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Re: Using DBpedia resources as skos:Concepts?

From: martin <martin@ics.forth.gr>
Date: Tue, 01 Dec 2009 19:56:28 +0200
Message-ID: <4B1558CC.209@ics.forth.gr>
To: Simon Spero <ses@unc.edu>
CC: public-esw-thes@w3.org, Thomas Baker <thomasbaker49@googlemail.com>, maltese@disi.unitn.it
Dear Simon,

I just received this message:

Maltese Vincenzo (Enzo) wrote:
 > You may want to have a look at this paper:
 > http://eprints.biblio.unitn.it/archive/00001610/01/022.pdf
 > We describe issues about the kind of semantics used in classifications and
 > thesauri.
 > You can use SKOS:Concept for real world particulars.
 > However, in this case you rather mean the "set of documents about the
 > individual".
 > I'm available for clarifications.
 > Bests,
 > Enzo

This is exactly my opinion. I formulated in another way below, referring to subjects.

Simon Spero wrote:
> On Fri, Nov 27, 2009 at 2:27 PM, martin <martin@ics.forth.gr 
> <mailto:martin@ics.forth.gr>> wrote:
>     I believe that we are running into a problem if we interpret
>     SKOS:Concept too widely, and allow persons and other particulars be
>     regarded as SKOS:Concept.
>     SKOS:Concept clearly has been designed initially to cover
>     universals, i.e., concepts in the narrower sense, which have
>     "instances" in the real world. This is why SKOS:Concept has
>     properties broader/narrower:
>     "The word "broader" should read here as "has broader concept"; the
>     subject of a skos:broader statement is the more specific concept
>     involved in the assertion and its object is the more generic one. "
>     This clearly does not apply to persons, events and generally not to
>     all "particulars".
> [...]
>     In library classification, persons, such as Shakespeare, may appear
>     as subjects. At least the library of congress describes clearly such
>     concepts as books talking about "Shakespeare", and not as the person
>     itself. In this case, the concept "books about Shakespeare" clearly
>     qualifies as SKOS:Concept. Narrower concepts may be "books about
>     Shakespeare's comedies" or "Shakespeare biographies". The example
>     demonstrates, that a person as literary subject is distinct from
>     identifying the person.
>     There is no contradiction to classify a URI for "Shakespeare" as
>     both a literary subject(SKOS:Concept) and a real person
>     (foaf:person)). However, that does not make every person a subject,
>     and persons behave like a subject! 
> Martin-
> You may be getting confused by the major changes that were made to SKOS 
> in 2008, which altered the semantics of skos:broader. 
> The initial design of SKOS can be seen at: 
> http://www.w3.org/2001/sw/Europe/reports/thes/1.0/guide/20040504/
> One of the  design requirements for SKOS,  R-CompatibilityWithISO2788,  
> required compatibility with ISO-2788. 
> Since ISO 2788 and its kin provide for the instantive relationship 
> (BTI)  the notion of skos:Concept /cannot/ exclude individuals.

I maintain that BTI makes only sense in subject KOS, as Enzo Maltese also supported.
I don't think I am confused with the semantics of skos:broader, I just cited
what the latest definition I found on the Web says:
       "The word "broader" should read here as "has broader concept"; the
       subject of a skos:broader statement is the more specific concept
       involved in the assertion and its object is the more generic one. "

May be this definition does not sufficiently reflect the change in semantics you refer to.

To give an example of particulars in a real life KOS:
LCSH defines the particular "Great Britain" in the sense of a subject as:

	"Great Britain

	Here are entered works on the United Kingdom of Great Britain and Northern Ireland, which comprises England, Northern Ireland, 			Scotland, 
and Wales, as well as works on the island of Great Britain. Works on the Republic of Ireland and on the island of the 		British Isles called 
Ireland are entered under Ireland. Works on the non-jurisdictional island group comprising the islands of Great 	Britain, Ireland, and 
smaller adjacent islands are entered under British Isles.
	URI: <http://id.loc.gov/authorities/sh85056605#concept>"

They don't say "Great Britain is...", but "Here are entered works". That is my point about subjects.
A temporal gazetteer describing the geopolitical unit United Kingdom over different times will have a very different structure, not fitting 
to a simple "broader/narrower".

Another LCSH example:

	"Shakespeare, William, 1564-1616--Family
	URI: <http://id.loc.gov/authorities/sh85120852#concept>
	Type: Personal Name
	Alternate Labels: Shakespeare, William, 1564-1616--Biography--Ancestry; Shakespeare, William, 1564-1616--Biography--Descendants; 	 
Shakespeare, William, 1564-1616--Biography--Family; Shakespeare, William, 1564-1616--Genealogy

	Shakespeare, William, 1564-1616--Biography--Ancestry Shakespeare, William, 1564-1616--Biography--Descendants Shakespeare, William, 	 
1564-1616--Biography--Family Shakespeare, William, 1564-1616--Genealogy
	Broader Terms:

     		* Shakespeare family"

Again, the heading and its broader term clearly indicates that is refers to classes of works, and not the persons as material beings.

Further, we should be aware that we are in the year 2009, and carry over an understanding
of semantic relationships in ISO2788 from 1987, overdue for revision. If, on one side,
we want to support ontologies to build a semantic Web, and on the otherside blur fundamental
semantic distinctions we run into deep compatibility problems. I am a very strong supporter
of SKOS, because I think it is a good idea to have weaker semantics for terminologies and subject
catalogues, but we must be very careful not to create a bad alternative to RDF-OWL itself, in
particular the instantiation mechanism provided there. A clear line will be very helpful.
> "Subjects" are what "documents" are "about"; if X is "about" Y, Y is a 
> "subject" and X is a "document".  Subjects are inten_t_ional.  They 
> aren't about what things are, they are what things are about. 

To my opinion, the best analysis of what a subject is can be found in:
Welty, Chris and Jessica Jenkins. 1999. An Ontology for Subject. J. Data and Knowledge Engineering. 31(2)155-181. September, 1999. Elsevier.

> An antelope, in a museum is a document about the subject of antelopes.
Absolutely not. An antelope, in a museum, is a specimen and not a document. It can
be a Type specimen, if it is the one by which the species is identified. It is
physically preserved. It has no broader terms. You may not be familiar with museums.
A museum is not a library. It preserves the object, not the document. When computers
were introduced, many museums replaced inventory documents with databases, even PHYSICALLY
destroying the documents, using databases, that have not even an identity as documents.

> An antelope with a tattoo of a frog, in a museum, is an antelope and a 
> document, and is about the subject of antelopes, and about the subject 
> of frogs.  It is not a frogelope. 
No, it is a Man-Made Object.
> Should this antelope escape, it remains an antelope, but is not a 
> document, and is not about anything.
Zoos are not museums. Curious example! Should the specimen be transferred to another
museum, both museums would monitor the path, and not keep the document unaltered.
It is more likely that the document is lost in a museum than the object...
Of course the museum object is not about anything, and an object in a museum is an object,
and not a document. Therefore is has no broader terms, just as people.
You may find more about museum processes in the mda SPECTRUM standard..
> Simon



  Dr. Martin Doerr              |  Vox:+30(2810)391625        |
  Principle Researcher          |  Fax:+30(2810)391638        |
                                |  Email: martin@ics.forth.gr |
                Center for Cultural Informatics               |
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Received on Tuesday, 1 December 2009 17:57:32 UTC

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