Format of concatenated UCD's

[Rob Seaman]

On Jun 9, 2005, at 5:30 AM, Frederic V. Rick Hessman wrote:

> I'd like to see the use of parsed UCDs alongside what the VOEvent  
> group has been discussing as VOConcept (same syntax as UCDs,  
> different purpose) which would allow elements such as
>
>     <Thing purpose="{list of UCDs and VOConcepts}"/>
> e.g.
>     <Explanation description="event.burst em.opt"/>
>
> (dummy example for an optical burst) where you can see that the  
> combination of standard UCD syntax with VOConcept added is exactly  
> what one needs to extend the present functionality while keeping  
> the same usage.

The last time I raised this issue (http://ivoa.net/forum/ucd/ 
0504/0166.htm), the thread spiraled off into ontologies.  Maybe we  
can try again.  There appears to be a lot of friction resulting from  
some implicit requirement that UCDs and VOConcepts occupy the same  
namespace and be in thrall to the same standards process.  From where  
I'm sitting, however, they appear to simply represent different  
problems with similar solutions.  VOConcepts may want to borrow UCD  
syntax, but they don't have to therefore coexist in the same namespace.

Is there some technical reason that Rick's example can't become  
"con:event.burst ucd:em.opt"?  Let's try to avoid getting lost in the  
semantic underbrush.  Please tell me why we can't have separate  
namespaces?

I've resisted cross-posting.  Please let me know if you believe this  
will be more productively addressed elsewhere.

Rob Seaman
NOAO