Threshold

From Freepedia

In general, a threshold is a fixed location or value where an abrupt change is observed. It may also have the following meanings:

• In architecture, a threshold is a strip of wood, metal or stone located on the floor in a doorway following the line of division between the two spaces linked by the doorway.

• In aviation, a threshold is the end of a runway over which an airplane first passes when landing.

• In Biology, an action potential is initiated if the membrane potential is depolarized to the threshold potential. See: Action potential.

• In telecommunication, the term threshold has the following meanings:
  1. The minimum value of a signal that can be detected by the system or sensor under consideration.
  2. A value used to denote predetermined levels, such as those pertaining to volume of message storage, i.e., in-transit storage or queue storage, used in a message switching center.
  3. The minimum value of the parameter used to activate a device.
  4. The minimum value a stimulus may have to create a desired effect.
  • Source: from Federal Standard 1037C and from MIL-STD-188

• In electrical engineering and machine learning, a threshold circuit or unit is a one-input, one-output device or object that implements a Heaviside step function; the threshold value corresponds to the transition in this function between one and zero.

• In elections, threshold refers to the minimal amount of votes necessary to win representation.

• In psychology, sensory threshold is one of the nine aspects of temperment. The minimum amount of stimulus energy necessary to elicit a sensory response.

• Threshold is the name of a science-fiction book by David R. Palmer.

• Name of progressive metal band Threshold from England.

• In occupational safety and health, see ACGI and its Threshold Limit Values (TLV).

• In the video game "Halo", Threshold is the planet around which the ringworld Halo orbits. It is presumably a gas giant, as there is a level in Halo 2 set in a research facility which is suspended in the atmosphere of Threshold and falls a great distance into the atmosphere later in that mission without ever hitting land. Threshold has one known natural satellite, a moon named Basis.

• The Sci Fi Channel aired a movie in 2003 entitled Threshold. [1]

• Threshold is also the name of a science-fiction television series that began airing in 2005 on CBS.

• Threshold was an episode in Star Trek: Voyager.

The word "threshold is derived from O.E. þrescold, þærscwold, þerxold "doorsill, point of entering," first element related to O.E. þrescan (see thresh), with its original sense of "tread, trample." Second element of unknown origin and much transformed in all the Gmc. languages; in Eng. it probably has been altered to conform to hold, but the oft-repeated story that the threshold was a barrier placed at the doorway to hold the chaff flooring in the room is mere folk etymology. Cognates include O.N. þreskjoldr, Swed. tröskel, O.H.G. driscufli, Ger. dial. drischaufel.