2011/8/20 Eric Scott <[email protected]>: > Thanks for your response. > > What's interesting is that so far I haven't asserted any equivalences at > all. I'm stuck at the point where I'm just trying to get a pulse from an > inference model built from the original TDB model + owl with no other > changes. > > Also, I'm able to get past this point with the RDFS reasoner, but as I > understand it, RDFS doesn't accommodate the owl equivalence relations. > >
How are you creating the reasoner? The default is for an RDFS reasoner, I believe, and you might be layering another one on top of that - or the OWL part itself might be harder to reason with than it looks... HTH, I. > On 08/20/2011 09:55 AM, Ignazio Palmisano wrote: >> >> 2011/8/20 Eric Scott<[email protected]>: >>> >>> I'm working on a project that explores integrating a fairly large pre- >>> (or >>> at least extra-) rdf ontology into RDF, the better to link to other >>> ontologies. >>> >>> Code has been written which translates the ontology written into >>> proprietary >>> format into rdf triples. It is stored in a TDB database, and amounts to >>> about 11 million statements. At this point almost all URIs are outside >>> the >>> standard RDF namespaces. It has it's own equivalent of subClassOf, for >>> example. We can query the triplestore effectively as-is. >>> >>> So in order to integrate this ontology with linked RDF data, it'd be nice >>> to >>> use things like owl:equivalentProperty to express equivalence between >>> say, >>> my:parentClass and rdfs:subClassOf. >>> >>> The first problem I'm encountering is that when I create a TDB model from >>> our 11M triples, then create an inference model integrated with an owl >>> reasoner, the system takes an intractably long time to load - even before >>> I >>> declare any relationships of any kind. >>> >>> Is this expected behavior? Is there a workaround? Would it be better to >>> rewrite the Proprietary->RDF translator to substitute say rdfs:subClassOf >>> for my:parentClass? >>> >> I'm not sure whether this comment is relevant, but it looks to me like >> yes, renaming from an arbitrary property to rdfs:subClassOf should >> help; I can imagine a few reasoners: >> a) having trouble understanding that these property assertions are not >> ABox axioms but TBox axioms (a bunch of tableaux optimizations cannot >> be applied safely when ABoxes exist, I believe, so reasoners would >> switch them off) >> b) having to reason about the equivalent properties as well: wherever >> an existing hierarchy is already in the ontology, your properties will >> be asserted as well; any domain/range would come into play as well, >> complicating things while the intention does not appear to be to >> change the interpretation >> c) reasoners may consider the subjects and objects of these properties >> as both classes (because they appear in triples with rdfs:subClassOf) >> and individuals (because they appear in triples with some other >> property); many of the reasoners I've had experience with start >> creaking at the joints with large number of individuals. >> >> Take this with a pinch of salt :-) renaming might pose other problems >> of which I'm not aware. >> HTH, >> I. >> >>> Any help appreciated. >>> >>> Regards, >>> > >
