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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Java Persistence API
The Java Persistence API (JPA), in 2019 renamed to Jakarta Persistence, is a Java application programming interface specification that describes the management of relational data in applications using Java Platform, Standard Edition and Java Platform, Enterprise Edition/Jakarta EE. Persistence in this context covers three areas: The reference implementation for JPA is EclipseLink.
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  • 14 Oct 2022
Topic Review
IQ and the Wealth of Nations
IQ and the Wealth of Nations is a 2002 book by psychologist Richard Lynn and political scientist Tatu Vanhanen. The authors argue that differences in national income (in the form of per capita gross domestic product) are correlated with differences in the average national intelligence quotient (IQ). They further argue that differences in average national IQs constitute one important factor, but not the only one, contributing to differences in national wealth and rates of economic growth. The book has drawn widespread criticism from other academics. Critiques have included questioning of the methodology used, the incompleteness of the data, and the conclusions drawn from the analysis. The 2006 book IQ and Global Inequality is a follow-up to IQ and the Wealth of Nations by the same authors.
  • 9.8K
  • 14 Oct 2022
Topic Review
Support Vector Machine
In machine learning, support-vector machines (SVMs, also support-vector networks) are supervised learning models with associated learning algorithms that analyze data used for classification and regression analysis. The Support Vector Machine (SVM) algorithm is a popular machine learning tool that offers solutions for both classification and regression problems. Developed at AT&T Bell Laboratories by Vapnik with colleagues (Boser et al., 1992, Guyon et al., 1993, Vapnik et al., 1997), it presents one of the most robust prediction methods, based on the statistical learning framework or VC theory proposed by Vapnik and Chervonekis (1974) and Vapnik (1982, 1995). Given a set of training examples, each marked as belonging to one or the other of two categories, an SVM training algorithm builds a model that assigns new examples to one category or the other, making it a non-probabilistic binary linear classifier (although methods such as Platt scaling exist to use SVM in a probabilistic classification setting). An SVM model is a representation of the examples as points in space, mapped so that the examples of the separate categories are divided by a clear gap that is as wide as possible. New examples are then mapped into that same space and predicted to belong to a category based on the side of the gap on which they fall. In addition to performing linear classification, SVMs can efficiently perform a non-linear classification using what is called the kernel trick, implicitly mapping their inputs into high-dimensional feature spaces. When data are unlabelled, supervised learning is not possible, and an unsupervised learning approach is required, which attempts to find natural clustering of the data to groups, and then map new data to these formed groups. The support-vector clustering algorithm, created by Hava Siegelmann and Vladimir Vapnik, applies the statistics of support vectors, developed in the support vector machines algorithm, to categorize unlabeled data, and is one of the most widely used clustering algorithms in industrial applications.
  • 7.5K
  • 14 Oct 2022
Topic Review
Climate Fiction
Climate fiction (sometimes shortened cli-fi) is literature that deals with climate change and global warming. Not necessarily speculative in nature, works may take place in the world as we know it or in the near future. University courses on literature and environmental issues may include climate change fiction in their syllabi. This body of literature has been discussed by a variety of publications, including The New York Times , The Guardian , and Dissent magazine, among other international media outlets.
  • 3.9K
  • 14 Oct 2022
Topic Review
Five Hundred Meter Aperture Spherical Telescope
The Five-hundred-meter Aperture Spherical radio Telescope (FAST; Chinese: 五百米口径球面射电望远镜), nicknamed Tianyan (天眼, lit. "Heavenly Eye" or "The Eye of Heaven") is a radio telescope located in the Dawodang depression (大窝凼洼地), a natural basin in Pingtang County, Guizhou Province, southwest China. It consists of a fixed 500 m (1,600 ft) diameter dish constructed in a natural depression in the landscape. It is the world's largest filled-aperture radio telescope, and the second-largest single-dish aperture after the sparsely-filled RATAN-600 in Russia. It has a novel design, using an active surface made of metal panels that can be tilted by a computer to help change the focus to different areas of the sky. The cabin containing the feed antenna suspended on cables above the dish is also moved using a digitally-controlled winch by the computer control system to steer the instrument to receive from different directions. Construction on the FAST project began in 2011 and it achieved first light in September 2016. It is currently undergoing testing and commissioning. It observes at wavelengths of 10 cm to 4.3 m.:11 The telescope made its first discovery of two new pulsars in August 2017, barely one year after its first light. The new pulsars PSR J1859-01 and PSR J1931-02, which are also referred to as FAST pulsar #1 and #2 (FP1 and FP2), were detected on 22 and 25 August and are 16,000 and 4,100 light years away, respectively. They were independently confirmed by the Parkes Observatory in Australia on 10 September. The telescope had discovered 44 new pulsars by September, 2018.
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  • 14 Oct 2022
Topic Review
Validation in the Clinical Theory of Psychoanalysis
Validation in the Clinical Theory of Psychoanalysis: A Study in the Philosophy of Psychoanalysis is a 1993 book about psychoanalysis, and related topics such as the nature and effectiveness of the placebo and its role in psychiatry and medicine, by the philosopher Adolf Grünbaum. The book, in part a sequel to Grünbaum's earlier The Foundations of Psychoanalysis (1984) and a response to analytic critics of that work, received both positive reviews and more mixed assessments. Reviewers found it an important work about both psychoanalysis and the concept of the placebo, but noted that Grünbaum's writing style made it difficult to read.
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  • 14 Oct 2022
Topic Review
Distance Measuring Equipment (Aviation)
In aviation, distance measuring equipment (DME) is a radio navigation technology that measures the slant range (distance) between an aircraft and a ground station by timing the propagation delay of radio signals in the frequency band between 960 and 1215 megahertz (MHz). Line-of-visibility between the aircraft and ground station is required. An interrogator (airborne) initiates an exchange by transmitting a pulse pair, on an assigned 'channel', to the transponder ground station. The channel assignment specifies the carrier frequency and the spacing between the pulses. After a known delay, the transponder replies by transmitting a pulse pair on a frequency that is offset from the interrogation frequency by 63 MHz and having specified separation. DME systems are used worldwide, using standards set by the International Civil Aviation Organization (ICAO), RTCA, the European Union Aviation Safety Agency (EASA) and other bodies. Some countries require that aircraft operating under instrument flight rules (IFR) be equipped with a DME interrogator; in others, a DME interrogator is only required for conducting certain operations. While stand-alone DME transponders are permitted, DME transponders are usually paired with an azimuth guidance system to provide aircraft with a two-dimensional navigation capability. A common combination is a DME colocated with a VHF omnidirectional range (VOR) transmitter in a single ground station. When this occurs, the frequencies of the VOR and DME equipment are paired. Such a configuration enables an aircraft to determine its azimuth angle and distance from the station. A VORTAC (a VOR co-located with a TACAN) installation provides the same capabilities to civil aircraft but also provides 2-D navigation capabilities to military aircraft. Low-power DME transponders are also associated with some instrument landing system (ILS), ILS localizer and microwave landing system (MLS) installations. In those situations, the DME transponder frequency/pulse spacing is also paired with the ILS, LOC or MLS frequency. ICAO characterizes DME transmissions as ultra high frequency (UHF). The term L-band is also used. Developed in Australia, DME was invented by James "Gerry" Gerrand under the supervision of Edward George "Taffy" Bowen while employed as Chief of the Division of Radiophysics of the Commonwealth Scientific and Industrial Research Organisation (CSIRO). Another engineered version of the system was deployed by Amalgamated Wireless Australasia Limited in the early 1950s operating in the 200 MHz VHF band. This Australian domestic version was referred to by the Federal Department of Civil Aviation as DME(D) (or DME Domestic), and the later international version adopted by ICAO as DME(I). DME is similar in principle to secondary radar ranging function, except the roles of the equipment in the aircraft and on the ground are reversed. DME was a post-war development based on the identification friend or foe (IFF) systems of World War II. To maintain compatibility, DME is functionally identical to the distance measuring component of TACAN.
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  • 14 Oct 2022
Topic Review
Hyracoidea
Hyraxes (from grc ὕραξ (Script error: No such module "Ancient Greek".) 'shrewmouse'), also called dassies, are small, thickset, herbivorous mammals in the order Hyracoidea. Hyraxes are well-furred, rotund animals with short tails. Typically, they measure between 30 and 70 cm (12 and 28 in) long and weigh between 2 and 5 kg (4 and 11 lb). They are superficially similar to pikas and marmots, but are more closely related to elephants and sea cows. Hyraxes have a life span from 9 to 14 years. Five extant species are recognised: the rock hyrax (Procavia capensis) and the yellow-spotted rock hyrax (Heterohyrax brucei), which both live on rock outcrops, including cliffs in Ethiopia and isolated granite outcrops called koppies in southern Africa; the western tree hyrax (Dendrohyrax dorsalis), southern tree hyrax (D. arboreus), and eastern tree hyrax (D. validus). Their distribution is limited to Africa, except for P. capensis, which is also found in the Middle East.
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  • 14 Oct 2022
Topic Review
Racing Shell
In watercraft, a racing shell (also referred to as just a fine boat (UK) or just shell) is an extremely narrow, and often comparatively long, rowing boat specifically designed for racing or exercise. It is outfitted with long oars, outriggers to hold the oarlocks away from the boat, and sliding seats. The boat's long length and semicircular cross-section reduce drag to a minimum. This makes the boat both fast and unstable. It must be balanced by the rowers to avoid tipping. Being able to balance – or "set" – the boat while putting maximum effort into the oars is therefore an essential skill of sport rowing.
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  • 14 Oct 2022
Topic Review
Charge
In physics, a charge is any of many different quantities, such as the electric charge in electromagnetism or the color charge in quantum chromodynamics. Charges correspond to the time-invariant generators of a symmetry group, and specifically, to the generators that commute with the Hamiltonian. Charges are often denoted by the letter Q, and so the invariance of the charge corresponds to the vanishing commutator [math]\displaystyle{ [Q,H]=0 }[/math], where H is the Hamiltonian. Thus, charges are associated with conserved quantum numbers; these are the eigenvalues q of the generator Q.
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  • 14 Oct 2022
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