ایجاد یک سیستم هوشمند با استفاده از فن آوری های اینترنت مدرن

This paper is a detailed case study of building Code Tutor, a Web-based intelligent tutoring system (ITS) in the domain of radio communications. It is ontologically founded and was built using CLIPS and Java-based expert system tools, latest integrated graphical CASE tools for software analysis and design, and Java servlets. In Code Tutor, Apache HTTP Server stores and serves static HTML pages, and Apache JServ Java package enables dynamic interpretation of user defined servlet classes and generation of active HTML pages. XML technology is used to generate files that Code Tutor uses to provide recommendations to the learners. Such a rich palette of integrated advanced technologies has greatly alleviated the system design and implementation, and has also led to interesting solutions of a number of problems common to many ITSs. The paper describes these solutions and useful design decisions, and discusses several practical issues related to architectures of intelligent Web-based applications.

Using current Internet technology to support learning in the classroom is recently getting much easier and much more feasible than it used to be. If a network of computers or workstations is available in the classroom, it is easy to install and use Apache, Orion, Tomcat, or another Web server on a dedicated server machine to distribute HTML pages generated statically or dynamically by an educational application. Client computers/workstations should only have an Internet browser. Hardware and software requirements for the client machines are minimal. We acquired experience with this technology when developing an intelligent tutoring system (ITS) called Code Tutor. Code Tutor is a small Web-based tutor designed for fast students’ briefing in the area of radio-communication. The learners are telecommunications college students. After they complete a course in radio-communication theory, they are supposed to exercise using expensive radio-station equipment. It is the teachers’ responsibility to ensure that the equipment is always in a good condition and that it is used appropriately. There is little time for checking each student's capabilities for independent practical work when the course is over and before the exercises begin. Code Tutor is used instead. The first version of Code Tutor has been actively used in the classroom since mid-2001. The teachers’ opinion is that it is very useful, and the students favor this kind of learning. However, the first version has some limitations. Its expert module is implemented as a rule-based expert system (ES) using an ES shell that was too old, without support for network-based applications. Also, due to these weaknesses of the shell the entire system is limited to ‘closed-world’ standalone applications, without connections and data interchange with the environment. These facts have motivated us to build a new version. The entire system is implemented in Java, using JBuilder 6 tool for developing Web-based and Java-based applications (Borland Corporation, 2001). The system's mid-layer is designed using Rational Rose tools for software analysis and design (Rational Corporation, 2001). The new Code Tutor integrates many different current technologies: CLIPS, a tool for building ES (CLIPS, 2002) is used to generate knowledge base files. Java-based ES shell Jess is used to interpret these files ( Sandia National Laboratories, 2002 and Friedman-Hill, 2002). Students communicate with the system through a standard Web browser. Java™ Servlet technology ( Sun Microsystems Corporation, 2001, Hall, 2001a and Hall, 2001b) is used to implement the system's interactions with the students. Apache server (The Apache Software Foundation, 2001a) is used to store static HTML pages. Apache JServ (The Apache Software Foundation, 2001b) is used to interpret the servlets. XML technology (The World-wide web consortium, 2001) is used to generate files that Code Tutor uses to provide recommendations to the students. When developing the new Code Tutor, our goal was not to further the research in Web-based ITS per se. Rather than that, we wanted to re-design and re-develop a working system, to make it work in a Web-based learning context, to make it intelligent at least to an extent, to have both the teachers and the learners actually use it, to document its design (made using current Web technologies), and to acquire valuable practical experience for further research and development of intelligent Web-based learning systems. Also, with the system's purpose (students’ briefing) in mind we wanted to keep the system small and simple. For the sake of all these goals, in the design of Web-based version of Code Tutor we have deliberately sacrificed some features that are certainly important in Web-based learning systems (e.g. adaptivity and integration of stand-alone domain service systems). In that sense, it should be noted that Code Tutor is actually Web-enabled and Web-ready, intended primarily for use in the classroom, rather than a full-fledged Web-based ITS built with the major goal of using it adaptively over the Web. The paper describes the new version of Code Tutor thoroughly. The next section briefly overviews related work of other authors relevant for the design and development of the new version, providing the context within which Code Tutor is best understood. Section 3 analyzes the system's use cases and shows its architecture. Design and implementation details are discussed in Section 4, while Section 5 specifically addresses Code Tutor's intelligent behavior. Section 6 covers important issues of Code Tutor's user interface design.

The present version of Code Tutor is developed using the latest technology. The major advantage of the new version of Code Tutor over the first one is its design flexibility. Big technological changes would not mean big changes in Code Tutor. The changes would only affect parts of the system. The object-oriented design contributes to the system extensibility. One of the first steps in further development of Code Tutor is to make it capable of learning by itself. This means that the teacher should be able to easily mark up the lessons (to mark up the keywords and give the names to the chapters) and put them in the knowledge base (to put the lesson file(s) in a selected directory and insert the file reference into the system accordingly). After that, the system should be able to interlink the teacher's input and generate the appropriate XML file(s). Also, the system should generate lesson templates and the appropriate forms based on the keywords. The marked-up facts in the lesson can be used to generate the rules. We discuss these ideas further in (Devedžić, 2002 and Devedžić, 2003). It should be stressed that, in order to use Code Tutor that way, the teacher should understand the domain and the basic principles of lesson marking, but is not required to understand details of the system design.