UType proposals

[Mireille Louys]

Dear all,

I have been following the various points on the Utype discussion thread 
on the various lists.
I thank you for your various contributions and ideas , that offers other 
aspects than the one discussed in the draft I circulated just when the 
IVOA meeting started in Strasbourg.

I just want to remind you that we would like to agree on a simple Utype 
representation from the data model point of view, well focused on 
implementations at the application level as well as the protocol level.
Our first focus is to discover, access and manipulate data of various 
archives.
This is why we need to stick on the object programming properties 
underlying the data modeling effort and the Utype string definition.

Considering the corpus of Utypes within a specific data model, like 
SimDB, Observation, Characterisation, Simple spectral Line , etc...
one touches other vocabulary considerations. These are outside the scope 
of the data modeling group, at least for the moment.

What I find interesting in Norman's proposal is the possibility to 
enhance the documentation aspect of data models, which is tricky to 
manage properly.
I think we can have a compromise in the Utype string definition, so that 
the uri mecanism would allow to define the name space and build up links 
to proper documentation pages describing classes of the model and their 
attributes in well defined structured document.

Remember that a Utype string is derived from a data model, its root name 
always derives from a class name, identifying a concept in the model so 
the critiscism that it is a simple string unaware of his context is not 
valid.

The documentation can be organised so that a Utype string like :
obs:Curation.PublisherId is interpreted on the fly :
a) resolve the name space  obs --> http://ivoa.net/DM/Observationv0.9/
b) build up a link to the proper documentation page
http://ivoa.net/DM/Observationv0.9/Documentation/Curation.html
c) open it and highlight the 
http://ivoa.net/DM/Observationv0.9/Documentation/Curation.html 
#Curation.PublisherId section within this page.

This is not as sophisticated as an ontology , but it would certainly 
help data providers and users to implement, and use models.

cheers, mireille




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  Mireille LOUYS          mailto: Mireille.Louys at astro.u-strasbg.fr

L S I I T                       &     CDS,
Ecole Nationale Superieure            Observatoire de Strasbourg
de Physique de Strasbourg,            11, Rue de l'Universite
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