Fr.: entropie de l'information
The measure of information, which is usually expressed by the average number of bits needed for storage or communication. In other words, the degree to which the values of a → random variable X are dispersed. If the → probability density function of X is P(x), the entropy is defined by: H(X) = -Σ P(x) log P(x). Also called → Shannon entropy.
Fr.: flot d'information
The flow of data into a system or to the end users.
Fr.: paradoxe de l'information
A paradox raised in 1976 by S. Hawking (1942-) whose analysis of the thermodynamic properties of → black holes led him to the prediction that black holes are not in fact black, but radiate due to quantum effects. This implied that, due to the → Hawking radiation, a black hole would eventually evaporate away, leaving nothing. This deduction presented a problem for quantum mechanics, which maintains that nothing, including information, can ever be lost. A solution is that black holes radiate away a category of information through the Hawking radiation and at the same time they destroy all of another category of information, in compatibility with the → second law of thermodynamics.
dâneš-e azdâyeš azdâyik (#)
Same as → informatics.
Fr.: technologie de l'informtion
The science and activity of receiving, storing, processing, and transmitting information by using → computers.
negare-ye azdâyeš (#)
Fr.: théorie de l'information
The mathematical theory that defines, quantifies,
and analyzes the concept of → information.
It involves → probability theory in
→ transmission of → messages
when the → bits of information are subject to various
distortions. Its goal is to enable as much information as possible to be reliably
stored on a medium, retrieved, or communicated.
A person who provides → information.
The global network of all the world's communications, databases, and sources of information.
From L. infra "below, underneath, beneath," from PIE *ndher; cf. Mod.Pers. zir "below, down," akin to → under-.
Foru-, from foru "down, downward; below; under, beneath; low," from Mid.Pers. frôt "down, downward;" O.Pers. fravata "forward, downward;" cf. Skt. pravát- "a sloping path, the slope of a mountain."
The invisible part of electromagnetic spectrum possessing wavelengths between those of visible light and those of radio waves, i.e. approximately between about 0.75 and 1000 μm.
From L. infra (adv., prep.) "below, underneath, beneath," inferus "lower," from PIE *ndher; cf. Av. aδara- (adj.), aδairi- (prep.) "below;" Mid.Pers. êr "below, down; low, under," adar "low," azêr "below, under" (Mod.Pers. zir "below, down"); Skt. ádhara- "lower;" O.E. under "under, among"); → red.
Forusorx, from foru "down, downward; below; beneath;" Mid.Pers. frôt "down, downward;" O.Pers. fravata "forward, downward;" cf. Skt. pravát- "a sloping path, the slope of a mountain," + sorx→ red.
Fr.: détecteur mosaïque infrarouge
A two-dimensional infrared imaging device, consisting of an array of small, individual electronic detectors, each of which records a pixel in the image.
Infrared Astronomical Satellite (IRAS)
mâhvâre-ye axtaršenâxti-e forusorx (#)
Fr.: satellite astronomique infrarouge
An orbiting infrared telescope (60 cm mirror) which successfully operated from launch in January 1983 until the supply of coolant ran out in November 1983. It was a collaborative mission between NASA, the Netherlands, and the UK, and mapped 95% of the whole sky in the wavelength bands 12, 25, 60, and 100 microns.
axtaršenâsi-ye forusorx (#)
Fr.: astronomie infrarouge
The study of infrared properties of astronomical objects.
Fr.: caméra infrarouge
sirus-e forusorx (#)
Fr.: cirrus infrarouge
Wispy, extended structures seen above and below the plane of the Galaxy in the infrared maps of the sky (60-100 microns) produced by the → Infrared Astronomical Satellite (IRAS).
→ infrared; L. cirrus "curl, tuft, plant filament like a tuft of hair."
infrared dark cloud (IRDC)
abr-e târik-e forusorx
Fr.: nuage sombre infrarouge
A → dark cloud characterized by a → visual extinction Av≥ 102 mag. IRDCs are opaque even at 8 μm, and can be seen in silhouette against the bright diffuse → mid-infrared emission in the → interstellar medium.
âškârgar-e forusorx (#)
Fr.: détecteur infrarouge
A thermal device for observing and measuring → infrared radiation.
Fr.: émission infrarouge
fozuni-ye forusorx, ferehbud-e ~
Fr.: excès infrarouge