Re: Fwd: Linked data and rdf:type in dbpedia

Tim,
Suppose it will be good to use "class of classes" and many very good
foundations from the EPISTLE Core Model -
http://www.tc184-sc4.org/wg3ndocs/wg3n1328/lifecycle_integration_schema.html
(see the list of Entities on the left).

Leonid Ototsky - http://ototsky.mgn.ru/it

Âû ïèñàëè 20 ìàÿ 2007 ã., 23:07:50:



> Begin forwarded message:

> From: Tim Berners-Lee <timbl@w3.org>
> Date: 2007-05-19 19:27:56 EDT
> To: Chris Bizer <chris@bizer.de>
> Cc: tabultor@csai.mit.edu
> Subject: Linked data and rdf:type in dbpedia


>  Hi Chris.


> That was a great session in Banff. 


> I'm looking now at a problem where the Tabulator sucks in huge
> amounts of dbpedia.  The problem is rather random rdf:type links


> 1. My home page says:


> <http://dbpedia.org/resource/Tim_Berners-Lee> = card:i.


> 2. That causes tab'r to bring
> in http://dbpedia.org/resource/Tim_Berners-Lee
> which in turn says


>    <http://dbpedia.org/resource/Tim_Berners-Lee>    
> a   <http://dbpedia.org/resource/Category:People_from_London>.


> 3. That causes Tab'r to look up the
> class Category:People_from_London


> $ cwm http://dbpedia.org/resource/Category:People_from_London


> This says a bunch of people  whose have subject of that
>    <http://dbpedia.org/resource/Catherine_of_York>     :subject <> .
> which is fine, but it also says:


>    <>     a </class/yago/person>,
>                
> <http://dbpedia.org/resource/Category:English_people_by_county>,
>                 <http://dbpedia.org/resource/Category:London>,
> <http://dbpedia.org/resource/Category:People_by_city_or_town_in_England>,
>                 :Concept.


>   Here I think the use of rdf:type is incorrect.   The class
> People_form_London is a class of people.  It is a subclass of Person.


>   It has no simple relationship to London. (It is in fact an
> owl:Restriction on property origin to value london, but I doubt if
> you can generalize that across dbpedia).


>   English people by County  *could* be a class of classes.




> The tabulator assumes that every time it follows rdf:type it is
> going meta: from classes to classes of classes, etc.  It does this
> as in every other case so far, there have been only a few levels
> (like 2).


> Currently, it can't use dbpedia as it pulls it memory-busting
> amounts of it.  It not even clear that the rdf:type links don't have
> cycles.


> Anyone using OWL with this data wil of course find t impossible
> to deal with classes of classes at all.  I don't know to what extent
> the issue is an 




> Example:


> me : Unitarian
> http://en.wikipedia.org/wiki/Tim_Berners-Lee


>     is a member of the class of


> http://en.wikipedia.org/wiki/Category:Unitarian_Universalists


>     this is a member of the metaclass:


> http://en.wikipedia.org/wiki/Category:People_by_religion


>     this i member of the metametametaclass of ways in whcih people are categorized


> http://en.wikipedia.org/wiki/Category:People


>    What follows here is the weak link.  Reference is a section of the library.
>     "This category is for information typically found in the
> reference section of a library: reference works."  Now the meta meta
> class  is regarded as a work? o-oh.


> http://en.wikipedia.org/wiki/Category:Reference


>    it continues, following Category (rdf:type in dbpedia):


> http://en.wikipedia.org/wiki/Category:Knowledge
> http://en.wikipedia.org/wiki/Category:Information
> http://en.wikipedia.org/wiki/Category:Physical_quantity
> http://en.wikipedia.org/wiki/Category:Measurement
> http://en.wikipedia.org/wiki/Category:Scientific_observation
> http://en.wikipedia.org/wiki/Category:Data_collection
> http://en.wikipedia.org/wiki/Category:Data_management
> http://en.wikipedia.org/wiki/Category:Product_development
> http://en.wikipedia.org/wiki/Category:Product_management
> http://en.wikipedia.org/wiki/Category:Engineering
> http://en.wikipedia.org/wiki/Category:Applied_sciences
> http://en.wikipedia.org/wiki/Category:Science
> http://en.wikipedia.org/wiki/Category:Knowledge


> Ooops! It is cyclic.


> The logical relationships are not consistent.  i don't know
> whether there are a finite number of 
> categories for which rdfs:class does not work, which could be put
> into a stop list.  "Reference" would be one.


> I wonder whether dbpedia could either find a way of judging which
> ones are really rdf:type relationships, or just use something vaguer
> for the relationship.
> Maybe wikepedia:category would be best as that is what it is in general.


> Tim















-- 
Ñ óâàæåíèåì,
 Leonid                          mailto:leo@mgn.ru

Received on Sunday, 20 May 2007 19:16:14 UTC