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Re: http://ld2sd.deri.org/lod-ng-tutorial/

From: Giovanni Tummarello <g.tummarello@gmail.com>
Date: Tue, 23 Jun 2009 08:01:11 +0100
Message-ID: <210271540906230001q2c58d8cemeca5c80b7b763ef7@mail.gmail.com>
To: martin.hepp@ebusiness-unibw.org
Cc: Michael Hausenblas <michael.hausenblas@deri.org>, hepp@ebusiness-unibw.org, Richard Cyganiak <richard@cyganiak.de>, "Hepp, Martin" <mhepp@computer.org>, Hugh Glaser <hg@ecs.soton.ac.uk>, mark.birbeck@webbackplane.com, "Booth, David (HP Software - Boston)" <dbooth@hp.com>, "public-lod@w3.org" <public-lod@w3.org>
Just a remark about what we're doing in Sindice, for all who want to
be indexed properly by us.

we recursively dereference the properties that are used thus trying to
obtain a closure over the description of the properties that are used.
We also consider OWL imports.

When the recursive fetching is computer, we apply RDFS + some owl
reasoning (OWLIM being the final reasoner at the moment) and index it.

We are currently working on a public validator where people can try
their files and see the full chain of fetching/inference.


On Mon, Jun 22, 2009 at 7:42 PM, Martin Hepp
(UniBW)<martin.hepp@ebusiness-unibw.org> 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.
> 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:  mhepp@computer.org
> 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
Received on Tuesday, 23 June 2009 07:02:03 UTC

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