All articles starting with N
16,460 articles
Normal moveout
Normal moveout (NMO) is a seismic data processing correction that time-shifts each trace in a CMP gather by an offset-dependent amount, flattening reflections for stacking.
Normal operator
A normal operator is a linear operator on an inner product space that commutes with its adjoint, T*T = TT, the class for which the spectral theorem holds.
Normal People
Normal People is Sally Rooney's 2018 Faber novel about Connell and Marianne, Sligo teenagers whose relationship continues at Trinity College Dublin. It won the 2018 Costa Novel Award, was Booker-longlisted, and became a 2020 BBC/Hulu series.
Normal People (miniseries)
Normal People (miniseries): 2020 BBC Three/Hulu drama, 12 x 30-minute episodes, adapted by Sally Rooney and Alice Birch from Rooney's 2018 novel; directed by Lenny Abrahamson and Hettie MacDonald; stars Daisy Edgar-Jones and Paul Mescal as Marianne and Connell; 62.7 million iPlayer views, Emmy-nominated.
Normal pressure hydrocephalus
Normal pressure hydrocephalus (NPH, iNPH, Hakim-Adams syndrome) is an adult disorder with enlarged ventricles, normal CSF pressure, and the triad of gait apraxia, urinary incontinence, and dementia; treatable by ventriculoperitoneal shunt.
Normal school
Normal school (école normale) is a teacher-training institution that set the standard for pedagogy; first US state school opened in Lexington, Massachusetts, 1839, and the type evolved into teachers colleges and universities.
Normal science
Normal science is Thomas Kuhn's term for routine, puzzle-solving research conducted within an accepted scientific paradigm, introduced in his 1962 book The Structure of Scientific Revolutions.
Normal shock
A normal shock is a shock wave perpendicular to the flow direction, across which a supersonic gas decelerates abruptly to subsonic speed as its pressure, temperature, and density rise.
Normal space
A normal space is a topological space in which any two disjoint closed sets can be separated by disjoint open neighborhoods; it underlies Urysohn's lemma and the Tietze extension theorem.
Normal stress difference
A normal stress difference is a difference between diagonal stress components that develops when a complex fluid is sheared; nonzero values signal elasticity and drive the rod-climbing effect.
Normal subgroup
A normal subgroup, also called an invariant subgroup, is a subgroup H of a group G with aH = Ha for every element, equivalently fixed under conjugation by all of G.
Normal surface
A normal surface is a properly embedded surface in a triangulated 3-manifold meeting each tetrahedron in standard disks, a theory introduced by Kneser and developed by Haken in the 1960s.
Normal tension glaucoma
Normal tension glaucoma (NTG), or low-tension glaucoma, is open-angle glaucoma with IOP always ≤21 mmHg; 30–40% of OAG cases, common in Asia (up to 92% in Japan), treated by IOP reduction despite normal pressures.
Normal tissue complication probability model
The normal tissue complication probability (NTCP) model is a mathematical model in radiation oncology that converts the radiation dose to a healthy organ into an estimated complication risk.
Normal, Illinois
Normal, Illinois: McLean County town in the Bloomington-Normal twin cities, named for Illinois State Normal University. Home of Illinois State University and Rivian's EV plant; population 52,736 (2020).
Normality (chemistry)
Normality is a measure of solution concentration, expressed as equivalents of solute per liter and denoted N, still common in titration despite being obsolete in SI.
Normality test
A normality test is a statistical procedure that assesses whether a sample of data plausibly comes from a normal distribution, including the Shapiro-Wilk and Anderson-Darling tests.
Normalization
Normalization, in statistics and machine learning, adjusts data or model activations to a common scale or range, using methods such as min-max scaling and z-score standardization.
Normalization (machine learning)
Normalization in machine learning is a family of techniques that rescale a neural network's inputs, activations, or weights during training, making gradient-based optimization faster and more stable.
Normalization (statistics)
Normalization in statistics, also called normalizing variables, covers methods such as Z-score standardization and min-max scaling that prevent features with large values from dominating learning.
Normalization of antisemitism
Normalization of antisemitism: the process by which hostility toward Jews becomes accepted in mainstream discourse, distinct from 'normalization of the Jews' (Jewish emancipation). Documented via ADL, EU, and US National Strategy data on online hate, campuses, and political rhetoric.
Normalized Advantage Functions
Normalized Advantage Functions (NAF) is a reinforcement learning algorithm making Q-learning applicable to continuous action spaces, introduced by Gu, Lillicrap, Sutskever, and Levine in 2016.
Normalized difference vegetation index
The normalized difference vegetation index (NDVI) is a satellite-derived index that quantifies green vegetation density by combining near-infrared and red reflectance, used to monitor crop health, forests, and drought.
Normalized Laplacian
The normalized Laplacian is a matrix associated with a graph, formed by scaling the combinatorial Laplacian by vertex degrees; Fan Chung developed it in her book Spectral Graph Theory.
Normalizing flow
A normalizing flow is a generative model that transforms a simple distribution, usually a standard normal, into a complex one through invertible transformations, so it can both sample and compute exact likelihoods.
Normalizing flows
Normalizing flows are generative models that transform a simple base distribution, typically a Gaussian, into a complex target distribution through invertible transformations, enabling exact density evaluation and efficient sampling.
Norman
Norman, Oklahoma: third most populous Oklahoma city (128,026 in 2020 census), county seat of Cleveland County, home of the University of Oklahoma and the National Weather Center, founded 1889, incorporated 1891.
Norman A. Abrahamson
Norman A. Abrahamson is an American engineering seismologist and adjunct professor at UC Berkeley known for probabilistic seismic hazard assessment and the Next Generation Attenuation ground motion models.
Norman A. Gjostein
Norman A. Gjostein (1931–2006) was an American metallurgical engineer at Ford Motor Company, elected to the National Academy of Engineering in 1990 for surface science research.
Norman A. Phillips
Norman A. Phillips (1923–2019) was an American meteorologist who built the first general circulation model of the atmosphere, taught at MIT, and won the 2003 Benjamin Franklin Medal.