Default Logic Simulation - Online-Help 

This applet should visualize the method for finding extensions of a given default theory (comprising definite knowledge plus a number of default assumptions) presented in the lecture "Wissensbasierte Systeme" at the TU Vienna. This lecture is obligatory for students of computer science.

System requirements:

For running this applet all you need is a Java 1.1 capable browser, e.g. Netscape 4.06 or higher. We have tested it under Solaris and Windows95/NT using Netscape.
Description of the applet: After loading you can choose an example from a list (partly examples from the lecture, partly taken from old exams):


By clicking the button  you can open this Help-Site.

After you have selected an example, the sets W (the initial knowledge) and D (a set of Defaults), which represent the chosen default theory, are shown.
The button  remains inactive until you have chosen an example. Clicking this button you get a short description of the selected example.
The button  also remains inacative until you select an example, it opens the simulation window, which shows how candidates for extensions are calculated.

After the candidates for extensions have been calculated, a table showing the list of candidates to be tested is displayed in the applet window, e.g.:

You can select one of the canditates for testing either by selecting it in this list   or by simply clicking on it in the table. The testing of a candidate is again shown in an own simulation window, that visualizes how you can check if a candidate really is an extension or not.

Simulation window

 The calculation of possible candidates and testing of a single candidate is shown in an own window. Here you can see the most important elements of the user interface: