Re: VOConcepts paper

From: Doug Tody <dtody-at-nrao.edu>
Date: Thu, 1 Dec 2005 13:37:16 -0700 (MST)


Right! This is the classical problem of explicit hierarchy versus flat or mostly-flat namespaces which are associated in a more general fashion (e.g., hierarchical versus relational structures). Unless you are trying to model a single complex entity it is almost always better to use the relational approach where simple, well-defined entites are associated. This allows more complex relationships to be described, permits multiple views of the same data, and in some cases can permit inference. The namespace/mapping approach is a good one for vocabularies. For structured data one does much the same thing, but the namespace in this case is a component data model. - Doug

On Thu, 1 Dec 2005, Rob Seaman wrote:
> If UCDs were used to create and track such lists, one could attempt to
> achieve the same many-to-one mapping by relying on the hierarchical nature of
> UCDs: filter.R.this_is_a_specific_wideband_R_filter. This has problems on
> both ends. First, there will often be a redundant prefix like "filter." and
> second, who is to say that it is the "R-ness" of the filter that we wish to
> capture in a short nickname? Perhaps we rather need to capture the
> "wideband-ness" of the filter. The problem with relying on a hierarchy in a
> single namespace is precisely that only one hierarchy exists per namespace.
> On the other hand, multiple mappings are trivial with multiple namespaces.
Received on 2005-12-01Z20:37:50