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Leader-follower
Master/slave is a model of asymmetric communication or control where one device or process (the "master") controls one or more other devices or processes (the "slaves") and serves as their communication hub. In some systems, a master is selected from a group of eligible devices, with the other devices acting in the role of slaves. The ''master/slave'' terminology was first used in 1904. Since the early 21st century, the terms have become a subject of controversy from their association with slavery and some organizations have opted to replace them with alternative terms. Examples * In electronics, master/slave relationships are used to describe some of the following scenarios: ** In parallel ATA hard drive arrangements, the terms master and slave are used to describe drives on the same cable, but neither drive has control or priority over the other. ** A master clock that provides time signals used to synchronize one or more slave clocks as part of a clock network. ** In A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Model (abstract)
A conceptual model is a representation of a system. It consists of concepts used to help people know, understand, or simulate a subject the model represents. In contrast, physical models are physical object such as a toy model that may be assembled and made to work like the object it represents. The term may refer to models that are formed after a conceptualization or generalization process. Conceptual models are often abstractions of things in the real world, whether physical or social. Semantic studies are relevant to various stages of concept formation. Semantics is basically about concepts, the meaning that thinking beings give to various elements of their experience. Overview Models of concepts and models that are conceptual The term ''conceptual model'' is normal. It could mean "a model of concept" or it could mean "a model that is conceptual." A distinction can be made between ''what models are'' and ''what models are made of''. With the exception of iconic models, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loop Bin Duplicator
A loop bin duplicator is a specialized audio tape machine used in the duplication of pre-recorded audio cassettes and 8-track cartridges. Loop bin duplicators were first introduced in the early 1990s. They had fewer moving parts than previous systems, so were more reliable to operate. Analog loop bin duplicator An analog loop bin uses a long loop of either 1/2" wide (for cassette duplication) or 1" wide (for 8-track tape duplication) loaded in a large bin located in the front of the duplicator. This loop master tape is loaded into the duplicator's bin from a traditional open-reel of tape, where the program material has been recorded to it using a studio-type multitrack tape recorder in real-time beforehand. The loop tape for cassette duplication has 4 tracks on the loop bin master tape (2 stereo tracks for Side A recorded in one direction, and the other 2 for Side B recorded in the opposite direction), and for 8-tracks has all of the 8 tracks (4 2-track stereo programs) r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
County Of Los Angeles
Los Angeles County, officially the County of Los Angeles, and sometimes abbreviated as L.A. County, is the most populous county in the United States and in the U.S. state of California, with 9,861,224 residents estimated as of 2022. It is the most populous non–state-level government entity in the United States. Its population is greater than that of 40 individual U.S. states. At and with 88 incorporated cities and many unincorporated areas, it is home to more than one-quarter of California residents and is one of the most ethnically diverse counties in the United States. Its county seat, Los Angeles, is also California's most populous city and the second-most populous city in the United States, with about 3.9 million residents. In recent times, statewide droughts in California have placed great strain on the County’s (and the City of Los Angeles's) water security. History Los Angeles County is one of the original counties of California, created at the time of sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Esnault-Pelterie
Robert Albert Charles Esnault-Pelterie (8 November 1881 – 6 December 1957) was a French aircraft designer and spaceflight theorist. He is referred to as being one of the founders of modern rocketry and astronautics, along with the Russian Konstantin Tsiolkovsky, the Chinese Qian Xuesen, Germans Hermann Oberth, Fritz von Opel, Wernher Von Braun and the American Robert H. Goddard. Biography He was born on 8 November 1881 in Paris to a textile industrialist. He was educated at the ''Faculté des Sciences'', studying engineering at the Sorbonne. He served in World War I and was made an ''Officier de la Légion d'Honneur''. In November 1928, on board the ''Ile de France'' while sailing to New York City, he was married to Carmen Bernaldo de Quirós, the daughter of Don Antonio and Yvonne Cabarrus, and granddaughter of General Marquis of Santiago, Grandee of Spain, Head of the Military Household of Queen Isabella II. He died on 6 December 1957 in Nice, France. REP Esnault-Pel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malcolm Loughead
Malcolm Lockheed ((né Malcolm Loughead; - ) was an American aviation engineer who formed the Alco Hydro-Aeroplane Company along with his brother, Allan Loughead, also known as Allan Lockheed. This company went on to become the Lockheed Corporation. Life Loughead was the son of Flora and John Loughead. He had a half-brother Victor, a sister Hope, and a brother Allan Lockheed. Loughead also patented the first hydraulic brakes in 1917; these were adopted by Duesenberg Duesenberg Automobile and Motors Company, Inc. was an American race car, racing and luxury car, luxury automobile manufacturer founded in Indianapolis, Indiana, by brothers Fred Duesenberg, Fred and August Duesenberg in 1920. The company is ... for their 1921 Model A., p. 61. In 1919, Malcolm and his brother Allen were awarded the Order of the Golden Crown by King Albert of Belgium. Notes ReferencesAllan and Malcolm Loughead (Lockheed) Their Early Lives in the Santa Cruz Mountains 1886 births 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Brake
A hydraulic brake is an arrangement of braking mechanism which uses brake fluid, typically containing glycol ethers or diethylene glycol, to transfer pressure from the controlling mechanism to the braking mechanism. History During 1904, Frederick George Heath (Heath Hydraulic Brake Co., Ltd.), Redditch, England devised and fitted a hydraulic (water/glycerine) brake system to a cycle using a handlebar lever and piston. He obtained patent GB190403651A for “Improvements in hydraulic actuated brakes for cycles and motors”, as well as subsequently for improved flexible rubber hydraulic pipes. In 1908, Ernest Walter Weight of Bristol, England devised and fitted a four-wheel hydraulic (oil) braking system to a motor car. He patented it in Great Britain (GB190800241A) in December 1908, later in Europe and the USA and then exhibited it at the 1909 London Motor Show. His brother, William Herbert Weight improved the patent (GB190921122A) and both were assigned to the Weight Patent Autom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNS Zone Transfer
DNS zone transfer, also sometimes known by the inducing DNS query type AXFR, is a type of DNS transaction. It is one of the many mechanisms available for administrators to replicate DNS databases across a set of DNS servers. A zone transfer uses the Transmission Control Protocol (TCP) for transport, and takes the form of a client–server transaction. The client requesting a zone transfer may be a secondary server requesting data from a primary server. The portion of the database that is replicated is a zone. Operation Zone transfer consists of a preamble, followed by the actual data transfer. The preamble comprises a lookup of the Start of Authority (SOA) resource record for the "zone apex", the node of the DNS namespace that is at the top of the "zone". The fields of this SOA resource record, in particular the "serial number", determine whether the actual data transfer need to occur at all. The client compares the serial number of the SOA resource record with the serial num ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Vixie
Paul Vixie is an American computer scientist whose technical contributions include Domain Name System (DNS) protocol design and procedure, mechanisms to achieve operational robustness of DNS implementations, and significant contributions to open source software principles and methodology. He also created and launched the first successful commercial anti-spam service. He authored the standard UNIX system programs ''SENDS'', ''proxynet'', ''rtty'' and Vixie cron. At one point he ran his own consulting business, Vixie Enterprises. Career Vixie was a software engineer at Digital Equipment Corporation (DEC) from 1988 to 1993. After he left DEC in 1994, he founded Internet Software Consortium (ISC) in 1996 together with Rick Adams and Carl Malamud to support BIND and other software for the Internet. The activities of ISC were assumed by a new company, Internet Systems Consortium in 2004. Although ISC operates the F root name server, Vixie at one point joined the Open Root Server Netw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brake
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction. Background Most brakes commonly use friction between two surfaces pressed together to convert the kinetic energy of the moving object into heat, though other methods of energy conversion may be employed. For example, regenerative braking converts much of the energy to electrical energy, which may be stored for later use. Other methods convert kinetic energy into potential energy in such stored forms as pressurized air or pressurized oil. Eddy current brakes use magnetic fields to convert kinetic energy into electric current in the brake disc, fin, or rail, which is converted into heat. Still other braking methods even transform kinetic energy into different forms, for example by transferring the energy to a rotating flywheel. Brakes are generally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Master Cylinder
In automotive engineering, the master cylinder is a control device that converts force (commonly from a driver's foot) into hydraulic pressure. This device controls slave cylinders located at the other end of the hydraulic brake system. As piston(s) move along the bore of the master cylinder, this movement is transferred through the hydraulic fluid, to result in a movement of the slave cylinder(s). The hydraulic pressure created by moving a piston (inside the bore of the master cylinder) toward the slave cylinder(s) compresses the fluid evenly, but by varying the comparative surface area of the master cylinder and each slave cylinder, one can vary the amount of force and displacement applied to each slave cylinder, relative to the amount of force and displacement applied to the master cylinder. Vehicle applications The most common vehicle uses of master cylinders are in brake and clutch systems. In brake systems, the operated devices are cylinders inside brake calip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple-unit Train Control
Multiple-unit train control, sometimes abbreviated to multiple-unit or MU, is a method of simultaneously controlling all the traction equipment in a train from a single location—whether it is a multiple unit comprising a number of self-powered passenger cars or a set of locomotives—with only a control signal transmitted to each unit. This contrasts with arrangements where electric motors in different units are connected directly to the power supply switched by a single control mechanism, thus requiring the full traction power to be transmitted through the train. A set of vehicles under multiple unit control is referred to as a consist in the United States. Origins Multiple unit train control was first used in electric multiple units in the 1890s. The Liverpool Overhead Railway The Liverpool Overhead Railway opened in 1893 with two-car electric multiple units, controllers in cabs at both ends directly controlling the traction current to motors on both cars. Frank J. Spragu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Locomotive
A locomotive or engine is a rail transport vehicle that provides the Power (physics), motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, Motor coach (rail), motor coach, railcar or power car; the use of these self-propelled vehicles is increasingly common for passenger trains, but rare for freight (see CargoSprinter). Traditionally, locomotives pulled trains from the front. However, Push-pull train, push-pull operation has become common, where the train may have a locomotive (or locomotives) at the front, at the rear, or at each end. Most recently railroads have begun adopting DPU or distributed power. The front may have one or two locomotives followed by a mid-train locomotive that is controlled remotely from the lead unit. __TOC__ Etymology The word ''locomotive'' originates from the Latin language, Latin 'from a place', Ablative case, ablative of 'place', and the Medieval Latin 'causing mot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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