## Two Berkeley Lab Mathematicians Awarded Prestigious Math Prizes

Two mathematicians from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory have won prestigious prizes from the International Council for Industrial and Applied Mathematics (ICIAM) for groundbreaking work in applied math, with impacts ranging from fluid mechanics and aerodynamics to medical imaging and semiconductor manufacturing.

Alexandre Chorin won the 2011 ICIAM Lagrange Prize in recognition of his fundamental and original contributions to applied mathematics, fluid mechanics, statistical mechanics, and turbulence modeling. The Lagrange Prize provides international recognition to mathematicians who have made an exceptional contribution to applied mathematics throughout their career.

James Sethian won the 2011 ICIAM Pioneer Prize for his fundamental methods and algorithms that have had a large impact in imaging and shape recovery in medicine, geophysics and tomography, and drop dynamics in inkjets. The Pioneer Prize recognizes pioneering work introducing applied mathematical methods and scientific computing techniques to an industrial problem area or a new scientific field.

The awards, announced today by the ICIAM, bring to Berkeley Lab two of the five math prizes the organization awards every four years. The ICIAM is composed of many of the national and international associations of professional mathematicians concerned with applications.

Chorin is a senior scientist with the Mathematics Group of Berkeley Lab’s Computational Research Division and a University Professor of mathematics at the University of California, Berkeley. Sethian heads the Mathematics Group of Berkeley Lab’s Computational Research Division and is a professor of mathematics at the University of California, Berkeley. They are two of the world’s foremost applied mathematicians and have spent most of their careers at Berkeley.

“These awards recognize the immense influence that Alexandre’s and James’ research has had on applied math as well as many scientific disciplines and industrial applications,” says Horst Simon, Deputy Director of Berkeley Lab. “The awards are also a testament to Berkeley Lab’s worldwide leadership in applied math, benefitting society and solving some of our most urgent scientific challenges.”

#### Chorin’s contributions span computational mathematics, fluid mechanics, statistical mechanics, and turbulence** **

In a career that spans nearly 50 years, Chorin introduced mathematical and computational methods for solving problems in science and engineering. He has applied his methods to understanding water flow in oceans and lakes, flow in turbines and engines, combustion, and blood flow in the heart and veins.

He invented techniques in the mid 1960s that were the first practical and accurate methods for approximating the full Navier–Stokes equations, which stand at the basis of the most popular codes in computational fluid mechanics.

Chorin followed this with the invention and design of vortex methods, for which he was given the U.S. National Academy of Sciences Award in Applied Mathematics and Numerical Analysis in 1989. These techniques made possible the modeling of the complex mixing and instabilities of turbulent flow.

More recently, Chorin developed methods for distilling fundamental properties buried in noisy and uncertain data. One application is designed to extract biological information from satellite imagery of the ocean.

The ICIAM news release states, “Beginning with his pioneering work 40 years ago, Chorin developed some of the key mathematical and algorithmic ideas that underlie many of the most powerful computer codes in computational fluid dynamics, by blending mathematical intuition, physical insight and a deep attention to practical implementation.”

His many awards include Norbert Wiener Prize in Applied Mathematics from the American Mathematical Society and the Society for Industrial and Applied Mathematics, which he received in 2000. He was honored with the title of University Professor by the Regents of the University of California in 2002. He is a member of the National Academy of Sciences and a fellow of the American Academy of Arts and Sciences.

Chorin, 72, was born in Poland and grew up Israel and Switzerland. He received his PhD from the Courant Institute of New York University in 1966 and joined Berkeley Lab in 1975.

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#### Sethian’s contributions range from fluid interfaces to computer chips

For the past three decades, Sethian has built mathematical and computational tools to tackle pressing problems in fields such as medical imaging, seismic imaging, combustion calculations, computer chip manufacturing, and inkjet printing.

The broad reach of his applications stem from his pioneering work on the computer representation of the motion of curves, surfaces, interfaces, and wave fronts, for which he was awarded the Norbert Wiener Prize in 2004.

According to the ICIAM news release announcing the award, the level set method pioneered by Sethian and Stanley Osher has had a major impact in a wide range of fields and is one of the most used algorithms of the past few decades.

Sethian’s mathematical algorithms for modeling etching and deposition in the manufacture of computer chips are now an indispensable part of industrial semiconductor fabrication simulations throughout the world.

Sethian’s algorithms for imaging and shape recovery are found throughout medical and biological imaging technologies, including imaging workstations that quantify cardiac motion and efficiency.

He developed tools for solving Hamilton–Jacobi equations with applications in geophysics and tomography, currently in use by the petroleum industry. He also developed numerical methods for inkjet dynamics and combustion processes.

The ICIAM news release adds, “This extraordinary range of successes is made possible by Sethian’s unparalleled eagerness to learn thoroughly the engineering aspects of problems he works on, the accuracy and depth of his feeling for mathematical structure, and his broad mathematical knowledge. His body of work is emblematic of what an applied mathematician should aspire to achieve.”

Sethian, 56, was born in Washington, D.C. He earned his PhD in Applied Mathematics from the University of California, Berkeley in 1982 and joined Berkeley Lab in 1985. He is a member of the National Academy of Engineering. ** **

The prizes will be awarded at the International Congress for Industrial and Applied Mathematics next July in Vancouver, Canada.

Chorin’s and Sethian’s research has been funded in part by the Department of Energy’s Applied Mathematics program, which is part of the Office of Advanced Scientific Computing Research.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research for DOE’s Office of Science and is managed by the University of California. Visit our Website.

**Additional information: **

- ICIAM information about 2011 prizes
- Alexandre Chorin’s research
- James Sethian’s research

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