Beyond the draft proposal

[Alasdair Gray]

Brian Thomas wrote:
> Hi Norman, all,
>
> On Monday 04 February 2008 4:48:58 pm Norman Gray wrote:
>   
>> Brian and all, hello.
>>
>> On 2008 Feb 4, at 18:01, Brian Thomas wrote:
>>
>>     
>>> On Monday 04 February 2008 10:55:04 am Frederic Hessman wrote:
>>>       
[snip]
>> Remember that we're defining _vocabularies_ here.  One of the main  
>> distinctions between vocabularies and ontologies is that the former  
>> service a different goal from the latter.  That goal is searching, or  
>> something very like it; vocabularies are much closer to humans -- to  
>> UIs -- than ontologies are, and in consequence they are inevitably  
>> messier.
>>     
>
> 	I'm aware they are different, however, I don't like messy things,
> 	and its not clear to me that a vocabulary is purely for human-machine
> 	interaction, as seems to be implied above. Perhaps it is, but I still
> 	don't understand why that makes the vocabulary necessiarily messy. 
> 	Having a controlled, clean set of unique tokens, seems to me a very good
> 	thing. 
If the compound terms are going to be in common usage by the astronomers 
who will ultimately be using the ivoa software that makes use of the 
vocabularies then they need to be first class citizens in the vocabulary 
and not derived from some grammar for combining terms.
> Do we really have to canvas every possible meaning, and way of
> 	expressing that meaning, into the vocabulary? Some terms seem to be
> 	of very limited utility. I point to the earlier example  of having "volcano" 
> 	included as a token/term.
>   
It depends on how wide you want the coverage of your vocabulary to be. 
If the idea of the IVOAT is to cover all terms then yes, they all need 
to be in there. This does not preclude the setting up of smaller, more 
focused vocabularies with clearly defined mappings to the IVOAT.
> 	As for the messiness, well, its a natural impulse for me to want to see 
> 	the plural terms (floating in a sea of singular tokens), the repetition of 
> 	meaning between more than one token, the degeneracy in meaning of 
> 	a token removed or cleared up. 
>
> 	As for compound terms, I didn't say we should have none of those, but perhaps 
> 	the IVOAT is just a bit overboard in this area. Witness the already large 
> 	size of the thing. Cutting some of these out will surely remove "bloat".
>   
In terms of vocabularies, the IVOAT and IAUT are both on the very small 
end with only about 2-3,000 concepts. It is not uncommon for 
vocabularies to contain 60-70,000 concepts.
> 	
[snip]
>  
>   
>> And I think the result _should_ look much like the IAU original.  My  
>> impression of what was being aimed at in the IVOAT was a tidied up and  
>> updated IAU93.  Let's keep it simple and quick.
>>     
>
> 	Yes, well, we are beyond simple and quick now. To my mind that would
> 	have encompassed no more than technical editing (just enough to get 
> 	the IVOAT into SKOS). But we have added terms and have (at last count)
> 	4 vocabularies in total (are all of those going into the draft??). So its a 
> 	matter of opinion that the process has been sufficiently limited.
>   
The skos version of the IAUT should not alter its content at all. 
However, the IVOAT should contain the concepts that are in use now.
>   
>> [snip]
>>
>> As a separate thing:
>>
>>     
>>> And I would also like to add that I'd like to see a *dictionary* of  
>>> the vocabulary
>>> terms. This then would settle the semantic meaning of these tokens,  
>>> which is
>>> the crutial missing link between a vocabulary to ontology usage. I  
>>> have been
>>> rebuffed/ignored about adding the definitions to the SKOS vocabulary
>>>       
>> Have you?  Gracious, no: I think it's important to have scope-notes in  
>> the vocabulary where possible.  The only problem here is that the  
>> definitions in the IAU93 (coming back to that) are rather terse, and  
>> in many cases are just the IAU93 term translated to lowercase.  In  
>> that case, however, an elaborate scope note may not be vital, because  
>> most of those terms are immediately intelligible to the intended  
>> community (ie, astronomers) to the degree of precision appropriate to  
>> a vocabulary (as opposed to the degree necessary for an ontology).
>>     
>
> Soo.. you are in favor of including something beyond repeating the token
> name under skos:description? 
>   
I would say that the IAUT, A&A keywords and AOIM vocabularies will 
unfortunately not contain very good definitions as the original source 
vocabularies are lacking in this area. However, the IVOAT *should*, 
actually *must*, contain definitions of all of the concepts, otherwise 
the whole exercise is wasted as no-one will know the true meaning of the 
concepts. Whether taking these from on-line dictionaries is the best 
approach is open for debate.

Cheers,

Alasdair
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