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Topic Review
Calendar of 13 Months
Has anyone of us missed an event because he was confused between days and dates? Do we really remember the date of any day if we do not have a calendar? Is the current Gregorian Calendar efficient enough for use, and does it really facilitate our life or make it more complicated?  Have you ever thought about a much simpler way to calculate days and dates in a year? All these questions are answered in this article, in which the author proposes an original calendar that might facilitate our lives if we can apply it.
  • 237.3K
  • 12 Jan 2023
Topic Review
Plus-Minus Sign
The plus-minus sign (±) is a mathematical symbol with multiple meanings. The sign is normally pronounced "plus or minus". In mathematics, it generally indicates a choice of exactly two possible values, one of which is the negation of the other. In experimental sciences, the sign commonly indicates the confidence interval or error in a measurement, often the standard deviation or standard error. The sign may also represent an inclusive range of values that a reading might have. In engineering the sign indicates the tolerance, which is the range of values that are considered to be acceptable, safe, or which comply with some standard, or with a contract. In botany it is used in morphological descriptions to notate "more or less". In chemistry the sign is used to indicate a racemic mixture. In chess, the sign indicates a clear advantage for the white player; the complementary sign ∓ indicates the same advantage for the black player.
  • 93.8K
  • 23 Apr 2023
Topic Review
Planck Length
In physics, the Planck length, denoted ℓP, is a unit of length in the system of Planck units that was originally proposed by physicist Max Planck, equal to 1.616255(18)×10−35 m.[note 1] The Planck length can be defined from three fundamental physical constants: the speed of light, the Planck constant, and the gravitational constant. It is also the reduced Compton wavelength of a particle with Planck mass. Regardless of whether it represents some fundamental limit to the universe, it is a useful unit in theoretical physics.
  • 24.4K
  • 18 Nov 2022
Topic Review
Photo Manipulation
Photo manipulation involves transforming or altering a photograph using various methods and techniques to achieve desired results. Some photo manipulations are considered skillful artwork while others are frowned upon as unethical practices, especially when used to deceive the public. Other examples include being used for political propaganda, or to make a product or person look better, or simply for entertainment purposes or harmless pranks. Depending on the application and intent, some photo manipulations are considered an art form because it involves the creation of unique images and in some instances, signature expressions of art by photographic artists. For example, Ansel Adams employed some of the more common manipulations using darkroom exposure techniques, burning (darkening) and dodging (lightening) a photograph. Other examples of photo manipulation include retouching photographs using ink or paint, airbrushing, double exposure, piecing photos or negatives together in the darkroom, scratching instant films, or through the use of software-based manipulation tools applied to digital images. There are a number of software applications available for digital image manipulation, ranging from professional applications to very basic imaging software for casual users.
  • 23.4K
  • 24 Oct 2022
Topic Review
Sigma-Algebra
In mathematical analysis and in probability theory, a σ-algebra (also σ-field) on a set X is a collection Σ of subsets of X that includes the empty subset, is closed under complement, and is closed under countable unions and countable intersections. The pair (X, Σ) is called a measurable space or Borel space. A σ-algebra is a type of algebra of sets. An algebra of sets needs only to be closed under the union or intersection of finitely many subsets, which is a weaker condition. The main use of σ-algebras is in the definition of measures; specifically, the collection of those subsets for which a given measure is defined is necessarily a σ-algebra. This concept is important in mathematical analysis as the foundation for Lebesgue integration, and in probability theory, where it is interpreted as the collection of events which can be assigned probabilities. Also, in probability, σ-algebras are pivotal in the definition of conditional expectation. In statistics, (sub) σ-algebras are needed for the formal mathematical definition of a sufficient statistic, particularly when the statistic is a function or a random process and the notion of conditional density is not applicable. If X = {a, b, c, d}, one possible σ-algebra on X is Σ = { ∅, {a, b}, {c, d}, {a, b, c, d} }, where ∅ is the empty set. In general, a finite algebra is always a σ-algebra. If {A1, A2, A3, …} is a countable partition of X then the collection of all unions of sets in the partition (including the empty set) is a σ-algebra. A more useful example is the set of subsets of the real line formed by starting with all open intervals and adding in all countable unions, countable intersections, and relative complements and continuing this process (by transfinite iteration through all countable ordinals) until the relevant closure properties are achieved (a construction known as the Borel hierarchy).
  • 12.4K
  • 01 Dec 2022
Topic Review
Snakes and Ladders
Snakes and Ladders, known originally as Moksha Patam, is an ancient Indian board game for two or more players regarded today as a worldwide classic. It is played on a game board with numbered, gridded squares. A number of "ladders" and "snakes" are pictured on the board, each connecting two specific board squares. The object of the game is to navigate one's game piece, according to die rolls, from the start (bottom square) to the finish (top square), helped by climbing ladders but hindered by falling down snakes. The game is a simple race based on sheer luck, and it is popular with young children. The historic version had its roots in morality lessons, on which a player's progression up the board represented a life journey complicated by virtues (ladders) and vices (snakes). The game is also sold under other names such as Chutes and Ladders, Bible Ups and Downs, etc., some with a morality motif; a morality Chutes and Ladders was published by Milton Bradley starting from 1943.
  • 12.1K
  • 09 Oct 2022
Topic Review
Vocaloid
Vocaloid is a singing voice synthesizer and the first engine released in the Vocaloid series. It was succeeded by Vocaloid 2. This version was made to be able to sing both English and Japanese.
  • 11.1K
  • 17 Oct 2022
Topic Review
Social Integration
Social integration is the process during which newcomers or minorities are incorporated into the social structure of the host society. Social integration, together with economic integration and identity integration, are three main dimensions of a newcomers' experiences in the society that is receiving them. A higher extent of social integration contributes to a closer social distance between groups and more consistent values and practices. Bringing together various ethnic groups irrespective of language, caste, creed, etc., without losing one's identity. It gives access to all areas of community life and eliminates segregation. In a broader view, social integration is a dynamic and structured process in which all members participate in dialogue to achieve and maintain peaceful social relations. Social integration does not mean forced assimilation. Social integration is focused on the need to move toward a safe, stable and just society by mending conditions of social conflict, social disintegration, social exclusion, social fragmentation, exclusion and polarization, and by expanding and strengthening conditions of social integration towards peaceful social relations of coexistence, collaboration and cohesion.
  • 10.9K
  • 08 Nov 2022
Topic Review
Decimation (Signal Processing)
In digital signal processing, decimation is the process of reducing the sampling rate of a signal.  The term downsampling usually refers to one step of the process, but sometimes the terms are used interchangeably.  Complementary to upsampling, which increases sampling rate, decimation is a specific case of sample rate conversion in a multi-rate digital signal processing system. A system component that performs decimation is called a decimator. When decimation is performed on a sequence of samples of a signal or other continuous function, it produces an approximation of the sequence that would have been obtained by sampling the signal at a lower rate (or density, as in the case of a photograph). The decimation factor is usually an integer or a rational fraction greater than one. This factor multiplies the sampling interval or, equivalently, divides the sampling rate. For example, if compact disc audio at 44,100 samples/second is decimated by a factor of 5/4, the resulting sample rate is 35,280.
  • 10.8K
  • 23 Nov 2022
Topic Review
Well-Defined
In mathematics, an expression is called well-defined or unambiguous if its definition assigns it a unique interpretation or value. Otherwise, the expression is said to be not well-defined, ill-defined or ambiguous. A function is well-defined if it gives the same result when the representation of the input is changed without changing the value of the input. For instance, if f takes real numbers as input, and if f(0.5) does not equal f(1/2) then f is not well-defined (and thus not a function). The term well-defined can also be used to indicate that a logical expression is unambiguous or uncontradictory. A function that is not well-defined is not the same as a function that is undefined. For example, if f(x) = 1/x, then the fact that f(0) is undefined does not mean that the f is not well-defined — but that 0 is simply not in the domain of f.
  • 10.4K
  • 01 Dec 2022
Topic Review
Odal (Rune)
Template:Infobox rune The Elder Futhark Odal rune (ᛟ), also known as the Othala rune, represents the o sound. Its reconstructed Proto-Germanic name is *ōþalan "heritage; inheritance, inherited estate". It was in use for epigraphy during the 3rd to the 8th centuries. It is not continued in the Younger Futhark, disappearing from the Scandinavian record around the 6th century, but it survived in the Anglo-Saxon Futhorc, and expressed the Old English œ phoneme during the 7th and 8th centuries. Its name is attested as ēðel in the Anglo-Saxon manuscript tradition. The odal rune with serifs (feet) is associated with Nazism and is banned in Germany under laws restricting Nazi symbolism, and other, similar organizations. The rune is encoded in Unicode at code point U+16DF: ᛟ.
  • 10.3K
  • 17 Oct 2022
Topic Review
Information Seeking Behavior
Information seeking behavior refers to the way people search for and utilize information. The term was coined by Thomas D. Wilson in his 1981 paper, on the grounds that the current 'information needs' was unhelpful as a basis for a research agenda, since 'need' could not be directly observed, while how people behaved in seeking information could be observed and investigated. However, there is increasing work in the information searching field that is relating behaviors to underlying needs. In 2000, Wilson described information behavior as the totality of human behavior in relation to sources and channels of information, including both active and passive information-seeking, and information use. He described information seeking behavior as purposive seeking of information as a consequence of a need to satisfy some goal. Information seeking behavior is the micro-level of behavior employed by the searcher in interacting with information systems of all kinds, be it between the seeker and the system, or the pure method of creating and following up on a search. A variety of theories of information behavior – e.g. Zipf's principle of least effort, Brenda Dervin's sensemaking, Elfreda Chatman's life in the round – seek to understand the processes that surround information seeking. The analysis of the most cited publications on information behavior during the first years of this century shows its theoretical nature. Together with some works that have a constructivist focus, using references to Dewey, Kelly, Bruner and Vygotsky, others mention sociological concepts, such as Bourdieu's habitus. Several adopt a constructionist-discursive focus, whereas some, such as Chatman, who can in general be described as using an ethnographic perspective, stand out for the quantity and diversity of references to social research. The term 'information behaviour' was also coined by Wilson and occasioned some controversy on its introduction, but now seems to have been adopted, not only by researchers in information science but also in other disciplines. The digital world is changing human information behavior and process. Focused almost exclusively on information seeking and using, information receiving, a central modality of the process is generally overlooked. As information seeking continues to migrate to the Internet, and artificial intelligence continues to advance the analysis of user behavior on the Internet across a range of user interactions, information receiving moves to the heart of the process, as systems "learn" what users like, want and need, as well as their search habits.
  • 9.6K
  • 09 Oct 2022
Topic Review
Partition (Number Theory)
In number theory and combinatorics, a partition of a positive integer n, also called an integer partition, is a way of writing n as a sum of positive integers. Two sums that differ only in the order of their summands are considered the same partition. (If order matters, the sum becomes a composition.) For example, 4 can be partitioned in five distinct ways: 4 3 + 1 2 + 2 2 + 1 + 1 1 + 1 + 1 + 1 The order-dependent composition 1 + 3 is the same partition as 3 + 1, and the two distinct compositions 1 + 2 + 1 and 1 + 1 + 2 represent the same partition 2 + 1 + 1. A summand in a partition is also called a part. The number of partitions of n is given by the partition function p(n). So p(4) = 5. The notation λ ⊢ n means that λ is a partition of n. Partitions can be graphically visualized with Young diagrams or Ferrers diagrams. They occur in a number of branches of mathematics and physics, including the study of symmetric polynomials and of the symmetric group and in group representation theory in general.
  • 9.2K
  • 04 Nov 2022
Topic Review
Sierpinski Triangle
The Sierpinski triangle (also with the original orthography Sierpiński), also called the Sierpinski gasket or the Sierpinski Sieve, is a fractal and attractive fixed set with the overall shape of an equilateral triangle, subdivided recursively into smaller equilateral triangles. Originally constructed as a curve, this is one of the basic examples of self-similar sets, i.e., it is a mathematically generated pattern that is reproducible at any magnification or reduction. It is named after the Poland mathematician Wacław Sierpiński, but appeared as a decorative pattern many centuries before the work of Sierpiński.
  • 8.6K
  • 04 Nov 2022
Topic Review
Internet Archive
Coordinates: 37°46′56″N 122°28′18″W / 37.782321°N 122.47161137°W / 37.782321; -122.47161137 The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge".[notes 2][notes 3] It provides free public access to collections of digitized materials, including websites, software applications/games, music, movies/videos, moving images, and millions of books. In addition to its archiving function, the Archive is an activist organization, advocating a free and open Internet. As of April 2021, the Internet Archive holds over 30 million books and texts, 8.9 million movies, videos and TV shows, 649,000 software programs, 13,225,000 audio files, 3.8 million images, and 580 billion web pages in the Wayback Machine. The Internet Archive allows the public to upload and download digital material to its data cluster, but the bulk of its data is collected automatically by its web crawlers, which work to preserve as much of the public web as possible. Its web archive, the Wayback Machine, contains hundreds of billions of web captures.[notes 4] The Archive also oversees one of the world's largest book digitization projects.
  • 8.2K
  • 18 Oct 2022
Topic Review
Great Soviet Encyclopedia
The Great Soviet Encyclopedia (GSE; Russian: Большая советская энциклопедия, БСЭ, Bolshaya sovetskaya entsiklopediya) is one of the largest Russian-language encyclopedias, published by the Soviet state from 1926 to 1990, and again since 2002 by Russia (under the name Bolshaya Rossiyskaya entsiklopediya or Great Russian Encyclopedia). The GSE claimed to be "the first Marxist-Leninist general-purpose encyclopedia".
  • 7.8K
  • 31 Oct 2022
Topic Review
Solar Symbol
A solar symbol is a symbol representing the Sun. Common solar symbols include circles (with or without rays), crosses, and spirals. In religious iconography, personifications of the Sun or solar attributes are often indicated by means of a halo or a radiate crown. When the systematic study of comparative mythology first became popular in the 19th century, scholarly opinion tended to over-interpret historical myths and iconography in terms of "solar symbolism". This was especially the case with Max Müller and his followers beginning in the 1860s in the context of Indo-European studies. Many "solar symbols" claimed in the 19th century, such as the swastika, triskele, Sun cross, etc. have tended to be interpreted more conservatively in scholarship since the later 20th century.
  • 7.7K
  • 25 Oct 2022
Topic Review
Focal Point (Game Theory)
In game theory, a focal point (or Schelling point) is a solution that people tend to choose by default in the absence of communication. The concept was introduced by the American economist Thomas Schelling in his book The Strategy of Conflict (1960). Schelling states that "(p)eople can often concert their intentions or expectations with others if each knows that the other is trying to do the same" in a cooperative situation (at page 57), so their action would converge on a focal point which has some kind of prominence compared with the environment. However, the conspicuousness of the focal point depends on time, place and people themselves. It may not be a definite solution.
  • 7.5K
  • 14 Nov 2022
Topic Review
HandWiki
HandWiki is an internet Wiki-style encyclopedia for professional researchers in various branches of science and computer science. As other Wiki type encyclopedias, HandWiki is designed for collaborative editing of articles. Unlike the traditional Wikipedia that uses the categories concept for all articles located in the main namespace, HandWiki uses dedicated namespaces for each topic. This allows creation of "Books" or "Manual" by grouping articles under the same namespace. According to the Handwiki designers, this can simplify organization of articles according to particular topic. HandWiki has the following topics included in the dedicated namespaces: Mathematics, Computers, Analysis, Physics, Astronomy, Biology, Chemistry, Unsolved. In addition to the categories preserved from Wikipedia, HandWiki has its own categories for original articles posted to HandWiki. One notable feature of HandWiki is that it allows to collaborate in real-time on many types of documents (lectures, books, technical documents, etc.) with multiple authors. The text can be protected from viewing, and can only be available for groups of people working on the same project. HandWiki can be used to convert such articles to LaTeX and to use BibTeX for referencing. These two features are a significant advantage for preparing research articles for publication. The HandWiki is designed using the MediaWiki software with additional extensions for inclusion of references to programming codes and BibTeX citations. Handwiki allows adding advertisements to the end of the articles. The advertising icons can be grouped according to the HandWiki topics.
  • 7.4K
  • 18 Oct 2022
Topic Review
International Trade Theory
International trade theory is a sub-field of economics which analyzes the patterns of international trade, its origins, and its welfare implications. International trade policy has been highly controversial since the 18th century. International trade theory and economics itself have developed as means to evaluate the effects of trade policies.
  • 6.9K
  • 14 Nov 2022
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