Re: Vocabulary re-use

DB: "This means that, in general, semantic web developers must learn to deal with ontological mismatches."
The statement is confounding and self-contradictory. As such, it is not "semantic web", but rather "meaningless web", where we have most succeeded :-). 
Azamat Abdoullaev
http://standardontology.org
 


  ----- Original Message ----- 
  From: Martin Hepp (UniBW) 
  To: David Booth 
  Cc: Aaron Rubinstein ; semantic-web@w3c.org 
  Sent: Wednesday, September 30, 2009 12:34 PM
  Subject: Re: Vocabulary re-use


  Hi David:

  Excellent points. One thing we should observe, though, is that there is a strong lever if you design your initial patterns carefully and reuse existing ontologies. It is a bit more effort for the publisher, but it saves a lot of effort for the world (and thus increases the likelihood that your data will be used/considered).

  Also note that the level of detail and the precision of conceptual choices in the ontology you use finally limits the quality of any later mapping. If your proprietary ontology mixes apples and oranges (e.g. events vs. tickets for events, users vs. user roles, book titles vs. book copies, etc.), then it is impossible to use that data in contexts that require the distinction. Often, it is easy to make that distinction at the origin, because you still have a lot of contextual information. But once you don't have it in your published data, it is gone. Forever....

  So as a general guideline, additional human intelligence when choosing the patterns for exposing your data pays out.

  Martin


  David Booth wrote: 
Aaron Rubinstein wrote:
    [ . . . ]
  The other part of my question is: does it matter?  Can the Semantic 
Web support a plethora of similar but distinct vocabularies as long as 
applications are 'smart' enough to interpret the ontology and make 
inferences accordingly?
      
The semantic web has no choice, because there *will* be a plethora of
similar but distinct vocabularies.  As Martin Hepp pointed out, this
will happen because it is easier for the publishers of those
vocabularies, even though it makes more work for the consumers.
Furthermore, different applications have different needs: some will need
finer distinctions than others.  These finer distinctions may be
essential to some applications, but they just add complexity to
applications that don't need them.  This means that, in general,
semantic web developers must learn to deal with ontological mismatches.

  These questions arise, to a certain extent, out of what seems like a 
prevalent practice to convert existing encoding standards from certain 
domains that are described using XML Schemas into RDF using RDFS and 
OWL, without much awareness of existing ontologies that might suit the 
needs of the domain just as well.  In a nutshell, is this OK or is it 
bad for the Semantic Web?
      
If those XML schemas already exist then this sounds like a good first
step to me.  HOWEVER, the initial ontology you get from converting the
XML schema is not likely to be the one you want to use, as it is likely
to reflect too many artifacts of your XML schema.  In my opinion, that
ontology -- which I would call the "native ontology" -- should only be
used to bridge between the XML and the domain ontology that you really
want to use, which should be designed according to the needs of your
domain.  Rules can then transform from the native ontology to the domain
ontology, so that XML instance data can be automatically transformed
into the desired RDF (expressed in the domain ontology).  The benefit of
this approach over using XSLT to transform directly from XML to RDF is
that the transformations can be defined at a more semantic level, so one
is a bit more insulated from the idiosyncrasies of XML.

Incidentally, this is one way that Gloze
http://jena.hpl.hp.com/juc2006/proceedings/battle/paper.pdf 
is used.  Gloze, given an XML Schema, will automatically transform XML
instance data to RDF.  It can also transform from RDF to XML instance
data -- potentially using a *different* XML schema.  Gloze is part of
the jena suite of RDF tools.

On the other hand, if you are already an XSLT wizard anyway, there's
nothing wrong with transforming directly from XML to RDF expressed in
your desired domain model.

  

-- 
--------------------------------------------------------------
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

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