Science Archives in the 21 Century:

jellytrickInternet and Web Development

Nov 10, 2013 (3 years and 7 months ago)

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LAMBDA

is a thematic data center focusing on serving cosmic
microwave background (CMB) data to the research community. Data
from the following missions are served:


Wilkinson Microwave Anisotropy Probe (
WMAP
)


COsmic Background Explorer (
COBE
)


Infrared Astronomical Satellite (
IRAS
)


Submillimeter Wave Astronomy Satellite (
SWAS
)


CMB suborbital experiments.


Community Requirements:

CMB data is unlike other astrophysical data, consisting of:


Intrinsically diffuse surface brightness photometry.


Extremely faint signal levels: one part in 100,000 relative to the
uniform background.

Most users perform full sky analysis as opposed to partial sky or point
source analysis.

The nature of this data requires detailed knowledge of the instruments
used in order to successfully use the data.

The number of data sets in this field is not large; however, these data
sets are becoming large and complex. This is a tendency that will
increase as the polarization experiments currently being deployed
begin producing data.











WMAP Q
-
Band skymap, scaled from
-
200 to 200
µK from the 2.75K background


Data is typically stored and supplied in FITS or ASCII format as
appropriate. These are the standards for this type of data and
therefore the most convenient for the users of the site.


LAMBDA Staff:

Gary Hinshaw (NASA, Director)

Michael Greason (Adnet Systems)

Britt Griswold (Infonetic)

Paul Butterworth (Adnet Systems)

Urmila Prasad (Adnet Systems)

Janet Weiland (Adnet Systems)


LAMBDA’s Implementation:


Dell PowerEdge 4600, 2 Hyperthreaded 2.4GHz CPUs, 2GB RAM,
4.5TB disk space (configured as six RAID 5 filesystems).


Backups: StorageTek SL
-
500 LTO
-
3 tape library using Legato
Networker 7.3 (shared with WMAP)


RedHat Enterprise Linux 4 ES


Apache Web server 2.2.4


ColdFusion 7


MySQL 4.1.20


3 FTE’s


The
LAMBDA

web site is constructed using the ColdFusion Markup
Language (CFML), a scripting language. This confers several
advantages:


Consistent appearance and behavior across the entire site is
maintained by consolidating formatting to a small collection of custom
tags. Site maintenance is greatly simplified by this architecture.


Development of new pages is greatly simplified. By encapsulating
formatting into a set of tags, the author only needs to worry about
individual page content.


An easy to use database interface is built into the language, allowing
the ready generation of dynamic pages.























WMAP Product Web Page: The tables of data products may be collapsed and
expanded to allow the user to make efficient use of screen real estate. It is
generated from data in a MySQL database using a CFML custom tag; the page
simply supplies arguments to the tag to select output. This page is representative
of the data product listings and of the data download pages


Analysis Tools:

LAMBDA

has developed several tools for the CMB community; it also
provides links to a collection of tools developed by other research
groups. A contributed software archive has also been opened (and is
served from a web site at JHU) that facilitates the sharing of tools
between members of the community.















Screen shot of LAMBDA’s skyviewer tool. This tool permits viewing of HEALPix
-
formatted skymaps on a 3D sphere or in a Mollweide projection.



LAMBDA’s strengths:



It is a small, focused data center catering to a specific segment of
the astronomical community. The specific needs of this important
area of research are readily targeted, and changes in needs can be
quickly adapted to.


It is run by and has easy access to many of the leading researchers
in the field of cosmology.


It has a simple, easy to navigate design that can be readily modified
as needs change.


Some Problems:


SPAM! An archive of questions received and responses is
maintained; in the last few months, a flood of spam has necessitated
the addition of a filter.


Acquisition of data from small project scientists. Convincing
scientists to allow their data (as opposed to simply the results) to be
served is frequently difficult.


In terms of manpower,
LAMBDA

is quite small. This isn’t a problem
when dealing with day
-
to
-
day operations and maintenance; nor is it a
problem during data ingest. However, it can make it difficult to deal
with requirements imposed from outside.

Science Archives in the 21
st

Century:

NASA’s Legacy Archive for Microwave Background Data Analysis (LAMBDA)

Paul Butterworth, Adnet Systems Inc., Code 665, NASA/GSFC, Greenbelt, MD 20771

(301) 286
-
1850, Paul.S.Butterworth.1@gsfc.nasa.gov