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Re: relation between ontology

From: <ewallace@cme.nist.gov>
Date: Thu, 4 Dec 2003 15:29:20 -0500 (EST)
Message-Id: <200312042029.PAA21908@clue.msid.cme.nist.gov>
To: www-rdf-logic@w3.org, yongchun.gao@mail.mcgill.ca


"Yongchun Gao" <ygao25@po-box.mcgill.ca> wrote:

>Can OWL "unite" all the ontologies? Or OWL is just a way to represent 
>ontology on the Web?

OWL is an ontology language for the web that can also represent a 
number of sorts of relationships between elements of different ontologies.

>
>In OWL, there are subClassOf, subPropertyOf, etc. From first sight, it 
>seems that OWL can unite at least some ontology. But giving an simple 
>example.

subClassOf and subPropertyOf are part of the RDFS vocabulary.  OWL 
extends this with additional ways to link elements of different ontologies.
These include equivalentClass, equivalentProperty, sameAs, and boolean 
combinations of class expressions.


>Suppose someone developed an ontology by OWL, in which "humans" is a class 
>and has "hasGender" as a property (value=male/female). A man could be an 
>instance of "humans" which "hasGender" of "male". It can work well.
>
>Suppose anther expert developed an ontology by OWL too, in which "humans" 
>and "animals" are classes, but "females" and "males" are classes too (can 
>be attached to both "animals" and "humans"), and "men" is just two subclass 
>of both "humans" and "males". It may work too.
>
>But the problem here is HOW to unite these two different OWL files which 
>tell the same ontology?

These are not the same ontology.  They are different ontologies that take
slightly different approaches to modeling overlapping domains.  One way
to "merge" these using OWL would be to use much the same approach as
suggested by Drew McDermott.  Create a new OWL document where you define 
different namespaces for each of the other ontology's vocabularies, import 
the ontologies, and add axioms such as:

  <owl:Class rdf:ID="&T1:Human">
    <owl:equivalentClass rdf:resource="&T2:Human">
  </owl:Class>

  <owl:Class rdf:ID="&T1:Man">
    <owl:equivalentClass rdf:resource="&T2:Man">
  </owl:Class>

Where the T1 ontology already contains definitions such as:

  <owl:Class rdf:ID="Gender"/>
      <owl:oneOf rdf:parseType="Collection">
          <owl:Item rdf:resource="#Male" />
          <owl:Item rdf:resource="#Female" />
      </owl:oneOf>
  </owl:Class>

  <Gender rdf:ID="Male"/>
  <Gender rdf:ID="Female"/>

  <owl:Class rdf:ID="Man"/>
    <subClassOf rdf:resource="Human">
      <owl:Restriction>
	<owl:onProperty rdf:resource="#hasGender"/>
	<owl:hasValue rdf:resource="#Male"/>
      </owl:Restriction>
    </subClassOf>
  </owl:Class>

and T2 has definitions such as:

  <owl:Class rdf:ID="Human"/>
  <owl:Class rdf:ID="Male"/>

  <owl:Class rdf:ID="Man">
    <owl:intersectionOf rdf:parseType="Collection">
      <owl:Class rdf:about="Human"/>
      <owl:Class rdf:about="Male"/>
    </owl:intersectionOf>
  </owl:Class>

-Evan

Evan K. Wallace
Manufacturing Systems Integration Division
NIST
ewallace@nist.gov
Received on Thursday, 4 December 2003 15:29:22 GMT

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