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The obscure subject of game theory has become better known, now that Prof. Robert (Yisrael) Aumann of The Hebrew University has shared a Nobel Prize in Economics on the basis of his work in this field. Obviously, game theory is not a hobby for children. Now Technion researcher (and former Moledet MK) Prof. Shaul Gutman says he has discovered a mathematical approach to hitting maneuverable targets and succeeded in implementing game theory for directing guided missiles to their targets.
Gutman's new book on the subject - published by the American Society for Astronautics and Aeronautics and the result of 25 years of work - was written "from the missile's viewpoint," says its author. Although the book takes the standpoint of the pursuer, Gutman explains, the approach is equally applicable to the target.
"It is the first book dealing with guidance laws for homing missiles, as an outcome of a 'conflict' between a missile and a target. In such a game, the missile tends to minimize the miss-distance using proper pursuit maneuvers, while the target tends to maximize it using evasive maneuvers." Gutman adds that in the past, it was difficult to account for the fact that missiles have a limited ability to maneuver. As a result, the standard guidance law was unable to guarantee a direct hit.
"Using the property known as the saddle-point in game theory, we are able to design a guidance law or algorithm - stored in the missile computer - that guarantees a narrower miss, and eventually hit-to-kill, regardless of the target's maneuvers. Moreover, this game approach helps to better design the airframe and autopilot to achieve this goal," he says.
Although Poland was the nation with the largest number of Jews to perish in the Holocaust, and the location of many devastating pogroms, it has also been a good home for Jews over many of the nearly 1,000 years they have lived there. Diplomatic ties with Israel were halted by Poland in 1967 and renewed in the 1990s. Today, relations are excellent, and scientific ties are strong.
This was demonstrated recently when Jan Wocjciech Piekarski, Poland's ambassador to Israel, attended a reception on The Hebrew University's Mount Scopus campus. Speaking in Hebrew, English and Polish, the ambassador awarded unusual honors to three veteran HU researchers, as university president Prof. Menachem Magidor looked on. The ambassador noted that there are frequent exchanges of scholars between the two countries, with joint research projects, and that Polish universities have centers devoted to Jewish history and culture.
Prof. Renata Reisfeld, the Enrique Berman Professor Emeritus of Solar Energy, received an honorary professorship from the Polish National Academy of Science; emeritus professor history Prof. Jacob Goldberg was elected a foreign member of the Polish National Academy of Science; and Dr. Shela Gorinstein of the School of Pharmacy received the Cavalier Cross of the Polish Order of Merit, becoming the first Israeli ever to receive this honor from the Polish president.
Poland-born Reisfeld, who moved to Israel half a century ago, has done extensive research on sol-gel glasses, solid-state visible lasers, luminescent solar concentrators and energy transfer. Two decades ago, she was invited to lecture on rare-earths spectroscopy in Poland, even though the hosts didn't know she had been born there and speaks the language fluently. Her appearances led to close cooperation with scientists and regular visits. Goldberg, also a Polish native, has been honored by various Polish institutions, and has done research on Poland and Polish Jewry. Gorinstein, who was born in Russia and immigrated more than three decades ago, has achieved fame for her research on the health benefits of various beverages, vegetables and fruits, from garlic and beer to persimmons and grapefruits. She too has closely collaborated with Polish researchers.
NOT A WICKED ENCYCLOPEDIA
Everybody knows you can't trust a lot of the information on the Internet due to vested interests and amateur writers - but how about online encyclopedias? A new study published in Nature has compared the accuracy of science entries in the free Internet encyclopedia called Wikipedia (www.wikipedia.org), whose entries are written and donated by anyone who wishes, and those in the Encyclopedia Britannica. The study concluded that the accuracy of Wikipedia entries is not markedly less than those in the Britannica.
Despite the controversial approach of including information that anyone can write or edit, each of the 42 Wikipedia entries analyzed averaged only four inaccuracies, while Britannica's articles on the same science topics averaged three (including factual errors, critical omissions or misleading statements.
Nature also surveyed more than 1,000 scientists who had recently published papers in the journal to find out what they knew about Wikipedia. More than 70 percent had heard of it, and 17% of those consulted it on a weekly basis. But fewer than 10% of those aware of the Web site actually contributed their expertise by updating entries. Jimmy Wales, Wikipedia's cofounder, says its quality could improve even further if more scientists got involved. In a related editorial, Nature urges its readers to do just that.