<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<p>Dear all,</p>
<p>This is a follow-up of these two emails</p>
<p><a class="moz-txt-link-freetext" href="http://mail.ivoa.net/pipermail/dm/2017-July/005583.html">http://mail.ivoa.net/pipermail/dm/2017-July/005583.html</a></p>
<p>and</p>
<p><a class="moz-txt-link-freetext" href="http://mail.ivoa.net/pipermail/dm/2017-July/005594.html">http://mail.ivoa.net/pipermail/dm/2017-July/005594.html</a></p>
<p>which are discussing chapter 4 of TimeSeries Data Model IVOA note
within the scope of the TimeDomain effort summarized by Ada there:<br>
</p>
<p><a class="moz-txt-link-freetext" href="http://mail.ivoa.net/pipermail/dm/2017-July/005581.html">http://mail.ivoa.net/pipermail/dm/2017-July/005581.html</a><br>
</p>
Discussed issue: do we need ND-points or not ?<br>
<br>
Reference : Laurent's diagram in email
(<a class="moz-txt-link-freetext" href="http://mail.ivoa.net/pipermail/dm/2017-July/005581.html">http://mail.ivoa.net/pipermail/dm/2017-July/005581.html</a>) and CubeDM
draft from
<a class="moz-txt-link-freetext" href="http://volute.g-vo.org/svn/trunk/projects/dm/CubeDM-1.0/doc/WD-CubeDM-1.0-20170203.pdf">http://volute.g-vo.org/svn/trunk/projects/dm/CubeDM-1.0/doc/WD-CubeDM-1.0-20170203.pdf</a>
(last version)<br>
<br>
In figure 4 of Jiri's note, SparseCube doesn't relate to the
ND-point class as it is the case in the IVOA sparse cube data model
project.<br>
<br>
The ND-point class gathers several DataAxis (or Observable)
containers for measurements on a given data Axis to represent a
"point" or "event" in the data space.<br>
<br>
On Jiri's figure a set of "CubeAxis" is directly related to
"SparseCube". This doesn't imply explicitly a relationship between
each of these "CubeAxis" instances and doesn't even imply that each
of these "CubeAxis" will have the same number of instances.<br>
<br>
So I am wondering if we should not reintroduce the ND-point feature
between "SparseCube" and "CubeAxis" or "DataAxis". What do you think
?<br>
<br>
François (after discussions with Laurent, Mireille and Ada on this
topic)<br>
<pre wrap="">
</pre>
<br>
<br>
<br>
<div class="moz-cite-prefix">Le 12/07/2017 à 10:57, Mireille Louys a
écrit :<br>
</div>
<blockquote
cite="mid:77f3160e-f7f0-981c-4808-7453c39b46f3@unistra.fr"
type="cite">
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<font face="Times New Roman, Times, serif">Dear DM and Time Domain
followers,</font> <br>
<br>
<font face="Times New Roman, Times, serif">I am trying, together
with my CDS colleagues, to recap on the various DMs available
in the IVOA and understand the possible links between the future
Time Series Model ( as sketched in Jiris's Note) and existing
DMs like ND-Cube and STC 2.<br>
<br>
Here is a graph proposed by Laurent Michel to clarify the links
in 3 main parts : <br>
</font>
<ul>
<li><font face="Times New Roman, Times, serif"><i>DataSetMetadata
DM</i>, which has the main ObsDataset Class ,</font></li>
<li><font face="Times New Roman, Times, serif"><i>ND-CubeDM</i>,
which defines a SparseCubedataset</font></li>
<li><font face="Times New Roman, Times, serif"><i>TimeSerieCubeDM</i>,
which highlights the special properties of a Cube depending
on a Time axis</font></li>
</ul>
<font face="Times New Roman, Times, serif">I think this is
essential to highlight the inheritance path between these 3 DM
building blocks: <br>
a TimeSeriesCube <is a > NDCubeDM::SparseCubeDataset<br>
</font>a <font face="Times New Roman, Times, serif"><font
face="Times New Roman, Times, serif"><font face="Times New
Roman, Times, serif"> NDCubeDM::</font>SparseCubeDataset </font></font><font
face="Times New Roman, Times, serif"><is a >
DatasetMetadaDM::ObsDataset<br>
</font><br>
<font face="Times New Roman, Times, serif"><font face="Times New
Roman, Times, serif">ObsDataset has a <i>dataproduct</i><i>_</i><i>type</i>
attribute which allows to discover all dataproducts of type '
timeseries'. <br>
this provides the container object for time-dependent data.<br>
<br>
If we need to select <i>timeseries dataproducts</i> according
to some properties extracted from their data we can:<br>
- reuse what <font face="Times New Roman, Times, serif">Obscore
DM provides to explain general axes properties<br>
</font></font></font><font face="Times New Roman, Times,
serif"><font face="Times New Roman, Times, serif"><font
face="Times New Roman, Times, serif"><font face="Times New
Roman, Times, serif"><font face="Times New Roman, Times,
serif">target_<font face="Times New Roman, Times, serif">name</font>,
s_region, </font></font><font face="Times New Roman,
Times, serif"><font face="Times New Roman, Times, serif"><font
face="Times New Roman, Times, serif"><font face="Times
New Roman, Times, serif">s_resol, </font></font>t_min,
t_max, t_resol, em_min, em_max, em_resol, etc. are the
basic properties for discovery<br>
<br>
</font></font> </font>- provide a richer description of
the <font face="Times New Roman, Times, serif">T</font>imeAxis
a<font face="Times New Roman, Times, serif">nd Observa<font
face="Times New Roman, Times, serif">ble<font face="Times
New Roman, Times, serif">Axis</font></font></font>. <br>
For that , extracting a statistical profile from the data
contained in the Cube could do the job. <br>
<font face="Times New Roman, Times, serif">this means to </font>access
and analyse the Data part in ND-Cube , i. e the ND-Points
gathered in a SparseCube Object<br>
</font></font><font face="Times New Roman, Times, serif"><font
face="Times New Roman, Times, serif"><br>
I guess more properties can be exposed to qualify the axes
present in the Timeseries dataset , but for the moment , I see
some overlap of notions between <br>
CharacterisationDM::ObservableAxis, STC2.0::CoordMeasurement
(??) and TimeSerieCubeDM::CubeAxis.<br>
<br>
This would be great if we could sort this out, <br>
but currently , I would appreciate your feedback on the
attached diagram , in order to proceed on the data model
structure. <br>
<br>
Cheers, Mireille ( after discussions together with Laurent,
François, Ada) <br>
<br>
</font></font>
<pre class="moz-signature" cols="72">--
--
Mireille Louys
CDS Laboratoire Icube
Observatoire de Strasbourg Telecom Physique Strasbourg
11 rue de l'Université 300, Bd Sebastien Brandt CS 10413
F- 67000-STRASBOURG F-67412 ILLKIRCH Cedex
tel: +33 3 68 85 24 34</pre>
</blockquote>
<br>
</body>
</html>