All articles starting with S

Sparse array design

Sparse array design selects nonuniform element positions and excitation weights for an antenna array, meeting beamforming or direction-finding goals with fewer elements than a filled uniform array.

A sparse autoencoder is an autoencoder whose training adds a sparsity penalty on the code layer, keeping few units active; it underlies unsupervised feature learning and language model interpretability.

Sparse autoencoders for interpretability

Sparse autoencoders are an unsupervised technique that decomposes a neural network's activations into sparse, interpretable features, introduced for language models in 2023 by Cunningham et al. and Anthropic.

Sparse Bayesian learning

Sparse Bayesian learning is a Bayesian machine learning method that fits regression and classification models by pruning irrelevant basis functions, producing sparse models with probabilistic outputs.

Sparse canonical correlation analysis

Sparse canonical correlation analysis (sparse CCA) is a multivariate statistical method finding sparse, maximally correlated linear combinations of two variable sets, enabling feature selection in high-dimensional paired data.

Sparse channel estimation

Sparse channel estimation is a wireless signal processing method that recovers radio channel parameters from far fewer pilot measurements than classical least-squares training, by exploiting channel sparsity with compressed sensing algorithms.

Sparse code multiple access

Sparse code multiple access (SCMA) is a code-domain non-orthogonal multiple access technique proposed at Huawei in 2013, letting several users share the same radio resources.

Sparse decomposition (signal processing)

Sparse decomposition is a signal processing method representing a signal as a linear combination of a few atoms from a redundant dictionary, used in compressed sensing and machine learning.

Sparse estimation (statistics)

Sparse estimation is a class of statistical methods that fit high-dimensional models by penalizing coefficients so many are exactly zero, as in Robert Tibshirani's 1996 lasso.

Sparse feature-based mapping

Sparse feature-based mapping is a robot mapping approach that represents the environment with a small set of landmarks instead of a dense grid or point cloud.

Sparse Fourier transform

A sparse Fourier transform (SFT) is an algorithm that computes a k-sparse approximation of the discrete Fourier transform faster than the fast Fourier transform for frequency-sparse signals.

Sparse grid

A sparse grid is a numerical construction that represents high-dimensional functions on a subset of a full tensor-product grid, using the Smolyak algorithm, enabling quadrature, interpolation, and surrogate modeling in tens of dimensions.

Sparse matrix

A sparse matrix, also known as a sparse array, is a matrix in which most entries are zero; exploiting sparsity makes solving systems with millions of unknowns practical.

Sparse non-negative matrix factorization

Sparse non-negative matrix factorization (sparse NMF) decomposes a non-negative data matrix into two non-negative factors with user-set sparseness constraints, used in speech separation and hyperspectral unmixing.

Sparse optimization

Sparse optimization is a class of optimization methods that seek solutions with few nonzero variables, using sparsity-inducing penalties or constraints such as the lasso and basis pursuit.

Sparse PCA

Sparse PCA is a dimension-reduction method that performs principal component analysis under sparsity constraints, so each component combines only a few of the original variables.

Sparse principal component analysis

Sparse principal component analysis (sparse PCA) is a statistical method that makes PCA components depend on only a few variables, trading some explained variance for interpretability.

Sparse regression

Sparse regression fits a linear model while forcing most coefficients to be exactly zero, delivering both prediction and variable selection on high-dimensional data where ordinary least squares fails.

Sparse Transformer

The Sparse Transformer is a neural network architecture introduced at OpenAI in April 2019, replacing quadratic self-attention with sparse patterns that cut cost from O(n²) to O(n√n).

Sparse upcycling

Sparse upcycling is a training technique for large language models that converts a trained dense model into a mixture-of-experts model, recovering performance with about 50% of the original pretraining cost.

Sparse-view CT reconstruction

Sparse-view CT reconstruction is a computed tomography method that recovers diagnostic-quality images from far fewer projection angles than a standard scan, reducing radiation dose and acquisition time.

SparseGPT

SparseGPT is a one-shot pruning method for large language models, introduced in 2023, that prunes GPT-family models to at least 50% sparsity in a single pass without retraining.

Sparsh Shrivastava (स्पर्श श्रीवास्तव)

Sparsh Shrivastava (स्पर्श श्रीवास्तव), Indian actor-dancer-singer born 1997 in Dholpur, Rajasthan; winner of Chak Dhoom Dhoom (2010), Kundan in Balika Vadhu, Sunny in Jamtara, Deepak in Laapataa Ladies (2024).

Oct 21, 2026

Sparsholt

Sparsholt, Hampshire: village near Winchester with the Sparsholt Roman villa (excavated 1965-72 by David Johnston, mosaics in Winchester City Museum), Butser reconstruction, and Grade II Sparsholt Manor (1922-23, Triggs and Unsworth).

Sparsification (graph theory)

Graph sparsification replaces a dense weighted graph with a sparse subgraph that preserves every cut value or the Laplacian quadratic form within a small factor.

Sparsity matroid

A sparsity matroid, also called a count matroid, is a matroid defined on the edge set of a graph, where edges are independent exactly when every vertex subset spans at most k|V| − ℓ of them.

Sparta (Σπάρτη)

Sparta (Σπάρτη) was the oligarchic Greek polis of Laconia, ruled by two kings, with the agoge training system, helot serf-labor, and the Peloponnesian League; its ancient city was destroyed in 396 AD and modern Sparta founded in 1834.

Sparta Rotterdam

Sparta Rotterdam, Dutch professional football club founded 1 April 1888, oldest professional club in the Netherlands; six national titles (last 1959), three KNVB Cups, plays at Het Kasteel stadium (10,599) in Spangen, Eredivisie member.

Sparta, Laconia

Sparta (Σπάρτη) is the modern capital town of Laconia in the Peloponnese, founded in 1834 over the ruins of ancient Sparta, destroyed by the Visigoths in 396 AD; nearby are the Artemis Orthia sanctuary, theatre, Menelaion and Byzantine Mystras.