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Topic Review
Digital Twin: Origin to Future
Digital Twin (DT) refers to the virtual copy or model of any physical entity (physical twin) both of which are interconnected via exchange of data in real time. Conceptually, a DT mimics the state of its physical twin in real time and vice versa. Application of DT includes real-time monitoring, designing/planning, optimization, maintenance, remote access, etc. Its implementation is expected to grow exponentially in the coming decades. The advent of Industry 4.0 has brought complex industrial systems that are more autonomous, smart, and highly interconnected. These systems generate considerable amounts of data useful for several applications such as improving performance, predictive maintenance, training, etc. A sudden influx in the number of publications related to ‘Digital Twin’ has led to confusion between different terminologies related to the digitalization of industries. Another problem that has arisen due to the growing popularity of DT is a lack of consensus on the description of DT as well as so many different types of DT, which adds to the confusion. This paper intends to consolidate the different types of DT and different definitions of DT throughout the literature for easy identification of DT from the rest of the complimentary terms such as ‘product avatar’, ‘digital thread’, ‘digital model’, and ‘digital shadow’. The paper looks at the concept of DT since its inception to its predicted future to realize the value it can bring to certain sectors. Understanding the characteristics and types of DT while weighing its pros and cons is essential for any researcher, business, or sector before investing in the technology.
  • 6.9K
  • 25 Jun 2021
Topic Review
Social Presence Theory
Social presence theory explores how the "sense of being with another" is influenced by digital interfaces in human-computer interactions. Developed from the foundations of interpersonal communication and symbolic interactionism, social presence theory was first formally introduced by John Short, Ederyn Williams, and Bruce Christie in The Social Psychology of Telecommunications. Research on social presence theory has recently developed to examine the efficacy of telecommunications media, including SNS communications. The theory notes that computer-based communication is lower in social presence than face-to-face communication, but different computer-based communications can affect the levels of social presence between communicators and receivers.
  • 6.8K
  • 02 Dec 2022
Topic Review
Quaternary Numeral System
A quaternary /kwəˈtɜːrnəri/ numeral system is base-4. It uses the digits 0, 1, 2 and 3 to represent any real number. Four is the largest number within the subitizing range and one of two numbers that is both a square and a highly composite number (the other being 36), making quaternary a convenient choice for a base at this scale. Despite being twice as large, its radix economy is equal to that of binary. However, it fares no better in the localization of prime numbers (the smallest better base being the primorial base six, senary). Quaternary shares with all fixed-radix numeral systems many properties, such as the ability to represent any real number with a canonical representation (almost unique) and the characteristics of the representations of rational numbers and irrational numbers. See decimal and binary for a discussion of these properties.
  • 6.6K
  • 16 Nov 2022
Topic Review
Gramian Matrix
In linear algebra, the Gram matrix (or Gramian matrix, Gramian) of a set of vectors [math]\displaystyle{ v_1,\dots, v_n }[/math] in an inner product space is the Hermitian matrix of inner products, whose entries are given by [math]\displaystyle{ G_{ij}=\langle v_i, v_j \rangle }[/math]. An important application is to compute linear independence: a set of vectors are linearly independent if and only if the Gram determinant (the determinant of the Gram matrix) is non-zero. It is named after Jørgen Pedersen Gram.
  • 6.3K
  • 27 Oct 2022
Topic Review
Religious Studies
Religious studies, alternately known as the study of religion, is an academic field devoted to research into religious beliefs, behaviors, and institutions. It describes, compares, interprets, and explains religion, emphasizing systematic, historically based, and cross-cultural perspectives. While theology attempts to understand the nature of transcendent or supernatural forces (such as deities), religious studies tries to study religious behavior and belief from outside any particular religious viewpoint. Religious studies draws upon multiple disciplines and their methodologies including anthropology, sociology, psychology, philosophy, and history of religion. Religious studies originated in the 19th century, when scholarly and historical analysis of the Bible had flourished, and Hindu and Buddhist texts were first being translated into European languages. Early influential scholars included Friedrich Max Müller, in England, and Cornelius P. Tiele, in the Netherlands. Today religious studies is practiced by scholars worldwide. In its early years, it was known as Comparative Religion or the Science of Religion and, in the USA, there are those who today also know the field as the History of religion (associated with methodological traditions traced to the University of Chicago in general, and in particular Mircea Eliade, from the late 1950s through to the late 1980s). The term "religion" originated from the Latin noun "religio", that was nominalized from one of three verbs: "relegere" (to turn to constantly/observe conscientiously); "religare" (to bind oneself [back]); and "reeligere" (to choose again). Because of these three different potential meanings, an etymological analysis alone does not resolve the ambiguity of defining religion, since each verb points to a different understanding of what religion is. During the Medieval Period, the term "religious" was used as a noun to describe someone who had joined a monastic order (a "religious"). The religious studies scholar Walter Capps described the purpose of the discipline as to provide "training and practice... in directing and conducting inquiry regarding the subject of religion". At the same time, Capps stated that its other purpose was to use "prescribed modes and techniques of inquiry to make the subject of religion intelligible." Religious studies scholar Robert A. Segal characterised the discipline as "a subject matter" that is "open to many approaches", and thus it "does not require either a distinctive method or a distinctive explanation to be worthy of disciplinary status." Different scholars operating in the field have different interests and intentions; some for instance seek to defend religion, while others seek to explain it away, and others wish to use religion as an example with which to prove a theory of their own. Some scholars of religious studies are interested in primarily studying the religion to which they belong. Scholars of religion have argued that a study of the subject is useful for individuals because it will provide them with knowledge that is pertinent in inter-personal and professional contexts within an increasingly globalised world. It has also been argued that studying religion is useful in appreciating and understanding sectarian tensions and religious violence.
  • 6.3K
  • 22 Nov 2022
Topic Review
News International Phone Hacking Scandal
The News International phone hacking scandal was a controversy involving the now-defunct News of the World and other British newspapers owned by Rupert Murdoch. Employees of the newspaper were accused of engaging in phone hacking, police bribery, and exercising improper influence in the pursuit of stories. Whilst investigations conducted from 2005 to 2007 appeared to show that the paper's phone hacking activities were limited to celebrities, politicians, and members of the British royal family, in July 2011 it was revealed that the phones of murdered schoolgirl Milly Dowler, relatives of deceased British soldiers, and victims of the 7 July 2005 London bombings had also been hacked. The resulting public outcry against News Corporation and its owner Rupert Murdoch led to several high-profile resignations, including that of Murdoch as News Corporation director, Murdoch's son James as executive chairman, Dow Jones chief executive Les Hinton, News International legal manager Tom Crone, and chief executive Rebekah Brooks. The commissioner of London's Metropolitan Police Service (MPS), Sir Paul Stephenson, also resigned. Advertiser boycotts led to the closure of the News of the World on 10 July 2011, after 168 years of publication. Public pressure forced News Corporation to cancel its proposed takeover of the British satellite broadcaster BSkyB. The prime minister David Cameron announced on 6 July 2011 that a public inquiry, known as the Leveson Inquiry, would look into phone hacking and police bribery by the News of the World, consider the wider culture and ethics of the British newspaper industry and that the Press Complaints Commission would be replaced "entirely". A number of arrests and convictions followed, most notably of the former News of the World managing editor Andy Coulson. Murdoch and his son, James, were summoned to give evidence at the Leveson Inquiry. Over the course of his testimony, Rupert Murdoch admitted that a cover-up had taken place within the News of the World to hide the scope of the phone hacking. On 1 May 2012, a parliamentary select committee report concluded that Murdoch "exhibited wilful blindness to what was going on in his companies and publications" and stated that he was "not a fit person to exercise the stewardship of a major international company". On 3 July 2013, Channel 4 News broadcast a secret tape in which Murdoch dismissively claims that investigators were "totally incompetent" and acted over "next to nothing" and excuses his papers' actions as "part of the culture of Fleet Street".
  • 6.3K
  • 11 Oct 2022
Topic Review
Prince of Wales's Feathers
Template:Infobox Coat of arms The Prince of Wales's feathers is the heraldic badge of the Prince of Wales. It consists of three white ostrich feathers emerging from a gold coronet. A ribbon below the coronet bears the motto Ich dien (German: [ɪç ˈdiːn], "I serve"). As well as being used in royal heraldry, the badge is sometimes used to symbolise Wales, particularly in Welsh rugby union and Welsh regiments of the British Army.
  • 6.2K
  • 27 Nov 2022
Topic Review
Partition Problem
In number theory and computer science, the partition problem, or number partitioning, is the task of deciding whether a given multiset S of positive integers can be partitioned into two subsets S1 and S2 such that the sum of the numbers in S1 equals the sum of the numbers in S2. Although the partition problem is NP-complete, there is a pseudo-polynomial time dynamic programming solution, and there are heuristics that solve the problem in many instances, either optimally or approximately. For this reason, it has been called "the easiest hard problem". There is an optimization version of the partition problem, which is to partition the multiset S into two subsets S1, S2 such that the difference between the sum of elements in S1 and the sum of elements in S2 is minimized. The optimization version is NP-hard, but can be solved efficiently in practice.
  • 6.2K
  • 10 Oct 2022
Topic Review
Correlation and Dependence
In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. In the broadest sense correlation is any statistical association, though it commonly refers to the degree to which a pair of variables are linearly related. Familiar examples of dependent phenomena include the correlation between the height of parents and their offspring, and the correlation between the price of a good and the quantity the consumers are willing to purchase, as it is depicted in the so-called demand curve. Correlations are useful because they can indicate a predictive relationship that can be exploited in practice. For example, an electrical utility may produce less power on a mild day based on the correlation between electricity demand and weather. In this example, there is a causal relationship, because extreme weather causes people to use more electricity for heating or cooling. However, in general, the presence of a correlation is not sufficient to infer the presence of a causal relationship (i.e., correlation does not imply causation). Formally, random variables are dependent if they do not satisfy a mathematical property of probabilistic independence. In informal parlance, correlation is synonymous with dependence. However, when used in a technical sense, correlation refers to any of several specific types of mathematical operations between the tested variables and their respective expected values. Essentially, correlation is the measure of how two or more variables are related to one another. There are several correlation coefficients, often denoted [math]\displaystyle{ \rho }[/math] or [math]\displaystyle{ r }[/math], measuring the degree of correlation. The most common of these is the Pearson correlation coefficient, which is sensitive only to a linear relationship between two variables (which may be present even when one variable is a nonlinear function of the other). Other correlation coefficients – such as Spearman's rank correlation – have been developed to be more robust than Pearson's, that is, more sensitive to nonlinear relationships. Mutual information can also be applied to measure dependence between two variables.
  • 6.1K
  • 14 Oct 2022
Topic Review
Records Continuum Model
The Records Continuum Model (RCM) was created in the 1990s by Monash University academic Frank Upward with input from colleagues Sue McKemmish and Livia Iacovino as a response to evolving discussions about the challenges of managing digital records and archives in the discipline of Archival Science. The RCM was first published in Upward’s 1996 paper "Structuring the Records Continuum – Part One: Postcustodial principles and properties". Upward describes the RCM within the broad context of a continuum where activities and interactions transform documents into records, evidence and memory that are used for multiple purposes over time. Upward places the RCM within a post-custodial, postmodern and structuration conceptual framework. Australian academics and practitioners continue to explore, develop and extend the RCM and records continuum theory, along with international collaborators, via the Records Continuum Research Group (RCRG) at Monash University.
  • 6.0K
  • 09 Nov 2022
Topic Review
Hypothetical Construct
In philosophy, a construct is an object which is ideal, that is, an object of the mind or of thought, meaning that its existence may be said to depend upon a subject's mind. This contrasts with any possibly mind-independent objects, the existence of which purportedly does not depend on the existence of a conscious observing subject. Thus, the distinction between these two terms may be compared to that between phenomenon and noumenon in other philosophical contexts and to many of the typical definitions of the terms realism and idealism also. In the correspondence theory of truth, ideas, such as constructs, are to be judged and checked according to how well they correspond with their referents, often conceived as part of a mind-independent reality.
  • 5.9K
  • 23 Nov 2022
Topic Review
List of Citadel Paints
This table contains a list of the Citadel paint range used for painting Citadel Miniatures, produced by Games Workshop. Citadel Miniatures are metal, resin, and plastic miniature gaming figures, accessories, and scenery for Games Workshop's range of tabletop wargames, such as their signature Warhammer Fantasy Battle, and Warhammer 40,000 games and The Lord of the Rings Strategy Battle Game.
  • 5.9K
  • 25 Nov 2022
Topic Review
Microsoft Visual C
Microsoft Visual C++ (often abbreviated to MSVC) is an integrated development environment (IDE) product from Microsoft for the C, C++, and C++/CLI programming languages. MSVC is proprietary software; it was originally a standalone product but later became a part of Visual Studio and made available in both trialware and freeware forms. It features tools for developing and debugging C++ code, especially code written for the Windows API, DirectX and .NET. Many applications require redistributable Visual C++ runtime library packages to function correctly. These packages are often installed independently of applications, allowing multiple applications to make use of the package while only having to install it once. These Visual C++ redistributable and runtime packages are mostly installed for standard libraries that many applications use.
  • 5.9K
  • 11 Oct 2022
Topic Review
Pentium FDIV Bug
The Pentium FDIV bug is a hardware bug affecting the floating point unit (FPU) of the early Intel Pentium processors. Because of the bug, the processor might return incorrect binary floating point results when dividing a number. The bug was discovered in 1994 by Professor Thomas R. Nicely at Lynchburg College. Intel attributed the error to missing entries in the lookup table used by the floating-point division circuitry. The severity of the FDIV bug is debated. Though rarely encountered by most users (Byte magazine estimated that 1 in 9 billion floating point divides with random parameters would produce inaccurate results), both the flaw and Intel's initial handling of the matter were heavily criticized by the tech community. In December 1994, Intel recalled the defective processors. In January 1995, Intel announced "a pre-tax charge of $475 million against earnings, ostensibly the total cost associated with replacement of the flawed processors."
  • 5.8K
  • 04 Nov 2022
Topic Review
The Sims 2 Stuff Packs
Stuff packs are minor expansion packs for The Sims 2 that add new items, clothing, and furniture to the game without implementing any significant changes to gameplay.
  • 5.7K
  • 17 Nov 2022
Topic Review
Muhammad Ibn Musa Al-Khwarizmi
Muḥammad ibn Mūsā al-Khwārizmī (Persian: محمد بن موسی خوارزمی‎, romanized: Moḥammad ben Musā Khwārazmi; c. 780 – c. 850), or al-Khwarizmi and formerly Latinized as Algorithmi, was a Persian polymath who produced vastly influential works in mathematics, astronomy, and geography. Around 820 CE he was appointed as the astronomer and head of the library of the House of Wisdom in Baghdad.:14 Al-Khwarizmi's popularizing treatise on algebra (The Compendious Book on Calculation by Completion and Balancing, c. 813–833 CE:171) presented the first systematic solution of linear and quadratic equations. One of his principal achievements in algebra was his demonstration of how to solve quadratic equations by completing the square, for which he provided geometric justifications.:14 Because he was the first to treat algebra as an independent discipline and introduced the methods of "reduction" and "balancing" (the transposition of subtracted terms to the other side of an equation, that is, the cancellation of like terms on opposite sides of the equation), he has been described as the father or founder of algebra. The term algebra itself comes from the title of his book (the word al-jabr meaning "completion" or "rejoining"). His name gave rise to the terms algorism and algorithm, as well as Spanish and Portuguese terms algoritmo, and Spanish guarismo and Portuguese algarismo meaning "digit". In the 12th century, Latin translations of his textbook on arithmetic (Algorithmo de Numero Indorum) which codified the various Indian numerals, introduced the decimal positional number system to the Western world. The Compendious Book on Calculation by Completion and Balancing, translated into Latin by Robert of Chester in 1145, was used until the sixteenth century as the principal mathematical text-book of European universities. In addition to his best-known works, he revised Ptolemy's Geography, listing the longitudes and latitudes of various cities and localities.:9 He further produced a set of astronomical tables and wrote about calendaric works, as well as the astrolabe and the sundial. He also made important contributions to trigonometry, producing accurate sine and cosine tables, and the first table of tangents.
  • 5.6K
  • 10 Oct 2022
Topic Review
Product Distribution
A product distribution is a probability distribution constructed as the distribution of the product of random variables having two other known distributions. Given two statistically independent random variables X and Y, the distribution of the random variable Z that is formed as the product is a product distribution.
  • 5.6K
  • 11 Nov 2022
Topic Review
The Sims 3 Stuff Packs
Stuff packs are minor expansion packs for The Sims 3 that add new items, clothing, and furniture to the game without implementing any significant changes to gameplay.
  • 5.5K
  • 11 Nov 2022
Topic Review
Home Economics
Home economics, or family and consumer sciences, is a subject concerning human development, personal and family finances, consumer issues, housing and interior design, nutrition and food preparation, as well as textiles and apparel. Home economics courses are offered around the world and across multiple educational levels. Internationally, it is coordinated by the International Federation for Home Economics. Historically, the purpose of these courses was to professionalize housework, to provide intellectual fulfillment for women, and to emphasize the value of "women's work" in society and to prepare them for the traditional roles of sexes. However, it has since evolved into family and consumer sciences to cover additional subject matter outside of just home life and wellness. Family and consumer sciences are taught as an elective or required course in secondary education, as a continuing education course in institutions, and at the primary level.   Beginning as home economics in the United States, the course was a key part of the education system for teaching one the art of taking care of a household. In the 19th and early 20th century, it was a woman-dominated course, teaching women to be homemakers and efficient household managers. The American Association of Family and Consumer Sciences was created as an answer to more Americans desiring youth to learn vocational skills. Politics played a role in home economics education, and it wasn’t until later in the century that the course shifted from being woman-dominated to now required for both sexes.   Now family and consumer science have been included in the broader subject of Career Technical Education, a program that teaches skilled trades, applied sciences, modern technologies, and career preparation. Despite the subjects over the past century, there has been a major decline in home economics courses offered by educational institutions.  
  • 5.4K
  • 09 Nov 2022
Topic Review
Limit Point
In mathematics, a limit point (or cluster point or accumulation point) of a set [math]\displaystyle{ S }[/math] in a topological space [math]\displaystyle{ X }[/math] is a point [math]\displaystyle{ x }[/math] that can be "approximated" by points of [math]\displaystyle{ S }[/math] in the sense that every neighbourhood of [math]\displaystyle{ x }[/math] with respect to the topology on [math]\displaystyle{ X }[/math] also contains a point of [math]\displaystyle{ S }[/math] other than [math]\displaystyle{ x }[/math] itself. A limit point of a set [math]\displaystyle{ S }[/math] does not itself have to be an element of [math]\displaystyle{ S. }[/math] There is also a closely related concept for sequences. A cluster point or accumulation point of a sequence [math]\displaystyle{ (x_n)_{n \in \mathbb{N}} }[/math] in a topological space [math]\displaystyle{ X }[/math] is a point [math]\displaystyle{ x }[/math] such that, for every neighbourhood [math]\displaystyle{ V }[/math] of [math]\displaystyle{ x, }[/math] there are infinitely many natural numbers [math]\displaystyle{ n }[/math] such that [math]\displaystyle{ x_n \in V. }[/math] This definition of a cluster or accumulation point of a sequence generalizes to nets and filters. In contrast to sets, for a sequence, net, or filter, the term "limit point" is not synonymous with a "cluster/accumulation point"; by definition, the similarly named notion of a limit point of a filter (respectively, a limit point of a sequence, a limit point of a net) refers to a point that the filter converges to (respectively, the sequence converges to, the net converges to). The limit points of a set should not be confused with adherent points for which every neighbourhood of [math]\displaystyle{ x }[/math] contains a point of [math]\displaystyle{ S }[/math]. Unlike for limit points, this point of [math]\displaystyle{ S }[/math] may be [math]\displaystyle{ x }[/math] itself. A limit point can be characterized as an adherent point that is not an isolated point. Limit points of a set should also not be confused with boundary points. For example, [math]\displaystyle{ 0 }[/math] is a boundary point (but not a limit point) of set [math]\displaystyle{ \{ 0 \} }[/math] in [math]\displaystyle{ \R }[/math] with standard topology. However, [math]\displaystyle{ 0.5 }[/math] is a limit point (though not a boundary point) of interval [math]\displaystyle{ [0, 1] }[/math] in [math]\displaystyle{ \R }[/math] with standard topology (for a less trivial example of a limit point, see the first caption). This concept profitably generalizes the notion of a limit and is the underpinning of concepts such as closed set and topological closure. Indeed, a set is closed if and only if it contains all of its limit points, and the topological closure operation can be thought of as an operation that enriches a set by uniting it with its limit points.
  • 5.4K
  • 25 Oct 2022
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