42,772 articles
Nest algebra
A nest algebra is the algebra of bounded operators on a Hilbert space leaving invariant every subspace in a nest, a totally ordered collection of closed subspaces.
Nested cross-validation
Nested cross-validation, also called double cross-validation, runs an inner tuning loop within each outer cross-validation fold, avoiding the optimistic bias of scoring a model on data used to tune it.
Nested intervals
Nested intervals are intervals of the real line, each containing the next; the nested interval property says closed, bounded nested intervals share a common point.
Nested logit model
The nested logit model is a discrete choice model grouping alternatives into nests so unobserved utilities may correlate within a group, relaxing the multinomial logit's IIA assumption.
Nested sampling
Nested sampling is a Monte Carlo algorithm in Bayesian statistics, introduced by John Skilling in 2006, that computes a model's evidence with posterior samples as a by-product.
Net (mathematics)
A net, also called a Moore–Smith sequence, is a function from a directed set into a topological space, generalizing sequences so convergence describes limits and compactness in every topology.
Net ecosystem production
Net ecosystem production (NEP) is the difference between gross primary production and ecosystem respiration in an ecosystem, commonly measured in lakes with the diel oxygen technique.
Net force
Net force is the vector sum of all external forces acting on an object, measured in newtons; internal forces cancel, and by Newton's second law the net force determines acceleration.
Net promoter score
Net promoter score (NPS) is a customer loyalty metric introduced by Fred Reichheld in 2003, calculated by subtracting the percentage of detractors from the percentage of promoters on a 0–10 recommendation question.
Net radiation
Net radiation is the difference between incoming and outgoing radiative energy at a surface or the top of the atmosphere, driving warming or cooling and Earth's energy budget.
Net Smelter Return
A net smelter return (NSR) is a royalty on mineral production calculated as a percentage of smelter proceeds, after off-site treatment and refining charges but not mining costs.
Neta Bahcall
Neta Bahcall is an Israeli-born astrophysicist, the Eugene Higgins Professor at Princeton University, known for measuring the universe's mass density with galaxy clusters and the cosmic triangle framework.
Netilmicin
Netilmicin (brand name Netromycin) is a semisynthetic aminoglycoside antibiotic developed by Schering from sisomicin, used for severe Gram-negative and staphylococcal infections and still marketed in combination eye drops.
NetKet
NetKet is an open-source Python library for studying many-body quantum systems with machine learning methods, built on JAX and introduced by Giuseppe Carleo and colleagues in 2019.
Netta Engelhardt
Netta Engelhardt is an Associate Professor of Physics at MIT who works on quantum gravity and the black hole information paradox, winning the 2021 New Horizons Prize.
Network
A network is a set of nodes connected by edges, the same structure mathematicians call a graph, used to model social relationships, the Internet, power grids, and transportation.
Network data envelopment analysis
Network data envelopment analysis (NDEA) is a nonparametric linear-programming method in operations research that measures efficiency of units split into connected sub-processes, locating where inefficiency arises.
Network matrix
A network matrix is a {0, +1, −1}-matrix built from a directed tree and graph: each entry records how a tree path traverses an arc, and it is totally unimodular.
Network meta-analysis
Network meta-analysis, also called mixed treatment comparisons, is a statistical method comparing three or more treatments in one analysis, combining direct and indirect trial evidence.
Network meta-regression
Network meta-regression (NMR) is a statistical method in evidence synthesis that extends network meta-analysis by adding study-level covariates. It estimates interactions to see if effect modification explains heterogeneity.
Network sampling
Network sampling is a family of survey methods for drawing samples of hard-to-reach, hidden populations by following links of an underlying social network instead of a complete list.
Network theory
Network theory studies systems of interconnected entities as nodes and edges, with two main strands: social network analysis and network science, both rooted in graph theory.
Network Time Protocol
The Network Time Protocol (NTP) is a protocol for synchronizing computer clocks over packet-switched networks, developed by David L. Mills and accurate to milliseconds across the Internet.
Network Time Security
Network Time Security (NTS), specified in RFC 8915 in September 2020, is an IETF standard that uses TLS and AEAD to secure the client-server mode of NTP against spoofed time packets.
Network tomography
Network tomography is a statistical method, introduced by Y. Vardi in 1996, that infers internal link delay, loss, or traffic from end-to-end measurements between edge nodes.
Neumann problem
The Neumann problem, also called the second boundary value problem, is a partial differential equation problem that prescribes the normal derivative, not the value, on the boundary.
Neumann series
The Neumann series is the infinite series of powers of a bounded linear operator, the operator analog of the geometric series, named after Carl Gottfried Neumann.
Neural coding
Neural coding is the study of how the nervous system represents information, with neurons carrying it through spike rate, spike timing, and coordinated population activity.
Neural decoding
Neural decoding, or brain decoding, converts recorded neural activity into lower-dimensional outputs such as movement trajectories or device commands, and drives brain-computer interfaces, including speech neuroprostheses decoding attempted speech into text.
Neural network decoder
A neural network decoder is a machine-learning model that maps stabilizer measurement syndromes in quantum error-correcting codes to predicted logical errors, outperforming MWPM on Google hardware.