v0.8.3 posted; supporting tables

[Ray Plante]

Hello Resource Metadaters,

Thanks to everyone for their comments on VOResource 0.8.2.  Sorry I
haven't been able to follow up on all the comments individually--I
have tried to digest them all, though.  I've posted updated versions
of the schema on the twiki, along with links to XMLSpy documentation
and a new overview document: 

http://www.ivoa.net/internal/IVOA/IVOARegWp03/VOResource-v0.8.3-overview.html.

There is still work going on, so keep your comments coming.  In
particular, work is still underway integrating the space-time
coordinate metadata.  Other topics are still under discussion.  

XMLSpy documentation and an updated version of the example,
adil-v0.8.3.xml, for these new versions can be found at 
http://nvo.ncsa.uiuc.edu/~rplante/VO/schemas/VOResource-v0.8.3-pre/

One major item bit of feedback (e.g. from Roy, Anita, etc.) is that
the v0.8.2-based schemas do not provide a way to describe tables
sufficiently to enable discovery at the registry level.  While
critically important, we hadn't gotten down to this level of detail in
the structure, yet.  

The newly posted schemas illustrate one way to handle this.  SIA-v0.5.xsd
and ConeSearch-v0.1.xsd provide the metadata to describe the tables
returned by these services.  

Another way to do this (which is not implemented here) is to describe
tables as a kind of DataCollection independent of any service that
accesses it.  This would involve defining a new Resource class, Table,
to add the necessary metadata.  Personally, I think this is a bit too
fine-grained for registering data; however, AstroGrid may prefer to do
it this way.  If so, I would encourage the project to persue the
design of the Table resource class.

Another way to support tables is to incorporate the table metadata
(e.g. UCDs) directly into the core VOResource metadata.  Because we
can identify currently defined Resource classes where UCDs do not
apply (e.g. Organisation, DataCollections representing an image
archive), I would not recommend this approach.  

cheers, and thanks again for the careful examinations!
Ray