Janos Sugar on 3 Mar 2001 18:08:33 -0000 |
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<nettime> R.I.P. Claude E. Shannon |
-------------------- Claude Elwood Shannon Noted as a founder of information theory, Claude Shannon combined mathematical theories with engineering principles to set the stage for the development of the digital computer. The term �bit,� today used to describe individual units of information processed by a computer, was coined from Shannon�s research in the 1940s. A Midwesterner, Claude Shannon was born in Gaylord, Michigan in 1916. From an early age, he showed an affinity for both engineering and mathematics, and graduated from Michigan University with degrees in both disciplines. For his advanced degrees, he chose to attend the Massachusetts Institute of Technology. At the time, MIT was one of a number of prestigious institutions conducting research that would eventually formulate the basis for what is now known as the information sciences. Its faculty included mathematician Norbert Wiener, who would later coin the term cybernetics to describe the work in information theories that he, Shannon and other leading American mathematicians were conducting; and Vannevar Bush, MIT�s dean of engineering, who in the early 1930s had built an analog computer called the Differential Analyzer The Differential Analyzer was developed to calculate complex equations that tabulators and calculators of the day were unable to address. It was a mechanical computer, using a series of gears and shafts to engage cogs until the equation was solved. Once it completed its cycle, the answer to the equation was obtained by measuring the changes in position of its various machine parts. Its only electrical parts were the motors used to drive the gears. With its crude rods, gears and axles, the analyzer looked like a child�s erector set. Setting it up to work one equation could take two to three days; solving the same equation could take equally as long, if not longer. In order to work a new problem, the entire machine, which took up several hundred feet of floor space, had to be torn apart and reset to a new mechanical configuration. While at MIT, Shannon studied with both Wiener and Bush. Noted as a "tinkerer", he was ideally suited to working on the Differential Analyzer, and would set it up to run equations for other scientists. At Bush�s suggestion, Shannon also studied the operation of the analyzer�s relay circuits for his master�s thesis. This analysis formed the basis for Shannon�s influential 1938 paper "A Symbolic Analysis of Relay and Switching Circuits," in which he put forth his developing theories on the relationship of symbolic logic to relay circuits. This paper, and the theories it contained, would have a seminal impact on the development of information processing machines and systems in the years to come. Shannon�s paper provided a glimpse into the future of information processing. While studying the relay switches on the Differential Equalizer as they went about formulating an equation, Shannon noted that the switches were always either open or closed, or on and off. This led him to think about a mathematical way to describe the open and closed states, and he recalled the logical theories of mathematician George Boole, who in the middle 1800s advanced what he called the logic of thought, in which all equations were reduced to a binary system consisting of zeros and ones. Boole�s theory, which formulated the basis for Boolean algebra, stated that a statement of logic carried a one if true and a zero if false. Shannon theorized that a switch in the on position would equate to a Boolean one. In the off position, it was a zero. By reducing information to a series of ones and zeros, Shannon wrote, information could be processed by using on-off switches. He also suggested that these switches could be connected in such a way to allow them to perform more complex equations that would go beyond simple �yes� and �no� statements to �and�, �or� or �not� operations. Shannon graduated from MIT in 1940 with both a master�s degree and doctorate in mathematics. After graduation, he spent a year as a National Research Fellow at the Institute for Advanced Study at Princeton University, where he worked with mathematician and physicist Hermann Weyl. In 1941, Shannon joined the Bell Telephone Laboratories, where he became a member of a group of scientists charged with the tasks of developing more efficient information transmitting methods and improving the reliability of long-distance telephone and telegraph lines. Shannon believed that information was no different than any other quantity and therefore could be manipulated by a machine. He applied his earlier research to the problem at hand, again using Boolean logic to develop a model that reduced information to its most simple form--a binary system of yes/no choices, which could be presented by a 1/0 binary code. By applying set codes to information as it was transmitted, the noise it picked up during transmission could be minimized, thereby improving the quality of information transmission. In the late 1940s, Shannon�s research was presented in The Mathematical Theory of Communications, which he co-authored with mathematician Warren Weaver. It was in this work that Shannon first introduced the word �bit,� comprised of the first two and the last letter of �binary digit� and coined by his colleague John W. Turley, to describe the yes-no decision that lay at the core of his theories. In the 1950s, Shannon turned his efforts to developing what was then called "intelligent machines,"�mechanisms that emulated the operations of the human mind to solve problems. Of his inventions during that time, the best known was a maze-solving mouse called Theseus, which used magnetic relays to learn how to maneuver through a metal maze. Shannon�s information theories eventually saw application in a number of disciplines in which language is a factor, including linguistics, phonetics, psychology and cryptography, which was an early love of Shannon�s. His theories also became a cornerstone of the developing field of artificial intelligence, and in 1956 he was instrumental in convening a conference at Dartmouth College that was the first major effort in organizing artificial intelligence research. Copyright � 1994-99 Jones International and Jones Digital Century. 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