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Re: Press.net News Ontology

From: Bob Ferris <zazi@smiy.org>
Date: Fri, 09 Sep 2011 14:59:20 +0200
Message-ID: <4E6A0DA8.3030507@smiy.org>
To: semantic-web@w3.org
Hi Paul,

thanks a lot for your reply.

On 9/9/2011 11:20 AM, Paul Wilton wrote:
> Hi Bob
> In most of these cases you have pointed out, we have inherited from
> the classes/properties

Even inheriting a term should be done carefully, i.e., it should 
especially come along with a concrete plausible definition which differs 
from that of the inherited term. Reasoning is still an expensive task 
today. Try to express as much knowledge in a direct way.

> you mention for very good practical reasons,
> either as we want to specialise further the class in question (eg
> sub_event on the public domain event ontology was not transitive, so
> we have defined our own specialized property that is transitive).

Well, regarding the concrete example you've mentioned, you could propose 
this change also to the authors of the Event Ontology (especially, since 
the project source was recently moved to GitHub [1], you could init a 
Pull Request; that's a way how modern ontology could be done in a 
shared, collaborative environment).

> The other very practical reason is that we *want* to define a ontology
> for news with its own classes and predicates.

Yes, this always looks to me like database schema or MDA modelling.

> We have subclassed
> public domain ontologies where we feel the public domain ontology is
> widely used, so that when RDF is published we wil also be publishing
> the ancestor classes and properties for consumers that understand it.

So you'll materialize all the way down?

> This also addresses the practical architectural problem of contract
> binding. Developers of APIs built around this ontology can bind  to
> the press.net classes and properties, decoupling themselves from
> public domain ontologies which our out of their control.

They can bind the press.net terms as easily as terms of other namespaces 
(I'm waiting for the muddy counter argument: "don't confuse us with to 
much namespaces"). Furthermore, the press.net ontologies are looking to 
me like public domain ontologies (of the news domain) as well more or less.

> As these
> (public domain) ontologies evolve the press.net ontology can be
> modified accordingly with respect to the public domain ontologies
> while not breaking the contracts of those clients bound to the
> press.net ontology.  This is good practice in my opinion.

This looks like a redundant cycle to me.

> We are considering dropping the skos inheritance altogether, as skos
> is particularly cumbersome around inverseOf properties and their own
> ancestors resulting in n*n*8 statement chains being inferred from a
> n-depth classification scheme - (using pns:subClassificationOf
> subPropertyOf skos:narrower)

Please show me the added value of the majority of the term definitions 
of the press.net ontology.



[1] https://github.com/moustaki/motools/tree/master/event
Received on Friday, 9 September 2011 13:00:08 UTC

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