- From: Pierre-Antoine Champin <pchampin@liris.cnrs.fr>
- Date: Fri, 21 Nov 2008 11:01:57 +0000
- To: Felix Sasaki <fsasaki@w3.org>
- CC: public-media-annotation@w3.org
Felix, although I participated in putting the debate in terms of "XML vs. RDF", my concern was not about a precise syntax or foramt, and I agree with you that it should not be. However in my view the question is more fundamental. Let me reword it. Designing an ontology involves, IMHO, a trade-off between faithfully representing the domain of interest, and projecting it in a practical data structure. Failthful in our context means: - able to cover a large part of legacy metadata - able to satisfy most of the requirements of our use cases Practical in our context, means that the ontology should be: - easy to use by media publisher - easy to implement in browsers A very easy to use and implement data structure is a list of (attribute,value) pairs -- the so-called "flat" structure. By the way, even easier is a list of simple tags -- which can be tweaked into (attribute,value) pairs anyway, as pointed out by your previous mail about flickr. However, I think that this is too much of a simplification: - it does not satisfy come requirements (like the multi-level or collection) -- though we might decide that those ones are too complex - my intuition is that more structure would make "impedence mismatch" between legacy vocabularies easier to point out and solve pa Felix Sasaki a écrit : > > Ruben Tous (UPC) さんは書きました: >> >> Hi Pierre-Antoine, Silvia, all, >> >> I think that normalisation/denormalisation is related to the more >> general discussion about structured*/flat annotations (handling >> events, agents, etc. as separated structures) . The multi-level >> description discussion is probably a sub-topic within that general >> one, and refers only (as I've understood till now) to splitting >> (normalising) the main structure (the one describing the digital >> object) into several entities but only regarding different abstraction >> levels (e.g. document and instance). >> >> So, probably we should decide first about the structured*/flat >> question. If we choose "flat", then we could maybe discard also the >> multi-level description. >> >> Probably, there's a latent high-level question behind this discussion: >> will the ontology model the way annotations are interchanged, or will >> it model their underlying semantic grounding? >> >> Best regards, >> >> Ruben >> >> *When talking about structured annotations I'm not just referring to >> hierarchycal ones (XML), I refer to annotations with ObjectProperties >> (inlined or linked within the same annotation) (e.g. RDF). > > Reading this discussion and the "features" wiki page, the "data model > rows", I have the impression that there is some tension between using > XML and RDF. I can understand that tension, but I think we should not > spend time on discussing it in this group. Nevertheless, it lets me more > and more think that we should not be format specific in our ontology, > but use just a prose description as the normative outcome, that is in > the "Ontology 1.0" Recommendation. If people want to write non-normative > RDF- and XML-formats, they are free to do so. I think we should focus on > formulating the terminology in the prose in a way that that makes a > formalization in whatever format straightforward. > > Felix > > > >> >> >> ----- Original Message ----- From: "Silvia Pfeiffer" >> <silviapfeiffer1@gmail.com> >> To: "Ruben Tous (UPC)" <rtous@ac.upc.edu> >> Cc: <public-media-annotation@w3.org> >> Sent: Wednesday, November 19, 2008 10:10 PM >> Subject: Re: my token about the "3 or more layer" structure for the >> ontology >> >> >> 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 Friday, 21 November 2008 11:02:42 UTC