Re: DBpedia 3.2 release, including DBpedia Ontology and RDF links to Freebase

John,

Here's an observation from a bystander ...

On 17 Nov 2008, at 17:17, John Goodwin wrote:
<snip>
> This is also a good example of where (IMHO) the domain was perhaps  
> over specified. For example all sorts of things could have  
> publishers, and not the ones listed here. I worry that if you reuse  
> DBpedia "publisher" elsewhere you could get some undesired inferences.

But are the DBpedia classes *intended* for re-use elsewhere? Or do  
they simply express restrictions that apply *within DBpedia*?

I think that in general it is useful to distinguish between two  
different kinds of ontologies:

a) Ontologies that express restrictions that are present in a certain  
dataset. They simply express what's there in the data. In this sense,  
they are like database schemas: If “Publisher” has a range of  
“Person”, then it means that the publisher *in this particular  
dataset* is always a person. That's not an assertion about the world,  
it's an assertion about the dataset. These ontologies are usually not  
very re-usable.

b) Ontologies that are intended as a “lingua franca” for data exchange  
between different applications. They are designed for broad re-use,  
and thus usually do not add many restrictions. In this sense, they are  
more like controlled vocabularies of terms. Dublin Core is probably  
the prototypical example, and FOAF is another good one. They usually  
don't allow as many interesting inferences.

I think that these two kinds of ontologies have very different  
requirements. Ontologies that are designed for one of these roles are  
quite useless if used for the other job. Ontologies that have not been  
designed for either of these two roles usually fail at both.

Returning to DBpedia, my impression is that the DBpedia ontology is  
intended mostly for the first role. Maybe it should be understood more  
as a schema for the DBpedia dataset, and not so much as a re-usable  
set of terms for use outside of the Wikipedia context. (I might be  
wrong, I was not involved in its creation.)

Richard

Received on Monday, 17 November 2008 20:09:47 UTC