| RE: [higgins-dev] Representing Metadata in the Higgins Ontology |
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Paul,
My predict-o-meter is way off. I assumed you would have answered with a proposal to add a higgins:metadata, which when present on a DigitalSubject would be digital subject metadata, and when present on an Attribute would be attribute metadata (likewise for SubjectRelationship).
One potential problem with the proposals below is what happens if we add new properties (we'd have to update our definition(s) to say "...and which is neither "higgins:attribute" nor "higgins:relationship nor "higgins:xyz"."
Regarding higgins:uniqueIdentifier: At the Raleigh face to face, my impression was that there would be an attribute with a higgins-specified type used to hold the cuid, and the IDAS APIs would in effect provide a "shortcut" method (IDigitalSubject.getUniqueID) to access it. So I guess I expected the higgins.owl to contain an attribute definition looking something like this:
<owl:ObjectProperty rdf:about="#uniqueIdentifier">
<rdfs:range rdf:resource="#StringSimpleAttribute"/> <rdfs:domain rdf:resource="#DigitalSubject"/> <rdfs:subPropertyOf rdf:resource="#attribute"/> </owl:ObjectProperty> (I probably screwed that up) and assumed higgins.DigitalSubject would specify a minCardinality of 1 for this attribute
On relationships: IdAS has the notion of things that have relationships (IContext and IDigitalSubject). Relationships always have a type, metadata, and a related object. <aside>I guess in the owl, the type is just the relationship type (so a parentOf relationship would be a subclass of relationship I suppose). Also, I guess the thing representing the "related object" in owl is just whatever we decide it is (for a SubjectRelationship , it's the higgins:contextURI nor higgins:subjectCUID, for a ContextRelationship, it's just the higgins:contextURI).</aside> If one sublcasses SubjectRelationship (to makes something like a ParentRelationship) and adds more properties to that sublcass, would we automatically assume all the added properties are metadata? I suppose so.
Jim
>>> "Paul Trevithick" <paul@xxxxxxxxxxxxxxxxx> 10/17/06 2:13 PM >>> > > It doesn't look like we're labeling anything specifically as metadata. We > just define a new object property, create a class for it's range, set it's > domain(s) and that appears to be it. This seems to require that the > implementor of an IdAS CP will have to have a table that says ... for > example, "timeSpan" is metadata, not an attribute. Is this correct? You're right that the word "metadata" isn't explicitly used anywhere in higgins.owl. The semantics of this word are defined by the IdAS API/CPI. >From the RDF/OWL perspective, we could create a consistent (with IdAS) definition of higgins:Attribute metadata as: any RDF property whose domain is higgins:Attribute and which is neither "higgins:complexValue" nor "higgins:simpleValue". And we could define higgins:DigitalSubject metadata as: any RDF property whose domain is higgins:DigitalSubject and which is neither "higgins:attribute" nor "higgins:relationship" BTW, I'd have to ask Jim if he thought we should also exclude "higgins:uniqueIdentifier" or not. And we could define higgins:SubjectRelationship metadata as: any RDF property whose domain is higgins:SubjectRelationship and which is neither higgins:contextURI nor higgins:subjectCUID > > I'm trying to define some metadata for a derived ontology we're working on > and I feel like, especially for derived ontologies, we'll need to > specificall call things out as metadata. Of course, I may just be out in > left field here, so let me give the specific example ... of course, this > may just be an extension of the Relationship vs. Attribute discussion but > hey, I'm trying to make progress where I can ... Let me know what you think of the above. If that doesn't work for you, you can define your own concept (RDF property) in your sub-ontology and create sub-properties from that. And if that doesn't work, there are other options... > > I want to define an object property, as far as I can tell, as a > subProperty of a &higgins;relationship. You can certainly define a sub-property of higgins:relationship, but I would have thought that its range would be a subclass, C, of higgins:SubjectRelationship. And I would have thought that it is instances of C that are the places where you can hang all kinds of RDF properties (much like our postalAddress example). BTW, on a related note. I'm still open to changing higgins.owl such that the higgins:SubjectRelationship is a sub-class of higgins:Attribute as we discussed last Thursday. Doing so would, through inheritance, give SubjectRelationship (optional) "metadata" properties such as source, timeSpan, etc. Would that also help? I want my object property to have > metadata and, as per the IdAS API, a relationship can have metadata. > That's good. What do I need to do in my ontology to define this metadata, > identify it as metadata, and restrict it to the object property I desire? Let me know what you think of what I've written above, before I try to answer further. _______________________________________________ higgins-dev mailing list higgins-dev@xxxxxxxxxxx https://dev.eclipse.org/mailman/listinfo/higgins-dev |