What use the AstroOntology

[Tony Linde]

So if we use the working hypothesis that the AstroOntology is fixed and is a
complete description of terms used by astronomers and the relations between
those terms, then what relations do we need for which use cases?

The use case specified in Andreas et al's draft, has the AstroOntology used
to assist users in looking for resources in the registry. These resources
have both fixed keywords and free text used to describe them. The assistance
consists of widening and narrowing the terms used in the registry search. I
would guess that the most important relations in this case are
'is-a-type-of' and 'is-synonymous-with' and perhaps 'is-a-component-of'. The
synonyms are used to include all the variants of the term sought by the user
in the search. The types (and perhaps components) are used to allow the user
to choose to include wider or narrower types of the term in the search.
Prior to any use of the AstroOntology (or after any updates), the reasoner
can be run to ensure that all the permutations are forced out: so if A
is-a-type-of B is-a-type-of C then A is-a-type-of C is added; and if B'
is-synonymous-with B then A is-a-type-of B' and B' is-a-type-of C is added.

The first question I would ask is, what use cases do we want to satisfy with
the other relations: has-morphology, has-emission-in etc?

My second question relates more to some confusion of the AstroOntology
overall. We have a list of astronomical objects (BTW wouldn't it be better
to name the top object AstroObject rather than AstrObject?) and putative
relations between them. BUT we are using this (in the draft use case) to
search a registry of resources, not of objects. The metadata describes the
resource and while such metadata may include the type of object picked out
in a catalogue (eg a catalogue of QSOs or of AGNs) and the AstroOntology
would allow the narrowing or widening of the search on this basis, the fact
that the observations were in the X-ray rather than IR is a fact about the
resource not the objects.

I'm not sure I'm being clear here. Basically, what use is the
'has-emission-in' relation? Are we hoping that if the user asks some app to
look for QSOs for her, the app can not only suggest looking for AGNs (if QSO
is-a-type-of AGN) but can also suggest looking at other resources which have
X-ray observations (if QSO has-emission-in the X-ray spectrum range)? If so,
is this useful to the astronomer or is the identification of the QSO so
context driven that no-one would ever just look in other X-ray observations
for QSOs? (apologies for the astro-drivel!)

T.

> -----Original Message-----
> From: owner-semantics at eso.org 
> [mailto:owner-semantics at eso.org] On Behalf Of Anita M. S. Richards
> Sent: 06 March 2007 07:19
> To: Ashish Mahabal
> Cc: semantics at ivoa.net
> Subject: Re: What use the AstroOntology
> 
> 
> On Mon, 5 Mar 2007, Ashish Mahabal wrote:
> 

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