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<p>Hi again,</p>
<p>On this proposal the discussion alraedy started.</p>
<p>For two reasons :</p>
<p> 1 ) some of this (associated_data) had been proposed in the
previous page semantics DataLink Update page :
<a class="moz-txt-link-freetext" href="https://wiki.ivoa.net/twiki/bin/view/IVOA/UpdateDatalinkTerms">https://wiki.ivoa.net/twiki/bin/view/IVOA/UpdateDatalinkTerms</a></p>
<p> -- <a
href="https://wiki.ivoa.net/twiki/bin/view/IVOA/PatrickDowler"
class="twikiLink">PatrickDowler</a> - 2019-05-08 wrote :<br>
</p>
<p>
If the type of the pointed dataset is expressed this way, this
semantics field will help the client designer to send the link for
the target dataset to an appropriate tool , via samp for instance.
</p>
<p>
All links in <a
href="https://wiki.ivoa.net/twiki/bin/view/IVOA/DataLink"
class="twikiLink">DataLink</a> that are not #this are implicitly
"associated". The proposed structure here seems to be drifting
away from vocabulary into something else. Finally, the idea seems
to sanction using terms from the <a
href="https://wiki.ivoa.net/twiki/bin/view/IVOA/ObsCore"
class="twikiLink">ObsCore</a> standard but not very explicitly
or in any machine-readable way (that could be partially improved
by defining an <a
href="https://wiki.ivoa.net/twiki/bin/view/IVOA/ObsCore"
class="twikiLink">ObsCore</a>/dataproduct_type vocabulary).
There is a lot here that needs discussion. <br>
</p>
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------<br>
-- <a href="https://wiki.ivoa.net/twiki/bin/view/IVOA/AdaNebot"
class="twikiLink">AdaNebot</a> - 2019-10-08 wrote :<br>
<br>
For example 2: GAIA DR2 source : links to associated <a
href="https://wiki.ivoa.net/twiki/bin/view/IVOA/TimeSeries"
class="twikiLink">TimeSeries</a> with semantics field
"associated_data:timeseries" -- I don't think this reflects enough
the type of data, it is timeseries, but of what? photometry
(light-curves), but can also be a time series of spectra or
timeseries of radial velocities in the case of Gaia DR3. This means
that there is a need of specialisation of the term timeseries. Same
case is true for the case of missions providing timeseries of images
<br>
<br>
2 ) some discussion happened on the list last week following ada's
renewal of the proposal. see below<br>
<br>
cheers<br>
François<br>
<br>
Pat 2019-10-11 wrote to Ada:<br>
<blockquote type="cite">
<div class="gmail_default" style="font-size:small">The semantics
column in DataLink is supposed to clarify the relationship of
the linked item with the thing with the specified ID -- so it
doesn't necessarily tell you what the resource *is* but rather
how it is related. There are cases where it looks like
semantics says what something is: preview sounds like it is
saying "this is a preview" but it is really saying "this is a
preview of the #this resource".</div>
<div class="gmail_default" style="font-size:small"><br>
</div>
Currently, only the contentType tells you something about what the
download is and that is admittedly not conveying this kind of
detail. It could, or another (new) column could... we should
discuss a detailed example. </blockquote>
<br>
<br>
<br>
François 2019-10-11 wrote to Ada :<br>
<blockquote type="cite">This makes sense.
<br>
<br>
There was already the project to create a new branch
"associated_data" in semantics
<br>
<br>
Subranches would have been at least the dataproduct types of
Obscore + maybe others
<br>
<br>
associated_data:image, associated_data:TimeSeries
<br>
<br>
we can have a further level in branching
<br>
</blockquote>
<br>
Petr Skoda 2019-10-12 wrote to Ada :<br>
<br>
<blockquote type="cite">I am afraid that with trials to assign some
semantics
<br>
we are re-entering the problem of controlled vacabulary , its
management etc ...
<br>
<br>
<br>
in fact the products that may be wanted by the community need not
be just
<br>
time vs- some variable but also a (quite complex) function of
time
<br>
<br>
this is what we tried to address in our note <a
class="moz-txt-link-freetext"
href="http://www.ivoa.net/documents/Notes/CubeDM/20190318/cubeDM.pdf">http://www.ivoa.net/documents/Notes/CubeDM/20190318/cubeDM.pdf</a>
<br>
<br>
e.g. fig.17 - the LIGO requirements - frequency vs strain
<br>
<br>
or I can imagine in asteroseismology people have power spectrum -
i.e.
<br>
Fourier transform vs frequency ....
<br>
<br>
so the
<br>
<br>
timeseries-X has X from a kind of vocabulary ?
<br>
In fact the visibility in radio is by definiton as well a complex
function of time ....
<br>
<br>
could we somehow use UCD (and add missing ones - e.g. the mirror
strain )?
<br>
<br>
and their combination ?
</blockquote>
<br>
Petr Skoda 2019-10-12 wrote also to Ada :<br>
<br>
<blockquote type="cite"><br>
timeseries of images is in fact what we are presenting in our
model in Fig.~13 - to every point of a light curve is associated
the link to original image (here we were thinking about placing
the provenenace )
<br>
<br>
so the time series of images is just a normal time series (where
another "axis" paralel with e.g. flux is an axis of mappings
(links to images)
<br>
<br>
As I have shown in Sydney 2015, the SPLAT , TOPCAT and ALADIN
understand this well and (Fig.15 in a note) displays the image. We
can even support cutouts ...
</blockquote>
<br>
François 2019-10-12 to Petr<br>
<br>
<blockquote type="cite"><br>
But the point raised by Ada was not to address the case where you
want to modelize this but more simply the case where you want to
attach a timeSeries dataset to a source in a catalog (GAIA use
case)<br>
USING DAtaLInk<br>
<br>
Indeed, this is a vocabulary evolution problem. There is a
proposal to extend DataLink vocabulary (semantics field) see (<a
class="moz-txt-link-freetext"
href="https://wiki.ivoa.net/twiki/bin/view/IVOA/UpdateDatalinkTerms">https://wiki.ivoa.net/twiki/bin/view/IVOA/UpdateDatalinkTerms)</a>
<br>
<br>
<br>
We should extend this a little bit in the direction proposed by
Ada<br>
<br>
Semantics working group will manage the procedure.</blockquote>
Ada 2019-10-12 to all<br>
<blockquote type="cite">
<div class="">Thanks for your comments and responses. </div>
<div class=""><br class="">
</div>
<div class="">Pat, content_type (the first field I looked into)
tells you about the format but not about the actual content. At
least this is what I understood.</div>
<div class="">This is why I point to the ”semantics" field and
adding a vocabulary without having to add an extra column for
that. </div>
<div class=""><br class="">
</div>
<div class="">Francois, Associateddata=timeseries-images,…
something like that could work. </div>
<div class=""><br class="">
</div>
<div class="">Petr, Francois is right in his comment as to what I
refer to. </div>
<div class="">I thought about the ucd usage of it, perhaps this is
something to look into. </div>
<div class=""><br class="">
</div>
<div class="">I guess the options/questions are: </div>
<div class="">1) add a column for that and add a vocabulary </div>
<div class="">2) use the field semantics and have a controlled </div>
<div class=""><br class="">
</div>
<div class="">In both cases it points to a vocabulary, and I would
vote for 2 in principle since it looks like it would require
less effort. </div>
<div class=""><br class="">
</div>
</blockquote>
<br>
Petr 2019-10-12 to all<br>
<br>
<blockquote type="cite">thanks for explanation - I was thinking
about more complex cases than he end point of datalink (e.g.
animation of datacube)
<br>
in this case we had a problem to describe the link of our example
pointing from individual photometry point to the original image
<br>
We used a SIAPLink with accesURL - as this was understood by
Aladin.
<br>
<br>
the semantics makes sense and its controlled vocabulary as well..
<br>
just I still see philosophical issue with the definition of time
<br>
<br>
to fit powerspectra frequencies etc ....
<br>
<br>
so it may be timeseries of (in principle) datacubes - spectra and
images are degenerated datacubes ...
<br>
<br>
as an ordered set of entities - eg files in directory havin
timestamp
<br>
<br>
<br>
which is diffeent from the time transformation- like
<br>
associate the timeseries with its power spectrum
<br>
<br>
Kepler case e.g.
<br>
<br>
how to work with this ?
<br>
</blockquote>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="moz-cite-prefix">Le 15/10/2019 à 17:28, François
Bonnarel a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:688e6936-c43a-c183-19f5-91854a78b3ce@astro.unistra.fr">Dear
all,
<br>
<br>
Following the discussions last week and mainly the question of
tagging TimeSeries attached to sources in a catalog via DataLink I
make a proposal using the draft mechanism of "VEP" (vocabulary
enhancement proposal) proposed by Markus in the
<br>
<br>
draft "Vocabularies in the VO version 2.0 -2019-07-15"
<br>
<br>
AssociatedDataSet is a new branch. Children are
Associated-image, Associated-spectrum, etc... as requested
recently By Alberto Micol or Carlos Rodrigo.
<br>
<br>
and Associated-TimeSeries. As requested by Ada during the
interop I added a few children to Associated-TimeSeries (so
grand-children to Associated-Data) : Associated-Lightcurve,
Associated-TilmeSeries-spectra, etc ...
<br>
<br>
You will find this so-called "VEP" here :
<br>
<br>
<a class="moz-txt-link-freetext" href="https://wiki.ivoa.net/twiki/bin/view/IVOA/WebHome?topic=VEPs">https://wiki.ivoa.net/twiki/bin/view/IVOA/WebHome?topic=VEPs</a>
<br>
<br>
Cheers
<br>
<br>
François
<br>
<br>
<br>
<br>
<br>
</blockquote>
<br>
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