[新聞] 混沌理論之父病逝蝴蝶效應膾炙人口 < 聯合報╱編譯莊蕙嘉／綜合報導 >

看板TY_Research作者Morbert.時間17年前 (2008/04/18 20:42)推噓5(5推 0噓 0→)

留言5則, 5人參與討論串1/1

混沌理論之父病逝蝴蝶效應膾炙人口 < 聯合報╱編譯莊蕙嘉／綜合報導 > http://udn.com/NEWS/WORLD/WOR3/4305105.shtml 「混沌理論」之父、麻省理工學院教授愛德華．羅倫茲（ Edward Lorenz），十六日因癌症病逝於麻州劍橋家中，享壽九十。他提出的混沌理論，被譽為廿世紀最偉大的三大科學發現之一。混沌理論的主要精神是，在混沌系統中，初始條件的微小變化，可能造成後續劇烈改變。此理論最為人所知的論述之一是「蝴蝶效應」：一隻蝴蝶在巴西輕拍翅膀，可能引起一連串的大氣擾動，最後導致美國德州發生龍捲風。專長為氣象學的羅倫茲，發現混沌理論的過程就是一種「混沌現象」。一九六一年冬天，羅倫茲以電腦作天氣模擬，第二次運算時，為了省事，他從上一次模擬的中段開始，輸入第一次模擬結果列印出來的數據，讓電腦運算。差別在於，第一次的電腦運算結果，列印只顯示到小數點後三位的零點五零六，而非完整的小數點後六位、零點五零六一二七數字。這個遠小於千分之一的差異，造成第二次的模擬結果和第一次完全不同。羅倫茲從這個驚人的結果發現，準確預測天氣只是人類的幻想。他把這個發現寫成研究論文，於一九六三年出版，並於一九七二年提出「蝴蝶效應」的著名名詞。羅倫茲擁有達特茅斯學院、哈佛和麻省理工學院的學位，獲獎無數，一九九一年獲頒「京都獎」時，主辦單位盛讚他的科學成就是「繼牛頓之後，人類觀察自然得到的最偉大發現。」混沌理論架構簡單，被廣泛運用在氣象及其他科學領域。他的友人和門生形容羅倫茲是個「安靜的怪傑」、「所見過最有組織的人」，他的同事也說羅倫茲惜字如金，讓他開口說話難如登天，但也稱讚他是個親切且謙虛的人。 ───────────────────────────────────── Edward N. Lorenz, a Meteorologist and a Father of Chaos Theory, Dies at 90 < New York Times - By KENNETH CHANG > http://www.nytimes.com/2008/04/17/us/17lorenz.html Edward N. Lorenz, a meteorologist who tried to predict the weather with computers but instead gave rise to the modern field of chaos theory, died Wednesday at his home in Cambridge, Mass. He was 90. The cause was cancer, said his daughter Cheryl Lorenz. In discovering “deterministic chaos,” Dr. Lorenz established a principle that “profoundly influenced a wide range of basic sciences and brought about one of the most dramatic changes in mankind’s view of nature since Sir Isaac Newton,” said a committee that awarded him the 1991 Kyoto Prize for basic sciences. Dr. Lorenz is best known for the notion of the “butterfly effect,” the idea that a small disturbance like the flapping of a butterfly’s wings can induce enormous consequences. As recounted in the book “Chaos” by James Gleick, Dr. Lorenz’s accidental discovery of chaos came in the winter of 1961. Dr. Lorenz was running simulations of weather using a simple computer model. One day, he wanted to repeat one of the simulations for a longer time, but instead of repeating the whole simulation, he started the second run in the middle, typing in numbers from the first run for the initial conditions. The computer program was the same, so the weather patterns of the second run should have exactly followed those of the first. Instead, the two weather trajectories quickly diverged on completely separate paths. At first, he thought the computer was malfunctioning. Then he realized that he had not entered the initial conditions exactly. The computer stored numbers to an accuracy of six decimal places, like 0.506127, while, to save space, the printout of results shortened the numbers to three decimal places, 0.506. When typing in the new conditions, Dr. Lorenz had entered the rounded-off numbers, and even this small discrepancy, of less than 0.1 percent, completely changed the end result. Even though his model was vastly simplified, Dr. Lorenz realized that this meant perfect weather prediction was a fantasy. A perfect forecast would require not only a perfect model, but also perfect knowledge of wind, temperature, humidity and other conditions everywhere around the world at one moment of time. Even a small discrepancy could lead to completely different weather. Dr. Lorenz published his findings in 1963. “The paper he wrote in 1963 is a masterpiece of clarity of exposition about why weather is unpredictable,” said J. Doyne Farmer, a professor at the Santa Fe Institute in New Mexico. The following year, Dr. Lorenz published another paper that described how a small twiddling of parameters in a model could produce vastly different behavior, transforming regular, periodic events into a seemingly random chaotic pattern. At a meeting of the American Association for the Advancement of Science in 1972, he gave a talk with a title that captured the essence of his ideas: “Predictability: Does the Flap of a Butterfly’s Wings in Brazil Set Off a Tornado in Texas?” Dr. Lorenz was not the first to stumble onto chaos. At the end of the 19th century, the mathematician Henri Poincaré showed that the gravitational dance of as few as three heavenly bodies was hopelessly complex to calculate, even though the underlying equations of motion seemed simple. But Poincar's findings were forgotten through the first three-quarters of the 20th century. Dr. Lorenz’s papers also attracted little notice until the mid-1970s. “When it finally penetrated the community, that was what started people to really start to pay attention to this and led to tremendous development,” said Edward Ott, a professor of physics and electrical engineering at the University of Maryland. “He demonstrated a chaotic model in a real situation.” Born in 1917 in West Hartford, Conn., Edward Norton Lorenz received a bachelor's degree in mathematics from Dartmouth College in 1938 and a master's degree in math from Harvard in 1940. He worked as a weather forecaster during World War II, leading him to pursue graduate studies in meteorology; he earned master's and doctoral degrees in meteorology from the Massachusetts Institute of Technology in 1943 and 1948. Dr. Lorenz was a staff member of M.I.T.’s meteorology department from 1948 to 1955, when he became an assistant professor. He was promoted to professor in 1962 and served as head of the department from 1977 to 1981. He became an emeritus professor in 1987. In addition to his daughter Cheryl, of Eugene, Ore., Dr. Lorenz is survived by another daughter, Nancy Lorenz of Roslindale, Mass; a son, Edward H. Lorenz of Grasse, France; and four grandchildren. His wife, Jane, died in 2001. Dr. Lorenz remained active almost to the end of his life, in both research and outdoor activities. “He was out hiking two and one-half weeks ago,” Cheryl Lorenz said, “and he finished a paper a week ago with a colleague.” ───────────────────────────────────── 混沌理論之父「羅倫茲」過世享年90歲 < 中廣新聞／葉柏毅 > http://news.chinatimes.com/2007Cti/2007Cti-News/2007Cti-News-Content/ 0,4521,130504+132008041701191,00.html 提出「混沌理論」的美國麻省理工學院教授「愛德華．羅倫茲」，星期三在他位於麻州劍橋的家中過世，享年九十歲。羅倫茲是美國著名的氣象學家，他所提出的「混沌理論」，簡單來說，就是「小小的作用，會引發巨大的變化」，因為羅倫茲曾經舉例說，所謂的混沌理論，就像是在巴西的蝴蝶拍拍翅膀，會對周圍的大氣系統，產生一些作用，而這些作用會不斷地被放大，最後可能會引發美國德州的龍捲風，因此也有人把「混沌理論」叫做「蝴蝶效應」。羅倫茲得過無數的科學獎項，也有人說，他所提出的「混沌理論」，是繼牛頓之後，給人類帶來對自然界最有創意的新觀點。 -- 夫兵者不祥之器物或惡之故有道者不處君子居則貴左用兵則貴右兵者不祥之器非君子之器不得已而用之恬淡為上勝而不美而美之者是樂殺人夫樂殺人者則不可得志於天下矣吉事尚左凶事尚右偏將軍居左上將軍居右言以喪禮處之殺人之眾以哀悲泣之戰勝以喪禮處之道常無名樸雖小天下莫能臣侯王若能守之萬物將自賓天地相合以降甘露民莫之令而自均始制有名名亦既有夫亦將知止知止可以不殆譬道之在天140.122.144.48海

推

dreamkid

04/18 21:52, , 1^F

04/18 21:52, 1^F

推

IYOUHESHE

04/18 22:56, , 2^F

04/18 22:56, 2^F

推

Vccv

04/18 23:48, , 3^F

04/18 23:48, 3^F