Re: type of http://dbpedia.org/page/Bachelor_of_Arts

Hi Valentina,

(and CCing the DBpedia discussion list)

this is an effect of the heuristic typing we employ in DBpedia [1]. It 
works correctly in many cases, and sometimes it fails - as for these 
examples (the classic tradeoff between coverage and precision).

To briefly explain how the error comes into existence: we look at the 
distribution of types that occur for the ingoing properties of an 
untyped instance. For dbpedia:Bachelor_of_Arts, there are, among others, 
208 ingoing properties with the predicate dbpedia-owl:almaMater (which 
is already questionable). For that predicate, 87.6% of the objects are 
of type dbpedia-owl:University. So we have a strong pattern, with many 
supporting statements, and we conclude that dbpedia:Bachelor_of_Arts is 
a university. That mechanism, as I said, works reasonable well, but 
sometimes fails at single instances, like this one. For 
dbpedia:Academic_degree, you'll find similar questionable statements 
involving that instace, that mislead the heuristic typing algorithm.

With the 2014 release, we further tried to reduce errors like these by 
filtering common nouns using WordNet before assigning types to 
instances, but both "Academic degree" and "Bachelor of Arts" escaped our 
nets here :-(

The public DBpedia endpoint loads both the infobox based types and the 
heuristic types. If you need a "clean" version, I advise you to set up a 
local endpoint and load only the infobox based types into it.

Best,
Heiko

[1] http://www.heikopaulheim.com/documents/iswc2013.pdf




Am 13.10.2014 02:42, schrieb Valentina Presutti:
> Dear all,
>
> I noticed that dbpedia:Bachelor_of_Arts 
> <http://dbpedia.org/page/Bachelor_of_Arts>, as well as other similar 
> entities (dbpedia:Bachelor_of_Engineering, 
> dbpedia:Bachelor_of_Science, etc.), is typed as dbpedia-owl:University
> I would expect a type like “Academic Degree” but if you look at
> dbpedia:Academic_Degree, its type is again dbpedia-owl:University
>
> however, its definition is (according to dbpedia):
>
> "An academic degree is a college or university diploma, often 
> associated with a title and sometimes associated with an academic 
> position, which is usually awarded in recognition of the recipient 
> having either satisfactorily completed a prescribed course of study or 
> having conducted a scholarly endeavour deemed worthy of his or her 
> admission to the degree. The most common degrees awarded today are 
> associate, bachelor's, master's, and doctoral degrees.”
>
> Showing that there are at least two different meanings associated with 
> the term: college/university and title.
> I thing that different meanings should be separated so as to allow 
> applications to refer to the different entities: a university or a title.
>
> At least for me this causes errors in automatic relation extraction...
>
> Wdyt?
>
> Valentina

-- 
Prof. Dr. Heiko Paulheim
Data and Web Science Group
University of Mannheim
Phone: +49 621 181 2646
B6, 26, Room C1.08
D-68159 Mannheim

Mail: heiko@informatik.uni-mannheim.de
Web: www.heikopaulheim.com