On 1/2/12 2:13 AM, Patrick Cassidy wrote:
---------------------
On 12/31/11 5:34 PM, Patrick Cassidy wrote:
[pc] Kingsley,
Thanks for pointing out that example of use of the ontology.
This may be a good example to discuss the effects of changing to
"type" relation to "subclass" as it is used for the biological
taxonomy. The type relation appears to be used in the same sense that
the rdf:subclasOf is used in other OWL ontologies. In the usual
usage, if X has type Y, then X is an individual in the class Y, not a
subclass. But in the ontology and its associated applications, to
determine the parent classes (at some levels) one apparently needs to
use the "type" rather than subclass relation (i.e. "Albatross" is
usually a subclass, not an instance of "Bird"). It also appears that
the subclass relation is not propagated up the hierarchy, as it should
be for a transitive relation.
[KH] Transitivity kicks in when you enable inference context. This is
simply off by default. There are a number of ontologies that also
serve as inference rules. Enable those, and you will see what you
expect. The cost of these operations is why we turn them off by default.
----------------
Is this inference enabled in the extraction from infoboxes to the
DBpedia triple store?
No.
Or is there a way to enable transitiity during the SPARQL query
process?
Yes, via SPARQL pragma.
You can also enable inference context when using the faceted brower we
provide.
The other issue is why, in relating the WikiPedia pages to the
ontology, "type" is used to relate, e.g.
"http://dbpedia.org/page/Albatross"; to "Bird", rather than
"subcassOf". The heading of that page has:
About: Albatross <http://dbpedia.org/resource/Albatross>
An Entity of Type : eukaryote <http://dbpedia.org/ontology/Eukaryote>,
from Named Graph : http://dbpedia.org, within Data Space : dbpedia.org
<http://dbpedia.org>
It is this usage of "Type" that I find problematic. Is there a reason
for this -- is it not intended to mean the same thing as rdf:type?
Yes, it means rdf:type.
Didn't want to print:
An Entity of rdf:type: ....
Of course, if people find that clearer, we can change in nano seconds :-)
It appears at first glance as if this were adopted as a means to keep
the ontology small (so Albatross does not have to be added as a class
to the ontology) -- is that part of the motivation?
No, just trying to find a very simple way to get people to understand
what a Linked Data descriptor document from DBpedia is trying to convey.
Kingsley
Pat
Patrick Cassidy
MICRA Inc.
cass...@micra.com
908-561-3416
*From:*Kingsley Idehen [mailto:kide...@openlinksw.com]
--
Regards,
Kingsley Idehen
Founder& CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca handle: @kidehen
Google+ Profile: https://plus.google.com/112399767740508618350/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen
------------------------------------------------------------------------------
Write once. Port to many.
Get the SDK and tools to simplify cross-platform app development. Create
new or port existing apps to sell to consumers worldwide. Explore the
Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
http://p.sf.net/sfu/intel-appdev
_______________________________________________
Dbpedia-discussion mailing list
Dbpedia-discussion@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion
