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Spatial disorientation in aviation
Spatial disorientation in aviation is a pilot's inability to correctly interpret an aircraft's attitude, altitude, or airspeed when vision and the inner ear give misleading cues in flight.
Spatial intelligence
Spatial intelligence, in Fei-Fei Li's usage, is AI that understands, generates, and interacts with complex 3D worlds, driving World Labs and a 2024–2026 wave of world-model companies.
Spatial modulation
Spatial modulation is a MIMO wireless technique where information bits are carried both by a signal symbol and by the index of the one active transmit antenna.
Spatial pyramid matching
Spatial pyramid matching (SPM) is a computer vision technique that compares images by matching histograms of local features over increasingly fine sub-regions, introduced at CVPR 2006.
Spatio-temporal clustering
Spatio-temporal clustering is a data mining method that groups points close in both space and time, applied to GPS tracks, crime hotspots, and Twitter event detection.
Spatio-temporal data mining
Spatio-temporal data mining (STDM) extracts useful patterns from large datasets where every measurement carries a location and a timestamp, such as GPS trajectories, sensor readings, and evolving weather maps.
Spatiotemporal graph convolutional network
A spatiotemporal graph convolutional network (STGCN) is a neural architecture combining graph convolutions over sensor networks with temporal convolutions, introduced in 2018 for traffic forecasting and skeleton-based action recognition.
Spatiotemporal modulation in metasurfaces
Spatiotemporal modulation in metasurfaces is the variation of a metasurface's parameters in space and time, letting it change a wave's direction and frequency and break reciprocity.
SPDX
SPDX (System Package Data Exchange) is a Linux Foundation open standard for software bill of materials data, covering licenses, dependencies, and security, and published as ISO/IEC 5962:2021.
SPE Petroleum Resources Management System
The SPE Petroleum Resources Management System (PRMS) is the worldwide standard for classifying oil and gas reserves and resources, first issued in 2007 and updated in 2018.
Speaker diarization
Speaker diarization is the artificial intelligence task of partitioning an audio or video recording into segments by speaker identity, answering who spoke when with anonymous labels such as Speaker A and Speaker B.
Speaker separation
Speaker separation is a signal processing and machine learning method that extracts one speech signal per speaker from an audio mixture of two or more overlapping voices.
Spear
A spear is a weapon consisting of a long shaft with a pointed head of stone, bone, or metal, used for thrusting or throwing, and among the oldest human weapons.
SPEAR 3
SPEAR 3 (Selected Precision Effects At Range) is a British miniature cruise missile developed by MBDA for the UK's F-35B and Typhoon aircraft, with a range exceeding 100 km.
Spear-thrower
The spear-thrower, also called the atlatl, is a handheld rod, strap, or board that uses leverage to launch a spear or dart faster and farther than the arm alone.
Spearfish torpedo
The Spearfish torpedo is a British 533 mm heavyweight torpedo launched from Royal Navy submarines since 1994, built to sink fast, deep-diving submarines and surface warships.
Spearhead Oil Pipeline
The Spearhead Oil Pipeline, also called Enbridge Line 55, is a 583-mile Enbridge crude oil pipeline from Flanagan, Illinois, to Cushing, Oklahoma, in reversed service since 2006.
Spearhead-class expeditionary fast transport
The Spearhead-class expeditionary fast transport, formerly the Joint High Speed Vessel, is a class of United States Navy catamarans carrying troops and cargo at over 35 knots within a theater.
SPEC CPU
SPEC CPU is a family of computer benchmark suites from the Standard Performance Evaluation Corporation that measures compute-intensive performance by compiling and running real application source code.
Special Administrative Unit of Civil Aeronautics (Colombia)
The Special Administrative Unit of Civil Aeronautics, known as Aerocivil, is Colombia's civil aviation authority, a technical entity under the Ministry of Transport that regulates airspace, provides navigation services, and investigates accidents.
Special Atomic Demolition Munition
The Special Atomic Demolition Munition (SADM) was a man-portable US nuclear backpack weapon built around the W54 warhead, carried by trained soldiers and deployed from 1964 to 1989.
Special moment-resisting frame
A special moment-resisting frame, or SMF, is a highly ductile seismic force-resisting system of rigidly joined beams and columns, permitted in high seismic design categories.
Special protection scheme
A special protection scheme (SPS), also known as a remedial action scheme (RAS) or system integrity protection scheme (SIPS), detects abnormal grid conditions and takes corrective actions such as tripping generators or shedding load.
Special reconnaissance
Special reconnaissance is a military term for reconnaissance and surveillance in hostile, denied, or politically sensitive environments, using capabilities not normally found in conventional forces.
Specialized Bicycle Components
Specialized Bicycle Components, also known as Specialized Bicycles, is an American bicycle maker founded by Mike Sinyard in 1974 and based in Morgan Hill, California.
Specially Designated Global Terrorist
A Specially Designated Global Terrorist (SDGT) is a person or entity the United States designates under Executive Order 13224 of 2001 for committing or supporting terrorism, blocking their property.
Specific energy (open-channel flow)
Specific energy in open-channel flow is the energy of flowing water per unit weight relative to the channel bottom, equal to depth plus velocity head, and it classifies flow as subcritical, critical, or supercritical.
Specific range
Specific range is a measure of aircraft cruise efficiency, the distance flown per unit of fuel consumed, and the aviation counterpart of an automobile's miles per gallon.
Specific speed
Specific speed is a characteristic index number for rotodynamic pumps that condenses best-efficiency speed, flow, and head into one value for comparing and classifying impellers.
Specific thrust
Specific thrust is the thrust produced by a jet engine divided by the mass flow rate of air through it, letting engines of different sizes be compared directly.