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Re: What is needed to move forward

From: Felix Sasaki <fsasaki@w3.org>
Date: Mon, 09 Feb 2009 19:48:26 +0900
Message-ID: <499009FA.5040802@w3.org>
To: Pierre-Antoine Champin <pchampin@liris.cnrs.fr>
CC: public-media-annotation@w3.org

Hello Pierre-Antoine,

Pierre-Antoine Champin wrote:
> Felix,
>
> 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
> ontology,
> we will fail to "help developers with the lack of syntactic and semantic
> interoperability" (from the charter).
>   

Here I fundamentally disagree. I think that deliverable from the
metadata working grop
http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf
is a great contribution to the syntactic and semantic interoperability
of media objects - without a formal approach. And: it is driven by many
big players in media objects production and consumption - which we
currently have not on board. Using a similar approach like in that
deliverable could help us to get them on board.

And again, I would like to see one simple example how the formalization
is supposed to work - from the table / prose, to the formalization & the
API. Without such an example I have a very hard time to find answers to
questions Jean-Pierre has:

[
- what is the role of structured XML schemas (what do they do that e.g.
RDF/OWL doesn't or maybe less adequately like cardinality and type or ID
management)
- if I go for an RDF/OWL model, what is its role? How different is it from a
dumb RDF description (why is it NOT rdfising existing XML schemas? What
makes its value and who will integrate it to exploit metadata instances
(what would search engines do with it)?
- How do I generate instances? From where (transformation from structured
metadata instances or from a database)? What are the tools to generate valid
templates from complex models?
- etc. Where are tools? Why will/should large communities ignore the RDF/OWL
model and why it makes sense because they don't need it to generate valuable
metadata?
...
]
Which conclude with the statement "Quite a lot of work to be done", for
the formalization. I very much doubt that it is worth the effort, if
nobody comes up with a simple example to demonstrate its value.

I would rather like to spend time on what Jean-Pierre proposed:

"I would therefore suggest that we dedicate part of the next physical
meeting
going through these issues asking everyone of us to come with a
presentation. "

With the modification that I would like to spend this time also during
telephone calls and via mail.

Felix

>   pa
>
> [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 10:49:04 GMT

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