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Allocating Limited Resources in Data Representations
Trying to tease out relevant scientific information from the
huge volume of data produced by todays computers can be like looking for
a needle in a high-tech haystack. High-speed computers and the scientific
communitys increasing ability to make precise measurements creates more
data than anyone has time to sift through.
This is the problem that Dr. Peter Schröder and the team of
mathematicians and computer scientists he worked with tackled in their
KDI-funded project, Towards Ideal Data Representations. Dr. Schröder,
who was a co-project investigator on the project, is a professor of Computer
Science and Applied and Computational Mathematics at California Institute of
Technology (Caltech).
Dr. Schröder explains, "For example, there are satellites in
orbit around the earth that take high resolution imagerythese can be
photographs or measurements of topography. If we want to use some of this, say
for policy planning or for understanding the environmental impact of various
things, we need to analyze these data. And the sheer amount of data often makes
it very difficult to do so."
So the group that worked on this project set for themselves
the challenge of developing mathematical tools to find new representations of
these data and new ways to analyze and manipulate them. They expected that
these advances would accelerate progress in many different areas, from medical
imaging to particle physics to computer graphic simulations for Hollywood
movies.
The group kept in mind that mathematical theorems had to
lead to practical applications. According to Dr. Schröder, "To have a
partnership between people who have the background to prove the hard theorems
in mathematics and people who are more concerned with practical issues on the
computer science end of things made it possible for us to develop relevant
mathematics that you can actually put to work on real problems."
The team wanted to come up with a method for representing
data in a way that would help them allocate resources intelligently. They
captured that idea in a mathematically precise manner and then built algorithms
to exploit it. "In a digital photograph, for example," says Dr. Schröder,
"theres more detail in some areas and less in others. I want to allocate
more resourcescomputer resources, storage resourcesto the region
with a lot of detail. In regions where theres relatively less going on, I
can probably get away with allocating fewer resources."
The team focused on representations of different levels of
resolution in settings where data arent as neatly organized as in an
image. "An image is nice and regular," says Dr. Schröder. "But, say, if you
wanted to take temperature measurements on planet Earth, you might have
measuring stations that are distributed all over the place. They are not nicely
arranged in a grid of rows and columns and measurementsthey are
irregularly placed. We were able to build algorithms that can deal with
irregular data and get similar benefits as we did in those settings where
everythings nice and regular."
The team developed algorithms that turned out to be
practically relevant and performed far better than previous algorithms that had
not used the same mathematical ideas. The team also made prototype
implementations of their algorithms to demonstrate how well they perform.

Dr. Schröder credits the KDI grant with making this research
possible. He says, "One of the important struggles for academics like myself in
terms of taking good research questions is that I have to jump into the future
by a significant distance. And the KDI funding was very important for making
that possible. It provided support for pursuing ideas that look promising but
where lots of detail is yet unknown. It allowed these visions to be pursued more
intensely, quicker, deeper, and broader."
Today, Peter Schröders work involves computer
graphics, with a focus on multi-resolution methods for modeling, simulation,
and visualization. To learn more about his research, visit the Web site of the
Multi-Res Modeling Group at Caltech,
The Multi-Res Modeling Group has also designed software
prototypes, which are available to the public at
www.multires.caltech.edu/software/
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