[mmaimcal]Re: configurations

[Bryan Butler]

all,

i'm a bit hesitant to make an 'official' scorecard.  it makes it look
like there is a real _competition_ between particular designs.  is this
what we want to promote?  i would also think that the panel members would
want to come up with their own versions, rather than having one dictated
to them...

if forced to do so, however, i would make a scorecard more thusly:

1 - science

   does it meet the PDR recommendations on resolution, UV sampling, etc?
   (compact array should maximize brightness sensitivity; intermediates
   should have gaussian uv density; extended should have maximum resolution
   without forcing any fiber runs > 25 km)

   beam metrics

   uv metrics

   simulation results

2 - cost

   number of pads minimized (this is really a bit of a red herring though,
   until we have better cost estimates for foundations as a function of
   location on the site)

   is there apparent difficulty getting to some locations (implying longer
   roads and cable runs)?

3 - operations

   is one design easier to operate and maintain than another?

4 - flexibility & robustness

   how robust is the overall design philosophy to changes?

   how robust are particular designs to antennas being dead or pads being
   unusable?

   is the configuration style flexible ('fixed' vs. 'flowing' types)?

   are the 'hybrids' reasonable - including N-S elongation, and the
   hybrid between the largest intermediate and the extended configuration?

   what about 'multi-configuration' (which loses some of its meaning in
   the 'flowing' antenna move style) capability?


you can argue about the contents of each of the 4 categories, but i'm
pretty sure that the above 4 are the ones that really need to be compared
to each other when deciding on the configuration, both in design philosophy
and in the particular design.  this is nothing new, others have been pointing
all of this out for years - i have just put it into the 'scorecard' 
formalism...


	-bryan


On 2002.01.16 10:05 Al Wootten wrote:
> David Woody writes:
>  > Hi Al
>  > I looked at the pad locations.  The three proposals
>  > contain all of the ~250pads, but only Boone gives
>  > the information necessary to determine which pads
>  > to use with each configuration.  Could you have
>  > John and Adrian list the pads to be used for each
>  > separate configuration?
> Stephane requested this information also; I have asked that
> they forward it to me for distribution to the committee.
>  > Also Boone's largest configuration seems to have
>  > only 54 antennas, all the rest have 60 antennas.
> 60 was what the PDR requested.  I had not noticed that about
> Boone's largest but I've been more focussed on the compact configurations
> just now.
> 
> We discussed the 'score card' yesterday.  We thought the following
> attributes might be elements of the score card:
> 
> Compact array design
> Extended configuration design
> simulations
> Beam metrics
> uv metrics
> Mutability:  suitability for extreme zenith angles/mosaicing at these angles
> No. pads
> Practicality/efficiency from operations viewpoint
> Elegance
> 
> To some extent these are all intertwined but it appeared to us that
> these were some key elements to be considered in rough order of
> importance.  Comments?
> 
> Thanks,
> Al
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