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In SimDB, particularly in its data model, we aim to use pre-defined semantic vocabularies. The idea is that certain "label" attributes in the model should obtain their values form such a vocabulary, to indicate in an agreed upon vocabulary what the meaning is of a certain object. Examples are the "ucd" attribute on InputParameter, or the "label" attribute on TargetObject

Some feedback on this idea was provided by Norman Gary (TBD find email link).

To discuss:

• How about our formalisation of the usages of semantc vocabularies in UML (stereotype + tag definition (for URI)). (also to DM)
• How about our idea to restrict values to those in the vocabulary, or should we merely "suggest" its usage?
• Which vocabularies are appropriate to the particular labels, or do we need to create new ones?
• Currently in profile the stereotype is named <>, though a word in a SKOS vocabulary is intended. Should we rename, or should we keep this name for possible future generalisation?
• If we stick to SKOS, how should the values actually be provided. As preferedLabel, as URI, as ???
• Should we support, in the TAP query interface, querying for narrower/broader terms as well? (Could be done by introducing a database model for the vocabularies and their relations ...)
• ...
• Should we create an RDF representation of the data model. In particular if Norman's proposal for UTYPEs¹ is followed a UTYPE must be resolvable to an "RDF expression of its semantics".

¹ See http://www.ivoa.net/Documents/Notes/UTypes/utype-uri-20070302.html

1. Regard the datamodel_identifier prefix above as an XML namespace, with the syntactic requirements that implies, and interpret the UType as a URI naming a concept.
2. Require that each UType URI be resolvable, on the web, to human-readable documentation for the concept thus named.
3. Require that each UType URI be resolvable, separately, to a formal (RDF) expression of its semantics, which would therefore be immediately retrievable, aggressively cacheable, and easily used by software to interpret data annotated with the UType.

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