Re: How burdensome are the OWL restrictions on metadata?

Just curious: is system:IconClass an rdfs:subClassOf  or an instance of  rdfs:Class?

Suggested as follows:

system:IconClass rdf:type rdfs:Class  <!-- Should be modified  -->
system:hasIcon rdfs:domain system:IconClass
system:hasIcon rdfs:range xsd:string
chime:Aircraft rdf:type system:IconClass <!--Must be modified -->
chime:Aircraft  system:hasIcon "htttp:/localhost/.../aircraft.gif"


Yuzhong Qu


> At 11:11 -0800 4/4/03, Bob MacGregor wrote:
> >Our applications like to associate icons (gifs) with some
> >classes.  We implement this by having a class  IconClass that
> >is a subclass of rdfs:Class that has a slot 'hasIcon'.  For example:
> >
> >     system:IconClass rdfs:subClassOf  rdfs:Class
> >     rdfs:domain system:hasIcon system:IconClass
> >     rdfs:range system:hasIcon xsd:string
> >     chime:Aircraft rdfs:subClassOf  system:IconClass
> >     chime:Aircraft  system:hasIcon "htttp:/localhost/.../aircraft.gif"
> >
> >My question is, suppose we add some statements that include
> >some simple OWL-lite properties.  Does the combination of
> >our meta-level statements and the OWL-lite statements land
> >us into OWL-full, or are we OK?
> >
> >Cheers, Bob
> 
> welcome to OWL Full.  That said, there are some well know tricks for 
> dealing iwth this, in particular to create a distinguished instance 
> associated with each class - the problem is you must use an 
> "extralogical" trick for managing these, as they cannot be directly 
> associated with the class -- in some of the OWL Lite ontologies we've 
> done, we create a FooData class for every class Foo (with one 
> instance which is the "noninherited properties" as they would be in 
> LOOM), and then just have our tools know about that.  The OWL design 
> requires a strict separation of datatype and objectType which is, in 
> practice, one of the main differences between OWL Lite/DL and OWL 
> Full.  If we'd decided to include some standard mechanism in the OWL 
> design for this, I think we would have been better off (i.e. almost 
> every real world system needs some way to put some kind of property 
> on each class for managing things) - but there was no consensus in 
> the group as to how and whether to do this, so it didn't make it into 
> the langauge.  My group ended up going through a bunch of the papers 
> to appear in the DL Handbook, and discovered this distinguished 
> instance trick - so that's what we are using.
>   -JH
> p.s. to see this used in practice, see 
> http://www.mindswap.org/2003/CancerOntology/ which is in (nearly 
> correct) Owl Lite - needs a couple minor fixes to conform to last 
> minute WG changes.  It is the largest OWL Lite (and possibly largest 
> DAML or OWL) ontology composed to date - and it uses this trick 
> because each class needs to have a lot of individual/non-inherited 
> properties attached to it.
> -- 
> Professor James Hendler   hendler@cs.umd.edu
> Director, Semantic Web and Agent Technologies   301-405-2696
> Maryland Information and Network Dynamics Lab.   301-405-6707 (Fax)
> Univ of Maryland, College Park, MD 20742   240-731-3822 (Cell)
> http://www.cs.umd.edu/users/hendler
> 
> 
>

Received on Saturday, 5 April 2003 20:38:22 UTC