All articles starting with S
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Signal processing
Signal processing, also called signal theory, is a branch of electrical engineering and applied mathematics that analyzes, modifies, and synthesizes signals like sound, images, and radar returns.
Signal Protocol
The Signal Protocol, formerly known as the Axolotl protocol, is an open-source cryptographic specification providing end-to-end encryption, used by the Signal app, WhatsApp, and Google Messages.
Signal separation
Signal separation, also called blind source separation (BSS), is a family of signal processing methods that recover individual source signals from observed mixtures without knowing the mixing process.
Signal station
A signal station is a tower or building used to send messages to vessels or other stations using signals such as flags, fires, and lights.
Signal temporal logic
Signal temporal logic (STL) is a temporal logic for specifying and monitoring properties of real-valued, dense-time signals in cyber-physical systems, analog circuits, and systems biology.
Signal timing
Signal timing is the traffic engineering method of setting green, yellow, red, and all-red intervals, cycle length, green splits, and offsets between adjacent intersections to control vehicle and pedestrian flow.
Signal transduction
Signal transduction, also known as cell signaling, is the process by which a cell converts signals such as hormones and growth factors into specific responses via receptors and second messengers.
Signal transduction histidine kinase, hybrid-type, aerobic respiration control ArcB
ArcB (aerobic respiration control sensor protein, UniProt P58363) is the hybrid histidine kinase of the E. coli Arc two-component system. It signals to ArcA solely via a His292-Asp576-His717 phosphorelay and senses redox through the ubiquinone:ubiquinol ratio.
Signal transduction histidine kinase, osmosensitive K+ channel sensor, N-terminal
KdpD N-terminal domain (InterPro IPR003852), cytoplasmic ~210 aa sensor domain of osmosensitive K+ channel histidine kinases; Walker A/B ATP-binding, Usp domain; atypical serine kinase inhibiting KdpFABC; prototype E. coli KdpD/KdpE system.
Signal transduction response regulator, phosphate regulon transcriptional regulatory protein PhoB
PhoB is the cytoplasmic response regulator of the PhoR/PhoB two-component system in Escherichia coli; phosphorylation by PhoR under phosphate starvation activates dimerization, Pho box DNA binding, and transcription of the phosphate regulon.
Signal Transfer Point
A signal transfer point (STP) is a packet switch in an SS7 common-channel signaling network that routes call setup and database query messages, with voice traffic not passing through it.
Signal velocity
Signal velocity is the speed at which usable information travels through a medium, shown by Sommerfeld and Brillouin in 1914 never to exceed the speed of light.
Signal-averaged ECG
Signal-averaged ECG (SAECG), also called high-resolution ECG, detects ventricular late potentials via beat averaging; used for post-infarction arrhythmia risk stratification, with high negative but low positive predictive value.
Signal-flow graph
A signal-flow graph is a directed graph representing linear algebraic equations, introduced by Samuel J. Mason at MIT in 1953 and used in control systems.
Signal-recognition particle receptor FtsY
FtsY (Filamentation temperature sensitive X) is the single-subunit SRP receptor of bacteria and archaea, a membrane-associated GTPase homologous to eukaryotic SRα that delivers SRP-bound ribosomes to the SecYEG translocon.
Signal-to-interference-plus-noise ratio balancing
Signal-to-interference-plus-noise ratio (SINR) balancing is an optimization approach in wireless communications that adjusts transmit powers and beamforming vectors so the worst-served user's SINR is maximized under power constraints.
Signal-to-leakage-and-noise ratio
The signal-to-leakage-and-noise ratio (SLNR) is a performance metric for designing transmit beamforming and precoding in multi-user MIMO wireless systems, where it serves as an alternative to the signal-to-interference-plus-noise ratio (SINR).
Signal-to-noise ratio
The signal-to-noise ratio (SNR or S/N) is the ratio of a desired signal's power to the background noise accompanying it, usually expressed on the decibel scale.
Signalfire
SignalFire is a data-driven San Francisco venture capital firm founded by Chris Farmer, investing from pre-seed through Series B with a focus on applied AI companies.
Signalfire Breakout
SignalFire Breakout is the growth-stage fund family of SignalFire, a San Francisco venture capital firm founded in 2013 by Chris Farmer, supplying follow-on capital to scaling portfolio companies.
Signalfire Eureka
SignalFire Eureka Fund, also known as the SignalFire Eureka Fund, is a $150 million venture capital fund managed by San Francisco firm SignalFire, registered with the SEC in 2024.
Signaling game
A signaling game is a game-theoretic model in which an informed sender conveys private information to a receiver through signals, used in economics, biology, and machine learning.
Signaling threshold-regulating transmembrane adapter 1
SIT1 (SIT, SHP2-interacting transmembrane adaptor protein, gp30/40) is a transmembrane adaptor protein of T lymphocytes that negatively regulates T-cell receptor signaling, setting thymic selection thresholds; loss of function causes combined immunodeficiency.
Signalling (economics)
Signalling, also called the signaling hypothesis, is the economic theory that informed parties credibly convey private information through costly actions, as in Michael Spence's 1973 education model.
Signalling Connection Control Part
The Signalling Connection Control Part (SCCP) is a protocol layer of Signalling System No. 7 (SS7), providing connectionless and connection-oriented services above the Message Transfer Part.
Signalling System No. 6
Signalling System No. 6 (SS6) is a CCITT common-channel signaling system carrying call signals over shared links; it entered international service in 1978 between the United States, Japan, Australia, and the United Kingdom.
Signalling System No. 7
Signalling System No. 7 (SS7) is a set of common-channel signaling protocols, standardized by the CCITT in 1980, that telephone exchanges use to set up and manage calls.
Signalling theory
Signalling theory explains honest communication between parties with conflicting interests, spanning Zahavi's 1975 handicap principle, Spence's 1973 economic signaling model, and the modern view that trade-offs, not signal costs, maintain honesty.
Signals (Rush album)
Signals (1982) is the ninth studio album by Canadian rock band Rush, recorded at Le Studio, Quebec. Known for Subdivisions, the synth-forward sound, the Canadian number-one single New World Man, and as Rush's last album with producer Terry Brown.
Signals intelligence
Signals intelligence (SIGINT) is intelligence from exploiting foreign electronic emissions, covering COMINT, ELINT, FISINT, and PROFORMA; the NSA, established in 1952, leads U.S. SIGINT under Executive Order 12333 and FISA.