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QuEra
QuEra Computing is a Boston-based quantum computing company founded in 2018 as a Harvard and MIT spinout, operating Aquila, a 256-qubit neutral-atom processor available on Amazon Braket.
Quern-stone
A quern-stone, or quern, is a stone tool for hand-grinding grain into flour, with saddle and rotary forms used for most of the last ten thousand years.
Query by example
Query by example (QBE) is a retrieval method in which the user supplies a specimen, such as an image or a filled-in record, and the system returns matching items.
Query expansion
Query expansion is an information retrieval technique that adds terms of similar meaning to a user's query, so search retrieves documents the original keywords would have missed.
Query federation
Query federation executes a single query across multiple autonomous data sources through one interface, leaving data in place instead of copying it (data virtualization). Key systems include Trino, Denodo, Dremio, Teiid, and FedX; standards include SPARQL 1.1 Federated Query.
Query language
A query language, also known as a database query language, is a computer language for requesting information from a database, the dominant example being SQL.
Query optimization
Query optimization, also called query planning, is the process by which a database management system chooses the fastest or cheapest execution plan for a SQL query.
Query optimizer
A query optimizer is the component of a database management system that chooses an efficient execution plan for a SQL query, selecting join orders, algorithms, and access paths by cost.
Query plan
A query plan, also known as a query execution plan or execution plan, is the tree of scan, join, sort, and aggregate operators a database engine runs for a SQL statement.
Query string
A query string, or URL query, is the part of a URL after the question mark that carries data for the server, conventionally written as key-value pairs separated by ampersands.
Quesqui Oil and Gas Field
Quesqui is a giant onshore gas and condensate field in Huimanguillo, Tabasco, Mexico, discovered by Pemex in 2019 and announced as Mexico's biggest oil discovery since 1987.
QUEST
QUEST (QUaternion ESTimator) is a fast closed-form algorithm for spacecraft attitude determination from reference directions, published by Shuster and Oh in 1981 and used in hundreds of space missions.
QUEST (tokamak)
QUEST is a medium-sized spherical tokamak at Kyushu University in Kasuga, Fukuoka, Japan, operating since 2008 and known for fully non-inductive discharges lasting up to nearly two hours.
Questa
Questa is a functional verification platform for digital hardware designs sold by Siemens EDA, formerly Mentor Graphics, built around the QuestaSim simulator and first released in 2005.
Questar Gas Company
Questar Gas Company was a natural gas utility based in Salt Lake City, Utah, serving about 1.2 million customers until Enbridge acquired it in 2024.
Question answering
Question answering (QA) is a natural language processing task in which a computer returns a direct answer to a question instead of a list of documents.
Question Mark (aircraft)
Question Mark was a modified Atlantic-Fokker C-2A of the U.S. Army Air Corps that stayed airborne for 150 hours and 40 minutes in January 1929 through in-flight refueling.
Queue (abstract data type)
A queue is an abstract data type that stores items in first-in, first-out order, adding them at the rear with enqueue and removing them from the front with dequeue.
Queue warning
A queue warning system detects slow or stopped traffic in real time and warns approaching drivers through message signs or variable speed limits to reduce rear-end crashes.
Queueing model
A queueing model is a mathematical representation of systems where customers arrive, wait in line, and are served, used to predict congestion, queue lengths, and waiting times.
Quezon power station
The Quezon power station is a 460-MW pulverized coal-fired power plant in Mauban, Quezon, Philippines, operating since 2000 and notable as the country's first Build-Own-Operate power project.
Quibi
Quibi was a mobile-only subscription streaming service for short videos founded by Jeffrey Katzenberg and led by Meg Whitman, launched in April 2020 and shut down within six months.
QUIC
QUIC, short for Quick UDP Internet Connections, is an encrypted transport protocol running over UDP, standardized by the IETF in May 2021, and serves as the transport beneath HTTP/3.
Quick access recorder
A quick access recorder (QAR) is an aircraft flight data recorder giving airlines fast, routine access to raw flight data for safety and performance monitoring programs.
Quick Charge
Quick Charge (QC), also known as Qualcomm Quick Charge, is a proprietary fast-charging technology developed by Qualcomm that lets devices negotiate higher voltage over USB, powering over a billion devices.
Quick clay
Quick clay is a highly sensitive glaciomarine clay that keeps its structure while undisturbed but liquefies when remolded, responsible for major landslides in Scandinavia and northern North America.
QuickBird
QuickBird was a commercial Earth-imaging satellite built by Ball Aerospace and operated by DigitalGlobe of Longmont, Colorado, delivering the highest-resolution imagery then commercially available from its launch in 2001 until its retirement in 2015.
QuickBooks
QuickBooks, also known as Intuit Quickbooks, is a family of small-business accounting software from Intuit, led by cloud-based QuickBooks Online with roughly 7 million customers worldwide.
Quickselect
Quickselect, also called Hoare's selection algorithm, is a selection algorithm that finds the k-th smallest element of an unordered array. Devised by Tony Hoare, it runs in expected linear time.
Quicksort
Quicksort, also called partition-exchange sort, is a divide-and-conquer sorting algorithm that partitions an array around a pivot and recursively sorts each side. Tony Hoare invented it in 1959, and it typically runs fastest in practice.