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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