VOEvent priorities

[Arnold Rots]

This misrepresents what I was saying.

I did not advocate putting everything into a massive WhereWhen (though
that would be an obvious solution).
I merely pointed out that SimpleTimeSeries does not follow adopted standards.
It could, with fairly minor restructuring and rewording.
Or one could adopt the light-weight table schema that I suggested.

Somehow, it seems to me that that message does not deserve a full
broadside from the chair that seems to be missing the mark as well.

  - Arnold


Rob Seaman wrote:
> Let me describe how this looks from the viewpoint of the chair.  While  
> nobody values a robust discussion more than I do (anybody want to  
> challenge that assertion?), engineering choices must be timely or they  
> risk becoming moot.  This is the central message of VOEvent-based  
> science, after all.
> 
> VOEvent is an IVOA standard, but the VOEvent community extends outside  
> of the IVOA context.  The people reading this email are the most  
> diverse of any IVOA WG - and yet we have found common ground where  
> other WGs have not, and done so time-and-again.  It concerns me that  
> some of our group have recently expressed private reservations about  
> the - hmm, how shall I say? - lack of timeliness of the IVOA process  
> in certain instances.
> 
> The goal in systems engineering is not to find the optimum solution -  
> it is to find a satisfactory solution and then to actually implement  
> it.  We should keep this goal of "satisficing" (yes, a real word) in  
> mind throughout our discussions.  I might (and have, on occasion)  
> recommend the same to other WGs.
> 
> VOEvent needs time series - which is to say that sufficient numbers of  
> our diverse user base need time series.  (And those who don't, needn't  
> use this v2.0 feature.)  A time series is a "thing" to be described  
> and so belongs in <What>.  Native STC usage in VOEvent is limited to  
> <WhereWhen> (where, for instance, orbital elements belong as targeting  
> coordinates for future observations).  So time series *in VOEvent  
> packets* will not use STC.  (And no, I don't see our combining  
> VOEvent's dependent variables with its independent variables into one  
> colossal <WhatWhereWhen> element.)
> 
> We will not embed the VOTable schema within the VOEvent schema, so  
> time series *in VOEvent packets* will not use VOTable.  VOEvent can  
> already reference external content including VOTables, but external  
> references do not address the need to embed simple time series in  
> transient alert packets.
> 
> On the other hand, the SimpleTimeSeries specification is satisfactory  
> - and can be made even more so through some small tweaks.  The team  
> that created SimpleTimeSeries has demonstrated that they are willing  
> to make said tweaks.
> 
> Thus, our best approach to a usable solution is SimpleTimeSeries.  We  
> undoubtedly passed by other potential solutions on the road from HTU-1  
> to today.  There is no convincing argument to discard SimpleTimeSeries  
> and turn around to pursue these now.
> 
> Now then, I thoroughly expect that the IVOA DAL group or some other WG  
> will pursue a "ComplicatedTimeSeries" specification at some point.   
> And perhaps in 3-5 years such a thing will exist - and perhaps it will  
> be based on STC or VOTable or both.  This will not be timely for our  
> purposes, and we have no way of knowing now whether the specification  
> resulting from such a process will be useful for our purposes.  If it  
> such a thing does add significant utility, then this can be supported  
> as a feature of a future VOEvent update.
> 
> By all means, let's challenge SimpleTimeSeries with how it might  
> support various VOEvent use cases.  We should use our efforts to  
> improve the solution on the table, not to saw the legs out from under  
> it.
> 
> Rob
> 
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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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