| The
Experiment
The Viento project integrated two large-scale simulation
models running on supercomputers in geographically disparate
locations, communicating using the NASA ACTS satellite.
The first model -- running primarily at the National
Center for Atmospheric Research (NCAR) in Boulder, Colorado
-- uses atmospheric conditions as input to simulate
changing weather conditions over Lake Erie.
The second model -- running at the Ohio
Supercomputer Center (OSC) in Columbus, Ohio --
uses the changing Lake Erie weather conditions to predict
the evolution of physical lake conditions.
A third site -- at the Great
Lakes Environmental Research Laboratory (GLERL)
in Ann Arbor, Michigan -- provided input data and feedback
from scientists. By exchanging boundary data between
the models, the models worked together to provide forecasts
of changing weather patterns around Lake Erie.
The
Satellite
The Advanced Communications Technology Satellite (ACTS)
is the main focus of NASA's program to provide high-speed
telecommunications resources. Originally planned in
1979, the satellite was placed in a geosynchronous orbit
at 100 degrees west longitude in September 1993.
There are three stationary beams, focused on:
Cleveland, Atlanta, and Tampa, and two hopping beams
serving two distinct sectors. One of the beams can hop
to six discrete locations, and the other beam can hop
to seven discrete locations. The total throughput of
the satellite is 660 Mb/second, and can be accessed
at full speed using a High Data Rate (HDR) ground station
in a single location, or can be multiplexed to communicate
with 4 155 Mb/second channels in four different locations.
Networking
HDR ground stations located at NCAR and at OSC are connected
through a HiPPi switch to both the supercomputers and
Silicon Graphics Crimson VGXT workstations. A DS-3 land
line connected OSC and GLERL during the experiment.
Visualization
Ohio State University's Advanced Computing Center for
the Arts and Design (ACCAD) provided scientific visualization
support for the Viento project. They utilized Silicon
Graphics' "Explorer" visualization software
in displaying two- and three-dimensional still images
and animated sequences built from the data generated
by each computational model in the experiment.
Collaboration
Audio and video cards installed in each workstation
provided images and voice of each scientist at each
workstation during the experiment. Additionally, collaboration
software -- NCSA Collage, for example -- provideed an
interactive "whiteboard" environment for displaying
text and images between sites.
Related
Project Information:
The MISSION Project
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