Claude Elwood Shannon
Claude Elwood Shannon (
April 30,
1916 –
February 24,
2001), an
American electrical engineer and
mathematician, has been called "the father of
information theory", and was the founder of practical
digital circuit design theory.
Shannon was born in
Petoskey, Michigan. The first sixteen years of Shannon's life were spent in
Gaylord, Michigan, where he attended the Public School, graduating from
Gaylord High School in 1932. While growing up, he worked as a messenger for
Western Union. Shannon was a distant relative of
Thomas Edison.
Boolean theory
In
1932 he entered the
University of Michigan, where he took a course that introduced him to the works of
George Boole. He graduated in
1936 with two
bachelor's degrees, one in
electrical engineering and one in
mathematics, then began graduate study at the
Massachusetts Institute of Technology, where he worked on
Vannevar Bush's
differential analyzer, an
analog computer.
While studying the complicated ad hoc circuits of the differential analyzer, Shannon saw that Boole's concepts could be used to great utility. A paper drawn from his
1937 master's
thesis,
A Symbolic Analysis of Relay and Switching Circuits, was published in the
1938 issue of the
Transactions of the American Institute of Electrical Engineers. It also earned Shannon the
Alfred Noble American Institute of American Engineers Award in
1940.
Howard Gardner, of
Harvard University, called Shannon's thesis "possibly the most important, and also the most famous, master's thesis of the century".
In this work, Shannon proved that
Boolean algebra and
binary arithmetic could be used to simplify the arrangement of the electromechanical
relays then used in telephone routing switches, then turned the concept upside down and also proved that it should be possible to use arrangements of relays to solve Boolean algebra problems. Exploiting this property of electrical switches to do logic is the basic concept that underlies all electronic digital computers. Shannon's work became the foundation of practical
digital circuit design when it became widely known among the electrical engineering community during and after
World War II. The theoretical rigor Shannon's work supplied completely replaced the "ad hoc" methods that had prevailed heretofore.
Flush with this success, Vannevar Bush suggested that Shannon work on his dissertation at
Cold Spring Harbor Laboratory, funded by the Carnegie Institution headed by Bush, to develop similar mathematical relationships for
Mendelian genetics, which resulted in Shannon's
1940 PhD thesis at MIT,
An Algebra for Theoretical Genetics.Wartime research
Shannon then joined
Bell Labs to work on fire-control systems and cryptography during World War II, under a contract with section D-2 (Control Systems section) of the National Defense Research Committee (
NDRC).
In 1945, as the war was coming to an end, the NDRC was issuing a summary of technical reports as a last step prior to its eventual closing down. Inside the volume on Fire Control a special essay titled
Data Smoothing and Prediction in Fire-Control Systems, coauthored by Richard B. Blackman,
Hendrik Wade Bode, and Claude Shannon, formally introduced the problem of Fire Control as a special case of
transmission, manipulation and utilization of intelligence, in other words it modeled the problem in terms of
Data and
Signal Processing and thus heralded the coming of the
information age. Shannon was greatly influenced by this work. It is clear that the
technological convergence of the information age was preceded by the
synergy between these scientific minds and their collaborators.
Postwar contributions
In
1948 Shannon published
A Mathematical Theory of Communication article in two parts in the July and October issues of the
Bell System Technical Journal. This work focuses on the problem of how to best encode the
information a sender wants to transmit. In this fundamental work he used tools in probability theory, developed by
Norbert Wiener, which were in their nascent stages of being applied to communication theory at that time. Shannon developed
information entropy as a measure for the uncertainty in a message while essentially inventing what became known as the dominant form of "information theory." The book, co-authored with
Warren Weaver,
The Mathematical Theory of Communication, reprints Shannon's 1948 article and Weaver's popularization of it, which is accessible to the non-specialist. Shannon's concepts were also popularized, subject to his own proofreading, in
John Robinson Pierce's
Symbols, Signals, and Noise.
Another notable paper published in
1949 is
Communication Theory of Secrecy Systems, a major contribution to the development of a mathematical theory of
cryptography. He is also credited with the introduction of
Sampling Theory, which is concerned with representing a continuous-time signal from a (uniform) discrete set of samples.
He returned to MIT to hold an endowed chair in 1956.
Hobbies and Inventions
Outside of his academic pursuits, Shannon was interested in
juggling,
unicycling, and
chess. He also invented many devices, including rocket-powered
Frisbees, a motorized pogo stick, a wearable computer to predict the result of playing
roulette [
1], and a flame-throwing trumpet for a science exhibition. One of his more humorous devices was a box he kept on his desk with a single switch on the side. When the switch was flipped, the lid of the box opened and a mechanical hand reached out, flipped off the switch, then retracted back inside the box.
Legacy and Tributes
Shannon came to the
Massachusetts Institute of Technology (
MIT) in
1956 to join its faculty and to conduct work in the
Research Laboratory of Electronics (RLE). He continued to serve on the
MIT faculty until
1978. To commemorate his achievements, there were celebrations of his work in 2001, and there are currently five statues of Shannon: one at the
University of Michigan; one at
MIT in the
Laboratory for Information and Decision Systems; one in
Gaylord, Michigan; one at the University of California at San Diego; and another at Bell Labs. After the breakup of the Bell system, the part of Bell Labs that remained with
AT&T was named Shannon Labs in his honor.
Robert Gallager has called Shannon the greatest scientist of the
20th century. According to
Neil Sloane, an AT&T fellow who co-edited Shannon's large collection of papers in 1993, the perspective introduced by Shannon's
communication theory (now called
information theory) is the foundation of the digital revolution and every device containing a
microprocessor or
microcontroller is a conceptual descendant of Shannon's 1948 publication.
[ C. E. Shannon: A mathematical theory of communication. Bell System Technical Journal, vol. 27, pp. 379–423 and 623–656, July and October, 1948] "He's one of the great men of the
century. Without him, none of the things we know today would exist. The whole
digital revolution started with him," said Neil Sloane, according to a
Star-Ledger obituary article.
[ Bell Labs digital guru dead at 84 Pioneer scientist led high-tech revolution (The Star-Ledger, obituary by Kevin Coughlin 27 February, 2001)]Shannon's computer chess program
In 1950 Shannon published a groundbreaking paper on
computer chess entitled
Programming a Computer for Playing Chess. It describes how a machine or computer could be made to play a reasonable game of
chess. His process for having the computer decide on which move to make is a
minimax procedure, based on an
evaluation function of a given chess position. Shannon gave a rough example of an evaluation function in which the value of the black position was subtracted from that of the white position.
Material was counted according to the usual relative
chess piece point value (1 point for a pawn, 3 points for a knight or bishop, 5 points for a rook, and 9 points for a queen). He considered some positional factors, subtracting ½ point for each
doubled pawn,
backward pawn, and
isolated pawn. Another positional factor in the evaluation function was
mobility, adding 0.1 point for each legal move available. Finally, he considered
checkmate to be the capture of the king, and gave it the artificial value of 200 points. Quoting from the paper:
The coefficients .5 and .1 are merely the writer's rough estimate. Furthermore, there are many other terms that should be included. The formula is given only for illustrative purposes. Checkmate has been artificially included here by giving the king the large value 200 (anything greater than the maximum of all other terms would do).The evaluation function is clearly for illustrative purposes, as Shannon stated. For example, according to the function, pawns that are doubled as well as isolated would have no value at all, which is clearly unrealistic.
The reason for assigning checkmate a value higher than the maximum sum of all other terms is so that the minimax procedure will value checkmate above all else and thus it will sacrifice as much material as it has to in order to prevent itself from being checkmated, or to checkmate the opponent. The value is arbitrary â€" any number larger than the sum of all of the other terms would cause the minimax procedure to give the same result.
The Las Vegas connection: Information theory and its applications to game theory
Shannon and his wife Betty also used to go on weekends to
Las Vegas with
M.I.T. mathematician
Ed Thorp,
[American Scientist online: Bettor Math, article and book review by Elwyn Berlekamp] and made very successful forays in
roulette and
blackjack using
game theory type methods co-developed with fellow Bell Labs associate, Texas tough guy, recreational
gunslinger,
daredevil pilot and physicist
John L. Kelly Jr. based on principles of information theory,
[John Kelly by William Poundstone website] making a fortune as detailed in the book
Fortune's Formula by William Poundstone and corroborated by the writings of Elwyn Berlecamp,
[Elwyn Berlekamp (Kelly's Research Assistant) Bio details] Kelly's research assistant in 1960 and 1962.
[Poundstone, William: Fortune's Formula : The Untold Story of the Scientific Betting System That Beat the Casinos and Wall Street] Shannon and Thorp also applied the same theory, later known as the
Kelly criterion, to the stock market with even better results.
[William Pounstone website]Other trivia
He met his wife Betty when she was a numerical analyst at
Bell Labs.
*
Alfred Noble Prize, 1940
*
Morris Liebmann Memorial Award of the
Institute of Radio Engineers, 1949
*
Yale University (Master of Science), 1954
*
Stuart Ballantine Medal of the
Franklin Institute, 1955
*
Research Corporation Award, 1956
*
University of Michigan, honorary doctorate, 1961
*
Rice University Medal of Honor, 1962
*
Princeton University, honorary doctorate, 1962
*
Marvin J. Kelly Award, 1962
*
University of Edinburgh, honorary doctorate, 1964
*
University of Pittsburgh, honorary doctorate, 1964
*
Institute of Electrical and Electronics Engineers Medal of Honor, 1966
*
National Medal of Science, 1966, presented by President
Lyndon B. Johnson*Golden Plate Award, 1967
*
Northwestern University, honorary doctorate, 1970
*
Harvey Prize, the
Technion of
Haifa,
Israel, 1972
*
Royal Netherlands Academy of Arts and Sciences (KNAW), foreign member, 1975
*
University of Oxford, honorary doctorate, 1978
*
Joseph Jacquard Award, 1978
*
Harold Pender Award, 1978
*
University of East Anglia, honorary doctorate, 1982
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Carnegie Mellon University, honorary doctorate, 1984
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Audio Engineering Society Gold Medal, 1985
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Kyoto Prize, 1985
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Tufts University, honorary doctorate, 1987
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University of Pennsylvania, honorary doctorate, 1991
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Eduard Rhein Prize, 1991
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National Inventors Hall of Fame inducted, 2004
*
Shannon-Fano coding*
Shannon-Hartley law*
Nyquist-Shannon sampling theorem*
Shannon's theorem*
Rate distortion theory*
Information theory*
Confusion and diffusion*
One-time pad*
Shannon switching game*
Shannon number*
Claude E. Shannon Award*
Shannon indexCited references
General references
* Claude E. Shannon:
A Mathematical Theory of Communication, Bell System Technical Journal, Vol. 27, pp. 379–423, 623–656, 1948.
* Claude E. Shannon and Warren Weaver:
The Mathematical Theory of Communication. The University of Illinois Press, Urbana, Illinois, 1949. ISBN 0252725484
* Claude E. Shannon:
Programming a Computer for Playing Chess, Philosophical Magazine, Ser.7, Vol. 41, No. 314, March 1950. (Available online under
External links below)
* David Levy:
Computer Gamesmanship: Elements of Intelligent Game Design, Simon & Schuster, 1983. ISBN 0-671-49532-1
*Mindell, David A., "Automation's Finest Hour: Bell Labs and Automatic Control in World War II",
IEEE Control Systems, December 1995, pp. 72-80.
*David Mindell, Jérôme Segal, Slava Gerovitch, "From Communications Engineering to Communications Science: Cybernetics and Information Theory in the United States, France, and the Soviet Union"
Science and Ideology: A Comparative History, Mark Walker (Ed.), Routledge, London, 2003, pp. 66-95.
*
A Mathematical Theory of Communication*
Communication Theory of Secrecy Systems*
Communication in the Presence of Noise*
Summary of Shannon's life and career*
Biographical summary from Shannon's collected papers*
Video documentary: "Claude Shannon - Father of the Information Age"*
Mathematical Theory of Claude Shannon In-depth MIT class paper on the development of Shannon's work to 1948.
*
Obituary at MIT*
Obituary Royal Netherlands Academy of Sciences (in Dutch)*
Retrospective at the University of Michigan*
Shannon's Michigan Profile*
Notes on Computer-Generated Text*
Shannonizer An example of his work*
Shannon's Juggling Theorem and Juggling Robots*
Shannon's paper on computer chess, text*
Shannon's paper on computer chess (
PDF)
*
Shannon's paper on computer chess, text, alternate source*
Photos
