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ATC

Air traffic control (ATC) is a service provided by ground-based controllers and appropriate authorities to prevent collisions between aircraft, between aircraft and obstacles on the maneuvering area, and to expedite and maintain an orderly flow of air traffic, while also offering advisory services on flight conditions.^[1]^[2] ATC operates through a network of facilities, including airport towers for ground and local airspace management, terminal radar approach controls for arrivals and departures, and en route centers for high-altitude navigation, utilizing radar, communication systems, and procedural separation to guide tens of thousands of daily flights in busy airspace like that managed by the U.S. Federal Aviation Administration.^[3]^[4] The system's effectiveness has enabled commercial aviation to achieve one of the safest modes of transportation, with collision prevention as its core function, supplemented by weather advisories, navigation aids, and traffic flow optimization to minimize delays.^[2]^[5] Originating in the early 1920s with rudimentary visual signaling at airports like Croydon in England to handle growing post-World War I air traffic, ATC evolved rapidly during World War II with radio communications and radar integration, leading to formalized centers by the 1940s and modern automation for handling exponential flight volumes.^[6]^[7] A defining controversy arose in 1981 when U.S. controllers, organized under the Professional Air Traffic Controllers Organization (PATCO), struck over working conditions, prompting President Reagan to dismiss over 11,000 strikers, decertify the union, and rebuild the workforce, which critics argued strained safety margins short-term but proponents credited with long-term system reforms and reduced disruptions.^[8]

Transport

Air traffic control

Air traffic control (ATC) is a ground-based service that directs the movement of aircraft to ensure safe separation, prevent collisions, and promote the efficient use of airspace.^[9] Controllers issue clearances and instructions to pilots via radio, providing real-time information on weather, traffic, and navigation while managing both departing and arriving flights.^[3] This system operates hierarchically: airport towers handle ground operations and immediate takeoffs/landings; terminal radar approach control (TRACON) facilities oversee arrivals and departures within 30-50 miles of airports; and air route traffic control centers (ARTCCs) manage en route traffic across vast regions.^[10] The origins of ATC trace to the early 20th century amid rising aviation activity, with formal rules established by the U.S. Air Commerce Act of 1926, which empowered the Department of Commerce to regulate air traffic and issue pilot licenses.^[8] The first dedicated air traffic controller was hired in 1929 at Croydon Airport in the UK, followed by U.S. implementations using visual signals, maps, and rudimentary radio by the 1930s.^[11] World War II accelerated adoption of radar for military applications, transitioning to civilian use postwar, with the U.S. Federal Aviation Administration (FAA) formed in 1958 to centralize oversight after mid-air collisions highlighted risks.^[6] Internationally, the International Civil Aviation Organization (ICAO), a UN agency established in 1944, sets global standards for ATC procedures, airspace classification, and safety protocols adopted by 193 member states.^[12] In the United States, the FAA's Air Traffic Organization (ATO), operational since 2003, manages the National Airspace System, comprising 21 ARTCCs, over 500 airport towers, and supporting facilities.^[13] Other national providers include Eurocontrol for much of Europe and Nav Canada for that country, often following ICAO guidelines but adapting to local needs.^[14] Technological foundations include primary and secondary radar for tracking, supplemented since the 2010s by Automatic Dependent Surveillance-Broadcast (ADS-B), which uses satellite-based GPS for precise aircraft positioning broadcast to controllers and pilots.^[15] The FAA's Next Generation Air Transportation System (NextGen), initiated in 2007, integrates performance-based navigation, digital communications, and automation to replace aging infrastructure, though implementation has faced delays and cost overruns exceeding $40 billion by 2025.^[16]^[17] As of 2025, U.S. ATC handles approximately 45,000 daily flights serving over 3 million passengers, supported by about 14,000 certified controllers across 313 facilities.^[18]^[19] Globally, demand for controllers is projected to require 71,000 new hires by 2034 due to traffic growth.^[20] However, persistent shortages—3,500 below targets in the U.S.—have led to mandatory overtime, six-day workweeks, and over 800 delays from staffing gaps in late 2025 alone.^[21]^[22] Key challenges include understaffing from slow hiring and training pipelines, which met only two-thirds of FAA projections from 2013-2023, exacerbating fatigue and capacity limits.^[23] Modernization efforts contend with legacy systems reliant on 1960s-1980s hardware, vulnerable to failures and incompatible with rising drone and supersonic traffic, prompting calls for full replacement rather than incremental upgrades.^[24]^[25] These issues, compounded by inconsistent funding, risk safety and efficiency as airspace demand grows 2-3% annually.^[26]

Automatic train control

Automatic train control (ATC) is a railway signalling system designed to automatically supervise train speeds, enforce speed restrictions, and prevent collisions by applying brakes if necessary, thereby enhancing safety beyond traditional manual operations.^[27] It integrates trackside equipment, such as balises or transponders, with onboard computers and sensors to continuously monitor train position, speed, and movement authority derived from signals or centralized control systems.^[28] This automation reduces human error in speed oversight and signal compliance, with systems capable of detecting overspeed conditions and initiating emergency braking within seconds.^[29] The foundational concepts of ATC trace back to early 20th-century experiments, such as those on the Great Western Railway in the United Kingdom, where initial automatic speed supervision mechanisms were tested to address limitations in manual interlocking.^[30] Practical implementations expanded post-World War II, particularly in urban rapid transit; for instance, a 1976 U.S. Office of Technology Assessment report detailed ATC's role in performing core train control functions like propulsion, braking, and protection during normal operations, minimizing operator intervention.^[31] In the United States, the mandate for Positive Train Control (PTC)—a form of ATC—followed the 2008 congressional requirement under the Rail Safety Improvement Act, driven by accidents like the 2005 Graniteville derailment, with full Class I freight implementation achieved by December 2020, preventing an estimated 1,000+ fatalities over a decade.^[32] ATC systems typically comprise three subsystems: automatic train protection (ATP) for vital safety enforcement, automatic train operation (ATO) for non-vital driving functions, and automatic train supervision (ATS) for traffic management.^[29] ATP continuously calculates braking curves based on real-time data from track circuits or radio-based position reports, enforcing limits by overriding operator inputs if violations occur, such as exceeding 5 km/h over permanent speed restrictions.^[27] Onboard vital processors use fail-safe logic to process inputs from wayside signals, ensuring collision avoidance by maintaining safe distances, often via moving-block signalling that allows dynamic headway reductions.^[28] Internationally, ATC variants adhere to regional standards for interoperability; Europe's European Train Control System (ETCS), part of the European Rail Traffic Management System (ERTMS), standardizes ATP across 28 countries as of 2023, with Level 2 implementations using GSM-R radio for continuous supervision on over 100,000 km of track.^[33] In Asia-Pacific, rapid urbanization has driven adoption, with China deploying ATC on high-speed lines covering 40,000+ km by 2022, incorporating indigenous CTCS standards akin to ETCS.^[34] The U.S. PTC, operational on 60,000 miles of track by 2021, integrates GPS, wireless communications, and onboard databases to prevent overspeed derailments and incursions into work zones.^[32] Safety analyses demonstrate ATC's efficacy in averting accidents; U.S. Federal Railroad Administration modeling projects PTC averting 714 collisions and 582 derailments annually once fully interoperable, with empirical data from early deployments showing zero overspeed-related incidents on equipped lines.^[35] Capacity gains arise from precise train spacing, enabling up to 8% throughput increases via eliminated signal delays and optimized braking.^[27] However, limitations persist: ATC primarily supervises and brakes but lacks direct propulsion control in many configurations, relying on operators for acceleration and precise station stopping, which can limit full automation in mixed-traffic environments.^[29] High initial costs—estimated at $15-20 billion for U.S. PTC rollout—and interoperability challenges with legacy infrastructure have delayed universal adoption, alongside dependencies on reliable communications that falter in adverse weather or cyber threats.^[33]^[36]

Organizations

Military organizations

The Air Training Corps (ATC) is a uniformed youth organization in the United Kingdom, sponsored by the Royal Air Force (RAF) and dedicated to fostering discipline, leadership, and aviation-related skills among individuals aged 13 to 20.^[37] It operates as part of the broader RAF Air Cadets structure, which includes over 1,500 units nationwide, emphasizing personal development through structured training rather than direct military conscription.^[37] Membership is voluntary and open to both genders, with no commitment required to enlist in the armed forces upon completion.^[38] Founded on 5 February 1941 under the Air Training Corps Act as a successor to pre-war air cadet groups, the ATC was established amid World War II to cultivate a reserve of skilled youth for potential RAF service, with King George VI serving as its inaugural Air Commodore-in-Chief.^[39] By the end of the war, it had expanded significantly, contributing to the RAF's personnel pipeline, though post-1945 it shifted focus toward broader character-building activities.^[40] Today, the organization maintains around 950 squadrons, enrolling approximately 40,000 cadets who engage in weekly parades, annual camps, and specialized courses in areas such as gliding, powered flight scholarships, and radio communications.^[41]^[38] Training programs prioritize practical skills aligned with military ethos, including drill, first aid, cybersecurity awareness, and expedition leadership, often conducted at RAF stations or dedicated cadet facilities.^[37] While not a combat unit, the ATC collaborates with regular RAF elements for joint exercises, promoting values like teamwork and resilience; data from RAF reports indicate that cadets achieve higher rates of educational attainment and employability compared to non-participants, attributed to its rigorous syllabus.^[37] Internationally, similar entities exist, such as the New Zealand Air Training Corps, modeled on the UK framework and integrated into that country's cadet forces since the mid-20th century.

Educational organizations

The Air Traffic Collegiate Training Initiative (AT-CTI), established by the Federal Aviation Administration (FAA), collaborates with accredited colleges and universities to deliver associate and bachelor's degree programs in aviation disciplines focused on air traffic control fundamentals, enabling graduates to pursue FAA controller certifications through streamlined hiring pathways. These non-engineering programs emphasize coursework in airspace management, radar procedures, and aviation regulations, with hands-on simulation training to meet FAA standards for entry-level positions. As of 2025, over 30 institutions participate in AT-CTI, providing an alternative to the FAA Academy's internal training for civilians.^[42] Embry-Riddle Aeronautical University offers a Bachelor of Science in Air Traffic Management, a four-year program integrating simulation labs and FAA-aligned curricula to prepare students for controller roles at towers, terminals, or en route centers. Vaughn College's Air Traffic Controller Program, offered in partnership with the FAA, features flexible scheduling for traditional and non-traditional students, incorporating advanced radar and communication simulations to qualify graduates for FAA knowledge tests. Florida Institute of Technology provides an Associate of Arts in Air Traffic Control, emphasizing practical dispatch and control skills, with alumni often advancing to FAA employment after passing required exams.^[43]^[44]^[45] Community colleges like Tulsa Community College deliver an Associate of Applied Science in Air Traffic Control using FAA-approved enhanced facilities for terminal and en route simulations, while Mt. San Antonio College (Mt. SAC) aligns its aeronautics curriculum directly with AT-CTI requirements for foundational controller competencies. Specialized non-degree providers, such as Advanced ATC Academy, offer intensive certification tracks for FAA or International Civil Aviation Organization (ICAO) qualifications, including classroom instruction, advanced simulations, and job placement assistance exceeding minimum FAA benchmarks. These organizations collectively address the high demand for controllers, with FAA projections indicating over 10,000 annual openings through 2030 due to retirements and traffic growth, though success requires passing rigorous FAA skills assessments post-graduation.^[46]^[47]^[48]

Other organizations

The Appalachian Trail Conservancy (ATC) is a United States-based non-profit organization founded in 1925 to oversee the 2,190-mile Appalachian National Scenic Trail spanning from Georgia to Maine. It manages trail maintenance through volunteers and staff, advocates for conservation policies, and educates the public on low-impact hiking practices, with an annual budget exceeding $20 million supported by memberships, donations, and federal grants. The ATC coordinates with the National Park Service under the National Trails System Act of 1968, having facilitated the trail's completion in 1937 after initial efforts by hiking clubs. The Applied Technology Council (ATC), established in 1971 as a nonprofit engineering research organization, focuses on developing practical tools and guidelines for reducing risks from earthquakes, tsunamis, and other natural hazards. Funded primarily by government contracts from agencies like FEMA and NSF, it has produced over 100 reports and software applications, including seismic design standards adopted in building codes across multiple states. ATC collaborates with professional societies such as the Earthquake Engineering Research Institute, emphasizing data-driven methodologies over theoretical models to inform policy and practice. Other entities include the Austin Technology Council (ATC), a business advocacy group formed in 1984 promoting innovation in Central Texas through networking events and policy influence, representing over 150 tech firms as of 2023. Smaller organizations, such as the Appropriate Technology Collaborative, develop low-cost sustainable technologies for developing regions, though their impact remains localized with limited verifiable outcomes.^[49]

Science and technology

Active thermal control systems

Active thermal control systems (ATCS) are engineered subsystems designed to regulate the temperature of spacecraft components within precise limits by actively transporting and dissipating heat using powered mechanisms, contrasting with passive methods that rely solely on material properties and geometry.^[50] These systems address the extreme thermal environments of space, where vacuum conditions prevent convective cooling and solar radiation, internal electronics, and orbital variations generate variable heat loads ranging from watts to kilowatts.^[51] ATCS maintain equipment operability by preventing overheating or freezing, typically targeting temperature ranges of -20°C to +60°C for most components, with tighter tolerances for sensitive instruments like detectors requiring stability within 1°C.^[52] Core components of ATCS include mechanically pumped fluid loops, such as single-phase ammonia or water-glycol circuits, which collect waste heat from sources via heat exchangers, transport it through insulated lines, and reject it to space via radiators.^[51] Thermostatically controlled electric heaters provide supplemental warming to counteract cold soaks during eclipse periods or low-heat scenarios, while pumps—often centrifugal or positive displacement types—circulate fluids at flow rates up to 0.5 kg/s to handle loads exceeding 10 kW per loop.^[53] Valves, sensors (e.g., thermistors and pressure transducers), and controllers enable dynamic response to thermal transients, with redundancy via multiple loops to ensure reliability against single-point failures.^[54] In operation, ATCS perform three primary functions: heat acquisition from payloads and subsystems, distribution to avoid hotspots, and rejection primarily through radiative surfaces facing deep space, where emissivity values of 0.8–0.9 optimize performance.^[51] For instance, the International Space Station's External Active Thermal Control System (EATCS), operational since 2006, employs two independent ammonia loops each capable of rejecting up to 35 kW, interfacing with photovoltaic radiator assemblies spanning over 100 m² to manage heat from U.S. Orbital Segment elements.^[51] This setup demonstrates ATCS scalability for crewed missions, where human metabolic heat (approximately 100 W per person) and life support demands necessitate robust, fault-tolerant designs with pump packages rated for over 10,000 hours of operation.^[55] Applications extend to satellites and small spacecraft, where miniaturized ATCS variants, such as the Active Thermal Architecture (ATA) for CubeSats, integrate loop heat pipes with micro-pumps to stabilize high-power payloads like infrared sensors under 1U–6U constraints.^[50] Development traces to early pumped loops using Freon-21 in the 1960s for NASA prototypes, evolving to ammonia-based systems by the Space Shuttle era for efficiency in zero-gravity boiling avoidance, with ongoing advancements focusing on variable-conductance radiators and electrocaloric devices to reduce mass by 20–30% in future missions.^[56] Challenges include fluid containment under microgravity, where two-phase flows risk dryout, and power penalties of 5–10% of total spacecraft budget, underscoring the need for hybrid passive-active integration to optimize overall efficiency.^[54]

Medicine

Anatomical Therapeutic Chemical Classification System

The Anatomical Therapeutic Chemical (ATC) Classification System categorizes active pharmaceutical ingredients according to their primary anatomical site of action, therapeutic indications, pharmacological mechanisms, and chemical structures.^[57] Maintained by the World Health Organization Collaborating Centre for Drug Statistics Methodology (WHOCC) at the Norwegian Institute of Public Health, it provides a standardized framework for international drug utilization studies, facilitating the exchange and comparison of consumption data across populations and healthcare systems.^[58] The system emphasizes uniformity in reporting to support pharmacoepidemiological research, though it does not assess clinical efficacy, safety, or therapeutic recommendations.^[59] Originating in Norway during the early 1970s under the Nordic Council on Medicines, the ATC system evolved from earlier national efforts to quantify drug consumption amid rising pharmaceutical expenditures.^[60] A pivotal 1966-1967 study by Engel and Siderius on Nordic drug use highlighted the need for a consistent classification, leading to the system's formalization.^[61] In 1981, the WHO Regional Office for Europe endorsed it as the standard for drug utilization studies, with global adoption following the establishment of the WHOCC in Oslo in 1982 to oversee maintenance, revisions, and Defined Daily Dose (DDD) assignments.^[62] Updates occur annually, incorporating new substances and reflecting evidence-based pharmacological insights, with over 6,000 codes assigned as of recent revisions.^[63] Active substances are grouped hierarchically across five levels in a seven-character alphanumeric code. The first level divides into 14 main anatomical or pharmacological groups, each represented by a letter (A: Alimentary tract and metabolism; B: Blood and blood forming organs; C: Cardiovascular system; up to V: Various).^[57] The second level adds two digits for therapeutic subgroups (e.g., A10 for blood glucose lowering drugs); the third, a single digit for pharmacological subgroups; the fourth, another digit for chemical subgroups; and the fifth, two letters or digits for specific substances (e.g., A10BA02 for metformin).^[63] This structure prioritizes the substance's most common therapeutic use, with reclassifications possible based on emerging evidence, ensuring adaptability while maintaining backward compatibility for longitudinal studies.^[64] In pharmacoepidemiology, the ATC system enables quantitative analysis of drug utilization trends, such as prescribing volumes and expenditure patterns, often paired with DDD metrics to estimate population-level exposure (e.g., DDD per 1,000 inhabitants per day).^[65] It supports regulatory pharmacovigilance, cost-effectiveness evaluations, and policy interventions by identifying overuse or underuse in specific categories, as seen in studies of antimicrobial resistance where ATC level 3 codes track antibiotic subclasses.^[66] Limitations include potential aggregation biases at higher levels, where heterogeneous subgroups may obscure nuanced patterns, necessitating complementary classifications for certain analyses.^[67] Despite these, its empirical foundation and international endorsement have made it integral to global health metrics, with mandatory use in many national drug registries since the 1990s.^[68]

Economics

Average total cost

Average total cost (ATC), also known as average cost, represents the per-unit total cost of production for a firm, encompassing both fixed and variable expenses. It is computed by dividing the total cost (TC) of producing a given quantity of output (Q) by that quantity, yielding the formula ATC = TC / Q.^[69]^[70] This metric aids firms in assessing efficiency and pricing strategies, as it reflects the average expense borne for each additional unit produced.^[71] ATC decomposes into average fixed cost (AFC), which declines continuously as output rises due to the spreading of unchanging fixed costs over more units, and average variable cost (AVC), which typically follows a U-shape influenced by variable input efficiencies. Thus, ATC = AFC + AVC.^[70] In the short run, where at least one input is fixed, the ATC curve assumes a U-shape: it initially falls as fixed costs are diluted and economies of scale in variable inputs emerge, reaches a minimum point, and then rises due to diminishing marginal returns on variable factors like labor, which elevate per-unit variable costs.^[71]^[70] This minimum ATC point signifies the output level of lowest per-unit cost, often guiding short-run profit maximization.^[72] The relationship between ATC and marginal cost (MC)—the additional cost of producing one more unit—reveals key behavioral insights: MC intersects ATC at its minimum, pulling the average downward when below ATC and upward when above, analogous to how grades affect grade-point averages.^[71] Firms minimize ATC where MC = ATC, a principle rooted in the arithmetic property that marginal values drive average trajectories.^[69] In competitive markets, short-run supply curves derive from the ATC curve's portion above AVC, as firms produce where price covers ATC for zero economic profit at equilibrium.^[70] Long-run ATC, by contrast, envelopes multiple short-run curves, achieving lower minima through scale adjustments, though the focus here remains on short-run dynamics.^[73]

Games and hobbies

Artist Trading Cards

Artist Trading Cards (ATCs) are miniature original artworks produced by artists on standardized card stock measuring 2.5 by 3.5 inches (64 by 89 mm), intended exclusively for trading to foster creative exchange and community among participants.^[74]^[75] Each card must be an original or small-edition piece, self-produced by the artist, signed with the creator's name, and dated on the reverse side, with no commercial sale permitted to preserve the non-monetary ethos of the practice.^[76]^[77] The concept originated in April 1997 when Swiss artist M. Vänçi Stirnemann created and traded the initial 1,200 cards in Zurich, Switzerland, establishing it as a collaborative cultural performance to encourage direct artist-to-artist interaction unbound by market forces.^[78]^[77] Stirnemann formalized minimal guidelines emphasizing the fixed dimensions—matching standard trading card sizes like those for baseball or playing cards—and the imperative of exchange over sale, which rapidly spread through informal sessions and mail trades.^[74] By late 1997, Stirnemann had initiated "ATC COPY-LEFT" editions, producing 333 sets of 20 copies each featuring works by 15 artists per set until 2004, further disseminating the format globally.^[79] ATCs accommodate diverse media, including drawing, painting, collage, photography, or mixed techniques on rigid supports like card stock, though deviations in material are allowed provided the size adheres strictly to standards.^[74] Trading occurs via in-person sessions, mail swaps, or online communities, with events documented worldwide since the late 1990s, such as recurring gatherings in Toulouse, France, starting September 12, 2025, at Café l'Association l'Escabel.^[80] The practice emphasizes accessibility, enabling artists of all skill levels to participate without financial barriers, and has evolved into traveling archives and exhibitions that showcase traded collections as performative installations.^[81] Despite occasional commercialization in derivative forms like Artist Exchange Cards (AECs) for sale, core ATC protocols reject monetary transactions to maintain focus on artistic dialogue.^[76]

Sports

Certified athletic trainer

A certified athletic trainer (ATC) is an allied health care professional who specializes in the prevention, diagnosis, emergency care, treatment, and rehabilitation of injuries and medical conditions related to physical activity, particularly in sports and exercise settings.^[82]^[83] These professionals work under physician direction in many jurisdictions, focusing on musculoskeletal disorders while providing first aid, protective equipment application, and patient education to minimize re-injury risks.^[84]^[85] Certification is granted by the Board of Certification (BOC), an independent nonprofit established by the National Athletic Trainers' Association (NATA).^[86] To qualify, candidates must complete a master's degree from a program accredited by the Commission on Accreditation of Athletic Training Education (CAATE), accumulate at least 500-800 hours of supervised clinical experience, and pass the BOC national examination, which tests knowledge in areas such as injury prevention, acute care, and rehabilitation.^[87]^[82] Most U.S. states regulate athletic training through licensure, typically requiring BOC certification plus state-specific jurisprudence exams and background checks; as of 2024, 49 states and the District of Columbia mandate licensure for practice.^[88] Certification maintenance involves 50 continuing education units every two years, an annual fee, and adherence to professional standards, with lapsed credentials prohibiting use of the ATC designation.^[89] The scope of practice encompasses five performance domains: preventing injuries through risk assessment and conditioning programs; conducting clinical examinations and diagnostics for neuromusculoskeletal issues; delivering immediate and emergency interventions; implementing therapeutic and rehabilitative protocols; and promoting organizational and professional health via policy development and referral coordination.^[90]^[84] Athletic trainers operate in diverse environments, including secondary schools (serving over 7 million student-athletes annually), colleges, professional sports teams, hospitals, clinics, military bases, and corporate wellness programs, often collaborating with physicians for comprehensive care.^[83]^[82] Employment data from the U.S. Bureau of Labor Statistics indicate approximately 28,000 athletic trainers employed as of May 2023, with a mean annual wage of $61,010; projections forecast 11% growth from 2024 to 2034, yielding about 2,400 annual openings due to expansion and replacements.^[91]^[83] The profession traces its formal origins to the NATA's founding in 1950, which standardized training practices previously handled informally by coaches and physicians; the BOC initiated certification exams in 1969, and the American Medical Association recognized athletic training as an allied health field in 1990, enhancing professional legitimacy and regulatory frameworks.^[92]^[93] Over 58,000 individuals held active BOC certification as of 2021, reflecting steady workforce expansion amid rising sports participation.^[94]

Other uses

Miscellaneous acronyms

Air traffic control (ATC) denotes the service provided by specialized ground facilities and personnel to guide aircraft in flight and on the ground, preventing collisions and expediting traffic flow. In the United States, the Federal Aviation Administration (FAA) oversees ATC through 21 Air Route Traffic Control Centers (ARTCCs) and over 500 airport traffic control towers, managing approximately 45,000 commercial flights daily as of fiscal year 2023.^[19] Automatic train control refers to an automated railway protection system that supervises train operations by enforcing speed restrictions and signal aspects to avert accidents. Originating in the early 1900s, it employs track circuits, balises, and onboard logic; for instance, the UK's system integrates with the European Train Control System (ETCS) for interoperability across networks.-(ATC).html) Available transfer capability (ATC) in electrical engineering is the uncommitted portion of transmission grid capacity available for scheduled electricity transfers, determined via power flow simulations to ensure system stability. Regulated under standards like those from the North American Electric Reliability Corporation (NERC), it factors in total transfer capability minus existing commitments and transmission service requirements, with values updated in intervals as short as five minutes in competitive markets. In computing, advanced transfer cache (ATC) describes an Intel processor feature enhancing data prefetching from system memory to L2 cache, introduced with the Pentium 4 architecture in 2000 to reduce latency in memory-intensive workloads.

References

[1]
14 CFR Part 1 -- Definitions and Abbreviations - eCFR
Air traffic control means a service operated by appropriate authority to promote the safe, orderly, and expeditious flow of air traffic. Air Traffic Service ( ...
[2]
Section 1. General
The primary purpose of the ATC system is to prevent a collision involving aircraft operating in the system. In addition to its primary purpose, the ATC system ...
[3]
Air Traffic | Federal Aviation Administration
The FAA provides air traffic services for the world's largest and busiest airspace. Tens of thousands of aircraft are guided safely and expeditiously every day.Flight Information · Air Traffic Facilities · Next Generation Air · Weather Observation
[4]
Air Traffic Controllers : Occupational Outlook Handbook
Air traffic controllers coordinate the movement of aircraft to maintain safe distances between them.
[5]
Air Traffic Control Service | SKYbrary Aviation Safety
Air traffic control service is a service provided for the purpose of: preventing collisions: between aircraft, and; on the manoeuvring area between aircraft and ...
[6]
Air Traffic Control | Federal Aviation Administration
Nov 16, 2021 · In December 1935, an airline consortium opened the first Airway Traffic Control Station for keeping aircraft safely separated as they moved between airports.Air Traffic Control Begins · Early Airway Traffic Control · Airway Centers in the 1940s
[7]
[PDF] The Beginnings Of The Air Traffic Control Career Field - Air University
The history of air traffic control in the United States is a history of rules and procedures. These rules and procedures were developed according to the laws ...<|control11|><|separator|>
[8]
[PDF] A History of Air Traffic Control - NATCA
In 1981, air traffic controllers lost their collective voice after the Professional Air Traffic Controllers Organization. (PATCO) was decertified.
[9]
Air Traffic Control - National Air and Space Museum
The first U.S. civilian control tower equipped with radar began operating at Indianapolis Airport in 1946. By 1951 the use of radar had begun to supercede pilot ...
[10]
Understanding Air Traffic Control | American Flyers
Air traffic control uses ARTCCs for en route, TRACONs for approach, and tower controllers for ground operations, managing complex US airspace.
[11]
The evolution of air traffic control - Globalair.com
Jun 12, 2024 · The first air traffic controller was hired in 1929 and the last 95 years have seen the role radically evolve with the industry.
[12]
About ICAO
The International Civil Aviation Organization (ICAO) is a United Nations agency which helps 193 countries to cooperate together and share their skies to their ...Air Navigation Commission · Member States · Sessions of the Council · Assembly
[13]
Air Traffic Organization - Federal Aviation Administration
Mar 3, 2025 · The Air Traffic Organization (ATO) is the operational arm of the FAA. It is responsible for providing safe and efficient air navigation services.Air Route Traffic Control... · Air Traffic Services · FAA Flight Planning Information
[14]
ICAO, EASA, Eurocontrol, FAA: What are they and what do they do?
Nov 11, 2023 · ICAO, EASA, Eurocontrol, and the FAA are all important organizations in the world of aviation. They play different roles, but they all work together.
[15]
The Future of Air Traffic Management: Why Modernizing Our Safety ...
May 8, 2025 · Key technologies such as Automatic Dependent Surveillance–Broadcast (ADS-B) and Performance-Based Navigation (PBN) were introduced to enable ...
[16]
The Evolution of Air Traffic Control Systems - eLeaP LMS
Feb 14, 2025 · NextGen was designed to modernize U.S. air traffic control using satellite-based navigation, data-sharing technologies, and advanced automation.
[17]
https://viewfromthewing.com/after-20-years-and-40-billion-air-traffic-control-modernized-nothing-faa-is-doing-it-again/
[18]
Actions from Federal Government Needed to Alleviate Air Traffic ...
Jun 18, 2025 · The FAA's air traffic control workforce of approximately 14,000 controllers spread across 313 facilities ensures that roughly 45,000 daily ...
[19]
Air Traffic By The Numbers | Federal Aviation Administration
Jul 30, 2025 · 21 air route traffic control centers 14,000+ air traffic controllers 3,000,000 plus passengers fly every day in and out of U.S. airports ...
[20]
Air Traffic Controllers Demand 2025-2034 - CAE
CAE forecast that 71000 new air traffic controllers will be needed globally by 2034 to support the growing aviation industry. Many air navigation service ...
[21]
https://www.reuters.com/business/world-at-work/air-traffic-controller-shortages-emerge-us-transportation-secretary-says-2025-10-26/
[22]
[PDF] The Air Traffic Controller Workforce Plan 2025–2028
The FAA anticipates hiring at least 8,900 new air traffic controllers through 2028, including 2,000 in 2025, and 2,200 in FY 2026, and an estimated 2,300 in FY ...
[23]
National Report Urges FAA to Overhaul Air Traffic Controller Hiring ...
Jun 25, 2025 · Karen Feigh and the 13-person committee found that the FAA hired only about two-thirds of the controllers it projected from 2013 to 2023. Due to ...
[24]
U.S. air traffic control doesn't just need to modernize — it must ...
Oct 1, 2025 · Outdated hardware, troublesome software, and a continued shortage of trained air traffic controllers has meant reduced staffing levels resulting ...
[25]
FAA Actions Are Urgently Needed to Modernize Aging Systems
Sep 23, 2024 · These challenges are due to, among other things, availability of parts, growing airspace demand, and expanding mission needs. FAA anticipates ...
[26]
Aviation Week Op-Ed: The Importance of Modernizing ... - ERAU News
Jul 22, 2025 · Another hurdle impeding the upgrade of our ATC system is inconsistent funding, despite the increasing complexity of airspace. “The FAA faces ...
[27]
Automatic Train Control | PRC Rail Consulting Ltd
A railway train is an ideal system for automation. It uses a fixed guidance system, its acceleration and braking can be predicted, its position detected, its ...
[28]
ATC Systems: The Backbone of Modern Railway Safety - Intertech Rail
Automatic Train Control (ATC) uses trackside balises and onboard readers to manage train speed, enforce signals, and enhance safety.Missing: definition | Show results with:definition
[29]
[PDF] Automatic Train Control (ATC) Update - WMATA
Sep 24, 2014 · ATO is a system that uses integrated logic between the wayside system where the train speeds and braking are regulated automatically without ...Missing: definition | Show results with:definition
[30]
Advanced Railway Signalling And Control Systems
Mar 9, 2025 · Modern railway signalling technologies. The concept of automatic train control (ATC) emerged in the early 1900s, when the Great Western ...Missing: definition | Show results with:definition<|separator|>
[31]
[PDF] Automatic Train Control in Rail Rapid Transit (Part 3 of 18)
Automatic Train Control (ATC)—the use of machines to perform all or most of the functions of train control in the normal mode of operation. Human involvement in ...
[32]
Freight Rail & Positive Train Control | AAR
PTC systems determine the precise location, direction and speed of trains, warn train operators of potential problems and safely bring the train to a stop if ...Missing: definition | Show results with:definition
[33]
Train control: Performance and reliability for ERTMS interoperability ...
Our solutions also extend beyond Europe with the first implementation of ETCS in Australia and deployment in South Africa on 600 trains, as well as in other ...
[34]
Automatic Train Protection Atp System Market Research
Sep 22, 2025 · Regionally, demand for ATP systems is witnessing significant growth in Asia-Pacific, particularly in countries like India and China, where rapid ...
[35]
[PDF] Impact of Advanced Train Control Technologies on Rail Network ...
The objective of this research was to analytically evaluate the safety and operational performance benefits of implementing advanced train control technologies ...
[36]
Automatic Train Protection (ATP) System Trends and Opportunities ...
Rating 4.8 (1,980) Jul 9, 2025 · Government Regulations: Stringent safety regulations across many nations mandate ATP implementation. Technological Advancements: Innovation ...
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Royal Air Force Air Cadets
There are over 1500 Air Training Corps (ATC), Combined Cadet Forces (CCF), Volunteer Gliding Squadrons (VGS), and Aerospace Ground Schools (AGS) across the UK ...
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About the RAF Air Cadets - Royal Air Force Benevolent Fund
Air Training Corps (ATC) is a community-based, British volunteer-military youth organisation. Founded 5 February 1941, with 900+ UK squadrons & 40000+ ...
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Our History | Royal Air Force Air Cadets
It reorganised and renamed it, and on 5 February 1941 the Air Training Corps (ATC) was officially established with King George VI as the Air Commodore-in-Chief.
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71.3.3 Air Training Corps | CLIK - DVA
The Air Training Corps is established by S8 of the Airforce Act 1923. Section 8 of the Airforce Act 1923 states: Air Training Corps.<|separator|>
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ATC Structure | Cadet Direct
The Air Training Corps has around 950 squadrons spread all over the country, with 1000's of cadets and staff. It also has it's own headquarters at RAF Cranwell.
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Collegiate Training Initiative (CTI) Schools
AT-CTI schools offer two- and four-year non-engineering aviation degrees that teach basic courses in air traffic control and aviation administration.
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Bachelor's Degree in Air Traffic Management
The B.S. in Air Traffic Management prepares students for entry-level controller positions at an FAA-designated Collegiate Training Initiative School.
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Air Traffic Controller Program | Vaughn College
Getting your air traffic control training at Vaughn College will expose you to the industry's most current and modern technology and research. Our air traffic ...
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Air Traffic Control, A.A. - Florida Tech
Prepare for an FAA air traffic controller career with Florida Tech's Air Traffic Control A.A. program—hands-on training, expert faculty and a strong ...
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Air Traffic Control, A.A.S. - Tulsa Community College
Launch your career in aviation with TCC's Air Traffic Control program. Get hands-on training in our FAA-approved, Enhanced AT-CTI facility.
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Air Traffic Control - Mt. SAC
Welcome. This curriculum meets the requirements of the Federal Aviation Administration Air Traffic Collegiate Training Initiative (AT-CTI).
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Advanced ATC Academy: Air Traffic Control School
Jul 23, 2025 · Advanced ATC is an air traffic control school that provides students with the qualifications needed to attain FAA or ICAO certifications.ATC Program Overview · About · Getting Started (FAA) · Air Traffic Control Training
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Appropriate Technology Collaborative - Great Nonprofits
Rating 5.0 (4) The Appropriate Technology Collaborative (ATC) creates new sustainable technologies that promote economic growth and improve the quality of life for low income ...
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7.0 Thermal Control - NASA
Feb 5, 2025 · Active thermal control methods rely on input power for operation and have been shown to be more effective in maintaining tighter temperature ...State-of-the-Art – Passive... · Thermal Straps · State-of-the-Art – Active Systems
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[PDF] Active Thermal Control System (ATCS) Overview - NASA
An ATCS uses a mechanically pumped fluid in closed-loop circuits to perform three functions: heat collection, heat transportation, and heat rejection. Waste ...Missing: definition | Show results with:definition
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Thermal Control System - an overview | ScienceDirect Topics
A thermal control system is defined as a system designed to maintain the temperature of spacecraft components within required limits, reduce temperature ...
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Thermal Management Subsystems - NASA
The NASA JSC Thermal Systems team is the agency focal point for engineering system management of Active Thermal Control Systems (ATCS). The team provides ...
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[PDF] Advanced Active Thermal Control Systems Architecture Study
The objective of this study is to estimate potential benefits for various proposed and under-development thermal control technologies for possible human ...
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ISS Active Thermal Control System(ATCS) Heat Exchangers and ...
Jul 1, 1997 · The International Space Station's primary external heat transport system is a single phase ammonia loop called the Active Thermal Control System (ATCS).
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[PDF] D2.1 - Study of the state of the art of Space Thermal Control Systems
Oct 4, 2019 · Development of pumps for Mechanically Pumped Fluid Loops begin with the development of an Active Thermal Control System with Freon-21 coolant ...<|control11|><|separator|>
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Anatomical Therapeutic Chemical (ATC) Classification
In the Anatomical Therapeutic Chemical (ATC) classification system, the active substances are divided into different groups according to the organ or system ...
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Anatomical Therapeutic Chemical (ATC) classification system and ...
The ATC/DDD system is a tool for exchanging and comparing data on drug use at international, national or local levels.
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Use of ATC/DDD
Nov 25, 2022 · The main purpose of the ATC/DDD system is as a tool for presenting drug utilization statistics with the aim of improving drug use.
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History - ATCDDD
Feb 15, 2018 · In 1981, the ATC/DDD system was recommended by WHO as the international standard for drug utilization studies, and in 1982 the WHO Collaborating ...
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[PDF] ATC-IDMP-presentation.pdf - UNICOM
Oct 3, 2023 · An important study by Engel and Siderius;The consumption of drugs 1966-1967 concluded that an internationally accepted classification system of ...
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ATC/DDD history - World Health Organization (WHO)
In 1981, the WHO Regional Office for Europe formally recognized the ATC/DDD system for drug utilization studies and recommended its use in Europe. In 1982 the ...
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Structure and principles - ATCDDD
Nov 10, 2022 · The active substances are classified in a hierarchy with five different levels. The system has fourteen main anatomical/pharmacological groups or 1st levels.
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[PDF] Anatomical Therapeutic Chemical (ATC) classification and the ...
Structure of the ATC code. A. ALIMENTARY TRACT AND METABOLISM. (1st level, anatomical main group). A10. DRUGS USED IN DIABETES. (2nd level, therapeutic subgroup).
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Applications of the ATC/DDD methodology
The purpose of the ATC/DDD methodology is to serve as a tool for producing good quality, usable and comparable drug utilization statistics.
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Measuring Medicine Use: Applying ATC/DDD Methodology to Real ...
Mar 17, 2021 · Each medicine is allocated a unique code using the anatomical therapeutic chemical (ATC) classification system, and a defined daily dose (DDD).
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Exploring Pharmacoepidemiologic Groupings of Drugs from a ... - NIH
Jan 23, 2015 · ATC groups drugs “according to the organ or system on which they act and their therapeutic, pharmacological and chemical properties.” [1]. ...
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[PDF] Coding and classification in drug statistics – From national to global ...
The Anatomical Therapeutic Chemical (ATC) classification system and the defined daily dose (DDD) was developed in Norway in the early seventies.
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Average Total Cost (ATC) | Formula + Calculator - Wall Street Prep
The average total cost is the total cost of production, or sum of fixed and variable costs, divided by the total quantity of output. The average total cost (ATC) ...Average Total Cost Formula · What is the Shape of the... · Average Total Cost vs...
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7.3 Costs in the Short Run - Principles of Economics 3e | OpenStax
Dec 14, 2022 · We calculate average total cost (ATC) by dividing total cost by the total quantity produced. The average total cost curve is typically U-shaped.
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Average Costs and Curves | Microeconomics - Lumen Learning
Average total cost (ATC) is calculated by dividing total cost by the total quantity produced. The average total cost curve is typically U-shaped.
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Short-run average total cost (SRATC) - (AP Microeconomics)
The U-shaped SRATC curve indicates that initially, as output increases, average total costs decrease due to the spreading of fixed costs over more units.
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Reading: Short Run and Long Run Average Total Costs
The LRAC curve is derived from this set of short-run curves by finding the lowest average total cost associated with each level of output. Again, notice that ...
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Artist Trading Cards
Artist Trading Cards are miniature works of art created on 2.5 x 3.5 inch / 64 x 89 mm card stock or any other material. they are originals, small editions ...
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Artist Trading Cards (ATCs) | The Ultimate Guide - Art by Ro
Probably the most important rule with artist trading cards is the size, and shape of the cards. The overall size of the trading card needs to be 2.5 inches by ...Missing: format | Show results with:format
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Introduction to Artist Trading Cards - The Secrets of ATCs - Tin Teddy
Generally, an ATC should never be sold, only traded or given away. In practice, many artists have embraced the small format as being ideal for affordable ...Missing: origin | Show results with:origin
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https://www.journalsay.com/blog/how-to-make-atc-cards-artist-trading-card-guide-for-beginners
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Artist Trading Cards: Home
Artist Trading Cards a collaborative cultural performance Menu. Artist Trading Cards · upcoming events · Trading Sessions · Travelling Archive Gallery ...
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ATC COPY-LEFT editions | Artist Trading Cards
Artist Trading Cards a collaborative cultural performance Menu. Artist Trading Cards ... BEAULIEU, KURT MONTREAL, QC ... STIRNEMANN, M.VÄNÇI ZÜRICH STOGOVA, OKSANA ...
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Trading Sessions | Artist Trading Cards
Over the years ATC Trading Sessions took place at many places in different countries. After i while i lost track of all the events - but here are some ...
[81]
Travelling Archive Gallery | Artist Trading Cards
We are building and running a permanent ATC exhibition archive which serves as a core/stock for further exhibition-performances.
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Athletic Training - NATA
Most require ATs to hold the Board of Certification credential of “Athletic Trainer Certified” (ATC). Learn more about the certification of athletic trainers.
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Athletic Trainers : Occupational Outlook Handbook
Athletic trainers prevent, diagnose, and treat muscle and bone injuries, provide first aid, and develop rehabilitation programs. They also apply protective ...
[84]
[PDF] BOC Standards of Professional Practice
The BOC establishes both the standards for the practice of athletic training and the continuing education requirements for BOC Certified Athletic. Trainers (ATs) ...
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[PDF] Certified Athletic Trainers
Certified athletic trainers, under physician supervision, manage athletic injuries, provide emergency care, and evaluate injuries, and make referrals.
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Board of Certification for the Athletic Trainer
BOC Approved Providers adhere to all outlined standards and guidelines ensuring exceptional credentials the public can trust.Athletic Trainer Life Cycle · Candidates · Career in Athletic Training · About BOC
[87]
Career in Athletic Training - What is an Athletic Trainer?
After finishing the degree, the student must pass a board exam through the Board of Certification (BOC) to practice in most states. ATs can go on to earn ...
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Certification Maintenance Requirements - BOC Athletic Trainer Life ...
Individuals must be legally recognized by the appropriate state regulatory agency prior to practicing athletic training. The BOC exam is recognized by all ...
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Continuing Professional Certification Renewal - BOC
Each certificate is personalized with the BOC Certified Athletic Trainer's name, ATC® credential, certification number and date of certification. Athletic ...
[90]
[PDF] Athletic Training Services - NATA
Athletic trainers provide prevention, examination, diagnosis, treatment, and rehabilitation of neuromusculoskeletal and certain medical conditions, organized ...
[91]
Athletic Trainers - Bureau of Labor Statistics
Athletic trainers evaluate and treat musculoskeletal injuries, provide preventive, therapeutic, emergency, and rehabilitative care. The mean annual wage is $61 ...
[92]
NATA History
First NATA meeting in 1950 at the Muehlebach Hotel in Kansas City where about 200 athletic trainers gathered (left). In 2018, more than 11,000 members, ...
[93]
Milestones in Athletic Trainer Certification - PMC - NIH
In this paper, I will identify the significant milestones the National Athletic Trainers' Association (NATA) and the NATA Board of Certification (NATABOC) have ...
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[PDF] The Collegiate Athletic Trainer Labor Crisis: A Data Driven Guide ...
However, as we reviewed the most recent available data we've seen an increase in Certified Athletic Trainers over the past 10 years; 58,305 in 2021 compared to ...