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If one considers the text of every book ever published as a sequence, with each symbol being the text of a complete book, and if there are N published books, and each book is only published once, the estimate of the probability of each book is 1/N, and the entropy (in bits) is −log 2 (1/N) = log 2 (N). As a practical code, this corresponds to ...
The bitting code is used in conjunction with a key's Depth and Spacing Number to completely determine all relevant information regarding the key's geometry. [1] Each number in the bitting code corresponds to a cut on the key blade. For example, a bitting code of 11111 with Depth and Spacing Number 46 specifies a Kwikset key with five shallow cuts.
where U is the unicity distance, H(k) is the entropy of the key space (e.g. 128 for 2 128 equiprobable keys, rather less if the key is a memorized pass-phrase). D is defined as the plaintext redundancy in bits per character. Now an alphabet of 32 characters can carry 5 bits of information per character (as 32 = 2 5).
Given a discrete-time stationary ergodic stochastic process on the probability space (,,), the asymptotic equipartition property is an assertion that, almost surely, (,, …,) where () or simply denotes the entropy rate of , which must exist for all discrete-time stationary processes including the ergodic ones.
More precisely, the source coding theorem states that for any source distribution, the expected code length satisfies [(())] [ (())], where is the number of symbols in a code word, is the coding function, is the number of symbols used to make output codes and is the probability of the source symbol. An entropy coding attempts to ...
Entropy: A New World View is a non-fiction book by Jeremy Rifkin and Ted Howard, with an Afterword by Nicholas Georgescu-Roegen. It was first published by Viking Press, New York in 1980 (ISBN 0-670-29717-8). A paperback edition was published by Bantam in 1981, in a paperback revised edition, by Bantam Books, in 1989 (ISBN 0-553-34717-9).
[2] Even though the idea of the edge of chaos is an abstract one, it has many applications in such fields as ecology, [3] business management, [4] psychology, [5] political science, and other domains of the social sciences. Physicists have shown that adaptation to the edge of chaos occurs in almost all systems with feedback. [6]
The distribution and physical security of codebooks presents a special difficulty in the use of codes compared to the secret information used in ciphers, the key, which is typically much shorter. The United States National Security Agency documents sometimes use codebook to refer to block ciphers ; compare their use of combiner-type algorithm ...