JAOMAD Glossary Q:
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Q—Flow rate (U.S. gallons per minute); also: means "Quantity," once meant "Event" when used in first alpha character position of ISA instrument function tag, means "Integrate" or "Totalize" when used as modifier [see ANSI/ISA S5.1-1984 (R1992)].
QA—Quality Assurance; see definition.
QAD—Quarter Amplitude Damping; method espoused by Ziegler and Nichols for tuning PID loop response to a step change.
QC—Quality Control, see definition.
QCS—Quality measurement and Control System.
QED—Quod Erat Demonstrandum; that is what has been demonstrated.
QFD—Quality Function Deployment; discipline to synchronize and optimize fabrication and assembly techniques.
QFP—Quad Flat Pack; miniature IC package.
QIC—Quarter Inch Compatibility standards group.
QML—Qualified Manufacturers List; usually refers to US military specification quality level approval for extreme conditions.
QMR—Quadruple Modular Redundant; dual one-out-of-two-with-diagnostics (1oo2D) processors in a safety system to assure system availability.
QNX—Multiuser, multitasking, real-time POSIX operating system based on microkernel technology by QNX Software Systems for PCs noted for its low-memory requirement and rapid response; similar to UNIX, it has been in use since early 1980s.
QoS—Quality of Service.
QPL—Qualified Products List.
QPSK—Quadrature Phase Shift Keying; common form of phase modulation that transmits two bits per Hertz. Thus, a 6 MHz channel supports 12 Mbps; see DPSK.
QR—Quick Response.
QRA—Quantitative Risk Analysis; used in USA for developing safety factors for control systems.
QTA—Quick Turn Around.
Qualification Protocol—In process validation, prospective experimental plan that when executed, is intended to produce documented evidence that system or subsystem has been properly qualified.
Quality—From ISO 9000 standard, total features and characteristics of product or service that bear upon its ability to satisfy stated or implied needs.
Quality Assurance—From ISO 9000 standard, all those planned and systematic actions necessary to provide adequate confidence that product or service will satisfy given requirements for quality.
Quality Control—From ISO 9000 standard, operational techniques and activities that are used to fulfill requirements for quality.
Quality Loop—From ISO 9000 standard, conceptual model of interacting activities that influence quality of product or service in various stages ranging from identification of needs to assessment of whether these needs have been satisfied.
Quality Plan—From ISO 9000 standard, document setting out specific quality practices, resources, and sequence of activities relevant to particular product, service contract, or project.
Quality Policy—From ISO 9000 standard, overall quality intentions and direction of an organization as regards quality, as formally expressed by top management.
Quality Surveillance- From ISO 9000 standard, continued monitoring and verification of the status of procedures, methods, conditions, processes, products and services, and analysis of records in relation to stated references to ensure that specified requirements for quality are being met.
Quality System—From ISO 9000 standard, organizational structure, responsibilities, procedures, processes, and resources for implementing quality management.
Quality System Review—From ISO 9000 standard, formal evaluation by top management of status and adequacy of quality system in relation to quality policy and new objectives resulting from changing circumstances.
Quantization Error—Inherent uncertainty in A/D conversion due to finite resolution of conversion process.
Quantum Computing—Future technology for designing computers based on quantum mechanics, the science of atomic structure and function; uses the "qubit," or quantum bit, which can hold infinite number of values; using technique similar to MRI scans in hospitals, computation accomplished was an ingenious search algorithm devised by Lov K. Grover of Bell Laboratories; concept is that atoms can be made to perform higher level gating functions rather than just be used to store 0s and 1s, so that such a device could factor large numbers 10,000 times faster than today's computers.
Quantum Efficiency—In photodiode, ratio of primary carriers (electron hole pairs) created to incident photons; a Quantum Efficiency of 70% means 7 out of 10 incident photons create a carrier.
QUBIT—[pronounced: kyew-bit] QUantum BIT; data bit in quantum computing; such an entity can hold more than two values, called "superposition," indicating 1 and 0 at the same time; that is, two atoms can simultaneously be in four states: 00, 01, 10 and 11; three atoms can say eight things at once: 000, 001, 010, 011, 100, 101, 110 and 111; for each atom added to the chain, number of possibilities increases exponentially, by power of 2; put together a few dozen atoms and they could perform vast numbers of calculations simultaneously; see Quantum Computing.
Query—Request for data initiated while computer program is running.
Queue—Any group of items, such as messages or computer tasks, waiting for service; this determines processing priority.
Queuing—Sequencing of batch data sessions, or any other activities, such as storing events in order of their occurrence
QWERTY—First alpha characters (second line) of "standard" typewriter keyboard; identifies somewhat universally accepted "de facto" standard computer keyboard layout of alphabet portion of key positions, as compared to placing keys in alphabetical order.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Intro