73 résultats pour "computer"
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Computer.
which can activate computer commands in conjunction with voice recognition software. “Tablet” computers are being developed that will allow users to interact with theirscreens using a penlike device. E The Central Processing Unit Information from an input device or from the computer’s memory is communicated via the bus to the central processing unit (CPU), which is the part of the computerthat translates commands and runs programs. The CPU is a microprocessor chip—that is, a single piece of sil...
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Computer Science.
theoretical research is called algorithmic complexity. Computer scientists in this field seek to develop techniques for determining the inherent efficiency of algorithmswith respect to one another. Another area of theoretical research called computability theory seeks to identify the inherent limits of computation. Software engineers use programming languages to communicate algorithms to a computer. Natural languages such as English are ambiguous—meaning that theirgrammatical structure and vocab...
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Computer Security.
might deny usage to legitimate users, and they ensure that information received from an outside source is expected and does not contain computer viruses. VII INTRUSION DETECTION SYSTEMS Security software called intrusion detection systems may be used in computers to detect unusual and suspicious activity and, in some cases, stop a variety of harmfulactions by authorized or unauthorized persons. Abuse and misuse of sensitive system and application programs and data such as password, inventory,...
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Virus (computer).
how closely it resembles a virus. It relies on experience with previous viruses to predict the likelihood that a suspicious file is an as-yet unidentified or unclassified newvirus. Other types of antiviral software include monitoring software and integrity-shell software. Monitoring software is different from scanning software. It detects illegal orpotentially damaging viral activities such as overwriting computer files or reformatting the computer's hard drive. Integrity-shell software establis...
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Hardware (computer).
Magnetic tape drives use magnetic tape similar to the tape used in VCR cassettes. Tape drives have a very slow read/write time, but have a very high capacity; in fact,their capacity is second only to hard disk drives. Tape drives are mainly used to back up data. Compact disc drives store information on pits burned into the surface of a disc of reflective material ( see CD-ROM). CD-ROMs can store up to 737 megabytes (MB) of data. A Compact Disc-Recordable (CD-R) or Compact Disc-ReWritable (CD-RW)...
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Computer Memory.
been created, information can be retrieved but not changed. Newer technologies allow ROMs to be semi-permanent—that is, the information can be changed, but ittakes several seconds to make the change. For example, a FLASH memory acts like a ROM because values remain stored in memory, but the values can be changed. C External Memory External memory can generally be classified as either magnetic or optical, or a combination called magneto-optical. A magnetic storage device, such as a computer'shar...
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Computer - Informatik.
George BooleDer britische Mathematiker und Logiker George Boole (1815-1864) veröffentlichte 1854 in seiner Abhandlung An Investigation of theLaws of Thought ein algebraisches System, das als „Boole’sche Algebra” in die Geschichte einging. Auf ihr beruhen dieFunktionsweisen von ComputernScience Source/Photo Researchers, Inc. Die erste Addiermaschine, ein Vorläufer des Digitalcomputers, wurde 1642 von Blaise Pascal erfunden. Dieses Gerät enthielt eine Reihe von zehnzähnigen Zahnrädern, beidenen je...
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Network (computer science).
computer. Since there is only one token in the network, only one computer can transmit information at a time. Token Ring networks are now quite rare. Most LANs nowuse Ethernet technology. International Business Machines Corporation (IBM), the company that invented Token Ring in the early 1980s, no longer promotes thetechnology. In the mid-1990s a new protocol called Asynchronous Transfer Mode (ATM) was introduced. This protocol encodes data in fixed-sized packets called cells rather thanvariable...
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Computer Animation.
parametric key-frame animation, interpolates, or blends, the in-between images. Another technique, algorithmic animation, controls motion by applying rules thatgovern how the objects move. When the objects and their behaviors have been specified, each scene is rendered frame-by-frame by the virtual camera and stored;then the final animated feature is played back. Despite the power of today's computers, and the innovations used to accelerate traditional animation processes, modern computer animat...
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Animation
I
INTRODUCTION
Finding Nemo
A clown fish named Marlin, left, and his friend Dory search for Marlin's son in the computer-animated feature film Finding
Nemo (2003).
Animator at WorkAnimators use computers for every part of the animation process, from creating a storyboard (a scene-by-sceneillustration of the plot) to imitating camera movement. This animator is creating a scene for the motion picture Antz(1998).C. Lepetit/Liaison Agency If an animator is basing the animation project on drawings, one of the most common animation techniques, he or she will first create a series of rough sketches thatoften will be filmed in a pencil test (simple line drawings...
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Computerspiele
1
EINLEITUNG
Computerspiele, Form der Videospiele, die im Unterschied zu Konsolenspielen auf einem Personal Computer (PC) gespielt werden.
4.2 Anstieg der Popularität in den achtziger und neunziger Jahren Die Initialzündung zum weltweiten Siegeszug von Computerspielen war 1982 die Veröffentlichung des ersten für den Heimgebrauch tauglichen Computers, desCommodore C64. Der 8-Bit-Computer wurde wegen seines vergleichsweise geringen Preises und seiner Spiel- und Programmiermöglichkeiten in kurzer Zeit insbesondereunter Jugendlichen überaus populär. Schätzungen zufolge erschienen für den C64 insgesamt mehr als 17 000 Spiele, die zunäc...
- Vocabulaire: COMPUTER, verbe.
- Vocabulaire: COMPUT, substantif masculin.
- Vocabulaire: COMPUTATION, substantif féminin.
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Internet.
usually pays a fixed monthly fee for a dedicated connection. In exchange, the company providing the connection agrees to relay data between the user’s computer andthe Internet. Dial-up is the least expensive access technology, but it is also the least convenient. To use dial-up access, a subscriber must have a telephone modem, a device thatconnects a computer to the telephone system and is capable of converting data into sounds and sounds back into data. The user’s ISP provides software that con...
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Central Processing Unit.
Development of the computer chip started in 1958 when Jack Kilby of Texas Instruments demonstrated that it was possible to integrate the various components of aCPU onto a single piece of silicon. These computer chips were called integrated circuits (ICs) because they combined multiple electronic circuits on the same chip.Subsequent design and manufacturing advances allowed transistor densities on integrated circuits to increase tremendously. The first ICs had only tens of transistorsper chip com...
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Electronic Games.
arcade game of all time. With Pizza Time Theaters legitimizing the idea of arcades and hits such as Ms. Pac-Man , Asteroids , Donkey Kong , Tempest , Frogger , and Defender bringing new excitement to gaming, the coin-operated video game business boomed. In 1981 Americans spent 75,000 person-years and $5 billion playing video games at anestimated 4,300 arcades in the United States. Many popular arcade games also were translated for use on the Atari 2600 and its chief rivals in the homemarket—M...
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World Wide Web.
browser does not display the URL for the user. Instead, to indicate that an item is selectable, the browser changes the color of the item on the screen and keeps theURL associated with the link hidden. When a user clicks on an item that corresponds to a selectable link, the browser consults the hidden information to find theappropriate URL, which the browser then follows to the selected page. Because a link can point to any page in the Web, the links are known as hyperlinks. See also Hypermedia...
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Electronic Music
I
INTRODUCTION
Electronic Music, music that requires the use of electronic devices to produce or manipulate sound during its composition and performance.
III SYNTHESIZERS AND OTHER ELECTRONIC TECHNOLOGY Moog SynthesizerThe musical synthesizer was invented by American Robert Moog. Soon after Moog introduced an early version in 1964, itbecame known as the “Moog Synthesizer,” and then simply as the “Moog.” Here, Japanese composer Isao Tomita uses aMoog synthesizer in his studio.Huynh Cong/AP/Wide World Photos In the 1950s sound synthesizers were developed, principally in the United States. Synthesizers enabled composers to produce sounds electroni...
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true love
or to play games. At the time the first computers were built the people maybe thought they were dangerous and could get out of control. Even before Asimov, some people wrote about machines that could become mightier than humans. But those presentations said that a machine, for example a computer, was like a wild beast that could kill you if you did not pay enough attention. I think Asimov's thoughts about computers and their future were not wrong. It is true that we try to improve the ...
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Chess.
There are two standard methods of recording chess moves: the algebraic system and the descriptive system. In both systems, the pieces are designated by capitalinitials: K for king, Q for queen, R for rook, B for bishop, and N for knight. The initial P for pawn is used in the descriptive system only. Castling is noted as either 0-0(“short” castling on the king’s side) or 0-0-0 (“long” castling on the queen’s side). Each square is part of both a file and a rank, and in the algebraic system, that u...
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Programming Language.
Logic languages use logic as their mathematical base. A logic program consists of sets of facts and if-then rules, which specify how one set of facts may be deducedfrom others, for example: If the statement X is true, then the statement Y is false. In the execution of such a program, an input statement can be logically deduced from other statements in the program. Many artificial intelligence programs are writtenin such languages. IV LANGUAGE STRUCTURE AND COMPONENTS Programming languages use...
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Artificial Intelligence.
Work in AI has primarily focused on two broad areas: developing logic-based systems that perform common-sense and expert reasoning, and using cognitive andbiological models to simulate and explain the information-processing capabilities of the human brain. In general, work in AI can be categorized within three research anddevelopment types: symbolic, connectionist, and evolutionary. Each has characteristic strengths and weaknesses. A Symbolic AI Symbolic AI is based in logic. It uses sequences...
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Puzzle.
Visual puzzles involve searching a picture to find hidden or disguised figures or answering a question about some part of a visual illusion. For instance, the popular 19th- century prints of American lithographic company Currier & Ives featured hidden people, animals, and other objects. A 16th-century painting from Bukhara, Uzbekistan,of a camel includes hidden figures of 17 people, 10 rabbits, a monkey, and a dragon (Metropolitan Museum of Art, New York City). B Mathematical Puzzles and Logic...
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Games.
For most of human history, a game could not gain much popularity unless it was fairly easy for players to make their own equipment. The invention of printing (whichoccurred in the mid-1400s in the West) made this process easier, but it was not until the advances of the 18th-century Industrial Revolution that it became possible tomass-produce many new varieties of games. Twentieth-century technological advances such as the invention of plastic and the computer revolution led to the creationof mor...
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Automation.
Not all industries require the same degree of automation. Agriculture, sales, and some service industries are difficult to automate. The agriculture industry may becomemore mechanized, especially in the processing and packaging of foods; however, in many service industries such as supermarkets, for example, a checkout countermay be automated and the shelves or supply bins must still be stocked by hand. Similarly, doctors may consult a computer to assist in diagnosis, but they must makethe final...
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science
of the catalyst, including selectivity for the case of more complex catalytic pathways. Figure 2B suggests the local regeneration of deactivated areas as one possible starting point for such a design. In the case of island- forming reactants, for which the reaction oc- curs at the perimeter of these islands (34,35), the generation of additional boundaries should enhance reaction rates. What are good feedback laws for these objectives, and how can they be implemented? Hierarchical con- trol schem...
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Supercomputer.
the specific model and configuration of the supercomputer. In July 1995, computer scientists at the University of Tokyo, in Japan, broke the 1 teraflop (1 trillion floating-point operations per second) mark with a computer theydesigned to perform astrophysical simulations. Named GRAPE-4 (GRAvity PipE number 4), this MPP supercomputer consisted of 1,692 interconnected processors. InNovember 1996, Cray Research debuted the CRAY T3E-900, the first commercially available supercomputer to offer teraf...
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Library (institution).
rooms, special galleries for exhibitions, auditoriums for lectures or concerts, computer rooms, children’s rooms, photocopy rooms, and classrooms. A3 Lending Materials As part of their mission to provide information resources to the community, public libraries allow users to borrow items from their collections for limited amounts of time.To be eligible to borrow public library materials, a user must register her or his name, address, and other basic information with the local library’s circulat...
- Apple Computer Incorporated - encyclopédie.
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Map - Geography.
Often only southeast slopes are hachured or shaded, giving somewhat the effect of a bird's-eye view of the area illuminated by light from the northwest. Shadings orcarefully drawn hachures, neither of which give elevations, are more easily interpreted than contour lines and are sometimes used in conjunction with them for greaterclarity. IV MAP PROJECTIONS For the representation of the entire surface of the earth without any kind of distortion, a map must have a spherical surface; a map of this...
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Dentistry.
Together with dentists, dental hygienists and dental assistants make up the team that provides dental care to patients. Hygienists record patient medical histories, suchas blood pressure and pulse. They clean teeth, apply sealants and fluoride treatments, teach patients sound oral hygiene practices, and often assist with X rays. Manyhygienists receive a two-year associate degree, while others may choose to enroll in a four-year program at a university or in a master’s degree program. There are25...
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Observatory - astronomy.
Ultraviolet radiation, X rays, and gamma rays have shorter wavelengths than visible light has. These types of radiation tell astronomers about the hottest and mostviolent phenomena in the universe. Earth’s atmosphere blocks most of this radiation, so astronomers must send their observatories above the atmosphere aboardballoons, rockets, or satellites. Ultraviolet telescopes are much like visible light telescopes, but X-ray telescopes must have special nested cylindrical mirrors to prevent Xrays...
- Art of Computer Programming (The) - encyclopédie.
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San Jose (California) - geography.
The San Jose metropolitan area is an economic powerhouse. It is the single most important high-technology center in the United States, specializing in aerospace andcomputer technology. Assisting in the area’s steady innovation is its many venture capital firms, which loan money to entrepreneurs starting new companies. It isestimated that the region contains one-half of the leading venture capital firms in the world. Among the nation’s largest companies in the San Jose metropolitan regionare Inte...
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Telescope - astronomy.
Observatory). In some telescopes designed in the 1990s, the mirror’s weight has been dramatically reduced by sandwiching a honeycomb pattern of glass ribs between a thin, butrigid, concave mirror and a flat back plate. Engineers have even developed meniscus mirrors—mirrors that are too thin to support their own weight. An adjustableframework supports the meniscus mirror, and servomechanical actuators, controlled by computer, continually adjust the shape of the mirror as it tracks celestial tar...
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Telephone.
digits is dialed. The development of inexpensive and reliable amplification provided by the introduction of the transistor in the 1960s made practical the design of adialing system based on the transmission of relatively low power tones instead of the higher-power dial pulses. Today most telephones have push buttons instead of a rotary dial. Touch-Tone is an optional service, and telephone companies still maintain the ability to receive pulsedialing. Push-button telephones usually have a switch...
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Census.
Prior to any census, a census agency must develop an accurate list of addresses and maps to ensure that everyone is counted. The U.S. Census Bureau obtainsaddresses primarily from the United States Postal Service and from previous census address lists. It also works closely with state, local, and tribal governments tocompile accurate lists. Finally, census agencies often conduct an extensive marketing campaign before Census Day to remind the general population about theimportance of responding t...
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Stock Exchange.
A Example of a Trade In an example of a trade, an investor wanting to buy 200 shares—also known as two round lots, of 100 shares each—of IBM stock will telephone or e-mail the order to abrokerage firm. This communication is normally made to an individual called a stockbroker. The investor might desire to buy the shares at the market, or current, price.On the other hand, the investor may choose to pay no more than a set amount per share. The brokerage firm then contacts one of its floor brokers...
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Chinese room argument
alone. Such an ensemble he asserts is just the wrong sort of thing literally to understand or to have a mind. Second, he tries to avoid the objection by altering his example and removing himself from the room to a wide open field and committing all the rule books to memory. In such a case he would perform all the purely formal operations in his head, re-establishing his analogy with the whole computer. He asserts he would still not understand a word of Chinese (though some of his critics claim o...
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Internet - Informatik.
Homepage im World Wide WebZahlreiche Firmen präsentieren sich mit einer Homepage (und nachfolgenden Seiten) im World Wide Web. Neben Text könnenHomepages auch andere, in digitaler Form eingebettete Objekte wie z. B. Computeranimationen, Bilder oder Videoclips enthalten.Häufig sind diese Elemente so genannte Links, über die man zu anderen Webseiten gelangt.© Microsoft Corporation. Alle Rechte vorbehalten. Das Internet unterstützt Tausende verschiedener Arten von funktionierenden und experimentell...
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Transistor.
During the late 1960s a new electronic technique, the integrated circuit, began to replace the transistor in complex electronic equipment. Although roughly the samesize as a transistor, an integrated circuit performs the function of 15 to 20 transistors. A natural development from the integrated circuit in the 1970s has been theproduction of medium-, large-, and very large-scale integrated circuits (MSI, LSI, and VLSI), which have permitted the building of a compact computer, orminicomputer, con...
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Police.
body. In larger agencies, executive officers may be selected through a civil service or merit system, after moving through the ranks from patrol officer to sergeant,lieutenant, captain, and (in still larger agencies) deputy or assistant chief. At the county level, the head of the agency usually holds the title sheriff. The sheriff is almost always elected and has the power to appoint deputies. Sheriffs'departments often provide law enforcement services for unincorporated areas of counties and ar...
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Colleges and Universities.
and (3) large universities that include undergraduate programs in addition to graduate and professional schools. D Graduate and Professional Schools Professional schools are typically divisions of large universities. They offer specialized education in a variety of professional fields, such as education, business, medicine,law, social work, agriculture, journalism, architecture, fine arts, nursing, engineering, and music. Some professional schools offer four- or five-year programs leading toa b...
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Intelligence.
education. Teachers had no way of knowing which of the “slow” students had true learning problems and which simply had behavioral problems or poor prior education.In 1904 the French Ministry of Public Instruction asked Binet and others to develop a method to objectively identify children who would have difficulty with formaleducation. Objectivity was important so that conclusions about a child’s potential for learning would not be influenced by any biases of the examiner. The governmenthoped tha...
- PC (personal computer), sigle désignant à l'origine les micro-ordinateurs d'IBM et devenu l'appellation générique de cette classe d'ordinateurs.
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Microprocessor.
thin layer of oxide about 75 angstroms deep (an angstrom is one ten-billionth of a meter). Nearly every layer that is deposited on the wafer must be patterned accurately into the shape of the transistors and other electronic elements. Usually this is done in aprocess known as photolithography, which is analogous to transforming the wafer into a piece of photographic film and projecting a picture of the circuit on it. A coatingon the surface of the wafer, called the photoresist or resist, changes...
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Wireless Communications.
were large, heavy units. After the invention of the transistor in 1948, radios shrank in size to small handheld radio transceivers. Public two-way radios with severalfrequency options are widely available as well. Usually limited in range to a few miles, these units are great aids for such mobile professionals as construction workers,film crews, event planners, and security personnel. Simpler two-way radios, called walkie-talkies, have been popular children’s toys for years. Most walkie-talkiesb...
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Automobile.
Electric motors have been used to power automobiles since the late 1800s. Electric power supplied by batteries runs the motor, which rotates a driveshaft, the shaftthat transmits engine power to the axles. Commercial electric car models for specialized purposes were available in the 1980s. General Motors Corporation introduced amass-production all-electric car in the mid-1990s. Automobiles that combine two or more types of engines are called hybrids. A typical hybrid is an electric motor with ba...
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Nanotechnology.
ever-finer method of reducing material to the nanoscale size. Instead, nanostructures would be assembled atom by atom and molecule by molecule, from the atomiclevel up, just as occurs in nature. However, assembly at this scale has its own challenges. In school, children learn about some of these challenges when they study the random Brownian motion seen in particles suspended in liquids such as water. Theparticles themselves are not moving. Rather, the water molecules that surround the particles...