Hi Dan:
I think Alan already gave examples this morning. An ontology can contain
statements about the relationship between conceptual elements - classes,
properties, individuals - that (1) influence the result to queries but
(2) are not likely retrieved when you just dereference an element from
that ontology. The more complex an ontology is, the more difficult is it
to properly modularize it.
But basically my main point is that the use of owl:imports is defined
pretty well in
http://www.w3.org/TR/owl-ref/#imports-def
and there is no need to deviate from the spec just for the matter of gut
feeling and annoyance about the past dominance of DL research in the
field. And as the spec says - with a proper owl:imports statement, any
application can decide if and what part of the imported ontologies are
being included to the local model for the task at hand.
Martin
Dan Brickley wrote:
On 22/6/09 23:16, Martin Hepp (UniBW) wrote:
Yves Raimond wrote:
Ontology modularization is
a pretty difficult task, and people use various heuristics for
deciding what
to put in the subset being served for an element. There is no
guarantee that
the fragment you get contains everything that you need.
There is no safe way of importing only parts of an ontology, unless you
know that its modularization is 100% reliable.
Serving fragments of likely relevant parts of an ontology for reducing
the network overhead is not the same as proper modularization of the
ontology.
Can you give a concrete example of the danger described here? ie. the
pair of a complete ("safe") ontology file and a non-safe subset, and
an explanation of the problems caused.
I can understand "there is no guarantee that the fragment you get
contains everything you need", and I also remind everyone that
dereferencing is a privilege not a right: sometimes the network won't
give you what you want, when you want it. But I've yet to hear of
anyone who has suffered due to term-oriented ontology fragment
downloads. I guess medical ontologies would be the natural place for
horror stories?
cheers,
Dan
--
--------------------------------------------------------------
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen
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Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!
========================================================================
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http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009
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