The Mathematics of Megadisasters: BIRS talks with Florin Diacu

Posted on Fri, Dec 13 2013 11:38:00

Florin Diacu is a Canadian mathematician and author. He is currently a professor in the Department of Mathematics and Statistics at the University of Victoria, doing research in the field of dynamical systems. He is the recipient of the Best Academic Book Award in 2011 for his volume Megadisasters: Predicting the Next Catastrophe , the subject of his public lecture at The Banff Centre on November 14, 2013. This was the second talk in a series of joint Banff Centre/BIRS public lectures, which is part of The Banff Centre's Leading Ideas Speaker Series.

Diacu began research in celestial mechanics while completing his PhD thesis at the University of Heidelberg, Germany and focused on collisions between celestial bodies; however, the 2004 Indian Ocean earthquake and tsunami caused him to look elsewhere at mathematical models that affect the earth. That megadisaster killed close to 250 000 people and spurred questions relating to research on not only earthquakes and tsunamis, but also collisions of meteors with the earth, volcanic eruptions, rapid climate change, pandemics and stock market crashes, not all of which are as destructive, but nonetheless influence people’s lives significantly.

His book is written for the general public, and thus lends perfectly to this public lecture series. “I was mostly interested in telling people the state of the art relative to predicting these megadisasters. In most cases we have mathematical models that help us. In British Columbia, for example, we know that a big earthquake is coming and that it’s going to be the biggest disaster ever in North America (magnitude nine or higher). It could happen in 20 generations, but it could be any time. The problem is knowing what to do under such circumstances and how to recognize the signs.”

During his talk, Diacu gave an example of the benefits of being educated on warning signs. In 2004, a ten-year-old girl was with her family on a beach in Phuket, Thailand. The girl noticed that the sea looked bubbly and was reminded of a movie she had recently seen about the Hawaii tsunami of 1946, which depicted a similar phenomenon directly before the wave hit. Because she recognized the warning sign, the girl was able to warn her family and the lifeguard on duty, and save the lives of a 100 other tourists who were on the beach that day.

Diacu is currently on a panel that oversees a marine observatory near the coast of British Columbia and are working to implement an early warning system for earthquakes. “They cannot be predicted long in advance” he explains, “From the moment an earthquake is triggered until we get hit by the wave might be only ten to thirty seconds, but if a system is implemented we could, for instance, automatically stop or slow down trains to prevent them from derailing or stop gas supplies, as the pipes break during earthquakes and cause fires and explosions. We are trying to see exactly how a warning system might work, and then convince government and other private organizations to provide financial support.”

There were about 100 people in the audience for the lecture in Banff, a mix of about 40 mathematicians and 60 members of the general public. “With a talk like this you have to keep it general and supply many images and examples that the audience can relate to and understand without a background in the science. It is very rewarding because you know that people leave the room having learned something new and useful. And I find with this topic that there is so much interest and inquiry from the audience that the questions actually lasted longer than the talk.”

As a member of the PIMS executive at the time of BIRS inception, Diacu is very proud of how the organization has evolved. “We had originally thought to develop a site somewhere very isolated, but we gain much more by being at The Banff Centre because we can also interact with the people there. BIRS is not just mathematicians interacting with each other, but with the public lectures, plays, movies and concerts being held at The Banff Centre, and through this Leading Idea Series, BIRS is further able to contribute to that unique interaction between arts and science.”

Book: Magical Mathematics: The Mathematical Ideas That Animate Great Magic Tricks

Posted on Tue, Dec 03 2013 11:46:00

In their recently published book, Magical Mathematics: The Mathematical Ideas That Animate Great Magic Tricks, Persi Diaconis and Ron Graham – both mathematicians and a professional magician and juggler, respectively – reveal the “secrets of amazing, fun-to-perform card tricks – and the profound mathematical ideas behind them.” At BIRS, we particularly like the chapter, Is this Stuff Actually Good for Anything, which tackles the subject of Bruijn sequences, in which the authors include a section that provides a glowing review of the BIRS workshop, Generalizations of de Bruijn Cycles and Gray Codes, held in December of 2004.

The BIRS workshop was quite likely the first meeting of its kind to focus on the theory, constructions and generalizations of de Bruijn cycles, despite the fact that many people in diverse areas have been working on aspects of universal cycles of one kind or another for quite some time. Its intent was to give an overview of the various known results on de Bruijn sequences and universal cycles in general, and to exploit the diversity of the attendees in order to stimulate new work, focussing on several questions in which progress seems imminent or likely. According to Diaconis and Graham, BIRS provided an ideal setting for such interactions.

In their article, they describe how 25 researchers, including the likes of Brendan McKay (Australian National University), Eduardo Moreno (Universidad Adolfo Ibañez, Chile), Robert Johnson (Queen Mary University of London) and international experts including Hal Fredricksen (Naval Postgraduate School) who has over 40 years of experience in the field, Frank Ruskey (University of Victoria) who “has the world’s best programs for generating all kinds of de Bruijn sequences and Gray codes on his Web site” and Carla Savage (North Carolina State University), an expert on nonstandard constructions, came together in the “exotic location” of Banff, Alberta.

They go on to state how:

“There were really friendly introductory and expository talks aimed at bringing newcomers up to speed and making sure we were all on the same page. There were announcements of new results, big and small…Much time was spent in small groups where people go over special cases slowly and ask each other “silly questions” that might be embarrassing if asked in a large group.”

They also describe “one of the most spectacular new results [which] was Robert Johnson’s solution of the notorious ‘middle-layer’ problem” and how this particular problem relates to the magic behind their card tricks, stating that “Johnson’s result introduces new ideas and techniques that will surely be of help in other graph cycle problems.”

Diaconis and Graham conclude their article with a testament to the workshop’s success, citing progress made on old conjectures and new conjectures posed, but mostly, focusing on the community that was formed as a result of the time these researchers spent at BIRS. They state, “to find others who think this small world of problems is beautiful and important made a deep impression on all of us.”

P. DIACONIS and R. GRAHAM, Magical Mathematics: The Mathematical Ideas That Animate Great Magic Tricks, Princeton University Press (2012), 42-26.

Nov. 13th Public Lecture: Florin Diacu, "Megadisasters"

Posted on Wed, Oct 30 2013 17:06:00

New BIRS Brochure 2013

Posted on Fri, Sep 27 2013 18:06:00
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