All articles starting with N
16,460 articles
Noise figure
Noise figure, or noise factor, measures how much a two-port device like an amplifier degrades a signal's signal-to-noise ratio; it was introduced by Harald Friis in 1944.
Noise injection (machine learning)
Noise injection is a machine learning regularization technique that deliberately adds random perturbations to a model's inputs, weights, gradients, or activations during training to reduce overfitting.
Noise kernel
The noise kernel is the symmetrized two-point correlation function of a quantum field's stress-energy tensor, serving as the stochastic source in the Einstein-Langevin equation of stochastic gravity.
Noise level estimation
Noise level estimation is a signal and image processing method that measures the strength of noise in data from noisy observations alone, without a clean reference.
Noise mapping
Noise mapping is an acoustical engineering method that models and visualizes environmental sound levels around roads, railways, airports, and industrial sites using calculation rather than measurement.
Noise measurement
Noise measurement is the quantitative determination of sound levels and human exposure to them, using sound level meters and dosimeters and reported as sound level, time-weighted average, and noise dose.
Noise music
Noise music: experimental genre foregrounding feedback, distortion, and non-musical sounds over melody; also called Japanoise in North America. Emerged as a genre in the 1980s via cassette culture, with roots in Russolo's 1913 Art of Noises and key scenes in Japan (Merzbow).
Noise pollution
Noise pollution, also known as sound pollution or community noise, is unwanted or harmful environmental sound, dominated by transportation, that is linked to cardiovascular disease and sleep disturbance.
Noise Protocol Framework
The Noise Protocol Framework is a framework for cryptographic protocols based on Diffie-Hellman key agreement, designed by Trevor Perrin and used by WhatsApp, WireGuard, and Lightning.
Noise reduction
Noise reduction, also known as noise removal, is the set of techniques for suppressing background noise in a signal, usually audio, to improve the signal-to-noise ratio and intelligibility.
Noise reduction coefficient
The noise reduction coefficient (NRC) is a single-number rating of how much sound a material absorbs, averaging four octave bands under the ASTM C423 test method.
Noise rock
Noise rock: abrasive rock genre treating distortion, feedback, and dissonance as primary material; grew from punk and New York no wave (1978–83) via Sonic Youth, Big Black, and Swans into 1990s alternative rock.
Noise schedule
A noise schedule in a diffusion model is the sequence of noise variances specifying how much Gaussian noise is added at each forward step, shaping training and sampling quality.
Noise schedules and preconditioning
A noise schedule controls how much signal and noise mix at each diffusion step, and preconditioning rescales the network's inputs, outputs, and loss for stable training.
Noise shaping (computation)
Noise shaping (computation), also known as stochastic rounding, randomly maps numbers to maintain zero-mean error, limiting accumulated error growth to the square root of $n$.
Noise spectroscopy
Noise spectroscopy is a measurement technique that characterizes materials and devices by analyzing their intrinsic electrical fluctuations, most commonly low-frequency resistance noise, to study charge-carrier dynamics and defects.
Noise uncertainty
Noise uncertainty is the gap between a receiver's estimated and actual noise power, which degrades cognitive radio spectrum sensing and imposes an SNR wall below which reliable detection fails.
Noise-cancelling headphones
Noise-canceling headphones, or ANC headphones, are headphones or earbuds that reduce ambient sound by playing an inverse-phase anti-noise signal, best at canceling steady low-frequency noise like airplane cabins.
Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy
Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) is an ultrasensitive laser absorption technique for detecting gas-phase molecules, combining frequency modulation spectroscopy with a high-finesse optical cavity.
Noise-induced hearing loss
Noise-induced hearing loss (NIHL) is permanent or temporary hearing loss from loud impulse sounds or repeated exposure above 85 dBA, damaging cochlear hair cells; preventable, common in workers and teens, with no cure.
Noise, vibration, and harshness
Noise, vibration, and harshness (NVH) is the engineering field that measures and modifies the noise and vibration characteristics of vehicles, where it is treated as a customer-facing quality attribute.
Noises Off
Noises Off is Michael Frayn's 1982 three-act backstage farce, first staged at the Lyric Theatre Hammersmith, in which a touring company's production of Nothing On collapses across three acts; Olivier Award winner, major Broadway revivals in 2001 and 2016.
Noisey (Vice)
Noisey is a music publication and video channel created by Vice Media in 2011, which grew into a YouTube channel, a Viceland TV show, and a Beats 1 radio show.
Noisia
Noisia is a Dutch electronic music trio from Groningen, one of drum and bass's defining acts, who ran the label Vision Recordings and disbanded in 2022 before reuniting.
Noisily Festival 2025
Noisily Festival 2025 was the planned twelfth edition of the independent electronic and psytrance festival, set for July 2025 at Barkestone Wood, Leicestershire, before its cancellation.
Noisy intermediate-scale quantum era
The noisy intermediate-scale quantum (NISQ) era is the current stage of quantum computing, named by John Preskill in 2018, with 50 to a few hundred noisy, uncorrected qubits.
Noisy miner
Noisy miner (Manorina melanocephala), also called noisy miner bird, a large social Australian honeyeater of open eucalypt woodland and urban areas; its overabundant colonies aggressively exclude smaller birds and are a listed EPBC key threatening process.
Noisy-channel coding theorem
The noisy-channel coding theorem, proved by Claude Shannon in 1948, states that data can be transmitted with arbitrarily few errors at any rate below a channel's capacity, but not above it.
Noite na Taverna
Noite na Taverna (A Night in the Tavern) is an 1855 book of interlinked macabre tales by the Brazilian Romantic poet Manuel Antônio Álvares de Azevedo, published after his death.
Noizy
Noizy (Rigels Rajku, born 1986, Sukth, Albania) is an Albanian rapper and actor, founder of the OTR label, raised in London from 1997, with albums Pak më ndryshe through ALPHA and chart hits in Switzerland, Germany, and Austria.