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Topic Review

Triangle Center

In geometry, a triangle center (or triangle centre) is a point in the plane that is in some sense a center of a triangle akin to the centers of squares and circles, that is, a point that is in the middle of the figure by some measure. For example the centroid, circumcenter, incenter and orthocenter were familiar to the ancient Greeks, and can be obtained by simple constructions. Each of these classical centers has the property that it is invariant (more precisely equivariant) under similarity transformations. In other words, for any triangle and any similarity transformation (such as a rotation, reflection, dilation, or translation), the center of the transformed triangle is the same point as the transformed center of the original triangle. This invariance is the defining property of a triangle center. It rules out other well-known points such as the Brocard points which are not invariant under reflection and so fail to qualify as triangle centers. All centers of an equilateral triangle coincide at its centroid, but they generally differ from each other on scalene triangles. The definitions and properties of thousands of triangle centers have been collected in the Encyclopedia of Triangle Centers.

3.3K
31 Oct 2022

Topic Review

In library and information science, cataloging (US) or cataloguing (UK) is the process of creating metadata representing information resources, such as books, sound recordings, moving images, etc. Cataloging provides information such as creator names, titles, and subject terms that describe resources, typically through the creation of bibliographic records. The records serve as surrogates for the stored information resources. Since the 1970s these metadata are in machine-readable form and are indexed by information retrieval tools, such as bibliographic databases or search engines. While typically the cataloging process results in the production of library catalogs, it also produces other types of discovery tools for documents and collections. Bibliographic control provides the philosophical basis of cataloging, defining the rules for sufficiently describing information resources to enable users to find and select the most appropriate resource. A cataloger is an individual responsible for the processes of description, subject analysis, classification, and authority control of library materials. Catalogers serve as the "foundation of all library service, as they are the ones who organize information in such a way as to make it easily accessible".

3.3K
22 Nov 2022

Topic Review

History of the Portable Document Format (PDF)

The Portable Document Format was created in the early 1990s by Adobe Systems, introduced at the Windows and OS|2 Conference in January 1993 and remained a proprietary format until it was released as an open standard in 2008. Since then, it is under control of International Organization for Standardization Committee of volunteer industry experts. PDF was developed to share documents, including text formatting and inline images, among computer users of disparate platforms who may not have access to mutually-compatible application software.It was created by a research and developement team called Camelot, led by Adobe's co-founder John Warnock. PDF was one among a number of competing formats such as DjVu, Envoy, Common Ground Digital Paper, Farallon Replica and even Adobe's own PostScript format. In those early years before the rise of the World Wide Web and HTML documents, PDF was popular mainly in desktop publishing workflows. PDF's adoption in the early days of the format's history was slow. Adobe Acrobat, Adobe's suite for reading and creating PDF files, was not freely available; early versions of PDF had no support for external hyperlinks, reducing its usefulness on the Internet; the larger size of a PDF document compared to plain text required longer download times over the slower modems common at the time; and rendering PDF files was slow on the less powerful machines of the day. Adobe distributed its Adobe Reader (now Acrobat Reader) program free of charge from version 2.0 onwards, and continued supporting the original PDF, which eventually became the de facto standard for fixed-format electronic documents. In 2008 Adobe Systems' PDF Reference 1.7 became ISO 32000:1:2008. Thereafter, further development of PDF (including PDF 2.0) is conducted by ISO's TC 171 SC 2 WG 8 with the participation of Adobe Systems and other subject matter experts.

3.3K
14 Oct 2022

Topic Review

Kodi (formerly XBMC) is a free and open-source media player software application developed by the XBMC Foundation, a non-profit technology consortium. Kodi is available for multiple operating systems and hardware platforms, with a software 10-foot user interface for use with televisions and remote controls. It allows users to play and view most streaming media, such as videos, music, podcasts, and videos from the Internet, as well as all common digital media files from local and network storage media. It is a multi-platform home-theater PC (HTPC) application. Kodi is customizable: skins can change its appearance, and plug-ins allow users to access streaming media content via online services such as Amazon Prime Instant Video, Crackle, Pandora Internet Radio, Rhapsody, Spotify, and YouTube. The later versions also have a personal video-recorder (PVR) graphical front end for receiving live television with electronic program guide (EPG) and high-definition digital video recorder (DVR) support. The software was created in 2002 as an independently developed homebrew media player application named Xbox Media Player for the first-generation Xbox game console, changing its name in 2004 to Xbox Media Center (abbreviated as XBMC, which was adopted as the official name in 2008) and was later made available under the name XBMC as a native application for Android, Linux, BSD, macOS, iOS/tvOS, and Microsoft Windows-based operating systems. Because of its open source and cross-platform nature, with its core code written in C++, modified versions of Kodi-XBMC together with JeOS have been used as a software appliance suite or software framework in a variety of devices, including smart TVs, set-top boxes, digital signage, hotel television systems, network connected media players and embedded systems based on armhf platforms like Raspberry Pi. Derivative applications such as MediaPortal and Plex have been spun off from XBMC or Kodi, as well as just enough operating systems like LibreELEC. Kodi has attracted negative attention due to the availability of third-party plug-ins for the software that facilitate unauthorized access to copyrighted media content, as well as "fully loaded" digital media players that are pre-loaded with such add-ons; The XBMC Foundation has not endorsed any of these uses, and has taken steps to disassociate the Kodi project from these add-ons, including threatening legal action against those using its trademarks to promote them.

3.3K
10 Oct 2022

Topic Review

Food science is the basic science and applied science of food; its scope starts at overlap with agricultural science and nutritional science and leads through the scientific aspects of food safety and food processing, informing the development of food technology. Food science brings together multiple scientific disciplines. It incorporates concepts from fields such as chemistry, physics, physiology, microbiology, and biochemistry. Food technology incorporates concepts from chemical engineering, for example. Activities of food scientists include the development of new food products, design of processes to produce these foods, choice of packaging materials, shelf-life studies, sensory evaluation of products using survey panels or potential consumers, as well as microbiological and chemical testing. Food scientists may study more fundamental phenomena that are directly linked to the production of food products and its properties.

3.3K
12 Oct 2022

Topic Review

Social hacking describes the act of attempting to manipulate outcomes of social behaviour through orchestrated actions. The general function of social hacking is to gain access to restricted information or to a physical space without proper permission. Most often, social hacking attacks are achieved by impersonating an individual or group who is directly or indirectly known to the victims or by representing an individual or group in a position of authority. This is done through pre-meditated research and planning to gain victims’ confidence. Social hackers take great measures to present overtones of familiarity and trustworthiness to elicit confidential or personal information. Social hacking is most commonly associated as a component of “social engineering”. Although the practice involves exercising control over human behaviour rather than computers, the term "social hacking" is also used in reference to online behaviour and increasingly, social media activity. The technique can be used in multiple ways that affect public perception and conversely, increase public awareness of social hacking activity. However, while awareness helps reduce the volume of hacks being carried out, technology has allowed for attack tools to become more sophisticated.

3.3K
20 Oct 2022

Topic Review

FAO Country Profiles

The FAO Country Profiles are a multilingual web portal which repackages the Food and Agriculture Organization of the United Nations (FAO) information archive on its global activities in agriculture and food security in a single area and catalogues it exclusively by country and thematic areas. The organization aims to offer decision-makers, researchers and project formulators around the world a fast and reliable way to access country-specific information on national food security situations without the need to search individual databases and systems. It aids FAO's database by providing a simple interface containing interactive maps and charts.

3.3K
09 Nov 2022

Topic Review

Intersection (Euclidean Geometry)

In geometry, an intersection is a point, line, or curve common to two or more objects (such as lines, curves, planes, and surfaces). The simplest case in Euclidean geometry is the intersection of two distinct lines, which either is one point or does not exist if the lines are parallel. Determination of the intersection of flats – linear geometric objects embedded in a higher-dimensional space – is a simple task of linear algebra, namely the solution of a system of linear equations. In general the determination of an intersection leads to non-linear equations, which can be solved numerically, for example using Newton iteration. Intersection problems between a line and a conic section (circle, ellipse, parabola, etc.) or a quadric (sphere, cylinder, hyperboloid, etc.) lead to quadratic equations that can be easily solved. Intersections between quadrics lead to quartic equations that can be solved algebraically.

3.3K
31 Oct 2022

Topic Review

In Vapnik–Chervonenkis theory, the VC dimension (for Vapnik–Chervonenkis dimension) is a measure of the capacity (complexity, expressive power, richness, or flexibility) of a space of functions that can be learned by a statistical classification algorithm. It is defined as the cardinality of the largest set of points that the algorithm can shatter. It was originally defined by Vladimir Vapnik and Alexey Chervonenkis. Formally, the capacity of a classification model is related to how complicated it can be. For example, consider the thresholding of a high-degree polynomial: if the polynomial evaluates above zero, that point is classified as positive, otherwise as negative. A high-degree polynomial can be wiggly, so it can fit a given set of training points well. But one can expect that the classifier will make errors on other points, because it is too wiggly. Such a polynomial has a high capacity. A much simpler alternative is to threshold a linear function. This function may not fit the training set well, because it has a low capacity. This notion of capacity is made rigorous below.

3.3K
04 Nov 2022

Topic Review

FreeNAS is a free and open-source network-attached storage (NAS) operating system based on FreeBSD and the OpenZFS file system. It is licensed under the terms of the BSD License and runs on commodity x86-64 hardware. FreeNAS supports Windows, macOS and Unix clients and various virtualization hosts such as XenServer and VMware using the SMB, AFP, NFS, iSCSI, SSH, rsync and FTP/TFTP protocols. Advanced FreeNAS features include full-disk encryption and a plug-in architecture for third-party software.

3.2K
27 Oct 2022

Topic Review

Root Name Server

A root name server is a name server for the root zone of the Domain Name System (DNS) of the Internet. It directly answers requests for records in the root zone and answers other requests by returning a list of the authoritative name servers for the appropriate top-level domain (TLD). The root name servers are a critical part of the Internet infrastructure because they are the first step in translating (resolving) human readable host names into IP addresses that are used in communication between Internet hosts. A combination of limits in the DNS and certain protocols, namely the practical size of unfragmented User Datagram Protocol (UDP) packets, resulted in a decision to limit the number of root servers to thirteen server addresses. The use of anycast addressing permits the actual number of root server instances to be much larger, and is 1,086 (As of July 2020).

3.2K
03 Nov 2022

Topic Review

Samsung Knox is a proprietary security and management framework pre-installed on most Samsung mobile devices. Its primary purpose is to provide organizations with a toolset for managing work devices, such as employee mobile phones or interactive kiosks. Knox provides more granular control over the standard work profile to manage capabilities found only on Samsung devices. Knox's features fall within three categories: data security, device manageability, and VPN capability. Knox also provides web-based services for organizations to manage their devices. Organizations can customize their managed mobile devices by configuring various functions, including pre-loaded applications, settings, boot-up animations, home screens, and lock screens. As of December 2020, organizations can use specific Samsung mobile device cameras as barcode scanners, using Knox services to capture and analyze the data.

3.2K
17 Nov 2022

Topic Review

CHCP (DOS Command)

This article presents a list of commands used by DOS operating systems, especially as used on x86-based IBM PC compatibles (PCs). Other DOS operating systems are not part of the scope of this list. In DOS, many standard system commands were provided for common tasks such as listing files on a disk or moving files. Some commands were built into the command interpreter, others existed as external commands on disk. Over the several generations of DOS, commands were added for the additional functions of the operating system. In the current Microsoft Windows operating system, a text-mode command prompt window, cmd.exe, can still be used.

3.2K
30 Nov 2022

Topic Review

Moho (Anime Studio)

Moho is a proprietary vector-based 2D animation software distributed by Smith Micro Software. Moho, (formerly known as Anime Studio), was originally distributed by LostMarble, and then by e frontier. Smith Micro Software has distributed Anime Studio since November 2007. The software comes in two different versions, Moho Debut and Moho Pro. The first being restricted in terms of length and image size, as well as not containing all of the functions of the Pro version. Anime Studio is available for Windows and Macintosh operating systems in English, German, Japanese and Spanish (Since version 9.2). Moho Pro no longer supports the Linux platform.

3.2K
11 Nov 2022

Topic Review

IrfanView (/ˈɪərfænvjuː/) is an image viewer, editor, organiser and converter program for Microsoft Windows. It can also play video and audio files, and has some image creation and painting capabilities. IrfanView is free for non-commercial use; commercial use requires paid registration. It is noted for its small size, speed, ease of use, and ability to handle a wide variety of graphic file formats. It was first released in 1996. IrfanView is named after its creator, Irfan Škiljan, from Jajce, Bosnia and Herzegovina, living in Vienna. The current version of IrfanView, 4.58, works under all versions of Windows from Windows 2000 SP4 to Windows 10, while all older versions are compatible with Windows 95/98/ME and can also be run in Linux under Wine and in macOS using WineBottler.

3.2K
30 Oct 2022

Topic Review

Komi (コミ) in the game of Go are points added to the score of the player with the white stones as compensation for playing second. Black's first move advantage is generally considered to equal somewhere between 5 and 7 points by the end of the game. Standard komi is 6.5 points under the Japanese and Korean rules; under Chinese, Ing and AGA rules standard komi is 7.5 points; under New Zealand rules standard komi is 7 points. Komi typically applies only to games where both players are evenly ranked. In the case of a one-rank difference, the stronger player will typically play with the white stones and players often agree on a simple 0.5-point komi to break a tie ("jigo") in favour of white, or no komi at all. Komidashi (コミ出し) is the more complete Japanese language term. The Chinese term is 贴目 (tiē mù) and the Korean term is Deom (덤).

3.2K
14 Nov 2022

Topic Review

Turn (Geometry)

A turn is a unit of plane angle measurement equal to 2π radians, 360 degrees or 400 gradians. A turn is also referred to as a cycle (abbreviated cyc), revolution (abbreviated rev), complete rotation (abbreviated rot) or full circle. Subdivisions of a turn include half turns, quarter turns, centiturns, milliturns, points, etc.

3.2K
22 Nov 2022

Topic Review

Matching Theory (Economics)

In economics, matching theory, also known as search and matching theory, is a mathematical framework attempting to describe the formation of mutually beneficial relationships over time. Matching theory has been especially influential in labor economics, where it has been used to describe the formation of new jobs, as well as to describe other human relationships like marriage. Matching theory evolved from an earlier framework called 'search theory'. Where search theory studies the microeconomic decision of an individual searcher, matching theory studies the macroeconomic outcome when one or more types of searchers interact. It offers a way of modeling markets in which frictions prevent instantaneous adjustment of the level of economic activity. Among other applications, it has been used as a framework for studying frictional unemployment. One of the founders of matching theory is Dale T. Mortensen of Northwestern University. A textbook treatment of the matching approach to labor markets is Christopher A. Pissarides' book Equilibrium Unemployment Theory. Mortensen and Pissarides, together with Peter A. Diamond, were awarded the 2010 Nobel Prize in Economics for 'fundamental contributions to search and matching theory'.

3.2K
09 Nov 2022

Topic Review

A lozenge ( /ˈlɒz.ɪndʒ/), ◊ – often referred to as a diamond – is a form of rhombus. The definition of lozenge is not strictly fixed, and it is sometimes used simply as a synonym (from the French: losange) for rhombus. Most often, though, lozenge refers to a thin rhombus—a rhombus with two acute and two obtuse angles, especially one with acute angles of 45°. The lozenge shape is often used in parquetry (with acute angles that are 360°/n with n being an integer higher than 4, because they can be used to form a set of tiles of the same shape and size, reusable to cover the plane in various geometric patterns as the result of a tiling process called tessellation in mathematics) and as decoration on ceramics, silverware and textiles. It also features in heraldry and playing cards.

3.2K
29 Nov 2022

Topic Review

Science, Technology, Engineering, and Mathematics

Science, technology, engineering, and mathematics (STEM) is a broad term used to group together these academic disciplines. This term is typically used to address an education policy or curriculum choices in schools. It has implications for workforce development, national security concerns (as a shortage of STEM-educated citizens can reduce effectiveness in this area) and immigration policy. There is no universal agreement on which disciplines are included in STEM; in particular whether or not the science in STEM includes social sciences, such as psychology, sociology, economics, and political science. In the United States, these are typically included by organizations such as the National Science Foundation (NSF). The National Science Foundation deals with all matters concerning science and new discoveries in science as it affects development, research, and innovations, the Department of Labor's O*Net online database for job seekers, and the Department of Homeland Security. In the United Kingdom, the social sciences are categorized separately and are instead grouped together with humanities and arts to form another counterpart acronym HASS (Humanities, Arts, and Social Sciences), rebranded in 2020 as SHAPE (Social Sciences, Humanities and the Arts for People and the Economy).

3.2K
14 Nov 2022

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