Andrea Preite Martinez
andrea.preitemartinez at rm.iasf.cnr.it
Thu Jun 2 06:24:38 PDT 2005
I think it is time to remind you what the goal of the Sci-Board on a short
we (eg: IVOA project and people) urgently need a stabilized version of the
Adds-on are possible in this phase, but in the short term (<1 month) the
main job is to get a basic ?kernel? of ?stable? words that can be
immediately used by data providers. The starting point is the list of words
already available as an IVOA-WD.
If the present version of the list is too much ?table/catalogue?-like
for somebody's tastes, I remind that at CDS (just to quote one of the data
centers) about 150.000 columns wait for a ?stable? ucd-vocabulary in
order to be treated (e.g.: to have an ucd assigned to them), their number
growing at the rate of 1000 per month.
What I mean is: they are already there. This is why at the joint UCD-VOEvent
session we decided to postpone the discussion on <UCDs and the VOEvent
vocabulary> (to be precise, on the <hypothesis> schema only, because actual
UCDs are usable in other Event contexts/schemas) : to gather a real working
vocabulary on events and associated hypothesis.
The situation is not very simple : on one hand we have now a <standard> way
(a <precise> way) to define <fuzzy>-enough UCDs, on the other hand we need
to have within the IVOA community (DM, Theory, VOEvent, ..) the
possibility to express the same concepts using the same words. And, why
not, using the same syntax already used for the UCDs.
A way out is to be rigorous and <open> at the same time.
I remind you that in the actual version of UCDs we do have <objects>: in the
sense that we do (we can) distinguish between the temperature of a star (its
effective temperature) and that of a detector or instrument. We do
distinguish between the name/identifier of an astronomical object and that
of a telescope, instrument, or even a fov. In all these cases we use
ucd-words describing <objects> as <qualifiers>.
While today an UCD like : src.galaxies.S0 would be meaningless,
meta.id;src.galaxies.S0 would not. In the UCD context src.galaxies.S0 is
only a secondary word, but in another context it could be used as primary.
We can (I would say: we have to) work in this direction.
I totally agree with Rick's final statement on ontologies: we need standards
NOW, not in 30-40 man-years time!
Andrea Preite Martinez andrea at rm.iasf.cnr.it
Istituto di Astrofisica Spaziale Tel.:+39.06.4993.4641
Area di Ricerca di Tor Vergata Fax.:+39.06.2066.0188
Via del Fosso del Cavaliere 100 Cell:+39.339.3817355
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