=htmfiles/linking.htm%23276831
[25] Synchronized Multimedia Integration Language (SMIL 2.0), W3C Recommendation 07 August 2001, Available Online: http://www.w3.org/TR/smil20/
[26] Real Networks Production Guide, Chapter 15, Hyperlinks, ReaINetworks, Inc, 2002. Avalable Online: http://service.real.com/help/library/guides/realone/ProductionGuide/HTML/realpgd.htm?page=htmfiles/linking.htm%23182991