<nettime> R.I.P. Claude E. Shannon

[Janos Sugar <sj@c3.hu>]

--------------------

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 Œbit,ı today used to
describe individual units of information processed by a computer, was
coined from Shannonıs 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, MITıs 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 childıs
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 Bushıs
suggestion, Shannon also studied the operation of the analyzerıs relay
circuits for his masterıs thesis. This analysis formed the basis for
Shannonıs 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.

Shannonıs 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.

Booleıs 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 Œyesı and Œnoı
statements to Œandı, Œorı or Œnotı operations.

Shannon graduated from MIT in 1940 with both a masterıs 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, Shannonıs 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 Œbit,ı
comprised of the first two and the last letter of Œbinary digitı 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.

Shannonıs 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
Shannonıs. 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 İ 1994-99 Jones International and Jones Digital Century. All
rights reserved.


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