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Re: my token about the "3 or more layer" structure for the ontology

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Thu, 20 Nov 2008 08:10:19 +1100
Message-ID: <2c0e02830811191310v52cd02abr404bcb93880b20f0@mail.gmail.com>
To: "Ruben Tous (UPC)" <rtous@ac.upc.edu>
Cc: public-media-annotation@w3.org

Hi Ruben,

It is always a matter of use cases.

When we talk about management of collections, there will be overlap
between the annotations of different files, which can be handled more
efficiently (in a database sense: normalise your schema).

However, if you receive an individual media resource, you want all of
its annotations to be available with the media resource, i.e. you want
an "intelligent" media object that can tell you things about itself.

I don't see these things as separate. Let's take a real-world example.
Let's assume I have a Web server with thousands of videos. They fall
into categories and within categories into event, where each video
within an event has the same metadata about the event. On the server,
I would store the metadata in a database. I would do normalisation of
the data and just store the data for each event once, but have a
relationship table for video-event-relationships. Now, a Web Browser
requests one of the videos for playback (or a search engine comes
along and asks about the metadata for a video). Of course, I go ahead
and extract all related metadata about that video from the database
and send it with the video (or in the case of the search engine:
without the video). I further have two ways of sending the metadata: I
can send it in a text file (which is probably all the search engine
needs), or I can send it multiplexed into the video file, e.g. as a
metadata header (e.g. MP3 has ID3 for this, Ogg has vorbiscomment,
other file formats have different metadata headers).

I don't think we need to overly concern ourselves with whether we
normalise our data structure. This is an "implementation" issue. We
should understand the general way in which metadata is being handled
as in the example above and not create schemas that won't work in this
and other scenarios. But we should focus on identifying which
information is important to keep about a video or audio file.

Cheers,
Silvia.



On Thu, Nov 20, 2008 at 12:01 AM, Ruben Tous (UPC) <rtous@ac.upc.edu> wrote:
>
> Dear Véronique, Silvia, all,
>
> I agree with both of you in that the need of multiple description levels is
> only related to a small subset of use cases, basically to those related to
> the management of groups of resources (e.g. digital asset management
> systems, user media collections, etc.). Instead, we are (I guess) focused in
> embedded annotations in individual resources.
>
> However, I think that there are solutions which cover both cases, the simple
> and the complex one. For instance, we could embed the following annotation
> within an MPEG video:
>
> <mawg:Video rdf:ID=http://example.org/video/01">
> <mawg:title>astronaut loses tool bag during spacewalk </mawg:title>
> <mawg:creator>John Smith</mawg:creator>
> </mawg:Video>
>
> <mawg:Resource rdf:ID="http://example.org/resource/01">
> <mawg:format>FLV</mawg:format>
> <mawg:filesize>21342342</mawg:filesize>
> <mawg:duration>PT1004199059S</mawg:duration>
> </ mawg:videoID rdf:resource="http://example.org/video/01">
> </mawg:Resource>
>
> It is structured and it offers 2 abstraction levels, but it can be
> serialized like a plain record. When appearing in isolated resources, the
> high-level annotation ("Video" in this case) would be repeated. When
> appearing within a collection's annotation the "Video" annotation would
> appear just once.
>
> It is not so different than in XMP. Take to the following XMP example...
>
> http://www.w3.org/2008/WebVideo/Annotations/wiki/images/8/8a/Xmp_example.xml
>
> Best regards,
>
> Ruben
>
>
> ----- Original Message ----- From: <vmalaise@few.vu.nl>
> To: <public-media-annotation@w3.org>
> Sent: Wednesday, November 19, 2008 11:27 AM
> Subject: my token about the "3 or more layer" structure for the ontology
>
>
>>
>> Hi everyone,
>>
>>
>> I was at first very much in favor of an ontology that would distinguish
>> different levels of media documents, like
>> "work-manifestation-instance-item",
>> but after reading this email from the list:
>>
>> http://lists.w3.org/Archives/Public/public-media-annotation/2008Nov/0076.html
>> I agreed with the fact that we would probably only need a simple structure
>> in
>> our case, that multi-level structures were meant for linking different
>> entities
>> that have different status together: if we aim for linking the
>> descriptions of a
>> single item between different vocabularies, we need to specify if the
>> single
>> item is a work_in_XX_vocabulary, more likely a
>> manifestation_in_XX_vocabulary
>> (see note 1 below), to give its "type", and if people/use cases want to
>> link
>> this single item to other related works, manifestations, instances or
>> items,
>> they can use the framework defined in the schemas reviewed in
>>
>> http://www.w3.org/2008/WebVideo/Annotations/wiki/MultilevelDescriptionReview
>> and use these properties for completing their description.
>>
>> So we would need a property like "has_type" to link a single description's
>> identifier to the correct level of multilevel description schemes.
>>
>> I changed my mind think that only one "family" of use cases would need
>> more
>> levels, that they are somehow context dependent (and could thus be
>> considered as
>> requirements for a family of use cases), but of course if it turns out
>> that more
>> that one family of use cases needs this distinction, then we should
>> consider
>> going for a multilevel structure. Anyway, we would need to map informally
>> the
>> way these levels are expressed, in order to provide possible relevant
>> "types"
>> for the description of each single element.
>>
>> note 1: by specifying the different names of the relevant Concepts/terms
>> in
>> schemes like VRA, XMP etc., we would informally define a semantic
>> equivalence
>> between the ways these schema express these levels of description. It
>> would look
>> like:
>> <metadataFile>
>> <id="identifier">
>> <hasType xmpMM:InstanceID, vra:image, frbr:item>
>> </metadataFile>
>>
>> I think that the table
>> http://www.w3.org/2008/WebVideo/Annotations/wiki/FeaturesTable
>> is a very valuable tool for people to express their ideas about it, thank
>> you
>> very much Ruben for designing it!
>>
>> Best regards,
>> Véronique
>>
>>
>>
>
>
>
Received on Wednesday, 19 November 2008 21:11:00 GMT

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