Re: OWL-S process preconditions

Hi all, I've only been lurking here, but on this point I have a newbie
question: wouldn't reification be a better tool than reparsing of
literals? The amount of work for the implementations would be the same
but it would seem to me to be much cleaner from the data modeling point
of view - for instance when serialized as n-triples, the literal
approach would keep XML syntax intermixed with the n-triples, whereas
reification would have everything as n-triples.

Best regards,

                   Jacek Kopecky

                   Ph.D. student researcher
                   Digital Enterprise Research Institute
                   http://www.deri.org/




On Tue, 2004-06-22 at 11:58, Gerhard Wickler wrote:
> 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 07:38:31 UTC