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Arrow (symbol)
An arrow is a graphical symbol, such as ← or →, or a pictogram, used to point or indicate direction. In its simplest form, an arrow is a triangle, chevron, or concave kite, usually affixed to a line segment or rectangle, and in more complex forms a representation of an actual arrow (e.g. ➵ U+27B5). The direction indicated by an arrow is the one along the length of the line or rectangle toward the single pointed end. History An older (medieval) convention is the manicule (pointing hand, 👈). Pedro Reinel in c. 1504 first used the fleur-de-lis as indicating north in a compass rose; the convention of marking the eastern direction with a cross is older (medieval). Use of the arrow symbol does not appear to pre-date the 18th century. An early arrow symbol is found in an illustration of Bernard Forest de Bélidor's treatise ''L'architecture hydraulique'', printed in France in 1737. The arrow is here used to illustrate the direction of the flow of water and of the water w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrows In Okazaki
Arrows may refer to: * more than one arrow * Arrows (Australian band), indie rock band established 2006 * Arrows (British band), 1970s Anglo-American glam rock-pop band * Arrows (Unicode block), a Unicode block containing line, curve, and semicircle symbols terminating in barbs or arrows ** Also in the topic of Unicode: ** Arrows in Unicode ** Miscellaneous Symbols and Arrows (Unicode block) ** Supplemental Arrows-A (Unicode block) ** Supplemental Arrows-B (Unicode block) ** Supplemental Arrows-C (Unicode block) * "Arrows" (song), 2014 song by Fences featuring Macklemore and produced by Ryan Lewis * "Arrows" (Foo Fighters song), from the 2017 album '' Concrete and Gold'' * "Arrows", a song by Fireworks from their 2011 album ''Gospel'' * ''Arrows'' (Stonegard album), 2006 * ''Arrows'' (The Lonely Forest album), 2011 * ''Arrows'' (TV series), Arrows pop band's 1976-7 weekly ITV TV series * Arrows Grand Prix International, defunct Formula One team See also * Arrow (disambigu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Hilbert
David Hilbert (; ; 23 January 1862 – 14 February 1943) was a German mathematician, one of the most influential mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas in many areas, including invariant theory, the calculus of variations, commutative algebra, algebraic number theory, the foundations of geometry, spectral theory of operators and its application to integral equations, mathematical physics, and the foundations of mathematics (particularly proof theory). Hilbert adopted and defended Georg Cantor's set theory and transfinite numbers. In 1900, he presented a collection of problems that set the course for much of the mathematical research of the 20th century. Hilbert and his students contributed significantly to establishing rigor and developed important tools used in modern mathematical physics. Hilbert is known as one of the founders of proof theory and mathematical logic. Life Early life and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexadecimal
In mathematics and computing, the hexadecimal (also base-16 or simply hex) numeral system is a positional numeral system that represents numbers using a radix (base) of 16. Unlike the decimal system representing numbers using 10 symbols, hexadecimal uses 16 distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9, and "A"–"F" (or alternatively "a"–"f") to represent values from 10 to 15. Software developers and system designers widely use hexadecimal numbers because they provide a human-friendly representation of binary-coded values. Each hexadecimal digit represents four bits (binary digits), also known as a nibble (or nybble). For example, an 8-bit byte can have values ranging from 00000000 to 11111111 in binary form, which can be conveniently represented as 00 to FF in hexadecimal. In mathematics, a subscript is typically used to specify the base. For example, the decimal value would be expressed in hexadecimal as . In programming, a number o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unicode
Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, which is maintained by the Unicode Consortium, defines as of the current version (15.0) 149,186 characters covering 161 modern and historic scripts, as well as symbols, emoji (including in colors), and non-visual control and formatting codes. Unicode's success at unifying character sets has led to its widespread and predominant use in the internationalization and localization of computer software. The standard has been implemented in many recent technologies, including modern operating systems, XML, and most modern programming languages. The Unicode character repertoire is synchronized with ISO/IEC 10646, each being code-for-code identical with the other. ''The Unicode Standard'', however, includes more than just the base code. Along ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NAND Operator
In Boolean functions and propositional calculus, the Sheffer stroke denotes a logical operation that is equivalent to the negation of the conjunction operation, expressed in ordinary language as "not both". It is also called nand ("not and") or the alternative denial, since it says in effect that at least one of its operands is false. In digital electronics, it corresponds to the NAND gate. It is named after Henry M. Sheffer and written as ↑ or as , (but not as , , , often used to represent disjunction). In Bocheński notation it can be written as D''pq''. Its dual is the NOR operator (also known as the Peirce arrow or Quine dagger). Like its dual, NAND can be used by itself, without any other logical operator, to constitute a logical formal system (making NAND functionally complete). This property makes the NAND gate crucial to modern digital electronics, including its use in computer processor design. Definition The NAND operation is a logical operation on two log ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
If And Only If
In logic and related fields such as mathematics and philosophy, "if and only if" (shortened as "iff") is a biconditional logical connective between statements, where either both statements are true or both are false. The connective is biconditional (a statement of material equivalence), and can be likened to the standard material conditional ("only if", equal to "if ... then") combined with its reverse ("if"); hence the name. The result is that the truth of either one of the connected statements requires the truth of the other (i.e. either both statements are true, or both are false), though it is controversial whether the connective thus defined is properly rendered by the English "if and only if"—with its pre-existing meaning. For example, ''P if and only if Q'' means that ''P'' is true whenever ''Q'' is true, and the only case in which ''P'' is true is if ''Q'' is also true, whereas in the case of ''P if Q'', there could be other scenarios where ''P'' is true and ''Q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematical Logic
Mathematical logic is the study of formal logic within mathematics. Major subareas include model theory, proof theory, set theory, and recursion theory. Research in mathematical logic commonly addresses the mathematical properties of formal systems of logic such as their expressive or deductive power. However, it can also include uses of logic to characterize correct mathematical reasoning or to establish foundations of mathematics. Since its inception, mathematical logic has both contributed to and been motivated by the study of foundations of mathematics. This study began in the late 19th century with the development of axiomatic frameworks for geometry, arithmetic, and analysis. In the early 20th century it was shaped by David Hilbert's program to prove the consistency of foundational theories. Results of Kurt Gödel, Gerhard Gentzen, and others provided partial resolution to the program, and clarified the issues involved in proving consistency. Work in set theory sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road Surface Marking
Road surface marking is any kind of device or material that is used on a road surface in order to convey official information; they are commonly placed with road marking machines (also referred to as road marking equipment or pavement marking equipment). They can also be applied in other facilities used by vehicles to mark parking spaces or designate areas for other uses. In some countries and areas (France, Italy, Czech Republic, Slovakia etc.), road markings are conceived as horizontal traffic signs, as opposed to vertical traffic signs placed on posts. Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians. Uniformity of the markings is an important factor in minimizing confusion and uncertainty about their meaning, and efforts exist to standardize such markings across borders. However, countries and areas categorize and specify road surface markings in different ways—white lines are called white lines mechanical, non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wayfinding
Wayfinding (or way-finding) encompasses all of the ways in which people (and animals) orient themselves in physical space and navigate from place to place. Wayfinding software is a self-service computer program that helps users to find a location, usually used indoors and installed on interactive kiosks or smartphones. Basic process The basic process of wayfinding involves four stages: # ''Orientation'' is the attempt to determine one's location, in relation to objects that may be nearby and the desired destination. # ''Route decision'' is the selection of a course of direction to the destination. # ''Route monitoring'' is checking to make sure that the selected route is heading towards the destination. # ''Destination recognition'' is when the destination is recognized. Historical Historically, wayfinding refers to the techniques used by travelers over land and sea to find relatively unmarked and often mislabeled routes. These include but are not limited to dead reckoning, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signage
Signage is the design or use of signs and symbols to communicate a message. A signage also means signs ''collectively'' or being considered as a group. The term ''signage'' is documented to have been popularized in 1975 to 1980. Signs are any kind of visual graphics created to display information to a particular audience. This is typically manifested in the form of wayfinding information in places such as streets or on the inside and outside buildings. Signs vary in form and size based on location and intent, from more expansive banners, billboards, and murals, to smaller street signs, street name signs, sandwich boards and lawn signs. Newer signs may also use digital or electronic displays. The main purpose of signs is to communicate, to convey information designed to assist the receiver with decision-making based on the information provided. Alternatively, promotional signage may be designed to persuade receivers of the merits of a given product or service. Signage is d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire Exit
An emergency exit in a structure is a special exit for emergencies such as a fire: the combined use of regular and special exits allows for faster evacuation, while it also provides an alternative if the route to the regular exit is blocked. The qualifications for an emergency exit are as follows: it must be in a location that is easily accessible, the exit must have an area or location that it can bring people to in the event of any emergency, it must be controlled by the inside of the building, it must be well managed and regularly up kept, and it must be in a permanent location. It is usually in a strategically located (e.g. in a stairwell, hallway, or other likely places) outward opening door with a crash bar on it and with exit signs leading to it. The name is a reference to when they were frequently used, however, a fire exit can also be a main doorway must be able to be unlocked from the inside of the room. A fire escape is a special kind of emergency exit, mounted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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