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[closed] Re: OWL Questions!

From: Jim Hendler <hendler@cs.umd.edu>
Date: Wed, 2 Apr 2003 13:31:15 -0500
Message-Id: <p05200f21bab0d9566c83@[10.0.1.4]>
To: "Davide Noaro" <noarodavide@libero.it>
Cc: public-webont-comments@w3.org

Hi,
I'm an italian student of computer science and I'm interesting in Web 
Ontology Language.
I read documents about it, but i didn't understand well how OWL works 
and the relation with RDFS.... here some questions

1) OWL is an extension of RDFS? That is, OWL has much expressive 
power than RDFS ( i can express thing that with RDFS i coudn't ) or 
it's equal but it can express relation and properties more easily?

2)There are some pratical example of the use and usefulness of OWL? ( 
Not test cases of W3C or Wine ontology)
    I think to a tool that can do something usefull with an ontology....

I think that without some very pratical example people cound't 
understand well how ontology work and why develop them. Thanks for 
any answer... and sorry for my english! ;-)
Davide.

-----------------------------------------------------------
Davide Noaro
<mailto:noarodavide@libero.it>noarodavide@libero.it
------------------------------------------------------------

David-
  There are many places to learn more about OWL and the projects 
relating to it and to DAML+OIL (its predecessor).  A good starting 
place for answering your questions are in the OWL Overview [1] and 
Guide [2] and in the Web Ontology Language Use Cases document [3], 
all of which have recently moved to Last Call status (meaning we are 
soliciting comments)
  Let me give you brief and informal replies to the questions you ask 
above.  If you want more information, an excellent place to ask 
questions is on the mailing list www-rdf-logic@w3.org which 
encourages such discussion.

1 - OWL is an extension of RDF(S) -- that is, all RDF and RDFS 
documents are legal OWL Full documents and all OWL documents are 
legal RDFS documents.  However, OWL extends the vocabulary of RDFS to 
allow some more expressivity.  For example, in OWL you can say that a 
property is required (owl:minCardinality of 1) or optional 
(owl:minCardinality of 0) and other such things.
   That said, OWL does have some special subsets that are identified 
in our documents (OWL Lite, OWL DL and OWL Full) - two of which have 
some special restrictions, but some nice properties for reasoning 
systems. Not all RDFS documents are necesssarily in OWL Lite or OWL 
Full.  Details can be foudn in our documents.

2 - There have been many practical applications of DAML+OIL, the 
predecessor langauge to OWL, those can be found discussed on the 
(non-W3C) DAML web site [4].  The Web Ontology Working Group home 
page [5] contains some pointers to OWL tools and we will be adding 
pointers to OWL ontologies and demos over the next few weeks or 
months.  Stay tuned.


[1] http://www.w3.org/TR/owl-features/
[2] http://www.w3.org/TR/owl-guide/
[3] http://www.w3.org/TR/webont-req/
[4] http://www.daml.org/
[5] http://www.w3.org/2001/sw/WebOnt/



-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-731-3822 (Cell)
http://www.cs.umd.edu/users/hendler
Received on Wednesday, 2 April 2003 13:31:23 GMT

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