Topic: entropy

topics > computer science > Group: information

digital communication

chaotic behavior
statistical mechanics


Entropy measures the randomness of a system and its components. For example, the entropy of a gas at uniform temperature is higher than if one area is hotter than another. Entropy increases naturally. Information decreases as entropy increases. (cbb 11/07)
Subtopic: entropy as statistical up

Quote: Boltzmann made entropy a statistical property of an enormous number of particles; so disorder is only probably even though it is nearly certain [»campJ_1982]
Quote: a system in maximum entropy is constant at the surface but also changing constantly [»campJ_1982]

Subtopic: entropy increases up

Quote: the un-structuredness of a system (its entropy) increases with time unless work to reduce it [»belaLA3_1976]
Quote: random perturbations from the rest of the universe dissipates microscopic information; ensures the growth of thermodynamic entropy [»layzD12_1975]
Quote: despite lots of time spending tidying things, things get in a muddle by themselves [»bateG_1972]
Quote: things become a muddle because there are more untidy ways than tidy ones
QuoteRef: bateG_1972 ;;18 "And it would be a sort of cheating if the child used glue to make the blocks stand up in a position from which they would otherwise fall
Quote: under entropy, macroscopic information is converted into microscopic information (i.e., the location of molecules) [»layzD12_1975]

Subtopic: information/communication as entropy up

Quote: entropy is the measure of information; the only continuous property that increases with more choices, and decomposition is a weighted sum [»shanCE7_1948]
Quote: fundamental theorem for a discrete channel with noise; if source entropy less than channel capacity, average frequency of error is arbitrarily small [»shanCE7_1948]
Quote: if the entropy of a source is not more than a channel's capacity then have arbitrarily reliable transmission [»weinGM_1979]

Subtopic: anti-entropy up

Quote: use anti-entropy as a backup for rumor mongering [»demeA8_1987]
Quote: when solar photons hit the earth, they change abruptly to heat; life smoothes out the discontinuity [»thomR_1975]

Subtopic: inflationary universe up

Quote: if the universe expanded more rapidly than the effect of physical processes; it could produce macroscopic information

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Updated barberCB 5/04
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