Raw data known as primary data, is data collected from a source. If a scientist sets up a computerized thermometer which records the temperature of a chemical mixture in a test tube every minute, the list of temperature readings for every minute, as printed out on a spreadsheet or viewed on a computer screen is "raw data". Raw data has not been subjected to processing, "cleaning" by researchers to remove outliers, obvious instrument reading errors or data entry errors, or any analysis; as well, raw data has not been subject to any other manipulation by a software program or a human researcher, analyst or technician. It is referred to as primary data. Raw data is a relative term, because once raw data has been "cleaned" and processed by one team of researchers, another team may consider this processed data to be "raw data" for another stage of research. Raw data can be inputted to a computer program or used in manual procedures such as analyzing statistics from a survey; the term "raw data" can refer to the binary data on electronic storage devices, such as hard disk drives.
Data has two ways of being generated. The first is what is called'captured data', is found through purposeful investigation or analysis; the second is called'exhaust data', is gathered by machines or terminals as a secondary function. For example, cash registers and speedometers serve a main function but may collect data as a secondary task. Exhaustive data is too large or of little use to process and becomes'transient' or thrown away. In computing, raw data may have the following attributes: it may contain human, machine, or instrument errors, it may not be validated. For example, a data input sheet might contain dates as raw data in many forms: "31st January 1999", "31/01/1999", "31/1/99", "31 Jan", or "today". Once captured, this raw data may be processed stored as a normalized format a Julian date, to make it easier for computers and humans to interpret during processing. Raw data are the data input to processing. A distinction is made between data and information, to the effect that information is the end product of data processing.
Raw data that has undergone processing are sometimes referred to as "cooked" data in a colloquial sense. Although raw data has the potential to be transformed into "information," extraction, organization and formatting for presentation are required before raw data can be transformed into usable information. For example, a point-of-sale terminal in a busy supermarket collects huge volumes of raw data each day about customers' purchases. However, this list of grocery items and their prices and the time and date of purchase does not yield much information until it is processed. Once processed and analyzed by a software program or by a researcher using a pen and paper and a calculator, this raw data may indicate the particular items that each customer buys, when they buy them, at what price; this processed and analyzed data provides information for the manager, that the manager could use to help her determine, for example, how many cashiers to hire and at what times. Such information could become data for further processing, for example as part of a predictive marketing campaign.
As a result of processing, raw data sometimes ends up being put in a database, which enables the raw data to become accessible for further processing and analysis in any number of different ways. Tim Berners-Lee argues. Inspired by a post by Rufus Pollock of the Open Knowledge Foundation his call to action is "Raw Data Now", meaning that everyone should demand that governments and businesses share the data they collect as raw data, he points out that "data drives a huge amount of what happens in our lives… because somebody takes the data and does something with it." To Berners-Lee, it is from this sharing of raw data, that advances in science will emerge. Advocates of open data argue that once citizens and civil society organizations have access to data from businesses and governments, it will enable citizens and NGOs to do their own analysis of the data, which can empower people and civil society. For example, a government may claim that its policies are reducing the unemployment rate, but a poverty advocacy group may be able to have its staff econometricians do their own analysis of the raw data, which may lead this group to draw different conclusions about the data set.
Give Us the Data Raw, Give it to Us Now - the blog post from Rufus Pollock that inspired Tim Berners-Lee Tim Berners-Lee Gives the Web a New Definition
A primary mirror is the principal light-gathering surface of a reflecting telescope. The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal, or in telescopes, glass or other material coated with a reflective layer. One of the first known reflecting telescopes, Newton's reflector of 1668, used a 3.3 cm polished metal primary mirror. The next major change was to use silver on glass rather than metal, in the 19th century such was with the Crossley reflector; this was changed to vacuum deposited aluminum on glass, used on the 200-inch Hale telescope. Solid primary mirrors have to sustain their own weight and not deform under gravity, which limits the maximum size for a single piece primary mirror. Segmented mirror configurations are used to get around the size limitation on single primary mirrors. For example, the Giant Magellan Telescope will have seven 8.4 meter primary mirrors, with the resolving power equivalent to a 24.5 m optical aperture.
The largest optical telescope in the world as of 2009 to use a non-segmented single-mirror as its primary mirror is the 8.2 m Subaru telescope of the National Astronomical Observatory of Japan, located in Mauna Kea Observatory on Hawaii since 1997. S./German/Italian Large Binocular Telescope has two 8.4 m mirrors. Both of these are smaller; the Hubble Space Telescope has a 2.4 m primary mirror. Radio and submillimeter telescopes use much larger dishes or antennae, which do not have to be made as as the mirrors used in optical telescopes; the Arecibo Observatory uses a 305 m dish, the world largest single-dish radio telescope fixed to the ground. The Green Bank Telescope has the world's largest steerable single radio dish with 100 m in diameter. There are larger radio arrays, composed of multiple dishes which have better image resolution but less sensitivity. Active optics Honeycomb mirror Liquid mirror telescope List of largest optical reflecting telescopes List of telescope parts and construction Mirror mount Mirror support cell Secondary mirror
A server farm or server cluster is a collection of computer servers – maintained by an organization to supply server functionality far beyond the capability of a single machine. Server farms consist of thousands of computers which require a large amount of power to run and to keep cool. At the optimum performance level, a server farm has enormous costs associated with it. Server farms have backup servers, which can take over the function of primary servers in the event of a primary-server failure. Server farms are collocated with the network switches and/or routers which enable communication between the different parts of the cluster and the users of the cluster. Server farmers mount the computers, power supplies, related electronics on 19-inch racks in a server room or data center. Server farms are used for cluster computing. Many modern supercomputers comprise giant server farms of high-speed processors connected by either Gigabit Ethernet or custom interconnects such as Infiniband or Myrinet.
Web hosting is a common use of a server farm. Other uses of server farms include scientific simulations and the rendering of 3D computer generated imagery. Server farms are being used instead of or in addition to mainframe computers by large enterprises, although server farms do not yet reach the same reliability levels as mainframes; because of the sheer number of computers in large server farms, the failure of an individual machine is a commonplace event, the management of large server farms needs to take this into account by providing support for redundancy, automatic failover, rapid reconfiguration of the server cluster. The performance of the largest server farms is limited by the performance of the data center's cooling systems and the total electricity cost rather than by the performance of the processors. Computers in server farms run 24/7 and consume large amounts of electricity, for this reason, the critical design parameter for both large and continuous systems tends to be performance per watt rather than cost of peak performance or.
For high availability systems that must run 24/7, there is more attention placed on power saving features such as variable clock-speed and the ability to turn off both computer parts, processor parts, entire computers according to demand without bringing down services. The EEMBC EnergyBench, SPECpower, the Transaction Processing Performance Council TPC-Energy are benchmarks designed to predict performance per watt in a server farm; the power used by each rack of equipment can be measured at the power distribution unit. Some servers include power tracking hardware so the people running the server farm can measure the power used by each server; the power used by the entire server farm may be reported in terms of power usage effectiveness or data center infrastructure efficiency. According to some estimates, for every 100 watts spent on running the servers another 50 watts is needed to cool them. For this reason, the siting of a Server Farm can be as important as processor selection in achieving power efficiency.
Iceland, which has a cold climate all year as well as cheap and carbon-neutral geothermal electricity supply, is building its first major server farm hosting site. Fibre optic cables are being laid from Iceland to North America and Europe to enable companies there to locate their servers in Iceland. Other countries with favorable conditions, such as Canada, Finland and Switzerland, are trying to attract cloud computing data centers. In these countries, heat from the servers can be cheaply vented or used to help heat buildings, thus reducing the energy consumption of conventional heaters. Blade server Compile farm Data center Green computing Render farm Link farm
A transformer is a static electrical device that transfers electrical energy between two or more circuits. A varying current in one coil of the transformer produces a varying magnetic flux, which, in turn, induces a varying electromotive force across a second coil wound around the same core. Electrical energy can be transferred between the two coils, without a metallic connection between the two circuits. Faraday's law of induction discovered in 1831 described the induced voltage effect in any coil due to changing magnetic flux encircled by the coil. Transformers are used for increasing or decreasing the alternating voltages in electric power applications, for coupling the stages of signal processing circuits. Since the invention of the first constant-potential transformer in 1885, transformers have become essential for the transmission and utilization of alternating current electric power. A wide range of transformer designs is encountered in electric power applications. Transformers range in size from RF transformers less than a cubic centimeter in volume, to units weighing hundreds of tons used to interconnect the power grid.
An ideal transformer is a theoretical linear transformer, lossless and coupled. Perfect coupling implies infinitely high core magnetic permeability and winding inductances and zero net magnetomotive force. A varying current in the transformer's primary winding attempts to create a varying magnetic flux in the transformer core, encircled by the secondary winding; this varying flux at the secondary winding induces a varying electromotive force in the secondary winding due to electromagnetic induction and the secondary current so produced creates a flux equal and opposite to that produced by the primary winding, in accordance with Lenz's law. The windings are wound around a core of infinitely high magnetic permeability so that all of the magnetic flux passes through both the primary and secondary windings. With a voltage source connected to the primary winding and load impedance connected to the secondary winding, the transformer currents flow in the indicated directions and the core magnetomotive force cancels to zero.
According to Faraday's law, since the same magnetic flux passes through both the primary and secondary windings in an ideal transformer, a voltage is induced in each winding proportional to its number of windings. Thus, referring to the equations shown in the sidebox at right, according to Faraday's law, we have primary and secondary winding voltages defined by eq. 1 & eq. 2, respectively. The primary EMF is sometimes termed counter EMF; this is in accordance with Lenz's law, which states that induction of EMF always opposes development of any such change in magnetic field. The transformer winding voltage ratio is thus shown to be directly proportional to the winding turns ratio according to eq. 3. However, some sources use the inverse definition. According to the law of conservation of energy, any load impedance connected to the ideal transformer's secondary winding results in conservation of apparent and reactive power consistent with eq. 4. The ideal transformer identity shown in eq. 5 is a reasonable approximation for the typical commercial transformer, with voltage ratio and winding turns ratio both being inversely proportional to the corresponding current ratio.
By Ohm's law and the ideal transformer identity: the secondary circuit load impedance can be expressed as eq. 6 the apparent load impedance referred to the primary circuit is derived in eq. 7 to be equal to the turns ratio squared times the secondary circuit load impedance. The ideal transformer model neglects the following basic linear aspects of real transformers: Core losses, collectively called magnetizing current losses, consisting of Hysteresis losses due to nonlinear magnetic effects in the transformer core, Eddy current losses due to joule heating in the core that are proportional to the square of the transformer's applied voltage. Unlike the ideal model, the windings in a real transformer have non-zero resistances and inductances associated with: Joule losses due to resistance in the primary and secondary windings Leakage flux that escapes from the core and passes through one winding only resulting in primary and secondary reactive impedance. Similar to an inductor, parasitic capacitance and self-resonance phenomenon due to the electric field distribution.
Three kinds of parasitic capacitance are considered and the closed-loop equations are provided Capacitance between adjacent turns in any one layer. However, the capacitance effect can be measured by comparing open-circuit inductance, i.e. the inductance of a primary winding when the secondary circuit is open, to a short-circuit inductance when the secondary winding is shorted. The ideal transformer model assumes that all flux generated by the primary winding links all the turns of every winding, including itself. In practice, some flux traverses paths; such flux is termed leakage flux, results in leakage inductance in series with the mutually coupled transformer windings. Leakage flux results in energy being alternately stored in and discharged from the magnetic fields with each cycle of the power supply, it is not directly a power loss, but results in inferior voltage regulation, causing the secondary voltage not to be directly proportional to the primary voltage under heavy load. Transformers are therefore designed to have low
Primary is the 2002 debut from New Zealand pop punk band Rubicon. The album was peaked at # 16 in the New Zealand pop charts. Seven singles were released off the album, including "Bruce" and "Funny Boy". Album review – NZ Musician magazine Album review – NZ Herald
The Lensman series is a series of science fiction novels by American author Edward Elmer "Doc" Smith. It was a runner-up for the 1966 Hugo award for Best All-Time Series; the series was published in magazines before being collected and reworked into the better-known series of books. The complete series in internal sequence with original publication dates is. Triplanetary First Lensman Galactic Patrol Gray Lensman Second Stage Lensmen Children of the Lens Lensman Sequel The Vortex Blaster Originally, the series consisted of the four novels Galactic Patrol, Gray Lensman, Second Stage Lensmen, Children of the Lens, published between 1937 and 1948 in the magazine Astounding Stories. In 1948, at the suggestion of Lloyd Arthur Eshbach, Smith rewrote his 1934 story Triplanetary to fit in with the Lensman series. First Lensman was written in 1950 to act as a link between Triplanetary and Galactic Patrol and in the years up to 1954, Smith revised the rest of the series to remove inconsistencies between the original Lensman chronology and Triplanetary.
The series begins with Triplanetary, beginning two billion years before the present time and continuing into the near future. The universe has no life-forms aside from the ancient Arisians, few planets besides the Arisians' native world; the peaceful Arisians have foregone physical skills in order to develop contemplative mental power. The underlying assumption for this series, based on theories of stellar evolution extant at the time of the books' writing, is that planets form only and therefore our First and Second Galaxies, with their many billions of planets, are unique; the Eddorians, a dictatorial, power-hungry race, come into our universe from an alien space-time continuum after observing that our galaxy and a sister galaxy are passing through each other. This will result in the formation of billions of planets and the development of life upon some of them. Dominance over these life forms would offer the Eddorians an opportunity to satisfy their lust for power and control. Although the Eddorians have developed mental powers equal to those of the Arisians, they rely instead for the most part on physical power, which came to be exercised on their behalf by a hierarchy of underling races.
They see the many races in the universe, with which the Arisians were intending to build a peaceful civilization, as fodder for their power-drive. The Arisians detect the Eddorians' invasion of our universe and realize that they are too evenly matched for either to destroy the other without being destroyed themselves; the Eddorians do not detect the Arisians, who begin a covert breeding program on every world that can produce intelligent life, with particular emphasis on the four planets Earth, Velantia III, Rigel IV, Palain VII, in the hope of creating a race, capable of destroying the Eddorians. Triplanetary incorporates the early history of that breeding program on Earth, illustrated with the lives of several warriors and soldiers, from ancient times to the discovery of the first interstellar space drive, it adds an additional short novel, transitional to the novel First Lensman. It details some of the interactions and natures of two distinct breeding lines, one bearing some variant of the name "Kinnison", another distinguished by possessing "red-bronze-auburn hair and gold-flecked, tawny eyes".
The two lines do not commingle. The second book, First Lensman, concerns the early formation of the Galactic Patrol and the first Lens, given to First Lensman Virgil Samms of "Tellus". Samms and Roderick Kinnison are members of the two breeding lines and they are both natural leaders, intelligent and capable; the Arisians make it known that if Samms, the head of the Triplanetary Service, visits the Arisian planetary system he will be given the tool he needs to build the Galactic Patrol. That tool is the Lens; the Arisians further promise him that no entity unworthy of the Lens will be permitted to wear it, but that he and his successors will have to discover for themselves most of its abilities. The Lens gives its wearer a variety of mental capabilities, including those needed to enforce the law on alien planets, to bridge the communication gap between different life-forms, it can provide telepathic abilities. It cannot be worn by anyone other than its owner, will kill any other wearer, a brief touch is painful.
Using the Lens as a means to test mental qualities and identify individuals able to help him, Virgil Samms visits races and species in other star systems, recruiting the best of them and forming the nucleus of a Galactic Patrol. Their opponents are discovered to be a widespread civilization based on dominance hierarchies and using organized crime merged with crony capitalism to assume control of new planets; the series contains some of the largest-scale space battles written. Entire worlds are casually destroyed. Huge fleets of spaceships fight bloody wars of attrition. Alien races of two galaxies sort themselv
Overhead power line
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy along large distances. It consists of one or more conductors suspended by poles. Since most of the insulation is provided by air, overhead power lines are the lowest-cost method of power transmission for large quantities of electric energy. Towers for support of the lines are made of wood, steel or aluminum and reinforced plastics; the bare wire conductors on the line are made of aluminum, though some copper wires are used in medium-voltage distribution and low-voltage connections to customer premises. A major goal of overhead power line design is to maintain adequate clearance between energized conductors and the ground so as to prevent dangerous contact with the line, to provide reliable support for the conductors, resilience to storms, ice loads and other potential damage causes. Today overhead lines are operated at voltages exceeding 765,000 volts between conductors. Overhead power transmission lines are classified in the electrical power industry by the range of voltages: Low voltage – less than 1000 volts, used for connection between a residential or small commercial customer and the utility.
Medium voltage -- between 1000 volts and 69 kV, used for distribution in rural areas. High voltage, used for sub-transmission and transmission of bulk quantities of electric power and connection to large consumers. Extra high voltage – from 345 kV, up to about 800 kV, used for long distance high power transmission. Ultra high voltage – higher than 800 kV; the Financial Times reported UHV lines are a "game changer", making a global electricity grid feasible. StateGrid said that compared to conventional lines, UHV enables the transmission of five times more power, over six times the distance. Structures for overhead lines take a variety of shapes depending on the type of line. Structures may be as simple as wood poles directly set in the earth, carrying one or more cross-arm beams to support conductors, or "armless" construction with conductors supported on insulators attached to the side of the pole. Tubular steel poles are used in urban areas. High-voltage lines are carried on lattice-type steel towers or pylons.
For remote areas, aluminum towers may be placed by helicopters. Concrete poles have been used. Poles made of reinforced plastics are available, but their high cost restricts application; each structure must be designed for the loads imposed on it by the conductors. The weight of the conductor must be supported, as well as dynamic loads due to wind and ice accumulation, effects of vibration. Where conductors are in a straight line, towers need only resist the weight since the tension in the conductors balances with no resultant force on the structure. Flexible conductors supported at their ends approximate the form of a catenary, much of the analysis for construction of transmission lines relies on the properties of this form. A large transmission line project may have several types of towers, with "tangent" towers intended for most positions and more constructed towers used for turning the line through an angle, dead-ending a line, or for important river or road crossings. Depending on the design criteria for a particular line, semi-flexible type structures may rely on the weight of the conductors to be balanced on both sides of each tower.
More rigid structures may be intended to remain standing if one or more conductors is broken. Such structures may be installed at intervals in power lines to limit the scale of cascading tower failures. Foundations for tower structures may be large and costly if the ground conditions are poor, such as in wetlands; each structure may be stabilized by the use of guy wires to counteract some of the forces applied by the conductors. Power lines and supporting structures can be a form of visual pollution. In some cases the lines are buried to avoid this, but this "undergrounding" is more expensive and therefore not common. For a single wood utility pole structure, a pole is placed in the ground three crossarms extend from this, either staggered or all to one side; the insulators are attached to the crossarms. For an "H"-type wood pole structure, two poles are placed in the ground a crossbar is placed on top of these, extending to both sides; the insulators are attached in the middle. Lattice tower structures have two common forms.
One has a pyramidal base a vertical section, where three crossarms extend out staggered. The strain insulators are attached to the crossarms. Another has a pyramidal base. On top of this a horizontal truss-like structure is placed. A grounded wire is sometimes strung along the tops of the towers to provide lightning protection. An optical ground wire is a more advanced version with embedded optical fibers for communication. Overhead wire markers can be mounted on the ground wire to meet International Civil Aviation Organization recommendations; some markers include flashing lamps for night-time warning. A single-circuit transmission line carries conductors for only one circuit. For a three-phase system, this implies. A double-circuit transmission line has two circuits. For three