Vocabulary: Ontology

[Rob Seaman]

Tony Linde wrote:

> So why don’t we take advantage of all the money they’ve spent on  
> developing standards and tools to work with those standards. It  
> seems a little perverse to say that we have less money so we’ll  
> spend it duplicating what others have already done.

The issue isn't just development cost - it's cost of operations.  A  
case could perhaps be made that using RDF would reduce the total  
lifecycle cost for the VO (centers and/or users).  That case has yet  
to be made.

>  And I’m sure it would not take much hunting to find examples of  
> equally obtuse text from astronomers or even (heaven forfend) astro- 
> developers.

Certainly the latter, but I find the assertion regarding the former  
to be questionable.  Obtuse and complex are not the same thing.   
"Epistemology"?  Perhaps the study of the female parts of flowers?   
No - rather, the "branch of philosophy that investigates the origin,  
nature, methods, and limits of human knowledge".  That is obtuse on  
its face.  On the other hand, astronomy is a branch of physics.  The  
physical answer to the same question is the Uncertainty Principle.   
You can actually calculate observable phenomena (e.g., line  
broadening) using the U.P.

"Because it's there" is a necessary and sufficient reason to include  
domain knowledge (e.g., "black hole") in a vocabulary or ontology.   
"Because it's there" is insufficient cause to choose a particular  
technology.  The case must always be made from the point of view of  
the needs of the domain customer.

Bernard Vatant wrote:

> Go to http://dbpedia.openlinksw.com:8890/sparql
> And copy the following SPARQL query in the query box
>
> PREFIX  category:  <http://dbpedia.org/resource/Category:>
> PREFIX  skos:  <http://www.w3.org/2004/02/skos/core#>
> PREFIX  prop: <http://dbpedia.org/property/>
>
> SELECT    ?x ?p
> WHERE {  ?x  skos:subject category:Delta_Scuti_variables.
>                  ?x  skos:subject category:Bayer_objects.
>                  ?x  prop:parallax ?p.}
>
> I am sure it does not need translation in natural language :-) .
> The query results as of today are as following
>
> x 	p
> http://dbpedia.org/resource/Vega 	129.01
> http://dbpedia.org/resource/Beta_Cassiopeiae 	69.5
> http://dbpedia.org/resource/Delta_Capricorni 	84.58
> http://dbpedia.org/resource/Denebola 	90.16
> http://dbpedia.org/resource/Sigma_Octantis 	12.07
>
>
> Put any of those URI in your browser and see what you get.

Now we're getting somewhere.  (I presume we're not to critique the  
user interface here :-)

> All the point now is : Do you care for IVOA data to be merged/ 
> compared or otherwise linked to such public data? Or not?

I think the answer to this specific question is "not".

Rather, if a case is to be made for this technology it will be based  
on whether non-VO facilities are "to be merged/compared or otherwise  
linked" to IVOA data.  Google sky is the proof of concept.

I was a bit snarky in my previous message.  We have need to turbo- 
charge VOEvent to capture the semantics of exo-VO transient alert  
publishers.  As a result, this is not the first time I've gone  
hunting the frumious ontology.  To date, however, my snarks have all  
turned out to be boojums.

Actually, Lewis Carroll vies with Dr. Seuss as the patron saint of  
ontology:

	Come, listen, my men, while I tell you again
	The five unmistakable marks
	By which you may know, wheresoever you go,
	The warranted genuine Snarks.

versus:

	Did I ever tell you that Mrs. McCave
	Had twenty-three sons, and she named them all Dave?

	Well, she did. And that wasn't a smart thing to do.
	You see, when she wants one, and calls out "Yoo-Hoo!
	Come into the house, Dave!" she doesn't get one.
	All twenty-three Daves of hers come on the run!

Rob Seaman
NOAO