Media systems (especially broadcasting) can be classified in two different types:
Public Media Systems: Government control over broadcasting through ownership, regulation, and partial funding of public broadcasting services.
Private Media System: Ownership and control lies in the hands of private companies and shareholders.
Both systems can exist in various forms, according to the degree of control by governments and private companies, with mixed systems (public and private) as the third main kind.
Whereas public media systems are usually at least partially funded by governments, private broadcasting solely relies on advertising revenue. Still also public media systems cannot exclude advertising as a source of revenue. Therefore both types are to a certain degree dependent on money coming in by advertisers.
And this implies consequences on the content provided by the media. As the attraction of advertisers becomes critically important, interests of the advertising industry frequently play a dominant role concerning the structure of content and the creation of environments favorable for advertising goods and services within the media becomes more and more common.
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1913 the wheel cipher gets re-invented as a strip
1917
- an AT&T-employee, Gilbert S. Vernam, invents a polyalphabetic cipher machine that works with random-keys
1918 the Germans start using the ADFGVX-system, that later gets later by the French Georges Painvin
- Arthur Scherbius patents a ciphering machine and tries to sell it to the German Military, but is rejected
1919 Hugo Alexander Koch invents a rotor cipher machine
1921 the Hebern Electric Code, a company producing electro-mechanical cipher machines, is founded
1923 Arthur Scherbius founds an enterprise to construct and finally sell his
late 1920's/30's more and more it is criminals who use cryptology for their purposes (e.g. for smuggling). Elizabeth Smith Friedman deciphers the codes of rum-smugglers during prohibition regularly
1929 Lester S. Hill publishes his book Cryptography in an Algebraic Alphabet, which contains enciphered parts
1933-1945 the Germans make the Enigma machine its cryptographic main-tool, which is broken by the Poles Marian Rejewski, Gordon Welchman and Alan Turing's team at Bletchley Park in England in 1939
1937 the Japanese invent their so called Purple machine with the help of Herbert O. Yardley. The machine works with telephone stepping relays. It is broken by a team of
1930's the Sigaba machine is invented in the USA, either by W.F. Friedman or his colleague Frank Rowlett
- at the same time the British develop the Typex machine, similar to the German Enigma machine
1943 Colossus, a code breaking computer is put into action at Bletchley Park
1943-1980 the cryptographic Venona Project, done by the NSA, is taking place for a longer period than any other program of that type
1948 Shannon, one of the first modern cryptographers bringing mathematics into cryptography, publishes his book A Communications Theory of Secrecy Systems
1960's the Communications-Electronics Security Group (= CESG) is founded as a section of Government Communications Headquarters (= GCHQ)
late 1960's the IBM Watson Research Lab develops the Lucifer cipher
1969 James Ellis develops a system of separate public-keys and private-keys
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Artificial Intelligence is concerned with the simulation of human thinking and emotions in information technology. AI develops "intelligent systems" capable, for example, of learning and logical deduction. AI systems are used for creatively handling large amounts of data (as in data mining), as well as in natural speech processing and image recognition. AI is also used as to support
Yahoo AI sites:
MIT AI lab:
The MIT (Massachusetts Institute of Technology) is a privately controlled coeducational institution of higher learning famous for its scientific and technological training and research. It was chartered by the state of Massachusetts in 1861 and became a land-grant college in 1863. During the 1930s and 1940s the institute evolved from a well-regarded technical school into an internationally known center for scientific and technical research. In the days of the Great Depression, its faculty established prominent research centers in a number of fields, most notably analog computing (led by
The U.S. Data Encryption Standard (= DES) is the most widely used encryption algorithm, especially used for protection of financial transactions. It was developed by IBM in 1971. It is a symmetric-key cryptosystem. The DES algorithm uses a 56-bit encryption key, meaning that there are 72,057,594,037,927,936 possible keys.
for more information see: