> I'd like to propose, if it is feasible, a way forward on the issue
> of creating an SV. Namely that:
>
> 1. subject to discussion and resolution of the points raised in
> Andrea's Note, sections 3.1/2/3, we proceed with the creation of a
> SV by a subgroup of this wg;
> 2. that the SV should be created in the OWL format, for which
> there are several tools, not least, Protege;
> 3. that all initial relationships between SV terms be members of
> either the NarrowerThan or BroaderThan classes (with the inverse
> relationship being a member of the other);
> 4. every release of the OWL format be accompanied by a translation
> into the SKOS format for use as a W3C standard vocabulary (other
> formats for individuals or subgroups to create from either of these
> releases).
> 5. the subgroup produces a first draft within one month of the
> interop using the terms already defined in Andrea's Note so that
> the wg can check it out and finally sign off that this is a viable
> way forward;
> 6. during that same month, the wg discuss and agree on the issues
> in points 3.1/2/3 and any others in the Note;
> 7. when the first draft is agreed, the SV subgroup continue its
> work, producing further drafts no slower than one per month;
> 8. using these drafts, people who wish to work with vocabularies
> produce test applications for discussion here and presentation at
> the next interop (using the SKOS or other derived formats);
> 9. using these drafts, people who wish to work with ontologies,
> extend the SV ontology as necessary and produce applications that
> demonstrate the use and usefulness of ontologies to astronomy, also
> for presentation at the next interop;
> 10. and that following these presentations at the next interop,
> the wg decide whether to continue with a separate SV development or
> to accept that all applications can be met with an ontology or some
> other outcome.
> The above would ensure that the SV could be created as quickly as
> some people seem to think is necessary using a well-known and
> popular tool (Protege). This initial effort would have as its scope
> only the terms useful in an SV (need to define what this is). The
> relationship between terms would be limited to a small number of
> relationship types, all of which must be classifiable (in
> vocabulary terms) as narrower or broader. This latter will ensure
> that a classic SKOS-type (and any other type) of vocabulary could
> be derived from the ontology and that it will conform to the multi-
> hierarchy form explained by Bernard.
Bravo, Tony, a good start. However.....
The understandable restriction to use only NarrowThan and BroaderThan (the maximum amount of ontological info that could/should be kept within what is just supposed to be a "vocabulary"), I'd say that we should use SKOS for starts, which has practically no unnecessary ontological baggage used or implied (!) and - as far as I can see (but I'd be happy to be corrected) - will be more compact: assuming we'll want 1) the token itself (only for computers), 2) a human- readable equivalent, 3) any aliases, 4) any NarrowerThan's and BroaderThan's, e.g.
<skos:Concept rdf:about="BARRED_SPIRAL_GALAXIES"> <skos:prefLabel>barred spiral galaxies</skos:prefLabel> <skos:altLabel>SB</skos:altLabel> <dc:description>Spiral galaxies having a radial bar-like structure in their spiral pattern.</dc:description> <skos:broader rdf:resource="#SPIRAL_GALAXIES"/> </skos:Concept>
That's it (well, add more altLabel's, broader's and narrowers, and maybe dc: documentation about changes, but otherwise....). This is exactly what SKOS is intended to do, so unless someone can show that OWL is shorter/simpler..... Even if SKOS is changed, we're just talking about the minimum info
token=BARRED_SPIRAL_GALAXIES label=barred spiral galaxies alt=SB description=Spiral galaxies having .... bt=SPIRAL_GALAXIES
which we could publish as a text file. Correspondingly, the OWL is trivially produced from either format if you're interested (some of us are definitely NOT).
Secondly, I suggest we use the IAU thesaurus as a starting point : sure, it has lots of historical baggage and a heavy old-fashioned stellar emphasis, but the VO may want to keep the possibility of referring to old photoelectric photometry or scanned photographic plates etc. since it doesn't cost anything and the thesaurus has the _very_substantial_ political advantage of being already officially accepted - we want to make this process as short and painless as possible! The problem with the IAU thesaurus was that it was just a long list with no obvious use: the VO and the HTN provide the framework for being able to use it. We can look at the differences between the IAU thesaurus and the proposed SV to see what needs to be updated (a process I've already started). As a by-product, we get an automatic version in French, German, Spanish, and Italian - a good example of a secondary vocabulary document which can be published and immediatelly used by, e.g., the AOIM people or HTN projects which have to interact with the public. The corresponding conversion documents for AOIM, A&A, HOU, ADS, SIMBAD,.... would follow easily, so that we could start with a reasonable sample of useful vocabularies which approaching the IVOA for final acceptance.
By keeping the vocabularies just vocabularies, the ontological work thereafter can be thought of as a further process by which the multiple vocabularies are studied in their native habitats, from which further ontological connections can be gleaned. If you just need tokens, you just throw away a few lines of XML or use the NT's and BT's to help track down potentially useful alternative tokens and you're finished; if you want ontologies, the conversion to OWL is equally trivial and you can start building upon the vocabulary as much as you want. Nobody can really complain. We'd be welcome to publish official version as HTML (handy for determining what tokens are already there, especially if a few search tools are provided), SKOS (minimum defining XML version), and a derived OWL document for those who are interested.
I'm at a conference this week but will post my first cut of an improved IAU thesaurus for discussion next week.
Rick
Dr. Frederic V. Hessman Hessman-at-Astro.physik.Uni-Goettingen.DE Institut für Astrophysik Tel. +49-551-39-5052 Friedrich-Hund-Platz 1 Fax +49-551-39-5043 37077 Goettingen Room F04-133http://www.Astro.physik.Uni-Goettingen.de/~hessman
http://monet.Uni-Goettingen.de ------------------------------------------------------------------------ -------------------------Received on 2007-09-24Z13:39:24