Re: OWL-S process preconditions

Drew,

I agree that XML literals are certainly the right syntactical approach 
for representing preconditions and effects. The way I read your example 
is that you want to let an expression say what language it is in and 
then use that content language to describe preconditions and effects 
(similar to what KQML used to do). Is that correct? If so, I'm very much 
in favour of the flexibility this provides.

The difficult part then will be to define the formal semantics of 
preconditions and effects. How are you planning to do that? Are you 
thinking of an approach similar to reification in RDF?


Gerhard
 

Drew McDermott wrote:

> The current frontrunner is to represent conditions as literals, either 
> XML literals or some other kind. An attribute of a condition is its 
> logical language. Example:
>
>   <owls:AtomicProcess>
>      <owls:hasPrecondition>
>	<owls:Expression expressionLanguage="&swrl;#SWRL"
>	                 rdf:parseType="Literal">
>           <ruleml:body rdf:parseType="Collection">
>	      <swrl:individualPropertyAtom>
>		 <swrl:propertyPredicate rdf:resource="creditCardAuth"/>
>		 <swrl:argument1 rdf:resource="#cc"/>
>		 <swrl:argument2 rdf:datatype="&xsd;#string">Yes</swrl:argument2>
>	      </swrl:individualPropertyAtom>
>           </ruleml:body rdf:parseType="Collection">
>	</owls:Expression>
>      </owls:hasPrecondition>
>   </owls:AtomicProcess>
>
>The reason to use literals is to "hide" the RDF from the main RDF
>parser.  What a knowledgeable Owl-S parser must actually do is
>re-parse the hidden RDF chunks later, when it's possible to do
>appropriate substitutions.  In the example above, the
>individualPropertyAtom is not really about the variable "#cc"; it's
>about the _value_ of that variable in some context.  When that value
>is available, the RDF can be reprocessed to yield a statement about
>the authorization status of that credit card.
>
>  
>

Received on Tuesday, 22 June 2004 05:58:02 UTC