VOEvent v2.0, some thoughts

[Alasdair J G Gray]

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/

Explicator project 
http://explicator.dcs.gla.ac.uk/

Office: F161
Tel: 	+44 141 330 6292

Postal: Computing Science,
	17 Lilybank Gardens,
	University of Glasgow,
	Glasgow,
	G12 8QQ, UK.