Re: [OPEN] and/or [PORT] : a practical question

I may be misunderstanding your question, but I believe it is quite simple: 
if you want to treat classes as instances you are in OWL Full.  There is 
simply no way to do that in DL or Lite, this was one of the basic 
differentiators between the subsets and the full language.

-Chris

Dr. Christopher A. Welty, Knowledge Structures Group
IBM Watson Research Center, 19 Skyline Dr., Hawthorne, NY  10532     USA   
 
Voice: +1 914.784.7055,  IBM T/L: 863.7055, Fax: +1 914.784.7455
Email: welty@watson.ibm.com, Web: 
http://www.research.ibm.com/people/w/welty/



"Bernard Vatant" <bernard.vatant@mondeca.com> 
Sent by: public-swbp-wg-request@w3.org
03/19/2004 05:02 PM

To
"SWBPD" <public-swbp-wg@w3.org>
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Subject
[OPEN] and/or [PORT] : a practical question








This is a practical question that we have often met in Mondeca. The 
message below comes
from a partner in an European project, developing linguistic tools to 
generate queries on
a semantic knowledge base.

To sum up the issue, the question is how to express that the subject 
(dc:subject) of a
document is a concept used as a class in an ontology, e.g "Phd_Theses". My 
view is that if
you don't want to be in OWL-Full, the only way is to make distinct the 
concept used as
class and the concept used as document subject (defined as instance in a 
thesaurus).
The argument against that is that the search engine could leverage the 
ontology
subsumptions to expand queries e.g. from "find documents about 
publications" to "find
documents about PhD Theses" ... more arguments below in Patrizia Paggio 
message.

Best practice for that, folks ?

Bernard Vatant
Senior Consultant
Knowledge Engineering
Mondeca - www.mondeca.com
bernard.vatant@mondeca.com

-----Message d'origine-----
De : Patrizia Paggio [mailto:patrizia@cst.dk]
Envoye : vendredi 19 mars 2004 11:28
A : Bernard Vatant
Cc : Lina Henriksen; CST
Objet : Re: Federated questions


Dear Bernard
since you ask directly for my opinion, here it comes :-) .

I think I'm sceptical about the so-called thesaurus solution probably 
because I don't
totally understand why it is smart (alas, in spite of all these email 
exchanges!).
Let me try and explain the way I see things without getting into details 
with OWL -Full.
To take the Webpage on PhD theses, I think we wish to be able to express 
the fact that the
Webpage is also about dissertations, and about publications in general, as 
predicted by
the isa structure: Publication <= Dissertation <= PhD Thesis. This means 
in my opinion
that if the user asks for a Webpage on Publications, the page on PhD 
Theses should be
among the hits. In general, I think it is fair to say that if a document 
is about a
certain university-relevant concept in our ontology, it is also at the 
same time about the
concepts that subsume the concept under consideration.
Now, if this is true, it seems to me that if we cannot (or do not want to) 
allow the
Subject class to subsume classes in the ontology in a direct fashion, well 
then we need to
replicate the whole ontology (that is excluding instances) and call it a 
thesaurus. If
this is smart (and possible) - I suppose that's what we should do.
As far as the linguistic implementation is concerned, it doesn't make any 
sense to me to
have two versions of the ontology, one of which is used to express 
subclasses of the
Subject concept. As a matter of fact, we couln't even do it because of 
name clashes. So we
would ignore the thesaurus if the thesaurus is the same as (or fragments 
of) the ontology.
By the way, what is a good definition of a thesaurus?

________________________________________________________

Patrizia Paggio

Senior Researcher                                phone: +45 3532 9072
Center for Sprogteknologi                fax:   +45 3532 9089
Njalsgade 80                                             email: 
patrizia@cst.dk
2300-DK CPH S www.cst.dk/patrizia

LREC04 Workshop on Multimodal Corpora
http://lubitsch.lili.uni-bielefeld.de/MMCORPORA

LREC04 OntoLex 2004
http://www.loa-cnr.it/ontolex2004.html
________________________________________________________