Re: SETI like tass project

[Chris Albertson <chrisalbertson90278@yahoo.com>]

Tom,

With SETI there is a small "work packet" that can be transmitted in
a minute or so even using a modem.  On a typical PC each work
packet takes a tens of minutes to process.  So with SETI the ratio
of data transport to computation is very good.

With TASS the smallest "work packet" is one image which is
2K x 2k x 16 bits = 8M.  These typically compress _without_ loss
to about 6.5MB per image.
Still, It is reasonable, even with a modem to download one 6.5MB image
with many people doing the downloads an entire nights worth of
data could be reduced in under one hour.  BUT, (there is always
a "but") these images would have to be placed on a server that
has _very_ high bandwidth connection to the Internet.  The server
would need enough bandwidth to push one night's worth of the data
out each day.  Worse, it needs to be twice that fast at least,
if users aren't to see it as being uselessly slow and give up
on the downloads.  Still worse, the SETI-like clients will
likely NOT request data at a uniform rate but it will peak over
each 24 hour period.  We are talking "multi-megabits/second".
DSL or Cable modems just would NOT cut it for the server.  This is
possible but the cost of such bandwidth is about $1k/month.
We would flood even some university's Internet connections

There is also the possibility of using multiple image servers
but with multiple TASS camera sites this would be a given.
At any rate the "one night's data per day" requirement is a
demanding (and expensive) constraint.

Another option would be to install multiple computers at the
camera sites.  I can envision a "black box" with no keyboard
or CRT, just an Ethernet connection and power cord.(not even a
CDROM or floppy.) These "black boxes" connect to the local
Ethernet and request data, process it and send the results back.
They should be designed so that one could connect any number of
these black boxes to the same local Ethernet so the processing
rate would scale.  User training is minimized as there is only
one user control (the power switch.)

This would be the SETI model but using 100Mb/sec communication
media.  I think with current technology moving computers is
cheaper then moving data.



--- Tom Droege <tdroege2@earthlink.net> wrote:
> I have accumulated a lot of data.  About 375 CD's at this point.  I
> figure 
> another 1000 before the year is out.
> 
> I would again like to bring up the possibility of running a seti like
> 
> project to reduce this data.  Eventually we will have a well
> understood 
> pipeline.  It will be a big project to run all the data through it. 
> I am 
> prepared to do this myself and just set up a row of computers and
> shove CDs 
> through them.  But perhaps it would be fun to spread this around to a
> 
> team.  I know I brought this up before and got a good response.  Now
> I 
> could actually ship out data for analysis.
> 
> The start would be the engineering run data.  This will be 500-600
> CDs, of 
> order 30,000 images taken at 7.5 degrees N covering all hour angles. 
> Even 
> if the calibrations are not the best possible, there should be lots
> of new 
> variables in this data.  My bet is that there are a few thousand that
> have 
> not been measured before.  The engineering run contains both long and
> short 
> term data so we should find a wide range of periods.
> 
> Let's discuss how we might do this.
> 
> Tom Droege  
> 
> 


=====
Chris Albertson 
  Home:   310-376-1029  chrisalbertson90278@yahoo.com
  Cell:   310-990-7550
  Office: 310-336-5189  Christopher.J.Albertson@aero.org

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