e2gLite Free Expert System Shell - Pros and Cons, Demonstrations

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Building and Using Expert Systems: a Mini-Course Introducing the e2gLite Expert System Shell

Module 1: Is this technology for you?

Unlike the Web server-based WebESIE shell used to implement most eXpertise2Go demonstrations, e2gLite is a Java applet that is embedded in a Web page and downloaded from the Web server by the user’s browser. The applet loads a knowledge base from the server and then runs entirely on the browser. The advantages and disadvantages of this client-centered approach include:

Advantages:

Accessibility. Because e2gLite’s applet and knowledge bases are files downloaded to the user’s browser, expert systems can be delivered from virtually any Web host including the free/very inexpensive hosts often provided to Internet Service Provider (ISP) customers or to students by their educational institutions. These sites often do not allow the use of server-side Java, Java Server Pages (JSP), Active Server Pages (ASP), Common Gateway Interface (CGI) or other server-side program execution environments.

Ease of use and flexibility. A Java applet is almost as easy to embed in a Web page as a graphical image, and may be inserted in a cell in an HTML table to facilitate flexible page formatting and integration of expert system capabilities with other content.

Disadvantages:

Startup time. The e2gLite applet will be downloaded to the browser when the first Web page referencing the applet is loaded. With a typical modem connection to the Web, this takes about ten seconds. The download time for the knowledge base takes additional time that depends on the size of the file. Once downloaded, the applet may be used with different knowledge bases on multiple pages or many times on the same page and will not be reloaded until the browser is reloaded. Because of the startup time issue, e2gLite is most appropriate for small-scale expert systems containing less than 100 rules.

Knowledge base design visibility. An e2gLite knowledge base is a text file read from the Web server by the Java applet. It is therefore a public document, so you cannot keep the design of your knowledge base confidential.

Browser compatibility considerations. When an applet runs in a browser, it uses the Java Virtual Machine (JVM) installed with the browser. Microsoft's announced exclusion of a JVM from the version of Internet Explorer installed with Windows XP will cause all Web pages using applets to fail when accessed with that browser unless the user downloads and installs a JVM. If the potential user’s browser is not configured to allow the use of Java applets, e2gLite will not run. Different browsers and browser versions implement slightly different (and mostly obsolete) versions of the JVM. e2gLite works best with the 1.1.x JVM versions that install with recent (4.x +) versions of Netscape and Internet Explorer. There are minor inconsistencies (that shouldn’t affect results) in the applet’s operation among browsers and browser versions.

You may want to begin using e2gLite by running some samples from the eXpertise2Go.com Web site. The "end-user" mode displays only the applet window and is the mode used to deliver expert systems for public access. In the "developer" (debug) mode, a debug window will open after the knowledge base is loaded. This window displays error messages, traces the activities performed during a consultation and offers optional diagnostic information about the knowledge base. Details of debug mode facilities are introduced in Module 4 and described in detail in the Reference.

Graduate school admissions demonstration: end-user mode

Graduate school admissions demonstration: developer (debug) mode

Auto diagnosis demonstration: end-user mode

Auto diagnosis demonstration: developer (debug) mode

Localized auto diagnosis demonstration: end-user mode (en Français) (Machine translation was used to produce this demonstration. We apologize in advance to native French speaking users!) The procedure for delivering e2gLite expert systems in languages other than English is described in Module 7.

Fuzzy logic sport selection demonstration: end-user mode (Thanks to John Roche of the School of Multimedia and Information Technology, Southern Cross University Lismore, Australia and his students Sana Hosseini and Tristan Smith for this example. A brief introduction to fuzzy logic is included in the Inference Methods and Uncertainty tutorial.)

Fuzzy logic sport selection demonstration: developer (debug) mode

If, after running these demos, you'd like to learn more about about this technology, you need to proceed to Module 2 to see how to obtain the e2gLite software and demonstration knowledge bases and install these components on your own Web site.

[Index][Module 2][Module 3][Module 4][Module 5][Module 6][Module 7][Module 8][Reference]

Advantages:

	Accessibility. Because e2gLite’s applet and knowledge bases are files downloaded to the user’s browser, expert systems can be delivered from virtually any Web host including the free/very inexpensive hosts often provided to Internet Service Provider (ISP) customers or to students by their educational institutions. These sites often do not allow the use of server-side Java, Java Server Pages (JSP), Active Server Pages (ASP), Common Gateway Interface (CGI) or other server-side program execution environments.
	Ease of use and flexibility. A Java applet is almost as easy to embed in a Web page as a graphical image, and may be inserted in a cell in an HTML table to facilitate flexible page formatting and integration of expert system capabilities with other content.

Disadvantages:

	Startup time. The e2gLite applet will be downloaded to the browser when the first Web page referencing the applet is loaded. With a typical modem connection to the Web, this takes about ten seconds. The download time for the knowledge base takes additional time that depends on the size of the file. Once downloaded, the applet may be used with different knowledge bases on multiple pages or many times on the same page and will not be reloaded until the browser is reloaded. Because of the startup time issue, e2gLite is most appropriate for small-scale expert systems containing less than 100 rules.
	Knowledge base design visibility. An e2gLite knowledge base is a text file read from the Web server by the Java applet. It is therefore a public document, so you cannot keep the design of your knowledge base confidential.
	Browser compatibility considerations. When an applet runs in a browser, it uses the Java Virtual Machine (JVM) installed with the browser. Microsoft's announced exclusion of a JVM from the version of Internet Explorer installed with Windows XP will cause all Web pages using applets to fail when accessed with that browser unless the user downloads and installs a JVM. If the potential user’s browser is not configured to allow the use of Java applets, e2gLite will not run. Different browsers and browser versions implement slightly different (and mostly obsolete) versions of the JVM. e2gLite works best with the 1.1.x JVM versions that install with recent (4.x +) versions of Netscape and Internet Explorer. There are minor inconsistencies (that shouldn’t affect results) in the applet’s operation among browsers and browser versions.