VOEvent v2.0, some thoughts

[Frederic Hessman]

Whoops - just getting too enthusiastic there and temporarily  
forgetting the difference between tokens and labels - sorry!.

Rick

On 22 Jan 2008, at 1:55 pm, Alasdair J G Gray wrote:

>
>
> Frederic V. Hessman wrote:
>>
>> On 21 Jan 2008, at 8:52 pm, Roy Williams wrote:
>>
>>>>     2) support for IVO vocabularies (for <Why> and <What>)
>>>
>>> How can I say "supernova Ia" using one of the vocabularies?
>>
>> How about any of the following, to be found in already existing  
>> SKOS vocabulary files:
>>
>>     iau93:SUPERNOVAES                        (1993 IAU thesaurus -  
>> available now)
>>     aoim:StarEvolutionaryStageSupernova            (AOIM working  
>> group thesaurus - available now)
>>     ivoat:typeIaSupernova                        (proposed IVOA  
>> thesaurus - available now)
>>     ivoat:snIa                                    (Ibid., just an  
>> alternate label - available now)
> Of course, you wouldn't be tagging the resource with the  
> alternative label, that should only be used to help humans to find  
> the URI for the vocabulary term.
>
> Alasdair
>>
>>  or
>>
>>     voe:supernovaIa                                (if Roy wants a  
>> native VOEvent token - TBD)
>>
>> For example:
>>
>>     iau93 : http://www.astro.physik.uni-goettingen.de/~hessman/rdf/ 
>> IAU93/IAU93.rdf
>>     ivoat:  http://www.astro.physik.uni-goettingen.de/~hessman/rdf/ 
>> IVOAT/IVOAT.rdf
>>
>> and official copies will be available soon at a central IVOA URI  
>> as soon as the official draft of semantics working group is  
>> submitted.
>>
>> Note that a human-readable short descriptive text (e.g. "Supernova  
>> of type Ia") is available for all of these tokens, so one can  
>> already use these terms in a real-live GUI.
>>
>>> Do I have to import a schema?
>>
>> No, SKOS/XML is basically pretty simple XML and you're welcome to  
>> parse the even simpler N3- or Turtle-formatted equivalent  
>> representations.
>>
>> However, if you want to be exact, you'll need, e.g.
>>
>>     <!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#">
>>     <!ENTITY rdfs "http://www.w3.org/2000/01/rdf-schema#">
>>     <!ENTITY dc "http://purl.org/dc/elements/1.1/">
>>     <!ENTITY dct "http://purl.org/dc/terms/">
>>     <!ENTITY skos "http://www.w3.org/2004/02/skos/core#">
>>
>> (the "dc" things are Dublic blah-blah-blah doc stuff, if you also  
>> want to parse various other doc information).
>>
>>> What would the <Why> section look like?
>>> In the <What> section, we are having trouble with those  
>>> parameters which are links to further information. We are mashing  
>>> up VOEvent feeds for Google Sky (voeventnet.org), and each  
>>> placemark on the sky may have links to finding chart, event  
>>> portfolio, photometry file, etc, which should be linked from that  
>>> placemark. But each event stream uses different types of Params  
>>> or References for these.
>>
>> Good question.   Given that we are pushing the current limits of  
>> standard semantic-web technology (lots of ideas out there, but few  
>> standards), I'm afraid that there aren't too many tools for  
>> actually USING the vocabularies in the sense of being able to say  
>> "the event is either an X or a Y plus Z but definitely not a W" in  
>> a standard syntax, much less Roy's ultimate test case, "the  
>> eclipse occured when a G3V star went in front of the K3 giant".
>>
>> Within the current VOEvent <param> paradigm, we could easily and  
>> quickly use something like (I'm brainstorming here for didactic  
>> purposes only...)
>>
>>     <group name="object">
>>         <param name="object-type" rdf:resource="iau93:SUPERNOVAS"/>
>>         ...
>>     </group>
>>     <group name="telescope" rdf:resource="ivoat:telescope">
>>         <param name="focal-length"  
>> rdf:resource="ucd:instr.tel.focallength" value="8770"  
>> units="millimeters"/>
>>         ...
>>     </group>
>>     ...
>>
>> The use of rdf:resource attributes makes the contents semantic-web- 
>> compatible, since each of the entries can be identified by someone  
>> with little knowledge of what the document actually means or is  
>> intended with a global vocabulary, so that the contents of  
>> different documents can be compared/linked just on this basis.   
>> Note that I slipped in a reference to UCD expressed in terms of  
>> RDF.  Note also that one can mix-and-match, according to your  
>> needs, i.e. no more monolithic "UCD and that's it".
>>
>> If the VOEvent working group can figure out what terms are
>>     1) needed, and
>>     2) not yet present in an existant vocabulary,
>> then we can produce a special VOEvent vocabulary with nearly zero  
>> effort (after the terms have been identified).
>>
>> Try http://www.astro.physik.uni-goettingen.de/~hessman/rdf/
>>
>> Rick
>>
>
> -- 
> Dr Alasdair J G Gray
> http://www.dcs.gla.ac.uk/~agray/
>
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