Martin Hepp (UniBW) wrote:
Hi Michael:
(moving this to LOD public as suggested)
General note: I am quite unhappy with a general movement in parts of
the LOD community to clash with the OWL world even when that is
absolutely unnecessary. It is just a bad engineering practice to break
with existing standards unless you can justify the side-effects. And
this stubborn "i don't care what the OWL specs says" pattern is silly,
in particular if the real motivation of many proponents of this
approach is that they don't want or cannot read the OWL specs.
As for owl:imports:
When importing an ontology by owl:imports, you commit to the whole
formal account of that ontology. If you just include an element from
that ontology by using it and hope that dereferencing will get the
relevant formal account in your model, you expose your model to
randomness - you don't know what subset of the formal account you will
get served. 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.
On the other hand - what is your pain with using RDFa in a way so
that the extracted RDF model is equivalent to the model from an
RDF/XML or N3 serialization? Why this absolutely arbitrary "we LOD
guys don't like owl:import ( we don't like OWL anyway, you know?), so
we simply omit it" behavior?
It is just silly to break with established standards just for saving 1
- 2 triples.
All,
There is a simple rule of thumb re. technology that ultimately works
long term (i.e. scales when edge cases surface) and its called:
Deceptively Simple. We have to understand that real tech. that makes any
significant difference over the long term always has a strong
"deceptively simple" component to it e.g., HTTP as a prime example.
"Simply Simple" does not work, it doesn't scale due inherent autism re.
edge cases. Popularity != work if you end up down a technology
cul-de-sac, ultimately!
Note: Web 2.0 is the land of "Simply Simple" and in due cause we will
all see that its sole purpose has been evolving the Web to a point where
the case for Linked Data and the essential vision of the Semantic Web
Project are much easier to comprehend and appreciate.
Personally, I will never understand the anti OWL sentiment that appears
to exist in some LOD quarters; especially as OWL based reasoning
combined with Linked instance Data is where the real magic resides.
Courtesy of the GoodRelations Ontology, we're now able to sharpen the
Linked Data value prop. down to a slogan that reads:
Describe your wants/needs or products/services clearly, then simply
leave the Web to do the REST.
The most significant takeaway from Semtech2009 was the fact that Yahoo!
and Google already grok the implications of the statement above, via the
lenses of RDFa as a mechanism for expressing and exposing GoodRelations
based Linked instance Data.
OWL is important, and lets collectively work to improve its
appreciation. What's good for the ABox is also good for the TBox re. our
collective efforts :-)
Kingsley
Best
Martin
Michael Hausenblas wrote:
Martin,
As an aside: I think I proposed already once to not have this discussion in
a private circle of 'randomly' selected people but rather in the appropriate
lists (rdfa public or public-lod). However, if you prefer to continue here,
we continue here, FWIW.
In my opinion the owl:imports
stems from a time where people confused publishing on the Semantic Web with
firing up Protege and clicking around like wild. So, concluding, for me it
is not obvious to use owl:imports and I don't see *any* benefit from using
it. Not in RDF/XML and also not in RDFa ;)
you know that i sometimes appreciate your opinion ;-),
Yeah, same here :D
... but i think it is
pretty questionable to break with well-defined standards specifications
for just a matter of gut feeling and personal preference.
Ok, let me rephrase this. You, or whoever publishes RDFa can of course do
whatever she likes. Wanna use owl:imports? Fine. Don't wanna use it. Ok!
The point I was trying to make (not very successfully, though): from a
linked data perspective (and basically this is what Richard and I try to
achieve here; offering good practices for linked data *in* RDFa) the usage
of owl:imports is, how to put it, not encouraged.
So far I have not heard any convincing argument from you why one should use
it, but I'm happy and open to learn.
Cheers,
Michael
--
--------------------------------------------------------------
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen
e-mail: [email protected]
phone: +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
http://www.heppnetz.de/ (personal)
skype: mfhepp
twitter: mfhepp
Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!
========================================================================
Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/
Talk at the Semantic Technology Conference 2009:
"Semantic Web-based E-Commerce: The GoodRelations Ontology"
http://tinyurl.com/semtech-hepp
Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/
Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe
Project page and resources for developers:
http://purl.org/goodrelations/
Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey
http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009
--
Regards,
Kingsley Idehen Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO
OpenLink Software Web: http://www.openlinksw.com
