Entropy (arrow of time) — Entropy is the only quantity in the physical sciences that picks a particular direction for time, sometimes called an arrow of time. As one goes forward in time, the second law of thermodynamics says that the entropy of an isolated system can… … Wikipedia
Constant bitrate — (CBR) is a term used in telecommunications, relating to the quality of service. Compare with variable bitrate. When referring to codecs, constant bit rate encoding means that the rate at which a codec s output data should be consumed is constant … Wikipedia
Entropy — En tro*py, n. [Gr. ? a turning in; ? in + ? a turn, fr. ? to turn.] (Thermodynamics) A certain property of a body, expressed as a measurable quantity, such that when there is no communication of heat the quantity remains constant, but when heat… … The Collaborative International Dictionary of English
Entropy — This article is about entropy in thermodynamics. For entropy in information theory, see Entropy (information theory). For a comparison of entropy in information theory with entropy in thermodynamics, see Entropy in thermodynamics and information… … Wikipedia
Entropy (classical thermodynamics) — In thermodynamics, entropy is a measure of how close a thermodynamic system is to equilibrium. A thermodynamic system is any physical object or region of space that can be described by its thermodynamic quantities such as temperature, pressure,… … Wikipedia
Entropy (statistical thermodynamics) — In thermodynamics, statistical entropy is the modeling of the energetic function entropy using probability theory. The statistical entropy perspective was introduced in 1870 with the work of the Austrian physicist Ludwig Boltzmann. Mathematical… … Wikipedia
Entropy of mixing — The entropy of mixing is the change in the configuration entropy, an extensive thermodynamic quantity, when two different chemical substances or components are mixed. This entropy change must be positive since there is more uncertainty about the… … Wikipedia
Entropy (information theory) — In information theory, entropy is a measure of the uncertainty associated with a random variable. The term by itself in this context usually refers to the Shannon entropy, which quantifies, in the sense of an expected value, the information… … Wikipedia
Entropy in thermodynamics and information theory — There are close parallels between the mathematical expressions for the thermodynamic entropy, usually denoted by S , of a physical system in the statistical thermodynamics established by Ludwig Boltzmann and J. Willard Gibbs in the 1870s; and the … Wikipedia
Entropy (ecology) — Ecological entropy is a measure of biodiversity in the study of biological ecology.DefinitionAssume that within a system of unlimited individuals, there exists n species of organisms (A 1, A 2, ..., A j, ..., A n), and the probability that an… … Wikipedia