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Re: What is needed to move forward

From: Pierre-Antoine Champin <pchampin@liris.cnrs.fr>
Date: Mon, 09 Feb 2009 10:15:34 +0000
Message-ID: <49900246.5080805@liris.cnrs.fr>
To: fsasaki@w3.org
CC: public-media-annotation@w3.org


disclaimer: I was not at the F2F meeting (shame on me), so I may have a
wrong interpretation of the requirement for "slices of conformance",
which has been discussed there.

It seems to me that we are discussing on the ground of a
misunderstanding, that might be crystalized in the stating of req-r11
[1]. There are two sides in using RDF (or any other ontology language,
for that matter): formalization and serialization, or "what is
expressed" vs. "how it is expressed".

It seems to me (I may be wrong), that you are focusing on the
serialization issue: in your mails and in [1], you are often putting
"RDF" and "serialization" together, and opposing it to "prose", which
relates to how things are expressed. From that point of view, I think I
agree with you: we do not want to force all implementations to be able to
parse or serialize (any syntax of) RDF. The first levels of conformance
should be serialization-agnostic.

When arguing in favor of RDF, I am focusing on formalization. I admit
I'm making here a shortcut that may not be trivial, and foster
misunderstanding: RDF in itself has a very basic semantics and does not
provide much tools for formalization. However, RDF opens the door to more
tools: RDFS, SKOS, OWL... Those tools are great, I think, to provide an
(almost) unambiguous definition of the concepts and properties of our
ontology. The fact that they can be expressed in RDF is not important
here (since we are primarily addressing implementors, not machines). So
I like:
  "publicationDate is a sub-property (as in RDFS) of generalDate"
just as much as:
  mawg:publicationDate rdfs:subPropertyOf mawg:generalDate .

But I do think that, without such a formal framework for defining our
we will fail to "help developers with the lack of syntactic and semantic
interoperability" (from the charter).


[1] http://www.w3.org/TR/2009/WD-media-annot-reqs-20090119/#req-r11

Felix Sasaki wrote:
> Hello all,
> there may be the impression that I do not want a semantic web based
> approach for our ontology. This is not the case, and I very much hope that
> one slice of requirement 11
> http://www.w3.org/TR/2009/WD-media-annot-reqs-20090119/#req-r11
> will be an RDF-based ontology. However, I am very worried with approving
> such an approach *at the moment* for various reasons:
> 1) We have in my view an unclear requirement "allow for several
> abstraction layers like FRBR", without a clear scope description and a
> clear relation to existing formats (see separate thread)
> 2) we have no restriction of the expressive power of an implementation.
> Without such a restriction I am worried about feature creep and as a
> result too much complexity in the ontology.
> 3) Of coures 1) and 2) are chicken-and-egg problems: How to decide about
> them if we don't have proposals on the table? We are missing just these:
> small, but concrete proposals for the "semantic web" conformance slice.
> For the conformance slice "prose" we have
> - the table
> - as a proposal how to relate that to the API the draft at
> http://dev.w3.org/2008/video/mediaann/mediaont-api-1.0/mediaont-api-1.0.html
> (think that each row of the table becomase a subsection 4.2.x)
> - an implementation which makes use of such a proposal, and solves the
> granularity problem Joakim mentioned, see the "dateGeneral vs. pubdate"
> example at
> http://lists.w3.org/Archives/Public/public-media-annotation/2009Jan/0027.html
> It would be great to
> - Understand what (if any) problems see people with the "prose" proposal
> as it is described above, and
> - Have somebody creating even a toy implementatin of the ontology and the
> API, the ontology replying to 1), 2) and 3) above. I know about the action
> item for Pierre-Antoine and the SKOS example from Veronique, but I would
> like to see an integrated example, as we have it for the "prose" approach
> already, to know if people only think about SKOS or OWL (which part?), if
> SKOS when which part etc.
> Felix
Received on Monday, 9 February 2009 10:16:18 UTC

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