Android Operating System

              Android is a mobile operating system developed by Google, based on the Linux kernel and designed primarily fortouchscreenmobile devices such assmartphonesandtablets. Android'suser interfaceis mainly based ondirect manipulation, using touch gestures that loosely correspond to real-world actions, such as swiping, tapping and pinching, to manipulate on-screen objects, along with avirtualkeyboardfor text input. In addition to touchscreen devices, Google has further developedAndroid TVfor televisions,Android Autofor cars, andAndroid Wearfor wrist watches, each with a specialized user interface. Variants of Android are also used onnotebooks,game consoles,digital cameras, and other electronics.

                       Initially developed by Android Inc., which Google bought in 2005, Android was unveiled in 2007, along with the founding of theOpen Handset Alliance – a consortium ofhardware,software, and telecommunication companies devoted to advancingopen standardsfor mobile devices. Beginning with thefirst commercial Android devicein September 2008, the operating system has gone through multiple major releases, with the current version being7.0 "Nougat", released in August 2016. Android applications ("apps") can be downloaded from theGoogle Playstore, which features over 2.7 million apps as of February 2017. Android has been the best-selling OS on tablets since 2013, and runs on the vast majority[a]of smartphones. In September 2015, Android had 1.4 billion monthly active users, and it has the largestinstalled baseof any operating system.

                   Android's source code is released by Google under anopen source license, although most Android devices ultimately ship with a combination offree and open sourceandproprietarysoftware, including proprietary software required for accessing Google services. Android is popular with technology companies that require a ready-made, low-cost and customizable operating system forhigh-techdevices. Its open nature has encouraged a large community of developers and enthusiaststo use the open-source code as a foundation for community-driven projects, which deliver updates to older devices, add new features for advanced users or bring Android to devices originally shipped with other operating systems. Historically, Android's platform fragmentation caused issues with security, in which the majority of Android devices did not receivesecurity patches, but recent developments have improved the situation. The success of Android has made it a target for patent and copyright litigation as part of the so-called "smartphone wars" between technology companies.

Animation

                               Animationis the process of making theillusionofmotionand the illusion of change[Note1]by means of the rapid displayof a sequence of images that minimally differ from each other

                               Animation creation methods include thetraditional animationcreation method and those involvingstop motionanimation of two and three-dimensional objects,paper cutouts,puppetsandclay figures. Images are displayed in a rapid succession, usually 24, 25, 30, or 60framesper second.Computer animationprocesses generating animated images with the general termcomputer-generated imagery(CGI).3D animationuses computer graphics, while2D animationis used for stylistic, low bandwidth and faster real-time renderings.

                               Early examples of attempts to capture the phenomenon ofmotioninto a still drawing can be found inpaleolithiccave paintings, where animals are often depicted with multiple legs in superimposed positions, clearly attempting to convey the perception of motion.[1]An earthen goblet discovered at the site of the 5,200-year-oldShahr-e Sūkhté(Burnt City)in southeastern Iran, depicts what could possibly be the world's oldest example of animation.[2]The artifact bears five sequential images depicting aPersian Desert Ibexjumping up to eat the leaves of a tree.[3][4]Ancient Chinese records contain several mentions of devices that were said to "give an impression of movement" to human or animal figures,[5]these accounts are unclear and may only refer to the actual movement of the figures through space.[6]They may, of course, refer to Chineseshadow puppets.In the 19th century, thephenakistoscope(1832),zoetrope(1834) andpraxinoscope(1877) were introduced.[7][8]Athaumatrope(1824) is a simple toy with a small disk with different pictures on each side; a bird in a cage and is attached to two pieces of strings.[9]The phenakistoscope was invented simultaneously by BelgianJoseph Plateauand AustrianSimon von Stampferin 1831.[10]The phenakistoscope consists of a disk with a series of images, drawn on radi evenly space around the center of the disk.[11]John Barnes Linnettpatented the first flip book in 1868 as thekineograph.[11]The commonflip bookwere early animation devices that produced an illusion of movement from a series of sequential drawings, animation did not develop further until the advent ofmotion picture filmandcinematographyin the 1890s.[12]Thecinématographewas a projector, printer, and camera in one machine that allowed moving pictures to be shown successfully on a screen which was invented by history's earliest filmmakers,Auguste and Louis Lumière, in 1894.[13][14]The first animated projection (screening) was createdin France, byCharles-Émile Reynaud,[13]who was a French science teacher. Reynaud created thePraxinoscopein 1877 and the Théâtre Optique in December 1888.[15]On 28 October 1892, he projected the first animation in public,Pauvre Pierrot, at the Musée Grévin in Paris.[16]This film is also notable as the first known instance of film perforations being used. His films were not photographed, they were drawn directly onto the transparent strip.[17]In 1900, more than 500,000 people had attended these screenings.

Dance and Rhythm

                    Rhythmand danceare deeply linked in history and practice. The American dancerTed Shawnwrote;"The conception of rhythm which underlies all studies of the dance is something about which we could talk forever, and still not finish."[13]A musical rhythm requires two main elements; first, a regularly-repeatingpulse(also called the "beat" or "tactus") that establishes thetempoand, second, a pattern ofaccentsandreststhat establishes the character of themetre or basic rhythmic pattern. The basic pulse is roughly equal in duration to a simple step or gesture.

                    Just as musical rhythms are defined by a pattern of strong and weak beats, so repetitive body movements often depends on alternating "strong" and "weak" muscular movements.[15]Given thisalternation of left-right, of forward-backward and rise-fall, along with thebilateral symmetryof thehuman body, it is natural that many dances and much music are induple and quadruple meter. However, since some such movements require more time in one phase than the other - such as the longer time required to lift a hammer than to strike - some dance rhythms fall equally naturally intotriple metre.[16]Occasionally, as inthe folk dances of the Balkans, dance traditions depend heavilyon more complex rhythms. Further, complex dances composed of a fixed sequence of steps always require phrases and melodies of a certain fixed length to accompany that sequence.

                             The very act of dancing, the steps themselves, generate an "initial skeleton of rhythmic beats" that must have preceded any separate musical accompaniment, while dance itself, as much as music, requires time-keeping[17]just as utilitarian repetitive movements such as walking, hauling and digging take on, as they become refined, something of the quality of dance

Dance and Music

                         Dance is generally, though not exclusively, performed with the accompaniment of music and may or may not be performedintimeto such music. Some dance (such astap dance) may provide its own audible accompaniment in place of (or in addition to) music. Many early forms of music and dance were created for each other and are frequently performed together. Notable examples of traditional dance/music couplings include thejig,waltz,tango,disco, andsalsa. Somemusical genreshave a parallel dance form such asbaroque musicandbaroque dance; other varieties of dance and music may share nomenclature but developed separately, such asclassical musicandclassical ballet.

Dance

                         Danceis aperformance artformconsisting of purposefully selected sequences ofhuman movement. This movement hasaestheticandsymbolicvalue, and is acknowledged as dance by performers and observers within a particularculture.[nb 1]Dance can be categorized and describedby itschoreography, by its repertoire of movements, or by itshistorical periodorplace of origin.An important distinction is to be drawn between the contexts oftheatricalandparticipatorydance,[4]although these two categories are not always completely separate; both may have special functions, whethersocial,ceremonial,competitive,erotic,martial, orsacred/liturgical. Other forms of human movement are sometimes said to have a dance-like quality, includingmartial arts,gymnastics,cheerleading,figure skating,synchronized swimmingand many other forms of athletics.

                         Theatrical dance, also called performance or concert dance, is intended primarily as a spectacle, usually aperformanceupon astagebyvirtuosodancers. It often tells astory, perhaps usingmime,costumeandscenery, or else it may simplyinterpret the musical accompaniment, which is often specially composed. Examples are westernballetandmodern dance,Classical Indian danceand Chinese and Japanese song and dance dramas. Most classical forms are centred upon dance alone, but performance dance may also appear inoperaand other forms ofmusical theatre.Participatory dance, on the other hand, whether it be afolk dance, asocial dance, agroup dancesuch as aline,circle,chainorsquare dance, or apartner dancesuch as is common in westernWestern ballroom dancing, is undertaken primarily for a common purpose, such associal interactionorexercise, of participants rather than onlookers. Such dance seldom has any narrative. A group dance and acorps de ballet, a social partner dance and apas de deux, differ profoundly. Even asolo dancemay be undertaken solely for the satisfaction of the dancer. Participatory dancersoften all employ the same movements and steps but, for example, in therave cultureofelectronic dance music, vast crowds may engage infree dance, uncoordinated with those around them. On the other hand, some cultures lay down strict rules as to the particular dances in which, for example, men, women and children may or must participate.
                             Archeologicalevidence for early dance includes 9,000-year-old paintings inIndiaat theRock Shelters of Bhimbetka, andEgyptiantomb paintings depicting dancingfigures, dated c. 3300 BC. It has been proposed that before the invention of written languages, dance was an importantpart of the oral and performance methods of passing stories down from generation to generation.[5]The use of dance inecstatictrance statesand healing rituals (as observed today in many contemporary "primitive" cultures, from the Brazilianrainforestto theKalahari Desert) is thought to have been another early factor in the social development of dance.

Nike-X

                       Nike-X was an anti-ballistic missile(ABM) system designed in the 1960s by theUS Armyto protect major cities in theUnited Statesfrom attacks by theSoviet Union'sintercontinental ballistic missile(ICBM) fleet during theCold War. The X in the name referred to its experimental basis and was supposed to be replaced by a more appropriate name when the system was put into production. This never came to pass; the Nike-X program was canceled and replaced by a much lighter defense system known asSentinel.The Nike-X system was developed in response to limitations of the earlierNike Zeussystem. Zeus' radars could only track single targets, and it was calculated that a salvo of only four ICBMs would have a 90% chance of hitting a Zeus base. Zeus would have been useful in the late 1950s when the Soviets had only a few dozen missiles, but it was of little use by the early 1960s when it was believed the Soviets would have hundreds. The attacker could also useradar reflectorsor high-altitude nuclear explosions to obscure the warheads until they were too close to attack, making a single-warhead attack highly likely to succeed.The key concept that led to Nike-X was that the rapidly thickening atmosphere below 60 kilometres(37 mi) altitude disrupted the reflectors and explosions. Nike-X was intended to wait until the enemy warheads descended below this altitude and then attack them using a very fast missile known asSprint. The entire engagement would last only a few seconds and could take place as low as 25,000 feet (7,600 m). To provide the needed speed and accuracy, as well as deal with multi-warhead attacks, Nike-X used a new radar system and building-filling computers that could track hundreds of objects at once and control salvos of many Sprints. Many dozens of warheads would need to arrive at the same time to overwhelm the system.Building a complete deployment would have been extremely expensive, on the order of the total yearly budget of theDepartment of Defense.Robert McNamara, the Secretary of Defense, felt the cost could not be justified and worried it would lead to a furthernuclear arms race. He directed the teams to consider deployments where a limited number of interceptors might still be militarily useful. Among these, the I-67 concept suggested building a lightweight defense against very limited attacks. When thePeople's Republic of Chinaexploded their firstH-bombin 1967, I-67 was promoted as a defense against a Chinese attack, and this system became Sentinel in October. Nike-X development, in its original form, ended.

Wolfenstein 3D

                  Wolfenstein 3Dis afirst-person shooter video game developed byid Softwareand published byApogee SoftwareandFormGen. Originally released on May 5, 1992, forMS-DOS, it was inspired bythe 1981Muse Softwarevideo gameCastle Wolfenstein. InWolfenstein 3D, the player assumes therole ofAlliedspyWilliam "B.J." BlazkowiczduringWorld War IIas he escapes from theNazi Germanprison Castle Wolfenstein and carries out a series of crucial missions against the Nazis. The player traverses through each of the game's levels to find an elevator to the next level or kill afinal boss, fighting Nazi soldiers, dogs, and other enemies with knives, pistols, and other guns.Wolfenstein 3Dwas the second major release by id Software, after theCommander Keenseries of episodes. In mid-1991, programmerJohn Carmackexperimented with making a fast 3Dgame engineby restricting the gameplay and viewpoint to a singleplane, producingHovertank 3DandCatacomb 3-Das prototypes. After a design session prompted the company to shift from the family-friendlyKeento a more violent theme, programmerJohn Romerosuggested remaking the 1981 stealth shooterCastle Wolfensteinas a fast-paced action game. He and designerTom Halldesigned the game, built on Carmack's engine, to be fast and violent, unlike other computer games on the market at the time.Wolfenstein 3Dfeatures artwork byAdrian Carmackand sound effects and music byBobby Prince. The game was released through Apogee in two sets of three episodes under thesharewaremodel, in which the first episode is released for free to drive interest in paying for the rest. An additional episode,Spear of Destiny, was released as a stand-alone retail title through FormGen.Wolfenstein 3Dwas a critical and commercial success, garnering numerous awards and selling over 200,000 copies by the end of 1993. It is widely regarded as having helped popularize the first-person shooter genre and establishing the standard of fast-paced action and technical prowess for many subsequent games in the genre, as well as showcasing the viability of the shareware publishing model at the time. FormGen developed an additional two episodes for the game, while Apogee released a pack of over 800 fan-created levels. Id Software never returned to the series, butdid license the engine to numerous other titles before releasing the source code for free in 1995, and multiple other games in theWolfensteinserieshave been developed by other companies since 2001.

Aircraft

                        An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of anairfoil,[1]or in a few cases the downward thrust from jet engines.The human activity that surrounds aircraft is calledaviation.Crewedaircraft are flown by an onboardpilot, butunmanned aerial vehiclesmay be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type,aircraft propulsion, usage and others.

Civil Aviation

                 Civil aviation includes all non-military flying, bothgeneral aviationandscheduled air transport.

                  Boeing, Airbus,IlyushinandTupolevconcentrate on wide-body and narrow-body jetairliners, while Bombardier, Embraer andSukhoiconcentrate onregional airliners. Large networks of specialized parts suppliers from around the world support these manufacturers, who sometimes provide only the initial design and final assembly in their own plants. The ChineseACAC consortiumwill also soonenter the civil transport market with itsComac ARJ21regional jet.[14]Until the 1970s, most major airlines wereflag carriers, sponsored by their governments and heavily protected from competition. Since then,open skiesagreements have resulted in increased competition and choice for consumers, coupled with falling prices for airlines. The combination of high fuel prices, low fares, high salaries, and crises such as theSeptember 11, 2001 attacksand theSARS epidemichave driven many older airlines to government-bailouts, bankruptcy or mergers. At the same time,low-cost carrierssuch asRyanair,SouthwestandWestjethave flourished.

Aviation Industry

                    There are early legends of human flight such as the story ofIcarusin Greek myth andJamshidin Persian myth, and later, somewhat more credible claims of short-distance human flights appear, such as the flying automaton ofArchytasofTarentum(428–347 BC),[3]the winged flights ofAbbasIbn Firnas(810–887),Eilmer of Malmesbury(11th century), and the hot-air Passarola ofBartholomeu Lourenço de Gusmão(1685–1724).

                   The modern age of aviation began with the first untethered human lighter-than-air flight on November 21, 1783, of ahot air balloondesigned by theMontgolfier brothers. The practicality of balloons was limited because they could only travel downwind. It was immediately recognized that a steerable, ordirigible, balloon was required.Jean-Pierre Blanchardflew the first human-powered dirigible in 1784 and crossed the English Channel in one in 1785.Rigid airshipsbecame the first aircraft to transport passengers and cargo over great distances. The best known aircraft of this type were manufactured by the GermanZeppelincompany.The most successful Zeppelin was theGraf Zeppelin. It flew over one million miles, including an around-the-world flight in August 1929. However, the dominance of the Zeppelins over the airplanes of that period, which had a range of only a few hundred miles, was diminishing as airplane design advanced. The "Golden Age" of the airships ended on May 6, 1937 when theHindenburgcaught fire, killing 36 people. The cause of the Hindenburg accident was initially blamed on the use of hydrogen instead of helium as the lift gas. An internal investigation by the manufacturer revealed the coating used to protect the covering material over the frame was highly flammable and allowed static electricity to build up in the airship.[4]Changes to the coating formulation reduced the risk offurther Hindenburg type accidents. Although there have been periodic initiatives to revive their use, airships have seen only niche application since that time.

                    In 1799Sir George Cayleyset forth the concept of the modern airplane as a fixed-wing flying machine with separate systems for lift, propulsion, and control.[5][6]Early dirigible developments included machine-powered propulsion (Henri Giffard, 1852), rigid frames (David Schwarz, 1896) and improved speed and maneuverability (Alberto Santos-Dumont, 1901)First powered and controlled flight by theWright Brothers, December 17, 1903There aremany competing claimsfor the earliest powered, heavier-than-air flight. The first recorded powered flight was carried out byClément Aderon October 9, 1890 when he reportedly made the first manned, powered, heavier-than-air flight of a significant distance (50 m (160 ft)) but insignificant altitude from level ground in his bat-winged, fully self-propelledfixed-wing aircraft, theAder Éole.[7][8][9]Seven years later, on 14 October 1897, Ader'sAvion IIIwas tested without success in front of two officials from theFrenchWar ministry. The report on the trials was not publicized until 1910, as they had been a military secret. In November 1906 Ader claimed to have made a successful flight on 14 October 1897, achieving an "uninterrupted flight" of around 300 metres (980 feet) on. Although widely believed at the time, these claims were later discredited.[10][11]However, the most widely accepted date is December 17, 1903 by theWright brothers. The Wright brothers were the first to fly in a powered and controlled aircraft. Previous flights were gliders (control but no power) or free flight (power but no control), but the Wright brothers combined both,setting the new standard in aviation records. Following this, the widespread adoption ofaileronsrather than wing warping made aircraft much easier to control, and only a decade later, at the start ofWorld War I, heavier-than-air powered aircraft had become practical for reconnaissance, artilleryspotting, and even attacks against ground positions.Aircraft began to transport people and cargo as designs grew larger and more reliable. The Wright brothers took aloft the first passenger, Charles Furnas, one of their mechanics, on May 14, 1908.[12][13]During the 1920s and 1930s great progress was made in the field of aviation, including the firsttransatlantic flight of Alcock and Brownin 1919,Charles Lindbergh's solo transatlantic flight in 1927, andCharles Kingsford Smith's transpacific flight the following year. One of the most successful designs of this period was theDouglas DC-3, which became the firstairlinerto be profitable carrying passengers exclusively, starting the modern era of passenger airline service. By the beginning ofWorld War II, many towns and cities had built airports, and there were numerous qualified pilots available. The war brought many innovations to aviation, including the firstjetaircraft and the first liquid-fueledrockets.

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