- From: Cayzer, Steve <Steve.Cayzer@hp.com>
- Date: Fri, 6 Feb 2004 08:46:37 -0000
- To: "'Charles McCathieNevile'" <charles@w3.org>, "Cayzer, Steve" <Steve.Cayzer@hp.com>
- Cc: "'Miles, AJ (Alistair) '" <A.J.Miles@rl.ac.uk>, "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>
That's my reading of (b) Al: We allow three methods for uniquely identifying a concept: a. The URI for the concept. b. A combination of the concept's prefLabel and the URI of the thesaurus to which it belongs. c. A combination of the concept's externalID and the URI of the thesaurus to which it belongs. > -----Original Message----- > From: Charles McCathieNevile [mailto:charles@w3.org] > Sent: 06 February 2004 01:05 > To: Steve Cayzer > Cc: Miles, AJ (Alistair) ; public-esw-thes@w3.org > Subject: Re: Blank nodes for concepts. > > > > Is there really any reason you can't have two concepts with > the same prefLabel? > > as I understand it > > <Concept> > <prefLabel>Bar</prefLabel> > <altLabel>Baz</altLabel> > </Concept> > <Concept> > <prefLabel>Bar</prefLabel> > <altLabel>Foo</altLabel> > </Concept> > > doesn't give you any right to infer that the two balnk nodes > are the same (this would be that case if you made prefLabel > map 1:1 with concepts but I think that's a bad idea anyway). > > Looking at user scenarios, there is an obvious cost to two > concepts having the same preferred label - whenever you want > to classify something by that label you need to be clear > which one you mean. On the benefit side, you might well have > a term that commonly refers to a couple of different > concepts, and want to be easily able to look for things with > the preferred Label. > > "accessible" is the example that springs to mind in my > everyday stuff. I suspect in putting vocbularies together > it's also useful. > > Cheers > > Chaals > > On Thu, 5 Feb 2004, Steve Cayzer wrote: > > > > >Makes sense to me. > > > >Might be worth adding an explanation to one of the docos, both > >technical (as > >below) and non technical (implication - you can't add a new > concept with the > >same prefLabel as another concept in the same thesaurus) > > > >Cheers > > > >Steve > >----- Original Message ----- > >From: "Miles, AJ (Alistair) " <A.J.Miles@rl.ac.uk> > >To: <public-esw-thes@w3.org> > >Sent: Thursday, February 05, 2004 6:03 PM > >Subject: Blank nodes for concepts. > > > > > >> > >> Hi, > >> > >> A couple of people have picked up that in the examples in the > >> documents > >[1] > >> [2] [3] I've encoded concepts as blank nodes, without URIs. This > >> email addresses why I chose to do that. > >> > >> My thinking is as follows. We allow three methods for uniquely > >identifying > >> a concept: > >> > >> a. The URI for the concept. > >> b. A combination of the concept's prefLabel and the URI of the > >> thesaurus to which it belongs. c. A combination of the concept's > >> externalID and the URI of the thesaurus to which it belongs. > >> > >> So, the following are all valid globally unique concept > declarations: > >> ---- > >> <soks:Concept rdf:about="http://foo.com/examplethes/aconcept"/> > >> ---- > >> <soks:Concept> > >> <soks:prefLabel>Bangers & Mash</soks:prefLabel> <rdfs:isDefinedBy > >> rdf:resource="http://foo.com/examplethes"/> > >> </soks:Concept> > >> ---- > >> <soks:Concept> > >> <soks:externalID>A00456</soks:externalID> > >> <rdfs:isDefinedBy rdf:resource="http://foo.com/examplethes"/> > >> </soks:Concept> > >> ---- > >> > >> I'll get to why in a minute. > >> > >> I also then thought, rather than giving every concept and > ><rdfs:isDefinedBy> > >> property to indicate membership of some conceptual scheme, why not > >> allow people to subclass the <soks:Concept> class? > >> > >> So, for example, you could define the class: > >> ---- > >> <rdfs:Class rdf:about="http://foo.com/thesaurus/Concept"> > >> <rdfs:subClassOf > >> > rdf:resource="http://www.w3c.rl.ac.uk/2003/11/21-skos-core#Concept"/> > >> <rdfs:comment>This is the class of all concepts from the foo.com > >> thesaurus.</rdfs:comment> </rdfs:Class> > >> ---- > >> Which would then allow globally unique concept > declarations such as the > >> following: > >> ---- > >> <foo:Concept> > >> <soks:prefLabel>Bangers & Mash</soks:prefLabel> > >> </foo:Concept> > >> ---- > >> <foo:Concept> > >> <soks:externalID>A00456</soks:externalID> > >> </foo:Concept> > >> ---- > >> > >> OK, so why bother? > >> > >> 1. It makes for better-looking RDF encodings (this is a serious > >> point, as it may help reduce the uptake hurdle - how many > times have > >> you heard > >people > >> groan that RDF looks like gobbledegook because of all the > URIs? Also > >> remember many potential users are from totally non sem-web > >> environments, e.g. english heritage. RDF is a new and complicated > >> beast to them.) > >> > >> 2. It may not be appropriate to give a URI to a concept > that is part > >> of some thesaurus that has been defined by an authority > outside the > >> semantic web world. So until the authority itself gives its own > >> concepts URIs, we can still make statements about them using > >> reference-by-description. > >> > >> On the down side ... > >> > >> 1. Someone has to write a bit of reasoning code to equate > all blank > >> nodes with the same prefLabel/rdfs:isDefinedBy property > values, and > >> run it over the data before publishing it. > >> > >> Where I fall on the matter: in the short term use URIs to > identify > >> concepts, so can work in a world without any reasoning > required. In > >> the slightly longer term look into allowing the blank-node style > >> encodings, > >and > >> support the little bit of reasoning required with some code. > >> > >> What does everyone think? > >> > >> Al. > >> > >> > >> [1] http://www.w3c.rl.ac.uk/SWAD/deliverables/8.1.html > >> [2] http://www.w3c.rl.ac.uk/SWAD/deliverables/8.3.html > >> [3] http://www.w3c.rl.ac.uk/SWAD/deliverables/8.4.html > >> > >> CCLRC - Rutherford Appleton Laboratory > >> Building R1 Room 1.60 > >> Fermi Avenue > >> Chilton > >> Didcot > >> Oxfordshire OX11 0QX > >> United Kingdom > >> > >> Email: a.j.miles@rl.ac.uk > >> Telephone: +44 (0)1235 445440 > >> > >> > > > > Charles McCathieNevile http://www.w3.org/People/Charles > tel: +61 409 134 136 > SWAD-E http://www.w3.org/2001/sw/Europe fax(france): > +33 4 92 38 78 22 > Post: 21 Mitchell street, FOOTSCRAY Vic 3011, Australia or > W3C, 2004 Route des Lucioles, 06902 Sophia Antipolis Cedex, France >
Received on Friday, 6 February 2004 03:48:12 UTC