The branch of math that Daubechies developed, called wavelet theory, is used in such disparate realms as the streaming of Internet video, predicting earthquakes, and the precise delivery of radiation to cancer patients. Recently, Daubechies herself even used wavelets to help identify paintings by van Gogh.
Her concept is now so commonplace that engineers treat it almost as an everyday tool, like calculus. But when Daubechies published her seminal 1988 paper, while at the famed AT&T Bell Labs, it caused a sensation.
"It is probably one of the most cited papers in all of mathematics," said M. Victor Wickerhauser, a math professor at Washington University in St. Louis.
Like a sombrero
Wavelets are mathematical functions that look like the name suggests: small waves, or squiggles, that flatten out on either side. Wickerhauser, who was among those attending a workshop in Daubechies' honor Thursday morning at Villanova University, said they looked like the cross-section of a Mexican sombrero.
Daubechies, a native of Belgium who left Princeton University this year for a post at Duke University, did not invent wavelets, but her 1988 paper showed how the functions could be useful. She followed in 1992 with a book on the subject that is considered a classic in the field of applied mathematics. Writing about it in the journal Science, a reviewer raved: "The presentation is completely engrossing; it is like reading a good, thick Russian novel."
One of the main selling points of wavelets is that multiple functions can be added together to represent vast amounts of data in a more efficient manner. This technique is widely used to compress data for electronic transmission.
A digital photo with 20 megabytes of data, for example, can be compressed to one. The FBI used wavelets to store its vast library of fingerprints.
Not that you'll hear Daubechies (pronounced DOHB-shee) take much credit for it. Her husband, Robert Calderbank, recalled how her early wavelet lectures focused mostly on the contributions of others.
"It would seem to me that in a 55-minute lecture, she'd spend 50 minutes talking up other people," said Calderbank, a computer-science professor at Duke.
When Daubechies gave a speech at the Villanova workshop Thursday, she was no different, barely mentioning her own contributions. After a colleague introduced her by listing her accomplishments - membership in the National Academy of Sciences and awards too numerous to mention - she said: "I'd love to meet this person."
Daubechies was born in Houthalen, in western Belgium. Her father was a mining engineer, her mother a criminologist who worked with troubled youths. Her fascination with math manifested itself early on, even in the way she approached childhood pursuits.
When she sewed clothes for her dolls at age 8 or 9, for example, she enjoyed seeing how flat pieces of fabric could be joined to make something that followed a curved surface.
When she had trouble falling asleep at night, the young girl would compute the powers of two in her head: 1, 2, 4, 8, 16, 32, and so on, up to the billions, she said. Years later, when she met her husband, she was delighted to discover that he, too, had used this sleep-inducing technique as a child.
Daubechies attended an all-girls school in Belgium - which in retrospect she thinks may have been a positive, given that girls may not speak up as much when sitting alongside boys.
Today she is a strong supporter of women's advancement in her field, and helps to run an intensive summer program for women in mathematics at the Institute for Advanced Study in Princeton. The single-sex environment is empowering, she said in an interview.
"Women are very focused and very competitive, but they want to beat the problem," Daubechies said. "They don't want necessarily to beat the other person."
Indeed, she works with many from other disciplines - including the occasional work with her husband, the computer scientist - as wavelets are applicable in so many fields. Though she studied physics in college, she considers herself a mathematician. And yet her Franklin Institute award came in the field of electrical engineering.
You will just have to get someone other than her to tell you about it.
Contact staff writer Tom Avril
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