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: [email protected]
Web: www.heikopaulheim.com
