OO jDREW Top-Down Demo Application Instructions

1. Type Definition
If your knowledge base makes use of the type system, you must define the type hierarchy for it. This is done in RDFS, using the rdfs:Class and rdfs:subClassOf elements. This RDFS document can be entered in the text area provided on the Type Definition tab.
Note that the following types are predefined:

Thing - The top of the type lattice - every type will inherit from this type
String - A type to represent strings - this is used by the built-in relations
Numeric - A base type for numeric values
Integer - A type to represent integer numbers - this is a sub-type of Numeric. This is used by the built-in relations
Real - A type to represent real numbers - this is a sub-type of Numeric. This is used by the built-in relations
Nothing - The bottom of the type lattice - this type inherits from every type. This is used as the artificial lower bound when two types have now lower bound. You cannot create a type that is a sub-type of Nothing.

Once you have entered the rdfs to define your types press the Load Type Information button to parse the type information.

If your knowledge base does not make use of types you do not need to do anything on the Type Definition tab.

2. Knowledge Base

The knowledge base (rulebase) can be entered in either RuleML 0.88 (with rest tags) XML format, or the POSL syntax. On the Knowledge Base tab of the demo application window select the correct format with the radio buttons at the bottom of the tab, and then enter the knowledge base in the text area provided on the Knowledge Base tab, you should be able to copy and paste from other applications.

Once you have entered your knowledge base click the Parse Knowledge Base button to parse and load your knowledge base. When you parse a knowledge base all previous known clauses are erased.

If your knowledge base makes use of the type system you should complete step one before doing this step.

3. Querying the Knowledge Base

Before issuing the first query the knowledge base and type definitions must be parsed and loaded into memory as described in steps 2 and 1.

To issue a query, enter your query (in POSL syntax only) in the text area at the top of the query tab and click the Issue Query button. If there are result(s) to your query the instantiated solution tree will be displayed in Solution tree on the Output tab, and any variable bindings will be displayed in Variable Bindings: table. If there are more possible solutions to your query, the Next Solution will be enabled, by clicking on the Next Solution button the next solution will be displayed as just described. All output for the Top-Down Application is in POSL syntax, even if the knowledge base is in RuleML.

Last Updated:
   May 6, 2005

By:
   Marcel Ball