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RE: [MMSEM-UC] review of MPEG-7 metadata interoperability use case

From: VassilisTzouvaras <tzouvaras@image.ntua.gr>
Date: Wed, 15 Nov 2006 00:03:25 +0200
Message-Id: <200611142203.kAEM3VqP003459@manolito.image.ece.ntua.gr>
To: "'Suzanne Little'" <Suzanne.Little@isti.cnr.it>, <dasiop@iti.gr>, <michael.hausenblas@joanneum.at>, <public-xg-mmsem@w3.org>

Dear Suzanne,

Welcome in the XG. Your background fits perfectly with the activities of
this XG and is very nice that you will contribute in the deliverable. Your
contribution is already noticeable from the extensive review that you made
in the MPEG-7 interoperability use case and I am sure it will give us a lot
of help. 

Some general info: As you may already have informed, the first deliverable
is on semantic interoperability in multimedia applications and currently we
are in the stage of writing use cases presenting the interoperability issues
and providing possible solutions for them using semantic web technologies.
In this deliverable, apart from the use cases, we will include all related
information to semantic interoperability, such as report on metadata
standards (part of it in the vocabulary link), existing works, solution
mechanisms etc.

Regarding the specific comments, 

> 1. Introduction:
> A minor typographical comment about the first point -- the captions
> underneath the example fragments in the introduction section were a bit
> confusing. Initially I thought they were headings. Perhaps some
> adjustment of the layout could clear that up -- caption inside the
> border, smaller text?

You are right it needs adjustment in the layout of the caption.

> The second point is interesting but I'm not sure if I've understood
> correctly. :-) What I think you're saying is:
> 
> Desired behaviour: The query "Images that depict Zidane" should return
> not only images that are directly described but also images that have
> segments (StillRegion) that are described as depicting Zidane. I assume
> that you want such a query to return the containing images and not the
> segments.

You understood correctly. The example tries to show that you may have an
image annotated (possibly manually) as depicting  zidane and another image
that is annotated (possibly automatically) as one of its segments (still
region) is depicting zidane and in this way, in a possible query, we
retrieve only the first image and not the second one as well.

> Problem: Because MPEG-7 doesn't formally define decomposition
> relationships, you can't write a (single? simple? distributed?) semantic
> query that retrieves images (not segments) in both of these cases.
 
agree


> The overall question is: Does this problem (that MPEG-7 doesn't formally
> define decomposition relationships) restrict the interoperability of
> multimedia descriptions that use MPEG-7? I think you address this
> partially in section 2.1 when you mention that the MPEG-7 ontology and
> the upper ontology provides these relationships and therefore enables
> this type of query. So a related question is: if different MPEG-7 or
> multimedia ontologies record these relationships in different ways
> (e.g., subClass vs. partOf) then does this restrict interoperability?

I believe it does and this is one of the major interoperability issues that
this use case is addressing. The different approaches that have been
proposed in the literature are using different way of translating the MPEG-7
semantics using the OWL/RDF semantics. The result is that applications that
for example have followed the MPEG-7-ABC approach and applications that for
example have followed the Tsinaraki approach are not interoperable.


> 3. Possible Solutions
> 
> I'm interested to see what you propose as solutions particularly for
> your first point. How to map between the chosen syntactic structure and
> the semantics in the ontology is an important question. It's hard to
> comment specifically without more detail. I'm particularly curious about
> the first proposed solution. Do you have some examples? Are you
> referring to Jane's work integrating CIDOC/DC/MPEG7/ABC etc? What kinds
> of relationships other than the equality and subClass/Property provided
> by OWL will be required?

There is a mistake in the first point of the possible solution section. The
correct is semantic mappings and not syntactic mappings. The idea is to
exploit SWRL kind of semantics in order to provide semantic mappings between
the different vocabularies. Although, it does not exist a reasoner for the
full expressivity of SWRL, it exists for a cluster of it, DL-safe rules,
which may be enough. This is an ongoing work in my lab and in the possible
solution section we will provide the basic structure of a possible solution
and not the detailed solution.

It would be very nice if you also want to contribute in the possible
solutions of this usecase since you are much experienced in this area. 


Regards,
Vassilis
Received on Tuesday, 14 November 2006 22:04:50 GMT

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