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Topic Review
Technical Support Scam
A technical support scam refers to any class of telephone fraud activities in which a scammer claims to offer a legitimate technical support service, often via cold calls to unsuspecting users. Such calls are mostly targeted at Microsoft Windows users, with the caller often claiming to represent a Microsoft technical support department. In English-speaking countries such as the United States , Canada , United Kingdom , Ireland, Australia and New Zealand, such cold call scams have occurred as early as 2008. and primarily originate from call centers in India . The scammer will typically attempt to get the victim to allow remote access to their computer. After remote access is gained, the scammer relies on confidence tricks, typically involving utilities built into Windows and other software, in order to gain the victim's trust to pay for the supposed "support" services. The scammer will often then steal the victim's credit card account information or persuade the victim to log in to their online banking account to receive a promised refund, only to steal more money, claiming that a secure server is connected and that the scammer cannot see the details. Many schemes involve convincing the victim to purchase expensive gift cards and then to divulge the card information to the scammer.
  • 1.4K
  • 21 Nov 2022
Topic Review
Berlekamp's Root Finding Algorithm
In number theory, Berlekamp's root finding algorithm, also called the Berlekamp–Rabin algorithm, is the probabilistic method of finding roots of polynomials over a field [math]\displaystyle{ \mathbb Z_p }[/math]. The method was discovered by Elwyn Berlekamp in 1970 as an auxiliary to the algorithm for polynomial factorization over finite fields. The algorithm was later modified by Rabin for arbitrary finite fields in 1979. The method was also independently discovered before Berlekamp by other researchers.
  • 1.4K
  • 02 Nov 2022
Topic Review
Localization (Algebra)
In commutative algebra and algebraic geometry, the localization is a formal way to introduce the "denominators" to a given ring or module. That is, it introduces a new ring/module out of an existing one so that it consists of fractions such that the denominator s belongs to a given subset S of R. The basic example is the construction of the ring Q of rational numbers from the ring Z of rational integers. The technique has become fundamental, particularly in algebraic geometry, as it provides a natural link to sheaf theory. In fact, the term localization originates in algebraic geometry: if R is a ring of functions defined on some geometric object (algebraic variety) V, and one wants to study this variety "locally" near a point p, then one considers the set S of all functions which are not zero at p and localizes R with respect to S. The resulting ring R* contains only information about the behavior of V near p. Cf. the example given at local ring. An important related process is completion: one often localizes a ring/module, then completes. In this article, a ring is commutative with unity.
  • 1.4K
  • 29 Nov 2022
Topic Review
NeWS
NeWS (Network extensible Window System) is a discontinued windowing system developed by Sun Microsystems in the mid-1980s. Originally known as "SunDew", its primary authors were James Gosling and David S. H. Rosenthal. The NeWS interpreter was based on PostScript (as was the later Display PostScript, although the two projects were otherwise unrelated) extending it to allow interaction and multiple "contexts" to support windows. Like PostScript, NeWS could be used as a complete programming language, but unlike PostScript, NeWS could be used to make complete interactive programs with mouse support and a GUI.
  • 1.4K
  • 14 Nov 2022
Topic Review
Office Online
Office Online (known before 2014 as Office Web Apps and as of July 2019 as Office) is an online office suite offered by Microsoft, which allows users to create and edit files using lightweight Microsoft Office web apps: Word, Excel, PowerPoint and OneNote. The offering also includes Outlook.com, People, Calendar and OneDrive, all of which are accessible from a unified app switcher. Users can install the on-premises version of this service, called Office Online Server, in private clouds in conjunction with SharePoint, Microsoft Exchange Server and Microsoft Lync Server.
  • 1.3K
  • 25 Nov 2022
Topic Review
MultiOTP
multiOTP is an open source PHP class, a command line tool, and a web interface that can be used to provide an operating-system-independent, strong authentication system. multiOTP is OATH-certified since version 4.1.0 and is developed under the LGPL license. Starting with version 4.3.2.5, multiOTP open source is also available as a virtual appliance - as a standard OVA file, a customized OVA file with open-vm-tools, and also as a Hyper-V downloadable file.Template:Jargon-statement A QR code is generated automatically when printing the user-configuration page.
  • 1.3K
  • 21 Nov 2022
Topic Review
AI: When a Robot Writes a Play
AI: When a Robot Writes a Play (in Czech: AI: Když robot píše hru) is an experimental theatre play, where 90% of its script was automatically generated by artificial intelligence (the GPT-2 language model). The play is in Czech language, but an English version of the script also exists.
  • 1.3K
  • 23 Nov 2022
Topic Review
Ceph
Ceph (pronounced /ˈsɛf/) is an open-source software-defined storage platform that implements object storage on a single distributed computer cluster and provides 3-in-1 interfaces for object-, block- and file-level storage. Ceph aims primarily for completely distributed operation without a single point of failure, scalability to the exabyte level, and to be freely available. Since version 12, Ceph does not rely on other filesystems and can directly manage HDDs and SSDs with its own storage backend BlueStore and can completely self reliantly expose a POSIX filesystem. Ceph replicates data and makes it fault-tolerant, using commodity hardware and Ethernet IP and requiring no specific hardware support. The Ceph’s system offers disaster recovery and data redundancy through techniques such as replication, erasure coding, snapshots and storage cloning. As a result of its design, the system is both self-healing and self-managing, aiming to minimize administration time and other costs. In this way, administrators have a single, consolidated system that avoids silos and collects the storage within a common management framework. Ceph consolidates several storage use cases and improves resource utilization. It also lets an organization deploy servers where needed.
  • 1.3K
  • 14 Oct 2022
Topic Review
Hyperbolic Function
In mathematics, hyperbolic functions are analogs of the ordinary trigonometric functions defined for the hyperbola rather than on the circle: just as the points (cos t, sin t) form a circle with a unit radius, the points (cosh t, sinh t) form the right half of the equilateral hyperbola. Hyperbolic functions occur in the solutions of many linear differential equations (for example, the equation defining a catenary), of some cubic equations, in calculations of angles and distances in hyperbolic geometry, and of Laplace's equation in Cartesian coordinates. Laplace's equations are important in many areas of physics, including electromagnetic theory, heat transfer, fluid dynamics, and special relativity. The basic hyperbolic functions are: from which are derived: corresponding to the derived trigonometric functions. The inverse hyperbolic functions are: The hyperbolic functions take a real argument called a hyperbolic angle. The size of a hyperbolic angle is twice the area of its hyperbolic sector. The hyperbolic functions may be defined in terms of the legs of a right triangle covering this sector. In complex analysis, the hyperbolic functions arise as the imaginary parts of sine and cosine. The hyperbolic sine and the hyperbolic cosine are entire functions. As a result, the other hyperbolic functions are meromorphic in the whole complex plane. By Lindemann–Weierstrass theorem, the hyperbolic functions have a transcendental value for every non-zero algebraic value of the argument. Hyperbolic functions were introduced in the 1760s independently by Vincenzo Riccati and Johann Heinrich Lambert. Riccati used Sc. and Cc. (sinus/cosinus circulare) to refer to circular functions and Sh. and Ch. (sinus/cosinus hyperbolico) to refer to hyperbolic functions. Lambert adopted the names but altered the abbreviations to what they are today. The abbreviations sh, ch, th, cth are also at disposition, their use depending more on personal preference of mathematics of influence than on the local language.
  • 1.3K
  • 10 Nov 2022
Topic Review
1D MPC and Thin-Film Analysis
The development of magnetic photonic crystals (MPC) has been a rapidly evolving research area since the late 1990s. Magneto-optic (MO) materials and the techniques for their characterization have also continually undergone functional and property-related improvements. MPC Optimization is a feature-rich Windows software application designed to enable researchers to analyse the optical and magneto-optical spectral properties of multilayers containing gyrotropic constituents. A set of computational approaches, and a custom software package have been described, designed to enable the design and optimization of 1D magnetic photonic crystals in terms of the achievable combinations of Faraday rotation, transmission, and reflection spectra. 
  • 1.3K
  • 25 Aug 2021
Topic Review
Schwarz Triangle Function
In complex analysis, the Schwarz triangle function or Schwarz s-function is a function that conformally maps the upper half plane to a triangle in the upper half plane having lines or circular arcs for edges. Let πα, πβ, and πγ be the interior angles at the vertices of the triangle. If any of α, β, and γ are greater than zero, then the Schwarz triangle function can be given in terms of hypergeometric functions as: where a = (1−α−β−γ)/2, b = (1−α+β−γ)/2, c = 1−α, a′ = a − c + 1 = (1+α−β−γ)/2, b′ = b − c + 1 = (1+α+β−γ)/2, and c′ = 2 − c = 1 + α. This mapping has singular points at z = 0, 1, and ∞, corresponding to the vertices of the triangle with angles πα, πγ, and πβ respectively. At these singular points, This formula can be derived using the Schwarzian derivative. This function can be used to map the upper half-plane to a spherical triangle on the Riemann sphere if α + β + γ > 1, or a hyperbolic triangle on the Poincaré disk if α + β + γ < 1. When α + β + γ = 1, then the triangle is a Euclidean triangle with straight edges: a = 0, [math]\displaystyle{ _2 F_1 \left(a, b; c; z\right) = 1 }[/math], and the formula reduces to that given by the Schwarz–Christoffel transformation. In the special case of ideal triangles, where all the angles are zero, the triangle function yields the modular lambda function. This function was introduced by H. A. Schwarz as the inverse function of the conformal mapping uniformizing a Schwarz triangle. Applying successive hyperbolic reflections in its sides, such a triangle generates a tessellation of the upper half plane (or the unit disk after composition with the Cayley transform). The conformal mapping of the upper half plane onto the interior of the geodesic triangle generalizes the Schwarz–Christoffel transformation. By the Schwarz reflection principle, the discrete group generated by hyperbolic reflections in the sides of the triangle induces an action on the two dimensional space of solutions. On the orientation-preserving normal subgroup, this two dimensional representation corresponds to the monodromy of the ordinary differential equation and induces a group of Möbius transformations on quotients of solutions. Since the triangle function is the inverse function of such a quotient, it is therefore an automorphic function for this discrete group of Möbius transformations. This is a special case of a general method of Henri Poincaré that associates automorphic forms with ordinary differential equations with regular singular points.
  • 1.3K
  • 13 Oct 2022
Topic Review
Geochemical Modeling
Geochemical modeling is the practice of using chemical thermodynamics, chemical kinetics, or both, to analyze the chemical reactions that affect geologic systems, commonly with the aid of a computer. It is used in high-temperature geochemistry to simulate reactions occurring deep in the Earth's interior, in magma, for instance, or to model low-temperature reactions in aqueous solutions near the Earth's surface, the subject of this article.
  • 1.3K
  • 26 Oct 2022
Topic Review
Weierstrass's Elliptic Functions
In mathematics, Weierstrass's elliptic functions are elliptic functions that take a particularly simple form. They are named for Karl Weierstrass. This class of functions are also referred to as p-functions and they are usually denoted by the symbol ℘. They play an important role in theory of elliptic functions. A ℘-function together with its derivative can be used to parameterize elliptic curves and they generate the field of elliptic functions with respect to a given period lattice.
  • 1.3K
  • 01 Dec 2022
Topic Review
Geologic Modelling
Geologic modelling, geological modelling or geomodelling is the applied science of creating computerized representations of portions of the Earth's crust based on geophysical and geological observations made on and below the Earth surface. A geomodel is the numerical equivalent of a three-dimensional geological map complemented by a description of physical quantities in the domain of interest. Geomodelling is related to the concept of Shared Earth Model; which is a multidisciplinary, interoperable and updatable knowledge base about the subsurface. Geomodelling is commonly used for managing natural resources, identifying natural hazards, and quantifying geological processes, with main applications to oil and gas fields, groundwater aquifers and ore deposits. For example, in the oil and gas industry, realistic geologic models are required as input to reservoir simulator programs, which predict the behavior of the rocks under various hydrocarbon recovery scenarios. A reservoir can only be developed and produced once; therefore, making a mistake by selecting a site with poor conditions for development is tragic and wasteful. Using geological models and reservoir simulation allows reservoir engineers to identify which recovery options offer the safest and most economic, efficient, and effective development plan for a particular reservoir. Geologic modelling is a relatively recent subdiscipline of geology which integrates structural geology, sedimentology, stratigraphy, paleoclimatology, and diagenesis; In 2-dimensions (2D), a geologic formation or unit is represented by a polygon, which can be bounded by faults, unconformities or by its lateral extent, or crop. In geological models a geological unit is bounded by 3-dimensional (3D) triangulated or gridded surfaces. The equivalent to the mapped polygon is the fully enclosed geological unit, using a triangulated mesh. For the purpose of property or fluid modelling these volumes can be separated further into an array of cells, often referred to as voxels (volumetric elements). These 3D grids are the equivalent to 2D grids used to express properties of single surfaces. Geomodelling generally involves the following steps:
  • 1.3K
  • 06 Oct 2022
Topic Review
Adobe Photoshop Version History
This table shows the Adobe Photoshop version history and operating system compatibility in charts, starting with the first versions by independent creators and brothers Thomas and John Knoll in the summer of 1988. The license to distribute the program was purchased by Adobe Systems in September 1988.
  • 1.3K
  • 11 Oct 2022
Topic Review
Blackbird
Blackbird (formerly named FORscene) is an integrated internet video platform, video editing software, covering non-linear editing and publishing for broadcast, web and mobile. Designed by Blackbird plc to allow collaborative editing of video at resolutions of up to 540p and up to 60 frames per second on bandwidths as low as 2MBit/s, it is capable of video logging, reviewing, publishing and hosting through HD and 4K to UHD quality from original sources. The system is implemented as a mobile app for Android and iOS devices, a Java applet and a pure JavaScript web application as part of its user interface. The latter runs on platforms without application installation, codec installation, or machine configuration and has Web 2.0 features. Blackbird won the Royal Television Society's award for Technology in the post-production process in December 2005.
  • 1.3K
  • 02 Nov 2022
Topic Review
2 × 2 Real Matrices
In mathematics, the associative algebra of 2×2 real matrices is denoted by M(2, R). Two matrices p and q in M(2, R) have a sum p + q given by matrix addition. The product matrix p q is formed from the dot product of the rows and columns of its factors through matrix multiplication. For let Then q q* = q* q = (ad − bc) I, where I is the 2×2 identity matrix. The real number ad − bc is called the determinant of q. When ad − bc ≠ 0, q is an invertible matrix, and then The collection of all such invertible matrices constitutes the general linear group GL(2, R). In terms of abstract algebra, M(2, R) with the associated addition and multiplication operations forms a ring, and GL(2, R) is its group of units. M(2, R) is also a four-dimensional vector space, so it is considered an associative algebra. The 2×2 real matrices are in one-one correspondence with the linear mappings of the two-dimensional Cartesian coordinate system into itself by the rule The next section displays M(2,R) is a union of planar cross sections that include a real line. M(2,R) is ring isomorphic to split-quaternions, where there is a similar union but with index sets that are hyperboloids.
  • 1.3K
  • 01 Nov 2022
Topic Review
Perspective Projection Distortion
This page is about graphical perspective projection, specifically about distortion Perspective projection distortion is the mechanism that permits a draftsman or artist to produce linear perspective. It is accomplished by a geometric protocol that exhibits the inevitable distortion of three-dimensional space when “projected," i.e., drawn, on a two-dimensional surface. The words projected/projection here refer to the use of graphics’ lines in the protocol to simulate light ray traces from a Station Point (a supposed observer´s location) to the edges and corners of an object in space, creating thereby or by their extension, an image at the lines’ points of intersection with a Projection Plane. No type of projection can perfectly map the imagery of three dimensional space onto a projection plane because of the image's (mapped on the retina-sphere) undevelopability. This is a distortion of the drawing in itself called perspective projection distortion, and refers to the difference between the drawing and the way the objects depicted on it would look if it was real, but there is another distortion caused by the difference between the location of the supposed observer situated for the drawing process and the location of the real observer of the drawing. These two distortions exist simultaneously. In the special case — and the only instance — in which perspective imagery appears affected only by the perspective projection distortion, the real observer must view the perspective imagery from precisely the supposed station point of the perspective. Real human vision and perspective projection should (unless it is otherwise desired) look the same. The difference should be imperceptible. The base to rate the quality of the perspective projection is the real vision and the difference between them is the perspective projection distortion. Normal human vision should not be considered to present any distortion unless a disturbing factor is involved. Distortion in human vision appears when there is a visual problem involved. The use of lenses can also cause, modify or avoid these distortions. In photography a lens may magnify distortion.
  • 1.3K
  • 21 Oct 2022
Topic Review
Stencil Code
Stencil codes are a class of iterative kernels which update array elements according to some fixed pattern, called a stencil. They are most commonly found in the codes of computer simulations, e.g. for computational fluid dynamics in the context of scientific and engineering applications. Other notable examples include solving partial differential equations, the Jacobi kernel, the Gauss–Seidel method, image processing and cellular automata. The regular structure of the arrays sets stencil codes apart from other modeling methods such as the Finite element method. Most finite difference codes which operate on regular grids can be formulated as stencil codes.
  • 1.3K
  • 16 Nov 2022
Topic Review
Weights and Measures Acts (UK)
Weights and measures acts are acts of the British Parliament determining the regulation of weights and measures. It also refers to similar royal and parliamentary acts of the Kingdoms of England and Scotland and the medieval Welsh states. The earliest of these were originally untitled but were given descriptive glosses or titles based upon the monarch under whose reign they were promulgated. Several omnibus modern acts are entitled the Weights and Measures Act and are distinguished by the year of their enactment. There have been many laws concerned with weights and measures in the United Kingdom or parts of it over the last 1000 or so years. The acts may catalogue lawful weights and measures, prescribe the mechanism for inspection and enforcement of the use of such weights and measures and may set out circumstances under which they may be amended. Modern legislation may, in addition to specific requirements, set out circumstances under which the incumbent minister may amend the legislation by means of statutory instruments. Prior to the Weights and Measures Act 1985, weights and measures acts were only concerned with trade law where the weight or size of the goods being traded was important. The 1985 act, however, had a broader scope, encompassing all aspects covered by the European Economic Community (EEC) European Commission directive 80/181/EEC. As of 25 April 2012, the current primary legislation in the United Kingdom is the 1985 Act, which was last amended by statutory instrument in 2011. Statutory instruments made under the authority of the Act do not amend the Act per se, but regulate particular areas covered by the Act. The Act is currently enforced by the 200 Trading Standards Offices managed by local authorities around the country. Definitions of units of measurements and the technical equipment relating to weights and measures are provided by the National Measurement Office, an agency of the Department for Business, Innovation and Skills.
  • 1.3K
  • 14 Oct 2022
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