- From: Hans Teijgeler <hans.teijgeler@quicknet.nl>
- Date: Sun, 30 Oct 2005 09:57:02 +0100
- To: "'Ivan Herman'" <ivan@w3.org>
- Cc: "Manola, Frank" <fmanola@acm.org>, <semantic-web@w3.org>, "Paap, Onno" <onno.paap@ezzysurf.com>
- Message-Id: <200510300857.j9U8v6hA006179@vmx80.multikabel.net>
Hi Ivan,
Would this be acceptable:
<owl:Thing rdf:ID="PHO-387392">
<rdf:type
rdf:resource="http://www.iso15926.org/part2/2003-12#PhysicalObject"/>
</owl:Thing>
?
Regards,
Hans
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"/>
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 08:57:41 UTC