Re: [semanticweb] Ontology of interests

Am 26.07.2006 um 10:35 schrieb Hamish Harvey:

> On 25/07/06, Knud Hinnerk Möller <knud.moeller@deri.org> wrote:
>
>> * in the foaf:interest example the wikipedia URL obviously  
>> identifies the
>> page, as Damian pointed out, but then you'd still need to say what  
>> the
>> foaf:topic of the page is, because if we have
>>    * Danny foaf:interest
>> <http://en.wikipedia.org/wiki/Resource_Description_Framework>
>> .    and
>>    * Knud foaf:interest <http://www.w3.org/RDF/> .
>
> Presumably you can strongly encourage people (e.g. in the FOAF docs; I
> haven't looked) to prefer pages from e.g. Wikipedia over some
> arbitrary even if apparently canonical page. If the page isn't there,
> add it.

Yes, you could, and such a convention would be nice. However, it will  
be hard to get everyone to follow it. Again, the heart of the problem  
I mentioned (the "URI crisis") is that a lot of things can get messed  
up if people use the URLs of physical things on the internet (e.g. a  
web page) to _also_ denote an abstract concept that this URL is  
somehow related to. If you only have one homogeneous source of data  
or community, an informal convention like the one you suggest might  
be enough. However, if you imagine an agent traversing the whole wide  
SW, collecting and integrating data from all kinds of sources (and  
that's what would be so cool about the SW), then a solution like that  
could easily break. As said before, this problem does not arise in  
the foaf:interest example, due to the way this predicate is defined  
(i.e. the object _is_ a foaf:Document).

>> * then how could anyone (without a human brain) know that we are both
>> interested in RDF? This could only be inferred if we also say:
>>    *
>> <http://en.wikipedia.org/wiki/Resource_Description_Framework>
>> foaf:topic <nice.uri.for.RDF> .    and
>>    * <http://www.w3.org/RDF/> foaf:topic <nice.uri.for.RDF> .
>
> Besides, what's wrong with saying, without using another URI:
>
> <http://en.wikipedia.org/wiki/Resource_Description_Framework>  
> foaf:topic _:rdf .
> <http://www.w3.org/RDF/> foaf:topic _:rdf .
>
> ?

Using a blank node only works if these two statements were made in  
the same model. If they come from different places, you need an  
explicit URI.


> Another concern is the drift in meaning of assertions you'll get using
> something like Wikipedia to provide a "controlled" vocabulary. When I
> assert
>
> _:me foaf:interest <http://en.wikipedia.org/wiki/...> .
>
> I really mean I have an interest which is described by that page at
> the time the assertion was made.
>
> Probably not such an issue in geek space with well defined  
> technologies.

No, I think that is indeed an issue - the well defined technologies  
do not define very well what using a URL like <http:// 
en.wikipedia.org/wiki/Resource_Description_Framework>  actually means!

Cheers,
Knud

-------------------------------------------------
Knud Möller, MA
+353 - 91 - 495086
Digital Enterprise Research Institute
   National University of Ireland, Galway
Institiúid Taighde na Fiontraíochta Digití
   Ollscoil na hÉireann, Gaillimh