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https://en.wikipedia.org/wiki/LSH%20%28hash%20function%29 | LSH is a cryptographic hash function designed in 2014 by South Korea to provide integrity in general-purpose software environments such as PCs and smart devices. LSH is one of the cryptographic algorithms approved by the Korean Cryptographic Module Validation Program (KCMVP).
And it is the national standard of South Korea (KS X 3262).
Specification
The overall structure of the hash function LSH is shown in the following figure.
The hash function LSH has the wide-pipe Merkle-Damgård structure with one-zeros padding.
The message hashing process of LSH consists of the following three stages.
Initialization:
One-zeros padding of a given bit string message.
Conversion to 32-word array message blocks from the padded bit string message.
Initialization of a chaining variable with the initialization vector.
Compression:
Updating of chaining variables by iteration of a compression function with message blocks.
Finalization:
Generation of an -bit hash value from the final chaining variable.
The specifications of the hash function LSH are as follows.
Initialization
Let be a given bit string message.
The given is padded by one-zeros, i.e., the bit ‘1’ is appended to the end of , and the bit ‘0’s are appended until a bit length of a padded message is , where and is the smallest integer not less than .
Let be the one-zeros-padded -bit string of .
Then is considered as a -byte array , where for all .
The -byte array converts into a -word array as follows.
From the word array , we define the 32-word array message blocks as follows.
The 16-word array chaining variable is initialized to the initialization vector .
The initialization vector is as follows.
In the following tables, all values are expressed in hexadecimal form.
Compression
In this stage, the 32-word array message blocks , which are generated from a message in the initialization stage, are compressed by iteration of compression functions.
The compression function has two input |
https://en.wikipedia.org/wiki/Code%20page%201127 | Code page 1127 (CCSID 1127), also known as Arabic / French PC Data, is used by IBM in its PC DOS operating system.
Codepage layout
� Not in Unicode
References
1127 |
https://en.wikipedia.org/wiki/Combinatorial%20Geometry%20in%20the%20Plane | Combinatorial Geometry in the Plane is a book in discrete geometry. It was translated from a German-language book, Kombinatorische Geometrie in der Ebene, which its authors Hugo Hadwiger and Hans Debrunner published through the University of Geneva in 1960, expanding a 1955 survey paper that Hadwiger had published in L'Enseignement mathématique. Victor Klee translated it into English, and added a chapter of new material. It was published in 1964 by Holt, Rinehart and Winston, and republished in 1966 by Dover Publications. A Russian-language edition, , translated by I. M. Jaglom and including a summary of the new material by Klee, was published by Nauka in 1965. The Basic Library List Committee of the Mathematical Association of America has recommended its inclusion in undergraduate mathematics libraries.
Topics
The first half of the book provides the statements of nearly 100 propositions in the discrete geometry of the Euclidean plane, and the second half sketches their proofs. Klee's added chapter, lying between the two halves, provides another 10 propositions, including some generalizations to higher dimensions, and the book concludes with a detailed bibliography of its topics.
Results in discrete geometry covered by this book include:
Carathéodory's theorem that every point in the convex hull of a planar set belongs to a triangle determined by three points of the set, and Steinitz's theorem that every point interior to the convex hull is interior to the convex hull of four points of the set.
The Erdős–Anning theorem, that if an infinite set of points in the plane has an integer distance between every two points, then the given points must all lie on a single line.
Helly's theorem, that if a family of compact convex sets has a non-empty intersection for every triple of sets, then the whole family has a non-empty intersection.
A Helly-like property of visibility related to the art gallery theorem: if every three points of a polygon are visible from some common po |
https://en.wikipedia.org/wiki/Vertex%20cover%20in%20hypergraphs | In graph theory, a vertex cover in a hypergraph is a set of vertices, such that every hyperedge of the hypergraph contains at least one vertex of that set. It is an extension of the notion of vertex cover in a graph.
An equivalent term is a hitting set: given a collection of sets, a set which intersects all sets in the collection in at least one element is called a hitting set. The equivalence can be seen by mapping the sets in the collection onto hyperedges.
Another equivalent term, used more in a combinatorial context, is transversal.
The notions of hitting set and set cover are equivalent too.
Definition
Recall that a hypergraph is a pair , where is a set of vertices and is a set of subsets of called hyperedges. Each hyperedge may contain one or more vertices.
A vertex-cover (aka hitting set or transversal) in is set such that, for all hyperedges , it holds that .
The vertex-cover number (aka transversal number) of a hypergraph is the smallest size of a vertex cover in . It is often denoted by .
For example, if is this 3-uniform hypergraph:
then has admits several vertex-covers of size 2, for example:
However, no subset of size 1 hits all the hyperedges of . Hence the vertex-cover number of is 2.
Note that we get back the case of vertex covers for simple graphs if the maximum size of the hyperedges is 2.
Algorithms
The computational problems minimum hitting set and hitting set are defined as in the case of graphs.
If the maximum size of a hyperedge is restricted to , then the problem of finding a minimum -hitting set permits a -approximation algorithm. Assuming the unique games conjecture, this is the best constant-factor algorithm that is possible and otherwise there is the possibility of improving the approximation to .
For the hitting set problem, different parametrizations make sense. The hitting set problem is -complete for the parameter , that is, it is unlikely that there is an algorithm that runs in time where is the cardina |
https://en.wikipedia.org/wiki/Plasmonics%20%28journal%29 | Plasmonics is a bimonthly peer-reviewed scientific journal covering plasmonics, including the theory of plasmonic metamaterials, fluorescence and surface-enhanced Raman spectroscopy. It is published by Springer Science+Business Media. Its current editor is Chris D. Geddes, Director of the Institute of Fluorescence at the University of Maryland Biotechnology Institute. According to the Journal Citation Reports, the journal has a 2021 impact factor of 2.726.
Abstracting and indexing
The journal is abstracted and indexed in:
Science Citation Index Expanded
Current Contents/Physical, Chemical & Earth Sciences
EBSCO Academic Search
EBSCO Discovery Service
EBSCO Engineering Source
EBSCO STM Source
ProQuest Advanced Technologies & Aerospace Database
ProQuest Central
ProQuest SciTech Premium Collection
ProQuest Technology Collection
ProQuest-ExLibris Primo
ProQuest-ExLibris Summon
References
External links
Springer Science+Business Media academic journals
Optics journals
Nanotechnology journals
Materials science journals
English-language journals
Bimonthly journals
Academic journals established in 2006 |
https://en.wikipedia.org/wiki/Bitvise | Bitvise is a proprietary secure remote access software developed for Windows and available as a client and server. The software is based on the Secure Shell (SSH) protocol, which provides a secure channel over an insecure network in a client-server architecture.
Technology
Bitvise software implements version 2 of the Secure Shell (SSH) protocol, SFTP versions 3, 4, and 6, as well as SCP and FTPS according to publicly available standards.
Development
The software is developed and published by Bitvise Limited. The first released product was Bitvise SSH Server, then named WinSSHD, in 2001, and it was shortly followed by Tunnelier, now Bitvise SSH Client. There have been 8 major releases of the software so far.
Features
Both the server and client work with all desktop and server versions of Windows and allow for remote-based access using a tool like WinVNC. They provide a GUI as well as command-line interface to support SFTP, SSH, SCP, and VPN using the TCP/IP tunneling feature.
The software among other supports GSSAPI-enabled Kerberos 5 exchange and NTLM Kerberos 5 user authentication. It provides two-factor authentication and compatibility with RFC 6238 authenticator apps.
See also
Comparison of SSH clients
Comparison of SSH servers
References
External links
Official website
Computer_security_software
Windows software |
https://en.wikipedia.org/wiki/Vecchia%20approximation | Vecchia approximation is a Gaussian processes approximation technique originally developed by Aldo Vecchia, a statistician at United States Geological Survey. It is one of the earliest attempts to use Gaussian processes in high-dimensional settings. It has since been extensively generalized giving rise to many contemporary approximations.
Intuition
A joint probability distribution for events , and , denoted , can be expressed as
Vecchia's approximation takes the form, for example,
and is accurate when events and are close to conditionally independent given knowledge of . Of course one could have alternatively chosen the approximation
and so use of the approximation requires some knowledge of which events are close to conditionally independent given others. Moreover, we could have chosen
a different ordering, for example
Fortunately, in many cases there are good heuristics making decisions about how to construct the approximation.
More technically, general versions of the approximation lead to a sparse Cholesky factor of the precision matrix. Using the standard Cholesky factorization produces entries which can be interpreted as conditional correlations with zeros indicating no independence (since the model is Gaussian). These independence relations can be alternatively expressed using graphical models and there exist theorems linking graph structure and vertex ordering with zeros in the Cholesky factor. In particular, it is known that independencies that are encoded in a moral graph lead to Cholesky factors of the precision matrix that have no fill-in.
Formal description
The problem
Let be a Gaussian process indexed by with mean function and covariance function . Assume that is a finite subset of and is a vector of values of evaluated at , i.e. for . Assume further, that one observes where with .
In this context the two most common inference tasks include evaluating the likelihood
or making predictions of values of for and , i.e. calculat |
https://en.wikipedia.org/wiki/Gaussian%20process%20approximations | In statistics and machine learning, Gaussian process approximation is a computational method that accelerates inference tasks in the context of a Gaussian process model, most commonly likelihood evaluation and prediction. Like approximations of other models, they can often be expressed as additional assumptions imposed on the model, which do not correspond to any actual feature, but which retain its key properties while simplifying calculations. Many of these approximation methods can be expressed in purely linear algebraic or functional analytic terms as matrix or function approximations. Others are purely algorithmic and cannot easily be rephrased as a modification of a statistical model.
Basic ideas
In statistical modeling, it is often convenient to assume that , the phenomenon under investigation is a Gaussian process indexed by which has mean function and covariance function .
One can also assume that data are values of a particular realization of this process for indices .
Consequently, the joint distribution of the data can be expressed as
,
where and , i.e. respectively a matrix with the covariance function values and a vector with the mean function values at corresponding (pairs of) indices.
The negative log-likelihood of the data then takes the form
Similarly, the best predictor of , the values of for indices , given data has the form
In the context of Gaussian models, especially in geostatistics, prediction using the best predictor, i.e. mean conditional on the data, is also known as kriging.
The most computationally expensive component of the best predictor formula is inverting the covariance matrix , which has cubic complexity . Similarly, evaluating likelihood involves both calculating and the determinant which has the same cubic complexity.
Gaussian process approximations can often be expressed in terms of assumptions on under which and can be calculated with much lower complexity. Since these assumptions are generally not belie |
https://en.wikipedia.org/wiki/Privacy%20settings | Privacy settings are "the part of a social networking website, internet browser, piece of software, etc. that allows you to control who sees information about you". With the growing prevalence of social networking services, opportunities for privacy exposures also grow. Privacy settings allow a person to control what information is shared on these platforms.
Many social networking services (SNS) such as Facebook, have default privacy settings that leave users more prone to sharing personal information. Privacy settings are contributed to by users, companies, and external forces. Contributing factors that influence user activity in privacy settings include the privacy paradox and the third person effect. The third person effect explains why privacy settings can remain unchanged throughout time. Companies can enforce a Principle of Reciprocity (PoR) where users have to decide what information they are willing to share in exchange for others’ information.
With the growing focus on internet privacy, there are technologies and programs designed to enhance and encourage more privacy setting activity. Applications such as the Personal Data Manager (PDM) are used to improve the efficiency of privacy setting management. Privacy by design can enhance privacy settings through incorporating privacy notifications or prompting users to occasionally manage their privacy settings.
Significance
SNS are designed to connect people together online. Users share information and build relationships online. Privacy leaks can still occur even with privacy settings intact. Users’ connections on SNS can reveal personal information such as having friends from the same university can lead to an inference that a person attends that university. Furthermore, even if a person has strict privacy settings enabled, their privacy can still be leaked through their connections who may not have as many privacy settings in place. This calls for enhanced privacy settings that can tolerate different pri |
https://en.wikipedia.org/wiki/Gauge%20theory%20%28mathematics%29 | In mathematics, and especially differential geometry and mathematical physics, gauge theory is the general study of connections on vector bundles, principal bundles, and fibre bundles. Gauge theory in mathematics should not be confused with the closely related concept of a gauge theory in physics, which is a field theory which admits gauge symmetry. In mathematics theory means a mathematical theory, encapsulating the general study of a collection of concepts or phenomena, whereas in the physical sense a gauge theory is a mathematical model of some natural phenomenon.
Gauge theory in mathematics is typically concerned with the study of gauge-theoretic equations. These are differential equations involving connections on vector bundles or principal bundles, or involving sections of vector bundles, and so there are strong links between gauge theory and geometric analysis. These equations are often physically meaningful, corresponding to important concepts in quantum field theory or string theory, but also have important mathematical significance. For example, the Yang–Mills equations are a system of partial differential equations for a connection on a principal bundle, and in physics solutions to these equations correspond to vacuum solutions to the equations of motion for a classical field theory, particles known as instantons.
Gauge theory has found uses in constructing new invariants of smooth manifolds, the construction of exotic geometric structures such as hyperkähler manifolds, as well as giving alternative descriptions of important structures in algebraic geometry such as moduli spaces of vector bundles and coherent sheaves.
History
Gauge theory has its origins as far back as the formulation of Maxwell's equations describing classical electromagnetism, which may be phrased as a gauge theory with structure group the circle group. Work of Paul Dirac on magnetic monopoles and relativistic quantum mechanics encouraged the idea that bundles and connections were t |
https://en.wikipedia.org/wiki/List%20of%20forests%20in%20Iceland | This is a list of forests in Iceland.
There are currently 26 forests under the management of the Icelandic Forest Service. Those forests are classified as national forests in accordance with the Forests and Forestry Act No. 33/2019. National forests may be privately owned but must be managed by the IFS or entities contracted by the IFS, such as individuals, municipalities or legal persons. Contracts between the IFS and private entities granting national forest classification must have a duration of at least 40 years.
List
Akurgerði
Arnaldsstaðaskógur (national forest)
Álfholtsskógur
Ásabrekka
Ásbyrgi (national forest)
Brynjudalsskógur
Bæjarstaðaskógur
Daníelslundur
Einkunnir
Elliðaárdalur
Eyjólfsstaðaskógur
Fossá
Furulundurinn (national forest)
Gaddstaðaflatir
Grundarreitur (national forest)
Guðmundarlundur
Gunnfríðarstaðaskógur
Hallormsstaðaskógur (national forest)
Hamrahlíð
Haukadalsskógur (national forest)
Haukadalur
Hálsaskógur
Hánefsstaðir
Heiðmörk
Hellisskógur
Hofsstaðaskógur
Hrútey
Höfðaskógur
Jafnaskarðsskógur (national forest)
Jórvíkurskógur (national forest)
Kirkjubæjarklaustur
Kirkjuhvammur
Kjarnaskógur
Kristnesskógur (national forest)
Laugalandsskógur
Laugarvatnsskógur (national forest)
Lágafell
Leyningshólar
Mela- og Skuggabjargaskógur (national forest)
Mógilsá (national forest)
Múlakot (national forest)
Norðurtunguskógur (national forest)
Rauðavatn
Reykholtsskógur
Reykjarhólsskógur (national forest)
Selskógur (national forest)
Sigríðarstaðaskógur (national forest)
Skarðsdalur
Skógarhlíð
Skógarreitur (national forest)
Snæfoksstaðir
Sólbrekkuskógur
Stálpastaðaskógur (national forest)
Svartiskógur
Tröð
Tumastaðir (national forest)
Tunguskógur
Vaðlaskógur
Vaglaskógur (national forest)
Vaglir (national forest)
Vatnshornsskógur (national forest)
Vinaskógur
Vífilsstaðavatn
Völvuskógur
Þjórsárdalur (national forest)
Þórðarstaðaskógur (national forest)
Þórsmörk (national forest)
Öskjuhlíð
See also
Icelandic Forest Service
References
External links
Icelandi |
https://en.wikipedia.org/wiki/Polyominoes%3A%20Puzzles%2C%20Patterns%2C%20Problems%2C%20and%20Packings | Polyominoes: Puzzles, Patterns, Problems, and Packings is a mathematics book on polyominoes, the shapes formed by connecting some number of unit squares edge-to-edge. It was written by Solomon Golomb, and is "universally regarded as a classic in recreational mathematics".
The Basic Library List Committee of the Mathematical Association of America has strongly recommended its inclusion in undergraduate mathematics libraries.
Publication history
The book collects together material previously published by Golomb in various articles and columns, especially in Recreational Mathematics Magazine. It was originally published by Scribner's in 1965, titled simply Polyominoes, and including a plastic set of the twelve pentominoes. The book's title word "polyominoes" was invented for the subject by Golomb in 1954 as a back-formation from "domino".
A translation into Russian by I. Yaglom, Полимино, was published by Mir in 1975; it includes also translations of two papers on polyominoes by Golomb and by David A. Klarner.
A second English-language edition of the book was published by the Princeton University Press in 1994. It added to the corrected text of the original addition two more chapters on recent developments, an expanded bibliography, and two appendices, one giving an enumeration of polyominoes and a second reprinting a report by Andy Liu of the solution to all open problems proposed in an appendix to the first edition.
Topics
After an introductory chapter that enumerates the polyominoes up to the hexominoes (made from six squares), the next two chapters of the book concern the pentominoes (made from five squares), the rectangular shapes that can be formed from them, and the subsets of an chessboard into which the twelve pentominoes can be packed.
The fourth chapter discusses brute-force search methods for searching for polyomino tilings or proving their nonexistence, and the fifth introduces techniques from enumerative combinatorics including Burnside's lemma for |
https://en.wikipedia.org/wiki/Subtraction%20game | In combinatorial game theory, a subtraction game is an abstract strategy game whose state can be represented by a natural number or vector of numbers (for instance, the numbers of game tokens in piles of tokens, or the positions of pieces on board) and in which the allowed moves reduce these numbers. Often, the moves of the game allow any number to be reduced by subtracting a value from a specified subtraction set, and different subtraction games vary in their subtraction sets. These games also vary in whether the last player to move wins (the normal play convention) or loses (misère play convention). Another winning convention that has also been used is that a player who moves to a position with all numbers zero wins, but that any other position with no moves possible is a draw.
Examples
Examples of notable subtraction games include the following:
Nim is a game whose state consists of multiple piles of tokens, such as coins or matchsticks, and a valid move removes any number of tokens from a single pile. Nim has a well-known optimal strategy in which the goal at each move is to reach a set of piles whose nim-sum is zero, and this strategy is central to the Sprague–Grundy theorem of optimal play in impartial games. However, when playing only with a single pile of tokens, optimal play is trivial (simply remove all the tokens in a single move).
Subtract a square is a variation of nim in which only square numbers of tokens can be removed in a single move. The resulting game has a non-trivial strategy even for a single pile of tokens; the Furstenberg–Sárközy theorem implies that its winning positions have density zero among the integers.
Fibonacci nim is another variation of nim in which the allowed moves depend on the previous moves to the same pile of tokens. On the first move to a pile, it is forbidden to take the whole pile, and on subsequent moves, the amount subtracted must be at most twice the previous amount removed from the same pile.
Wythoff's game is played |
https://en.wikipedia.org/wiki/Delegated%20credential | Delegated credential is a short-lived TLS certificate used to improve security by faster recovery from private key leakage, without increasing the latency of the TLS handshake. It is currently an IETF Internet Draft, and has been in use by Cloudflare and Facebook, with browser support by Firefox.
Motivation
Modern websites and other services use content delivery networks (CDNs), which are servers potentially distributed all over the world, in order to respond to a user's request as fast as possible, alongside other services that CDNs provide such as DDoS mitigation. However, in order to establish a secure connection, the server is required to prove possession of a private key associated with a certificate, which serves as a chain of trust linking the public key and a trusted party. The trusted party is normally a certificate authority (CA).
CAs issue these digital certificates with an expiration time, usually a few months up to a year. It is the server's responsibility to renew the certificate close to its expiration date. Knowledge of a private key associated to a valid certificate is devastating for the site's security, as it allows Man-in-the-middle attacks, in which a malicious entity can impersonate to a user as a legitimate server. Therefore, these private keys should be kept secure, preferably not distributed over every server in the CDN. Specifically, if a private key is compromised, the corresponding certificate should optimally be revoked, such that browsers will no longer support this certificate. Certificate revocation has two main drawbacks. Firstly, current revocation methods do not work well across all browsers, and put the users at risk; and secondly, upon revocation, the server needs to quickly fetch a new valid certificate from the CA and deploy it across all mirrors.
Design
A delegated credential is a short-lived key (from a few hours to a few days) that the certificate's owner delegates to the server for use in TLS. It is in fact a signature: |
https://en.wikipedia.org/wiki/The%20Fractal%20Dimension%20of%20Architecture | The Fractal Dimension of Architecture is a book that applies the mathematical concept of fractal dimension to the analysis of the architecture of buildings. It was written by Michael J. Ostwald and Josephine Vaughan, both of whom are architecture academics at the University of Newcastle (Australia); it was published in 2016 by Birkhäuser, as the first volume in their Mathematics and the Built Environment book series.
Topics
The book applies the box counting method for computing fractal dimension, via the ArchImage software system, to compute a fractal dimension from architectural drawings (elevations and floor plans) of buildings, drawn at multiple levels of detail. The results of the book suggest that the results are consistent enough to allow for comparisons from one building to another, as long as the general features of the images (such as margins, line thickness, and resolution), parameters of the box counting algorithm, and statistical processing of the results are carefully controlled.
The first five chapters of the book introduce fractals and the fractal dimension, and explain the methodology used by the authors for this analysis, also applying the same analysis to classical fractal structures including the Apollonian gasket, Fibonacci word, Koch snowflake, Minkowski sausage, pinwheel tiling, terdragon, and Sierpiński triangle. The remaining six chapters explain the authors' choice of buildings to analyze, apply their methodology to 625 drawings from 85 homes, built between 1901 and 2007, and perform a statistical analysis of the results.
The authors use this technique to study three main hypotheses, with a fractal structure of subsidiary hypotheses depending on them. These are
That the decrease in the complexity of social family units over the period of study should have led to a corresponding decrease in the complexity of their homes, as measured by a reduction in the fractal dimension.
That distinctive genres and movements in architecture can be charac |
https://en.wikipedia.org/wiki/Arithmologia | Arithmologia, sive De Abditis Numerorum Mysteriis is a 1665 work by the Jesuit scholar Athanasius Kircher. It was published by Varese, the main printing house for the Jesuit order in Rome in the mid-17th century. It was dedicated to Franz III. Nádasdy, a convert to Catholicism to whom Kircher had previously co-dedicated Oedipus Aegyptiacus. Arithmologia is the only one of Kircher's works devoted entirely to different aspects of number symbolism.
Content
Arithmologia was concerned with exploring numbers as the underlying principle and structure of the universe, and as the key to mystic understanding previously revealed to patriarchs and philosophers in ancient times. The field of arithmology may be understood as the intersection of traditional religious numerology and contemporary mathematics, drawing on ideas from Pythagoras, Gnosticism, and the Kabbala. The work discussed the significance of numbers in astrology, divination, magic formulas, amulets, seals and symbolic matrices. Kircher's purpose, as he declared in the final chapter, was to articulate a Christian philosophy of number, revealing the hidden harmonies within the material world and its connections with the spiritual.
Illustrations
The frontispiece depicts, at the top, the all-seeing Eye of Providence within a triangle representing the Holy Trinity. In each angle Hebrew letters spell out Jah, the name of God. Around this the nine orders of angels are arranged in three more overlapping triangles. Beneath this fly two putti, one carrying a ruler and a plumb line, while the other carries a tablet with the magic square of three. Within this square, numbers can be added by row, by column or diagonally, but always add up to fifteen.
In the centre of the image is a winged representation of the cosmos; the winged sphere was an ancient Egyptian symbol that Kircher interpreted as meaning the anima mundi. On the outer rim of this sphere are the primum mobile and the fixed stars, and within them the planets orbit |
https://en.wikipedia.org/wiki/Sarala%20Sagar%20Project | Sarala Sagar is located in Wanaparthy District, Telangana, India, away from National Highway 44.
History
Sarala Sagar Project is the second biggest dam in Asia with siphon technology. It is the oldest project in India after independence Raja of Wanaparthy Raja Rameshwara Rao founded by the Sarala Sagar Dam Project that has incorporated siphon technology from California, United States. 1949 project was inaugurated by the military former Governor of Hyderabad General J.N Chowdary. The project construction stopped 9 years due to some unknown reasons and was later resumed in 1959. Presently this project provides irrigating a vast area of 4,182 Acres of agricultural land in the Wanaparthy district.
The project
Sarala sagar Dam capacity is 0.5 tmcft. Construction of the dam was started on September 15, 1949. Most of the catchment area upstream of this dam is located in Mahabubnagar. Telangana Government has taken priority to construct Mission Kakatiya Phase-III work Rs 2.30 crore for desilting and repair of guide walls of the sarala sagar.
Gallery
References
Dams in Telangana
Irrigation projects
Irrigation in India
Wanaparthy district |
https://en.wikipedia.org/wiki/Black%20box%20model%20of%20power%20converter | The black box model of power converter also called behavior model, is a method of system identification to represent the characteristics of power converter, that is regarded as a black box. There are two types of black box model of power converter - when the model includes the load, it is called terminated model, otherwise un-terminated model. The type of black box model of power converter is chosen based on the goal of modeling. This black box model of power converter could be a tool for filter design of a system integrated with power converters.
To successfully implement a black box model of a power converter, the equivalent circuit of the converter is assumed a-priori, with the assumption that this equivalent circuit remains constant under different operating conditions. The equivalent circuit of the black box model is built by measuring the stimulus/response of the power converter.
Different modeling methods of power converter could be applied in different circumstances. The white box model of power converters is suitable when all the inner components are known, which can be quite difficult due to the complex nature of the power converter. The grey box model combines some features from both, black box model and white box model, when parts of components are known or the relationship between physical elements and equivalent circuit is investigated.
Assumption
Since the power converter consists of power semiconductor device switches, it is a nonlinear and time-variant system. One assumption of black box model of a power converter is that the system is regarded as linear system when the filter is designed properly to avoid saturation and nonlinear effects. Another strong assumption related to the modeling procedure is that the equivalent circuit model is invariant under different operating conditions. Since in the modeling procedures circuit components are determined under different operating conditions.
Equivalent circuit
The expression of a black box model o |
https://en.wikipedia.org/wiki/Rashba%E2%80%93Edelstein%20effect | The Rashba–Edelstein effect (REE) is a spintronics-related effect, consisting in the conversion of a bidimensional charge current into a spin accumulation. This effect is an intrinsic charge-to-spin conversion mechanism and it was predicted in 1990 by the scientist V.M. Edelstein. It has been demonstrated in 2013 and confirmed by several experimental evidences in the following years.
Its origin can be ascribed to the presence of spin-polarized surface or interface states. Indeed, a structural inversion symmetry breaking (i.e., a structural inversion asymmetry (SIA)) causes the Rashba effect to occur: this effect breaks the spin degeneracy of the energy bands and it causes the spin polarization being locked to the momentum in each branch of the dispersion relation. If a charge current flows in these spin-polarized surface states, it generates a spin accumulation. In the case of a bidimensional Rashba gas, where this band splitting occurs, this effect is called Rashba–Edelstein effect.
For what concerns a class of peculiar materials, called topological insulators (TI), spin-splitted surface states exist due to the surface topology, independently from the Rashba effect. Topological insulators, indeed, display a spin-splitted linear dispersion relation on their surfaces (i.e., spin-polarized Dirac cones), while having a band gap in the bulk (this is why these materials are called insulators). Also in this case, spin and momentum are locked and, when a charge current flows in these spin-polarized surface states, a spin accumulation is produced and this effect is called Edelstein effect. In both cases, a 2D charge-to-spin conversion mechanism occurs.
The reverse process is called inverse Rashba–Edelstein effect and it converts a spin accumulation into a bidimensional charge current, resulting in a 2D spin-to-charge conversion.
The Rashba–Edelstein effect and its inverse effect are classified as a spin-charge interconversion (SCI) mechanisms, as the direct and inverse |
https://en.wikipedia.org/wiki/Photovoltaic%20module%20analysis%20techniques | Multiple different photovoltaic module analysis techniques are available and necessary for the inspection of photovoltaic (PV) modules, the detection of occurring degradation and the analysis of cell properties.
The analysis of PV modules during production and operation is an important part in ensuring reliability and thus energy efficiency of the PV technology. Therefore, it is crucial for solar module quality assurance.
During their lifetime, PV modules experience severe changes in weather and working conditions, leading
to large temperature variations (day - night, summer - winter, irradiance) and mechanical stress (wind, snow, hail). This can lead to an enhanced degradation compared to the usual wearing-out of materials over time, resulting in degradation modes (DMs), which can have an (negative) effect on lifetime and power production. To predict the impact of DMs on a PV module or even a PV system, DM detection and evolution studies are needed. Several different analyses techniques are available, as each visualizes and analyzes different DMs and properties, therefore allows specific statements.
Analysis techniques
Some DMs, like snailtracks or glass breakage, are visible by the naked eye. Others, like cell cracks and current mismatches in cells, can be visualized with luminescence techniques, while hot spots can be detected with infrared thermography.
This article gives an overview about common analysis techniques used for operation and maintenance (O&M) of PV modules in the field.
Visual inspection
As it is the cheapest and fastest method, visual inspection is always first choice. It can be done during every inspection of the PV plant, but also more detailed, following a certain procedure. As visual inspection is subjective, evaluation forms are developed to ensure comparability.
Possible defects, which can be identified by visual inspection, are glass breakage, electro-chemical corrosion, burn marks (in front or back sheet), delamination of front g |
https://en.wikipedia.org/wiki/Elastix%20%28image%20registration%29 | Elastix is an image registration toolbox built upon the Insight Segmentation and Registration Toolkit (ITK). It is entirely open-source and provides a wide range of algorithms employed in image registration problems. Its components are designed to be modular to ease a fast and reliable creation of various registration pipelines tailored for case-specific applications. It was first developed by Stefan Klein and Marius Staring under the supervision of Josien P.W. Pluim at Image Sciences Institute (ISI). Its first version was command-line based, allowing the final user to employ scripts to automatically process big data-sets and deploy multiple registration pipelines with few lines of code. Nowadays, to further widen its audience, a version called SimpleElastix is also available, developed by Kasper Marstal, which allows the integration of elastix with high level languages, such as Python, Java, and R.
Image registration fundamentals
Image registration is a well-known technique in digital image processing that searches for the geometric transformation that, applied to a moving image, obtains a one-to-one map with a target image. Generally, the images acquired from different sensors (multimodal), time instants (multitemporal), and points of view (multiview) should be correctly aligned to proceed with further processing and feature extraction. Even though there are a plethora of different approaches to image registration, the majority is composed of the same macro building blocks, namely the transformation, the interpolator, the metric, and the optimizer. Registering two or more images can be framed as an optimization problem that requires multiple iterations to converge to the best solution. Starting from an initial transformation computed from the image moments the optimization process searches for the best transformation parameters based on the value of the selected similarity metric. The figure on the right shows the high-level representation of the registration o |
https://en.wikipedia.org/wiki/Distributed%20Denial%20of%20Secrets | Distributed Denial of Secrets, abbreviated DDoSecrets, is a non-profit whistleblower site for news leaks founded in 2018. Sometimes referred to as a successor to WikiLeaks, it came to international attention for its June 2020 publication of a large collection of internal police documents, known as BlueLeaks. The group has also published data on Russian oligarchs, fascist groups, shell companies, tax havens and banking in the Cayman Islands, as well as data scraped from Parler in January 2021 and from the February 2021 Gab leak. The group is also known for publishing emails from military officials, City Hall in Chicago and the Washington D.C. Metropolitan Police Department. , the site hosts dozens of terabytes of data from over 200 organizations.
The site is a frequent source for other news outlets. The site's leaks have resulted in or contributed to multiple government investigations, including the second impeachment of President Donald J. Trump. During the Russo-Ukrainian War, they were considered one of the best public repositories of all the Russian files leaked since the invasion began.
History
Distributed Denial of Secrets was founded by Emma Best, an American national security reporter known for filing prolific freedom of information requests, and another member of the group known as The Architect. According to Best, The Architect, who they already knew, approached them and expressed their desire to see a new platform for leaked and hacked materials, along with other relevant datasets. The Architect provided the initial technical expertise for the project. At its public launch in December 2018, the site held more than 1 terabyte of data from many of the highest-profile leaks. The site originally considered making all of the data public, but after feedback made some of it available only to journalists and researchers.
Best has served as a public face of the group, which lists its members. In February 2019, they told Columbia Journalism Review there were few |
https://en.wikipedia.org/wiki/MacOS%20Big%20Sur | macOS Big Sur (version 11) is the seventeenth major release of macOS, Apple Inc.'s operating system for Macintosh computers. It was announced at Apple's Worldwide Developers Conference (WWDC) on June 22, 2020, and was released to the public on November 12, 2020.
Big Sur is the successor to macOS Catalina, and was succeeded by macOS Monterey, which was released on October 25, 2021.
Most notably, macOS Big Sur features a user interface redesign that features new blurs to establish a visual hierarchy and also includes a revamp of the Time Machine backup mechanism, among other changes. It is also the first macOS version to support Macs with ARM-based processors. To mark the transition, the operating system's major version number was incremented, for the first time since 2001, from 10 to 11. The operating system is named after the coastal region of Big Sur in the Central Coast of California, continuing the naming trend of California locations that began with OS X Mavericks.
macOS Big Sur is the final version of macOS that supports Macs with Nvidia graphics cards, specifically the 15-inch dual graphics late 2013 and mid 2014 MacBook Pro models, as its successor, macOS Monterey, drops support for those models.
Development history
Providing some indication as to how the pre-release operating system may have been viewed internally at Apple during its development cycle, documentation accompanying the initial beta release of macOS Big Sur referred to its version as "10.16", and when upgrading from prior versions of macOS using the Software Update mechanism to early beta releases, the version referred to was "10.16". An exception to this was the Developer Transition Kit, which always reported the system version as "11.0". macOS Big Sur started reporting the system version as "11.0" on all Macs as of the third beta release.
To maintain backwards compatibility, macOS Big Sur identified itself as 10.16 to software and in the browser user agent.
System requirements
Unlike mac |
https://en.wikipedia.org/wiki/ISocket | iSocket is a smart device brand created by iSocket Systems in 2010. iSocket sends a text message to the user in case of a power outage or other events in a remote location, such as temperature changes, water or gas leaks, or break-ins.
iSocket (which stands for "intelligent socket") was created in the year 2010 by Denis Sokol, the CEO of iSocket Systems. It is a company from Varkaus, Finland. Sokol claims that iSocket was the first smart plug for power outage alerts in the world.
Considered a part of the Internet of things, iSocket was one of the two winners of the Thread Group Innovation Enabler Program for connected homes in the third quarter of 2015.
While most home automation devices depend on the home router's Wi-Fi, iSocket uses a cellular radio and an ordinary SIM card. It also contains a small battery backup so that it can stay powered long enough to alert the user of a power interruption. The socket may include a temperature sensor to monitor temperature during the cold season to avoid frozen pipes. It also sends a message when the power is restored. iSocket makes it possible to turn power on and off with an SMS or a phone call.
Motion, door, smoke, heat, and gas sensors can be connected to iSocket within Ceco Home, the company's home monitoring system.
References
External links
iSocket World
Internet of things
Smart devices |
https://en.wikipedia.org/wiki/Solving%20the%20Riddle%20of%20Phyllotaxis | Solving the Riddle of Phyllotaxis: Why the Fibonacci Numbers and the Golden Ratio Occur in Plants is a book on the mathematics of plant structure, and in particular on phyllotaxis, the arrangement of leaves on plant stems. It was written by Irving Adler, and published in 2012 by World Scientific. The Basic Library List Committee of the Mathematical Association of America has suggested its inclusion in undergraduate mathematics libraries.
Background
Irving Adler (1913–2012) was known as a peace protester, schoolteacher, and children's science book author before, in 1961, earning a doctorate in abstract algebra. Even later in his life, Adler began working on phyllotaxis, the mathematical structure of leaves on plant stems. This book, which collects several of his papers on the subject previously published in journals and edited volumes, is the last of his 85 books to be published before his death.
Topics
Different plants arrange their leaves differently, for instance on alternating sides of the plant stem, or rotated from each other by other fractions of a full rotation between consecutive leaves. In these patterns, rotations by 1/2 of an angle, 1/3 of an angle, 3/8 of an angle, or 5/8 of an angle are common, and it does not appear to be coincidental that the numerators and denominators of these fractions are all Fibonacci numbers. Higher Fibonacci numbers often appear in the number of spiral arms in the spiraling patterns of sunflower seed heads, or the helical patterns of pineapple cells. The theme of Adler's work in this area, in the papers reproduced in this volume, was to find a mathematical model for plant development that would explain these patterns and the occurrence of the Fibonacci numbers and the golden ratio within them.
The papers are arranged chronologically; they include four journal papers from the 1970s, another from the late 1990s, and a preface and book chapter also from the 1990s. Among them, the first is the longest, and reviewer Adhemar Bult |
https://en.wikipedia.org/wiki/Honeywell%20JetWave | Honeywell's JetWave is a piece of satellite communications hardware produced by Honeywell that enables global in-flight internet connectivity. Its connectivity is provided using Inmarsat’s GX Aviation network. The JetWave platform is used in business and general aviation, as well as defense and commercial airline users.
History
In 2012, Honeywell announced it would provide Inmarsat with the hardware for its GX Ka-band in-flight connectivity network. The Ka-band (pronounced either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 27.5 to 31 gigahertz (GHz). In satellite communications, the Ka-band allows higher bandwidth communication.
In 2017, after five years and more than 180 flight hours and testing, JetWave was launched as part of GX Aviation with Lufthansa Group. Honeywell’s JetWave was the exclusive terminal hardware option for the Inmarsat GX Aviation network; however, the exclusivity clause in that contract has expired.
In July 2019, the United States Air Force selected Honeywell’s JetWave satcom system for 70 of its C-17 Globemaster III cargo planes. In December 2019, it was reported that six AirAsia aircraft had been fitted with Inmarsat’s GX Aviation Ka-band connectivity system and is slated to be implemented fleetwide across AirAsia’s Airbus A320 and A330 models in 2020, requiring installation of JetWave atop AirAsia’s fuselages. Today, Honeywell’s JetWave hardware is installed on over 1,000 aircraft worldwide.
In August 2021, the Civil Aviation Administration of China approved a validation of Honeywell’s MCS-8420 JetWave satellite connectivity system for Airbus 320 aircraft.
In December 2021, Honeywell, SES, and Hughes Network Systems demonstrated multi-orbit high-speed airborne connectivity for military customers using Honeywell’s JetWave MCX terminal with a Hughes HM-series modem, and SES satellites in both medium Earth orbit (MEO) and geostationary orbit (GEO). T |
https://en.wikipedia.org/wiki/Ann%20and%20H.J.%20Smead%20Department%20of%20Aerospace%20Engineering%20Sciences | The Ann and H.J. Smead Department of Aerospace Engineering Sciences is a department within the College of Engineering & Applied Science at the University of Colorado Boulder, providing aerospace education and research. Housed primarily in the Aerospace Engineering Sciences building on the university's East Campus in Boulder, it awards baccalaureate, masters, and PhD degrees, as well as certificates, graduating approximately 225 students annually. The Ann and H.J. Smead Department of Aerospace Engineering Sciences is ranked 10th in the nation in both undergraduate and graduate aerospace engineering education among public universities by US News & World Report.
History
Aerospace engineering at the University of Colorado Boulder initially began as an option within the university’s mechanical engineering program in 1930. In 1946, it was split off and became the Department of Aeronautical Engineering under the leadership of aerospace education pioneer Karl Dawson Wood, who served as its first chair. It was renamed the Department of Aerospace Engineering Sciences in 1963.
Both the State of Colorado and the department grew as aerospace research centers during the space race. In 1948. The Laboratory for Atmospheric and Space Physics was founded on campus as the Upper Air Laboratory, followed a few years later by Ball Aerospace Corporation, which opened a research facility in Boulder that eventually became their headquarters, and Lockheed Martin Space Systems, which established a strategic plant in nearby southwest Denver in 1955.
The later addition of numerous federal research labs to the Boulder landscape, including the National Institute of Standards and Technology (NIST), National Oceanic and Atmospheric Administration, National Center for Atmospheric Research, and in Golden, the National Renewable Energy Laboratory, further expanded the area’s research center.
Today, Boulder and the surrounding Denver Metro are home to operations for large aerospace corporations an |
https://en.wikipedia.org/wiki/Stress%20wave%20communication | Stress wave communication is a technique of sending and receiving messages using host structure itself as the transmission medium.
Conventional modulation methods such as amplitude-shift keying (ASK), frequency-shift keying (FSK), phase-shift keying (PSK), quadrature amplitude modulation (QAM), pulse-position modulation (PPM) and orthogonal frequency-division multiplexing (OFDM) could be leveraged for stress wave communication. The challenge to use stress wave as the carrier of the communication is the severe signal distortions due to the multipath channel dispersion. Compared with other communication techniques, it is a very reliable communication for special applications, such as within concrete structures, well drilling string, pipeline structures and so on.
References
Quantized radio modulation modes
Applied probability
Fault tolerance |
https://en.wikipedia.org/wiki/Umbrellar | Umbrellar Ltd. is a New Zealand privately owned Internet web hosting company headquartered in Auckland, New Zealand and incorporated in New Zealand.
Its services are utilised by small businesses, marketing agencies, web specialists, and large corporate enterprises across New Zealand, Australia and Asia.
History
The company, dating back to 1997, was formed from the amalgamation of 10 New Zealand domain name and web hosting brands including Digiweb, Web Drive & Freeparking.
Infrastructure
Umbrellar has a data-centre located in Albany Heights. One of four data-centres operated by Umbrellar.
Acquisitions
13 June 2012, Digiweb (now Umbrellar) announced that it would acquire Digital Network Limited, a fellow provider of hosting services and domain name management. Adrian Grant was Managing Director at the time.
8 September 2014, Web Drive was sold to Digiweb Holdings Limited. Daniel Williams & Steve Hogg were directors of Web Drive at the time.
2005, 2day.com acquired by Freeparking.
Ownership
PenCarrow PE owns 82.8% of Umbrellar via its holding company DWDA Holdings Limited. Smaller shareholders include 10.5% owned by DWDA LTIS Trustee Ltd, 3.9% by Aminoex Trustees & RDP Trusteed Ltd. (owned by current CFO Robert Rolls), 1.63% by Adrian Grant, 1.12% by Robin Dickie.
References
External links
Companies based in Auckland
Domain name registrars
Web hosting
New Zealand companies established in 1997
Computer companies established in 1997 |
https://en.wikipedia.org/wiki/Computational%20microscopy | Computational microscopy is a subfield of computational imaging, which combines algorithmic reconstruction with sensing to capture microscopic images of objects. The algorithms used in computational microscopy often combine the information of several images captured using various illuminations or measurements to form an aggregated 2D or 3D image using iterative techniques or machine learning. Notable forms of computational microscopy include super-resolution fluorescence microscopy, quantitative phase imaging, and Fourier ptychography. Computational microscopy is at the intersection of computer science and optics.
References
Imaging
Microscopy
Multidimensional signal processing |
https://en.wikipedia.org/wiki/Pok%C3%A9mon%20Unite | Pokémon Unite (stylized as Pokémon UNITE) is a free-to-play, multiplayer online battle arena video game developed by TiMi Studio Group and published by The Pokémon Company for Android and iOS and by Nintendo for the Nintendo Switch. It was announced in a Pokémon Presents presentation on 24 June 2020. The game was released for the Nintendo Switch on 21 July 2021, and was released for Android and iOS in 73 countries on 22 September 2021. As of August 2022, the game has been downloaded over 80 million times across all platforms.
Gameplay
Pokémon Unite is a multiplayer online battle arena game, with standard matches consisting of two teams, each with 5 players. Each match is limited to 10 minutes in duration, and the team with the highest total score by the end of each match wins. If there is a tie, the team that reached the final score first (i.e. was previously leading in points) wins. A team can also win if the opposing team surrenders, which can only occur once the match reaches the halfway mark, and only if a supermajority of one team votes to surrender. There are limited time events with special rules, and a game mode called Quick Battle, 5 minute matches on smaller maps with 3-4 players per team and some changes to the rules.
Each player starts a match controlling a relatively weak Pokémon. The Pokémon may become stronger and gain access to new "moves" by capturing wild Pokémon, helping defeat wild Pokémon that their teammate captures, and knocking out enemy player Pokémon. The "type" system common in other Pokémon games, a system similar to rock paper scissors that determines each Pokémon's effectiveness against others, is absent from Pokémon Unite. However, the game includes a new mechanic to the series known as "Unite Moves", which are moves similar to Ultimate moves in other MOBAs, and are unique to each Pokémon and are unlocked at certain levels depending on the Pokémon. , over 20 playable Pokémon were officially revealed or found in the beta testing versi |
https://en.wikipedia.org/wiki/Global%20Goal%3A%20Unite%20for%20Our%20Future | Global Goal: Unite for Our Future was a virtual event held on June 27, 2020. Created by Global Citizen and the European Commission, it consisted of a summit and a concert featuring different personalities aimed to highlight the disproportionate impact of the COVID-19 pandemic on marginalized communities.
The event was produced in collaboration with companies such as Live Nation Entertainment, The Lede Company, and Roc Nation, and also by individuals such as Michele Anthony of the Universal Music Group, Declan Kelly of Teneo, Scooter Braun (with his company SB Projects), Adam Leber (on behalf of Maverick), and Derrick Johnson (on behalf of the NAACP).
Summit
The summit, titled Global Goal: Unite for Our Future—The Summit, featured panel discussions and interviews with world leaders, corporations and philanthropists as they announce new commitments to help develop equitable distribution of COVID-19 tests, treatments and vaccines, as well as rebuild communities devastated by the pandemic. It will be produced by Michael Dempsey and hosted by journalists Katie Couric, Mallika Kapur, Morgan Radford, Isha Sesay, and Keir Simmons.
Participants
Concert
The concert, titled Global Goal: Unite for Our Future—The Concert, was hosted by actor Dwayne Johnson. It was a worldwide music and entertainment special claiming to celebrate the commitments made due to the actions Global Citizens have taken.
Performers
Additional performers
Chloe x Halle
Christine and the Queens
J’Nai Bridges with Gustavo Dudamel, the Los Angeles Philharmonic and Youth Orchestra Los Angeles
For Love Choir
Appearances
Chris Rock
Hugh Jackman
Kerry Washington
Charlize Theron
Forest Whitaker
David Beckham
Salma Hayek
Billy Porter
Diane Kruger
Antoni Porowski
Ken Jeong
Naomi Campbell
Nikolaj Coster-Waldau
Olivia Colman
Broadcast
The event was broadcast in the United States on NBC, MSNBC, Bloomberg Television, iHeartRadio, Sirius XM, and InsightTV.
International broadcasters
Africa |
https://en.wikipedia.org/wiki/Sphere%20packing%20in%20a%20cylinder | Sphere packing in a cylinder is a three-dimensional packing problem with the objective of packing a given number of identical spheres inside a cylinder of specified diameter and length. For cylinders with diameters on the same order of magnitude as the spheres, such packings result in what are called columnar structures.
These problems are studied extensively in the context of biology, nanoscience, materials science, and so forth due to the analogous assembly of small particles (like cells and atoms) into cylindrical crystalline structures.
Appearance in science
Columnar structures appear in various research fields on a broad range of length scales from metres down to the nanoscale. On the largest scale, such structures can be found in botany where seeds of a plant assemble around the stem. On a smaller scale bubbles of equal size crystallise to columnar foam structures when confined in a glass tube. In nanoscience such structures can be found in man-made objects which are on length scales from a micron to the nanoscale.
Botany
Columnar structures were first studied in botany due to their diverse appearances in plants. D'Arcy Thompson analysed such arrangement of plant parts around the stem in his book "On Growth and Form" (1917). But they are also of interest in other biological areas, including bacteria, viruses, microtubules, and the notochord of the zebra fish.
One of the largest flowers where the berries arrange in a regular cylindrical form is the titan arum. This flower can be up to 3m in height and is natively solely found in western Sumatra and western Java.
On smaller length scales, the berries of the Arum maculatum form a columnar structure in autumn. Its berries are similar to that of the corpse flower, since the titan arum is its larger relative. However, the cuckoo-pint is much smaller in height (height ≈ 20 cm). The berry arrangement varies with the stem to berry size.
Another plant that can be found in many gardens of residential areas is the |
https://en.wikipedia.org/wiki/Issues%20relating%20to%20social%20networking%20services | The advent of social networking services has led to many issues spanning from misinformation and disinformation to privacy concerns related to public and private personal data.
Spamming
Spamming on online social networks is quite prevalent. The primary motivation for spamming is to make money, usually from some form of advertising. Detecting such spamming activity has been well studied by developing a semi-automated model to detect spam. For instance, text mining techniques are leveraged to detect regular activity of spamming which reduces the viewership and brings down the reputation (or credibility) of a public pages maintained over Facebook. On some online social networks like Twitter, users have evolved mechanisms to report spammers which has been studied and analyzed.
Privacy
Privacy concerns with social networking services have been raised, with growing concern from users about the privacy of their personal information and the threat of sexual predators. Users of these services also need to be aware of data theft and viruses. However, large services, such as Myspace and Netlog, often work with law enforcement to try to prevent such incidents. In addition, there is a perceived privacy threat in relation to placing too much personal information in the hands of large corporations or governmental bodies, allowing a profile to be produced on an individual's behavior on which decisions, detrimental to an individual, may be taken. Furthermore, there is an issue over the control of data and information that was altered or removed by the user may, in fact, be retained and passed to third parties. This danger was highlighted when the controversial social networking site Quechup harvested e-mail addresses from users' e-mail accounts for use in a spamming operation.
In medical and scientific research, asking subjects for information about their behaviors is normally strictly scrutinized by institutional review boards, for example, to ensure that adolescents and thei |
https://en.wikipedia.org/wiki/Extremal%20Problems%20For%20Finite%20Sets | Extremal Problems For Finite Sets is a mathematics book on the extremal combinatorics of finite sets and families of finite sets. It was written by Péter Frankl and Norihide Tokushige, and published in 2018 by the American Mathematical Society as volume 86 of their Student Mathematical Library book series. The Basic Library List Committee of the Mathematical Association of America has suggested its inclusion in undergraduate mathematics libraries.
Topics
The book has 32 chapters. Its topics include:
Sperner's theorem, on the largest antichain in the family of subsets of a given finite set.
The Sauer–Shelah lemma, on the largest size of a family of sets that avoids shattering any set of given size.
The Erdős–Ko–Rado theorem, on the largest pairwise-intersecting family of subsets of a given finite set, with multiple proofs; the closely related Lubell–Yamamoto–Meshalkin inequality; the Hilton-Milner theorem, on the largest intersecting family with no element in common; and a conjecture of Václav Chvátal that the largest intersecting family of any downward-closed family of sets is always achieved by a family with an element in common.
The Kruskal–Katona theorem relating the size of a family of equal-sized sets and the size of the family of subsets of its sets of a smaller equal size.
Cap sets and the sunflower conjecture on families of sets with equal pairwise intersection.
Open problems including Frankl's union-closed sets conjecture.
Many other results in this area are also included.
Audience and reception
Although the book is intended for undergraduate mathematics students, reviewer Mark Hunacek suggests that readers will either need to be familiar with, or comfortable looking up, terminology for hypergraphs and metric spaces. He suggests that the appropriate audience for the book would be advanced undergraduates who have already demonstrated an interest in combinatorics. However, despite the narrowness of this group, he writes that the book will likely be very val |
https://en.wikipedia.org/wiki/Forward%20problem%20of%20electrocardiology | The forward problem of electrocardiology is a computational and mathematical approach to study the electrical activity of the heart through the body surface. The principal aim of this study is to computationally reproduce an electrocardiogram (ECG), which has important clinical relevance to define cardiac pathologies such as ischemia and infarction, or to test pharmaceutical intervention. Given their important functionalities and the relative small invasiveness, the electrocardiography techniques are used quite often as clinical diagnostic tests. Thus, it is natural to proceed to computationally reproduce an ECG, which means to mathematically model the cardiac behaviour inside the body.
The three main parts of a forward model for the ECG are:
a model for the cardiac electrical activity;
a model for the diffusion of the electrical potential inside the torso, which represents the extracardiac region;
some specific heart-torso coupling conditions.
Thus, to obtain an ECG, a mathematical electrical cardiac model must be considered, coupled with a diffusive model in a passive conductor that describes the electrical propagation inside the torso.
The coupled model is usually a three-dimensional model expressed in terms of partial differential equations. Such model is typically solved by means of finite element method for the solution's space evolution and semi-implicit numerical schemes involving finite differences for the solution's time evolution. However, the computational costs of such techniques, especially with three dimensional simulations, are quite high. Thus, simplified models are often considered, solving for example the heart electrical activity independently from the problem on the torso. To provide realistic results, three dimensional anatomically realistic models of the heart and the torso must be used.
Another possible simplification is a dynamical model made of three ordinary differential equations.
Heart tissue models
The electrical activity of the |
https://en.wikipedia.org/wiki/Applications%20of%20sensitivity%20analysis%20to%20multi-criteria%20decision%20making | A sensitivity analysis may reveal surprising insights in multi-criteria decision making (MCDM) studies aimed to select the best alternative among a number of competing alternatives.
This is an important task in decision making. In such a setting each alternative is described in terms of a set of evaluative criteria. These criteria are associated with weights of importance. Intuitively, one may think that the larger the weight for a criterion is, the more critical that criterion should be. However, this may not be the case. It is important to distinguish here the notion of criticality with that of importance. By critical, we mean that a criterion with small change (as a percentage) in its weight, may cause a significant change of the final solution. It is possible criteria with rather small weights of importance (i.e., ones that are not so important in that respect) to be much more critical in a given situation than ones with larger weights. That is, a sensitivity analysis may shed light into issues not anticipated at the beginning of a study. This, in turn, may dramatically improve the effectiveness of the initial study and assist in the successful implementation of the final solution.
References
Mathematical modeling
Mathematical and quantitative methods (economics) |
https://en.wikipedia.org/wiki/Graph%20Fourier%20transform | In mathematics, the graph Fourier transform is a mathematical transform which eigendecomposes the Laplacian matrix of a graph into eigenvalues and eigenvectors. Analogously to the classical Fourier transform, the eigenvalues represent frequencies and eigenvectors form what is known as a graph Fourier basis.
The Graph Fourier transform is important in spectral graph theory. It is widely applied in the recent study of graph structured learning algorithms, such as the widely employed convolutional networks.
Definition
Given an undirected weighted graph , where is the set of nodes with ( being the number of nodes) and is the set of edges, a graph signal is a function defined on the vertices of the graph . The signal maps every vertex to a real number . Any graph signal can be projected on the eigenvectors of the Laplacian matrix . Let and be the eigenvalue and eigenvector of the Laplacian matrix (the eigenvalues are sorted in an increasing order, i.e., ), the graph Fourier transform (GFT) of a graph signal on the vertices of is the expansion of in terms of the eigenfunctions of . It is defined as:
where .
Since is a real symmetric matrix, its eigenvectors form an orthogonal basis. Hence an inverse graph Fourier transform (IGFT) exists, and it is written as:
Analogously to the classical Fourier transform, graph Fourier transform provides a way to represent a signal in two different domains: the vertex domain and the graph spectral domain. Note that the definition of the graph Fourier transform and its inverse depend on the choice of Laplacian eigenvectors, which are not necessarily unique. The eigenvectors of the normalized Laplacian matrix are also a possible base to define the forward and inverse graph Fourier transform.
Properties
Parseval's identity
The Parseval relation holds for the graph Fourier transform, that is, for any
This gives us Parseval's identity:
Generalized convolution operator
The definition of convolution between |
https://en.wikipedia.org/wiki/Applications%20of%20sensitivity%20analysis%20to%20model%20calibration | Sensitivity analysis has important applications in model calibration.
One application of sensitivity analysis addresses the question of "What's important to model or system development?" One can seek to identify important connections between observations, model inputs, and predictions or forecasts. That is, one can seek to understand what observations (measurements of dependent variables) are most and least important to model inputs (parameters representing system characteristics or excitation), what model inputs are most and least important to predictions or forecasts, and what observations are most and least important to the predictions and forecasts. Often the results are surprising, lead to finding problems in the data or model development, and fixing the problems. This leads to better models.
In biomedical engineering, sensitivity analysis can be used to determine system dynamics in ODE-based kinetic models. Parameters corresponding to stages of differentiation can be varied to determine which parameter is most influential on cell fate. Therefore, the most limiting step can be identified and the cell state for most advantageous scale-up and expansion can be determined. Additionally, complex networks in systems biology can be better understood through fitting mass-action kinetic models. Sensitivity analysis on rate coefficients can then be conducted to determine optimal therapeutic targets within the system of interest.
References
Mathematical modeling
Mathematical analysis |
https://en.wikipedia.org/wiki/Cell%20to%20Singularity | Cell to Singularity is an incremental game developed and published by Computer Lunch. An exploration of evolution, naturalism, and civilization, the game uses idle mechanics to help players learn about science and history. Cell to Singularity is a freemium game; while the game is free and can be played without spending money, players can buy special "boosts" or in-game currency that will help them advance faster.
Gameplay
The game begins with a view of the Earth from space. Players must use their fingers or mouse to tap on the Hadean Earth; tapping generates Entropy Points. After tapping some points, the Tech Tree of Life is then unlocked. Entropy is used to unlock upgrades, and to purchase life forms that automatically generate Entropy. Progression involves increasing the player's Entropy accumulation, advancing further through different eras of Earth’s history as they obtain more Entropy. When the planet and its organisms evolve, visual changes occur in 3D modeled "gardens" where the player can view the creatures and developments that they’ve purchased.
Evolving homo sapiens unlocks a new currency for the player called Idea Points. Players gain currencies continuously, with the simulation continuing to earn points while the game is offline. Occasionally, "boosts" may become available, which allow the player to gain a small advantage in the game. This game's premium currency, purple cubes of a fictional substance called "Darwinium" (named after Charles Darwin) can be obtained via in-app purchase or through in-game events or achievements.
Players will eventually reach the point of creating a technological singularity in the civilization tree. This causes the simulation to “crash” and restart from the beginning. This is, in reality, a prestige mechanic: the player's earned Entropy and Idea Points are converted into a new currency called MetaBits, which are used to upgrade the simulation and unlock new areas of study in the Reality Engine.
Expansions
Mesozoic |
https://en.wikipedia.org/wiki/List%20of%20descriptive%20plant%20species%20epithets%20%28A%E2%80%93H%29 | Since the first printing of Carl Linnaeus's Species Plantarum in 1753, plants have been assigned one epithet or name for their species and one name for their genus, a grouping of related species. These scientific names have been catalogued in a variety of works, including Stearn's Dictionary of Plant Names for Gardeners. William Stearn (1911–2001) was one of the pre-eminent British botanists of the 20th century: a Librarian of the Royal Horticultural Society, a president of the Linnean Society and the original drafter of the International Code of Nomenclature for Cultivated Plants.
The first column below lists seed-bearing species epithets from Stearn's Dictionary, Latin for Gardeners by Lorraine Harrison, The A to Z of Plant Names by Allen Coombes, The Gardener's Botanical by Ross Bayton, and the glossary of Stearn's Botanical Latin. Epithets from proper nouns, proper adjectives, and two or more nouns are excluded, along with epithets used only in species names that are no longer widely accepted. Classical and modern meanings are provided in the third column, along with citations to Charlton T. Lewis's An Elementary Latin Dictionary.
Key
LG = language: (L)atin or (G)reek
L = derived from Latin, or both Classical Latin and Greek (unless otherwise noted)
G = derived from Greek
H = listed by Harrison, and (except as noted) by Bayton
D = listed in Stearn's Dictionary
S = listed in Stearn's Botanical Latin
DS = listed in Stearn's Dictionary, with the word or root word listed in Botanical Latin
C = listed by Coombes
Epithets
See also
Glossary of botanical terms
List of Greek and Latin roots in English
List of Latin and Greek words commonly used in systematic names
List of plant genus names with etymologies: A–C, D–K, L–P, Q–Z
List of plant genera named for people: A–C, D–J, K–P, Q–Z
List of plant family names with etymologies
Notes
Citations
References
Available online at the Perseus Digital Library.
See http://www.plantsoftheworldonline.o |
https://en.wikipedia.org/wiki/List%20of%20herbaria%20in%20Turkey | The following is a list of herbaria in Turkey. Herbaria are established within faculties and institutes of credible universities. Those created in departments that are concerned with natural sciences such as botany, ecology, biogeography and climatology are mostly used to do research on the genetics of the plants, to examine their distribution on specific geographical locations and to protect them for future generations, while those affiliated with more practice-based departments such as pharmacy are used as a resource for drug production techniques.
The first herbarium in Turkey was opened in 1933 within the Faculty of Science at Ankara University. Founded by Kurt Krause and Hikmet Birand, this herbarium is the oldest among its counterparts in the country and has the most number of species within its 200,000-piece collection. Therefore, it is also called Herbarium Turcicum (Turkish Herbarium). The Sugar Institute Herbarium, Atatürk University Faculty of Science Herbarium and Ege University Faculty of Pharmacy Herbarium are closed to visitors and scientific researchers. However, thanks to a specially created website, it is possible to access all the data related to the Ege University Faculty of Pharmacy Herbarium remotely. Altınbaş University Faculty of Pharmacy Herbarium, which opened in 2018, is the first herbarium to be established by a private university. In addition, Anadolu, Ankara, Ege, Marmara, Onsekiz Mart and Siirt universities have two herbaria each, while Hacettepe, Istanbul and Yüzüncü Yıl universities have three herbaria each. As of 2020, there are 55 herbaria in 34 different provinces of Turkey.
Naming and abbreviation
To create a herbarium, it is necessary to do a serious research, using archiving and preservation techniques. Although herbaria are usually established within universities' science and pharmacy faculties, institutions such as botanical gardens or natural history museums can also create their own collections. However, aside from prese |
https://en.wikipedia.org/wiki/Digital%20antenna%20array | Digital antenna array (DAA) is a smart antenna with multi channels digital beamforming, usually by using fast Fourier transform (FFT).
The development and practical realization of digital antenna arrays theory started in 1962 under the guidance of Vladimir Varyukhin (USSR).
History
The history of the DAA was started to emerge as a theory of multichannel analysis in the 1920s. In the 1940s this theory evolved to the theory of three-channel antenna analyzers.
The implementation of effective signal processing in radars by the end of the 1950s predetermined the use of electronic computers in this field. In 1957, Ben S. Meltont and Leslie F. Bailey published article regarding using algebraic operations for signal processing with the help of electronic circuits or analog computer.
Three years after in 1960 the idea of using high-speed computers to solve directional finding problems was embodied, initially to locate earthquake epicenter. B. A. Bolt was one of the first who implemented this idea in practice. Almost simultaneously a similar approach was used by Flinn, a research fellow of the Australian National University.
Despite the fact that in the mentioned experiments the interaction between sensors and computers was implemented with the help of data input cards, such decision was a decisive step on the way of the appearance of the DAA. Then, it was needed only to solve the problem of direct digital data input into the computer from sensors, excluding the step of preparation of punch card and operator assistance as a surplus element. This step for radars theory was made after 1962 in the former USSR conducted with a solution to the problem of superRayleigh resolution of the emission sources.
Digital beamforming
The main approach to digital signal processing in DAA is the "digital beamforming" after Analog-to-digital converters (ADC) of receiver channels or before Digital-to-analog converters (DAC) by transmission.
Digital beamforming of DAA has advantages b |
https://en.wikipedia.org/wiki/MsQuic | MsQuic is a free and open source implementation of the IETF QUIC protocol written in C that is officially supported on the Microsoft Windows (including Server), Linux, and Xbox platforms. The project also provides libraries for macOS and Android, which are unsupported. It is designed to be a cross-platform general purpose QUIC library optimized for client and server applications benefitting from maximal throughput and minimal latency. By the end of 2021 the codebase had over 200,000 lines of production code, with 50,000 lines of "core" code, sharable across platforms. The source code is licensed under MIT License and available on GitHub.
Among its features are, in part, support for asynchronous IO, receive-side scaling (RSS), UDP send and receive coalescing, and connection migrations that persist connections between client and server to overcome client IP or port changes, such as when moving throughout mobile networks.
Both the HTTP/3 and SMB stacks of Microsoft Windows leverage MsQuic, with msquic.sys providing kernel-mode functionality. Being dependent upon Schannel for TLS 1.3, kernel mode therefore does not support 0-RTT.
User-mode programs can implement MsQuic, with support 0-RTT, through msquic.dll, which can be built from source code or downloaded as a shared library through binary releases on the repository.
Its support for the Microsoft Game Development Kit makes MsQuic possible on both Xbox and Windows.
See also
Transmission Control Protocol
User Datagram Protocol
HTTP/2
XDP for Windows
References
External links
MsQuic Performance Dashboard (Interactive)
MsQuic is Open Source
Making MsQuic Blazing Fast
Deploying HTTP/3 on Windows Server at Scale
C (programming language) libraries
Computer networking
Free and open-source software
Microsoft free software
Software using the MIT license
2019 software |
https://en.wikipedia.org/wiki/Doyle%20spiral | In the mathematics of circle packing, a Doyle spiral is a pattern of non-crossing circles in the plane in which each circle is surrounded by a ring of six tangent circles. These patterns contain spiral arms formed by circles linked through opposite points of tangency, with their centers on logarithmic spirals of three different shapes.
Doyle spirals are named after mathematician Peter G. Doyle, who made an important contribution to their mathematical construction in the late 1980s or However, their study in phyllotaxis (the mathematics of plant growth) dates back to the early
Definition
A Doyle spiral is defined to be a certain type of circle packing, consisting of infinitely many circles in the plane, with no two circles having overlapping interiors. In a Doyle spiral, each circle is enclosed by a ring of six other circles. The six surrounding circles are tangent to the central circle and to their two neighbors in the
Properties
Radii
As Doyle the only way to pack circles with the combinatorial structure of a Doyle spiral is to use circles whose radii are also highly For any such packing, there must exist three positive real numbers so that each circle of radius is surrounded by circles whose radii are (in cyclic order)
Only certain triples of numbers come from Doyle spirals; others correspond to systems of circles that eventually overlap each
Arms
In a Doyle spiral, one can group the circles into connecting chains of circles through opposite points of tangency. These have been called arms, following the same terminology used for Within each arm, the circles have radii in a doubly infinite geometric sequence
or a sequence of the same type with common multiplier In most Doyle spirals, the centers of the circles on a single arm lie on a logarithmic spiral, and all of the logarithmic spirals obtained in this way meet at a single central point. Some Doyle spirals instead have concentric circular arms (as in the stained glass window shown) or straig |
https://en.wikipedia.org/wiki/Human%20uses%20of%20scorpions | Humans use scorpions both practically, for medicine, food, and pets, and symbolically, whether as gods, to ward off harm, or to associate a product or business with the evident power of the small but deadly animal.
Practical uses
Medicine
Short-chain scorpion toxins constitute the largest group of potassium (K+) channel-blocking peptides. An important physiological role of the KCNA3 channel, also known as KV1.3, is to help maintain large electrical gradients for the sustained transport of ions such as Ca2+ that controls T lymphocyte (T cell) proliferation. Thus KV1.3 blockers could be potential immunosuppressants for the treatment of autoimmune disorders (such as rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis).
The venom of Uroplectes lineatus is clinically important in dermatology.
Several scorpion venom toxins have been investigated for medical use. Chlorotoxin from the deathstalker scorpion (Leiurus quinquestriatus); the toxin blocks small-conductance chloride channels; Maurotoxin from the venom of the Tunisian Scorpio maurus blocks potassium channels.
Some antimicrobial peptides in the venom of Mesobuthus eupeus; meucin-13 and meucin-18 have extensive cytolytic effects on bacteria, fungi, and yeasts, while meucin-24 and meucin-25 selectively kill Plasmodium falciparum and inhibit the development of Plasmodium berghei, both malaria parasites, but do not harm mammalian cells.
Food
Fried scorpion is traditionally eaten in Shandong, China.
As pets
Scorpions are sometimes kept as pets, in the same way as other dangerous animals like snakes and tarantula spiders. Popular Science Monthly carried an article entitled "My pet scorpion" as early as 1899.
Symbolic uses
Middle Eastern culture
The scorpion is a significant animal culturally, appearing as a motif in art, especially in Islamic art in the Middle East.
A scorpion motif is often woven into Turkish kilim flat-weave carpets, for protection from their sting. The scorpion is perce |
https://en.wikipedia.org/wiki/Qibla%20observation%20by%20shadows | Twice every year, the Sun culminates at the zenith of the Kaaba in Mecca, the holiest site in Islam, at local solar noon, allowing the qibla (the direction towards the Kaaba) to be ascertained in other parts of the world by observing the shadows cast by vertical objects. This phenomenon occurs at 12:18 Saudi Arabia Standard Time (SAST; 09:18 UTC) on 27 or 28 May (depending on the year), and at 12:27 SAST (09:27 UTC) on 15 or 16 July (depending on the year). At these times, the sun appears in the direction of Mecca, and shadows cast by vertical objects determine the qibla. At two other moments in the year, the sun passes through the nadir (the antipodal zenith) of the Kaaba, casting shadows that point in the opposite direction, and thus also determine the qibla. These occur on 12, 13, or 14 January at 00:30 SAST (21:30 UTC on the preceding day), and 28 or 29 November at 00:09 SAST (21:09 UTC on the preceding day).
The shadow points towards Mecca because the sun path makes the subsolar point travel through every latitude between the Tropic of Cancer and the Tropic of Capricorn every year, including the latitude of the Kaaba (21°25′N), and because the sun crosses the local meridian once a day. This observation has been known since at least the 13th century, when it was noted by the astronomers Jaghmini and Nasir al-Din al-Tusi, but their timings could not be fixed to a particular date because the Islamic calendar is lunar rather than solar; the solar date on which the sun culminates at the zenith of Mecca is constant, but the lunar date varies from year to year.
Context
Qibla
The qibla is the direction of the Kaaba, a cube-shaped building at the centre of the Great Mosque of Mecca (al-Masjid al-Haram) in the Hejaz region of Saudi Arabia. This direction is special in Islamic rituals and religious law because Muslims must face it during daily prayers (salat) and in other religious contexts. The determination of qibla was an important problem for Muslim communities |
https://en.wikipedia.org/wiki/Barcode%20library | Barcode library or Barcode SDK is a software library that can be used to add barcode features to desktop, web, mobile or embedded applications. Barcode library presents sets of subroutines or objects which allow to create barcode images and put them on surfaces or recognize machine-encoded text / data from scanned or captured by camera images with embedded barcodes. The library can support two modes: generation and recognition mode, some libraries support barcode reading and writing in the same way, but some libraries support only one mode.
At this time barcode technology allows to add machine reading tags or machine reading additional data to any object of real world with less than one cent cost. and use any of camera equipped device to identify additional data about an object. In this way, combination of barcode technology and barcode library allows to implement with low cost any automatic document processing application, OMR application, package tracking application or even augmented reality application.
History
The first Barcode SDKs were not implemented as software libraries but as standalone applications for DOS and Windows and as Barcode fonts. At that time barcodes were used mostly in retail and for internal corporation needs, thus barcode users looked for all-inclusive hardware solutions to generate, print and recognize barcodes.
The situation changed when camera equipped devices (like mobile phones) and document scanners became common for every day usage. Because barcodes could be scanned and recognized on common ordinary equipment and industrial and office users did not need to obtain expensive specialized one-function devices for barcode reading, the need for barcode writing and reading SDKs and libraries increased.
Barcode writing libraries already had been implemented as barcode fonts or standalone applications in projects like GNU Barcode or Zint. Implementation of a barcode writing library does not require hard Computer Science skills because |
https://en.wikipedia.org/wiki/Dynabook%20Inc. | , formerly Toshiba Client Solutions Co., Ltd., is a Japanese personal computer manufacturer owned by Sharp Corporation; it was owned by, and branded as, Toshiba from 1958 to 2018. It claims its Toshiba T1100, launched in 1985, as the first mass-market laptop PC. Toshiba had used "DynaBook" or "dynabook" as a sub-brand since 1989, but Dynabook became the worldwide brand in 2019.
, Dynabook Inc. had 162.9 billion yen (US$ billion) in annual sales and 2,680 employees; , Dynabook Americas described the business as being a "$60 billion global company employing nearly 200,000 in 30 countries".
History
The company began as Kawasaki Typewriter Co., Ltd. in 1954, but was bought by Tokyo Shibaura Electric Co., Ltd. (later Toshiba Corporation). Its name was changed to Toshiba Typewriter Co., Ltd. in 1958, Toshiba Business Machines Company in 1968, Toshiba Information Systems Corporation in 1984 after merging in Toshiba Business Computers Company, and Toshiba Client Solutions Co., Ltd. in 2016.
Toshiba era
The dynabook was a portable computer concept first introduced by Alan C. Kay in the 1960s and 1970s. Tetsuya Mizoguchi, an executive in Toshiba's mainframe computer division, read Kay's paper "Personal Dynamic Media" in the March 1977 IEEE Computer; and inspired by the concept of a computer that could be carried and used by anyone of any age, Mizoguchi became determined to develop such a computer.
The Dynabook trademark was already owned by other companies in Japan and the United States: Toshiba didn't use the name in the U.S., but ASCII Corporation had acquired the rights in Japan, so Toshiba paid a fee to ASCII to use the name there. The trademark rights in Britain, France, and West Germany were also able to be acquired.
The first Toshiba computer with the name DynaBook was announced on June 26, 1989. In August 1989, Mizoguchi sent a letter and a Toshiba DynaBook T1000SE to Kay in Boston, and in December Kay was Mizoguchi's guest at Toshiba. In 1990, the T1000SE |
https://en.wikipedia.org/wiki/IPadOS%2015 | iPadOS 15 is the third major release of the iPadOS operating system developed by Apple for its iPad line of tablet computers. The successor to iPadOS 14, it was announced at the company's Worldwide Developers Conference (WWDC) on June 7, 2021 along with iOS 15, macOS Monterey, watchOS 8, and tvOS 15. It was released to the public on September 20, 2021. It was succeeded by iPadOS 16, which was released on October 24, 2022.
iPadOS 15 is the final version of iPadOS that supports the iPad Air 2 and the iPad Mini 4, as its successor, iPadOS 16, drops support for those models.
Features
Home screen
The home screen grid is reduced by one row to accommodate the new widgets when placed (23 icons), and rotates in portrait orientation, just like iOS 12 and earlier.
Widgets
Widgets can now be placed directly anywhere on the home screen. There are more widgets, many of which now have a new fourth size to pick from, being extra-large.
App Library
iPadOS 15 introduces the App Library from the iPhone in iOS 14 to the iPad.
Multitasking
New multitasking user interface allows users to enter split view, slide over, enter full screen with quick gestures. The multiwindow shelf gives quick access to all running apps.
Quick Note
A new feature, called Quick Note, can be taken by swiping from the corner with fingers or the Apple Pencil, the Control Center or a keyboard shortcut.
Safari
Safari has been redesigned just like in iOS 15 and macOS Monterey. Safari has tab groups which allow the user to organize tabs into user-defined groups. Users can download third party extensions for Safari in the App Store.
Other
Universal Control allows a user to use a single keyboard and mouse across different Macs and iPads and new keyboard shortcuts have been added in iPadOS 15.4.
The Translate app is now available in iPadOS 15.
The iPadOS 13 default wallpapers were removed in the first beta of iPadOS 15.
iPadOS 15 features a new wallpaper in two modes: light and dark.
All models of iPad now have |
https://en.wikipedia.org/wiki/V1%20Saliency%20Hypothesis | The V1 Saliency Hypothesis, or V1SH (pronounced ‘vish’) is a theory about V1, the primary visual cortex (V1). It proposes that the V1 in primates creates a saliency map of the visual field to guide visual attention or gaze shifts exogenously.
Importance
V1SH is the only theory so far to not only endow V1 a very important cognitive function, but also to have provided multiple non-trivial theoretical predictions that have been experimentally confirmed subsequently. According to V1SH, V1 creates a saliency map from retinal inputs to guide visual attention or gaze shifts. Anatomically, V1 is the gate for retinal visual inputs to enter neocortex, and is also the largest cortical area devoted to vision. In the 1960s, David Hubel and Torsten Wiesel discovered that V1 neurons are activated by tiny image patches that are large enough to depict a small bar but not a discernible face. This work led to a Nobel prize, and V1 has since been seen as merely serving a back-office function (of image processing) for the subsequent cognitive processing in the brain beyond V1. However, research progress to understand the subsequent processing has been much more difficult or slower than expected (by, e.g., Hubel and Wiesel). Outside the box of the traditional views, V1SH is catalyzing a change of framework to enable fresh progresses on understanding vision.
See
for where primary visual cortex is in the brain and relative to the eyes.
V1SH states that V1 transforms the visual inputs into a saliency map of the visual field to guide visual attention or direction of gaze. Humans are essentially blind to visual inputs outside their window of attention. Therefore, attention gates visual perception and awareness, and theories of visual attention are cornerstones of theories of visual functions in the brain.
A saliency map is by definition computed from, or caused by, the external visual input rather than from internal factors such as animal’s expectations or goals (e.g., to read a book |
https://en.wikipedia.org/wiki/Coronavirus%20breathalyzer | A coronavirus breathalyzer is a diagnostic medical device enabling the user to test with 90% or greater accuracy the presence of severe acute respiratory syndrome coronavirus 2 in an exhaled breath.
As of the first half of 2020, the idea of a practical coronavirus breathalyzer was concomitantly developed by unrelated research groups in Australia, Canada, Finland, Germany, Indonesia, Israel, Netherlands, Poland, Singapore, United Kingdom and USA.
People with COVID-19 have higher levels of aldehydes, compounds produced when cells or tissues are damaged by inflammation, and ketones, which fits with research suggesting that the virus may damage the pancreas and cause ketosis. Diagnostics researchers hope to find the components in exhaled air that are truly characteristic of a disease and develop more specific sensors for them, This is done by studying breath samples using sensors in parallel with mass spectrometry analyses.
Different diseases may cause similar breath changes.
Diet can affect the chemicals someone exhales, as can smoking, alcohol consumption and medicines.
Australia
In Australia, GreyScan CEO Samantha Ollerton and Prof. Michael Breadmore of the University of Tasmania are basing a coronavirus breathalyzer on existing technology that is used around the world to detect explosives.
Canada
Canary Health Technologies, headquartered in Toronto with offices in Cleveland, Ohio, is developing a breathalyzer with disposable nanosensors using AI-powered cloud-based analysis. According to a press release, clinical trials began in India during November 2020. The stated goal is to develop an accurate, reasonably priced screening tool that can be used anywhere and deliver a result in less than a minute. The company postulates that analyzing volatile organic compounds in human breath could potentially detect diseases before the on-set of symptoms, earlier than currently available methods. Moreover, the cloud-based technology is designed to be used as a disease surv |
https://en.wikipedia.org/wiki/Journal%20of%20Spatial%20Science | The Journal of Spatial Science is an academic journal about spatial sciences published by Taylor & Francis on behalf of the Mapping Sciences Institute (Australia) and the Surveying and Spatial Sciences Institute.
It covers cartography, geodesy, geographic information science, hydrography, digital image analysis and photogrammetry, remote sensing, surveying and related areas.
Its editor-in-chief is Graeme Wright;
its 2018 impact factor is 1.711.
It started in 2004 as a continuation of both Cartography (1954-2003) and Australian Surveyor (1928-2003).
It also absorbed Geomatics Research Australasia (1995-2004), a continuation of the Australian Journal of Geodesy, Photogrammetry, and Surveying (1979-1994).
References
Academic journals associated with learned and professional societies of Australia
Taylor & Francis academic journals
Earth and atmospheric sciences journals
Remote sensing journals
Cartography journals
Geodesy
Hydrography
Photogrammetry
Surveying |
https://en.wikipedia.org/wiki/Marine%20Geodesy | Marine Geodesy is an academic journal published by Taylor & Francis about "ocean surveys, [ocean] mapping, and remote sensing".
Its editor-in-chief is Rongxing (Ron) Li;
its 2019 impact factor is 1.322.
References
Taylor & Francis academic journals
Oceanography journals
Remote sensing journals
Geodesy |
https://en.wikipedia.org/wiki/Survey%20Review | Survey Review is an academic journal published by Taylor & Francis about surveying.
It started in 1931 as Empire Survey Review and acquired the current name in 1963.
Its editor-in-chief is Peter Collier;
its 2018 impact factor is 1.442.
References
Taylor & Francis academic journals
Earth and atmospheric sciences journals
Engineering journals
Surveying |
https://en.wikipedia.org/wiki/Origami%20Polyhedra%20Design | Origami Polyhedra Design is a book on origami designs for constructing polyhedra. It was written by origami artist and mathematician John Montroll, and published in 2009 by A K Peters.
Topics
There are two traditional methods for making polyhedra out of paper: polyhedral nets and modular origami. In the net method, the faces of the polyhedron are placed to form an irregular shape on a flat sheet of paper, with some of these faces connected to each other within this shape; it is cut out and folded into the shape of the polyhedron, and the remaining pairs of faces are attached together. In the modular origami method, many similarly-shaped "modules" are each folded from a single sheet of origami paper, and then assembled to form a polyhedron, with pairs of modules connected by the insertion of a flap from one module into a slot in another module. This book does neither of those two things. Instead, it provides designs for folding polyhedra, each out of a single uncut sheet of origami paper.
After a brief introduction to the mathematics of polyhedra and the concepts used to design origami polyhedra, book presents designs for folding 72 different shapes, organized by their level of difficulty. These include the regular polygons and the Platonic solids, Archimedean solids, and Catalan solids, as well as less-symmetric convex polyhedra such as dipyramids and non-convex shapes such as a "sunken octahedron" (a compound of three mutually-perpendicular squares). An important constraint used in the designs was that the visible faces of each polyhedron should have few or no creases; additionally, the symmetries of the polyhedron should be reflected in the folding pattern, to the extent possible, and the resulting polyhedron should be large and stable.
Audience and reception
Reviewer Tom Hagedorn writes that "The book is well designed and organized and makes you want to start folding polyhedra," and that its instructions are "clear and easy to understand"; he recommends it to |
https://en.wikipedia.org/wiki/Gauss%20notation | Gauss notation (also known as a Gauss code or Gauss words) is a notation for mathematical knots. It is created by enumerating and classifying the crossings of an embedding of the knot in a plane. It is named after the German mathematician Carl Friedrich Gauss (1777–1855).
Gauss code represents a knot with a sequence of integers. However, rather than every crossing being represented by two different numbers, crossings are labelled with only one number. When the crossing is an overcrossing, a positive number is listed. At an undercrossing, a negative number.
For example, the trefoil knot in Gauss code can be given as: 1,−2,3,−1,2,−3.
Gauss code is limited in its ability to identify knots by a few problems. The starting point on the knot at which to begin tracing the crossings is arbitrary, and there is no way to determine which direction to trace in. Also, Gauss code is unable to indicate the handedness of each crossing, which is necessary to identify a knot versus its mirror. For example, the Gauss code for the trefoil knot does not specify if it is the right-handed or left-handed trefoil.
This last issue is often solved by using the extended Gauss code. In this modification, the positive/negative sign on the second instance of every number is chosen to represent the handedness of that crossing, rather than the over/under sign of the crossing, which is made clear in the first instance of the number. A right-handed crossing is given a positive number, and a left handed crossing is given a negative number.
References
See also
Conway notation (knot theory)
Dowker–Thistlethwaite notation
Mathematical notation
Knot theory
Carl Friedrich Gauss |
https://en.wikipedia.org/wiki/Unique%20Street%20Reference%20Number | The Unique Street Reference Number (USRN) is an eight-digit unique identifier (a geocode) for every street across Great Britain.
The USRNs for England and Wales exists within the National Street Gazetteer (NSG), the authoritative source of information about streets in England and Wales and is a compilation of data from 173 highway authorities' Local Street Gazetteers. The NSG is managed by GeoPlace as a joint venture between the Local Government Association and Ordnance Survey to create definitive national databases of addresses and streets.
USRNs in Scotland are managed by the Improvement Service, and in Northern Ireland by the Department for Infrastructure.
The USRN is available from the NSG and included in Ordnance Survey's OS MasterMap Highways Network product. USRNs can also be found on the site Find My Street created by GeoPlace.
From 1 July 2020, the Government requires USRNs and Unique Property Reference Numbers (UPRNs) to be available under an Open Government Licence (OGL). The OS Open USRN dataset is derived from the OS MasterMap Highways Network product.
The Government Digital Service has mandated the UPRN and USRN as "the public sector standard for referencing and sharing property and street information".
References
External links
Find My Street
Map of USRNs overlaid on OpenStreetMap data
Streets in the United Kingdom
Geocodes |
https://en.wikipedia.org/wiki/Tailscale | Tailscale Inc. is a software company based in Toronto, Canada. Tailscale develops a partially open-source software-defined mesh virtual private network (VPN) and a web-based management service. The company provides a zero config VPN as a service under the same name.
History
Founded in 2019 by Google engineers Avery Pennarun, David Crawshaw, David Carney, and Brad Fitzpatrick, the company secured funding of $12 million in a Series A round in November 2020 led by Accel with seed investors, Heavybit and Uncork Capital participating. In May 2022, the company became a Unicorn, raising a $100 million Series B round, led by CRV and Insight Partners, with participation from existing investors.
The company's name is inspired from a research paper The Tail at Scale published by Google.
Software
The open-source software acts in combination with the management service to establish peer-to-peer or relayed VPN communication with other clients using the WireGuard protocol. If the software fails to establish direct communication it falls back to using relays provided by the company. The IPv4 addresses given to clients are in the carrier-grade NAT reserved space. This was chosen to avoid interference with existing networks. The configuration also allows routing of traffic to networks behind the client on some clients.
See also
LogMeIn Hamachi
ZeroTier
Notes
References
External links
Virtual private network services
Mesh networking |
https://en.wikipedia.org/wiki/Atsukashiyama%20Barrier | The was a defensive fortification consisting of embankments and moats, erected in the late Heian period by the Northern Fujiwara in what is now the town of Kunimi, Fukushima in the Tōhoku region of Japan. It was the location of a major battle during the conquest of Hiraizumi by the forces of the Kamakura shogunate in 1189. The site was designated a National Historic Site of Japan in 1981.
Overview
The Atsukashiyama Barrier was a defensive structure built by Fujiwara no Kunihira, the son of Fujiwara no Yasuhira for the purpose of thwarting the invasion of Ōshū by the forces of Minamoto no Yoritomo in 1189. The embankment consisted of a triple set of earthen ramparts, protected by a double set of dry moats, yagura and siege crossbows, which extended for a three-kilometer length between the Atsukashi River and the Atsukashi Mountains. The location was a chokehold on the main route to northern Japan, and was identified by the Northern Fujiwara as critical for the defense of Hiraizumi. Even today the route of Japan National Route 4, the Tōhoku Expressway and the Tōhoku Main Line railway must pass through this gap.
Although one of the largest and most impressive structures of its kind attempted in Japan, Atsukashiyama Barrier only stalled the Minamoto advance for a short period, and Fujiwara Kunihira was killed in the battle.
The site came to scholarly attention during construction work on the Tōhoku Expressway in 1971, although its location was clearly stated in the medieval Azuma Kagami chronicle. Despite the significance of the site, the Fukushima Prefectural government planned a large-scale land improvement project would have effectively destroyed all trace of the ruins. The Fukushima Prefectural Board of Education conducted a rescue archaeology excavation at nine locations along the embankment in 1979, finding numerous artifacts and discovering that the moats had a width of 15 meters, and depth of 1.5 meters in shallow places, and 2.8 meters in deep places. |
https://en.wikipedia.org/wiki/PKCS%207 | In cryptography, "PKCS #7: Cryptographic Message Syntax" (a.k.a. "CMS") is a standard syntax for storing signed and/or encrypted data. PKCS #7 is one of the family of standards called Public-Key Cryptography Standards (PKCS) created by RSA Laboratories. The latest version, 1.5, is available as RFC 2315.
An update to PKCS #7 is described in RFC 2630, which was replaced in turn by RFC 3369, RFC 3852 and then by RFC 5652.
PKCS #7 files may be stored both as raw DER format or as PEM format. PEM format is the same as DER format but wrapped inside Base64 encoding and sandwiched in between and . Windows uses the ".p7b" file name extension for both these encodings.
A typical use of a PKCS #7 file would be to store certificates and/or certificate revocation lists (CRL).
Here's an example of how to first download a certificate, then wrap it inside a PKCS #7 archive and then read from that archive:
$ echo '' | openssl s_client -connect example.org:443 -host example.org 2>/dev/null | openssl x509 > example.org.cer 2>/dev/null
$ openssl crl2pkcs7 -nocrl -certfile example.org.cer -out example.org.cer.pem.p7b
$ openssl pkcs7 -in example.org.cer.pem.p7b -noout -print_certs
subject=C = US, ST = California, L = Los Angeles, O = Internet Corporation for Assigned Names and Numbers, OU = Technology, CN = www.example.org issuer=C = US, O = DigiCert Inc, CN = DigiCert SHA2 Secure Server CA
References
External links
Man page for openssl-pkcs7
Cryptography standards |
https://en.wikipedia.org/wiki/Collabora%20Online | Collabora Online is an open source online office suite built on LibreOffice Technology, enabling web-based collaborative real-time editing of word processing documents, spreadsheets, presentations, and vector graphics. Optional apps are available for desktops, laptops, tablets, smartphones and Chromebooks.
Collabora Online is developed by Collabora Productivity, a division of Collabora, who are a commercial partner with LibreOffice's parent organisation The Document Foundation (TDF). The TDF states that a majority of the LibreOffice software development is done by its commercial partners, Collabora, Red Hat, CIB, and Allotropia.
Features
Collabora Online can be accessed from modern web browsers without plug-ins or add-ons, documents, spreadsheets, presentations and vector graphics can be edited collaboratively.
Collaborative functions include comments which other users can respond to, document version history which enables the comparison of documents and restoring, etc. Collaborative functions may also include integrated video calls or chat whilst collaboratively editing documents, features like these are possible with integrations with enterprise cloud solutions such as Nextcloud, ownCloud, Seafile, EGroupware and others. Collabora Online can be integrated with any application.
Device support
Client apps are not required to access Collabora Online which only needs a web browser; However, optional apps are available for most devices that run the following operating systems: Android, ChromeOS, iOS, iPadOS, Windows, macOS and Linux.
These optional apps share the same LibreOffice Technology core software with Collabora Online, this results with document fidelity between them. Software coding development therefore normally effects the source code of Collabora Online all of the apps simultaneously. The apps work offline without the need for a connection to a local server or the cloud, support for integrations with cloud storage services is still possible. The mobi |
https://en.wikipedia.org/wiki/Worms%20Rumble | Worms Rumble is a 2020 action game developed and published by Team17. As a spin-off of the long-running Worms series, the game was released for Microsoft Windows, PlayStation 4 and PlayStation 5 in December 2020 and for the Nintendo Switch, Xbox One and Xbox Series X/S in June 2021.
Gameplay
Unlike its predecessors, Worms Rumble is a 2.5D real-time action game. In Rumble, players assume control of anthropomorphic worms and compete against each other in modes including Death Match, Last Worm Standing and Last Squad Standing. The game features a variety of exotic weapons, such as Sheep Launchers, Plasma Blasters, and Sentry Turrets, which can be used to defeat enemies. Players can also acquire jet packs and grappling hooks to navigate the environment easily. As players progress in the game, they can also gain experience points which can be used to unlock cosmetic items and customise the appearance of their playable avatars.
Development
Team17 announced Worms Rumble on July 3, 2020 to celebrate the 25th anniversary of the Worms series. It is the first game in the series since Worms W.M.D (2016). The game is envisioned to be a spin-off rather than a mainline installment in the franchise, as it replaces the series' traditional turn-based artillery gameplay with real-time combat. An open beta for the game was released on November 6, 2020. The game was released for Windows, PlayStation 4 and PlayStation 5 on December 1, 2020 with cross-platform play enabled. Team17 has announced that the ports of Worms Rumble for Nintendo Switch, Xbox One and Xbox Series X/S are planned for a 2021 release. The new versions were released on June 23, 2021 and include platform-exclusive costumes. The game was added to the Xbox Game Pass service on the same date, with physical editions for all platforms to follow on July 13, 2021.
Reception
According to review aggregator Metacritic, the game received mixed or average reviews. Christian Donlan from Eurogamer called the game "a hectic real-ti |
https://en.wikipedia.org/wiki/Read-mostly%20memory | Read-mostly memory (RMM) is a type of memory that can be read fast, but written to only slowly.
Historically, the term was used to refer to different types of memory over time:
In 1970, it was used by Intel and Energy Conversion Devices to refer to a new type of amorphous and crystalline nonvolatile and reprogrammable semiconductor memory (phase-change memory aka PCM/PRAM). However, it was also used to refer to reprogrammable memory (REPROM) and magnetic-core memory.
The term has mostly fallen into disuse, but is sometimes used referring to electrically erasable programmable read-only (EEPROM) or flash memory today.
See also
Read-only memory (ROM)
Read-write memory (R/W)
Programmable read-only memory (PROM)
Random access memory (RAM)
References
Further reading
Non-volatile memory
Computer memory |
https://en.wikipedia.org/wiki/Net%2025%20Tower | The Net 25 tower is a free-standing lattice tower with a triangular cross-section used by Net 25 a Philippine television network based out of Quezon City. Built-in the year 2000, the tower stands tall.
It is currently the second tallest structure in the Philippines and one of the tallest lattice towers in the world. Its transmitter transmits the signals of Net 25 (DZEC-TV), INCTV 48 (DZCE-TV) & Eagle FM 95.5 (DWDM-FM).
See also
Lattice tower
List of tallest freestanding steel structures
References
External links
http://www.eaglebroadcasting.net/dzec/
Lattice towers
Towers completed in 2000
Broadcast transmitters
Buildings and structures in Quezon City
Transmitter sites in the Philippines |
https://en.wikipedia.org/wiki/Deficiency%20%28graph%20theory%29 | Deficiency is a concept in graph theory that is used to refine various theorems related to perfect matching in graphs, such as Hall's marriage theorem. This was first studied by Øystein Ore. A related property is surplus.
Definition of deficiency
Let be a graph, and let U be an independent set of vertices, that is, U is a subset of V in which no two vertices are connected by an edge. Let denotes the set of neighbors of U, which is formed by all vertices from 'V' that are connected by an edge to one or more vertices of U. The deficiency of the set U is defined by:
Suppose G is a bipartite graph, with bipartition V = X ∪ Y. The deficiency of G with respect to one of its parts (say X), is the maximum deficiency of a subset of X:
Sometimes this quantity is called the critical difference of G.
Note that defG of the empty subset is 0, so def(G;X) ≥ 0.
Deficiency and matchings
If def(G;X) = 0, it means that for all subsets U of X, |NG(U)| ≥ |U|. Hence, by Hall's marriage theorem, G admits a perfect matching.
In contrast, if def(G;X) > 0, it means that for some subsets U of X, |NG(U)| < |U|. Hence, by the same theorem, G does not admit a perfect matching. Moreover, using the notion of deficiency, it is possible to state a quantitative version of Hall's theorem:
Proof. Let d = def(G;X). This means that, for every subset U of X, |NG(U)| ≥ |U|-d. Add d dummy vertices to Y, and connect every dummy vertex to all vertices of X. After the addition, for every subset U of X, |NG(U)| ≥ |U|. By Hall's marriage theorem, the new graph admits a matching in which all vertices of X are matched. Now, restore the original graph by removing the d dummy vertices; this leaves at most d vertices of X unmatched.
This theorem can be equivalently stated as:
where ν(G) is the size of a maximum matching in G (called the matching number of G).
Properties of the deficiency function
In a bipartite graph G = (X+Y, E), the deficiency function is a supermodular set function: for every t |
https://en.wikipedia.org/wiki/A%20Treatise%20on%20the%20Circle%20and%20the%20Sphere | A Treatise on the Circle and the Sphere is a mathematics book on circles, spheres, and inversive geometry. It was written by Julian Coolidge, and published by the Clarendon Press in 1916. The Chelsea Publishing Company published a corrected reprint in 1971, and after the American Mathematical Society acquired Chelsea Publishing it was reprinted again in 1997.
Topics
As is now standard in inversive geometry, the book extends the Euclidean plane to its one-point compactification, and considers Euclidean lines to be a degenerate case of circles, passing through the point at infinity. It identifies every circle with the inversion through it, and studies circle inversions as a group, the group of Möbius transformations of the extended plane. Another key tool used by the book are the "tetracyclic coordinates" of a circle, quadruples of complex numbers describing the circle in the complex plane as the solutions to the equation . It applies similar methods in three dimensions to identify spheres (and planes as degenerate spheres) with the inversions through them, and to coordinatize spheres by "pentacyclic coordinates".
Other topics described in the book include:
Tangent circles and pencils of circles
Steiner chains, rings of circles tangent to two given circles
Ptolemy's theorem on the sides and diagonals of quadrilaterals inscribed in circles
Triangle geometry, and circles associated with triangles, including the nine-point circle, Brocard circle, and Lemoine circle
The Problem of Apollonius on constructing a circle tangent to three given circles, and the Malfatti problem of constructing three mutually-tangent circles, each tangent to two sides of a given triangle
The work of Wilhelm Fiedler on "cyclography", constructions involving circles and spheres
The Mohr–Mascheroni theorem, that in straightedge and compass constructions, it is possible to use only the compass
Laguerre transformations, analogues of Möbius transformations for oriented projective geometry
Dupin cyc |
https://en.wikipedia.org/wiki/80%20Million%20Tiny%20Images | 80 Million Tiny Images is a dataset intended for training machine learning systems. It contains 79,302,017 32×32 pixel color images, scaled down from images extracted from the World Wide Web in 2008 using automated web search queries on a set of 75,062 non-abstract nouns derived from WordNet. The words in the search terms were then used as labels for the images. The researchers used seven web search resources for this purpose: Altavista, Ask.com, Flickr, Cydral, Google, Picsearch and Webshots.
The 80 Million Tiny Images dataset was retired from use by its creators in 2020, after a paper by researchers Abeba Birhane and Vinay Prabhu found that some of the labeling of several publicly available image datasets, including 80 Million Tiny Images, was causing models trained on them to exhibit racial and sexual bias. They have asked other researchers not to use it for further research and to delete their copies of the dataset.
The CIFAR-10 dataset uses a subset of the images in this dataset, but with independently generated labels.
References
Machine learning
Datasets in computer vision |
https://en.wikipedia.org/wiki/Genetic%20resources%20conservation%20and%20sustainable%20use | Genetic resources means genetic material of actual or potential value where genetic material means any material of plant, animal, microbial or other origin containing functional units of heredity... Genetic resources thus refer to the part of genetic diversity that has or could have practical use, such as in plant breeding. The term was introduced by Otto Frankel and Erna Bennett for a technical conference on the exploration, utilization and conservation of plant genetic resources, organized by the Food and Agriculture Organisation (FAO) and the International Biological Program (IBP), held in Rome, Italy, 18–26 September 1967.
Before the introduction of the term, the Russian scientist Nikolai Vavilov initiated comprehensive studies on plant genetic resources and conservation work in the 1920’s. The American botanist Jack Harlan stressed the tight link between plant genetic resources and man in a seminal publication "Crops and Man".
Genetic resources is one of the three levels of biodiversity defined by Article 2 of the Convention on Biological Diversity (CBD) in Rio, 1992
Under the CBD, discussions and negotiations regarding genetic resources are organized by the FAO Commission of Genetic Resources for Food and Agriculture. This commission distinguishes the following domains of genetic resources:
Animal genetic resources
Aquatic genetic resources
Forest genetic resources
Micro-organisms and invertebrates
Plant genetic resources
Genetic resources are threatened by genetic erosion and conservation activities are undertaken to prevent loss of diversity.
Methodologies for conservation of genetic resources
There are two complementary ways to conserve genetics resources:
in situ, which consists in managing populations on-site, dynamically evolving in their natural environment. In situ methodologies include:
conservation in natural populations (in nature)
on farm conservation
ex situ, which consists in conserving individuals or populations out of their na |
https://en.wikipedia.org/wiki/Al-Fatihin%20Magazine | Al-Fatihin () was a magazine in the Indonesian language published by the Islamic State and released by AlFurat Media Center.
See also
Dabiq (magazine)
Rumiyah (magazine)
References
Defunct political magazines
Irregularly published magazines
Islamic magazines
Islamic State of Iraq and the Levant and Russia
Magazines disestablished in 2017
Magazines established in 2016
News magazines published in Asia
Online magazines
Indonesian-language magazines
Defunct magazines published in Indonesia |
https://en.wikipedia.org/wiki/EncroChat | EncroChat was a Europe-based communications network and service provider that offered modified smartphones allowing encrypted communication among subscribers. It was used primarily by organized crime members to plan criminal activities. Police infiltrated the network between at least March and June 2020 during a Europe-wide investigation. An unidentified source associated with EncroChat announced on the night of 12–13 June 2020 that the company would cease operations because of the police operation.
The service had around 60,000 subscribers at the time of its closure. As a result of police being able to read unencrypted EncroChat messages, at least 1,000 arrests had been made across Europe as of 22 December 2020.
Background
EncroChat handsets emerged in 2016 as a replacement for a previously disabled end-to-end encrypted service. The company had revealed on 31 December 2015 the Version 115 of EncroChat OS, which appears to be the first public release of their operating system. The earliest version of the company's website archived by the Wayback Machine dates to 23 September 2015.
According to a May 2019 report by the Gloucester Citizen, EncroChat was originally developed for "celebrities who feared their phone conversations were being hacked". In the 2015 murder of English mobster Paul Massey, the killers used a similar service providing encrypted BlackBerry phones based on PGP. After the Dutch and Canadian police compromised their server in 2016, EncroChat turned into a popular alternative among criminals for its security-oriented services in 2017–2018.
The founders and owners of EncroChat are not known. According to Dutch journalist Jan Meeus, a Dutch organized crime gang was involved and financed the developers.
Through a marketing strategy of "relentless online advertising", EncroChat rapidly expanded during its four and a half years of existence, benefiting from the closure of its competitors PGP Safe and Ennetcom. The network eventually reached an estima |
https://en.wikipedia.org/wiki/George%20Bedborough | George Bedborough Higgs (10 January 1868 – 7 August 1940) was an English bookseller, journalist and writer who advocated for a number of causes, including sex reform, freethought, secularism, eugenics, animal rights, vegetarianism, and free love. He was the secretary of the Legitimation League and editor of the League's publication The Adult: A Journal for the Advancement of freedom in Sexual Relationships. Bedborough was convicted for obscenity in 1898, after being caught selling a book on homosexuality; the case of Regina v. Bedborough, has also been referred to as the Bedborough trial or Bedborough case.
Biography
Early life and education
George Bedborough Higgs was born in St Giles, London, on 10 January 1868. His father was a retired Church of England preacher and his mother was a poet. He was educated at Dulwich College and began work at the age of 16, founding the Workhouse Aid Society with W. T. Stead. Bedborough later attended university.
In 1887, Bedborough was present at Bloody Sunday, in Trafalgar Square. He later wrote for a number of publications including the Sunday Chronicle, Shafts (a feminist magazine), University Magazine, the Newcastle Weekly Chronicle and South London Mail. Bedborough was a close friend and collaborator with Henry S. Salt, Bertram Dobell and Ernest Bell.
From 1891 to 1892, Bedborough was a member of the National Society of Lanternists. He also occasionally worked as a lantern operator and gave lectures.
Bedborough was a member of the Legitimation League and edited its journal The Adult between 1897 and 1898; the League advocated for the legitimation of illegitimate children and free love. He married for the sake of his family and had an open relationship with his wife Louie. She was the treasurer of the League.
Regina v. Bedborough
On 31 May 1898, Bedborough was arrested, along with the sex-radical feminist Lillian Harman and charged with obscenity for attempting to "corrupt the morals of Her Majesty's Subjects". He was |
https://en.wikipedia.org/wiki/Wikifunctions | Wikifunctions is a collaboratively edited catalog of computer functions to enable the creation, modification, and reuse of source code. It is closely related to Abstract Wikipedia, an extension of Wikidata to create a language-independent version of Wikipedia using its structured data. Provisionally named Wikilambda, the definitive name of Wikifunctions was announced on 22 December 2020 following a naming contest. Wikifunctions is the first Wikimedia project to launch since Wikidata in 2012.
After three years of development, Wikifunctions officially launched in July 2023.
References
External links
Project overview on Meta-Wiki
Project updates on Meta-Wiki
Computer-related introductions in 2023
Creative Commons-licensed websites
Internet properties established in 2023
Semantic Web
Wikidata
Wikimedia projects
Source code |
https://en.wikipedia.org/wiki/Algorithmic%20Puzzles | Algorithmic Puzzles is a book of puzzles based on computational thinking. It was written by computer scientists Anany and Maria Levitin, and published in 2011 by Oxford University Press.
Topics
The book begins with a "tutorial" introducing classical algorithm design techniques including backtracking, divide-and-conquer algorithms, and dynamic programming, methods for the analysis of algorithms, and their application in example puzzles. The puzzles themselves are grouped into three sets of 50 puzzles, in increasing order of difficulty. A final two chapters provide brief hints and more detailed solutions to the puzzles, with the solutions forming the majority of pages of the book.
Some of the puzzles are well known classics, some are variations of known puzzles making them more algorithmic, and some are new. They include:
Puzzles involving chessboards, including the eight queens puzzle, knight's tours, and the mutilated chessboard problem
Balance puzzles
River crossing puzzles
The Tower of Hanoi
Finding the missing element in a data stream
The geometric median problem for Manhattan distance
Audience and reception
The puzzles in the book cover a wide range of difficulty, and in general do not require more than a high school level of mathematical background.
William Gasarch notes that grouping the puzzles only by their difficulty and not by their themes is actually an advantage, as it provides readers with fewer clues about their solutions.
Reviewer Narayanan Narayanan recommends the book to any puzzle aficionado, or to anyone who wants to develop their powers of algorithmic thinking. Reviewer Martin Griffiths suggests another group of readers, schoolteachers and university instructors in search of examples to illustrate the power of algorithmic thinking.
Gasarch recommends the book to any computer scientist, evaluating it as "a delight".
References
Algorithms
Puzzle books
2011 non-fiction books
Oxford University Press books |
https://en.wikipedia.org/wiki/Clario%20Tech | Clario is a security software development company that offers consumer-facing digital security and privacy applications for use on a range of operating systems including iOS, Android, macOS.
Clario Tech allegedly has more than 800 team members in various worldwide locations, the majority appear to be operating from Ukraine. The workforce consists of software developers, marketing specialists, security researchers and customer support agents. In 2019, the company announced it would invest $30 million during 2020 to develop its cybersecurity products and make them accessible for all.
Products
Clario
Clario security application was officially launched at the Consumer Electronic Awards in January 2020 in Las Vegas. Clario announced its aim was to offer a new online security product via a user-friendly dashboard, integrating cybersecurity technology with 24/7 human support against digital threats.
The cybersecurity application has been reviewed in various publications including the Evening Standard who called it the “Uber of cybersecurity”.
In response to the COVID-19 pandemic, Clario launched a 24/7 IT support hotline for anyone to call if they experienced technology issues while in lockdown. The company's 600+ team were on hand to respond to any reported issues.
Clario received the AV-TEST certification in December 2020 and was featured in the honorable mentions list in the Privacy Focused tool nomination as part of the Product Hunt's 2020 Golden Kitty Award Winners in 2020.
MacUpdate
MacUpdate is a Macintosh software download website founded in 1997 by Joel Mueller. In 2017, the site was sold to Zeobit, and subsequently was acquired by Clario Tech in 2020.
MacKeeper
MacKeeper is utility software that offers system cleaning, privacy features and antivirus for macOS. Clario Tech has become the owner of the MacKeeper software since 2019 with aim to accelerate the transformation of MacKeeper.
Clario cybersecurity research
Clario Tech has undertaken numerous p |
https://en.wikipedia.org/wiki/QuarantineChat | QuarantineChat is a multilingual voice-based social networking service launched on March 1, 2020, by multimedia artists Danielle Baskin and Max Hawkins. The service is part of Dialup, an application with the same premise. The service is made for people to stay connected with other people amid the COVID-19 pandemic at select times during the day. As of late April 2020, it has reported to have more than 15,000 users.
History
Hawkins developed an early iteration of the service in 2012 named Call in the Night, that connects people in the same time zones between 2 a.m. and 5 a.m. for "conversations about dreams." Baskin and Hawkins met at a Halloween party, where Baskin gave Hawkins a tarot reading. According to Baskin, the reading said that they were interested in "phone stuff," which possibly prompted Hawkins to share his idea. In 2019, they launched the app Dialup.
A year later, as COVID-19 spread rapidly in China, Hawkins' girlfriend talked about boredom while staying at home, which prompted Hawkins and Baskin to create QuarantineChat. The service was then launched on March 1. She hopes that the service "brings magic and serendipity to a new reality where thousands of people are stuck inside alone for the next month." Baskin, via Business Insider Australia, said that the purpose of the service is to "unify people using humour."
Usage was then noticed in Iran, Hong Kong, Portugal, and London, with the most users based on time zones are in the Pacific and Iran Standard Time. As of March 11, there were 70 users detected, with the number increasing to 15,000 on May 27.
Technique
Users register their phone numbers via the QuarantineChat website. They then download the Dialup app via the App Store or Play Store, depending on their mobile device's operating system (OS). Once users open the app and redeem the invitation given, an alert will pop up, explaining how the service works. Users can also select conversation themes, so that the system can connect users of the s |
https://en.wikipedia.org/wiki/Advanced%20Matrix%20Extensions | Advanced Matrix Extensions (AMX), also known as Intel Advanced Matrix Extensions (Intel AMX), are extensions to the x86 instruction set architecture (ISA) for microprocessors from Intel designed to work on matrices to accelerate artificial intelligence (AI) / machine learning (ML) -related workloads.
Extensions
AMX was introduced by Intel in June 2020 and first supported by Intel with the Sapphire Rapids microarchitecture for Xeon servers, released in January 2023. It introduced 2-dimensional registers called tiles upon which accelerators can perform operations. It is intended as an extensible architecture; the first accelerator implemented is called tile matrix multiply unit (TMUL).
In Intel Architecture Instruction Set Extensions and Future Features revision 46, published in September 2022, a new AMX-FP16 extension was documented. This extension adds support for half-precision floating-point numbers. In revision 48 from March 2023, AMX-COMPLEX was documented, adding support for half-precision floating-point complex numbers. Both extensions are planned for inclusion in the future Granite Rapids processors (AMX-COMPLEX - only in Granite Rapids-D).
Tile matrix multiply unit
TMUL unit supports BF16 and INT8 input types. AMX-FP16 also adds support for FP16 numbers and AMX-COMPLEX - for FP16 complex numbers, where a pair of adjacent FP16 numbers represent real and imaginary parts of the complex number. The register file consists of 8 tiles, each with 16 rows of size of 64 bytes (32 BF16/FP16 or 64 INT8 elements). The only supported operation as for now is matrix multiplication
Ops/cycle per core:
Intel AMX-INT8: 2048 (=16 * 64 * 2)
Intel AMX-BF16: 1024 (=16 * 32 * 2)
Software support
Compiler and assembler support
LLVM 13
GCC 11
GNU Assembler (GAS) initial support committed at 25 June 2020
Operating system support
glibc support for detecting AMX feature in CPUs committed at 25 June 2020
Linux kernel support released in version 5.16
VMware vSphere support fo |
https://en.wikipedia.org/wiki/How%20Round%20Is%20Your%20Circle%3F | How Round Is Your Circle? Where Engineering and Mathematics Meet is a book on the mathematics of physical objects, for a popular audience. It was written by chemical engineer John Bryant and mathematics educator Chris Sangwin, and published by the Princeton University Press in 2008.
Topics
The book has 13 chapters, whose topics include:
Lines, the thickness of physically drawn or cut lines, and the problem of testing straightness of physical objects
The construction of physical measuring and calculating devices including rulers, protractors, pantographs, planimeters, integrators, and slide rules
Mechanical linkages, pantographs, four-bar linkages, and the problem of converting rotary to linear motion, solved by the Peaucellier–Lipkin linkage and by Hart's inversor
Geometric dissections, straightedge and compass constructions, angle trisection, and mathematical origami
The catenary and the tractrix, curves formed from physical forces, and their use in bridges and bearings
Approximation by rational numbers, discretization and pixelization, gear ratios, and the approximations involved in calendar systems
The roundness of objects, non-circular objects of constant width, including the Reuleaux triangle and certain coins, and their use in drilling square holes
Stability and mechanical equilibrium of objects, overhanging objects and the block-stacking problem, supereggs, and objects with only one stable resting position (unfortunately not including the Gömböc, which was discovered too recently to be included)
The book emphasizes the construction of physical models, and includes many plates of the authors' own models, detailed construction plans, and illustrations.
Audience and reception
Doug Manchester characterizes the topic of the book as "recreational engineering". It only requires a standard background in mathematics including basic geometry, trigonometry, and a small amount of calculus. Owen Smith calls it "a great book for engineers and mathematicians, as well as t |
https://en.wikipedia.org/wiki/Applications%20of%20sensitivity%20analysis%20in%20epidemiology | Sensitivity analysis studies the relation between the uncertainty and the uncertainties in the model assumptions. Sensitivity analysis can play an important role in epidemiology, for example in assessing the influence of the unmeasured confounding on the causal conclusions of a study. It is also important in all mathematical modelling studies of epidemics.
Sensitivity analysis can be used in epidemiology, for example in assessing the influence of the unmeasured confounding on the causal conclusions of a study. The use of sensitivity analysis in mathematical modelling of infectious disease is suggested in on the Coronavirus disease 2019 outbreak. Given the significant uncertainty at play, the use of sensitivity analysis to apportion the output uncertainty into input parameters is crucial in the context of Decision-making. Examples of applications of sensitivity analysis to modelling of COVID-19 are and. in particular, the time of intervention time in containing the pandemic spread is identified as a key parameter.
References
Mathematical modeling
Mathematical analysis
Epidemiology |
https://en.wikipedia.org/wiki/Video%20imprint%20%28computer%20vision%29 | Proposed as an extension of image epitomes in the field of video content analysis, video imprint is obtained by recasting video contents into a fixed-sized tensor representation regardless of video resolution or duration. Specifically, statistical characteristics are retained to some degrees so that common video recognition tasks can be carried out directly on such imprints, e.g., event retrieval, temporal action localization. It is claimed that both spatio-temporal interdependences are accounted for and redundancies are mitigated during the computation of video imprints.
The option of computing video imprints exploiting the epitome model has the advantage of more flexible input feature formats and more efficient training stage for video content analysis.
See also
Epitome (data processing)
Image epitomes
References
Data processing
Image processing
Computer vision |
https://en.wikipedia.org/wiki/TL431 | The TL431 integrated circuit (IC) is a three-terminal adjustable precise shunt voltage regulator. With the use of an external voltage divider, a TL431 can regulate voltages ranging from 2.495 to 36 V, at currents up 100 mA. The typical initial deviation of reference voltage from the nominal 2.495 V level is measured in millivolts, the maximum worst-case deviation is measured in tens of millivolts. The circuit can control power transistors directly; combinations of the TL431 with power MOS transistors are used in high efficiency, very low dropout linear regulators. The TL431 is the de facto industry standard error amplifier circuit for switched-mode power supplies with optoelectronic coupling of the input and output networks.
Texas Instruments introduced the TL431 in 1977. In the 21st century, the original TL431 remains in production along with a multitude of clones and derivatives (TLV431, TL432, ATL431, KA431, LM431, TS431, 142ЕН19 and others). These functionally similar circuits may differ considerably in die size and layout, precision and speed characteristics, minimal operating currents, safe operating areas, and specific voltage reference.
Construction and operation
The TL431 is functionally equivalent to an ideal npn bipolar transistor switch with a stable 2.495 V switching threshold and no apparent hysteresis. "Base", "collector" and "emitter" of this "transistor" are traditionally called reference (R or REF), cathode (C) and anode (A). The positive control voltage, VREF, is applied between reference input and the anode; the output current, ICA, flows from the cathode to the anode.
On a functional level the TL431 contains an open-loop operational amplifier that compares the input control voltage with a 2.495 V voltage reference. This, however, is merely an abstraction: both functions are inextricably linked inside the TL431's front end. There is no physical 2.495 V source: the actual internal reference is provided by a 1.2 V Widlar bandgap (transistors T |
https://en.wikipedia.org/wiki/Basic%20Number%20Theory | Basic Number Theory is an influential book by André Weil, an exposition of algebraic number theory and class field theory with particular emphasis on valuation-theoretic methods. Based in part on a course taught at Princeton University in 1961-2, it appeared as Volume 144 in Springer's Grundlehren der mathematischen Wissenschaften series. The approach handles all 'A-fields' or global fields, meaning finite algebraic extensions of the field of rational numbers and of the field of rational functions of one variable with a finite field of constants. The theory is developed in a uniform way, starting with topological fields, properties of Haar measure on locally compact fields, the main theorems of adelic and idelic number theory, and class field theory via the theory of simple algebras over local and global fields. The word `basic’ in the title is closer in meaning to `foundational’ rather than `elementary’, and is perhaps best interpreted as meaning that the material developed is foundational for the development of the theories of automorphic forms, representation theory of algebraic groups, and more advanced topics in algebraic number theory. The style is austere, with a narrow concentration on a logically coherent development of the theory required, and essentially no examples.
Mathematical context and purpose
In the foreword, the author explains that instead of the “futile and impossible task” of improving on Hecke’s classical treatment of algebraic number theory, he “rather tried to draw the conclusions from the developments of the last thirty years, whereby locally compact groups, measure and integration have been seen to play an increasingly important role in classical number theory”. Weil goes on to explain a viewpoint that grew from work of Hensel, Hasse, Chevalley, Artin, Iwasawa, Tate, and Tamagawa in which the real numbers may be seen as but one of infinitely many different completions of the rationals, with no logical reason to favour it over the various |
https://en.wikipedia.org/wiki/PHP%20serialization%20format | The PHP serialization format is the serialization format used by the PHP programming language. The format can serialize PHP's primitive and compound types, and also properly serializes references. The format was first introduced in PHP 4.
In addition to PHP, the format is also used by some third-party applications that are often integrated with PHP applications, for example by Lucene/Solr.
Syntax
The syntax generally follows the pattern of one-letter code of the variable type, followed by a colon and the length of the data, followed by the variable value, and ending with a semicolon.
References
External links
PHP Scripts
PHP: Serialize
PHP
Data serialization formats |
https://en.wikipedia.org/wiki/Icons%20of%20Mathematics | Icons of Mathematics: An Exploration of Twenty Key Images is a book on elementary geometry for a popular audience. It was written by Roger B. Nelsen and Claudi Alsina, and published by the Mathematical Association of America in 2011 as volume 45 of their Dolciani Mathematical Expositions book series.
Topics
Each of the book's 20 chapters begins with an iconic mathematical diagram, and discusses an interrelated set of topics inspired by that diagram, including results in geometry, their proofs and visual demonstrations, background material, biographies of mathematicians, historical illustrations and quotations, and connections to real-world applications.
The topics include:
The geometry of circles and triangles, star polygons, Platonic solids, and figurate numbers
The Pythagorean theorem, Thales's theorem on right triangles in semicircles, and geometric interpretations of the arithmetic mean, geometric mean, and harmonic mean
Dido's problem on surrounding as large an area as possible with a given perimeter, and curves of constant width
Tessellations, polygon triangulations, and rep-tiles
Similar figures and spirals
The mathematics of the yin and yang symbol and other self-complementary shapes, and of tatami arrangements.
Audience and reception
Reviewer E. J. Barbeau recommends the book to high-school level mathematics students and teachers. Cheryl McAllister suggests it as auxiliary material for both high school and general-audience college mathematics courses, and Hans-Wolfgang Henn adds that it also makes enjoyable light reading for professional mathematicians.
References
Elementary geometry
Popular mathematics books
2011 non-fiction books
Mathematical Association of America |
https://en.wikipedia.org/wiki/Matrix%20factorization%20of%20a%20polynomial | In mathematics, a matrix factorization of a polynomial is a technique for factoring irreducible polynomials with matrices. David Eisenbud proved that every multivariate real-valued polynomial p without linear terms can be written as a AB = pI, where A and B are square matrices and I is the identity matrix. Given the polynomial p, the matrices A and B can be found by elementary methods.
Example:
The polynomial x2 + y2 is irreducible over R[x,y], but can be written as
References
External links
A Mathematica implementation of a algorithm to matrix-factorize polynomials
Polynomials
Algebra
Polynomials factorization algorithms |
https://en.wikipedia.org/wiki/Hiroshi%20Fujita | (born 7 December 1928 in Osaka) is a retired Japanese mathematician who worked in partial differential equations. He obtained his Ph.D. at the University of Tokyo, under the supervision of Tosio Kato.
Mathematical contributions
His most widely cited paper, published in 1966, studied the partial differential equation
and showed that there is a "threshold" value for which implies the existence of nonconstant solutions which exist for all positive and all real values of the variables. By contrast, if is between and then such solutions cannot exist. This paper initiated the study of similar and analogous phenomena for various parabolic and hyperbolic partial differential equations. The impact of Fujita's paper is described by the well-known survey articles of Levine (1990) and Deng & Levine (2000).
In collaboration with Kato, Fujita applied the semigroup approach in evolutionary partial differential equations to the Navier–Stokes equations of fluid mechanics. They found the existence of unique locally defined strong solutions under certain fractional derivative-based assumptions on the initial velocity. Their approach has been adopted by other influential works, such as Giga & Miyakawa (1985), to allow for different assumptions on the initial velocity. The full understanding of the smoothness and maximal extension of such solutions is currently considered as a major problem of partial differential equations and mathematical physics.
Selected publications
Tosio Kato and Hiroshi Fujita. On the nonstationary Navier-Stokes system. Rend. Sem. Mat. Univ. Padova 32 (1962), 243–260.
Hiroshi Fujita and Tosio Kato. On the Navier-Stokes initial value problem. I. Arch. Rational Mech. Anal. 16 (1964), 269–315.
Hiroshi Fujita. On the blowing up of solutions of the Cauchy problem for . J. Fac. Sci. Univ. Tokyo Sect. I 13 (1966), 109–124.
Mathematical theory of sedimentation analysis (book)
Functional-Analytic Methods for Partial Differential Equations (1990, Springer), |
https://en.wikipedia.org/wiki/Burt%27s%20solar%20compass | Burt's solar compass or astronomical compass/sun compass is a surveying instrument that makes use of the Sun's direction instead of magnetism. William Austin Burt invented his solar compass in 1835. The solar compass works on the principle that the direction to the Sun at a specified time can be calculated if the position of the observer on the surface of the Earth is known, to a similar precision. The direction can be described in terms of the angle of the Sun relative to the axis of rotation of the planet.
This angle is made up of the angle due to latitude, combined with the angle due to the season, and the angle due to the time of day. These angles are set on the compass for a chosen time of day, the compass base is set up level using the spirit levels provided, and then the sights are aligned with the Sun at the specified time, so the image of the Sun is projected onto the cross grating target. At this point the compass base will be aligned true north–south. It is then locked in place in this alignment, after which the sighting arms can be rotated to align with any landmark or beacon, and the direction can be read off the verniers as an angle relative to true north.
This device avoided the problems of the normal magnetic compass used by surveyors, which displayed erratic readings when in a locality of high iron ore content and inconsistent and unknown local magnetic variation. The instrument was found to be so accurate that it was the choice of the United States government when surveying public lands, state boundaries, and railroad routes. It won awards from various organizations and was used by surveyors from the nineteenth into the twentieth century.
History
Burt became a United States deputy surveyor in 1833 and began surveying government land for a territory northwest of the Ohio River. By 1834, he and his surveying crew were surveying territory in the lower peninsula of Michigan. He was surveying land in the upper peninsula of Michigan by 1835 to be use |
https://en.wikipedia.org/wiki/Nepal%20Engineering%20Council | Nepal Engineering Council is an autonomous government body formed on 11 March 1999 under The Nepal Engineering Council Act. The council was established in order to mobilize the engineering profession in a systematic and scientific manner by making it effective, as well as to make provision for, among other matters, the registration of the names of engineers as per their qualifications.
The council used to register engineers based on academic certificates until 2022. An amendment bill was registered in the parliament in June 2019 and was passed in August 2022 which makes mandatory to take exams from the council to get license. As of 2022, there are 37 engineering field for which license are issued.
Councilors
Nepal Engineering Council has 21 Councilors as follows:
Chairman appointed by the government of Nepal
Vice Chairman appointed by the government of Nepal
Five engineers appointed by the government of Nepal
President of Nepal Engineers Association
Seven engineers elected from Nepal Engineering Association
One representative from Institute of Engineering, Tribhuvan University
One campus chief from various engineering colleges
Registrar
Three members elected by the council
Jurisdiction of Council
Licensing (Registration) of Engineers
Accreditation of certificates of academic qualifications
Recognition of the academic institutions
Professional code of conduct
Registration Category
The council has provision to register Engineers in three categories:
General Engineer ( Category - A )
Professional Engineer ( Category - B )
Foreign Engineer ( Category - C )
See also
Nepal Bar Council
Nepal Medical Council
References
External links
Education in Nepal
Organisations based in Nepal
Regulatory agencies of Nepal
1999 establishments in Nepal
Engineering organizations in Nepal |
https://en.wikipedia.org/wiki/Character%20computing | Character computing is a trans-disciplinary field of research at the intersection of computer science and psychology. It is any computing that incorporates the human character within its context. Character is defined as all features or characteristics defining an individual and guiding their behavior in a specific situation. It consists of stable trait markers (e.g., personality, background, history, socio-economic embeddings, culture,...) and variable state markers (emotions, health, cognitive state, ...). Character computing aims at providing a holistic psychologically-driven model of human behavior. It models and predicts behavior based on the relationships between a situation and character. Three main research modules fall under the umbrella of character computing: character sensing and profiling, character-aware adaptive systems, and artificial characters.
Overview
Character computing can be viewed as an extension of the well-established field of affective computing. Based on the foundations of the different psychology branches, it advocates defining behavior as a compound attribute that is not driven by either personality, emotions, situation or cognition alone. It rather defines behavior as a function of everything that makes up an individual i.e., their character and the situation they are in. Affective computing aims at allowing machines to understand and translate the non-verbal cues of individuals into affect. Accordingly, character computing aims at understanding the character attributes of an individual and the situation to translate it to predicted behavior, and vice versa.
''In practical terms, depending on the application context, character computing is a branch of research that deals with the design of systems and interfaces that can observe, sense, predict, adapt to, affect, understand, or simulate the following: character based on behavior and situation, behavior based on character and situation, or situation based on character and behavior.'' |
https://en.wikipedia.org/wiki/Vladimir%20Varyukhin | Vladimir Alekseevich Varyukhin (December 14, 1921 — July 8, 2007) was a Soviet and Ukrainian scientist, Professor, Doctor of Technical Sciences, Honored Scientist of the Ukrainian SSR, Major-General, founder of the theory of multichannel analysis, and creator of the scientific school on digital antenna arrays (DAAs).
Scientific results
In 1962, he founded the well-known scientific school on multichannel analysis and digital antenna arrays. The theory of multichannel analysis that was developed by him considers the methods of determination of the angular coordinates of sources as functions of the angular distances between the sources and the phase and energy relations between signals and gives the basis for the functional schemes of units realizing the theoretical conclusions. The determination of the parameters of sources is carried on by the direct solution of systems of high-order transcendental equations describing the response function of a multichannel analyzer. In this case, the super-Rayleigh resolution of the sources of signals is ensured. The difficulties arising at the solution of the transcendental systems of high-order equations were overcome by V. A. Varyukhin by means of the “separation” of the unknowns, at which the determination of angular coordinates is reduced to the solution of algebraic equations, and the complex amplitudes are found by the solution of the linear systems of equations of the N-th order.
The Interdepartmental scientific-technical meeting organized in 1977 by the Scientific Council of the USSR Academy of Sciences on the problem “Statistical radiophysics” (Chairman — Academician Yuri Kobzarev) dated officially the start of the studies performed under the guidance of V. A. Varyukhin in the trend of digital antenna arrays by 1962 and recognized the priority of Varyukhin's scientific school in the development and practical realization of the theory of multichannel analysis.
In the subsequent years, V. A. Varyukhin supervised a numbe |
https://en.wikipedia.org/wiki/Thermal%20pressure | In thermodynamics, thermal pressure (also known as the thermal pressure coefficient) is a measure of the relative pressure change of a fluid or a solid as a response to a temperature change at constant volume. The concept is related to the Pressure-Temperature Law, also known as Amontons's law or Gay-Lussac's law.
In general pressure, () can be written as the following sum: .
is the pressure required to compress the material from its volume to volume at a constant temperature . The second term expresses the change in thermal pressure . This is the pressure change at constant volume due to the temperature difference between and . Thus, it is the pressure change along an isochore of the material.
The thermal pressure is customarily expressed in its simple form as
Thermodynamic definition
Because of the equivalences between many properties and derivatives within thermodynamics (e.g., see Maxwell Relations), there are many formulations of the thermal pressure coefficient, which are equally valid, leading to distinct yet correct interpretations of its meaning.
Some formulations for the thermal pressure coefficient include:
Where is the volume thermal expansion, the isothermal bulk modulus, the Grüneisen parameter, the compressibility and the constant-volume heat capacity.
Details of the calculation:
The utility of the thermal pressure
The thermal pressure coefficient can be considered as a fundamental property; it is closely related to various properties such as internal pressure, sonic velocity, the entropy of melting, isothermal compressibility, isobaric expansibility, phase transition, etc. Thus, the study of the thermal pressure coefficient provides a useful basis for understanding the nature of liquid and solid. Since it is normally difficult to obtain the properties by thermodynamic and statistical mechanics methods due to complex interactions among molecules, experimental methods attract much attention.
The thermal pressure coefficient is used |
https://en.wikipedia.org/wiki/Visvalingam%E2%80%93Whyatt%20algorithm | The Visvalingam–Whyatt algorithm, also known as the Visvalingam's algorithm, is an algorithm that decimates a curve composed of line segments to a similar curve with fewer points.
Idea
Given a polygonal chain (often called a Polyline), the algorithm attempts to find a similar chain composed of fewer points.
Points are assigned an importance based on local conditions, and points are removed from the least important to most important.
In Visvalingam's algorithm, the importance is related to the triangular area added by each point.
Algorithm
Given a chain of 2d points , the importance of each interior point is computed by finding the area of the triangle formed by it and its immediate neighbors. This can be done quickly using a matrix determinant. Alternatively, the equivalent formula below can be used
The minimum importance point is located and marked for removal (note that and will need to be recomputed). This process is repeated until either the desired number of points is reached, or the contribution of the least important point is large enough to not neglect.
Advantages
The algorithm is easy to understand and explain, but is often competitive with much more complex approaches.
With the use of a priority queue, the algorithm is performant on large inputs, since the importance of each point can be computed using only its neighbors, and removing a point only requires recomputing the importance of two other points.
It is simple to generalize to higher dimensions, since the area of the triangle between points has a consistent meaning.
Disadvantages
The algorithm does not differentiate between sharp spikes and shallow features, meaning that it will clean up sharp spikes that may be important.
The algorithm simplifies the entire length of the curve evenly, meaning that curves with high and low detail areas will likely have their fine details eroded.
See also
Curve fitting
Alternative algorithms for line simplification include:
Ramer–Dougla |
https://en.wikipedia.org/wiki/Thomas%20Goodwillie%20%28mathematician%29 | Thomas G. Goodwillie (born 1954) is an American mathematician and professor at Brown University who has made fundamental contributions to algebraic and geometric topology. He is especially famous for developing the concept of calculus of functors, often also named Goodwillie calculus.
Life
While studying at Harvard University, Goodwillie became a Putnam Fellow in 1974 and 1975. He then studied at Princeton University, where he completed his PhD at in 1982, under the supervision of Wu-Chung Hsiang. He returned to Harvard as Junior Fellow in 1979, and was an associate professor (without tenure) at Harvard from 1982 to 1987. In 1987 he was hired with tenure by Brown University, where he was promoted to full professor in 1991.
He developed the calculus of functors in a series of three papers in the 1990s and 2000s, which has since been expanded and applied in a number of areas, including the theory of smooth manifolds, algebraic K-theory, and homotopy theory.
He has advised 11 PhD students.
Goodwillie is interested in issues of racial and gender equality and has taught a course on this topic. He is an active user on MathOverflow.
Recognition
Goodwillie received a Sloan Fellowship and the Harriet S. Sheridan Award. He is a Fellow of the American Mathematical Society.
A conference with leading topologists as speakers was organized on the occasion of his 60th birthday.
References
External links
Website at Brown University
Topologists
20th-century American mathematicians
21st-century American mathematicians
Harvard University alumni
Princeton University alumni
Harvard University Department of Mathematics faculty
Harvard University faculty
Brown University faculty
1954 births
Living people
Fellows of the American Mathematical Society
Putnam Fellows |
https://en.wikipedia.org/wiki/Ethics%20of%20quantification | Ethics of quantification is the study of the ethical issues associated to different forms of visible or invisible forms of quantification. These could include algorithms, metrics/ indicators, statistical and mathematical modelling, as noted in a review of various aspects of sociology of quantification.
According to Espeland and Stevens an ethics of quantification would naturally descend from a sociology of quantification, especially at an age where democracy, merit, participation, accountability and even ‘‘fairness’’ are assumed to be best discovered and appreciated via numbers. In his classic work Trust in Numbers Theodore M. Porter notes how numbers meet a demand for quantified objectivity, and may for this be by used by bureaucracies or institutions to gain legitimacy and epistemic authority.
For Andy Stirling of the STEPS Centre at Sussex University there is a rhetoric element around concepts such as ‘expected utility’, ‘decision theory’, ‘life cycle assessment’, ‘ecosystem services’ ‘sound scientific decisions’ and ‘evidence-based policy’. The instrumental application of these techniques and their use of quantification to deliver an impression of accuracy may raise ethical concerns.
For Sheila Jasanoff these technologies of quantification can be labeled as 'Technologies of hubris', whose function is to reassure the public while keeping the wheels of science and industry turning. The downside of the technologies of hubris is that they may generate overconfidence thanks to the appearance of exhaustivity; they can preempt a political discussion by transforming a political problem into a technical one; and remain fundamentally limited in processing what takes place outside their restricted range of assumptions.
Jasanoff contrasts technologies of hubris with 'technologies of humility' which admit the existence of ambiguity, indeterminacy and complexity, and strive to bring to the surface the ethical nature of problems. Technologies of humility are also sensit |
https://en.wikipedia.org/wiki/Photokinesis | Photokinesis is a change in the velocity of movement of an organism as a result of changes in light intensity. The alteration in speed is independent of the direction from which the light is shining. Photokinesis is described as positive if the velocity of travel is greater with an increase in light intensity and negative if the velocity is slower. If a group of organisms with a positive photokinetic response is swimming in a partially shaded environment, there will be fewer organisms per unit of volume in the sunlit portion than in the shaded parts. This may be beneficial for the organisms if it is unfavourable to their predators, or it may be propitious to them in their quest for prey.
In photosynthetic prokaryotes, the mechanism for photokinesis appears to be an energetic process. In cyanobacteria, for example, an increase in illumination results in an increase of photophosphorylation which enables an increase in metabolic activity. However the behaviour is also found among eukaryotic microorganisms, including those like Astasia longa which are not photosynthetic, and in these, the mechanism is not fully understood. In Euglena gracilis, the rate of swimming has been shown to speed up with increased light intensity until the light reaches a certain saturation level, beyond which the swimming rate declines.
The sea slug Discodoris boholiensis also displays positive photokinesis; it is nocturnal and moves slowly at night, but much faster when caught in the open during daylight hours. Moving faster in the exposed environment should reduce predation and enable it to conceal itself as soon as possible, but its brain is quite incapable of working this out. Photokinesis is common in tunicate larvae, which accumulate in areas with low light intensity just before settlement, and the behaviour is also present in juvenile fish such as sockeye salmon smolts.
See also
Kinesis (biology)
Phototaxis
Phototropism
References
Biology terminology |
https://en.wikipedia.org/wiki/Wheels%2C%20Life%20and%20Other%20Mathematical%20Amusements | Wheels, Life and Other Mathematical Amusements is a book by Martin Gardner published in 1983. The Basic Library List Committee of the Mathematical Association of America has recommended its inclusion in undergraduate mathematics libraries.
Contents
Wheels, Life and Other Mathematical Amusements is a book of 22 mathematical games columns that were revised and extended after being previously published in Scientific American. It is Gardner's 10th collection of columns, and includes material on Conway's Game of Life, supertasks, intransitive dice, braided polyhedra, combinatorial game theory, the Collatz conjecture, mathematical card tricks, and Diophantine equations such as Fermat's Last Theorem.
Reception
Dave Langford reviewed Wheels, Life and Other Mathematical Amusements for White Dwarf #55, and stated that "Here too are revisions of the three famous pieces on Conway's solitaire game Life, which has absorbed several National Debts' worth of computer time since 1970. Fascinating." The book was positively reviewed in several other mathematics and science journals.
References
Books about mathematics
Works by Martin Gardner |
https://en.wikipedia.org/wiki/Homotopy%20associative%20algebra | In mathematics, an algebra such as has multiplication whose associativity is well-defined on the nose. This means for any real numbers we have
.
But, there are algebras which are not necessarily associative, meaning if then
in general. There is a notion of algebras, called -algebras, which still have a property on the multiplication which still acts like the first relation, meaning associativity holds, but only holds up to a homotopy, which is a way to say after an operation "compressing" the information in the algebra, the multiplication is associative. This means although we get something which looks like the second equation, the one of inequality, we actually get equality after "compressing" the information in the algebra.
The study of -algebras is a subset of homotopical algebra, where there is a homotopical notion of associative algebras through a differential graded algebra with a multiplication operation and a series of higher homotopies giving the failure for the multiplication to be associative. Loosely, an -algebra is a -graded vector space over a field with a series of operations on the -th tensor powers of . The corresponds to a chain complex differential, is the multiplication map, and the higher are a measure of the failure of associativity of the . When looking at the underlying cohomology algebra , the map should be an associative map. Then, these higher maps should be interpreted as higher homotopies, where is the failure of to be associative, is the failure for to be higher associative, and so forth. Their structure was originally discovered by Jim Stasheff while studying A∞-spaces, but this was interpreted as a purely algebraic structure later on. These are spaces equipped with maps that are associative only up to homotopy, and the A∞ structure keeps track of these homotopies, homotopies of homotopies, and so forth.
They are ubiquitous in homological mirror symmetry because of their necessity in defining the structure of the Fu |
https://en.wikipedia.org/wiki/Berlekamp%20switching%20game | The Berlekamp switching game is a mathematical game proposed by American mathematician Elwyn Berlekamp. It has also been called the Gale–Berlekamp switching game, after David Gale, who discovered the same game independently, or the unbalancing lights game. It involves a system of lightbulbs controlled by two banks of switches, with one game player trying to turn many lightbulbs on and the other trying to keep as many as possible off. It can be used to demonstrate the concept of covering radius in coding theory.
Rules
The equipment for playing the game consists of a room containing rectangular array of lightbulbs, of dimensions for some numbers and . A bank of switches on one side of the room controls each lightbulb individually. Flipping one of these switches changes its lightbulb from off to on or from on to off, depending on its previous state. On the other side of the room is another bank of switches, one for each row or column of lightbulbs. Whenever any of these switches is flipped, every lightbulb in the row or column that it controls changes from off to on or from on to off, depending on its previous state. When flipping more than one switch, the order in which the switches are flipped does not make a difference to the outcome: the same lightbulbs will be lit at the end of the sequence of flips no matter what order they are flipped.
The game is played in two rounds. In the first round, the first player uses the switches that control individual lights, to set the lights on or off arbitrarily. In the second round, the second player uses the switches that control rows or columns of lights, changing the pattern of lights set by the first player into another pattern (or, possibly, leaving it unchanged). The goal of the first player is to have as many lights remaining lit at the end of the game as possible, and the goal of the second player is to have as few lights remaining lit as possible. Therefore, the first player should choose a pattern of lights for w |
https://en.wikipedia.org/wiki/List%20of%20keyboard%20switches |
Commonly used mechanical switches on pre-built keyboards
Manufacturers frequently build computer keyboards using switches from original equipment manufacturers (OEMs). The switches used determine the feel of the keyboard.
Mechanical keyboard switches for custom keyboards
On the custom mechanical keyboard space, there are far greater quantity of keyboard switches. It is important to note that these do not portray the diversity and number of switches currently on the market.
Future
As time goes on, there are more and more switches being developed and manufactured across the world. Some are by new manufacturers, some are collaborations between companies and manufacturers, and some are consumer made. Some bigger databases that involve more than just our main manufacturers listed here.
On top of a variety of new switches being made, consumers are taking parts of different switches and then going on to make their own switches, called “Franken-switches.”
References
Computer keyboards
Keyboard switches |
https://en.wikipedia.org/wiki/Triller%20%28app%29 | Triller is an American video-sharing social networking service. The service allows users to create and share short-form videos, including videos set to, or automatically synchronized to music using artificial intelligence technology. Triller was released for iOS and Android in 2015, and initially operated as a video editing app before adding social networking features.
In mid-2020, the app gained prominence in India and the United States as a competitor to the similar Chinese-owned app TikTok, after the service was banned in India, and faced the threat of a ban in the U.S. Triller later expanded into sports promotion, distributing pay-per-view boxing events between Mike Tyson and Roy Jones Jr. and Jake Paul and Ben Askren, both incorporating appearances by internet, sports, music, and entertainment personalities.
History
Triller was launched in 2015 by co-founders David Leiberman and Sammy Rubin. The app was originally positioned as a video editor, using artificial intelligence to automatically edit distinct clips into music videos. They later launched Triller Famous, a page within the app that featured curated selections of user videos. In 2016, the app was purchased by Carnegie Technologies and converted into a social networking service by allowing users to follow each other and share their videos publicly. In 2019, Ryan Kavanaugh's Proxima Media made a majority investment. It is headquartered in Los Angeles, California, and is currently led by CEO Mahi de Silva.
On June 29, 2020, Government of India banned TikTok, among other apps stating that they were "prejudicial to [the] sovereignty and integrity" of India. Triller, which had planned to enter into the Indian market by the end of 2020, saw a spike from less than 1 million users to over 30 million users in the country overnight. In July 2020, Triller sued ByteDance, the Chinese parent company of TikTok, for infringing patents relating to video editing.
In August 2020, U.S. president Donald Trump signed an |
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