【最新word论文】VIRTUAL PROGRAMMING LAB FOR ON-LINE DISTANCE LEARNING （上）【计算机网络专业论文】.doc

1VIRTUAL PROGRAMMING LAB FOR ON-LINE DISTANCE LEARNING £¨ÉÏ£©AbstractIn this paper, we describe the design of the WebVL system, a Web-based Virtual Programming Lab for on-line distance learning. The underlying setting is a collection of computers hosting education and programming software. Students use personal computers at home to access over the Internet one of the Lab servers, which is typically located at a school. The Lab server performs functions to accommodate the various requests from the student, ranging from downloading software from the school lab servers, working through interactive demonstration and tutorial sessions, and submitting a program for execution on a Lab computer using specified software package.The collection of computers forms a virtual programming laboratory because the machines can be located in different buildings and even at different campuses. It facilitates resource sharing among different schools and overcomes the limit of geographical distances. The WebVL system design includes an agent-based client side functions and interface, the structuring of Lab servers, the mechanisms to locate user requested software packages / services and to present various forms of data and information, and the interfaces to various education and programming software packages. Technologies such as virtual reality, Java Applets and Servlets, mobile agent, XML, and Web/HTTP servers are used to implement the underlying mechanisms and facilities of the virtual Lab, such as software resource locating and interfacing, real-time interaction, and information presentation. Using these technologies allows the system to achieve high-performance, scalability, and disconnected operation through reduction in network bandwidth and delay, load balancing, and code mobility.1. INTRODUCTIONDuring the last several years, e-learning has emerged as one of the fastest-moving trends in education and is booming. Thanks to the widespread access to the Internet, on-line education is enabling students and professionals to learn from afar, keeping pace with technological and managerial changes. Thousands of technical and management courses are now being offered by universities, for-profit professional development centers, and industry training facilities worldwide [Ube00]. Underpinning the teaching and learning over the Web, the global 2connectivity of the Internet and a new generation of hardware and software applications have equipped distance learning with new methods of delivery. The convenience of Web education made distance learning effective and flexible, even in the absence of face-to-face interactions in the classroom. Nowadays, students who take courses on-line can access the courses whenever and wherever convenient. They can download the lecture note from the Web, communicate with each other and their instructor through e-mail, and took exams by responding to questions on computer screens. Although several e-learning software supporting on-line lecturing and tutoring have been found popular [Web, Wbt, Lea] and many works have been done in providing Web-based learning and teaching [Ibr94, Swi97, Shi00, Ube00], there has been not many reports on providing students convenient on-line access to programming facilities available in computer labs. A few work can be found which develops either ad hoc or special purpose Web programming facilities [Sha97, McI98, Row99]. In this paper, we describe the design of the WebVL system, a generic Web-based Virtual Programming Lab for on-line distance learning. The powerful features of the WWW, especially the integration of most widespread Internet protocols, allow us to design software to facilitate the access to almost existing resources available on the Internet in an integrated fashion [Ibr94]. In addition to navigation through hypermedia documents, using the remote access capability of the Internet technology, various software programs can be executed remotely through WWW. In our design, the underlying setting is a collection of computers hosting education and programming software. Students use personal computers at home to access over the Internet one of the Lab servers, which is typically located at a school. The Lab server performs functions to accommodate the various requests from the student, ranging from downloading software from the school lab servers, working through interactive demonstration and tutorial sessions, and submitting a program for execution on a Lab computer using specified software package.The collection of computers forms a virtual programming laboratory because the machines can be located in different buildings and even at different campuses. It facilitates resource sharing among different schools and overcomes the limit of geographical distances. The WebVL system design includes an agent-based client side functions and interface, the structuring of Lab servers, the mechanisms to locate user requested software packages / services and to present vario。