A former colleague once
introduced
University of Maryland mathematician
James A. Yorke as "the man who brought chaos to
mathematics."
It wasn't a criticism. Tuesday it was announced that Yorke will
share
the
2003 Japan Prize in science and technology for his pioneering work
in
the
relatively young mathematical field of
"chaos" theory.
His theoretical research, and that of his multidisciplinary Chaos
Group
at
Maryland's In stitute for Physical Science and Technology, is now
being
used to illuminate complex real-world problems as diverse as
infectious
disease transmission, weather forecasting and population changes
in
biological systems.
The Japan Prize, announced Tuesday in Tokyo, carries a $412,000
cash
award. It is also an international honor highly regarded by
scientists,
who rank it just below the Nobel Prize and the Fields Medal in
mathematics.
University of Maryland officials called Yorke's selection the
highest
honor received by a professor for work at College Park since
historian
Louis Harlan won a 1984 Pulitzer Prize for his biography of
Booker
T. Washington.
Unexpected honor
"It was a total surprise," Yorke said of the news that
he had
won. "A
Spanish physicist had told me he was nominating me, and I told him
not
to
bother. I didn't think I had a prayer."
Yorke said he plans to ask the Japan Prize foundation to give a
third
of
his share of the cash prize to the University of Maryland, to seed
further
research.
UM President C.D. "Dan" Mote Jr. called Yorke's
achievement
"a distinction
as great as any in the world. I am so pleased for him and for
the
inspiration his recognition will provide for others."
Yorke, 61, of Columbia, will share the honor (and split the
cash) with
Yale mathematician Benoit Mandelbrot, who is being honored for his
work
in
the study of fractals, complex natural shapes that repeat
themselves at
different scales.
Two Japan Prizes are awarded each year in diverse fields. The
second
for
2003 was given for "visualizing techniques in
medicine." It
will go to
Japanese scientist Seiji Ogawa, for his groundbreaking work in
functional
magnetic resonance imaging, now used widely in medical research
and
diagnosis.
Previous Japan Prize winners have included Robert C. Gallo, now
director
of the Institute for Human Virology, at the University of
Maryland
Biotechnology Institute, for his co-discovery of the HIV
virus; Timothy
Berners- Lee, inventor of the World Wide Web; and Dr. Donald
A. Henderson
of Johns Hopkins University, for his work with others in
eradicating
smallpox.
Likened to Nobel
"The Japanese are rather disappointed this [award] isn't
better
known. It's their own Nobel Prize," said Bill Blandpied, who
until
this
year directed the National Science Foundation's Tokyo
office. "Among
scientists it is very highly prized, very prestigious, and they
[the
Japanese] make a big show of it."
This year's honorees will receive their awards in April at
elaborate
ceremonies in Tokyo. The Japanese emperor and empress, the prime
minister,
other national leaders, diplomats and previous winners are
expected to
attend.
Japan Prize laureates are selected each December by the Science
and
Technology Foundation of Japan for work that has "advanced
the frontiers
of knowledge and served the cause of peace and prosperity for
mankind."
Science of complexity
Yorke and Mandelbrot were honored for their work in the
"science
and
technology of complexity."
"The world we live in is so complex that it is an enormous
challenge
to
understand the fun damental nature of its complexities," the
selection
committee said. Yorke and Mandelbrot "have provided new
frameworks
for
understanding complex phenomena, and have defined both their
foundations
and their applications."
Northwestern University math professor John Franks said
scientists once
presumed the natural world was "deterministic" -- that
is, predictable
once you had the formulas to describe it. Planetary motions, for
example,
are predictable.
When they saw randomness, they assumed it was the result of a
flawed
experiment. "The insight for which Yorke is substantially
responsible
is
that this is not the case," Franks said.
Chaos theory attempts to describe "nonlinear" phenomena
--
those in which
small changes, or differences in initial conditions, lead quickly
to large
dif ferences and seemingly random and unpredictable consequences,
such
as
the weather and the stock markets.
Such systems began to get attention a century ago. But their
importance
was not appreciated until digital computers became capable of
simulating
and demonstrating their behavior. Yorke coined the use of the term
chaos
to describe such systems in a paper written in 1975 with
T.Y. Li.
"I like to say that the last people to understand chaos were
the
scientists," Yorke said. "Everybody knows their lives
are chaotic.
This is
because we know that small changes precede huge changes."
For example, he said, each individual child is the
unpredictable
consequence of an infinite number of chance occurrences and
small
decisions, from those that led to the parents' first meeting, to
the
winner in the race among millions of individual sperm toward the
egg.
In meteorology, forecasters take many readings of temperature,
pressure
and other conditions around the world. But they make assumptions
about
millions more they can't directly measure. The uncertainties
quickly
multiply.
"After 36 hours," he said, "the two predictions
will be
twice as far apart
as the initial guesses, on average. And every 36 hours they get
twice
as
far apart. This is the nature of chaotic models."
"Predicting the weather -- whether it's going to be rainy or
sunny
a month
ahead -- is basically impossible," he said.
Yorke's Chaos Group is working with the National Weather Service
to
improve the performance of computer forecast models, which start
with
similar assumptions but rapidly diverge. His team is looking for
ways
to
check the models' performance against newly observed weather
data. The
conditions assumed by the least-accurate models can then be
recalibrated
to drag them back into alignment with the best, narrowing the
forecast
error.
Yorke's group is also using what it has learned about complex and
chaotic
systems to improve predictions for the spread of infectious
diseases,
such
as AIDS, and to increase the efficiency of the decoding of the
human
genome.
"We're just looking for fascinating problems," he
said.
James C. Alexander, chairman of the math department at Case
Western
Reserve University, once worked with Yorke at Maryland. He said
Yorke's
multidisciplinary Chaos Group "has a national and
international reputation
as a place where interesting science is done."
"He's generated an enormous number of ideas," Alexander
said.
"A lot of
these ideas come from bouncing ideas back and forth with people,
so they
get involved."
Physics and math
Yorke received his bachelor's degree from Cornell University in
1963
and
his doctorate in math from Maryland in 1966. He directed UM's
Institute
for Physical Science and Technology for 16 years before stepping
down
last
year.
He now holds the title of Distinguished University Professor, the
only
UM
faculty member ever to hold dual appointments in physics and
math.
A fan of science fiction since the fifth grade, Yorke likes to
listen
to
sci-fi books on audio tape while he drives or walks for
exercise. He is
married and has three grown children.
His wife, Ellen, is a medical physicist working in radiation
medicine
at
Memorial Sloane-Kettering Cancer Center in New York.
Copyright 2002, The Baltimore Sun
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