Technology and the built world

Specification (technical standard)

A specification, also called a technical specification, is a document prescribing requirements a product, process, or service must fulfill; it may be a standard, part of one, or standalone.

Specim IQ

Specim IQ is a handheld hyperspectral camera made by Specim of Oulu, Finland, introduced in 2017 and covering 400–1000 nm, used in plant phenotyping, disease detection, and cultural heritage imaging.

SPECint is the integer-performance metric of the SPEC CPU benchmark suites from the Standard Performance Evaluation Corporation, summarizing how fast a computer completes compute-intensive integer tasks.

Speckle filtering

Speckle filtering is an image processing step that reduces the granular, multiplicative noise in synthetic aperture radar imagery while preserving edges, point targets, and texture.

Spectral acceleration

Spectral acceleration is an earthquake engineering measure of the maximum acceleration a damped oscillator with a given natural period experiences in ground motion, approximating what a building experiences.

Spectral clustering

Spectral clustering is a graph-based clustering method that partitions data points using the eigenvectors of a Laplacian matrix built from a similarity graph, suited to non-convex clusters such as spirals.

Spectral embedding

Spectral embedding is a family of nonlinear dimensionality reduction methods that represent data points or graph nodes in low-dimensional space using eigenvectors of a graph Laplacian built from pairwise similarities.

Spectral kurtosis

Spectral kurtosis is a statistical signal-processing measure that shows how a signal's impulsiveness varies across frequency bands, used chiefly to select demodulation bands for bearing and gear fault diagnosis.

Spectral mixture analysis

Spectral mixture analysis (SMA) is a remote sensing technique that decomposes each pixel's spectrum into fractional abundances of endmember materials such as vegetation, soil, and impervious surface.

Spectral superchannel transmission

Spectral superchannel transmission is an optical fiber communication technique combining several closely spaced modulated subcarriers into a single high-capacity channel, each at an electrically affordable baud rate.

Spectral unmixing

Spectral unmixing, or unmixing, is a remote sensing technique that decomposes a pixel's spectrum into constituent material spectra, called endmembers, weighted by their fractional abundances, yielding sub-pixel information for mineral mapping and land-cover studies.

Spectrally selective coating

A spectrally selective coating is a microscopically thin multilayer low-E coating on window glass or film that admits visible daylight while reflecting solar ultraviolet and near-infrared heat.

Spectre (security vulnerability)

Spectre is a hardware security vulnerability, disclosed in 2018, that abuses speculative execution to leak data through cache side channels on Intel, AMD, and ARM processors.

Spectrum auction

A spectrum auction is a competitive bidding process by which a government regulator awards licenses to use radio spectrum, first held by the US FCC in 1994.

Spectrum Brands

Spectrum Brands Holdings is an American consumer products company in Middleton, Wisconsin, selling pet care, home and garden, and small appliance brands like George Foreman and Remington.

Spectrum hole

A spectrum hole is a licensed band of radio spectrum unused at a given time and place, available for opportunistic use by secondary cognitive radio users.

Spectrum Internet

Spectrum Internet is the residential and business broadband service sold by Charter Communications, offering speeds up to 1 Gbps across a 41-state footprint with unlimited data and no contracts.

Spectrum Mobile

Spectrum Mobile is a mobile virtual network operator launched by Charter Communications in 2018 for Spectrum Internet subscribers, combining WiFi with Verizon's cellular network and serving 12.5 million lines by 2026.

Spectrum occupancy measurement

Spectrum occupancy measurement is the empirical determination of how much of a radio frequency band is actually in use, using energy thresholds to classify channels as occupied or idle.

Spectrum of a sentence

The spectrum of a sentence is the set of sizes of its finite models, introduced by Heinrich Scholz in 1952; first-order spectra are exactly the NEXPTIME sets.

Spectrum prediction

Spectrum prediction, also known as spectrum inference, is the task of forecasting the future occupied or free state of radio spectrum, a core function of cognitive radio systems.

Spectrum sensing

Spectrum sensing is a cognitive radio detection method that decides whether a frequency band is occupied by a primary transmitter, so secondary users can use unused bands.

Spectrum-X

Spectrum-X is NVIDIA's Ethernet networking platform for AI data centers, announced in 2023, pairing Spectrum Ethernet switches with BlueField SuperNICs to deliver high bandwidth, low latency, and performance isolation for multi-tenant AI workloads.

Speculative decoding

Speculative decoding is an inference method for language models in which a smaller drafter proposes several tokens that the large target model verifies in a single pass, speeding generation.

Speculative execution

Speculative execution is a processor technique that computes instructions before it is certain they are needed, discarding wrong guesses; the same mechanism enables Spectre security attacks.

Speech activity detection

Speech activity detection (SAD), also called voice activity detection (VAD), is a signal processing method that separates speech from silence and noise in audio, frame by frame.

Speech coding

Speech coding compresses digitized speech into a compact bitstream for transmission or storage and reconstructs it at the receiver, spanning waveform coders, vocoders, CELP standards like AMR and Opus, and neural codecs since SoundStream in 2021.

Speech recognition

Speech recognition, also called automatic speech recognition or speech to text, converts an audio signal of spoken language into a text transcript, measured by word error rate.

Speech separation

Speech separation is the signal processing and machine learning task of recovering individual speech signals from an audio mixture, underpinning speech recognition, mobile communication, and hearing aids.