- From: Benjamin Nowack <bnowack@appmosphere.com>
- Date: Sun, 30 Oct 2005 12:45:51 +0200
- To: "Hans Teijgeler" <hans.teijgeler@quicknet.nl>
- Cc: <semantic-web@w3.org>
On 30.10.2005 09:57:02, Hans Teijgeler wrote: >Would this be acceptable: > ><owl:Thing rdf:ID="PHO-387392"> > > <rdf:type >rdf:resource="http://www.iso15926.org/part2/2003-12#PhysicalObject"/> > ></owl:Thing> > >? >PS Then it is close to what the military do: name, rank and number. The >number of resulting triples seems to be the same as Frank's: > ><iso:PhysicalObject rdf:ID="PHO-387392"/> Using "owl:Thing" will lead to an additional #PHO-387392 rdf:type owl:Thing triple. If you don't do any reasoning based on the explicit "owl:Thing" typing, you may also just use <rdf:Description rdf:ID="PHO-387392"> <rdf:type rdf:resource="...#PhysicalObject" /> </rdf:Description> instead, which will result in a single triple only, "rdf:Description" is a syntactical construct that won't show up when the rdf/xml is parsed to plain triples. benjamin -- Benjamin Nowack Kruppstr. 100 45145 Essen, Germany http://www.bnode.org/ > > > >The "Thing" solution may have an advantage for me in that for individuals >that exist in space-time we have more than one typing to do, e.g.: > ><owl:Thing rdf:ID="PHO-387392"> > > <rdf:type >rdf:resource="http://www.iso15926.org/part2/2003-12#PhysicalObject"/> > > <rdf:type >rdf:resource="http://www.iso15926.org/part4/2005-10#MalePerson"/> > ></owl:Thing> > > > >(if PHO-387392 had been myCar, then it would read: > ><owl:Thing rdf:ID="PHO-387392"> > > <rdf:type >rdf:resource="http://www.iso15926.org/part2/2003-12#PhysicalObject"/> > > <rdf:type rdf:resource="http://www.iso15926.org/part4/2005-10#Car"/> > ></owl:Thing> > >) (where actually the identification of MalePerson and Car would read >something like COP-436327 and COIPO-438212, where COP=ClassOfPerson and >COIPO-ClassOfInanimatePhysicalObject) > > > > > > > >-----Original Message----- >From: Ivan Herman [mailto:ivan@w3.org] >Sent: Friday, October 28, 2005 3:08 PM >To: Hans Teijgeler >Cc: 'Frank Manola'; semantic-web@w3.org; Paap, Onno >Subject: Re: owl:Thing and RDF > >-------- Original Message -------- > >From: "Hans Teijgeler" <hans.teijgeler@quicknet.nl> > >To: "'Frank Manola'" <fmanola@acm.org> > >CC: "'Herman, Ivan'" <ivan@w3.org>, semantic-web@w3.org, "Paap, Onno" > ><onno.paap@ezzysurf.com> > >Subject: Re:owl:Thing and RDF > >Date: 28/10/2005 08:08 > > > >> Thanks, Frank, it is crystal clear to me now. > >> I hope Ivan agrees. > > > >Yep... this is, indeed, a question of taste and readability. For outside >user of > >a large RDF dataset using owl:Thing may make things (sic!) easier to read >and > >comprehend. I tend to avoid to much implicit knowledge in these syntactical > >choices, but that may be only me. > > > >Ivan > > > > > > > >> Hans > >> > >> =========================================== > >> > >> -----Original Message----- > >> From: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] On > >> Behalf Of Frank Manola > >> Sent: Thursday, October 27, 2005 11:36 PM > >> To: Hans Teijgeler > >> Cc: Herman, Ivan; semantic-web@w3.org > >> Subject: Re: owl:Thing and RDF > >> > >> > >> Hans-- > >> > >> See embedded comments below. > >> > >> Hans Teijgeler wrote: > >> > >>>Hi Frank and Ivan, > >>> > >>>Thank you for your responses! > >>> > >>>Two opinions, and this poor newbie must make a choice, where he had > >>>hoped for a solution: > >>> > >>>========================================== > >>>Ivan Herman wrote: > >>> > >>>I think that > >>> > >>>- if you use OWL Full, then owl:Thing is equivalent to rdf:Resource, you > >>>can't be more general than that:-) > >>> > >>>- if you use OWL DL or Lite, than you *have* to use owl:Thing, this is > >>>the way you identify individuals > >>> > >>>Ie: the safe bet is to use owl:Thing. You do not loose anything and, if > >>>at some point you have a smaller ontology that turns out DL or Lite, > >>>then you are all set. > >>> > >>>Just my personal opinion... > >>> > >>>Ivan > >>>========================================= > >>>Frank Manola wrote: > >>> > >>>Hi Hans-- > >>> > >>>I'm probably not the most reliable guide on OWL dialects, and I'm not > >>>sure I fully understand what you're doing. However, I don't see the > >>>need to use owl:Thing explicitly at all. My understanding is, if you > >>>create a user-defined OWL class, e.g., > >>> > >>><owl:Class rdf:ID="UserDefinedClass"/> > >>> > >>>or as a triple > >>> > >>>ex:UserDefinedClass rdf:type owl:Class . > >>> > >>>then UserDefinedClass is implicitly a subclass of owl:Thing; you need > >>>not say anything else. Then, if you create an instance myInstance and > >>>type it as a member of that OWL class, e.g., > >>> > >>>ex:myInstance rdf:type ex:UserDefinedClass . > >>> > >>>then myInstance is implicitly an instance of owl:Thing. This is true in > >>>any of the OWL dialects. > >>> > >>>--Frank > >>>============================================= > >>> > >>>Since both seem OK to me, the question arises why this is possible at > >>>all. Why has the SW been made so complex? Time for a clean-up? > >>> > >> > >> > >> I'm not sure I understand your concern. If the problem is that there > >> are equivalent ways to say the same thing in the SW, and you expect > >> there to be only one way, I don't think that's a very realistic > >> expectation if the SW is to get anywhere expressing reasonably complex > >> things. After all, there are certainly lots of ways to say the same > >> thing in English (or Dutch, or C), right? > >> > >>>Frank, if I would follow Ivan's advice, and typically use something > >>>explicit like: > >>> > >>> <owl:Thing rdf:ID="PHO-387392"/> > >>> <owl:Thing rdf:about="#PHO-387392"> > >>> <rdf:type > >>>rdf:resource="http://www.iso15926.org/part2/2003-12#PhysicalObject"/> > >>> <rdfs:label>Joe Blogg</rdfs:label> > >>> </owl:Thing> > >>> > >>>do you see any REAL disadvantage (other than the neglect of RDF)? Given > >>>the fact that we use OWL very rigorously by superimposing the ISO > >>>15926-2 data model, clearly and consistently distinguishing individuals > >>>from classes by using owl:Thing seems to fit in that rigor (or rigour, > >>>if you want). > >>> > >> > >> > >> Perhaps I'm missing something (or I didn't explain myself very well), > >> but I don't really understand the dilemma. Of course you can use the > >> syntax above (and I don't really think that it "neglects" RDF in any > >> awful way!). The only possible disadvantage I see is extra syntax. > >> There is an example in Section 3.1.2 of the OWL Guide > >> (http://www.w3.org/TR/owl-guide/) that seems to exactly parallel your > >> example. In that example, the Guide notes that, in defining an > >> instance, the syntax > >> > >> <Region rdf:ID="CentralCoastRegion" /> > >> > >> is exactly equivalent in meaning to > >> > >> <owl:Thing rdf:ID="CentralCoastRegion" /> > >> > >> <owl:Thing rdf:about="#CentralCoastRegion"> > >> <rdf:type rdf:resource="#Region"/> > >> </owl:Thing> > >> > >> Thus it seems to me that instead of writing your example > >> > >> <owl:Thing rdf:ID="PHO-387392"/> > >> > >> <owl:Thing rdf:about="#PHO-387392"> > >> <rdf:type > >> rdf:resource="http://www.iso15926.org/part2/2003-12#PhysicalObject"/> > >> <rdfs:label>Joe Blogg</rdfs:label> > >> </owl:Thing> > >> > >> you could write it instead as something like: > >> > >> <iso:PhysicalObject rdf:ID="PHO-387392"> > >> <rdfs:label>Joe Blogg</rdfs:label> > >> </iso:PhysicalObject> > >> > >> (where iso: is the namespace prefix that gives you the rest of the full > >> ISO URI). This is a typical RDF "typed node" abbreviation, and it works > >> the same way in OWL (as an RDF language). This is what I meant by > >> saying I didn't see the need to use owl:Thing explicitly. > >> > >> I'm assuming that http://www.iso15926.org/part2/2003-12#PhysicalObject > >> is already defined as an OWL class, since your original message spoke of > >> rdf:typing the instances with the applicable OWL classes. That being > >> the case, if you define the instance as an instance of that OWL class, > >> the OWL semantics specify that it's also an instance of owl:Thing, > >> without you having to explicitly say so. Thus as I see it the issue > >> isn't about whether or not you want to be rigorous in distinguishing > >> instances from classes (doing so is always a good idea), it's about > >> whether or not you want to take advantage of built-in OWL semantics to > >> simplify the syntax you write. > >> > >> However, as I said above, I may be missing something, and it won't hurt > >> to write owl:Thing explicitly if you want. > >> > >> > >>>We have to work with IDs like PHO-387392 anyway, since we deal with more > >>>than 20,000 classes and hundreds of thousands of individuals (all the > >>>things that make up an entire oil refinery, and the components thereof, > >>>and the process streams). We had a discussion about naming, and rejected > >>>human-understandable names. What would be the human-understandable name > >>>for a Ford Focus with a wide (not yet made) selection of engines, > >>>colors, accessories, etc? And what if that selection has been made? > >>> > >> > >> No problem. Lots of things are identified (for given applications) by > >> non-human understandable names (very few people refer to me in > >> conversation by my drivers license number, although the Registry of > >> Motor Vehicles insists that I have one anyway). > >> > >> Cheers. > >> --Frank > >> > >> > >>>Regards, > >>>Hans > >> > >> > >> > > > >-- > > > >Ivan Herman > >W3C Communications Team, Head of Offices > >C/o W3C Benelux Office at CWI, Kruislaan 413 > >1098SJ Amsterdam, The Netherlands > >tel: +31-20-5924163; mobile: +31-641044153; > >URL: http://www.w3.org/People/Ivan/ > >
Received on Sunday, 30 October 2005 11:46:37 UTC