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[SOURCE: https://en.wikipedia.org/wiki/Bipartite_graph] | [TOKENS: 3207] |
Contents Bipartite graph In the mathematical field of graph theory, a bipartite graph (or bigraph) is a graph whose vertices can be divided into two disjoint and independent sets U {\displaystyle U} and V {\displaystyle V} , that is, every edge connects a vertex in U {\displaystyle U} to one in V {\displaystyle V} . Vertex sets U {\displaystyle U} and V {\displaystyle V} are usually called the parts of the graph. Equivalently, a bipartite graph is a graph that does not contain any odd-length cycles. The two sets U {\displaystyle U} and V {\displaystyle V} may be thought of as a coloring of the graph with two colors: if one colors all nodes in U {\displaystyle U} blue, and all nodes in V {\displaystyle V} red, each edge has endpoints of differing colors, as is required in the graph coloring problem. In contrast, such a coloring is impossible in the case of a non-bipartite graph, such as a triangle: after one node is colored blue and another red, the third vertex of the triangle is connected to vertices of both colors, preventing it from being assigned either color. One often writes G = ( U , V , E ) {\displaystyle G=(U,V,E)} to denote a bipartite graph whose partition has the parts U {\displaystyle U} and V {\displaystyle V} , with E {\displaystyle E} denoting the edges of the graph. If a bipartite graph is not connected, it may have more than one bipartition; in this case, the ( U , V , E ) {\displaystyle (U,V,E)} notation is helpful in specifying one particular bipartition that may be of importance in an application. If | U | = | V | {\displaystyle |U|=|V|} , that is, if the two subsets have equal cardinality, then G {\displaystyle G} is called a balanced bipartite graph. If all vertices on the same side of the bipartition have the same degree, then G {\displaystyle G} is called biregular. Examples When modelling relations between two different classes of objects, bipartite graphs very often arise naturally. For instance, a graph of football players and clubs, with an edge between a player and a club if the player has played for that club, is a natural example of an affiliation network, a type of bipartite graph used in social network analysis. Another example where bipartite graphs appear naturally is in the (NP-complete) railway optimization problem, in which the input is a schedule of trains and their stops, and the goal is to find a set of train stations as small as possible such that every train visits at least one of the chosen stations. This problem can be modeled as a dominating set problem in a bipartite graph that has a vertex for each train and each station and an edge for each pair of a station and a train that stops at that station. More abstract examples include the following: Properties Bipartite graphs may be characterized in several different ways: In bipartite graphs, the size of minimum vertex cover is equal to the size of the maximum matching; this is Kőnig's theorem. An alternative and equivalent form of this theorem is that the size of the maximum independent set plus the size of the maximum matching is equal to the number of vertices. In any graph without isolated vertices the size of the minimum edge cover plus the size of a maximum matching equals the number of vertices. Combining this equality with Kőnig's theorem leads to the facts that, in bipartite graphs, the size of the minimum edge cover is equal to the size of the maximum independent set, and the size of the minimum edge cover plus the size of the minimum vertex cover is equal to the number of vertices. Another class of related results concerns perfect graphs: every bipartite graph, the complement of every bipartite graph, the line graph of every bipartite graph, and the complement of the line graph of every bipartite graph, are all perfect. Perfection of bipartite graphs is easy to see (their chromatic number is two and their maximum clique size is also two) but perfection of the complements of bipartite graphs is less trivial, and is another restatement of Kőnig's theorem. This was one of the results that motivated the initial definition of perfect graphs. Perfection of the complements of line graphs of perfect graphs is yet another restatement of Kőnig's theorem, and perfection of the line graphs themselves is a restatement of an earlier theorem of Kőnig, that every bipartite graph has an edge coloring using a number of colors equal to its maximum degree. According to the strong perfect graph theorem, the perfect graphs have a forbidden graph characterization resembling that of bipartite graphs: a graph is bipartite if and only if it has no odd cycle as a subgraph, and a graph is perfect if and only if it has no odd cycle or its complement as an induced subgraph. The bipartite graphs, line graphs of bipartite graphs, and their complements form four out of the five basic classes of perfect graphs used in the proof of the strong perfect graph theorem. It follows that any subgraph of a bipartite graph is also bipartite because it cannot gain an odd cycle. For a vertex, the number of adjacent vertices is called the degree of the vertex and is denoted deg v {\displaystyle \deg v} . The degree sum formula for a bipartite graph states that The degree sequence of a bipartite graph is the pair of lists each containing the degrees of the two parts U {\displaystyle U} and V {\displaystyle V} . For example, the complete bipartite graph K3,5 has degree sequence ( 5 , 5 , 5 ) , ( 3 , 3 , 3 , 3 , 3 ) {\displaystyle (5,5,5),(3,3,3,3,3)} . Isomorphic bipartite graphs have the same degree sequence. However, the degree sequence does not, in general, uniquely identify a bipartite graph; in some cases, non-isomorphic bipartite graphs may have the same degree sequence. The bipartite realization problem is the problem of finding a simple bipartite graph with the degree sequence being two given lists of natural numbers. (Trailing zeros may be ignored since they are trivially realized by adding an appropriate number of isolated vertices to the digraph.) The biadjacency matrix of a bipartite graph ( U , V , E ) {\displaystyle (U,V,E)} is a (0,1) matrix of size | U | × | V | {\displaystyle |U|\times |V|} that has a one for each pair of adjacent vertices and a zero for nonadjacent vertices. Biadjacency matrices may be used to describe equivalences between bipartite graphs, hypergraphs, and directed graphs. A hypergraph is a combinatorial structure that, like an undirected graph, has vertices and edges, but in which the edges may be arbitrary sets of vertices rather than having to have exactly two endpoints. A bipartite graph ( U , V , E ) {\displaystyle (U,V,E)} may be used to model a hypergraph in which U is the set of vertices of the hypergraph, V is the set of hyperedges, and E contains an edge from a hypergraph vertex v to a hypergraph edge e exactly when v is one of the endpoints of e. Under this correspondence, the biadjacency matrices of bipartite graphs are exactly the incidence matrices of the corresponding hypergraphs. As a special case of this correspondence between bipartite graphs and hypergraphs, any multigraph (a graph in which there may be two or more edges between the same two vertices) may be interpreted as a hypergraph in which some hyperedges have equal sets of endpoints, and represented by a bipartite graph that does not have multiple adjacencies and in which the vertices on one side of the bipartition all have degree two. A similar reinterpretation of adjacency matrices may be used to show a one-to-one correspondence between directed graphs (on a given number of labeled vertices, allowing self-loops) and balanced bipartite graphs, with the same number of vertices on both sides of the bipartition. For, the adjacency matrix of a directed graph with n vertices can be any (0,1) matrix of size n × n {\displaystyle n\times n} , which can then be reinterpreted as the adjacency matrix of a bipartite graph with n vertices on each side of its bipartition. In this construction, the bipartite graph is the bipartite double cover of the directed graph. Algorithms It is possible to test whether a graph is bipartite, and to return either a two-coloring (if it is bipartite) or an odd cycle (if it is not) in linear time, using depth-first search (DFS). The main idea is to assign to each vertex the color that differs from the color of its parent in the DFS forest, assigning colors in a preorder traversal of the depth-first-search forest. This will necessarily provide a two-coloring of the spanning forest consisting of the edges connecting vertices to their parents, but it may not properly color some of the non-forest edges. In a DFS forest, one of the two endpoints of every non-forest edge is an ancestor of the other endpoint, and when the depth first search discovers an edge of this type it should check that these two vertices have different colors. If they do not, then the path in the forest from ancestor to descendant, together with the miscolored edge, form an odd cycle, which is returned from the algorithm together with the result that the graph is not bipartite. However, if the algorithm terminates without detecting an odd cycle of this type, then every edge must be properly colored, and the algorithm returns the coloring together with the result that the graph is bipartite. Alternatively, a similar procedure may be used with breadth-first search in place of DFS. Again, each node is given the opposite color to its parent in the search forest, in breadth-first order. If, when a vertex is colored, there exists an edge connecting it to a previously-colored vertex with the same color, then this edge together with the paths in the breadth-first search forest connecting its two endpoints to their lowest common ancestor forms an odd cycle. If the algorithm terminates without finding an odd cycle in this way, then it must have found a proper coloring, and can safely conclude that the graph is bipartite. For the intersection graphs of n {\displaystyle n} line segments or other simple shapes in the Euclidean plane, it is possible to test whether the graph is bipartite and return either a two-coloring or an odd cycle in time O ( n log n ) {\displaystyle O(n\log n)} , even though the graph itself may have up to O ( n 2 ) {\displaystyle O(n^{2})} edges. Odd cycle transversal is an NP-complete algorithmic problem that asks, given a graph G = (V,E) and a number k, whether there exists a set of k vertices whose removal from G would cause the resulting graph to be bipartite. The problem is fixed-parameter tractable, meaning that there is an algorithm whose running time can be bounded by a polynomial function of the size of the graph multiplied by a larger function of k. The name odd cycle transversal comes from the fact that a graph is bipartite if and only if it has no odd cycles. Hence, to delete vertices from a graph in order to obtain a bipartite graph, one needs to "hit all odd cycle", or find a so-called odd cycle transversal set. In the illustration, every odd cycle in the graph contains the blue (the bottommost) vertices, so removing those vertices kills all odd cycles and leaves a bipartite graph. The edge bipartization problem is the algorithmic problem of deleting as few edges as possible to make a graph bipartite and is also an important problem in graph modification algorithmics. This problem is also fixed-parameter tractable, and can be solved in time O ( 2 k m 2 ) {\textstyle O\left(2^{k}m^{2}\right)} , where k is the number of edges to delete and m is the number of edges in the input graph. A matching in a graph is a subset of its edges, no two of which share an endpoint. Polynomial time algorithms are known for many algorithmic problems on matchings, including maximum matching (finding a matching that uses as many edges as possible), maximum-weight matching, and stable marriage. In many cases, matching problems are simpler to solve on bipartite graphs than on non-bipartite graphs, and many matching algorithms such as the Hopcroft–Karp algorithm for maximum-cardinality matching work correctly only on bipartite inputs. As a simple example, suppose that a set P {\displaystyle P} of people are all seeking jobs from among a set J {\displaystyle J} of jobs, with not all people suitable for all jobs. This situation can be modeled as a bipartite graph ( P , J , E ) {\displaystyle (P,J,E)} where an edge connects each job-seeker with each suitable job. A perfect matching describes a way of simultaneously satisfying all job-seekers and filling all jobs; Hall's marriage theorem provides a characterization of the bipartite graphs which allow perfect matchings. The National Resident Matching Program applies graph matching methods to solve this problem for U.S. medical student job-seekers and hospital residency jobs. The Dulmage–Mendelsohn decomposition is a structural decomposition of bipartite graphs that is useful in finding maximum matchings. Additional applications Bipartite graphs are extensively used in modern coding theory, especially to decode codewords received from the channel. Factor graphs and Tanner graphs are examples of this. A Tanner graph is a bipartite graph in which the vertices on one side of the bipartition represent digits of a codeword, and the vertices on the other side represent combinations of digits that are expected to sum to zero in a codeword without errors. A factor graph is a closely related belief network used for probabilistic decoding of LDPC and turbo codes. In computer science, a Petri net is a mathematical modeling tool used in analysis and simulations of concurrent systems. A system is modeled as a bipartite directed graph with two sets of nodes: A set of "place" nodes that contain resources, and a set of "event" nodes which generate and/or consume resources. There are additional constraints on the nodes and edges that constrain the behavior of the system. Petri nets utilize the properties of bipartite directed graphs and other properties to allow mathematical proofs of the behavior of systems while also allowing easy implementation of simulations of the system. In projective geometry, Levi graphs are a form of bipartite graph used to model the incidences between points and lines in a configuration. Corresponding to the geometric property of points and lines that every two lines meet in at most one point and every two points be connected with a single line, Levi graphs necessarily do not contain any cycles of length four, so their girth must be six or more. See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Punched_card] | [TOKENS: 5419] |
Contents Punched card A punched card (also punch card) is a stiff paper-based medium used to store digital information via the presence or absence of holes in predefined positions. Developed over the 19th to 20th centuries, punched cards were widely used for data processing, the control of automated machines, and computing. Early applications included controlling weaving looms and recording census data. Punched cards were widely used in the 20th century, where unit record machines, organized into data processing systems, used punched cards for data input, data output, and data storage. The IBM 12-row/80-column punched card format came to dominate the industry. Many early digital computers used punched cards as the primary medium for input of both computer programs and data. Punched cards were used for decades before being replaced by magnetic tape data storage. While punched cards are now obsolete as a storage medium, as of 2012, some voting machines still used punched cards to record votes. Punched cards had a significant cultural impact in the 20th century. Their legacy persists in modern computing, influencing the 80-character line standard still present in some command-line interfaces and programming environments. History The idea of control and data storage via punched holes was developed independently on several occasions in the modern period. In most cases there is no evidence that each of the inventors was aware of any other earlier work. Basile Bouchon developed the control of a loom by punched holes in paper tape in 1725. The design was improved by his assistant Jean-Baptiste Falcon and by Jacques Vaucanson. Although these improvements controlled the patterns woven, they still required an assistant to operate the mechanism. In 1804 Joseph Marie Jacquard demonstrated a mechanism to automate loom operation. A number of punched cards were linked into a chain of any length. Each card held the instructions for shedding (raising and lowering the warp) and selecting the shuttle for a single pass. Semyon Korsakov was reputedly the first to propose punched cards in informatics for information store and search. Korsakov announced his new method and machines in September 1832. Charles Babbage proposed the use of "Number Cards", "pierced with certain holes and stand[ing] opposite levers connected with a set of figure wheels ... advanced they push in those levers opposite to which there are no holes on the cards and thus transfer that number together with its sign" in his description of the Calculating Engine's Store. There is no evidence that he built a practical example. In 1881, Jules Carpentier developed a method of recording and playing back performances on a harmonium using punched cards. The system was called the Mélographe Répétiteur and "writes down ordinary music played on the keyboard dans le langage de Jacquard", that is as holes punched in a series of cards. By 1887 Carpentier had separated the mechanism into the Melograph which recorded the player's key presses and the Melotrope which played the music. At the end of the 1800s Herman Hollerith created a method for recording data on a medium that could then be read by a machine, developing punched card data processing technology for the 1890 U.S. census. This was inspired in part by Jacquard loom weaving technology and by railway punch photographs. Punch photographs were quick ways for conductors to mark a ticket with a description of the ticket buyer (e.g., short or tall, dark or light hair). They were used to reduce ticket fraud, as conductors could "read" the punched holes to get a basic description of the person to whom the ticket was sold. Hollerith's tabulating machines read and summarized data stored on punched cards and they began use for government and commercial data processing. Initially, these electromechanical machines only counted holes, but by the 1920s they had units for carrying out basic arithmetic operations.: 124 Hollerith founded the Tabulating Machine Company (1896) which was one of four companies that were amalgamated via stock acquisition to form a fifth company, Computing-Tabulating-Recording Company (CTR) in 1911, later renamed International Business Machines Corporation (IBM) in 1924. Other companies entering the punched card business included The Tabulator Limited (Britain, 1902), Deutsche Hollerith-Maschinen Gesellschaft mbH (Dehomag) (Germany, 1911), Powers Accounting Machine Company (US, 1911), Remington Rand (US, 1927), and H.W. Egli Bull (France, 1931). These companies, and others, manufactured and marketed a variety of punched cards and unit record machines for creating, sorting, and tabulating punched cards, even after the development of electronic computers in the 1950s. Both IBM and Remington Rand tied punched card purchases to machine leases, a violation of the US 1914 Clayton Antitrust Act. In 1932, the US government took both to court on this issue. Remington Rand settled quickly. IBM viewed its business as providing a service and that the cards were part of the machine. IBM fought all the way to the Supreme Court and lost in 1936; the court ruled that IBM could only set card specifications.: 300–301 "By 1937... IBM had 32 presses at work in Endicott, N.Y., printing, cutting and stacking five to 10 million punched cards every day." Punched cards were even used as legal documents, such as U.S. Government checks and savings bonds. During World War II punched card equipment was used by the Allies in some of their efforts to decrypt Axis communications. See, for example, Central Bureau in Australia. At Bletchley Park in England, "some 2 million punched cards a week were being produced, indicating the sheer scale of this part of the operation". In Nazi Germany, punched cards were used for the censuses of various regions and other purposes (see IBM and the Holocaust). Punched card technology developed into a powerful tool for business data-processing. By 1950 punched cards had become ubiquitous in industry and government. "Do not fold, spindle or mutilate," a warning that appeared on some punched cards distributed as documents such as checks and utility bills to be returned for processing, became a motto for the post-World War II era. In 1956 IBM signed a consent decree requiring, amongst other things, that IBM would by 1962 have no more than one-half of the punched card manufacturing capacity in the United States. Tom Watson Jr.'s decision to sign this decree, where IBM saw the punched card provisions as the most significant point, completed the transfer of power to him from Thomas Watson Sr. The Univac UNITYPER introduced magnetic tape for data entry in the 1950s. During the 1960s, the punched card was gradually replaced as the primary means for data storage by magnetic tape, as better, more capable computers became available. Mohawk Data Sciences introduced a magnetic tape encoder in 1965, a system marketed as a keypunch replacement which was somewhat successful. Punched cards were still commonly used for entering both data and computer programs until the mid-1980s when the combination of lower cost magnetic disk storage, and affordable interactive terminals on less expensive minicomputers made punched cards obsolete for these roles as well.: 151 However, their influence lives on through many standard conventions and file formats. The terminals that replaced the punched cards, the IBM 3270 for example, displayed 80 columns of text in text mode, for compatibility with existing software. Some programs still operate on the convention of 80 text columns, although fewer and fewer do as newer systems employ graphical user interfaces with variable-width type fonts. Nomenclature The terms punched card, punch card, and punchcard were all commonly used, as were IBM card and Hollerith card (after Herman Hollerith). IBM used "IBM card" or, later, "punched card" at first mention in its documentation and thereafter simply "card" or "cards". Specific formats were often indicated by the number of character positions available, e.g. 80-column card. A sequence of cards that is input to or output from some step in an application's processing is called a card deck or simply deck. The rectangular, round, or oval bits of paper punched out were called chad (chads) or chips (in IBM usage). Sequential card columns allocated for a specific use, such as names, addresses, multi-digit numbers, etc., are known as a field. The first card of a group of cards, containing fixed or indicative information for that group, is known as a master card. Cards that are not master cards are detail cards. Formats The Hollerith punched cards used for the 1890 U.S. census were blank. Following that, cards commonly had printing such that the row and column position of a hole could be easily seen. Printing could include having fields named and marked by vertical lines, logos, and more. "General purpose" layouts (see, for example, the IBM 5081 below) were also available. For applications requiring master cards to be separated from following detail cards, the respective cards had different upper corner diagonal cuts and thus could be separated by a sorter. Other cards typically had one upper corner diagonal cut so that cards not oriented correctly, or cards with different corner cuts, could be identified. Herman Hollerith was awarded three patents in 1889 for electromechanical tabulating machines. These patents described both paper tape and rectangular cards as possible recording media. The card shown in U.S. patent 395,781 of January 8 was printed with a template and had hole positions arranged close to the edges so they could be reached by a railroad conductor's ticket punch, with the center reserved for written descriptions. Hollerith was originally inspired by railroad tickets that let the conductor encode a rough description of the passenger: I was traveling in the West and I had a ticket with what I think was called a punch photograph...the conductor...punched out a description of the individual, as light hair, dark eyes, large nose, etc. So you see, I only made a punch photograph of each person.: 15 When use of the ticket punch proved tiring and error-prone, Hollerith developed the pantograph "keyboard punch". It featured an enlarged diagram of the card, indicating the positions of the holes to be punched. A printed reading board could be placed under a card that was to be read manually.: 43 Hollerith envisioned a number of card sizes. In an article he wrote describing his proposed system for tabulating the 1890 U.S. census, Hollerith suggested a card 3 by 5+1⁄2 inches (7.6 by 14.0 cm) of Manila stock "would be sufficient to answer all ordinary purposes." The cards used in the 1890 census had round holes, 12 rows and 24 columns. A reading board for these cards can be seen at the Columbia University Computing History site. At some point, 3+1⁄4 by 7+3⁄8 inches (83 by 187 mm) became the standard card size. These are the dimensions of the then-current paper currency of 1862–1923. This size was needed in order to use available banking-type storage for the 60,000,000 punched cards to come nationwide. Hollerith's original system used an ad hoc coding system for each application, with groups of holes assigned specific meanings, e.g. sex or marital status. His tabulating machine had up to 40 counters, each with a dial divided into 100 divisions, with two indicator hands; one which stepped one unit with each counting pulse, the other which advanced one unit every time the other dial made a complete revolution. This arrangement allowed a count up to 9,999. During a given tabulating run counters were assigned specific holes or, using relay logic, combination of holes. Later designs led to a card with ten rows, each row assigned a digit value, 0 through 9, and 45 columns. This card provided for fields to record multi-digit numbers that tabulators could sum, instead of their simply counting cards. Hollerith's 45 column punched cards are illustrated in Comrie's The application of the Hollerith Tabulating Machine to Brown's Tables of the Moon. By the late 1920s, customers wanted to store more data on each punched card. In 1927, Thomas J. Watson Sr., IBM's head, asked two of his top inventors, Clair D. Lake and J. Royden Pierce, to independently develop ways to increase data capacity without increasing the size of the punched card. Pierce wanted to keep round holes and 45 columns but to allow each column to store more data; Lake suggested rectangular holes, which could be spaced more tightly, allowing 80 columns per punched card, thereby nearly doubling the capacity of the older format. Watson picked the latter solution, introduced as The IBM Card, in part because it was compatible with existing tabulator designs and in part because it could be protected by patents and give the company a distinct advantage, and because "competitors using mechanical sensing of holes would find it difficult to make the change". Introduced in 1928, the IBM card format had rectangular holes, 80 columns, and 10 rows. Card size is 7+3⁄8 by 3+1⁄4 inches (187 by 83 mm). The cards are made of smooth stock, 0.007 inches (180 μm) thick. There are about 143 cards to the inch (56/cm). In 1930, the IBM card format had rectangular holes, 80 columns, and 12 rows, with two more rows added to the top of the card for alphabetic coding. In 1964, IBM changed from square to round corners. They come typically in boxes of 2,000 cards or as continuous form cards. Continuous form cards could be both pre-numbered and pre-punched for document control (checks, for example). Initially designed to record responses to yes–no questions, support for numeric, alphabetic and special characters was added through the use of columns and zones. The top three positions of a column are called zone punching positions, 12 (top), 11, and 0 (0 may be either a zone punch or a digit punch). For decimal data the lower ten positions are called digit punching positions, 0 (top) through 9. An arithmetic sign can be specified for a decimal field by overpunching the field's rightmost column with a zone punch: 12 for plus, 11 for minus (CR). For Pound sterling pre-decimalization currency a penny column represents the values zero through eleven; 10 (top), 11, then 0 through 9 as above. An arithmetic sign can be punched in the adjacent shilling column.: 9 Zone punches had other uses in processing, such as indicating a master card. Diagram: Note: The 11 and 12 zones were also called the X and Y zones, respectively. In 1931, IBM began introducing upper-case letters and special characters (Powers-Samas had developed the first commercial alphabetic punched card representation in 1921).[nb 1] The 26 letters have two punches (zone [12,11,0] + digit [1–9]). The languages of Germany, Sweden, Denmark, Norway, Spain, Portugal and Finland require up to three additional letters; their punching is not shown here.: 88–90 Most special characters have two or three punches (zone [12,11,0, or none] + digit [2–7] + 8); a few special characters were exceptions: "&" is 12 only, "-" is 11 only, and "/" is 0 + 1). The Space character has no punches.: 38 The information represented in a column by a combination of zones [12, 11, 0] and digits [0–9] is dependent on the use of that column. For example, the combination "12-1" is the letter "A" in an alphabetic column, a plus signed digit "1" in a signed numeric column, or an unsigned digit "1" in a column where the "12" has some other use. The introduction of EBCDIC in 1964 defined columns with as many as six punches (zones [12,11,0,8,9] + digit [1–7]). IBM and other manufacturers used many different 80-column card character encodings. A 1969 American National Standard defined the punches for 128 characters and was named the Hollerith Punched Card Code (often referred to simply as Hollerith Card Code), honoring Hollerith.: 7 For some computer applications, binary formats were used, where each hole represented a single binary digit (or "bit"), every column (or row) is treated as a simple bit field, and every combination of holes is permitted. For example, on the IBM 701 and IBM 704, card data was read, using an IBM 711, into memory in row binary format. For each of the twelve rows of the card, 72 of the 80 columns, skipping the other eight, would be read into two 36-bit words, requiring 864 bits to store the whole card; a control panel was used to select the 72 columns to be read. Software would translate this data into the desired form. One convention was to use columns 1 through 72 for data, and columns 73 through 80 to sequentially number the cards, as shown in the picture above of a punched card for FORTRAN. Such numbered cards could be sorted by machine so that if a deck was dropped the sorting machine could be used to arrange it back in order. This convention continued to be used in FORTRAN, even in later systems where the data in all 80 columns could be read. The IBM card readers 3504, 3505 and the multifunction unit 3525 used a different encoding scheme for column binary data, also known as card image, where each column, split into two rows of 6 (12–3 and 4–9) was encoded into two 8-bit bytes, holes in each group represented by bits 2 to 7 (MSb numbering, bit 0 and 1 unused ) in successive bytes. This required 160 8-bit bytes, or 1280 bits, to store the whole card. As an aid to humans who had to deal with the punched cards, the IBM 026 and later 029 and 129 key punch machines could print human-readable text above each of the 80 columns. As a prank, punched cards could be made where every possible punch position had a hole. Such "lace cards" lacked structural strength, and would frequently buckle and jam inside the machine. The IBM 80-column punched card format dominated the industry, becoming known as just IBM cards, even though other companies made cards and equipment to process them. One of the most common punched card formats is the IBM 5081 card format, a general purpose layout with no field divisions. This format has digits printed on it corresponding to the punch positions of the digits in each of the 80 columns. Other punched card vendors manufactured cards with this same layout and number. Long cards were available with a scored stub on either end which, when torn off, left an 80 column card. The torn off card is called a stub card. 80-column cards were available scored, on either end, creating both a short card and a stub card when torn apart. Short cards can be processed by other IBM machines. A common length for stub cards was 51 columns. Stub cards were used in applications requiring tags, labels, or carbon copies. According to the IBM Archive: IBM's Supplies Division introduced the Port-A-Punch in 1958 as a fast, accurate means of manually punching holes in specially scored IBM punched cards. Designed to fit in the pocket, Port-A-Punch made it possible to create punched card documents anywhere. The product was intended for "on-the-spot" recording operations—such as physical inventories, job tickets and statistical surveys—because it eliminated the need for preliminary writing or typing of source documents. In 1969 IBM introduced a new, smaller, round-hole, 96-column card format along with the IBM System/3 low-end business computer. These cards have tiny, 1 mm diameter circular holes, smaller than those in paper tape. Data is stored in 6-bit BCD, with three rows of 32 characters each, or 8-bit EBCDIC. In this format, each column of the top tiers are combined with two punch rows from the bottom tier to form an 8-bit byte, and the middle tier is combined with two more punch rows, so that each card contains 64 bytes of 8-bit-per-byte binary coded data. As in the 80 column card, readable text was printed in the top section of the card. There was also a fourth row of 32 characters that could be printed. This format was never widely used; it was IBM-only, but they did not support it on any equipment beyond the System/3, where it was quickly superseded by the 1973 IBM 3740 Data Entry System using 8-inch floppy disks. The format was however recycled in 1978 when IBM re-used the mechanism in its IBM 3624 ATMs as print-only receipt printers. The Powers/Remington Rand card format was initially the same as Hollerith's; 45 columns and round holes. In 1930, Remington Rand leap-frogged IBM's 80 column format from 1928 by coding two characters in each of the 45 columns – producing what is now commonly called the 90-column card.: 142 There are two sets of six rows across each card. The rows in each set are labeled 0, 1/2, 3/4, 5/6, 7/8 and 9. The even numbers in a pair are formed by combining that punch with a 9 punch. Alphabetic and special characters use three or more punches. The British Powers-Samas company used a variety of card formats for their unit record equipment. They began with 45 columns and round holes. Later 36-, 40- and 65-column cards were provided. A 130-column card was also available – formed by dividing the card into two rows, each row with 65 columns and each character space with five punch positions. A 21-column card was comparable to the IBM Stub card.: 47–51 Mark sense (electrographic) cards, developed by Reynold B. Johnson at IBM, have printed ovals that could be marked with a special electrographic pencil. Cards would typically be punched with some initial information, such as the name and location of an inventory item. Information to be added, such as quantity of the item on hand, would be marked in the ovals. Card punches with an option to detect mark sense cards could then punch the corresponding information into the card. Aperture cards have a cut-out hole on the right side of the punched card. A piece of 35 mm microfilm containing a microform image is mounted in the hole. Aperture cards are used for engineering drawings from all engineering disciplines. Information about the drawing, for example the drawing number, is typically punched and printed on the remainder of the card. Manufacturing IBM's Fred M. Carroll developed a series of rotary presses that were used to produce punched cards, including a 1921 model that operated at 460 cards per minute (cpm). In 1936 he introduced a completely different press that operated at 850 cpm. Carroll's high-speed press, containing a printing cylinder, revolutionized the company's manufacturing of punched cards. It is estimated that between 1930 and 1950, the Carroll press accounted for as much as 25 percent of the company's profits. Discarded printing plates from these card presses, each printing plate the size of an IBM card and formed into a cylinder, often found use as desk pen/pencil holders, and even today are collectible IBM artifacts (every card layout had its own printing plate). In the mid-1930s a box of 1,000 cards cost $1.05 (equivalent to $25 in 2025). Cultural impact While punched cards have not been widely used for generations, the impact was so great for most of the 20th century that they still appear from time to time in popular culture. For example: metaphor... symbol of the "system"—first the registration system and then bureaucratic systems more generally ... a symbol of alienation ... Punched cards were the symbol of information machines, and so they became the symbolic point of attack. Punched cards, used for class registration, were first and foremost a symbol of uniformity. .... A student might feel "he is one of out of 27,500 IBM cards" ... The president of the Undergraduate Association criticized the University as "a machine ... IBM pattern of education."... Robert Blaumer explicated the symbolism: he referred to the "sense of impersonality... symbolized by the IBM technology."... A common example of the requests often printed on punched cards which were to be individually handled, especially those intended for the public to use and return is "Do Not Fold, Spindle or Mutilate" (in the UK "Do not bend, spike, fold or mutilate").: 43–55 Coined by Charles A. Phillips, it became a motto for the post–World War II era, and was widely mocked and satirized. Some 1960s students at Berkeley wore buttons saying: "Do not fold, spindle or mutilate. I am a student". The motto was also used for a 1970 book by Doris Miles Disney with a plot based around an early computer dating service and a 1971 made-for-TV movie based on that book, and a similarly titled 1967 Canadian short film, Do Not Fold, Staple, Spindle or Mutilate. Standards Punched card devices Processing of punched cards was handled by a variety of machines, including: See also Notes References Further reading External links |
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[SOURCE: https://github.com/solutions/industry] | [TOKENS: 345] |
Navigation Menu Search code, repositories, users, issues, pull requests... Provide feedback We read every piece of feedback, and take your input very seriously. Saved searches Use saved searches to filter your results more quickly To see all available qualifiers, see our documentation. Industry solutions Discover how GitHub’s industry solutions can help you improve efficiency, reduce costs, and capture new market opportunities. Healthcare By incorporating security checks into developer workflows, you can build secure communication channels between patients and providers. Financial Services With an AI-powered developer platform, you can build innovative financial solutions that drive economic growth. Manufacturing With robust CI/CD that can handle the complex needs of manufacturing, you can securely transform operations at scale. Government With seamless collaboration and robust compliance, GitHub helps government agencies build and innovate securely on a single, AI-powered platform. Related solutions With comprehensive security tools built into the developer workflow, you can build, secure, and ship all in one place. Scale and deliver more secure software with GitHub's unified AI-powered developer platform. Test and deploy software with simple and secure enterprise CI/CD. Get expert perspectives. Stay ahead with insights from industry leaders. 2.4x more precise leaked secrets found with fewer false positives ~25% increase in developer speed with GitHub Copilot 1min set-up time for largest repo with GitHub Codespaces +88% more productivity with GitHub Enterprise Trusted by 90% of the Fortune 100, GitHub helps millions of developers and companies collaborate, build, and deliver secure software faster. And with thousands of DevOps integrations, developers can build smarter from day one with the tools they know and love—or discover new ones. Site-wide Links Get tips, technical guides, and best practices. Twice a month. |
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[SOURCE: https://en.wikipedia.org/wiki/Information_Processing_Techniques_Office] | [TOKENS: 865] |
Contents Information Processing Techniques Office The Information Processing Techniques Office (IPTO), originally Command and Control Research, was part of the Defense Advanced Research Projects Agency of the United States Department of Defense. Origin According to an ARPA-sponsored history of the organization, IPTO grew from a distinctly unpromising beginning: the Air Force had a large, expensive computer (AN/FSQ 321A) which was intended as a backup for the SAGE air defense program, but no longer needed; and it also had too few required tasks to maintain the desired staffing level at its main software contractor, the System Development Corporation (SDC). Accordingly, the Under Secretary of Defense for Research and Engineering decided to capitalize on these "sunk costs" and SDC expertise by standing up an ARPA program in Command & Control Research. It was accordingly begun in June 1961 with an initial budget of $5.8 million, to include shipping, installation, and checking out the computer at SDC facilities. This new ARPA program was envisioned to "support research on the conceptual aspects of command and control." Most fortunately, ARPA then hired J.C.R. Licklider away from Bolt, Beranek and Newman to be IPTO's first director. Licklider started work in October 1962, and until his term ended in 1964, he "...initiated three of the most important developments in information technology: the creation of computer science departments at several major universities, time-sharing, and networking". By the late 1960s, his promotion of the concept had inspired a primitive version of his vision called ARPANET, which expanded into a network of networks in the 1970s that became the Internet. Licklider described how he had re-envisioned command and control research as research into interactive computing as follows: There was a belief in the heads of a number of people -- a small number -- that people could really become very much more effective in their thinking and decision-making, if they had the support of a computer system, good displays and so forth, good data bases, computation at your command. It was kind of an image that we were working toward the realization of.... It really wasn't a command and control research program. It was an interactive computing program. And my belief was, and still is, you can't really do command and control outside the framework of such a thing... of course, that wasn't believed by people in the command control field. Licklider quickly set about detaching the program from its sole reliance on a surplus Air Force computer and single industrial contractor. As he recalled: Essentially what I did on the command and control thing was to try to figure out where the best academic computer centers were, and then go systematically about trying to get research contracts set up with them, aiming for three or four major ones and then a lot of little ones. Under Licklider's direction, the stated mission of IPTO was: [To] create a new generation of computational and information systems that possess capabilities far beyond those of current systems. These cognitive systems - systems that know what they're doing: Later history Ivan Sutherland replaced J. C. R. Licklider as IPTO's director when Licklider left ARPA in 1964. Sutherland was 26 years old at the time. Bob Taylor was hired as Sutherland's assistant in 1965 and became director in 1966. During Taylor's tenure, the IPTO facility consisted of a spacious office for the director in Ring D of The Pentagon and a small "terminal room" with remote terminals to mainframe computers at MIT, the University of California, Berkeley and the AN/FSQ-32 in Santa Monica. The staff at the Pentagon consisted of the director and his secretary. The budget was $19 million which funded computer research projects at MIT and other institutions in Massachusetts and California. In 1966 Taylor went to ARPA, on Ring E, for funding to create a computer network that used interactive computing. He got $1 million and hired Lawrence Roberts to manage the project. IPTO was combined with the Transformational Convergence Technology Office (TCTO) to form the Information Innovation Office (I2O) in 2010. References External links |
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Contents Close Encounters of the Third Kind Close Encounters of the Third Kind is a 1977 American science fiction drama film written and directed by Steven Spielberg, starring Richard Dreyfuss, Melinda Dillon, Teri Garr, Bob Balaban, Cary Guffey, and François Truffaut. The film depicts the story of Roy Neary, an everyday blue-collar worker in Indiana, whose life changes after an encounter with an unidentified flying object (UFO), and Jillian Guiler, a single mother whose three-year-old son Barry is abducted during the same UFO manifestation. Close Encounters was a long-cherished project for Spielberg. In late 1973, he developed a deal with Columbia Pictures for a science-fiction film. Though Spielberg received sole credit for the script, he was assisted by Paul Schrader, John Hill, David Giler, Hal Barwood, Matthew Robbins, and Jerry Belson, all of whom contributed to the screenplay in varying degrees[citation needed]. The title is derived from astronomer and Ufologist J. Allen Hynek's classification of close encounters with extraterrestrials, in which the third kind denotes human observations of extraterrestrials or "animate beings". Douglas Trumbull served as the visual effects supervisor, while Carlo Rambaldi designed the aliens. Made on a production budget of US$19.4 million, Close Encounters was released in a limited number of cities on November 16 and 23, 1977, and expanded into wide release the following month. It was a critical and financial success, eventually grossing over $300 million worldwide and becoming the third highest-grossing film of 1977 behind only Star Wars and Smokey and the Bandit. It received numerous awards and nominations at the 50th Academy Awards, 32nd British Academy Film Awards, the 35th Golden Globe Awards and the 5th Saturn Awards, and has been widely acclaimed by the American Film Institute. In December 2007, it was deemed "culturally, historically, or aesthetically significant" by the United States Library of Congress and selected for preservation in the National Film Registry. A Special Edition was released theatrically in 1980. Spielberg agreed to create this edition to add more scenes that they had been unable to include in the original release, with the studio demanding a controversial scene depicting the interior of the extraterrestrial mothership. Spielberg's dissatisfaction with the altered ending scene led to a third version, the Director's Cut on VHS and LaserDisc in 1998 (and later DVD and Blu-ray). It is the longest version, combining Spielberg's favorite elements from both previous editions but removing the scenes inside the mothership. The film was later remastered in 4K and was then re-released in theaters on September 1, 2017, by Sony Pictures Releasing for its 40th anniversary. Plot In 1977, French scientist Claude Lacombe, along with interpreter and cartographer David Laughlin, examine Flight 19—a group of United States Navy aircraft that vanished over the Bermuda Triangle in 1945—now found immaculate and abandoned in the Sonoran Desert. They later learn that the SS Cotopaxi has similarly been found abandoned in the middle of the Gobi Desert. Meanwhile, near Indianapolis, two airplanes narrowly avoid a mid-air collision with an unidentified flying object (UFO). At a rural home outside Muncie, Indiana, three-year-old Barry Guiler wakes to find his toys operating on their own and the fridge ransacked. He follows a trail outside before his mother, Jillian, catches him. Widespread power outages occur throughout the area, forcing electric utility lineman Roy Neary to investigate. En route, Roy experiences a close encounter with a UFO, and when it flies over his truck, it lightly burns the side of his face with its lights. The UFO takes off with three others in the sky, as Roy and police officers unsuccessfully pursue them by road. Roy becomes fascinated with the UFOs and obsessed with a subliminal image of a mountainous shape, repeatedly making models of it. His increasingly erratic and eccentric behavior worries his wife Ronnie and their three children, and his friends and neighbors ostracize him. Ronnie eventually leaves with the children after Roy brings dirt, bricks, and other debris into their home to sculpt a large scale replica of the mountain. Jillian also begins compulsively sketching the same mountain. Soon after, she is terrorized in her home by a UFO which descends from the clouds. She fights off aggressive attempts by unseen beings to enter the home, but in the chaos, Barry is abducted. Lacombe, Laughlin, and a group of United Nations experts continue to investigate increasing UFO activity and strange, related occurrences. Witnesses in Dharamsala, Northern India report that the UFOs make distinctive sounds: a five-tone musical phrase. Scientists broadcast the phrase to outer space, but receive only a seemingly meaningless repeating series of numbers in response. Laughlin eventually recognizes it as a set of geographical coordinates, which point to Devils Tower near Moorcroft, Wyoming. The US Army evacuates the area around Devils Tower, planting false reports in the media that a train wreck has spilled a toxic nerve gas, while actually preparing a secret landing site for the UFOs. Seeing the mountain on the news, Roy and Jillian recognize it as the one they have been visualizing. Despite the evacuation order, they, along with others who have been experiencing the visions, set out for Devils Tower, but are intercepted by the Army. Lacombe interviews Roy, who is unable to explain his compulsion to reach the mountain beyond seeking answers. While the others are escorted away, Roy and Jillian escape and eventually reach the mountain site just as UFOs appear in the night sky. The specialists there begin to communicate with the UFOs—which gradually appear by the dozens—by using light and sound on a large electrical billboard. An enormous mothership eventually arrives and seemingly conveys to the researchers a tonal means of communication before landing. A hatch opens, from which various humans and animals are released, having not aged since they were taken, including World War II pilots, Cotopaxi sailors, and Barry, who reunites with Jillian. Seeing Roy, Lacombe suggests preparing him for inclusion in the government's select group of potential visitors to the mothership. The extraterrestrials finally emerge from the mothership and select Roy to join their travels. As Roy enters the mothership, one of the extraterrestrials pauses for a few moments with the humans. Lacombe uses Curwen hand signs that correspond to the five-note tonal phrase. The extraterrestrial responds in kind, smiles, and returns to its ship, which takes to the sky. Cast Production The film's inspiration arose in director Steven Spielberg's childhood, when he and his father watched a meteor shower in New Jersey. At age 18, Spielberg completed the full-length science fiction film Firelight. Many scenes from Firelight were incorporated in Close Encounters on a shot-for-shot basis. In 1970, he wrote the short story "Experiences" about a lovers' lane in a Midwestern farming community and the "light show" a group of teenagers see in the night sky. In late 1973, after completing work on The Sugarland Express, Spielberg developed a deal with Columbia Pictures for a science-fiction film. 20th Century Fox had previously turned down the offer. Julia and Michael Phillips signed on as producers. Spielberg first considered doing a documentary or low-budget feature film about people who believed in UFOs. He decided "a film that depended on state-of-the-art technology couldn't be made for $2.5 million." Borrowing a phrase from the ending of The Thing from Another World, he retitled the film Watch the Skies, rewriting the premise concerning Project Blue Book and pitching the concept to Willard Huyck and Gloria Katz. Katz remembered, "It had flying saucers from outer space landing on Robertson Boulevard [in West Hollywood, California]. I go, 'Steve, that's the worst idea I ever heard.'" Spielberg brought Paul Schrader to write the script in December 1973 with principal photography to begin in late 1974. To discuss the script, Spielberg visited the home where Schrader lived with his brother Leonard. However, Spielberg started work on Jaws in 1974, delaying Watch the Skies. With the financial and critical success of Jaws, Spielberg was able to negotiate a high degree of creative control from Columbia, including the right to make the film any way he wanted. Schrader submitted his script, which Spielberg called "one of the most embarrassing screenplays ever professionally turned in to a major film studio or director" and "a terribly guilt-ridden story not about UFOs at all". Titled Kingdom Come, the script's protagonist was a 45-year-old Air Force officer named Paul Van Owen who worked with Project Blue Book. "[His] job for the government is to ridicule and debunk flying saucers." Schrader continued: "One day he has an encounter. He goes to the government, threatening to blow the lid off to the public. Instead, he and the government spend 15 years trying to make contact." Spielberg and Schrader experienced creative differences, hiring John Hill to rewrite. At one point, the main character was a police officer. Spielberg "[found] it hard to identify with men in uniform. I wanted to have Mr. Everyday Regular Fella." Spielberg rejected the Schrader/Hill script during post-production on Jaws, reflecting that "they wanted to make it like a James Bond adventure". David Giler performed a rewrite; Hal Barwood and Matthew Robbins, friends of Spielberg, suggested the plot device of a kidnapped child. Spielberg then began to write the script. The song "When You Wish upon a Star" from Pinocchio influenced Spielberg's writing style. "I hung my story on the mood the song created, the way it affected me personally." During pre-production, the title was changed from Kingdom Come to Close Encounters of the Third Kind. J. Allen Hynek, who worked with the United States Air Force on Project Blue Book, was hired as a scientific consultant. Hynek said that "even though the film is fiction, it's based for the most part on the known facts of the UFO mystery, and it certainly catches the flavor of the phenomenon. Spielberg was under enormous pressure to make another blockbuster after Jaws, but he decided to make a UFO film. He put his career on the line." USAF and NASA declined to cooperate on the film. NASA reportedly sent a twenty-page letter to Spielberg, telling him that releasing the film was dangerous. In an interview, he said: "I really found my faith when I heard that the Government was opposed to the film. If NASA took the time to write me a 20-page letter, then I knew there must be something happening." Early in pre-production, Spielberg hired film title designer Dan Perri to design a logotype. Perri, who had previously worked on The Exorcist (1973) and Taxi Driver (1976), produced a logotype in Handel Gothic typeface, with only a script to work from. Delighted with the result, Spielberg applied the logo to all production stationery and crew shirts. Unusual in filmmaking, Spielberg carried enough influence to maintain creative control over the film's entire branding and asked Perri to design the advertising campaign and title sequence based on his logo. Perri later designed titles for many other major Hollywood pictures, including Star Wars (1977), Raging Bull (1980), and Airplane! (1980). Principal photography began on May 16, 1976, though an Associated Press report in August 1975 had suggested filming would start in late 1975. Spielberg did not want to do any location shooting because of his negative experience on Jaws and wanted to shoot Close Encounters entirely on sound stages, but eventually dropped the idea. Filming took place in Burbank, California; Devils Tower National Monument in Wyoming; two abandoned World War II airship hangars at the former Brookley Air Force Base in Mobile, Alabama; and the Louisville and Nashville Railroad depot in Bay Minette, Alabama. The home where Barry is abducted is located outside the town of Fairhope, Alabama. Roy Neary's home is on Carlisle Drive East in Mobile. The UFOs fly through the former toll booth at the Vincent Thomas Bridge, San Pedro, California. The Sonora Desert sequence was photographed at the Dumont Dunes, California, and the Dharmsala-India exteriors were filmed at the small village of Hal near Khalapur, 35 kilometres (22 mi) outside Mumbai, India. The hangars in Alabama were six times larger than the biggest sound stage in the world. Various technical and budgetary problems occurred during filming. Spielberg called the production of Close Encounters "twice as bad and twice as expensive [as Jaws]". Matters worsened when Columbia Pictures experienced financial difficulties. In his original 1973 pitch to Columbia, Spielberg claimed production would cost $2.7 million, although he revealed to producer Julia Phillips that he knew the budget would have to be much higher; the final budget came to $19.4 million. Columbia studio executive John Veich remembered, "If we knew it was going to cost that much, we wouldn't have greenlighted it because we didn't have the money." Spielberg hired Joe Alves, his collaborator on Jaws, as production designer. In addition, the 1976 Atlantic hurricane season brought tropical storms to Alabama. A large portion of the sound stage in Alabama was damaged because of a lightning strike. Columbia raised $7 million from three sources: Time Inc., EMI, and German tax shelters. Cinematographer Vilmos Zsigmond said that, during shooting, Spielberg got more ideas by watching films every night, which in turn extended the production schedule because he was continually adding new scenes. Zsigmond previously turned down the chance to work on Jaws. In her 1991 book You'll Never Eat Lunch in This Town Again, producer Julia Phillips wrote highly profane remarks about Spielberg, Zsigmond, and Truffaut, because she was fired during post-production due to a cocaine addiction. Phillips blamed it on Spielberg being a perfectionist. Douglas Trumbull was the visual effects supervisor, and Carlo Rambaldi designed the extraterrestrials. Trumbull joked that the visual effects budget of $3.3 million could have been used to produce an additional film. His work helped lead to advances in motion control photography. The mothership was designed by Ralph McQuarrie and built by Greg Jein. The look of the ship was inspired by an oil refinery Spielberg saw at night in India. Instead of the metallic hardware look of Star Wars, the emphasis was on luminescence of the UFOs. One of the UFO models was an oxygen mask with lights attached to it, used because of its irregular shape. As a subtle in-joke, Dennis Muren (who had just finished working on Star Wars) put a small R2-D2 model onto the underside of the mothership and a pea-sized TIE fighter to the end of one of the structures extending from the mothership. Model makers also included a mailbox, great-white shark, Volkswagen bus, and a small graveyard. The model also included alien figures moving in the windows of the miniature, though were not very visible in the final film. The mothership model is on permanent display steps away from the space shuttle orbiter Discovery in the Smithsonian Institution's Air and Space Museum Udvar-Hazy Annex at Washington Dulles Airport in Chantilly, Virginia. Close Encounters was filmed anamorphically and the visual effects sequences were shot on 70 mm film, which has greater resolution than the 35 mm film used for the rest of the production, so that when the miniature effects were combined with full-sized elements through an optical printer, the effects footage would still appear clear and sharp though having lost one generation's worth of visual fidelity. A test reel using computer-generated imagery was created for the UFOs, but Spielberg found it would be too expensive and ineffective because CGI was in its infancy in the mid-1970s. The small extraterrestrials in the final scenes were played by fifty local six-year-old girls in Mobile, Alabama. That decision was requested by Spielberg because "girls move more gracefully than boys". Puppetry was attempted for the extraterrestrials, but the idea failed. However, Rambaldi successfully used puppetry to depict two of the extraterrestrials, starting with a marionette (for the tall extraterrestrial that is the first emerging from the mothership in what was originally a test shot) and an articulated puppet for the extraterrestrial that communicates via hand signals near the end of the film. Close Encounters is the first collaboration between film editor Michael Kahn and Spielberg. Their working relationship has continued for the rest of Spielberg's films. Spielberg said that no film he has ever made since has been as hard to edit as the last 25 minutes of Close Encounters and that he and Kahn went through thousands of feet of film to find the right shots for the end sequence. When Kahn and Spielberg completed the first cut of the film, Spielberg was dissatisfied because "there wasn't enough wow-ness". Pick-ups were commissioned but cinematographer Vilmos Zsigmond could not participate due to other commitments. John A. Alonzo, László Kovács, and Douglas Slocombe worked on the pick-ups. Lacombe was originally intended to find Flight 19 hidden in the Amazon rainforest, but the idea was changed to the Sonoran Desert. Spielberg also took 7.5 minutes out from the preview. Music The film score was composed, conducted, and produced by John Williams, who had previously worked on Spielberg's Jaws, and performed by the Hollywood Studio Symphony. Williams included the ominous two note phrase of the Jaws theme delivered by the mothership. Williams wrote more than 300 examples of the iconic five-tone motif, to be used by scientists to communicate with the visiting spaceship as a mathematical language, before Spielberg chose the one incorporated into the film's signature theme. Williams decided on five notes because "it has to be somewhere between a fragment ... which is four notes, and a song ... which is seven notes, so he decided, mathematically, it would be five notes." Spielberg called Williams's work "'When You Wish Upon a Star' meets science fiction". Incidentally, Williams briefly included the signature melody into the score at Spielberg's behest, just before Roy Neary turns to board the mothership. The synthesizer playing the five notes is an ARP 2500. Vice President of Engineering at ARP Instruments, Phillip Dodds, was sent to install the unit on the film set and was subsequently cast as Jean Claude, the musician who plays the sequence on the huge synthesizer in an attempt to communicate with the extraterrestrial mothership. Spielberg initially included Cliff Edwards's original "When You Wish upon a Star" from Pinocchio in the closing credits, but after a Dallas preview where several members of the audience audibly snickered at the inclusion, the song was dropped and replaced with Williams's orchestral version. Phrases from "When You Wish Upon a Star" are included in the final sequence in the director's cut and in the special edition of the end titles on the 1998 Collector's Edition of the soundtrack. The score was recorded at Warner Bros. Studios in Burbank, California. Williams was nominated for two Academy Awards in 1978, one for his score to Star Wars and one for his score to Close Encounters. He won for Star Wars, though he later won two Grammy Awards in 1979 for his Close Encounters score (one for Best Original Film Score and one for Best Instrumental Composition for "Theme from Close Encounters"). Themes Film critic Charlene Engel observed: Close Encounters suggests that humankind has reached the point where it is ready to enter the community of the cosmos. While it is a computer which makes the final musical conversation with the extraterrestrial guests possible, the characteristics bringing Neary to make his way to Devils Tower have little to do with technical expertise or computer literacy. These are virtues taught in schools that will be evolved in the 21st century. The film also evokes typical science fiction archetypes and motifs. The film portrays new technologies as a natural and expected outcome of human development and indication of health and growth. Other critics found a variety of Judeo-Christian analogies. Devils Tower parallels Mount Sinai, the extraterrestrials as God, and Roy Neary as Moses. Cecil B. DeMille's The Ten Commandments is on television at the Neary household. Some found close relations between Elijah and Roy; Elijah was taken into a "chariot of fire", akin to Roy boarding the UFO. Climbing Devils Tower behind the faltering Jillian, Roy exhorts Jillian to keep moving and not to look back, a contrast to Lot's wife, who looked back at Sodom and turned into a pillar of salt. Spielberg explained, "I wanted to make Close Encounters a very accessible story about the everyday individual who has a sighting that overturns his life, and throws it into complete upheaval as he starts to become more and more obsessed with this experience." Roy's wife Ronnie attempts to hide the sunburn caused by Roy's exposure to the UFOs and wants him to forget his encounter with them. She is embarrassed and bewildered by what has happened to him and desperately wants her ordinary life back. The expression of his lost life is seen when he is sculpting a huge model of Devils Tower in his living room, with his family deserting him. Roy's obsession with an idea implanted by an extraterrestrial intelligence, his construction of the model, and his gradual loss of contact with his wife, mimic the events in the short story "Dulcie and Decorum" (1955) by Damon Knight.[citation needed] Close Encounters studies the form of "youth spiritual yearning". Barry Guiler, the unfearing child who refers to the UFOs and their paraphernalia as "toys" (although that was unscripted, with the child being drawn to smile by being shown toys offstage), serves as a motif for childlike innocence and openness in the face of the unknown. Spielberg also compared the theme of communication as highlighting that of tolerance: "If we can talk to extraterrestrials in Close Encounters of the Third Kind, why not with the Reds in the Cold War?" Sleeping is the final obstacle to overcome in the ascent of Devils Tower. Roy, Jillian, and a third invitee, Larry Butler, climb the mountain pursued by government helicopters spraying sleeping gas. Larry stops to rest, is gassed, and falls into a deep sleep. In his interview with Spielberg on Inside the Actors Studio, James Lipton suggested Close Encounters has another, more personal theme for Spielberg: "Your father was a computer engineer; your mother was a concert pianist, and when the spaceship lands, they make music together on the computer", suggesting that Roy Neary's boarding the spaceship represents Spielberg's wish to be reunited with his parents. The director had not consciously intended this aspect. In a 2005 interview, Spielberg stated that he made Close Encounters when he did not have children, and if he were making it today, he would never have had Roy leave his family and board the mothership. Communication and language issues constitute additional themes as noted by Andrew Johnston in Time Out New York: "Throughout the film, there are many scenes that anticipate themes Spielberg would explore in subsequent projects, but his execution of these ideas here is usually more interesting and subtle. In Amistad, for example, he devotes much time to illustrating the language barrier separating Africans from both their captors and their potential saviors. It's an essential plot point, but it's so belabored that the story gets bogged down. In CE3K, the language problem is illustrated concisely by a quick scene in which an interpreter translates Spanish into English for Laughlin so he can turn around and translate it into French for Lacombe. Since Spielberg doesn't ram the language problem down our throats, the extraterrestrials' solution—using music to communicate with humanity—seems more elegant and natural." Release and reception The film was to be released in mid-1977 but was delayed to November because of the various production problems. Close Encounters premiered at the Ziegfeld Theatre in New York City on November 16, 1977, and continued there and at the Cinerama Dome in Los Angeles, grossing $1,077,000. Its national release was December 14, in 270 theaters and grossing $10,115,000 in one week with a per-screen average of $37,460. On December 21, 301 more theaters were added. By the end of the second week of national release it had grossed $24,695,317. It made a record $3,026,558 on December 26, 1977, and set a one-week record of $17,393,654 from December 26 to January 1. The film opened internationally on February 24, 1978, and grossed $27 million by the end of March from 19 countries. Close Encounters received mostly positive reviews and became a certified box office success, grossing $116.39 million in the United States and Canada, and $171.7 million in foreign countries, for $288 million worldwide. It was the most successful Columbia Pictures film at that time. Released in conjunction with Close Encounters of the Third Kind was a novelization of the film, credited solely to Steven Spielberg but largely ghostwritten by Leslie Waller. Spielberg later explained to Starlog magazine, It was very early on when we made the deal with [the publishers] Dell... It included an advance with a promise that I was going to have direct writing input into the book. But post-production on the movie became so impossible that I had to get somebody else to write it. I didn't write the first, second, or third drafts. Those were written, based on my screenplay, by Leslie Waller, a very good writer. When I read his drafts, though, I told the publishers that unless it was cleaned up I wouldn't let my name go out with the book. So I sat down and spent less than a week – I wouldn't say rewriting the novel – but polishing it, and taking a lot of the plot and twisting it back into the direction of the screenplay. All told, there's about 20 percent of me in the book. I wish I could say there was more, but there's not. I cringe when I see my name on the cover, and I usually avoid it at bookstores. Actually, I've never bought a copy. Jonathan Rosenbaum refers to the film as "the best expression of Spielberg's benign, dreamy-eyed vision". A.D. Murphy of Variety magazine gave a positive review but wrote that Close Encounters "lacks the warmth and humanity" of George Lucas's Star Wars. Murphy found most of the film slow-paced, but praised the climax. On Sneak Previews, Gene Siskel and Roger Ebert highly recommended the film. Siskel praised the message of not being "afraid of the unknown", said Dreyfuss was "perfectly cast", and described the ending as "a wonderful scene, combining fantasy, adventure and mystery". However, he mentioned that the story got "bogged down" by a subplot in the middle. Ebert said "the last 30 minutes are among the most marvelous things I've ever seen on the screen" and that the film was "like a kid's picture...in its innocence". Pauline Kael similarly called it "a kid's film in the best sense". Kael wrote that, "Spielberg is the son of an electrical-engineer, sci-fi-addict father and a classical-pianist mother, and in the climax of the film he does justice to both. Under the French scientist’s direction, the earthlings are ready with a console, and they greet the great craft with an oboe solo variation on the five-note theme; the craft answers in deep, tuba tones. The dialogue becomes blissfully garrulous. And with light flooding out from the windows of this omniscient airship—it’s like New York’s skyscrapers all lighted up on a summer night—there is a conversational duet: the music of the spheres. This is one of the peerless moments in movie history—spiritually reassuring, magical, and funny at the same time. Very few movies have ever hit upon this combination of fantasy and amusement—The Wizard of Oz, perhaps, in a plainer, down-home way." The review aggregator website Rotten Tomatoes reports that 91% out of 116 reviews were positive, with the website's consensus reading: "Close Encounters of the Third Kind is deeply humane sci-fi exploring male obsession, cosmic mysticism, and music." On Metacritic, the film has a weighted average score of 90 out of 100, indicating "universal acclaim". Jean Renoir compared Spielberg's storytelling to Jules Verne and Georges Méliès. Ray Bradbury declared it the greatest science fiction film ever made. David Thomson wrote that "Close Encounters had a flawless wonder, such that it might be the first film ever made" calling it "a tribute to the richness of human imagination" and "as close to a mystical experience as a major film has come, but it's the mysticism of common sense... The movie could have been naive and sentimental—it was inspired by Disney—but Spielberg never relinquishes his practicality and his eye for everyday detail." On the final cut privilege, Spielberg was dissatisfied with the film. Columbia Pictures was experiencing financial problems, and depending on this film to save their company. He explained, "I wanted to have another six months to finish off this film, and release it in summer 1978. They told me they needed this film out immediately. Anyway, Close Encounters was a huge financial success and I told them I wanted to make my own director's cut. They agreed on the condition that I show the inside of the mothership so they could have something to hang a [reissue marketing] campaign on. I never should have shown the inside of the mothership." In 1979, Columbia gave Spielberg $1.5 million to produce what became the Special Edition. Spielberg added seven minutes of new and previously discarded footage, but also deleted or shortened various existing scenes by ten minutes, so that its 132-minute runtime is 3 minutes shorter than the original release. The Special Edition features several new character development scenes, the discovery of the SS Cotopaxi in the Gobi Desert, and a view of the inside of the mothership. Close Encounters of the Third Kind: The Special Edition was released on August 3, 1980, making a further $15.7 million, accumulating a final $303.7 million box office gross. Roger Ebert "thought the original film was an astonishing achievement, capturing the feeling of awe and wonder we have when considering the likelihood of life beyond the Earth. ... This new version ... is, quite simply, a better film ... Why didn't Spielberg make it this good the first time?" The 1980 Special Edition was the only version officially available for many years on VHS. It was RCA/Columbia Pictures Home Video's biggest selling title with sales of 60,000 in its first three years of release in the United States. Then, in 1990, The Criterion Collection offered two versions for LaserDisc, one a variant of the original 1977 edition (with subtle edits made by Spielberg which became the syndicated television version), the other the Special Edition (programmed by the viewer using the LaserDisc player's remote features that predate the seamless branching of DVDs). This triple-disc LaserDisc set also includes an interactive Making Close Encounters documentary featuring interviews with Spielberg and other cast and crew involved with the film, and stills and script excerpts. In 1993, the Special Edition was released on VHS and LaserDisc with no further release for 14 years. Vincent Misiano reviewed Close Encounters: The Special Edition in Ares Magazine #5 and commented that "Artists in other media have always had the luxury of returning to a piece, reworking and refining it. For various reasons, money first among them, this opportunity has rarely been afforded to filmmakers. Steven Spielberg has been given the chance and used it well." On May 12, 1998, Spielberg recut Close Encounters again for the Director's Cut, released as simply the "Collector's Edition" on VHS. This version is a re-edit of the original 1977 release with some elements of the 1980 Special Edition, but omits the mothership interior scenes as Spielberg said they should have remained a mystery. The director's cut is the longest release of the film at 137 minutes, two minutes longer than the theatrical version and five minutes longer than the Special Edition. A LaserDisc release of the Collector's Edition, on July 14, 1998, includes a new 101-minute documentary, The Making of Close Encounters, which was produced in 1997 and features interviews with Spielberg, the main cast, and notable crew members. Many other alternative versions were made for network and syndicated television, and the Criterion LaserDisc version. Some of these combined all released material from the 1977 and 1980 versions. However, most of these versions were not edited by Spielberg, who regards the Collector's Edition as his definitive version. The Collector's Edition was given a limited release as part of a roadshow featuring select films to celebrate Columbia Pictures's 75th anniversary in 1999. It was the first time this version of the film had been shown theatrically. This was once again released in theaters on September 1, 2017, in tribute to the film's 40th anniversary. It made $1.8 million in the weekend ($2.3 million over the four-day Labor Day holiday), pushing its career global gross to over $306 million worldwide. Close Encounters was released on DVD on May 29, 2001, in a two-disc Collector's Edition set that contains only the director's cut. This set contains several extra features, including the 1997 documentary, a featurette from 1977, trailers, and deleted scenes that includes the mothership interior from the 1980 Special Edition. A single-disc DVD edition was released on August 27, 2002. In tribute to the film's 30th anniversary, Sony Pictures released it on DVD and Blu-ray in 2007. For the first time, all three versions were packaged together. Then in 2017, in honor of its 40th anniversary, the film was given a 4K restoration of the original camera negative. Following its theatrical re-release of the director's cut, the film was released in 4K and Blu-ray with all three versions given the same 4K treatment. Legacy Observers credited the Close Encounters for launching the reemergence of a large market for science fiction films in the 1980s alongside Star Wars (1977) and Superman (1978). In 1985, Spielberg donated $100,000 to the Planetary Society for Megachannel ExtraTerrestrial Assay. Shortly after the film's release in late 1977, Spielberg considered either a sequel or prequel, but decided against it. He explained, "The army's knowledge and ensuing cover-up is so subterranean that it would take a creative screen story, perhaps someone else making the picture and giving it the equal time it deserves." When asked in 1980 to select a single "master image" that summed up his film career, Spielberg chose the shot of Barry opening his living room door to see the blazing orange light from the UFO. "That was beautiful but awful light, just like fire coming through the doorway. [Barry's] very small, and it's a very large door, and there's a lot of promise or danger outside that door." In 2007, Close Encounters was deemed "culturally, historically, or aesthetically significant" by the United States Library of Congress and was added to the National Film Registry for preservation. In American Film Institute polls, Close Encounters has been voted the 64th-greatest American film, the 31st-most thrilling, and the 58th-most inspiring. It was also nominated for the top 10 science fiction films in AFI's 10 Top 10 and the tenth-anniversary edition of the 100 Movies list. The score by John Williams was nominated for AFI's 100 Years of Film Scores. In 2011, ABC aired a primetime special, Best in Film: The Greatest Movies of Our Time, that counted down the best films chosen by fans based on results of a poll conducted by ABC and People magazine. Close Encounters of the Third Kind was selected as the #5 Best Sci-Fi Film. The Guardian also selected the film as the 11th best Sci-Fi and fantasy film of all time. In 2024, Close Encounters of the Third Kind was included in Rolling Stone's "The 150 Best Science Fiction Movies of All Time" list at #3. Many prominent directors have cited Close Encounters as one of their favorites, among them Stanley Kubrick, Edgar Wright, Bong Joon-ho, Spike Lee, Denis Villeneuve, Guillermo del Toro, Christopher Nolan, Greta Gerwig, Andrew Stanton, Patrick Read Johnson and Michael Williams. Stephen King named it one of his ten favorite movies. See also Notes References Further reading External links |
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[SOURCE: https://github.com/solutions] | [TOKENS: 365] |
Navigation Menu Search code, repositories, users, issues, pull requests... Provide feedback We read every piece of feedback, and take your input very seriously. Saved searches Use saved searches to filter your results more quickly To see all available qualifiers, see our documentation. AI-powered platform solutions to solve your company’s challenges GitHub empowers your team to deliver software faster and more efficiently, while maintaining robust security and compliance. GitHub scales withteams of any size Build, scale, and deliver secure software faster with GitHub’s AI-powered developer platform. With CI/CD, Dependabot, and the world's largest developer community, GitHub provides everything your team needs to ship secure software faster. Go from idea to IPO in one place, complete with personalized onboarding, office hours, and tailored product guidance. Solving industry-specificchallenges By incorporating security checks into developer workflows, you can build secure communication channels between patients and providers. With an AI-powered developer platform, you can build innovative financial solutions that drive economic growth. With robust CI/CD that can handle the complex needs of manufacturing, you can securely transform operations at scale. The solutions you needto build what you want Assess, upgrade, and migrate apps to the cloud with GitHub Copilot. With comprehensive security tools built into the developer workflow, you can build, secure, and ship all in one place. Scale and deliver more secure software with GitHub's unified AI-powered developer platform. Adopted by the world's leading organizations Trusted by 90% of the Fortune 100, GitHub helps millions of developers and companies collaborate, build, and deliver secure software faster. And with thousands of DevOps integrations, developers can build smarter from day one with the tools they know and love—or discover new ones. Site-wide Links Get tips, technical guides, and best practices. Twice a month. |
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[SOURCE: https://en.wikipedia.org/wiki/FAUST_(programming_language)] | [TOKENS: 1008] |
Contents FAUST (programming language) FAUST (Functional AUdio STream) is a domain-specific purely functional, text-based visual programming language for implementing signal processing algorithms in the form of libraries, audio plug-ins, or standalone applications. A FAUST program denotes a signal processor: a mathematical function that is applied to some input signal and then fed out. It is free and open-source software released with a GNU General Public License (GPL). Overview The FAUST programming model combines a functional programming approach with a block diagram syntax: The FAUST compiler translates FAUST code into a C++ object, which may then interface with other C++ code to produce a full program. It can also cross compile (translate) the FAUST digital signal processing (DSP) specification to: C, C++, C#, Cmajor, Codebox (Max), D, interpreter, Java, JSFX (REAPER), LLVM IR, Julia, Rust, and WebAssembly (Wast/Wasm). The generated code works at the sample level. It is therefore suited to implement low-level DSP functions like recursive filters. The code may also be embedded. It is self-contained and does not depend on any DSP library or runtime system. It has a very deterministic behavior and a constant memory size. The semantics of FAUST is driven to be simple and well-defined. It allows the FAUST compiler to be semantically driven. Instead of compiling a program literally, it compiles the mathematical function it denotes. This can promote component reuse. Moreover, having access to the exact semantics of a FAUST program can simplify preservation issues. FAUST is a textual language but block diagram oriented. It combines two approaches: functional programming and algebraic block diagrams, which are constructed via function composition. For that, FAUST relies on a block diagram algebra of five composition operations. Example code FAUST programs define a process function that operates on incoming data. This is analogous to the main function in most programming languages. The following is an example that produces silence: The second example copies the input signal to the output. It involves the _ primitive that denotes the identity function for signals: Another example sums a stereo signal into a mono signal using the + primitive: Most FAUST primitives are analogous to their C counterpart on numbers, but lifted to signals. For example, the FAUST primitive sin operates on a signal X by applying the C function sin to each sample X[t]. All C numerical functions have their counterpart in FAUST. Some signal processing primitives are specific to FAUST. For example, the delay operator @ takes two input signals: X (the signal to be delayed) and D (the delay to be applied), and produces an output signal Y such that Y(t) = X(t − D(t)). Block diagram composition Contrary to Max-like visual programming languages where the user does manual connections, FAUST primitives are assembled in block diagrams by using a set of high-level block diagram composition operations. Using the sequential composition operator : the output of + can be routed to the input of abs to compute the absolute value of the signal: Here is an example of parallel composition using the , operator that arranges its left and right expressions in parallel. This is analogous to a stereo cable. These operators can be combined arbitrarily. The following code multiplies an input signal with 0.5: The above may be rewritten in curried form: The recursive composition operator ~ can be used to create block diagrams with cycles (that include an implicit one-sample delay). Here is an example of an integrator that takes an input signal X and computes an output signal Y such that Y(t) = X(t) + Y(t−1): Generating full applications Using specific architecture files, a FAUST program can be used to produce code for a variety of platforms and plug-in formats. These architecture files act as wrappers and describe the interactions with the host audio and GUI system. As of 2021[update], more than 30 architectures are supported and new ones may be implemented by anyone. Generating block diagrams A useful option makes it possible to generate the block diagram representation of the program as one or more SVG graphic files. It is useful to note the difference between the block diagram and the generated C++ code. The key idea is not to compile the block diagram literally, but the mathematical function it denotes. Modern C/C++ compilers also don't compile programs literally. But because of the complex semantics of C/C++ (due to side effects, pointer aliasing, etc.) they can't go very far in that direction. This is a distinct advantage of a purely functional language: it allows compilers to do very advanced optimisations. Arrows-like semantics The Faust semantics is almost the same as that of Haskell Arrows type class. However, the Arrow class is not bound to signal processors. The Arrow combinators are more restrictive than their FAUST counterparts, e.g., the nesting of parallel composition is preserved, and inputs of the operands of &&& must match exactly. Awards References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Mars#cite_note-36] | [TOKENS: 11899] |
Contents Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", for its orange-red appearance. Mars is a desert-like rocky planet with a tenuous atmosphere that is primarily carbon dioxide (CO2). At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from −153 to 20 °C (−243 to 68 °F), and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, fog, frost, larger polar regions of permafrost and ice caps (with seasonal CO2 snow), but no bodies of liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. Its diameter, 6,779 km (4,212 mi), is about half the Earth's, or twice the Moon's, and its surface area is the size of all the dry land of Earth. Fine dust is prevalent across the surface and the atmosphere, being picked up and spread at the low Martian gravity even by the weak wind of the tenuous atmosphere. The terrain of Mars roughly follows a north-south divide, the Martian dichotomy, with the northern hemisphere mainly consisting of relatively flat, low lying plains, and the southern hemisphere of cratered highlands. Geologically, the planet is fairly active with marsquakes trembling underneath the ground, but also hosts many enormous volcanoes that are extinct (the tallest is Olympus Mons, 21.9 km or 13.6 mi tall), as well as one of the largest canyons in the Solar System (Valles Marineris, 4,000 km or 2,500 mi long). Mars has two natural satellites that are small and irregular in shape: Phobos and Deimos. With a significant axial tilt of 25 degrees, Mars experiences seasons, like Earth (which has an axial tilt of 23.5 degrees). A Martian solar year is equal to 1.88 Earth years (687 Earth days), a Martian solar day (sol) is equal to 24.6 hours. Mars formed along with the other planets approximately 4.5 billion years ago. During the martian Noachian period (4.5 to 3.5 billion years ago), its surface was marked by meteor impacts, valley formation, erosion, the possible presence of water oceans and the loss of its magnetosphere. The Hesperian period (beginning 3.5 billion years ago and ending 3.3–2.9 billion years ago) was dominated by widespread volcanic activity and flooding that carved immense outflow channels. The Amazonian period, which continues to the present, is the currently dominating and remaining influence on geological processes. Because of Mars's geological history, the possibility of past or present life on Mars remains an area of active scientific investigation, with some possible traces needing further examination. Being visible with the naked eye in Earth's sky as a red wandering star, Mars has been observed throughout history, acquiring diverse associations in different cultures. In 1963 the first flight to Mars took place with Mars 1, but communication was lost en route. The first successful flyby exploration of Mars was conducted in 1965 with Mariner 4. In 1971 Mariner 9 entered orbit around Mars, being the first spacecraft to orbit any body other than the Moon, Sun or Earth; following in the same year were the first uncontrolled impact (Mars 2) and first successful landing (Mars 3) on Mars. Probes have been active on Mars continuously since 1997. At times, more than ten probes have simultaneously operated in orbit or on the surface, more than at any other planet beyond Earth. Mars is an often proposed target for future crewed exploration missions, though no such mission is currently planned. Natural history Scientists have theorized that during the Solar System's formation, Mars was created as the result of a random process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points, such as chlorine, phosphorus, and sulfur, are much more common on Mars than on Earth; these elements were probably pushed outward by the young Sun's energetic solar wind. After the formation of the planets, the inner Solar System may have been subjected to the so-called Late Heavy Bombardment. About 60% of the surface of Mars shows a record of impacts from that era, whereas much of the remaining surface is probably underlain by immense impact basins caused by those events. However, more recent modeling has disputed the existence of the Late Heavy Bombardment. There is evidence of an enormous impact basin in the Northern Hemisphere of Mars, spanning 10,600 by 8,500 kilometres (6,600 by 5,300 mi), or roughly four times the size of the Moon's South Pole–Aitken basin, which would be the largest impact basin yet discovered if confirmed. It has been hypothesized that the basin was formed when Mars was struck by a Pluto-sized body about four billion years ago. The event, thought to be the cause of the Martian hemispheric dichotomy, created the smooth Borealis basin that covers 40% of the planet. A 2023 study shows evidence, based on the orbital inclination of Deimos (a small moon of Mars), that Mars may once have had a ring system 3.5 billion years to 4 billion years ago. This ring system may have been formed from a moon, 20 times more massive than Phobos, orbiting Mars billions of years ago; and Phobos would be a remnant of that ring. Epochs: The geological history of Mars can be split into many periods, but the following are the three primary periods: Geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows created about 200 million years ago. Water flows in the grabens called the Cerberus Fossae occurred less than 20 million years ago, indicating equally recent volcanic intrusions. The Mars Reconnaissance Orbiter has captured images of avalanches. Physical characteristics Mars is approximately half the diameter of Earth or twice that of the Moon, with a surface area only slightly less than the total area of Earth's dry land. Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass, resulting in about 38% of Earth's surface gravity. Mars is the only presently known example of a desert planet, a rocky planet with a surface akin to that of Earth's deserts. The red-orange appearance of the Martian surface is caused by iron(III) oxide (nanophase Fe2O3) and the iron(III) oxide-hydroxide mineral goethite. It can look like butterscotch; other common surface colors include golden, brown, tan, and greenish, depending on the minerals present. Like Earth, Mars is differentiated into a dense metallic core overlaid by less dense rocky layers. The outermost layer is the crust, which is on average about 42–56 kilometres (26–35 mi) thick, with a minimum thickness of 6 kilometres (3.7 mi) in Isidis Planitia, and a maximum thickness of 117 kilometres (73 mi) in the southern Tharsis plateau. For comparison, Earth's crust averages 27.3 ± 4.8 km in thickness. The most abundant elements in the Martian crust are silicon, oxygen, iron, magnesium, aluminum, calcium, and potassium. Mars is confirmed to be seismically active; in 2019, it was reported that InSight had detected and recorded over 450 marsquakes and related events. Beneath the crust is a silicate mantle responsible for many of the tectonic and volcanic features on the planet's surface. The upper Martian mantle is a low-velocity zone, where the velocity of seismic waves is lower than surrounding depth intervals. The mantle appears to be rigid down to the depth of about 250 km, giving Mars a very thick lithosphere compared to Earth. Below this the mantle gradually becomes more ductile, and the seismic wave velocity starts to grow again. The Martian mantle does not appear to have a thermally insulating layer analogous to Earth's lower mantle; instead, below 1050 km in depth, it becomes mineralogically similar to Earth's transition zone. At the bottom of the mantle lies a basal liquid silicate layer approximately 150–180 km thick. The Martian mantle appears to be highly heterogenous, with dense fragments up to 4 km across, likely injected deep into the planet by colossal impacts ~4.5 billion years ago; high-frequency waves from eight marsquakes slowed as they passed these localized regions, and modeling indicates the heterogeneities are compositionally distinct debris preserved because Mars lacks plate tectonics and has a sluggishly convecting interior that prevents complete homogenization. Mars's iron and nickel core is at least partially molten, and may have a solid inner core. It is around half of Mars's radius, approximately 1650–1675 km, and is enriched in light elements such as sulfur, oxygen, carbon, and hydrogen. The temperature of the core is estimated to be 2000–2400 K, compared to 5400–6230 K for Earth's solid inner core. In 2025, based on data from the InSight lander, a group of researchers reported the detection of a solid inner core 613 kilometres (381 mi) ± 67 kilometres (42 mi) in radius. Mars is a terrestrial planet with a surface that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock. The Martian surface is primarily composed of tholeiitic basalt, although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Earth, or silica glass. Regions of low albedo suggest concentrations of plagioclase feldspar, with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of the southern highlands include detectable amounts of high-calcium pyroxenes. Localized concentrations of hematite and olivine have been found. Much of the surface is deeply covered by finely grained iron(III) oxide dust. The Phoenix lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium and chlorine. These nutrients are found in soils on Earth, and are necessary for plant growth. Experiments performed by the lander showed that the Martian soil has a basic pH of 7.7, and contains 0.6% perchlorate by weight, concentrations that are toxic to humans. Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. The streaks can start in a tiny area, then spread out for hundreds of metres. They have been seen to follow the edges of boulders and other obstacles in their path. The commonly accepted hypotheses include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils. Several other explanations have been put forward, including those that involve water or even the growth of organisms. Environmental radiation levels on the surface are on average 0.64 millisieverts of radiation per day, and significantly less than the radiation of 1.84 millisieverts per day or 22 millirads per day during the flight to and from Mars. For comparison the radiation levels in low Earth orbit, where Earth's space stations orbit, are around 0.5 millisieverts of radiation per day. Hellas Planitia has the lowest surface radiation at about 0.342 millisieverts per day, featuring lava tubes southwest of Hadriacus Mons with potentially levels as low as 0.064 millisieverts per day, comparable to radiation levels during flights on Earth. Although Mars has no evidence of a structured global magnetic field, observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in the past. This paleomagnetism of magnetically susceptible minerals is similar to the alternating bands found on Earth's ocean floors. One hypothesis, published in 1999 and re-examined in October 2005 (with the help of the Mars Global Surveyor), is that these bands suggest plate tectonic activity on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded. Geography and features Although better remembered for mapping the Moon, Johann Heinrich von Mädler and Wilhelm Beer were the first areographers. They began by establishing that most of Mars's surface features were permanent and by more precisely determining the planet's rotation period. In 1840, Mädler combined ten years of observations and drew the first map of Mars. Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than roughly 50 km are named for deceased scientists and writers and others who have contributed to the study of Mars. Smaller craters are named for towns and villages of the world with populations of less than 100,000. Large valleys are named for the word "Mars" or "star" in various languages; smaller valleys are named for rivers. Large albedo features retain many of the older names but are often updated to reflect new knowledge of the nature of the features. For example, Nix Olympica (the snows of Olympus) has become Olympus Mons (Mount Olympus). The surface of Mars as seen from Earth is divided into two kinds of areas, with differing albedo. The paler plains covered with dust and sand rich in reddish iron oxides were once thought of as Martian "continents" and given names like Arabia Terra (land of Arabia) or Amazonis Planitia (Amazonian plain). The dark features were thought to be seas, hence their names Mare Erythraeum, Mare Sirenum and Aurorae Sinus. The largest dark feature seen from Earth is Syrtis Major Planum. The permanent northern polar ice cap is named Planum Boreum. The southern cap is called Planum Australe. Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich), by choice of an arbitrary point; Mädler and Beer selected a line for their first maps of Mars in 1830. After the spacecraft Mariner 9 provided extensive imagery of Mars in 1972, a small crater (later called Airy-0), located in the Sinus Meridiani ("Middle Bay" or "Meridian Bay"), was chosen by Merton E. Davies, Harold Masursky, and Gérard de Vaucouleurs for the definition of 0.0° longitude to coincide with the original selection. Because Mars has no oceans, and hence no "sea level", a zero-elevation surface had to be selected as a reference level; this is called the areoid of Mars, analogous to the terrestrial geoid. Zero altitude was defined by the height at which there is 610.5 Pa (6.105 mbar) of atmospheric pressure. This pressure corresponds to the triple point of water, and it is about 0.6% of the sea level surface pressure on Earth (0.006 atm). For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty cartographic quadrangles, each named for a classical albedo feature it contains. In April 2023, The New York Times reported an updated global map of Mars based on images from the Hope spacecraft. A related, but much more detailed, global Mars map was released by NASA on 16 April 2023. The vast upland region Tharsis contains several massive volcanoes, which include the shield volcano Olympus Mons. The edifice is over 600 km (370 mi) wide. Because the mountain is so large, with complex structure at its edges, giving a definite height to it is difficult. Its local relief, from the foot of the cliffs which form its northwest margin to its peak, is over 21 km (13 mi), a little over twice the height of Mauna Kea as measured from its base on the ocean floor. The total elevation change from the plains of Amazonis Planitia, over 1,000 km (620 mi) to the northwest, to the summit approaches 26 km (16 mi), roughly three times the height of Mount Everest, which in comparison stands at just over 8.8 kilometres (5.5 mi). Consequently, Olympus Mons is either the tallest or second-tallest mountain in the Solar System; the only known mountain which might be taller is the Rheasilvia peak on the asteroid Vesta, at 20–25 km (12–16 mi). The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. It is possible that, four billion years ago, the Northern Hemisphere of Mars was struck by an object one-tenth to two-thirds the size of Earth's Moon. If this is the case, the Northern Hemisphere of Mars would be the site of an impact crater 10,600 by 8,500 kilometres (6,600 by 5,300 mi) in size, or roughly the area of Europe, Asia, and Australia combined, surpassing Utopia Planitia and the Moon's South Pole–Aitken basin as the largest impact crater in the Solar System. Mars is scarred by 43,000 impact craters with a diameter of 5 kilometres (3.1 mi) or greater. The largest exposed crater is Hellas, which is 2,300 kilometres (1,400 mi) wide and 7,000 metres (23,000 ft) deep, and is a light albedo feature clearly visible from Earth. There are other notable impact features, such as Argyre, which is around 1,800 kilometres (1,100 mi) in diameter, and Isidis, which is around 1,500 kilometres (930 mi) in diameter. Due to the smaller mass and size of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets, i.e., those that lie within the orbit of Jupiter. Martian craters can[discuss] have a morphology that suggests the ground became wet after the meteor impact. The large canyon, Valles Marineris (Latin for 'Mariner Valleys, also known as Agathodaemon in the old canal maps), has a length of 4,000 kilometres (2,500 mi) and a depth of up to 7 kilometres (4.3 mi). The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon on Earth is only 446 kilometres (277 mi) long and nearly 2 kilometres (1.2 mi) deep. Valles Marineris was formed due to the swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where 150 kilometres (93 mi) of transverse motion has occurred, making Mars a planet with possibly a two-tectonic plate arrangement. Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons. The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters". Cave entrances measure from 100 to 252 metres (328 to 827 ft) wide and they are estimated to be at least 73 to 96 metres (240 to 315 ft) deep. Because light does not reach the floor of most of the caves, they may extend much deeper than these lower estimates and widen below the surface. "Dena" is the only exception; its floor is visible and was measured to be 130 metres (430 ft) deep. The interiors of these caverns may be protected from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface. Martian geysers (or CO2 jets) are putative sites of small gas and dust eruptions that occur in the south polar region of Mars during the spring thaw. "Dark dune spots" and "spiders" – or araneiforms – are the two most visible types of features ascribed to these eruptions. Similarly sized dust will settle from the thinner Martian atmosphere sooner than it would on Earth. For example, the dust suspended by the 2001 global dust storms on Mars only remained in the Martian atmosphere for 0.6 years, while the dust from Mount Pinatubo took about two years to settle. However, under current Martian conditions, the mass movements involved are generally much smaller than on Earth. Even the 2001 global dust storms on Mars moved only the equivalent of a very thin dust layer – about 3 μm thick if deposited with uniform thickness between 58° north and south of the equator. Dust deposition at the two rover sites has proceeded at a rate of about the thickness of a grain every 100 sols. Atmosphere Mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer. Both Mars Global Surveyor and Mars Express have detected ionized atmospheric particles trailing off into space behind Mars, and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied. Atmospheric pressure on the surface today ranges from a low of 30 Pa (0.0044 psi) on Olympus Mons to over 1,155 Pa (0.1675 psi) in Hellas Planitia, with a mean pressure at the surface level of 600 Pa (0.087 psi). The highest atmospheric density on Mars is equal to that found 35 kilometres (22 mi) above Earth's surface. The resulting mean surface pressure is only 0.6% of Earth's 101.3 kPa (14.69 psi). The scale height of the atmosphere is about 10.8 kilometres (6.7 mi), which is higher than Earth's 6 kilometres (3.7 mi), because the surface gravity of Mars is only about 38% of Earth's. The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water. The atmosphere is quite dusty, containing particulates about 1.5 μm in diameter which give the Martian sky a tawny color when seen from the surface. It may take on a pink hue due to iron oxide particles suspended in it. Despite repeated detections of methane on Mars, there is no scientific consensus as to its origin. One suggestion is that methane exists on Mars and that its concentration fluctuates seasonally. The existence of methane could be produced by non-biological process such as serpentinization involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars, or by Martian life. Compared to Earth, its higher concentration of atmospheric CO2 and lower surface pressure may be why sound is attenuated more on Mars, where natural sources are rare apart from the wind. Using acoustic recordings collected by the Perseverance rover, researchers concluded that the speed of sound there is approximately 240 m/s for frequencies below 240 Hz, and 250 m/s for those above. Auroras have been detected on Mars. Because Mars lacks a global magnetic field, the types and distribution of auroras there differ from those on Earth; rather than being mostly restricted to polar regions as is the case on Earth, a Martian aurora can encompass the planet. In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled, and were associated with an aurora 25 times brighter than any observed earlier, due to a massive, and unexpected, solar storm in the middle of the month. Mars has seasons, alternating between its northern and southern hemispheres, similar to on Earth. Additionally the orbit of Mars has, compared to Earth's, a large eccentricity and approaches perihelion when it is summer in its southern hemisphere and winter in its northern, and aphelion when it is winter in its southern hemisphere and summer in its northern. As a result, the seasons in its southern hemisphere are more extreme and the seasons in its northern are milder than would otherwise be the case. The summer temperatures in the south can be warmer than the equivalent summer temperatures in the north by up to 30 °C (54 °F). Martian surface temperatures vary from lows of about −110 °C (−166 °F) to highs of up to 35 °C (95 °F) in equatorial summer. The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure (about 1% that of the atmosphere of Earth), and the low thermal inertia of Martian soil. The planet is 1.52 times as far from the Sun as Earth, resulting in just 43% of the amount of sunlight. Mars has the largest dust storms in the Solar System, reaching speeds of over 160 km/h (100 mph). These can vary from a storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase global temperature. Seasons also produce dry ice covering polar ice caps. Hydrology While Mars contains water in larger amounts, most of it is dust covered water ice at the Martian polar ice caps. The volume of water ice in the south polar ice cap, if melted, would be enough to cover most of the surface of the planet with a depth of 11 metres (36 ft). Water in its liquid form cannot persist on the surface due to Mars's low atmospheric pressure, which is less than 1% that of Earth. Only at the lowest of elevations are the pressure and temperature high enough for liquid water to exist for short periods. Although little water is present in the atmosphere, there is enough to produce clouds of water ice and different cases of snow and frost, often mixed with snow of carbon dioxide dry ice. Landforms visible on Mars strongly suggest that liquid water has existed on the planet's surface. Huge linear swathes of scoured ground, known as outflow channels, cut across the surface in about 25 places. These are thought to be a record of erosion caused by the catastrophic release of water from subsurface aquifers, though some of these structures have been hypothesized to result from the action of glaciers or lava. One of the larger examples, Ma'adim Vallis, is 700 kilometres (430 mi) long, much greater than the Grand Canyon, with a width of 20 kilometres (12 mi) and a depth of 2 kilometres (1.2 mi) in places. It is thought to have been carved by flowing water early in Mars's history. The youngest of these channels is thought to have formed only a few million years ago. Elsewhere, particularly on the oldest areas of the Martian surface, finer-scale, dendritic networks of valleys are spread across significant proportions of the landscape. Features of these valleys and their distribution strongly imply that they were carved by runoff resulting from precipitation in early Mars history. Subsurface water flow and groundwater sapping may play important subsidiary roles in some networks, but precipitation was probably the root cause of the incision in almost all cases. Along craters and canyon walls, there are thousands of features that appear similar to terrestrial gullies. The gullies tend to be in the highlands of the Southern Hemisphere and face the Equator; all are poleward of 30° latitude. A number of authors have suggested that their formation process involves liquid water, probably from melting ice, although others have argued for formation mechanisms involving carbon dioxide frost or the movement of dry dust. No partially degraded gullies have formed by weathering and no superimposed impact craters have been observed, indicating that these are young features, possibly still active. Other geological features, such as deltas and alluvial fans preserved in craters, are further evidence for warmer, wetter conditions at an interval or intervals in earlier Mars history. Such conditions necessarily require the widespread presence of crater lakes across a large proportion of the surface, for which there is independent mineralogical, sedimentological and geomorphological evidence. Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite, both of which sometimes form in the presence of water. The chemical signature of water vapor on Mars was first unequivocally demonstrated in 1963 by spectroscopy using an Earth-based telescope. In 2004, Opportunity detected the mineral jarosite. This forms only in the presence of acidic water, showing that water once existed on Mars. The Spirit rover found concentrated deposits of silica in 2007 that indicated wet conditions in the past, and in December 2011, the mineral gypsum, which also forms in the presence of water, was found on the surface by NASA's Mars rover Opportunity. It is estimated that the amount of water in the upper mantle of Mars, represented by hydroxyl ions contained within Martian minerals, is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of 200–1,000 metres (660–3,280 ft). On 18 March 2013, NASA reported evidence from instruments on the Curiosity rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock. Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of 60 centimetres (24 in), during the rover's traverse from the Bradbury Landing site to the Yellowknife Bay area in the Glenelg terrain. In September 2015, NASA announced that they had found strong evidence of hydrated brine flows in recurring slope lineae, based on spectrometer readings of the darkened areas of slopes. These streaks flow downhill in Martian summer, when the temperature is above −23 °C, and freeze at lower temperatures. These observations supported earlier hypotheses, based on timing of formation and their rate of growth, that these dark streaks resulted from water flowing just below the surface. However, later work suggested that the lineae may be dry, granular flows instead, with at most a limited role for water in initiating the process. A definitive conclusion about the presence, extent, and role of liquid water on the Martian surface remains elusive. Researchers suspect much of the low northern plains of the planet were covered with an ocean hundreds of meters deep, though this theory remains controversial. In March 2015, scientists stated that such an ocean might have been the size of Earth's Arctic Ocean. This finding was derived from the ratio of protium to deuterium in the modern Martian atmosphere compared to that ratio on Earth. The amount of Martian deuterium (D/H = 9.3 ± 1.7 10−4) is five to seven times the amount on Earth (D/H = 1.56 10−4), suggesting that ancient Mars had significantly higher levels of water. Results from the Curiosity rover had previously found a high ratio of deuterium in Gale Crater, though not significantly high enough to suggest the former presence of an ocean. Other scientists caution that these results have not been confirmed, and point out that Martian climate models have not yet shown that the planet was warm enough in the past to support bodies of liquid water. Near the northern polar cap is the 81.4 kilometres (50.6 mi) wide Korolev Crater, which the Mars Express orbiter found to be filled with approximately 2,200 cubic kilometres (530 cu mi) of water ice. In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior (which is 12,100 cubic kilometers). During observations from 2018 through 2021, the ExoMars Trace Gas Orbiter spotted indications of water, probably subsurface ice, in the Valles Marineris canyon system. Orbital motion Mars's average distance from the Sun is roughly 230 million km (143 million mi), and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds. A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours. The gravitational potential difference and thus the delta-v needed to transfer between Mars and Earth is the second lowest for Earth. The axial tilt of Mars is 25.19° relative to its orbital plane, which is similar to the axial tilt of Earth. As a result, Mars has seasons like Earth, though on Mars they are nearly twice as long because its orbital period is that much longer. In the present day, the orientation of the north pole of Mars is close to the star Deneb. Mars has a relatively pronounced orbital eccentricity of about 0.09; of the seven other planets in the Solar System, only Mercury has a larger orbital eccentricity. It is known that in the past, Mars has had a much more circular orbit. At one point, 1.35 million Earth years ago, Mars had an eccentricity of roughly 0.002, much less than that of Earth today. Mars's cycle of eccentricity is 96,000 Earth years compared to Earth's cycle of 100,000 years. Mars has its closest approach to Earth (opposition) in a synodic period of 779.94 days. It should not be confused with Mars conjunction, where the Earth and Mars are at opposite sides of the Solar System and form a straight line crossing the Sun. The average time between the successive oppositions of Mars, its synodic period, is 780 days; but the number of days between successive oppositions can range from 764 to 812. The distance at close approach varies between about 54 and 103 million km (34 and 64 million mi) due to the planets' elliptical orbits, which causes comparable variation in angular size. At their furthest Mars and Earth can be as far as 401 million km (249 million mi) apart. Mars comes into opposition from Earth every 2.1 years. The planets come into opposition near Mars's perihelion in 2003, 2018 and 2035, with the 2020 and 2033 events being particularly close to perihelic opposition. The mean apparent magnitude of Mars is +0.71 with a standard deviation of 1.05. Because the orbit of Mars is eccentric, the magnitude at opposition from the Sun can range from about −3.0 to −1.4. The minimum brightness is magnitude +1.86 when the planet is near aphelion and in conjunction with the Sun. At its brightest, Mars (along with Jupiter) is second only to Venus in apparent brightness. Mars usually appears distinctly yellow, orange, or red. When farthest away from Earth, it is more than seven times farther away than when it is closest. Mars is usually close enough for particularly good viewing once or twice at 15-year or 17-year intervals. Optical ground-based telescopes are typically limited to resolving features about 300 kilometres (190 mi) across when Earth and Mars are closest because of Earth's atmosphere. As Mars approaches opposition, it begins a period of retrograde motion, which means it will appear to move backwards in a looping curve with respect to the background stars. This retrograde motion lasts for about 72 days, and Mars reaches its peak apparent brightness in the middle of this interval. Moons Mars has two relatively small (compared to Earth's) natural moons, Phobos (about 22 km (14 mi) in diameter) and Deimos (about 12 km (7.5 mi) in diameter), which orbit at 9,376 km (5,826 mi) and 23,460 km (14,580 mi) around the planet. The origin of both moons is unclear, although a popular theory states that they were asteroids captured into Martian orbit. Both satellites were discovered in 1877 by Asaph Hall and were named after the characters Phobos (the deity of panic and fear) and Deimos (the deity of terror and dread), twins from Greek mythology who accompanied their father Ares, god of war, into battle. Mars was the Roman equivalent to Ares. In modern Greek, the planet retains its ancient name Ares (Aris: Άρης). From the surface of Mars, the motions of Phobos and Deimos appear different from that of the Earth's satellite, the Moon. Phobos rises in the west, sets in the east, and rises again in just 11 hours. Deimos, being only just outside synchronous orbit – where the orbital period would match the planet's period of rotation – rises as expected in the east, but slowly. Because the orbit of Phobos is below a synchronous altitude, tidal forces from Mars are gradually lowering its orbit. In about 50 million years, it could either crash into Mars's surface or break up into a ring structure around the planet. The origin of the two satellites is not well understood. Their low albedo and carbonaceous chondrite composition have been regarded as similar to asteroids, supporting a capture theory. The unstable orbit of Phobos would seem to point toward a relatively recent capture. But both have circular orbits near the equator, which is unusual for captured objects, and the required capture dynamics are complex. Accretion early in the history of Mars is plausible, but would not account for a composition resembling asteroids rather than Mars itself, if that is confirmed. Mars may have yet-undiscovered moons, smaller than 50 to 100 metres (160 to 330 ft) in diameter, and a dust ring is predicted to exist between Phobos and Deimos. A third possibility for their origin as satellites of Mars is the involvement of a third body or a type of impact disruption. More-recent lines of evidence for Phobos having a highly porous interior, and suggesting a composition containing mainly phyllosilicates and other minerals known from Mars, point toward an origin of Phobos from material ejected by an impact on Mars that reaccreted in Martian orbit, similar to the prevailing theory for the origin of Earth's satellite. Although the visible and near-infrared (VNIR) spectra of the moons of Mars resemble those of outer-belt asteroids, the thermal infrared spectra of Phobos are reported to be inconsistent with chondrites of any class. It is also possible that Phobos and Deimos were fragments of an older moon, formed by debris from a large impact on Mars, and then destroyed by a more recent impact upon the satellite. More recently, a study conducted by a team of researchers from multiple countries suggests that a lost moon, at least fifteen times the size of Phobos, may have existed in the past. By analyzing rocks which point to tidal processes on the planet, it is possible that these tides may have been regulated by a past moon. Human observations and exploration The history of observations of Mars is marked by oppositions of Mars when the planet is closest to Earth and hence is most easily visible, which occur every couple of years. Even more notable are the perihelic oppositions of Mars, which are distinguished because Mars is close to perihelion, making it even closer to Earth. The ancient Sumerians named Mars Nergal, the god of war and plague. During Sumerian times, Nergal was a minor deity of little significance, but, during later times, his main cult center was the city of Nineveh. In Mesopotamian texts, Mars is referred to as the "star of judgement of the fate of the dead". The existence of Mars as a wandering object in the night sky was also recorded by the ancient Egyptian astronomers and, by 1534 BCE, they were familiar with the retrograde motion of the planet. By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They invented arithmetic methods for making minor corrections to the predicted positions of the planets. In Ancient Greece, the planet was known as Πυρόεις. Commonly, the Greek name for the planet now referred to as Mars, was Ares. It was the Romans who named the planet Mars, for their god of war, often represented by the sword and shield of the planet's namesake. In the fourth century BCE, Aristotle noted that Mars disappeared behind the Moon during an occultation, indicating that the planet was farther away. Ptolemy, a Greek living in Alexandria, attempted to address the problem of the orbital motion of Mars. Ptolemy's model and his collective work on astronomy was presented in the multi-volume collection later called the Almagest (from the Arabic for "greatest"), which became the authoritative treatise on Western astronomy for the next fourteen centuries. Literature from ancient China confirms that Mars was known by Chinese astronomers by no later than the fourth century BCE. In the East Asian cultures, Mars is traditionally referred to as the "fire star" (火星) based on the Wuxing system. In 1609 Johannes Kepler published a 10 year study of Martian orbit, using the diurnal parallax of Mars, measured by Tycho Brahe, to make a preliminary calculation of the relative distance to the planet. From Brahe's observations of Mars, Kepler deduced that the planet orbited the Sun not in a circle, but in an ellipse. Moreover, Kepler showed that Mars sped up as it approached the Sun and slowed down as it moved farther away, in a manner that later physicists would explain as a consequence of the conservation of angular momentum.: 433–437 In 1610 the first use of a telescope for astronomical observation, including Mars, was performed by Italian astronomer Galileo Galilei. With the telescope the diurnal parallax of Mars was again measured in an effort to determine the Sun-Earth distance. This was first performed by Giovanni Domenico Cassini in 1672. The early parallax measurements were hampered by the quality of the instruments. The only occultation of Mars by Venus observed was that of 13 October 1590, seen by Michael Maestlin at Heidelberg. By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. On 5 September 1877, a perihelic opposition to Mars occurred. The Italian astronomer Giovanni Schiaparelli used a 22-centimetre (8.7 in) telescope in Milan to help produce the first detailed map of Mars. These maps notably contained features he called canali, which, with the possible exception of the natural canyon Valles Marineris, were later shown to be an optical illusion. These canali were supposedly long, straight lines on the surface of Mars, to which he gave names of famous rivers on Earth. His term, which means "channels" or "grooves", was popularly mistranslated in English as "canals". Influenced by the observations, the orientalist Percival Lowell founded an observatory which had 30- and 45-centimetre (12- and 18-in) telescopes. The observatory was used for the exploration of Mars during the last good opportunity in 1894, and the following less favorable oppositions. He published several books on Mars and life on the planet, which had a great influence on the public. The canali were independently observed by other astronomers, like Henri Joseph Perrotin and Louis Thollon in Nice, using one of the largest telescopes of that time. The seasonal changes (consisting of the diminishing of the polar caps and the dark areas formed during Martian summers) in combination with the canals led to speculation about life on Mars, and it was a long-held belief that Mars contained vast seas and vegetation. As bigger telescopes were used, fewer long, straight canali were observed. During observations in 1909 by Antoniadi with an 84-centimetre (33 in) telescope, irregular patterns were observed, but no canali were seen. The first spacecraft from Earth to visit Mars was Mars 1 of the Soviet Union, which flew by in 1963, but contact was lost en route. NASA's Mariner 4 followed and became the first spacecraft to successfully transmit from Mars; launched on 28 November 1964, it made its closest approach to the planet on 15 July 1965. Mariner 4 detected the weak Martian radiation belt, measured at about 0.1% that of Earth, and captured the first images of another planet from deep space. Once spacecraft visited the planet during the 1960s and 1970s, many previous concepts of Mars were radically broken. After the results of the Viking life-detection experiments, the hypothesis of a dead planet was generally accepted. The data from Mariner 9 and Viking allowed better maps of Mars to be made. Until 1997 and after Viking 1 shut down in 1982, Mars was only visited by three unsuccessful probes, two flying past without contact (Phobos 1, 1988; Mars Observer, 1993), and one (Phobos 2 1989) malfunctioning in orbit before reaching its destination Phobos. In 1997 Mars Pathfinder became the first successful rover mission beyond the Moon and started together with Mars Global Surveyor (operated until late 2006) an uninterrupted active robotic presence at Mars that has lasted until today. It produced complete, extremely detailed maps of the Martian topography, magnetic field and surface minerals. Starting with these missions a range of new improved crewless spacecraft, including orbiters, landers, and rovers, have been sent to Mars, with successful missions by the NASA (United States), Jaxa (Japan), ESA, United Kingdom, ISRO (India), Roscosmos (Russia), the United Arab Emirates, and CNSA (China) to study the planet's surface, climate, and geology, uncovering the different elements of the history and dynamic of the hydrosphere of Mars and possible traces of ancient life. As of 2023[update], Mars is host to ten functioning spacecraft. Eight are in orbit: 2001 Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN, ExoMars Trace Gas Orbiter, the Hope orbiter, and the Tianwen-1 orbiter. Another two are on the surface: the Mars Science Laboratory Curiosity rover and the Perseverance rover. Collected maps are available online at websites including Google Mars. NASA provides two online tools: Mars Trek, which provides visualizations of the planet using data from 50 years of exploration, and Experience Curiosity, which simulates traveling on Mars in 3-D with Curiosity. Planned missions to Mars include: As of February 2024[update], debris from these types of missions has reached over seven tons. Most of it consists of crashed and inactive spacecraft as well as discarded components. In April 2024, NASA selected several companies to begin studies on providing commercial services to further enable robotic science on Mars. Key areas include establishing telecommunications, payload delivery and surface imaging. Habitability and habitation During the late 19th century, it was widely accepted in the astronomical community that Mars had life-supporting qualities, including the presence of oxygen and water. However, in 1894 W. W. Campbell at Lick Observatory observed the planet and found that "if water vapor or oxygen occur in the atmosphere of Mars it is in quantities too small to be detected by spectroscopes then available". That observation contradicted many of the measurements of the time and was not widely accepted. Campbell and V. M. Slipher repeated the study in 1909 using better instruments, but with the same results. It was not until the findings were confirmed by W. S. Adams in 1925 that the myth of the Earth-like habitability of Mars was finally broken. However, even in the 1960s, articles were published on Martian biology, putting aside explanations other than life for the seasonal changes on Mars. The current understanding of planetary habitability – the ability of a world to develop environmental conditions favorable to the emergence of life – favors planets that have liquid water on their surface. Most often this requires the orbit of a planet to lie within the habitable zone, which for the Sun is estimated to extend from within the orbit of Earth to about that of Mars. During perihelion, Mars dips inside this region, but Mars's thin (low-pressure) atmosphere prevents liquid water from existing over large regions for extended periods. The past flow of liquid water demonstrates the planet's potential for habitability. Recent evidence has suggested that any water on the Martian surface may have been too salty and acidic to support regular terrestrial life. The environmental conditions on Mars are a challenge to sustaining organic life: the planet has little heat transfer across its surface, it has poor insulation against bombardment by the solar wind due to the absence of a magnetosphere and has insufficient atmospheric pressure to retain water in a liquid form (water instead sublimes to a gaseous state). Mars is nearly, or perhaps totally, geologically dead; the end of volcanic activity has apparently stopped the recycling of chemicals and minerals between the surface and interior of the planet. Evidence suggests that the planet was once significantly more habitable than it is today, but whether living organisms ever existed there remains unknown. The Viking probes of the mid-1970s carried experiments designed to detect microorganisms in Martian soil at their respective landing sites and had positive results, including a temporary increase in CO2 production on exposure to water and nutrients. This sign of life was later disputed by scientists, resulting in a continuing debate, with NASA scientist Gilbert Levin asserting that Viking may have found life. A 2014 analysis of Martian meteorite EETA79001 found chlorate, perchlorate, and nitrate ions in sufficiently high concentrations to suggest that they are widespread on Mars. UV and X-ray radiation would turn chlorate and perchlorate ions into other, highly reactive oxychlorines, indicating that any organic molecules would have to be buried under the surface to survive. Small quantities of methane and formaldehyde detected by Mars orbiters are both claimed to be possible evidence for life, as these chemical compounds would quickly break down in the Martian atmosphere. Alternatively, these compounds may instead be replenished by volcanic or other geological means, such as serpentinite. Impact glass, formed by the impact of meteors, which on Earth can preserve signs of life, has also been found on the surface of the impact craters on Mars. Likewise, the glass in impact craters on Mars could have preserved signs of life, if life existed at the site. The Cheyava Falls rock discovered on Mars in June 2024 has been designated by NASA as a "potential biosignature" and was core sampled by the Perseverance rover for possible return to Earth and further examination. Although highly intriguing, no definitive final determination on a biological or abiotic origin of this rock can be made with the data currently available. Several plans for a human mission to Mars have been proposed, but none have come to fruition. The NASA Authorization Act of 2017 directed NASA to study the feasibility of a crewed Mars mission in the early 2030s; the resulting report concluded that this would be unfeasible. In addition, in 2021, China was planning to send a crewed Mars mission in 2033. Privately held companies such as SpaceX have also proposed plans to send humans to Mars, with the eventual goal to settle on the planet. As of 2024, SpaceX has proceeded with the development of the Starship launch vehicle with the goal of Mars colonization. In plans shared with the company in April 2024, Elon Musk envisions the beginning of a Mars colony within the next twenty years. This would be enabled by the planned mass manufacturing of Starship and initially sustained by resupply from Earth, and in situ resource utilization on Mars, until the Mars colony reaches full self sustainability. Any future human mission to Mars will likely take place within the optimal Mars launch window, which occurs every 26 months. The moon Phobos has been proposed as an anchor point for a space elevator. Besides national space agencies and space companies, groups such as the Mars Society and The Planetary Society advocate for human missions to Mars. In culture Mars is named after the Roman god of war (Greek Ares), but was also associated with the demi-god Heracles (Roman Hercules) by ancient Greek astronomers, as detailed by Aristotle. This association between Mars and war dates back at least to Babylonian astronomy, in which the planet was named for the god Nergal, deity of war and destruction. It persisted into modern times, as exemplified by Gustav Holst's orchestral suite The Planets, whose famous first movement labels Mars "The Bringer of War". The planet's symbol, a circle with a spear pointing out to the upper right, is also used as a symbol for the male gender. The symbol dates from at least the 11th century, though a possible predecessor has been found in the Greek Oxyrhynchus Papyri. The idea that Mars was populated by intelligent Martians became widespread in the late 19th century. Schiaparelli's "canali" observations combined with Percival Lowell's books on the subject put forward the standard notion of a planet that was a drying, cooling, dying world with ancient civilizations constructing irrigation works. Many other observations and proclamations by notable personalities added to what has been termed "Mars Fever". In the present day, high-resolution mapping of the surface of Mars has revealed no artifacts of habitation, but pseudoscientific speculation about intelligent life on Mars still continues. Reminiscent of the canali observations, these speculations are based on small scale features perceived in the spacecraft images, such as "pyramids" and the "Face on Mars". In his book Cosmos, planetary astronomer Carl Sagan wrote: "Mars has become a kind of mythic arena onto which we have projected our Earthly hopes and fears." The depiction of Mars in fiction has been stimulated by its dramatic red color and by nineteenth-century scientific speculations that its surface conditions might support not just life but intelligent life. This gave way to many science fiction stories involving these concepts, such as H. G. Wells's The War of the Worlds, in which Martians seek to escape their dying planet by invading Earth; Ray Bradbury's The Martian Chronicles, in which human explorers accidentally destroy a Martian civilization; as well as Edgar Rice Burroughs's series Barsoom, C. S. Lewis's novel Out of the Silent Planet (1938), and a number of Robert A. Heinlein stories before the mid-sixties. Since then, depictions of Martians have also extended to animation. A comic figure of an intelligent Martian, Marvin the Martian, appeared in Haredevil Hare (1948) as a character in the Looney Tunes animated cartoons of Warner Brothers, and has continued as part of popular culture to the present. After the Mariner and Viking spacecraft had returned pictures of Mars as a lifeless and canal-less world, these ideas about Mars were abandoned; for many science-fiction authors, the new discoveries initially seemed like a constraint, but eventually the post-Viking knowledge of Mars became itself a source of inspiration for works like Kim Stanley Robinson's Mars trilogy. See also Notes References Further reading External links Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Local Sheet → Local Volume → Virgo Supercluster → Laniakea Supercluster → Pisces–Cetus Supercluster Complex → Local Hole → Observable universe → UniverseEach arrow (→) may be read as "within" or "part of". |
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[SOURCE: https://en.wikipedia.org/wiki/Legislative] | [TOKENS: 2992] |
Contents Legislature A legislature (UK: /ˈlɛdʒɪslətʃər/, US: /-ˌleɪtʃər/) is a deliberative assembly that holds the legal authority to make law and exercise political oversight within a political entity such as a state, nation, or city. Legislatures are among the principal institutions of state, typically contrasted with the executive and judicial institutions. They may exist at different levels of governance—national, subnational (state, provincial, or regional), local, or supranational—such as the European Parliament. In most political systems, the laws enacted by legislatures are referred to as primary legislation. Legislatures may also perform oversight, budgetary, and representative functions. Members of a legislature, called legislators, may be elected, indirectly chosen, or appointed, and legislatures may be unicameral, bicameral, or multicameral, depending on their constitutional design. There are several types of legislatures, reflecting the different constitutional principles of power on which states are organized. These types illustrate how legislatures differ not only in structure and function, but also in their constitutional relationship to other state institutions and in the theories of sovereignty and power that underpin them. The most common types are parliaments, which operate under the fusion of powers between the executive and the legislature; congresses, which function under the separation of powers between independent branches of government—in these systems, the legislature is institutionally separate from the other branches and has limited means to influence their operations; and supreme state organs of power, found in communist states, which operated under the doctrine of unified power, centralizing executive, legislative, judicial and all other state powers in a supreme state organ of power, with subordinate organs carrying out delegated functions within a constitutionally defined division of labour among state organs. Types of legislatures There exist different types of legislatures. In liberal democratic systems, there exist two: parliaments and congress legislatures. Unlike parliament, there are no commonly agreed-upon terms for legislatures in non-parliamentary liberal democracies. Parliaments exist in states that practice the fusion of powers, while congresses exist in states that practice the separation of powers. There also exist other types of legislatures, such as the supreme state organs of power (SSOP) in communist states, which function within the bounds of unified power. Types of legislatures are defined by, as shown, the political power system they operate in. These power principles say something about the relationship between the legislature and other state institutions. For example, that the United Kingdom has a Parliament means that it practices fusion of powers, while Mexico's Congress of the Union informs that Mexico practices the separation of powers. According to scholar Amie Kreppel, the most important distinguishing feature between a type of legislature is the relationship between the legislature and the executive. In liberal democratic states that practice parliamentary democracy, the government in the form of the prime minister and the cabinet is elected by the legislature. The members of the government are elected from within the membership of parliament. Additionally, although an institutionally distinct organ, the government is accountable to parliament. Meaning that, theoretically, the legislature can remove the government as it sees fit, regardless of electoral outcomes. However, the removal of a government by the legislature can lead to early elections and result in both losing power in the coming election. Therefore, the relationship between the legislature and government in a parliamentary democracy is characterised by mutual dependence. The boundaries between government branches are clearly demarcated in separation of powers systems. In contrast to parliamentary systems, in separation of powers systems, the head of state and head of government are merged into an executive branch in the office of president. Also, to clarify the institutional boundary even further, the president and the congressional legislature are elected in separate elections. For these reasons, the ability of congress to remove the executive is limited. It can instigate, as in the United States, an impeachment of the executive, but that is considered to be a move only taken in the utmost extreme circumstances. Communist states established SSOPs, and formally speaking, these organs are the most powerful state institutions in the respective country. Since it's a holder of the unified powers of the state, the SSOP is constrained only by the limits it has itself set by constitutional and legal documents it has adopted. For example, in China, according to Chinese legal scholar Zhou Fang, "[t]he powers of the National People's Congress as the [SSOP] are boundless, its authority extends to the entire territory of the country, and, if necessary, it can intervene in any matter which it finds it requisite to do so." More specifically, according to Chinese legal scholars Xu Chongde and Niu Wenzhan, "[t]he other central State organs are created by [China's SSOP] and execute the laws and resolutions made by [China's SSOP]." According to scholar Georg Brunner, this indicates that communist constitutions codify the state's unlimited political powers, and indirectly, those of the ruling communist party. He believes this is proof that the liberal democratic conception of the rule of law is irreconcilable with communist state constitutions because they rest on opposing relationships between law and politics. Under the liberal democratic rule of law conception, political processes are constrained by legal norms supervised by an independent judiciary and are viewed as universal and non-ideological. That means that holders of political power are bound by law, and that law takes precedence over politics. By contrast, communist constitutions codify the primacy of politics over judicial authority, as judicial power is also considered a form of political power. That means that communist states formally subjugate judicial power to the political power of the SSOP (the supreme judicial organ is inferior and accountable to the SSOP). Marxist–Leninists hold that legislation, not judicial rulings, is the sole source of valid law. As a result, Marxism–Leninism rejects the separation of powers, but supports the demarcation of state responsibilities in accordance with the principle of the division of labour. Other state organs derive their powers from, and are subordinated to, the SSOP. Terminology The name used to refer to a legislative body varies by country. Common names include: By names: By languages: Though the specific roles for each legislature differ by location, they all aim to serve the same purpose of appointing officials to represent their citizens to determine appropriate legislation for the country. History Among the earliest recognised formal legislatures was the Athenian Ecclesia. In the Middle Ages, European monarchs would host assemblies of the nobility, which would later develop into predecessors of modern legislatures. These were often named the Estates. The oldest surviving legislature is the Icelandic Althing, founded in 930 CE. Functions Democratic legislatures have six major functions: representation, deliberation, legislation, authorizing expenditure, making governments, and oversight. There exist five ways that representation can be achieved in a legislature: One of the major functions of a legislature is to discuss and debate issues of major importance to society. This activity can take place in two forms. In debating legislatures, such as the Parliament of the United Kingdom, the floor of the legislature frequently sees lively debate. In contrast, in committee-based legislatures like the United States Congress, deliberation takes place in closed committees. While legislatures have nominally the sole power to create laws, the substantive extent of this power depends on details of the political system. In Westminster-style legislatures the executive (composed of the cabinet) can essentially pass any laws it wants, as it usually has a majority of legislators behind it, kept in check by the party whip, while committee-based legislatures in continental Europe and those in presidential systems of the Americas have more independence in drafting and amending bills. According to the median voter theorem laws aligned with the opinion of median voters increase political responsiveness. The origins of the power of the purse which legislatures ordinarily have in passing or denying government budgets goes back to the European assemblies of nobility which the monarchs would have to consult before raising taxes. For this power to be actually effective, the legislature should be able to amend the budget, have an effective committee system, enough time for consideration, as well as access to relevant background information. There are several ways in which the legislature can hold the executive branch (the administration or government) accountable. This can be done through hearings, questioning, interpellations, votes of confidence, the formation of committees. Parliaments are usually ensured with upholding the rule of law, verifying that public funds are used accountably and efficiently as well as make government processes transparent and actions so that they can be debated by the public and its representatives. Agora notes that parliamentary systems or political parties in which political leaders can influence or decide which members receive top jobs can lead to passivity amongst members of the party and less challenging of leadership. Agora notes that this phenomenon is acute if the election of a member is dependent on the support of political leadership. In contrast to democratic systems, legislatures under authoritarianism are used to ensure the stability of the power structure by co-opting potential competing interests within the elites, which they achieve by: Internal organization Each chamber of the legislature consists of a number of legislators who use some form of parliamentary procedure to debate political issues and vote on proposed legislation. There must be a certain number of legislators present to carry out these activities; this is called a quorum. Some of the responsibilities of a legislature, such as giving first consideration to newly proposed legislation, are usually delegated to committees made up of a few of the members of the chamber(s). The members of a legislature usually represent different political parties; the members from each party generally meet as a caucus to organize their internal affairs. Relation to other branches of government Legislatures vary widely in the amount of political power they wield, compared to other political players such as judiciaries, militaries, and executives. In 2009, political scientists M. Steven Fish and Matthew Kroenig constructed a Parliamentary powers index in an attempt to quantify the different degrees of power among national legislatures. The German Bundestag, the Italian Parliament, and the Mongolian State Great Khural tied for most powerful, while Myanmar's House of Representatives and Somalia's Transitional Federal Assembly (since replaced by the Federal Parliament of Somalia) tied for least powerful. Some political systems follows the principle of legislative supremacy, which holds that the legislature is the supreme branch of government and cannot be bound by other institutions, such as the judicial branch or a written constitution. Such a system renders the legislature more powerful. In parliamentary and semi-presidential systems of government, the executive is responsible to the legislature, which may remove it with a vote of no confidence. On the other hand, according to the separation of powers doctrine, the legislature in a presidential system is considered an independent and coequal branch of government along with both the judiciary and the executive. Nevertheless, many presidential systems provide for the impeachment of the executive for criminal or unconstitutional behaviour. Legislatures will sometimes delegate their legislative power to administrative or executive agencies. Members Legislatures are made up of individual members, known as legislators, who vote on proposed laws. A legislature usually contains a fixed number of legislators; because legislatures usually meet in a specific room filled with seats for the legislators, this is often described as the number of "seats" it contains. For example, a legislature that has 100 "seats" has 100 members. By extension, an electoral district that elects a single legislator can also be described as a "seat", as, for example, in the phrases "safe seat" and "marginal seat". After election, the members may be protected by parliamentary immunity or parliamentary privilege, either for all actions the duration of their entire term, or for just those related to their legislative duties. Chambers A legislature may debate and vote upon bills as a single unit, or it may be composed of multiple separate assemblies, called by various names including legislative chambers, debate chambers, and houses, which debate and vote separately and have distinct powers. A legislature which operates as a single unit is unicameral, one divided into two chambers is bicameral, and one divided into three chambers is tricameral. In bicameral legislatures, one chamber is usually considered the upper house, while the other is considered the lower house. The two types are not rigidly different, but members of upper houses tend to be indirectly elected or appointed rather than directly elected, tend to be allocated by administrative divisions rather than by population, and tend to have longer terms than members of the lower house. In some systems, particularly parliamentary systems, the upper house has less power and tends to have a more advisory role, but in others, particularly federal presidential systems, the upper house has equal or even greater power. In federations, the upper house typically represents the federation's component states. This is also the case with the supranational legislature of the European Union. The upper house may either contain the delegates of state governments – as in the European Union and in Germany and, before 1913, in the United States – or be elected according to a formula that grants equal representation to states with smaller populations, as is the case in Australia and the United States since 1913. Tricameral legislatures are rare; the Massachusetts Governor's Council still exists, but the most recent national example existed in the waning years of White-minority rule in South Africa. Tetracameral legislatures no longer exist, but they were previously used in Scandinavia. The only legislature with a number of chambers bigger than four was the Federal Assembly of Yugoslavia; initially established as a Pentacameral body in 1963, it was turned into a hexacameral body in 1967. Size Legislatures vary widely in their size. Among national legislatures, China's National People's Congress is the largest with 2,980 members, while Vatican City's Pontifical Commission is the smallest with 7. Neither legislature is democratically elected: The Pontifical Commission members are appointed by the Pope and the National People's Congress is indirectly elected within the context of a one-party state. Legislature size is a trade off between efficiency and representation; the smaller the legislature, the more efficiently it can operate, but the larger the legislature, the better it can represent the political diversity of its constituents. Comparative analysis of national legislatures has found that size of a country's lower house tends to be proportional to the cube root of its population; that is, the size of the lower house tends to increase along with population, but much more slowly. See also References Further reading |
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[SOURCE: https://en.wikipedia.org/wiki/Grey_alien#cite_note-Kallen2011-29] | [TOKENS: 2835] |
Contents Grey alien Grey aliens, also referred to as Zeta Reticulans, Roswell Greys, or simply, Greys,[a] are purported extraterrestrial beings. They are frequently featured in claims of close encounter and alien abduction. Greys are typically described as having small, humanoid bodies, smooth, grey skin, disproportionately large, hairless heads, and large, black, almond-shaped eyes. The 1961 Barney and Betty Hill abduction claim was key to the popularization of Grey aliens. Precursor figures have been described in science fiction and similar descriptions appeared in later accounts of the 1947 Roswell UFO incident and early accounts of the 1948 Aztec UFO hoax. The Grey alien is cited an archetypal image of an intelligent non-human creature and extraterrestrial life in general, as well as an iconic trope of popular culture in the age of space exploration. Description Greys are typically depicted as grey-skinned, diminutive humanoid beings that possess reduced forms of, or completely lack, external human body parts such as noses, ears, or sex organs. Their bodies are usually depicted as being elongated, having a small chest, and lacking in muscular definition and visible skeletal structure. Their legs are depicted as being shorter and jointed differently from humans with limbs proportionally different from a human. Greys are depicted as having unusually large heads in proportion to their bodies, and as having no hair, no noticeable outer ears or noses, and small orifices for ears, nostrils, and mouths. In drawings, Greys are almost always shown with very large, opaque, black eyes, without eye whites. They are frequently described as shorter than average adult humans. The association between Grey aliens and Zeta Reticuli originated with the interpretation of a map drawn by Betty Hill by a school-teacher named Marjorie Fish sometime in 1969. Betty Hill, under hypnosis, had claimed to have been shown a map that displayed the aliens' home system and nearby stars. Upon learning of this, Fish attempted to create a model from a drawing produced by Hill, eventually determining that the stars marked as the aliens' home were Zeta Reticuli, a binary star system. History In literature, descriptions of beings similar to Grey aliens predate claims of supposed encounters with them. In 1893, H. G. Wells presented a description of humanity's future appearance in the article "The Man of the Year Million", describing humans as having no mouths, noses, or hair, and with large heads. In 1895, Wells also depicted the Eloi, a successor species to humanity, in similar terms in the novel The Time Machine. Both share many characteristics with future perceptions of Greys. As early as 1917, the occultist Aleister Crowley described a meeting with a "preternatural entity" named Lam that was similar in appearance to a modern Grey. Crowley claimed to have contacted Lam through a process called the "Amalantrah Workings," which he believed allowed humans to contact beings from outer space and across dimensions. Other occultists and ufologists, many of whom have retroactively linked Lam to later Grey encounters, have since described their own visitations from him, with one describing the being as a "cold, computer-like intelligence," and utterly beyond human comprehension. ...the creatures did not resemble any race of humans. They were short, shorter than the average Japanese, and their heads were big and bald, with strong, square foreheads, and very small noses and mouths, and weak chins. What was most extraordinary about them were the eyes—large, dark, gleaming, with a sharp gaze. They wore clothes made of soft grey fabric, and their limbs seemed to be similar to those of humans. In 1933, the Swedish novelist Gustav Sandgren, using the pen name Gabriel Linde, published a science fiction novel called Den okända faran (The Unknown Danger), in which he describes a race of extraterrestrials who wore clothes made of soft grey fabric and were short, with big bald heads, and large, dark, gleaming eyes. The novel, aimed at young readers, included illustrations of the imagined aliens. This description would become the template upon which the popular image of grey aliens is based. The conception remained a niche one until 1965, when newspaper reports of the Betty and Barney Hill abduction made the archetype famous. The alleged abductees, Betty and Barney Hill, claimed that in 1961, humanoid alien beings with greyish skin had abducted them and taken them to a flying saucer. In his 1990 article "Entirely Unpredisposed", Martin Kottmeyer suggested that Barney's memories revealed under hypnosis might have been influenced by an episode of the science-fiction television show The Outer Limits titled "The Bellero Shield", which was broadcast 12 days before Barney's first hypnotic session. The episode featured an extraterrestrial with large eyes, who says, "In all the universes, in all the unities beyond the universes, all who have eyes have eyes that speak." The report from the regression featured a scenario that was in some respects similar to the television show. In part, Kottmeyer wrote: Wraparound eyes are an extreme rarity in science fiction films. I know of only one instance. They appeared on the alien of an episode of an old TV series The Outer Limits entitled "The Bellero Shield." A person familiar with Barney's sketch in "The Interrupted Journey" and the sketch done in collaboration with the artist David Baker will find a "frisson" of "déjà vu" creeping up his spine when seeing this episode. The resemblance is much abetted by an absence of ears, hair, and nose on both aliens. Could it be by chance? Consider this: Barney first described and drew the wraparound eyes during the hypnosis session dated 22 February 1964. "The Bellero Shield" was first broadcast on 10 February 1964. Only twelve days separate the two instances. If the identification is admitted, the commonness of wraparound eyes in the abduction literature falls to cultural forces. — Martin Kottmeyer, Entirely Unpredisposed: The Cultural Background of UFO Reports Carl Sagan echoed Kottmeyer's suspicions in his 1997 book, The Demon Haunted World: Science as a Candle in the Dark, where Invaders from Mars was cited as another potential inspiration. After the Hills' encounter, Greys would go on to become an integral part of ufology and other extraterrestrial-related folklore. This is particularly true in the case of the United States: according to journalist C. D. B. Bryan, 73% of all reported alien encounters in the United States describe Grey aliens, a significantly higher proportion than other countries.: 68 During the early 1980s, Greys were linked to the alleged crash-landing of a flying saucer in Roswell, New Mexico, in 1947. A number of publications contained statements from individuals who claimed to have seen the U.S. military handling a number of unusually proportioned, bald, child-sized beings. These individuals claimed, during and after the incident, that the beings had oversized heads and slanted eyes, but scant other distinguishable facial features. In 1987, novelist Whitley Strieber published the book Communion, which, unlike his previous works, was categorized as non-fiction, and in which he describes a number of close encounters he alleges to have experienced with Greys and other extraterrestrial beings. The book became a New York Times bestseller, and New Line Cinema released a 1989 film adaption that starred Christopher Walken as Strieber. In 1988, Christophe Dechavanne interviewed the French science-fiction writer and ufologist Jimmy Guieu on TF1's Ciel, mon mardi !. Besides mentioning Majestic 12, Guieu described the existence of what he called "the little greys", which later on became better known in French under the name: les Petits-Gris. Guieu later wrote two docudramas, using as a plot the Grey aliens / Majestic-12 conspiracy theory as described by John Lear and Milton William Cooper: the series "E.B.E." (for "Extraterrestrial Biological Entity"): E.B.E.: Alerte rouge (first part) (1990) and E.B.E.: L'entité noire d'Andamooka (second part) (1991).[citation needed] Greys have since become the subject of many conspiracy theories. Many conspiracy theorists believe that Greys represent part of a government-led disinformation or plausible deniability campaign, or that they are a product of government mind-control experiments. During the 1990s, popular culture also began to increasingly link Greys to a number of military-industrial complex and New World Order conspiracy theories. In 1995, filmmaker Ray Santilli claimed to have obtained 22 reels of 16 mm film that depicted the autopsy of a "real" Grey supposedly recovered from the site of the 1947 incident in Roswell. In 2006, though, Santilli announced that the film was not original, but was instead a "reconstruction" created after the original film was found to have degraded. He maintained that a real Grey had been found and autopsied on camera in 1947, and that the footage released to the public contained a percentage of that original footage. Analysis Greys are often involved in alien abduction claims. Among reports of alien encounters, Greys make up about 50% in Australia, 73% in the United States, 48% in continental Europe, and around 12% in the United Kingdom.: 68 These reports include two distinct groups of Greys that differ in height.: 74 Abduction claims are often described as extremely traumatic, similar to an abduction by humans or even a sexual assault in the level of trauma and distress. The emotional impact of perceived abductions can be as great as that of combat, sexual abuse, and other traumatic events. The eyes are often a focus of abduction claims, which often describe a Grey staring into the eyes of an abductee when conducting mental procedures. This staring is claimed to induce hallucinogenic states or directly provoke different emotions. Neurologist Steven Novella proposes that Grey aliens are a byproduct of the human imagination, with the Greys' most distinctive features representing everything that modern humans traditionally link with intelligence. "The aliens, however, do not just appear as humans, they appear like humans with those traits we psychologically associate with intelligence." In 2005, Frederick V. Malmstrom, writing in Skeptic magazine, Volume 11, issue 4, presents his idea that Greys are actually residual memories of early childhood development. Malmstrom reconstructs the face of a Grey through transformation of a mother's face based on our best understanding of early-childhood sensation and perception. Malmstrom's study offers another alternative to the existence of Greys, the intense instinctive response many people experience when presented an image of a Grey, and the act of regression hypnosis and recovered-memory therapy in "recovering" memories of alien abduction experiences, along with their common themes. According to biologist Jack Cohen, the typical image of a Grey, assuming that it would have evolved from a world with different environmental and ecological conditions from Earth, is too physiologically similar to a human to be credible as a representation of an alien. The interdimensional hypothesis, the cryptoterrestrial hypothesis, and the time-traveller hypothesis attempt to provide an alternative explanation to the humanoid anatomy and behavior of these alleged beings. In popular culture Depictions of Grey aliens have gone on to appear in a number of films and television shows, supplanting the previously popular little green men. As early as 1966, for example, the superhero character Ultraman was explicitly based on them, and in 1977 they were featured in Close Encounters of the Third Kind. Greys have also been worked into space opera and other interstellar settings: in Babylon 5, the Greys are referred to as the "Vree", and are depicted as being allies and trade partners of 23rd-century Earth, while in the Stargate franchise they are called the "Asgard" and depicted as ancient astronauts allied with modern-day Earth.[citation needed] South Park refers to them as "visitors". During the 1990s, plotlines wherein Greys were linked to conspiracy theories became common. A well-known example is the Fox television series The X-Files, which first aired in 1993. It combined the quest to find proof of the existence of Grey-like extraterrestrials with a number of UFO conspiracy theory subplots, to form its primary story arc. Other notable examples include the XCOM video game franchise (where they are called "Sectoids"); Dark Skies, first broadcast in 1996, which expanded upon the MJ-12 conspiracy;[citation needed] and American Dad!, which features a Grey-like alien named Roger, whose backstory draws from both the Roswell incident and Area 51 conspiracy theories. The 2011 film Paul tells the story of a Grey named Paul who attributes the Greys' frequent presence in science fiction pop culture to the US government deliberately inserting the stereotypical Grey alien image into mainstream media; this is done so that if humanity came into contact with Paul's species, no immediate shock would occur as to their appearance. Child abduction by Greys is a key plot point in the 2013 film, Dark Skies. Greys appear in Syfy's 2021 science fiction dramedy series Resident Alien. The Greys appear as the main antagonistic faction in the 2023 independent game Greyhill Incident. See also Notes References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Python_(programming_language)#cite_note-AutoNT-7-35] | [TOKENS: 4314] |
Contents Python (programming language) Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically type-checked and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming. Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language. Python 3.0, released in 2008, was a major revision and not completely backward-compatible with earlier versions. Beginning with Python 3.5, capabilities and keywords for typing were added to the language, allowing optional static typing. As of 2026[update], the Python Software Foundation supports Python 3.10, 3.11, 3.12, 3.13, and 3.14, following the project's annual release cycle and five-year support policy. Python 3.15 is currently in the alpha development phase, and the stable release is expected to come out in October 2026. Earlier versions in the 3.x series have reached end-of-life and no longer receive security updates. Python has gained widespread use in the machine learning community. It is widely taught as an introductory programming language. Since 2003, Python has consistently ranked in the top ten of the most popular programming languages in the TIOBE Programming Community Index, which ranks based on searches in 24 platforms. History Python was conceived in the late 1980s by Guido van Rossum at Centrum Wiskunde & Informatica (CWI) in the Netherlands. It was designed as a successor to the ABC programming language, which was inspired by SETL, capable of exception handling and interfacing with the Amoeba operating system. Python implementation began in December 1989. Van Rossum first released it in 1991 as Python 0.9.0. Van Rossum assumed sole responsibility for the project, as the lead developer, until 12 July 2018, when he announced his "permanent vacation" from responsibilities as Python's "benevolent dictator for life" (BDFL); this title was bestowed on him by the Python community to reflect his long-term commitment as the project's chief decision-maker. (He has since come out of retirement and is self-titled "BDFL-emeritus".) In January 2019, active Python core developers elected a five-member Steering Council to lead the project. The name Python derives from the British comedy series Monty Python's Flying Circus. (See § Naming.) Python 2.0 was released on 16 October 2000, featuring many new features such as list comprehensions, cycle-detecting garbage collection, reference counting, and Unicode support. Python 2.7's end-of-life was initially set for 2015, and then postponed to 2020 out of concern that a large body of existing code could not easily be forward-ported to Python 3. It no longer receives security patches or updates. While Python 2.7 and older versions are officially unsupported, a different unofficial Python implementation, PyPy, continues to support Python 2, i.e., "2.7.18+" (plus 3.11), with the plus signifying (at least some) "backported security updates". Python 3.0 was released on 3 December 2008, and was a major revision and not completely backward-compatible with earlier versions, with some new semantics and changed syntax. Python 2.7.18, released in 2020, was the last release of Python 2. Several releases in the Python 3.x series have added new syntax to the language, and made a few (considered very minor) backward-incompatible changes. As of January 2026[update], Python 3.14.3 is the latest stable release. All older 3.x versions had a security update down to Python 3.9.24 then again with 3.9.25, the final version in 3.9 series. Python 3.10 is, since November 2025, the oldest supported branch. Python 3.15 has an alpha released, and Android has an official downloadable executable available for Python 3.14. Releases receive two years of full support followed by three years of security support. Design philosophy and features Python is a multi-paradigm programming language. Object-oriented programming and structured programming are fully supported, and many of their features support functional programming and aspect-oriented programming – including metaprogramming and metaobjects. Many other paradigms are supported via extensions, including design by contract and logic programming. Python is often referred to as a 'glue language' because it is purposely designed to be able to integrate components written in other languages. Python uses dynamic typing and a combination of reference counting and a cycle-detecting garbage collector for memory management. It uses dynamic name resolution (late binding), which binds method and variable names during program execution. Python's design offers some support for functional programming in the "Lisp tradition". It has filter, map, and reduce functions; list comprehensions, dictionaries, sets, and generator expressions. The standard library has two modules (itertools and functools) that implement functional tools borrowed from Haskell and Standard ML. Python's core philosophy is summarized in the Zen of Python (PEP 20) written by Tim Peters, which includes aphorisms such as these: However, Python has received criticism for violating these principles and adding unnecessary language bloat. Responses to these criticisms note that the Zen of Python is a guideline rather than a rule. The addition of some new features had been controversial: Guido van Rossum resigned as Benevolent Dictator for Life after conflict about adding the assignment expression operator in Python 3.8. Nevertheless, rather than building all functionality into its core, Python was designed to be highly extensible via modules. This compact modularity has made it particularly popular as a means of adding programmable interfaces to existing applications. Van Rossum's vision of a small core language with a large standard library and easily extensible interpreter stemmed from his frustrations with ABC, which represented the opposite approach. Python claims to strive for a simpler, less-cluttered syntax and grammar, while giving developers a choice in their coding methodology. Python lacks do .. while loops, which Rossum considered harmful. In contrast to Perl's motto "there is more than one way to do it", Python advocates an approach where "there should be one – and preferably only one – obvious way to do it". In practice, however, Python provides many ways to achieve a given goal. There are at least three ways to format a string literal, with no certainty as to which one a programmer should use. Alex Martelli is a Fellow at the Python Software Foundation and Python book author; he wrote that "To describe something as 'clever' is not considered a compliment in the Python culture." Python's developers typically prioritize readability over performance. For example, they reject patches to non-critical parts of the CPython reference implementation that would offer increases in speed that do not justify the cost of clarity and readability.[failed verification] Execution speed can be improved by moving speed-critical functions to extension modules written in languages such as C, or by using a just-in-time compiler like PyPy. Also, it is possible to transpile to other languages. However, this approach either fails to achieve the expected speed-up, since Python is a very dynamic language, or only a restricted subset of Python is compiled (with potential minor semantic changes). Python is meant to be a fun language to use. This goal is reflected in the name – a tribute to the British comedy group Monty Python – and in playful approaches to some tutorials and reference materials. For instance, some code examples use the terms "spam" and "eggs" (in reference to a Monty Python sketch), rather than the typical terms "foo" and "bar". A common neologism in the Python community is pythonic, which has a broad range of meanings related to program style: Pythonic code may use Python idioms well; be natural or show fluency in the language; or conform with Python's minimalist philosophy and emphasis on readability. Syntax and semantics Python is meant to be an easily readable language. Its formatting is visually uncluttered and often uses English keywords where other languages use punctuation. Unlike many other languages, it does not use curly brackets to delimit blocks, and semicolons after statements are allowed but rarely used. It has fewer syntactic exceptions and special cases than C or Pascal. Python uses whitespace indentation, rather than curly brackets or keywords, to delimit blocks. An increase in indentation comes after certain statements; a decrease in indentation signifies the end of the current block. Thus, the program's visual structure accurately represents its semantic structure. This feature is sometimes termed the off-side rule. Some other languages use indentation this way; but in most, indentation has no semantic meaning. The recommended indent size is four spaces. Python's statements include the following: The assignment statement (=) binds a name as a reference to a separate, dynamically allocated object. Variables may subsequently be rebound at any time to any object. In Python, a variable name is a generic reference holder without a fixed data type; however, it always refers to some object with a type. This is called dynamic typing—in contrast to statically-typed languages, where each variable may contain only a value of a certain type. Python does not support tail call optimization or first-class continuations; according to Van Rossum, the language never will. However, better support for coroutine-like functionality is provided by extending Python's generators. Before 2.5, generators were lazy iterators; data was passed unidirectionally out of the generator. From Python 2.5 on, it is possible to pass data back into a generator function; and from version 3.3, data can be passed through multiple stack levels. Python's expressions include the following: In Python, a distinction between expressions and statements is rigidly enforced, in contrast to languages such as Common Lisp, Scheme, or Ruby. This distinction leads to duplicating some functionality, for example: A statement cannot be part of an expression; because of this restriction, expressions such as list and dict comprehensions (and lambda expressions) cannot contain statements. As a particular case, an assignment statement such as a = 1 cannot be part of the conditional expression of a conditional statement. Python uses duck typing, and it has typed objects but untyped variable names. Type constraints are not checked at definition time; rather, operations on an object may fail at usage time, indicating that the object is not of an appropriate type. Despite being dynamically typed, Python is strongly typed, forbidding operations that are poorly defined (e.g., adding a number and a string) rather than quietly attempting to interpret them. Python allows programmers to define their own types using classes, most often for object-oriented programming. New instances of classes are constructed by calling the class, for example, SpamClass() or EggsClass()); the classes are instances of the metaclass type (which is an instance of itself), thereby allowing metaprogramming and reflection. Before version 3.0, Python had two kinds of classes, both using the same syntax: old-style and new-style. Current Python versions support the semantics of only the new style. Python supports optional type annotations. These annotations are not enforced by the language, but may be used by external tools such as mypy to catch errors. Python includes a module typing including several type names for type annotations. Also, mypy supports a Python compiler called mypyc, which leverages type annotations for optimization. 1.33333 frozenset() Python includes conventional symbols for arithmetic operators (+, -, *, /), the floor-division operator //, and the modulo operator %. (With the modulo operator, a remainder can be negative, e.g., 4 % -3 == -2.) Also, Python offers the ** symbol for exponentiation, e.g. 5**3 == 125 and 9**0.5 == 3.0. Also, it offers the matrix‑multiplication operator @ . These operators work as in traditional mathematics; with the same precedence rules, the infix operators + and - can also be unary, to represent positive and negative numbers respectively. Division between integers produces floating-point results. The behavior of division has changed significantly over time: In Python terms, the / operator represents true division (or simply division), while the // operator represents floor division. Before version 3.0, the / operator represents classic division. Rounding towards negative infinity, though a different method than in most languages, adds consistency to Python. For instance, this rounding implies that the equation (a + b)//b == a//b + 1 is always true. Also, the rounding implies that the equation b*(a//b) + a%b == a is valid for both positive and negative values of a. As expected, the result of a%b lies in the half-open interval [0, b), where b is a positive integer; however, maintaining the validity of the equation requires that the result must lie in the interval (b, 0] when b is negative. Python provides a round function for rounding a float to the nearest integer. For tie-breaking, Python 3 uses the round to even method: round(1.5) and round(2.5) both produce 2. Python versions before 3 used the round-away-from-zero method: round(0.5) is 1.0, and round(-0.5) is −1.0. Python allows Boolean expressions that contain multiple equality relations to be consistent with general usage in mathematics. For example, the expression a < b < c tests whether a is less than b and b is less than c. C-derived languages interpret this expression differently: in C, the expression would first evaluate a < b, resulting in 0 or 1, and that result would then be compared with c. Python uses arbitrary-precision arithmetic for all integer operations. The Decimal type/class in the decimal module provides decimal floating-point numbers to a pre-defined arbitrary precision with several rounding modes. The Fraction class in the fractions module provides arbitrary precision for rational numbers. Due to Python's extensive mathematics library and the third-party library NumPy, the language is frequently used for scientific scripting in tasks such as numerical data processing and manipulation. Functions are created in Python by using the def keyword. A function is defined similarly to how it is called, by first providing the function name and then the required parameters. Here is an example of a function that prints its inputs: To assign a default value to a function parameter in case no actual value is provided at run time, variable-definition syntax can be used inside the function header. Code examples "Hello, World!" program: Program to calculate the factorial of a non-negative integer: Libraries Python's large standard library is commonly cited as one of its greatest strengths. For Internet-facing applications, many standard formats and protocols such as MIME and HTTP are supported. The language includes modules for creating graphical user interfaces, connecting to relational databases, generating pseudorandom numbers, arithmetic with arbitrary-precision decimals, manipulating regular expressions, and unit testing. Some parts of the standard library are covered by specifications—for example, the Web Server Gateway Interface (WSGI) implementation wsgiref follows PEP 333—but most parts are specified by their code, internal documentation, and test suites. However, because most of the standard library is cross-platform Python code, only a few modules must be altered or rewritten for variant implementations. As of 13 March 2025,[update] the Python Package Index (PyPI), the official repository for third-party Python software, contains over 614,339 packages. Development environments Most[which?] Python implementations (including CPython) include a read–eval–print loop (REPL); this permits the environment to function as a command line interpreter, with which users enter statements sequentially and receive results immediately. Also, CPython is bundled with an integrated development environment (IDE) called IDLE, which is oriented toward beginners.[citation needed] Other shells, including IDLE and IPython, add additional capabilities such as improved auto-completion, session-state retention, and syntax highlighting. Standard desktop IDEs include PyCharm, Spyder, and Visual Studio Code; there are web browser-based IDEs, such as the following environments: Implementations CPython is the reference implementation of Python. This implementation is written in C, meeting the C11 standard since version 3.11. Older versions use the C89 standard with several select C99 features, but third-party extensions are not limited to older C versions—e.g., they can be implemented using C11 or C++. CPython compiles Python programs into an intermediate bytecode, which is then executed by a virtual machine. CPython is distributed with a large standard library written in a combination of C and native Python. CPython is available for many platforms, including Windows and most modern Unix-like systems, including macOS (and Apple M1 Macs, since Python 3.9.1, using an experimental installer). Starting with Python 3.9, the Python installer intentionally fails to install on Windows 7 and 8; Windows XP was supported until Python 3.5, with unofficial support for VMS. Platform portability was one of Python's earliest priorities. During development of Python 1 and 2, even OS/2 and Solaris were supported; since that time, support has been dropped for many platforms. All current Python versions (since 3.7) support only operating systems that feature multithreading, by now supporting not nearly as many operating systems (dropping many outdated) than in the past. All alternative implementations have at least slightly different semantics. For example, an alternative may include unordered dictionaries, in contrast to other current Python versions. As another example in the larger Python ecosystem, PyPy does not support the full C Python API. Creating an executable with Python often is done by bundling an entire Python interpreter into the executable, which causes binary sizes to be massive for small programs, yet there exist implementations that are capable of truly compiling Python. Alternative implementations include the following: Stackless Python is a significant fork of CPython that implements microthreads. This implementation uses the call stack differently, thus allowing massively concurrent programs. PyPy also offers a stackless version. Just-in-time Python compilers have been developed, but are now unsupported: There are several compilers/transpilers to high-level object languages; the source language is unrestricted Python, a subset of Python, or a language similar to Python: There are also specialized compilers: Some older projects existed, as well as compilers not designed for use with Python 3.x and related syntax: A performance comparison among various Python implementations, using a non-numerical (combinatorial) workload, was presented at EuroSciPy '13. In addition, Python's performance relative to other programming languages is benchmarked by The Computer Language Benchmarks Game. There are several approaches to optimizing Python performance, despite the inherent slowness of an interpreted language. These approaches include the following strategies or tools: Language Development Python's development is conducted mostly through the Python Enhancement Proposal (PEP) process; this process is the primary mechanism for proposing major new features, collecting community input on issues, and documenting Python design decisions. Python coding style is covered in PEP 8. Outstanding PEPs are reviewed and commented on by the Python community and the steering council. Enhancement of the language corresponds with development of the CPython reference implementation. The mailing list python-dev is the primary forum for the language's development. Specific issues were originally discussed in the Roundup bug tracker hosted by the foundation. In 2022, all issues and discussions were migrated to GitHub. Development originally took place on a self-hosted source-code repository running Mercurial, until Python moved to GitHub in January 2017. CPython's public releases have three types, distinguished by which part of the version number is incremented: Many alpha, beta, and release-candidates are also released as previews and for testing before final releases. Although there is a rough schedule for releases, they are often delayed if the code is not ready yet. Python's development team monitors the state of the code by running a large unit test suite during development. The major academic conference on Python is PyCon. Also, there are special Python mentoring programs, such as PyLadies. Naming Python's name is inspired by the British comedy group Monty Python, whom Python creator Guido van Rossum enjoyed while developing the language. Monty Python references appear frequently in Python code and culture; for example, the metasyntactic variables often used in Python literature are spam and eggs, rather than the traditional foo and bar. Also, the official Python documentation contains various references to Monty Python routines. Python users are sometimes referred to as "Pythonistas". Languages influenced by Python See also Notes References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Directed_graph] | [TOKENS: 972] |
Contents Directed graph In mathematics, and more specifically in graph theory, a directed graph (or digraph) is a graph that is made up of a set of vertices connected by directed edges, often called arcs. Definition In formal terms, a directed graph is an ordered pair G = (V, A) where It differs from an ordinary or undirected graph, in that the latter is defined in terms of unordered pairs of vertices, which are usually called edges, links or lines. The aforementioned definition does not allow a directed graph to have multiple arrows with the same source and target nodes, but some authors consider a broader definition that allows directed graphs to have such multiple arcs (namely, they allow the arc set to be a multiset). Sometimes these entities are called directed multigraphs (or multidigraphs). On the other hand, the aforementioned definition allows a directed graph to have loops (that is, arcs that directly connect nodes with themselves), but some authors consider a narrower definition that does not allow directed graphs to have loops. Directed graphs without loops may be called simple directed graphs, while directed graphs with loops may be called loop-digraphs (see section Types of directed graph). Types of directed graphs Basic terminology An arc (x, y) is considered to be directed from x to y; y is called the head and x is called the tail of the arc; y is said to be a direct successor of x and x is said to be a direct predecessor of y. If a path leads from x to y, then y is said to be a successor of x and reachable from x, and x is said to be a predecessor of y. The arc (y, x) is called the reversed arc of (x, y). The adjacency matrix of a multidigraph with loops is the integer-valued matrix with rows and columns corresponding to the vertices, where a nondiagonal entry aij is the number of arcs from vertex i to vertex j, and the diagonal entry aii is the number of loops at vertex i. The adjacency matrix of a directed graph is a logical matrix, and is unique up to permutation of rows and columns. Another matrix representation for a directed graph is its incidence matrix. See direction for more definitions. Indegree and outdegree For a vertex, the number of head ends adjacent to a vertex is called the indegree of the vertex and the number of tail ends adjacent to a vertex is its outdegree (called branching factor in trees). Let G = (V, E) and v ∈ V. The indegree of v is denoted deg−(v) and its outdegree is denoted deg+(v). A vertex with deg−(v) = 0 is called a source, as it is the origin of each of its outgoing arcs. Similarly, a vertex with deg+(v) = 0 is called a sink, since it is the end of each of its incoming arcs. The degree sum formula states that, for a directed graph, If for every vertex v ∈ V, deg+(v) = deg−(v), the graph is called a balanced directed graph. Degree sequence The degree sequence of a directed graph is the list of its indegree and outdegree pairs; for the above example we have degree sequence ((2, 0), (2, 2), (0, 2), (1, 1)). The degree sequence is a directed graph invariant so isomorphic directed graphs have the same degree sequence. However, the degree sequence does not, in general, uniquely identify a directed graph; in some cases, non-isomorphic digraphs have the same degree sequence. The directed graph realization problem is the problem of finding a directed graph with the degree sequence a given sequence of positive integer pairs. (Trailing pairs of zeros may be ignored since they are trivially realized by adding an appropriate number of isolated vertices to the directed graph.) A sequence which is the degree sequence of some directed graph, i.e. for which the directed graph realization problem has a solution, is called a directed graphic or directed graphical sequence. This problem can either be solved by the Kleitman–Wang algorithm or by the Fulkerson–Chen–Anstee theorem. Directed graph connectivity A directed graph is weakly connected (or just connected) if the undirected underlying graph obtained by replacing all directed edges of the graph with undirected edges is a connected graph. A directed graph is strongly connected or strong if it contains a directed path from x to y (and from y to x) for every pair of vertices (x, y). The strong components are the maximal strongly connected subgraphs. A connected rooted graph (or flow graph) is one where there exists a directed path to every vertex from a distinguished root vertex. See also Notes References External links |
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[SOURCE: https://github.com/resources/articles?topic=ai] | [TOKENS: 573] |
Navigation Menu Search code, repositories, users, issues, pull requests... Provide feedback We read every piece of feedback, and take your input very seriously. Saved searches Use saved searches to filter your results more quickly To see all available qualifiers, see our documentation. GitHub Articles Filters (1) Topic Generative AI creates new content—text, code, images, audio, and video—from existing data. Generative AI creates new content—text, code, images, audio, and video—from existing data. Unsupervised learning finds patterns in unlabeled data, making sense of complex datasets. Unsupervised learning finds patterns in unlabeled data, making sense of complex datasets. Open source AI offers more control, clarity, and room to build the way you want. Open source AI offers more control, clarity, and room to build the way you want. Turn ideas into code faster with plain language prompts and agentic AI support. Turn ideas into code faster with plain language prompts and agentic AI support. AI often struggles with knowledge gaps and factual errors. Learn how retrieval-augmented generation (RAG) helps solve this. AI often struggles with knowledge gaps and factual errors. Learn how retrieval-augmented generation (RAG) helps solve this. Prompt engineering is the practice of crafting effective instructions that guide AI models to produce accurate, useful results. Prompt engineering is the practice of crafting effective instructions that guide AI models to produce accurate, useful results. AI for IT operations (AIOps) uses AI to help IT teams reduce downtime and scale operations. AI for IT operations (AIOps) uses AI to help IT teams reduce downtime and scale operations. Discover what neural networks are and why they’re critical to developing intelligent systems. Discover what neural networks are and why they’re critical to developing intelligent systems. AI code generation uses machine learning models to write code from input that describes what the code should do, and the models provide context-based code suggestions along the way. AI generated code isn’t always perfect, but it often gives developers a suitable starting point for writing code quickly and efficiently. AI code generation uses machine learning models to write code from input that describes what the code should do, and the models provide context-based code suggestions along the way. AI generated code isn’t always perfect, but it often gives developers a suitable starting point for writing code quickly and efficiently. Discover how agentic AI helps software development teams increase productivity and focus on more strategic tasks. Discover how agentic AI helps software development teams increase productivity and focus on more strategic tasks. Learn how generative AI models help businesses succeed. Learn how generative AI models help businesses succeed. Learn how AI models work and how they can help your org. Learn how AI models work and how they can help your org. Site-wide Links Get tips, technical guides, and best practices. Twice a month. |
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[SOURCE: https://en.wikipedia.org/wiki/Virtua_Fighter_(video_game)] | [TOKENS: 4413] |
Contents Virtua Fighter (video game) Virtua Fighter[a] is a 1993 fighting game developed and published by Sega for arcades. It was developed for the Sega Model 1 arcade platform by AM2, a development group within Sega headed by Yu Suzuki. An early prototype version was location tested in Japan by August 1993, before the complete game was released worldwide in December 1993. It was the first arcade fighting game to feature fully 3D polygon graphics. The game was ported to Sega Saturn as a global launch title in 1994 and 1995, and also received a port to the Sega 32X. The game was critically acclaimed and a major hit, becoming one of Sega's best-selling arcade games of all time with more than 40,000 arcade units sold while the Saturn versions sold over 1 million copies. Virtua Fighter was highly regarded for its in-depth 3D fighting engine and real-world fighting techniques, and has been revolutionary and highly influential in the evolution of the genre and video games in general. Its success led to the Virtua Fighter series, with its sequel Virtua Fighter 2 released in 1994. In 1995, an update titled Virtua Fighter Remix was developed and released by AM1, featuring drastic graphical improvements. This improved version was quickly ported to the Saturn console and later received a port to Windows. The game's remake, Virtua Fighter 10th Anniversary, was released for the PlayStation 2 in 2003 as a standalone title in Japan and as a bonus in Virtua Fighter 4: Evolution in North America. Gameplay The Virtua label indicates that the onscreen action takes place in a 3D environment; however, movement is restricted to 2D. The graphics were made using wireframe and flat-shaded quad polygons. The game retains the fighting game staple of having multiple characters, each with their own distinctive moves. In the game's single-player mode, the player faces all eight characters (including a duplicate of the chosen character) in a pre-determined order, followed by a fight with the game's boss, Dural. Each fight is a best-of-three match, and the player has three ways of winning: knocking out the opponent, forcing them out of the ring, or having more health left when time runs out. Unlike other fighting games of the early 1990s (such as Street Fighter II or Mortal Kombat), the game relies on a control stick and only three buttons, punch, kick and guard (block), although different situations and button combinations led to a vast variety of moves for each character. Plot An Arab fighter named Majido "Siba" Abdul was planned, and his character model appeared on some Virtua Fighter arcade cabinets (though, in some cases, Akira's name was placed under his portrait). Siba was originally to be the protagonist of the franchise. He was ultimately dropped, but later appeared in Fighters Megamix. Two other characters were also discovered. One was an early design of Akira Yuki, under an early name Takeru Ryushoji, who was shirtless and wore pants and shoes. The other was a military man named Jeffery "Jeff" Buckman.[additional citation(s) needed] Other fighters in the game that were planned to appear were the Koskol brothers Rekka (the eldest) Score (the middle) and Aeon (the youngest), these 6 fighters were part of an organization known as the "Red Scorpions", but was later scrapped.[citation needed] Once in the Shōwa period, the defunct Japanese army intended to approach Puyi, the last Emperor of the Qing Dynasty in their effort to take advantages. However, they were defeated by the Imperial guards who used the martial art called Hakkyoku-ken. During World War II, the Japanese army research the mysteries of Hakkyoku-ken to create supersoldiers, developing the ultimate martial art. Approximately half a century has passed since then, the ultimate World Fighting Tournament is about to start, and all kinds of fighters from around the world engage to determine the world's best. Behind the Tournament, however, there exists an intrigue designed by a sinister syndicate. Development and release The game's development began in 1992, following the development of Virtua Racing. Virtua Fighter was developed to run on Sega Model 1 arcade hardware, developed internally at Sega. According to Sega of Japan's publicity manager, Kurokawa, "We deliberately didn't publicize all the [fighting] moves at the same time but instead revealed them to gamers one at a time by means of the Japanese videogame press." Virtua Fighter also used 3D motion capture technology. Before Virtua Fighter, Sega AM3 simulated 3D using a creative method of sprite scaling on the 1993 arcade fighting game Dark Edge. According to Suzuki, an issue during the game's development was performing fast division calculations for 3D operations. The only applications he was aware of performing fast enough divisions at the time were nuclear reactors and space rockets. The team "were working away with craftsmanship equivalent to inscribing 100 words on a single grain of rice" to achieve fast 3D division operations, according to Suzuki. An early prototype version of the arcade game featured an Arab fighter called Siba. This early version did not have Akira Yuki, who was added later in development as a replacement for Siba, with Akira becoming the game's protagonist. This early prototype version was location tested in Japan and then demonstrated at the Amusement Machine Show (AM Show) in August 1993. Virtua Fighter was a launch game for the Sega Saturn, and served as the pack-in launch game in North America. Its Sega 32X version was developed by the same team responsible for the Genesis port of Virtua Racing. Virtua Fighter Remix was an update of the original Virtua Fighter with higher-polygon models, texture mapping, and some gameplay changes. It was given free to all registered Saturn owners in the United States via mail. It had an arcade release on the ST-V (an arcade platform based on the Sega Saturn) and later ported to Microsoft Windows as Virtua Fighter PC. In Japan, Game Machine listed it on their August 1, 1995, issue as being the twenty-first most-successful arcade game of the month. With the 2003 PlayStation 2 release of Virtua Fighter 4: Evolution arriving in time for the series' tenth anniversary, a remake of Virtua Fighter, Virtua Fighter 10th Anniversary, was released on the PlayStation 2. While the music, stages and low-polygon visual style were retained from the first game, the character roster, animations, mechanics and movesets were taken from Evolution. In the previous PS2 release of Virtua Fighter 4, a button code would make the player's character look like a Virtua Fighter model. In Japan, the game was included as part of a box set with a book called Virtua Fighter 10th Anniversary: Memory of a Decade and a DVD. The box set was released in November 2003 and was published by Enterbrain. In North America, the game was included in the home version of Virtua Fighter 4: Evolution, and in Europe it was only available as a promotional item; it was not sold at retail. Reception Sega began location testing an early prototype version in Japan prior to the game's demonstration at the Amusement Machine Show (AM Show) in August 1993. Sega reported it to be their highest-earning location test performance of all time, with each test machine earning a daily average of ¥60,000 or $600 (equivalent to $1,337 in 2025). At the 1993 AM Show, it was rated the "hit of the show" by many visitors. Upon the game's release in Japan, Game Machine listed Virtua Fighter as the country's most popular upright/cockpit arcade game of December 1993. It went on to become Japan's highest-grossing arcade game of 1994, and one of the country's highest-grossing arcade games of all time. According to Next Generation magazine in 1995, Virtua Fighter was "the biggest game in Japan since Super Mario World." In North America, RePlay reported Virtua Fighter to be the sixth most popular upright arcade game of February 1994; it went on to be one of America's top five highest-grossing arcade games of 1994. In the United Kingdom, it was the second top-grossing arcade game in London during early 1994 (below Ridge Racer), and went on to be one of the most popular coin-ops of the year. Virtua Fighter sold more than 40,000 arcade units worldwide by 1996, with each unit costing between $15,000 (equivalent to $33,000 in 2025) and £14,000 / $21,000 (equivalent to $47,000 in 2025). Virtua Fighter and Virtua Fighter 2 (1994) became Sega's best-selling arcade games of all time, surpassing their previous record holder Out Run (1986). Following its demonstration at the 1993 AM Show, Virtua Fighter received a positive industry reception. RePlay magazine called "the adaptation of 3-D polygon graphics to video fighting games" a "sensational development that could define and revitalize this already-hot category." California Games CEO Pat Schroeder said Virtua Fighter "was by far the dawn of a new era of games" with praise for the "computerized 3-D graphics with effects that are unreal" and how it "shows the fighting action" from different angles. Edge magazine called Virtua Fighter "a tantalising glimpse into the future of fighting games employing the same ground-breaking CG computer graphics system as Virtua Racing." While criticizing the appearance of the "excessively blocky polygonised people," Edge said "the 3D scrolling, animation and movement are all silky-smooth and very realistic" and that "the fluid animation and imaginative camera angles quickly won the audience over." Electronic Gaming Monthly hailed Virtua Fighter as a demonstration of "just how far video games have come in the last eight years." EGM made particular note of the advanced graphics, how the camera moves along different axes depending on the fighters' location, the use of multiple viewpoints in the instant replay, the high quality of the gameplay, and the smoothness and realism of the animation. In January 1994, Rik Skews of Computer and Video Games magazine, after playing for 1 hour, initially praised the "brilliant 64-bit" 3D graphics, animation and camera work but compared the gameplay unfavorably to Street Fighter II. Computer and Video Games was later more positive towards the gameplay, stating in December 1994 that the game "combined cutting edge arcade technology with motion capture techniques and some excellent gameplay design." Next Generation said in 1995 that it epitomized Yu Suzuki's "skill of finding the perfect blend of state-of-the-art technology with solid gameplay" in "the cut-throat world" of arcades. The console port of Virtua Fighter, which was very close to the arcade game, sold at a nearly 1:1 ratio with the Saturn hardware during the Japanese launch. The Future Publishing magazine Ultimate Future Games called Virtua Fighter the "game that killed" the 16-bit machines. The Saturn version sold 630,000 units in Japan, while Remix sold a further 437,036 units there in 1995, for a combined total of 1,067,036 units sold for the Saturn in Japan. On release of the Saturn version, Sega Saturn Tsūshin scored the game a 38 out of 40. Famicom Tsūshin's four critics would each score the same version a nine out of ten rating in December 1994. Computer and Video Games reviewed a Japanese import in December 1994, stating "the last machine to generate so much interest in this office was the arrival of" the Super Famicom with Super Mario World. Steve James praised the "superlative" moves, "amazingly crisp" sound samples, and "totally realistic" action; Mark Patterson, while criticizing the high UK import price of £70–80 ($107–122), concluded with "credit to Sega for producing an excellent machine, and even more to AM2 for its near-perfect conversion of this fantastic game." In a review of the Japanese release, GamePro praised the retention of the fighters, moves, varying camera angles, and controls of the arcade version, as well as the improved voice and sound effects and home version options, and concluded it to be "one of the best games ever bundled with a system". Their later review of the North American release was similarly laudatory, but remarked that Tekken and Battle Arena Toshinden for the soon-to-launch PlayStation were even better. Next Generation, which also reviewed the game prior to the Saturn's USA launch, disagreed, contending that "What Virtua Fighter lacks in [Battle Arena] Tohshinden's immediate graphical punch, it makes up for in grinding longevity." They particularly praised the game's depth and realism, and summarized that "The Saturn Virtua Fighter is, to all intents and purposes, the coin-op game brought home. And away from the arcade, under the harsh light of unhurried examination, its merits grow." Maximum gave it five out of five stars, calling it "a stunningly close conversion that is quite possibly the best game available for the machine." They remarked that the innovations such as the 3D motion capture remained impressive, as well as the depth and variety of the character's gameplay application: "every fighter has almost limitless scope for coming up with all-new attacks." They also praised the "very clever mixture of superbly exaggerated sound effects coupled with a tangible, realistic impact for every blow." Electronic Gaming Monthly were more subdued in their reaction, but two of their four reviewers commented that it was nearly identical to the arcade version. They scored it 31.5 out of 40 (average 7.875 out of 10). Edge rated the Saturn version 9/10, stating: "Saturn Virtua Fighter has all the pulling power of the arcade version, including the swooping, gliding game camera, the stylish polygon characters, the totally convincing animation and the compulsive gameplay ... [The graphics] were impressive enough in the original, but on the Saturn, under the kind of intense scrutiny you can never give a game in the arcades, they emerge as simply astounding ... It's arguably the first true 'next generation' console game, fusing the best aspects of combat gameplay with groundbreaking animation and gorgeous sound". Sega Saturn Magazine gave Virtua Fighter Remix five out of five stars, saying that it fixed the glitches and graphics of the original game while maintaining the already excellent gameplay. Electronic Gaming Monthly scored Remix 29 out of 40 (average 7.25 out of 10). The reviewers praised all the game's improvements, but most of them concluded that it was still not worth buying for players who already owned the original game. Maximum likewise praised the quality of the game and its low price tag, but felt it was not worth buying, with the release of the even better Saturn conversion of Virtua Fighter 2 less than a month away. They scored it four out of five stars. The staff of Next Generation gave it five out of five stars, applauding the graphical improvements and glitch fixes. They commented: "Perhaps never in videogame history has a problem such as Virtua Fighter been so quickly and thoroughly corrected. Virtua Fighter Remix contains all the great gameplay of the original without any of the weak spots." Scary Larry of GamePro gave the game a highly positive review for its graphical enhancements and retention of all the excellent gameplay of the original Saturn version. GamePro also ran two reader-submitted reviews for the game; King Kane argued that the graphical and audio improvements make the game worth trying even for those who are not fans of Virtua Fighter, while Tricky Ricky argued that though the game is an impressive upgrade, the lack of changes to the gameplay make its appeal quickly fade. Famicom Tsūshin scored Virtua Fighter Remix a 35 out of 40, and the Sega 32X version of the game a 30 out of 40. Next Generation reviewed the arcade version of the game, and stated that "The drawback of all Titan games, including Remix, is that the technology isn't as advanced, fast, or powerful as Model 2B [...] and these games are really like playing fast Saturn games in the arcade." Electronic Gaming Monthly scored the 32X version 30.5 out of 40 (average 7.625 out of 10), calling it an excellent conversion given the system it's on, but dated next to the graphically superior Saturn version and especially Virtua Fighter Remix, both of which had already been released. GamePro also noted that the 32X version suffers from more slowdown and fewer polygons than the Saturn version, as well as "tinny sound quality", but praised the additional options not included in the Saturn version and rated it as an overall strong port. A critic for Next Generation similarly said that the 32X version is not as impressive looking as the Saturn version but has more options and fewer glitches, making it an overall excellent port. He argued that the game was not worth buying a 32X for, since the system was not powerful enough to handle ports of Virtua Fighter Remix or Virtua Fighter 2 (which was soon to be released for the Saturn), but that it was an essential purchase for those who already own a 32X. In 1995, Flux rated the arcade version 16th in its Top 100 Video Games. At the time, they called Virtua Fighter: "The most satisfying fighter in existence." In 1996, Computer Gaming World declared Virtua Fighter PC the 121st-best computer game ever released. In 1996, GamesMaster ranked Virtua Fighter eighth on their "The GamesMaster Saturn Top 10." Legacy and impact Virtua Fighter dispensed with sprite-based graphics, replacing them with flat-shaded polygons rendered in real-time, by the Model 1's 3D-rendering hardware, allowing for effects and technologies that were impossible in sprite-based fighters, such as characters that could move in three dimensions, and a dynamic camera that could zoom, pan and swoop dramatically around the arena. It has been credited with both introducing and popularizing the use of polygon-based 3D graphics in fighting games. Next Generation said in 1995 that Virtua Fighter was "arguably the most significant game" of the 1990s. 1UP listed it as one of the 50 most important games of all time. They credited Virtua Fighter for creating the 3D fighting game genre, and more generally, demonstrating the potential of 3D polygon human characters (as the first to implement them in a useful way), showing the potential of realistic gameplay (introducing a character physics system and realistic character animations), and introducing fighting game concepts such as the ring-out and the block button. At a time when fighting games were becoming increasingly focused on violence and shock value, the popularity of Virtua Fighter demonstrated that fighting games focused on gameplay were still commercially viable. Nintendo's Shigeru Miyamoto said that for several years after Virtua Fighter was released he was disinterested in making fighting games because he felt that "I was beaten to the punch when Virtua Fighter came out", and that any fighting game he produced would have been perceived as an attempt to copy Virtua Fighter. Game designer Yasuyuki Oda remarked that he was impressed by this video game while working for SNK. In particular, Virtua Fighter garnered praise for its simple three-button control scheme, with the game's strategy coming from the intuitively observed differences between characters that felt and acted differently rather than the more ornate combos of two-dimensional competitors. Virtua Fighter's fluid animation and relatively realistic depiction of distinct fighting styles gave its combatants a lifelike presence considered impossible to replicate with sprites. Virtua Fighter played a crucial role in popularizing 3D polygonal graphics. Some of the Sony Computer Entertainment (SCE) staff involved in the creation of the original PlayStation video game console credit Virtua Fighter as inspiration for the PlayStation's 3D graphics hardware. According to SCE's former producer Ryoji Akagawa and chairman Shigeo Maruyama, the PlayStation was originally being considered as a 2D focused hardware, and it was not until the success of Virtua Fighter in the arcades that they decided to design the PlayStation as a 3D focused hardware. Toby Gard also cited Virtua Fighter as an influence on the use of polygon characters—and the creation of Lara Croft—in Tomb Raider: "It became clear to me watching people play Virtua Fighter, which was kind of the first big 3D-character console game, that even though there were only two female characters in the lineup, in almost every game I saw being played, someone was picking one of the two females." John Romero also cited Virtua Fighter as a major influence on the creation of 3D first-person shooter Quake. Team Ico's Fumito Ueda also cited Virtua Fighter as an influence on his animation work. See also Other early 3D fighters: References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Non-player_character#Playability] | [TOKENS: 1785] |
Contents Non-player character A non-player character (NPC) is a character in a game that is not controlled by a player. The term originated in traditional tabletop role-playing games where it applies to characters controlled by the gamemaster, or referee, rather than by another player. In video games, this usually means a computer-controlled character that has a predetermined set of behaviors that potentially will impact gameplay, but will not necessarily be the product of true artificial intelligence. Role-playing games In traditional tabletop role-playing games (RPG) such as Dungeons & Dragons, an NPC is a character portrayed by the gamemaster (GM). While the player characters (PCs) form the narrative's protagonists, non-player characters can be thought of as the "supporting cast" or "extras" of a roleplaying narrative. Non-player characters populate the fictional world of the game, and can fill any role not occupied by a player character. Non-player characters might be allies, bystanders, or competitors to the PCs. NPCs can also be traders who trade currency for things such as equipment or gear. NPCs thus vary in their level of detail. Some may be only a brief description ("You see a man in a corner of the tavern"), while others may have complete game statistics and backstories. There is some debate about how much work a gamemaster should put into an important NPC's statistics; some players prefer to have every NPC completely defined with stats, skills, and gear, while others define only what is immediately necessary and fill in the rest as the game proceeds. There is also some debate regarding the importance of fully defined NPCs in any given role-playing game, but there is consensus that the more "real" the NPCs feel, the more fun players will have interacting with them in character. In some games and in some circumstances, a player who is without a player character can temporarily take control of an NPC. Reasons for this vary, but often arise from the player not maintaining a PC within the group and playing the NPC for a session or from the player's PC being unable to act for some time (for example, because the PC is injured or in another location). Although these characters are still designed and normally controlled by the gamemaster, when players are allowed to temporarily control these non-player characters, it gives them another perspective on the plot of the game. Some systems, such as Nobilis, encourage this in their rules.[citation needed] Many game systems have rules for characters sustaining positive allies in the form of NPC followers, hired hands, or other dependents stature to the PC (player character). Characters may sometimes help in the design, recruitment, or development of NPCs. In the Champions game (and related games using the Hero System), a character may have a DNPC, or "dependent non-player character". This is a character controlled by the GM, but for which the player character is responsible in some way, and who may be put in harm's way by the PC's choices. Video games The term "non-player character" is also used in video games to describe entities not under the direct control of a player. The term carries a connotation that the character is not hostile towards players; hostile characters are referred to as enemies, mobs, or creeps. NPC behavior in computer games is usually scripted and automatic, triggered by certain actions or dialogue with the player characters. In certain multiplayer games (Neverwinter Nights and Vampire: The Masquerade series, for example) a player that acts as the GM can "possess" both player and non-player characters, controlling their actions to further the storyline. More complex games, such as the aforementioned Neverwinter Nights, allow the player to customize the NPCs' behavior by modifying their default scripts or creating entirely new ones. In some online games, such as massively multiplayer online role-playing games, NPCs may be entirely unscripted, and are essentially regular character avatars controlled by employees of the game company. These "non-players" are often distinguished from player characters by avatar appearance or other visual designation, and often serve as in-game support for new players. In other cases, these "live" NPCs are virtual actors, playing regular characters that drive a continuing storyline (as in Myst Online: Uru Live). In earlier RPGs, NPCs only had monologues. This is typically represented by a dialogue box, floating text, cutscene, or other means of displaying the NPCs' speech or reaction to the player. [citation needed] NPC speeches of this kind are often designed to give an instant impression of the character of the speaker, providing character vignettes, but they may also advance the story or illuminate the world around the PC. Similar to this is the most common form of storytelling, non-branching dialogue, in which the means of displaying NPC speech are the same as above, but the player character or avatar responds to or initiates speech with NPCs. In addition to the purposes listed above, this enables the development of the player character. More advanced RPGs feature interactive dialogue, or branching dialogue (dialogue trees). An example are the games produced by Black Isle Studios and White Wolf, Inc.; every one of their games is multiple-choice roleplaying. When talking to an NPC, the player is presented with a list of dialogue options and may choose between them. Each choice may result in a different response from the NPC. These choices may affect the course of the game, as well as the conversation. At the least, they provide a reference point to the player of their character's relationship with the game world. Ultima is an example of a game series that has advanced from non-branching (Ultima III: Exodus and earlier) to branching dialogue (from Ultima IV: Quest of the Avatar and on). Other role-playing games with branching dialogues include Cosmic Soldier, Megami Tensei, Fire Emblem, Metal Max, Langrisser, SaGa, Ogre Battle, Chrono, Star Ocean, Sakura Wars, Mass Effect, Dragon Age, Radiant Historia, and several Dragon Quest and Final Fantasy games. Certain video game genres revolve almost entirely around interactions with non-player characters, including visual novels such as Ace Attorney and dating sims such as Tokimeki Memorial, usually featuring complex branching dialogues and often presenting the player's possible responses word-for-word as the player character would say them. Games revolving around relationship-building, including visual novels, dating sims such as Tokimeki Memorial, and some role-playing games such as Persona, often give choices that have a different number of associated "mood points" that influence a player character's relationship and future conversations with a non-player character. These games often feature a day-night cycle with a time scheduling system that provides context and relevance to character interactions, allowing players to choose when and if to interact with certain characters, which in turn influences their responses during later conversations. In 2023, Replica Studios unveiled its AI-developed NPCs for the Unreal Engine 5, in cooperation with OpenAI, which enable players to have an interactive conversation with unplayable characters. "NPC streaming"—livestreaming while mimicking the behaviors of an NPC—became popular on TikTok in 2023 and was largely popularized by livestreamer Pinkydoll. Other usage From around 2018, the term NPC became an insult, primarily online, to suggest that a person is unable to form thoughts or opinions of their own. This is sometimes illustrated with a grey-faced, expressionless version of the Wojak meme. Monetization NPC streaming is a type of livestream that allows users to participate in and shape the content they are viewing in real time. It has become widely popular as influencers and users of social media platforms such as TikTok utilize livestreams to act as non-player characters. "Viewers in NPC live streams take on the role of puppeteers, influencing the creator's next move." This phenomenon has been on the rise as viewers are actively involved in what they are watching, by purchasing digital "gifts" and sending them directly to the streamer. In return, the streamer will briefly mimic a character or act. This phenomenon has become a trend starting from July 2023, as influencers make profits from this new internet character. Pinkydoll, a TikTok influencer, gained 400,000 followers the same month that she started NPC streaming, while her livestreams began to earn her as much as $7,000 in a day. NPC streaming gives creators a new avenue to earn money online. Despite this, certain creators are quitting due to certain stigmas that come with the strategy. For example, a pioneer of the NPC trend, Malik Ambersley has been robbed, accosted by police, and gotten into fights due to the controversial nature of his act. See also References |
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[SOURCE: https://techcrunch.com/site-map/] | [TOKENS: 253] |
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[SOURCE: https://en.wikipedia.org/wiki/Joke#cite_note-FOOTNOTEDundes198741–54-73] | [TOKENS: 8460] |
Contents Joke A joke is a display of humour in which words are used within a specific and well-defined narrative structure to make people laugh and is usually not meant to be interpreted literally. It usually takes the form of a story, often with dialogue, and ends in a punch line, whereby the humorous element of the story is revealed; this can be done using a pun or other type of word play, irony or sarcasm, logical incompatibility, hyperbole, or other means. Linguist Robert Hetzron offers the definition: A joke is a short humorous piece of oral literature in which the funniness culminates in the final sentence, called the punchline… In fact, the main condition is that the tension should reach its highest level at the very end. No continuation relieving the tension should be added. As for its being "oral," it is true that jokes may appear printed, but when further transferred, there is no obligation to reproduce the text verbatim, as in the case of poetry. It is generally held that jokes benefit from brevity, containing no more detail than is needed to set the scene for the punchline at the end. In the case of riddle jokes or one-liners, the setting is implicitly understood, leaving only the dialogue and punchline to be verbalised. However, subverting these and other common guidelines can also be a source of humour—the shaggy dog story is an example of an anti-joke; although presented as a joke, it contains a long drawn-out narrative of time, place and character, rambles through many pointless inclusions and finally fails to deliver a punchline. Jokes are a form of humour, but not all humour is in the form of a joke. Some humorous forms which are not verbal jokes are: involuntary humour, situational humour, practical jokes, slapstick and anecdotes. Identified as one of the simple forms of oral literature by the Dutch linguist André Jolles, jokes are passed along anonymously. They are told in both private and public settings; a single person tells a joke to his friend in the natural flow of conversation, or a set of jokes is told to a group as part of scripted entertainment. Jokes are also passed along in written form or, more recently, through the internet. Stand-up comics, comedians and slapstick work with comic timing and rhythm in their performance, and may rely on actions as well as on the verbal punchline to evoke laughter. This distinction has been formulated in the popular saying "A comic says funny things; a comedian says things funny".[note 1] History in print Jokes do not belong to refined culture, but rather to the entertainment and leisure of all classes. As such, any printed versions were considered ephemera, i.e., temporary documents created for a specific purpose and intended to be thrown away. Many of these early jokes deal with scatological and sexual topics, entertaining to all social classes but not to be valued and saved.[citation needed] Various kinds of jokes have been identified in ancient pre-classical texts.[note 2] The oldest identified joke is an ancient Sumerian proverb from 1900 BC containing toilet humour: "Something which has never occurred since time immemorial; a young woman did not fart in her husband's lap." Its records were dated to the Old Babylonian period and the joke may go as far back as 2300 BC. The second oldest joke found, discovered on the Westcar Papyrus and believed to be about Sneferu, was from Ancient Egypt c. 1600 BC: "How do you entertain a bored pharaoh? You sail a boatload of young women dressed only in fishing nets down the Nile and urge the pharaoh to go catch a fish." The tale of the three ox drivers from Adab completes the three known oldest jokes in the world. This is a comic triple dating back to 1200 BC Adab. It concerns three men seeking justice from a king on the matter of ownership over a newborn calf, for whose birth they all consider themselves to be partially responsible. The king seeks advice from a priestess on how to rule the case, and she suggests a series of events involving the men's households and wives. The final portion of the story (which included the punch line), has not survived intact, though legible fragments suggest it was bawdy in nature. Jokes can be notoriously difficult to translate from language to language; particularly puns, which depend on specific words and not just on their meanings. For instance, Julius Caesar once sold land at a surprisingly cheap price to his lover Servilia, who was rumoured to be prostituting her daughter Tertia to Caesar in order to keep his favour. Cicero remarked that "conparavit Servilia hunc fundum tertia deducta." The punny phrase, "tertia deducta", can be translated as "with one-third off (in price)", or "with Tertia putting out." The earliest extant joke book is the Philogelos (Greek for The Laughter-Lover), a collection of 265 jokes written in crude ancient Greek dating to the fourth or fifth century AD. The author of the collection is obscure and a number of different authors are attributed to it, including "Hierokles and Philagros the grammatikos", just "Hierokles", or, in the Suda, "Philistion". British classicist Mary Beard states that the Philogelos may have been intended as a jokester's handbook of quips to say on the fly, rather than a book meant to be read straight through. Many of the jokes in this collection are surprisingly familiar, even though the typical protagonists are less recognisable to contemporary readers: the absent-minded professor, the eunuch, and people with hernias or bad breath. The Philogelos even contains a joke similar to Monty Python's "Dead Parrot Sketch". During the 15th century, the printing revolution spread across Europe following the development of the movable type printing press. This was coupled with the growth of literacy in all social classes. Printers turned out Jestbooks along with Bibles to meet both lowbrow and highbrow interests of the populace. One early anthology of jokes was the Facetiae by the Italian Poggio Bracciolini, first published in 1470. The popularity of this jest book can be measured on the twenty editions of the book documented alone for the 15th century. Another popular form was a collection of jests, jokes and funny situations attributed to a single character in a more connected, narrative form of the picaresque novel. Examples of this are the characters of Rabelais in France, Till Eulenspiegel in Germany, Lazarillo de Tormes in Spain and Master Skelton in England. There is also a jest book ascribed to William Shakespeare, the contents of which appear to both inform and borrow from his plays. All of these early jestbooks corroborate both the rise in the literacy of the European populations and the general quest for leisure activities during the Renaissance in Europe. The practice of printers using jokes and cartoons as page fillers was also widely used in the broadsides and chapbooks of the 19th century and earlier. With the increase in literacy in the general population and the growth of the printing industry, these publications were the most common forms of printed material between the 16th and 19th centuries throughout Europe and North America. Along with reports of events, executions, ballads and verse, they also contained jokes. Only one of many broadsides archived in the Harvard library is described as "1706. Grinning made easy; or, Funny Dick's unrivalled collection of curious, comical, odd, droll, humorous, witty, whimsical, laughable, and eccentric jests, jokes, bulls, epigrams, &c. With many other descriptions of wit and humour." These cheap publications, ephemera intended for mass distribution, were read alone, read aloud, posted and discarded. There are many types of joke books in print today; a search on the internet provides a plethora of titles available for purchase. They can be read alone for solitary entertainment, or used to stock up on new jokes to entertain friends. Some people try to find a deeper meaning in jokes, as in "Plato and a Platypus Walk into a Bar... Understanding Philosophy Through Jokes".[note 3] However a deeper meaning is not necessary to appreciate their inherent entertainment value. Magazines frequently use jokes and cartoons as filler for the printed page. Reader's Digest closes out many articles with an (unrelated) joke at the bottom of the article. The New Yorker was first published in 1925 with the stated goal of being a "sophisticated humour magazine" and is still known for its cartoons. Telling jokes Telling a joke is a cooperative effort; it requires that the teller and the audience mutually agree in one form or another to understand the narrative which follows as a joke. In a study of conversation analysis, the sociologist Harvey Sacks describes in detail the sequential organisation in the telling of a single joke. "This telling is composed, as for stories, of three serially ordered and adjacently placed types of sequences … the preface [framing], the telling, and the response sequences." Folklorists expand this to include the context of the joking. Who is telling what jokes to whom? And why is he telling them when? The context of the joke-telling in turn leads into a study of joking relationships, a term coined by anthropologists to refer to social groups within a culture who engage in institutionalised banter and joking. Framing is done with a (frequently formulaic) expression which keys the audience in to expect a joke. "Have you heard the one…", "Reminds me of a joke I heard…", "So, a lawyer and a doctor…"; these conversational markers are just a few examples of linguistic frames used to start a joke. Regardless of the frame used, it creates a social space and clear boundaries around the narrative which follows. Audience response to this initial frame can be acknowledgement and anticipation of the joke to follow. It can also be a dismissal, as in "this is no joking matter" or "this is no time for jokes". The performance frame serves to label joke-telling as a culturally marked form of communication. Both the performer and audience understand it to be set apart from the "real" world. "An elephant walks into a bar…"; a person sufficiently familiar with both the English language and the way jokes are told automatically understands that such a compressed and formulaic story, being told with no substantiating details, and placing an unlikely combination of characters into an unlikely setting and involving them in an unrealistic plot, is the start of a joke, and the story that follows is not meant to be taken at face value (i.e. it is non-bona-fide communication). The framing itself invokes a play mode; if the audience is unable or unwilling to move into play, then nothing will seem funny. Following its linguistic framing the joke, in the form of a story, can be told. It is not required to be verbatim text like other forms of oral literature such as riddles and proverbs. The teller can and does modify the text of the joke, depending both on memory and the present audience. The important characteristic is that the narrative is succinct, containing only those details which lead directly to an understanding and decoding of the punchline. This requires that it support the same (or similar) divergent scripts which are to be embodied in the punchline. The punchline is intended to make the audience laugh. A linguistic interpretation of this punchline/response is elucidated by Victor Raskin in his Script-based Semantic Theory of Humour. Humour is evoked when a trigger contained in the punchline causes the audience to abruptly shift its understanding of the story from the primary (or more obvious) interpretation to a secondary, opposing interpretation. "The punchline is the pivot on which the joke text turns as it signals the shift between the [semantic] scripts necessary to interpret [re-interpret] the joke text." To produce the humour in the verbal joke, the two interpretations (i.e. scripts) need to both be compatible with the joke text and opposite or incompatible with each other. Thomas R. Shultz, a psychologist, independently expands Raskin's linguistic theory to include "two stages of incongruity: perception and resolution." He explains that "… incongruity alone is insufficient to account for the structure of humour. […] Within this framework, humour appreciation is conceptualized as a biphasic sequence involving first the discovery of incongruity followed by a resolution of the incongruity." In the case of a joke, that resolution generates laughter. This is the point at which the field of neurolinguistics offers some insight into the cognitive processing involved in this abrupt laughter at the punchline. Studies by the cognitive science researchers Coulson and Kutas directly address the theory of script switching articulated by Raskin in their work. The article "Getting it: Human event-related brain response to jokes in good and poor comprehenders" measures brain activity in response to reading jokes. Additional studies by others in the field support more generally the theory of two-stage processing of humour, as evidenced in the longer processing time they require. In the related field of neuroscience, it has been shown that the expression of laughter is caused by two partially independent neuronal pathways: an "involuntary" or "emotionally driven" system and a "voluntary" system. This study adds credence to the common experience when exposed to an off-colour joke; a laugh is followed in the next breath by a disclaimer: "Oh, that's bad…" Here the multiple steps in cognition are clearly evident in the stepped response, the perception being processed just a breath faster than the resolution of the moral/ethical content in the joke. Expected response to a joke is laughter. The joke teller hopes the audience "gets it" and is entertained. This leads to the premise that a joke is actually an "understanding test" between individuals and groups. If the listeners do not get the joke, they are not understanding the two scripts which are contained in the narrative as they were intended. Or they do "get it" and do not laugh; it might be too obscene, too gross or too dumb for the current audience. A woman might respond differently to a joke told by a male colleague around the water cooler than she would to the same joke overheard in a women's lavatory. A joke involving toilet humour may be funnier told on the playground at elementary school than on a college campus. The same joke will elicit different responses in different settings. The punchline in the joke remains the same, however, it is more or less appropriate depending on the current context. The context explores the specific social situation in which joking occurs. The narrator automatically modifies the text of the joke to be acceptable to different audiences, while at the same time supporting the same divergent scripts in the punchline. The vocabulary used in telling the same joke at a university fraternity party and to one's grandmother might well vary. In each situation, it is important to identify both the narrator and the audience as well as their relationship with each other. This varies to reflect the complexities of a matrix of different social factors: age, sex, race, ethnicity, kinship, political views, religion, power relationships, etc. When all the potential combinations of such factors between the narrator and the audience are considered, then a single joke can take on infinite shades of meaning for each unique social setting. The context, however, should not be confused with the function of the joking. "Function is essentially an abstraction made on the basis of a number of contexts". In one long-term observation of men coming off the late shift at a local café, joking with the waitresses was used to ascertain sexual availability for the evening. Different types of jokes, going from general to topical into explicitly sexual humour signalled openness on the part of the waitress for a connection. This study describes how jokes and joking are used to communicate much more than just good humour. That is a single example of the function of joking in a social setting, but there are others. Sometimes jokes are used simply to get to know someone better. What makes them laugh, what do they find funny? Jokes concerning politics, religion or sexual topics can be used effectively to gauge the attitude of the audience to any one of these topics. They can also be used as a marker of group identity, signalling either inclusion or exclusion for the group. Among pre-adolescents, "dirty" jokes allow them to share information about their changing bodies. And sometimes joking is just simple entertainment for a group of friends. Relationships The context of joking in turn leads to a study of joking relationships, a term coined by anthropologists to refer to social groups within a culture who take part in institutionalised banter and joking. These relationships can be either one-way or a mutual back and forth between partners. The joking relationship is defined as a peculiar combination of friendliness and antagonism. The behaviour is such that in any other social context it would express and arouse hostility; but it is not meant seriously and must not be taken seriously. There is a pretence of hostility along with a real friendliness. To put it in another way, the relationship is one of permitted disrespect. Joking relationships were first described by anthropologists within kinship groups in Africa. But they have since been identified in cultures around the world, where jokes and joking are used to mark and reinforce appropriate boundaries of a relationship. Electronic The advent of electronic communications at the end of the 20th century introduced new traditions into jokes. A verbal joke or cartoon is emailed to a friend or posted on a bulletin board; reactions include a replied email with a :-) or LOL, or a forward on to further recipients. Interaction is limited to the computer screen and for the most part solitary. While preserving the text of a joke, both context and variants are lost in internet joking; for the most part, emailed jokes are passed along verbatim. The framing of the joke frequently occurs in the subject line: "RE: laugh for the day" or something similar. The forward of an email joke can increase the number of recipients exponentially. Internet joking forces a re-evaluation of social spaces and social groups. They are no longer only defined by physical presence and locality, they also exist in the connectivity in cyberspace. "The computer networks appear to make possible communities that, although physically dispersed, display attributes of the direct, unconstrained, unofficial exchanges folklorists typically concern themselves with". This is particularly evident in the spread of topical jokes, "that genre of lore in which whole crops of jokes spring up seemingly overnight around some sensational event … flourish briefly and then disappear, as the mass media move on to fresh maimings and new collective tragedies". This correlates with the new understanding of the internet as an "active folkloric space" with evolving social and cultural forces and clearly identifiable performers and audiences. A study by the folklorist Bill Ellis documented how an evolving cycle was circulated over the internet. By accessing message boards that specialised in humour immediately following the 9/11 disaster, Ellis was able to observe in real-time both the topical jokes being posted electronically and responses to the jokes. Previous folklore research has been limited to collecting and documenting successful jokes, and only after they had emerged and come to folklorists' attention. Now, an Internet-enhanced collection creates a time machine, as it were, where we can observe what happens in the period before the risible moment, when attempts at humour are unsuccessful Access to archived message boards also enables us to track the development of a single joke thread in the context of a more complicated virtual conversation. Joke cycles A joke cycle is a collection of jokes about a single target or situation which displays consistent narrative structure and type of humour. Some well-known cycles are elephant jokes using nonsense humour, dead baby jokes incorporating black humour, and light bulb jokes, which describe all kinds of operational stupidity. Joke cycles can centre on ethnic groups, professions (viola jokes), catastrophes, settings (…walks into a bar), absurd characters (wind-up dolls), or logical mechanisms which generate the humour (knock-knock jokes). A joke can be reused in different joke cycles; an example of this is the same Head & Shoulders joke refitted to the tragedies of Vic Morrow, Admiral Mountbatten and the crew of the Challenger space shuttle.[note 4] These cycles seem to appear spontaneously, spread rapidly across countries and borders only to dissipate after some time. Folklorists and others have studied individual joke cycles in an attempt to understand their function and significance within the culture. Joke cycles circulated in the recent past include: As with the 9/11 disaster discussed above, cycles attach themselves to celebrities or national catastrophes such as the death of Diana, Princess of Wales, the death of Michael Jackson, and the Space Shuttle Challenger disaster. These cycles arise regularly as a response to terrible unexpected events which command the national news. An in-depth analysis of the Challenger joke cycle documents a change in the type of humour circulated following the disaster, from February to March 1986. "It shows that the jokes appeared in distinct 'waves', the first responding to the disaster with clever wordplay and the second playing with grim and troubling images associated with the event…The primary social function of disaster jokes appears to be to provide closure to an event that provoked communal grieving, by signalling that it was time to move on and pay attention to more immediate concerns". The sociologist Christie Davies has written extensively on ethnic jokes told in countries around the world. In ethnic jokes he finds that the "stupid" ethnic target in the joke is no stranger to the culture, but rather a peripheral social group (geographic, economic, cultural, linguistic) well known to the joke tellers. So Americans tell jokes about Polacks and Italians, Germans tell jokes about Ostfriesens, and the English tell jokes about the Irish. In a review of Davies' theories it is said that "For Davies, [ethnic] jokes are more about how joke tellers imagine themselves than about how they imagine those others who serve as their putative targets…The jokes thus serve to center one in the world – to remind people of their place and to reassure them that they are in it." A third category of joke cycles identifies absurd characters as the butt: for example the grape, the dead baby or the elephant. Beginning in the 1960s, social and cultural interpretations of these joke cycles, spearheaded by the folklorist Alan Dundes, began to appear in academic journals. Dead baby jokes are posited to reflect societal changes and guilt caused by widespread use of contraception and abortion beginning in the 1960s.[note 5] Elephant jokes have been interpreted variously as stand-ins for American blacks during the Civil Rights Era or as an "image of something large and wild abroad in the land captur[ing] the sense of counterculture" of the sixties. These interpretations strive for a cultural understanding of the themes of these jokes which go beyond the simple collection and documentation undertaken previously by folklorists and ethnologists. Classification systems As folktales and other types of oral literature became collectables throughout Europe in the 19th century (Brothers Grimm et al.), folklorists and anthropologists of the time needed a system to organise these items. The Aarne–Thompson classification system was first published in 1910 by Antti Aarne, and later expanded by Stith Thompson to become the most renowned classification system for European folktales and other types of oral literature. Its final section addresses anecdotes and jokes, listing traditional humorous tales ordered by their protagonist; "This section of the Index is essentially a classification of the older European jests, or merry tales – humorous stories characterized by short, fairly simple plots. …" Due to its focus on older tale types and obsolete actors (e.g., numbskull), the Aarne–Thompson Index does not provide much help in identifying and classifying the modern joke. A more granular classification system used widely by folklorists and cultural anthropologists is the Thompson Motif Index, which separates tales into their individual story elements. This system enables jokes to be classified according to individual motifs included in the narrative: actors, items and incidents. It does not provide a system to classify the text by more than one element at a time while at the same time making it theoretically possible to classify the same text under multiple motifs. The Thompson Motif Index has spawned further specialised motif indices, each of which focuses on a single aspect of one subset of jokes. A sampling of just a few of these specialised indices have been listed under other motif indices. Here one can select an index for medieval Spanish folk narratives, another index for linguistic verbal jokes, and a third one for sexual humour. To assist the researcher with this increasingly confusing situation, there are also multiple bibliographies of indices as well as a how-to guide on creating your own index. Several difficulties have been identified with these systems of identifying oral narratives according to either tale types or story elements. A first major problem is their hierarchical organisation; one element of the narrative is selected as the major element, while all other parts are arrayed subordinate to this. A second problem with these systems is that the listed motifs are not qualitatively equal; actors, items and incidents are all considered side-by-side. And because incidents will always have at least one actor and usually have an item, most narratives can be ordered under multiple headings. This leads to confusion about both where to order an item and where to find it. A third significant problem is that the "excessive prudery" common in the middle of the 20th century means that obscene, sexual and scatological elements were regularly ignored in many of the indices. The folklorist Robert Georges has summed up the concerns with these existing classification systems: …Yet what the multiplicity and variety of sets and subsets reveal is that folklore [jokes] not only takes many forms, but that it is also multifaceted, with purpose, use, structure, content, style, and function all being relevant and important. Any one or combination of these multiple and varied aspects of a folklore example [such as jokes] might emerge as dominant in a specific situation or for a particular inquiry. It has proven difficult to organise all different elements of a joke into a multi-dimensional classification system which could be of real value in the study and evaluation of this (primarily oral) complex narrative form. The General Theory of Verbal Humour or GTVH, developed by the linguists Victor Raskin and Salvatore Attardo, attempts to do exactly this. This classification system was developed specifically for jokes and later expanded to include longer types of humorous narratives. Six different aspects of the narrative, labelled Knowledge Resources or KRs, can be evaluated largely independently of each other, and then combined into a concatenated classification label. These six KRs of the joke structure include: As development of the GTVH progressed, a hierarchy of the KRs was established to partially restrict the options for lower-level KRs depending on the KRs defined above them. For example, a lightbulb joke (SI) will always be in the form of a riddle (NS). Outside of these restrictions, the KRs can create a multitude of combinations, enabling a researcher to select jokes for analysis which contain only one or two defined KRs. It also allows for an evaluation of the similarity or dissimilarity of jokes depending on the similarity of their labels. "The GTVH presents itself as a mechanism … of generating [or describing] an infinite number of jokes by combining the various values that each parameter can take. … Descriptively, to analyze a joke in the GTVH consists of listing the values of the 6 KRs (with the caveat that TA and LM may be empty)." This classification system provides a functional multi-dimensional label for any joke, and indeed any verbal humour. Joke and humour research Many academic disciplines lay claim to the study of jokes (and other forms of humour) as within their purview. Fortunately, there are enough jokes, good, bad and worse, to go around. The studies of jokes from each of the interested disciplines bring to mind the tale of the blind men and an elephant where the observations, although accurate reflections of their own competent methodological inquiry, frequently fail to grasp the beast in its entirety. This attests to the joke as a traditional narrative form which is indeed complex, concise and complete in and of itself. It requires a "multidisciplinary, interdisciplinary, and cross-disciplinary field of inquiry" to truly appreciate these nuggets of cultural insight.[note 6] Sigmund Freud was one of the first modern scholars to recognise jokes as an important object of investigation. In his 1905 study Jokes and their Relation to the Unconscious Freud describes the social nature of humour and illustrates his text with many examples of contemporary Viennese jokes. His work is particularly noteworthy in this context because Freud distinguishes in his writings between jokes, humour and the comic. These are distinctions which become easily blurred in many subsequent studies where everything funny tends to be gathered under the umbrella term of "humour", making for a much more diffuse discussion. Since the publication of Freud's study, psychologists have continued to explore humour and jokes in their quest to explain, predict and control an individual's "sense of humour". Why do people laugh? Why do people find something funny? Can jokes predict character, or vice versa, can character predict the jokes an individual laughs at? What is a "sense of humour"? A current review of the popular magazine Psychology Today lists over 200 articles discussing various aspects of humour; in psychological jargon, the subject area has become both an emotion to measure and a tool to use in diagnostics and treatment. A new psychological assessment tool, the Values in Action Inventory developed by the American psychologists Christopher Peterson and Martin Seligman includes humour (and playfulness) as one of the core character strengths of an individual. As such, it could be a good predictor of life satisfaction. For psychologists, it would be useful to measure both how much of this strength an individual has and how it can be measurably increased. A 2007 survey of existing tools to measure humour identified more than 60 psychological measurement instruments. These measurement tools use many different approaches to quantify humour along with its related states and traits. There are tools to measure an individual's physical response by their smile; the Facial Action Coding System (FACS) is one of several tools used to identify any one of multiple types of smiles. Or the laugh can be measured to calculate the funniness response of an individual; multiple types of laughter have been identified. It must be stressed here that both smiles and laughter are not always a response to something funny. In trying to develop a measurement tool, most systems use "jokes and cartoons" as their test materials. However, because no two tools use the same jokes, and across languages this would not be feasible, how does one determine that the assessment objects are comparable? Moving on, whom does one ask to rate the sense of humour of an individual? Does one ask the person themselves, an impartial observer, or their family, friends and colleagues? Furthermore, has the current mood of the test subjects been considered; someone with a recent death in the family might not be much prone to laughter. Given the plethora of variants revealed by even a superficial glance at the problem, it becomes evident that these paths of scientific inquiry are mined with problematic pitfalls and questionable solutions. The psychologist Willibald Ruch [de] has been very active in the research of humour. He has collaborated with the linguists Raskin and Attardo on their General Theory of Verbal Humour (GTVH) classification system. Their goal is to empirically test both the six autonomous classification types (KRs) and the hierarchical ordering of these KRs. Advancement in this direction would be a win-win for both fields of study; linguistics would have empirical verification of this multi-dimensional classification system for jokes, and psychology would have a standardised joke classification with which they could develop verifiably comparable measurement tools. "The linguistics of humor has made gigantic strides forward in the last decade and a half and replaced the psychology of humor as the most advanced theoretical approach to the study of this important and universal human faculty." This recent statement by one noted linguist and humour researcher describes, from his perspective, contemporary linguistic humour research. Linguists study words, how words are strung together to build sentences, how sentences create meaning which can be communicated from one individual to another, and how our interaction with each other using words creates discourse. Jokes have been defined above as oral narratives in which words and sentences are engineered to build toward a punchline. The linguist's question is: what exactly makes the punchline funny? This question focuses on how the words used in the punchline create humour, in contrast to the psychologist's concern (see above) with the audience's response to the punchline. The assessment of humour by psychologists "is made from the individual's perspective; e.g. the phenomenon associated with responding to or creating humor and not a description of humor itself." Linguistics, on the other hand, endeavours to provide a precise description of what makes a text funny. Two major new linguistic theories have been developed and tested within the last decades. The first was advanced by Victor Raskin in "Semantic Mechanisms of Humor", published 1985. While being a variant on the more general concepts of the incongruity theory of humour, it is the first theory to identify its approach as exclusively linguistic. The Script-based Semantic Theory of Humour (SSTH) begins by identifying two linguistic conditions which make a text funny. It then goes on to identify the mechanisms involved in creating the punchline. This theory established the semantic/pragmatic foundation of humour as well as the humour competence of speakers.[note 7] Several years later the SSTH was incorporated into a more expansive theory of jokes put forth by Raskin and his colleague Salvatore Attardo. In the General Theory of Verbal Humour, the SSTH was relabelled as a Logical Mechanism (LM) (referring to the mechanism which connects the different linguistic scripts in the joke) and added to five other independent Knowledge Resources (KR). Together these six KRs could now function as a multi-dimensional descriptive label for any piece of humorous text. Linguistics has developed further methodological tools which can be applied to jokes: discourse analysis and conversation analysis of joking. Both of these subspecialties within the field focus on "naturally occurring" language use, i.e. the analysis of real (usually recorded) conversations. One of these studies has already been discussed above, where Harvey Sacks describes in detail the sequential organisation in telling a single joke. Discourse analysis emphasises the entire context of social joking, the social interaction which cradles the words. Folklore and cultural anthropology have perhaps the strongest claims on jokes as belonging to their bailiwick. Jokes remain one of the few remaining forms of traditional folk literature transmitted orally in western cultures. Identified as one of the "simple forms" of oral literature by André Jolles in 1930, they have been collected and studied since there were folklorists and anthropologists abroad in the lands. As a genre they were important enough at the beginning of the 20th century to be included under their own heading in the Aarne–Thompson index first published in 1910: Anecdotes and jokes. Beginning in the 1960s, cultural researchers began to expand their role from collectors and archivists of "folk ideas" to a more active role of interpreters of cultural artefacts. One of the foremost scholars active during this transitional time was the folklorist Alan Dundes. He started asking questions of tradition and transmission with the key observation that "No piece of folklore continues to be transmitted unless it means something, even if neither the speaker nor the audience can articulate what that meaning might be." In the context of jokes, this then becomes the basis for further research. Why is the joke told right now? Only in this expanded perspective is an understanding of its meaning to the participants possible. This questioning resulted in a blossoming of monographs to explore the significance of many joke cycles. What is so funny about absurd nonsense elephant jokes? Why make light of dead babies? In an article on contemporary German jokes about Auschwitz and the Holocaust, Dundes justifies this research: Whether one finds Auschwitz jokes funny or not is not an issue. This material exists and should be recorded. Jokes are always an important barometer of the attitudes of a group. The jokes exist and they obviously must fill some psychic need for those individuals who tell them and those who listen to them. A stimulating generation of new humour theories flourishes like mushrooms in the undergrowth: Elliott Oring's theoretical discussions on "appropriate ambiguity" and Amy Carrell's hypothesis of an "audience-based theory of verbal humor (1993)" to name just a few. In his book Humor and Laughter: An Anthropological Approach, the anthropologist Mahadev Apte presents a solid case for his own academic perspective. "Two axioms underlie my discussion, namely, that humor is by and large culture based and that humor can be a major conceptual and methodological tool for gaining insights into cultural systems." Apte goes on to call for legitimising the field of humour research as "humorology"; this would be a field of study incorporating an interdisciplinary character of humour studies. While the label "humorology" has yet to become a household word, great strides are being made in the international recognition of this interdisciplinary field of research. The International Society for Humor Studies was founded in 1989 with the stated purpose to "promote, stimulate and encourage the interdisciplinary study of humour; to support and cooperate with local, national, and international organizations having similar purposes; to organize and arrange meetings; and to issue and encourage publications concerning the purpose of the society". It also publishes Humor: International Journal of Humor Research and holds yearly conferences to promote and inform its speciality. In 1872, Charles Darwin published one of the first "comprehensive and in many ways remarkably accurate description of laughter in terms of respiration, vocalization, facial action and gesture and posture" (Laughter) in The Expression of the Emotions in Man and Animals. In this early study Darwin raises further questions about who laughs and why they laugh; the myriad responses since then illustrate the complexities of this behaviour. To understand laughter in humans and other primates, the science of gelotology (from the Greek gelos, meaning laughter) has been established; it is the study of laughter and its effects on the body from both a psychological and physiological perspective. While jokes can provoke laughter, laughter cannot be used as a one-to-one marker of jokes because there are multiple stimuli to laughter, humour being just one of them. The other six causes of laughter listed are social context, ignorance, anxiety, derision, acting apology, and tickling. As such, the study of laughter is a secondary albeit entertaining perspective in an understanding of jokes. Computational humour is a new field of study which uses computers to model humour; it bridges the disciplines of computational linguistics and artificial intelligence. A primary ambition of this field is to develop computer programs which can both generate a joke and recognise a text snippet as a joke. Early programming attempts have dealt almost exclusively with punning because this lends itself to simple straightforward rules. These primitive programs display no intelligence; instead, they work off a template with a finite set of pre-defined punning options upon which to build. More sophisticated computer joke programs have yet to be developed. Based on our understanding of the SSTH / GTVH humour theories, it is easy to see why. The linguistic scripts (a.k.a. frames) referenced in these theories include, for any given word, a "large chunk of semantic information surrounding the word and evoked by it [...] a cognitive structure internalized by the native speaker". These scripts extend much further than the lexical definition of a word; they contain the speaker's complete knowledge of the concept as it exists in his world. As insentient machines, computers lack the encyclopaedic scripts which humans gain through life experience. They also lack the ability to gather the experiences needed to build wide-ranging semantic scripts and understand language in a broader context, a context that any child picks up in daily interaction with his environment. Further development in this field must wait until computational linguists have succeeded in programming a computer with an ontological semantic natural language processing system. It is only "the most complex linguistic structures [which] can serve any formal and/or computational treatment of humor well". Toy systems (i.e. dummy punning programs) are completely inadequate to the task. Despite the fact that the field of computational humour is small and underdeveloped, it is encouraging to note the many interdisciplinary efforts which are currently underway. See also Notes References Further reading |
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[SOURCE: https://en.wikipedia.org/wiki/Siberia] | [TOKENS: 7149] |
Contents Siberia Siberia (/saɪˈbɪəriə/ sy-BEER-ee-ə; Russian: Сибирь, romanized: Sibir', IPA: [sʲɪˈbʲirʲ] ⓘ), also known as Asian Russia, is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west (with the Ural River usually forming the southernmost portion of its western boundary) to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states since the lengthy conquest of Siberia, which began with the fall of the Khanate of Sibir in 1582 and concluded with the annexation of Chukotka in 1778. Siberia is vast and sparsely populated, covering an area of over 13.1 million square kilometres (5,100,000 mi2) – about three-quarters of Russia's total area, but home to roughly a quarter of Russia's population. Novosibirsk, Krasnoyarsk, and Omsk are the largest cities in the area. Because Siberia is a geographic and historic concept and not a political entity, there is no single precise definition of its territorial borders. It is further defined as stretching from the territories within the Arctic Circle in the north to the northern borders of Kazakhstan, Mongolia, and China in the south, although the hills of north-central Kazakhstan are also commonly included. The Russian government divides the region into three federal districts (groupings of Russian federal subjects), of which only the central one is officially referred to as "Siberian"; the other two are the Ural and Far Eastern federal districts, named for the Ural and Russian Far East regions that correspond respectively to the western and eastern thirds of Siberia in the broader sense. Siberia is known for its long, harsh winters, with a January average of −25 °C (−13 °F). Although it is geographically located in Asia, Russian sovereignty and colonization since the 16th century has led to perceptions of the region as culturally and ethnically European. Over 85% of its population are of European descent, chiefly Russian (comprising the Siberian sub-ethnic group), and Eastern Slavic cultural influences predominate throughout the region. Nevertheless, there exist sizable ethnic minorities of Asian lineage, including various Turkic communities—many of which, such as the Yakuts, Tuvans, Altai, and Khakas, are Indigenous—along with the Mongolic Buryats, ethnic Koreans, and smaller groups of Samoyedic and Tungusic peoples (several of whom are classified as Indigenous small-numbered peoples by the Russian government), among many others. Etymology The origin of the name is uncertain. In the Russian language, it was adopted as a toponym through contact with the Khanate of Sibir (Сибирское ханство) since the 15th century. The Russian name Yugra was applied to the northern lands east of the Ural Mountains, which had been known of since the 11th century or earlier, while the name Siberia is first mentioned in Russian chronicles at the start of the 15th century in connection with the death of the khan Tokhtamysh in "the Siberian land". Some sources say that "Siberia" originates from the Siberian Tatar word for 'sleeping land' (Sib-ir), but this discourse does not correspond to the actual Siberian Tatar language. Mongolist György Kara posits that the toponym Siberia is derived from a Mongolic word sibir, cognate with modern Buryat sheber 'dense forest'. A different hypothesis claims that the region was named after the Sibe people. Another account sees the name as the ancient tribal ethnonym of the Sihirtia or Sirtya (also Sypyr [sʲɵpᵻr])), a hypothetical Paleo-Asiatic ethnic group assimilated by the Nenets.[citation needed] Polish historian Jan Chyliczkowski has proposed that the name derives from the Proto-Slavic word for 'north' (cf. Russian север sever), as in Severia. Anatole Baikaloff has dismissed this explanation. He says that the neighboring Chinese, Turks, and Mongolians, who have similar names for the region, would not have known Russian. He suggests that the name might be a combination of two words with Turkic origin, su 'water' and bir 'wild land'. History Siberia in Paleozoic times formed the continent of Siberia/Angaraland, which fused to Euramerica during the Late Carboniferous, as part of the formation of Pangea. The Siberian Traps were formed by one of the largest-known volcanic events of the last 251 million years of Earth's geological history. Their activity continued for a million years, and some scientists consider it a possible cause of the "Great Dying" about 250 million years ago, estimated to have killed 90% of species existing at the time. The region has paleontological significance, as it contains bodies of prehistoric animals from the Pleistocene Epoch, preserved in ice or permafrost. Specimens of Goldfuss cave lion cubs, Yuka the mammoth and another woolly mammoth from Oymyakon, a woolly rhinoceros from the Kolyma, and bison and horses from Yukagir have been found. Remote Wrangel Island and the Taymyr Peninsula are believed to have been the last places on Earth to support woolly mammoths as isolated populations until their extinction around 2000 BC. At least three species of humans lived in southern Siberia around 40,000 years ago: H. sapiens, H. neanderthalensis, and the Denisovans. In 2010, DNA evidence identified the last as a separate species. Late Paleolithic southern Siberians appear to be related to Paleolithic Europeans and the Paleolithic Jōmon people of Japan. DNA analysis has revealed that the oldest fossil known to carry the derived KITLG allele, which is responsible for blond hair in modern Europeans, is a 17,000 year old Ancient North Eurasian specimen from Siberia. Ancient North Eurasian populations genetically similar to Mal'ta–Buret' culture and Afontova Gora were an important genetic contributor to Native Americans, Europeans, Ancient Central Asians, South Asians, and some East Asian groups (such as the Ainu people). Evidence from full genomic studies suggests that the first people in the Americas diverged from Ancient East Asians about 36,000 years ago and expanded northwards into Siberia, where they encountered and interacted with Ancient North Eurasians, giving rise to both Paleosiberian peoples and Ancient Native Americans, which later migrated towards the Beringian region, became isolated from other populations, and subsequently populated the Americas. During past millennia, different groups of nomads – such as the Enets, the Nenets, the Huns, the Xiongnu, the Scythians, and the Yugur – inhabited various parts of Siberia. The Afanasievo and Tashtyk cultures of the Yenisey valley and Altay Mountains are associated with the Indo-European migrations across Eurasia. The proto-Mongol Khitan people, whose territory spanned a vast area, were also attested in the Ob region of western Siberia in the sixteenth century. In the 13th century, during the period of the Mongol Empire, the Mongols conquered a large part of this area. With the breakup of the Golden Horde, the autonomous Khanate of Sibir was formed in the late-15th century. Turkic-speaking Yakut migrated north from the Lake Baikal region under pressure from the Mongol tribes from the 13th to 15th centuries. Siberia remained a sparsely populated area. Historian John F. Richards writes: "it is doubtful that the total early modern Siberian population exceeded 300,000 persons". The first mention of Siberia in chronicles is recorded in 1032. The city-state of Novgorod established two trade routes to the Ob River, and laid claim to the lands the Russians called Yugra. The Russians were attracted by its furs in particular. Novgorod launched military campaigns to extract tribute from the local population but often met resistance, such as two campaigns in 1187 and 1193 mentioned in chronicles that were defeated. After Novgorod was annexed by Moscow, the newly emerging centralized Russian state also laid claim to the region, with Ivan III of Russia sending expeditionary forces to Siberia in 1483 and 1499–1500. The Russians received tribute, but contact with the tribes ceased after they left. The growing power of the Tsardom of Russia began to undermine the Siberian Khanate in the 16th century. First, groups of traders and Cossacks began to enter the area. The Russian army was directed to establish forts farther and farther east to protect new Russian settlers who migrated from Europe. Towns such as Mangazeya, Tara, Yeniseysk, and Tobolsk developed, the last becoming the de facto capital of Siberia from 1590. At this time, Sibir was the name of a fortress at Qashliq, near Tobolsk. Gerardus Mercator, in a map published in 1595, marks Sibier both as the name of a settlement and of the surrounding territory along a left tributary of the Ob. Other sources[which?] contend that the Sibe, an indigenous Tungusic people, offered fierce resistance to Russian expansion beyond the Urals. Some suggest that the term "Siberia" is a Russified version of their ethnonym. By the mid-17th century, Russia had established areas of control that extended to the Pacific Ocean. Some 230,000 Russians had settled in Siberia by 1709. Siberia became one of the destinations for sending internal exiles. Exile was the main Russian punitive practice with more than 800,000 people exiled during the 19th century. The first great modern change in Siberia was the Trans-Siberian Railway, constructed during 1891–1916. It linked Siberia more closely to the rapidly industrialising Russia of Nicholas II. Around seven million Russians moved to Siberia from Europe between 1801 and 1914. Between 1859 and 1917, more than half a million people migrated to the Russian Far East. Siberia has extensive natural resources: during the 20th century, large-scale exploitation of these took place, and industrial towns cropped up throughout the region. At 7:15 a.m. on 30 June 1908, the Tunguska event felled millions of trees near the Podkamennaya Tunguska River (Stony Tunguska River) in central Siberia. Most scientists believe this resulted from the air burst of a meteor or comet. Even though no crater has ever been found, the landscape in the (sparsely inhabited) area still bears the scars of this event. In the early decades of the Soviet Union (especially in the 1930s and 1940s), the government used the Gulag state agency to administer a system of penal labour camps, replacing the previous katorga system. According to semi-official Soviet estimates, which did not become public until after the fall of the Soviet government in 1991, from 1929 to 1953 more than 14 million people passed through these camps and prisons, many of them in Siberia. Another seven to eight million people were internally deported to remote areas of the Soviet Union (including entire nationalities or ethnicities in several cases). Half a million (516,841) prisoners died in camps from 1941 to 1943 during World War II. At other periods, mortality was comparatively lower. The size, scope, and scale of the Gulag slave-labour camps remain subjects of much research and debate. Many Gulag camps operated in extremely remote areas of northeastern Siberia. The best-known clusters included Sevvostlag (the North-East Camps) along the Kolyma and Norillag near Norilsk, where 69,000 prisoners lived in 1952. Major industrial cities of northern Siberia, such as Norilsk and Magadan, developed from camps built by prisoners and run by former prisoners. After the Soviet collapse in 1991, Siberia faced severe economic decline during Russia's transition to a market economy, characterized by hyperinflation, industrial collapse, and resource privatization. While the idea of a Siberian Republic for more regional autonomy was discussed and a Siberian Agreement was formed in the 1990s, the region remained consolidated under Russian federal authority. Economic shifts led to increased resource-based specialization and a decline in the population, particularly in the Russian Arctic, as the previous focus on industrial settlements was largely abandoned. On 2 December 2019, the 'Power of Siberia' gas pipeline started functioning. The project was started in 2014 to supply natural gas from Siberia to China. Geography Siberia spans an area of 13.1 million square kilometres (5,100,000 mi2), covering most of Russia's total territory and almost 9% of Earth's land surface (148,940,000 km2, 57,510,000 sq mi). It geographically falls in Asia but is culturally and politically considered European, since it is a part of Russia. Major geographical zones include the West Siberian Plain and the Central Siberian Plateau. Eastern and central Sakha comprises numerous north–south mountain ranges of various ages. These mountains rise to almost 3,000 metres (9,800 ft), but above a few hundred metres they are almost completely devoid of vegetation. The Verkhoyansk Range was extensively glaciated in the Pleistocene, but the climate was too dry for glaciation to extend to low elevations. At these low elevations are numerous valleys, many of them deep and covered with larch forest, except in the extreme north where the tundra dominates. Soils are mainly turbels (a type of gelisol). The active layer tends to be less than one metre deep, except near rivers. The highest point is the active volcano Klyuchevskaya Sopka, on the Kamchatka Peninsula. Its peak reaches 4,750 metres (15,580 ft). The Ukok Plateau is a UNESCO World Heritage Site. The West Siberian Plain, consisting mostly of Cenozoic alluvial deposits, is somewhat flat. In the mid-Pleistocene, many deposits on this plain resulted from ice dams which produced a large glacial lake. This mid- to late-Pleistocene lake blocked the northward flow of the Ob and Yenisey rivers, resulting in a redirection southwest into the Caspian and Aral seas via the Turgai Valley. The area is very swampy, and soils are mostly peaty histosols and, in the treeless northern part, histels. In the south of the plain, where permafrost is largely absent, rich grasslands that are an extension of the Kazakh Steppe formed the original vegetation, most of which is no longer visible.[why?] The Central Siberian Plateau is an ancient craton (sometimes named Angaraland) that formed an independent continent before the Permian. It is exceptionally rich in minerals, containing large deposits of gold, diamonds, and ores of manganese, lead, zinc, nickel, cobalt, and molybdenum. Much of the area includes the Siberian Traps—a large igneous province. A massive eruptive period approximately coincided with the Permian–Triassic extinction event; the volcanic event is one of the largest known volcanic eruptions in Earth's history. Only the extreme northwest was glaciated during the Quaternary but almost all is under exceptionally deep permafrost, and the only tree that can thrive, despite the warm summers, is the deciduous Siberian Larch (Larix sibirica) with its very shallow roots. Outside the extreme northwest, the taiga is dominant, covering a significant fraction of the entirety of Siberia. Soils here are mainly turbels, giving way to spodosols where the active layer becomes thicker and the ice-content lower. The Lena-Tunguska petroleum province includes the Central Siberian platform (some authors refer to it as the "Eastern Siberian platform"), bounded on the northeast and east by the late Carboniferous through Jurassic Verkhoyansk fold belt, on the northwest by the Paleozoic Taymr fold belt, and on the southeast, south and southwest by the Middle Silurian to Middle Devonian Baykalian fold belt.: 228 A regional geologic reconnaissance study begun in 1932 and followed by surface and subsurface mapping revealed the Markova-Angara Arch (anticline). This led to the discovery of the Markovo Oil Field in 1962 with the Markovo–1 well, which produced from the early Cambrian Osa Horizon bar-sandstone at a depth of 2,156 metres (7,073 ft).: 243 The Sredne-Botuobin Gas Field was discovered in 1970, producing from the Osa and the Proterozoic Parfenovo Horizon.: 244 The Yaraktin Oil Field was discovered in 1971, producing from the Vendian Yaraktin Horizon at depths of up to 1,750 metres (5,740 ft), which lies below Permian to lower Jurassic basalt traps.: 244 The climate varies dramatically, but it typically has warm but short summers and long, extremely cold winters. On the north coast, north of the Arctic Circle, there is a very short (about one month long) summer. Almost all the population lives in the south, along the route of the Trans-Siberian Railway. The climate in this southernmost part is humid continental climate (Köppen Dfa/Dfb or Dwa/Dwb) with cold winters but fairly warm summers lasting at least four months. The annual average temperature is about 0.5 °C (32.9 °F). January averages about −20 °C (−4 °F) and July about +19 °C (66 °F), while daytime temperatures in summer typically exceed 20 °C (68 °F). With a reliable growing season, an abundance of sunshine and fertile chernozem soils, southern Siberia is acceptable for profitable agriculture, as was demonstrated in the early 20th century. Most of Siberia lies in a continental subarctic climate (Koppen Dfc, Dwc, or Dsc), with the annual average temperature about −5 °C (23 °F) and an average for January of −25 °C (−13 °F) and an average for July of +17 °C (63 °F), although this varies considerably, with a July average about 10 °C (50 °F) in the taiga–tundra ecotone. Business Insider lists Verkhoyansk and Oymyakon, in the Sakha Republic, as being in competition for the title of the "Pole of Cold:" the coldest inhabited point in the Northern Hemisphere. Oymyakon recorded a temperature of −67.7 °C (−89.9 °F) on 6 February 1933. Verkhoyansk, further north and further inland, recorded a temperature of −69.8 °C (−93.6 °F) for three consecutive nights: 5, 6 and 7 February 1933. Each town also frequently reaches 30 °C (86 °F) in the summer, giving them, and much of the rest of Russian Siberia, the world's greatest temperature variation between summer's highs and winter's lows, often well over 94–100+ °C (169–180+ °F) between the seasons.[failed verification] Southwesterly winds bring warm air from Central Asia and the Middle East. The climate in West Siberia (Omsk, or Novosibirsk) is several degrees warmer than in the East (Irkutsk, or Chita). But summer temperatures in other regions can reach +38 °C (100 °F). In general, Sakha is the coldest Siberian region, and the basin of the Yana has the lowest temperatures of all, with permafrost reaching 1,493 metres (4,898 ft). Nevertheless, Imperial Russian plans of settlement never viewed cold as an impediment. In the winter, southern Siberia sits near the center of the semi-permanent Siberian High, so winds are usually light in the winter. Precipitation is generally low, exceeding 500 millimetres (20 in) only in Kamchatka, where moist winds flow from the Sea of Okhotsk onto high mountains – producing the region's only major glaciers, though volcanic eruptions and low summer temperatures allow only limited forests to grow. Precipitation is high in most of Primorye in the extreme south, where monsoonal influences can produce quite heavy summer rainfall. According to Vasily Kryuchkov, approximately 31,000 square kilometers of the Russian Arctic has been subjected to severe environmental disturbance. Researchers, including Sergei Kirpotin at Tomsk State University and Judith Marquand at Oxford University, warn that Western Siberia has begun to thaw as a result of global warming. The frozen peat bogs in this region may hold billions of tons of methane gas which may be released into the atmosphere. Methane is a greenhouse gas 22 times more powerful than carbon dioxide. In 2008 a research expedition for the American Geophysical Union detected levels of methane up to 100 times above normal in the atmosphere above the Siberian Arctic, likely the result of methane clathrates being released through holes in a frozen "lid" of seabed permafrost around the outfall of the Lena and the area between the Laptev Sea and East Siberian Sea. Since 1988, experimentation at Pleistocene Park has proposed to restore the grasslands of prehistoric times by conducting research on the effects of large herbivores on permafrost, suggesting that animals, rather than climate, maintained the past ecosystem. The nature reserve park also conducts climatic research on the changes expected from the reintroduction of grazing animals or large herbivores, hypothesizing that a transition from tundra to grassland would lead to a net change in energy emission to absorption ratios. Fauna Flora Politics Borders and administrative division The term "Siberia" has both a long history and wide significance, and association. The understanding and association of "Siberia" have gradually changed during the ages. Historically, Siberia was defined as the whole part of Russia and North Kazakhstan to the east of Ural Mountains, including the Russian Far East. According to this definition, Siberia extended eastward from the Ural Mountains to the Pacific coast, and southward from the Arctic Ocean to the border of Central Asia and the national borders of both Mongolia and China. Soviet-era sources (Great Soviet Encyclopedia and others) and modern Russian ones usually define Siberia as a region extending eastward from the Ural Mountains to the watershed between Pacific and Arctic drainage basins, and southward from the Arctic Ocean to the hills of north-central Kazakhstan and the national borders of both Mongolia and China. By this definition, Siberia includes the federal subjects of the Siberian Federal District, and some of the Ural Federal District, as well as Sakha (Yakutia) Republic, which is a part of the Far Eastern Federal District. Geographically, this definition includes subdivisions of several other subjects of Urals and Far Eastern federal districts, but they are not included administratively. This definition excludes Sverdlovsk Oblast and Chelyabinsk Oblast, both of which are included in some wider definitions of Siberia. Other sources may use either a somewhat wider definition that states the Pacific coast, not the watershed, is the eastern boundary (thus including the whole Russian Far East), as well as all Northern Kazakhstan is its subregion in the south-west or a somewhat narrower one that limits Siberia to the Siberian Federal District (thus excluding all subjects of other districts). In Russian, 'Siberia' is commonly used as a substitute for the name of the federal district by those who live in the district itself, but less commonly used to denote the federal district by people residing outside of it. Due to the different interpretations of Siberia, starting from Tyumen, to Chita, the territory generally defined as 'Siberia', some people will define themselves as 'Siberian', while others not. A number of factors in recent years, including the fomenting of Siberian separatism, have made the definition of the territory of Siberia a potentially controversial subject. In the eastern extent of Siberia there are territories which are not clearly defined as either Siberia or the Far East, making the question of "what is Siberia?" one with no clear answer, and what is a "Siberian", one of self-identification. The most populous city of Siberia, as well as the third most populous city of Russia, is Novosibirsk. Present-day Novosibirsk is an important business, science, manufacturing and cultural center of the Asian part of Russia. Omsk played an important role in the Russian Civil War serving as a provisional Russian capital, as well in the expansion into and governing of Central Asia. In addition to its cultural status, it has become a major oil-refining, education, transport and agriculture hub. Other historic cities of Siberia include Tobolsk (the first capital and the only kremlin in Siberia), Tomsk (formerly a wealthy merchant's town) and Irkutsk (former seat of Eastern Siberia's governor general, near lake Baikal). Other major cities include Barnaul, Kemerovo, Krasnoyarsk, Novokuznetsk, Tyumen. Wider definitions of geographic Siberia also include the cities of Chelyabinsk and Yekaterinburg in the Urals; Khabarovsk and Vladivostok in the Russian Far East; and even Petropavlovsk in Kazakhstan and Harbin in China. Economy Novosibirsk is the most important city for the Siberian economy; with an extra boost since 2000 when it was designated a regional center for the executive bureaucracy (Siberian Federal District). Russia's largest oil refinery is the Omsk Refinery. Siberia is extraordinarily rich in minerals, containing ores of almost all economically valuable metals. It has some of the world's largest deposits of nickel, gold, lead, coal, molybdenum, gypsum, diamonds, diopside, silver and zinc, as well as extensive unexploited resources of oil and natural gas. Around 70% of Russia's developed oil fields are in the Khanty-Mansiysk region. Russia contains about 40% of the world's known resources of nickel at the Norilsk deposit in Siberia. Norilsk Nickel is the world's largest nickel and palladium producer. Siberian agriculture is severely restricted by the short growing season of most of the region. However, in the southwest where soils consist of fertile black earths and the climate is a little more moderate, there is extensive cropping of wheat, barley, rye and potatoes, along with the grazing of large numbers of sheep and cattle. Elsewhere food production, owing to the poor fertility of the podzolic soils and the extremely short growing seasons, is restricted to the herding of reindeer in the tundra—which has been practiced by natives for over 10,000 years.[citation needed] Siberia has the world's largest forests. Timber remains an important source of revenue, even though many forests in the east have been logged much more rapidly than they are able to recover. The Sea of Okhotsk is one of the two or three richest fisheries in the world owing to its cold currents and very large tidal ranges, and thus Siberia produces over 10% of the world's annual fish catch, although fishing has declined somewhat since the collapse of the USSR in 1991. Reported in 2009, the development of renewable energy in Russia is held back by the lack of a conducive government policy framework,[needs update] As of 2011[update], Siberia offers special opportunities for off-grid renewable energy developments. Remote parts of Siberia are too costly to connect to central electricity and gas grids and have therefore historically been supplied with costly diesel, sometimes flown in by helicopter. In such cases renewable energy is often cheaper. Sport Russia's third most popular sport, bandy, is important in Siberia. In the 2015–16 Russian Bandy Super League season Yenisey from Krasnoyarsk became champions for the third year in a row by beating Baykal-Energiya from Irkutsk in the final. Two or three more teams (depending on the definition of Siberia) play in the Super League, the 2016–17 champions SKA-Neftyanik from Khabarovsk as well as Kuzbass from Kemerovo and Sibselmash from Novosibirsk. In 2007 Kemerovo got Russia's first indoor arena specifically built for bandy. Now Khabarovsk has the world's largest indoor arena specifically built for bandy, Arena Yerofey. It was venue for Division A of the 2018 World Championship. In time for the 2020 World Championship, an indoor arena will be ready for use in Irkutsk. That one will also have a speed skating oval. Krasnoyarsk is one of the centres of rugby in Russia, with 2 of the largest clubs in the country, STM Enisei and Krasny Yar, are both based in the city. The Yenisey Krasnoyarsk basketball team has played in the VTB United League since 2011–12. The 2019 Winter Universiade was hosted by Krasnoyarsk. Demographics According to the Russian Census of 2010, the Siberian and Far Eastern Federal Districts, together have a population of about 25.6 million. Tyumen and Kurgan Oblasts, which are geographically in Siberia but administratively part of the Urals Federal District, together have a population of about 4.3 million. Thus, the whole region of Siberia (in the broadest usage of the term) is home to approximately 30 million people. It has a population density of about three people per square kilometre. The largest ethnic group in Siberia is Slavic-origin Russians, including their sub-ethnic group Siberians, and russified Ukrainians. Slavic and other Indo-European ethnicities make up the vast majority (over 85%) of the Siberian population. There are also other groups of indigenous Siberian and non-indigenous ethnic origin. A minority of the current population are descendants of Mongol or Turkic people (mainly Buryats, Yakuts, Tuvans, Altai and Khakas) or northern indigenous people. Slavic-origin Russians outnumber all of the indigenous peoples combined, except in the Republics of Tuva and Sakha. According to the 2002 census there are 500,000 Tatars in Siberia, but of these, 300,000 are Volga Tatars who also settled in Siberia during periods of colonization and are thus also non-indigenous Siberians, in contrast to the 200,000 Siberian Tatars which are indigenous to Siberia. Of the indigenous Siberians, the Mongol-speaking Buryats, numbering approximately 500,000, are the most numerous group in Siberia, and they are mainly concentrated in their homeland, the Buryat Republic. According to the 2010 census there were 478,085 indigenous Turkic-speaking Yakuts. Other ethnic groups indigenous to Siberia include Kets, Evenks, Chukchis, Koryaks, Yupiks, and Yukaghirs. About 70% of Siberia's people live in cities, mainly in apartments. Many people also live in rural areas, in simple, spacious, log houses. Religion There are a variety of beliefs throughout Siberia, including Orthodox Christianity, other denominations of Christianity, Tibetan Buddhism and Islam. The Siberian Federal District has an estimated 250,000 Muslims. An estimated 70,000 Jews live in Siberia, some in the Jewish Autonomous Region. The predominant religious group is the Russian Orthodox Church. Tradition regards Siberia the archetypal home of shamanism, and polytheism is popular. These native sacred practices are considered by the tribes to be very ancient. There are records of Siberian tribal healing practices dating back to the 13th century. The vast territory of Siberia has many different local traditions of gods. These include: Ak Ana, Anapel, Bugady Musun, Kara Khan, Khaltesh-Anki, Kini'je, Ku'urkil, Nga, Nu'tenut, Num-Torum, Pon, Pugu, Todote, Toko'yoto, Tomam, Xaya Iccita and Zonget. Places with sacred areas include Olkhon, an island in Lake Baikal. Transport Many cities in northern Siberia, such as Petropavlovsk-Kamchatsky, cannot be reached by road, as there are virtually none connecting from other major cities in Russia or Asia. Siberia can be reached through the Trans-Siberian Railway, which operates from Moscow in the west to Vladivostok in the east. Cities that are located far from the railway are reached by air or by the separate Baikal–Amur Railway. Culture Stroganina is a raw fish dish of the indigenous people of northern Arctic Siberia made from raw, thin, long-sliced frozen fish. It is a popular dish amongst native Siberians. Siberia is known for its pelmeni dumpling; in the winter, the dumplings are traditionally frozen and stored outdoors. There are various berry, nut and mushroom dishes making use of the riches of abundant nature. See also References Bibliography |
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[SOURCE: https://en.wikipedia.org/wiki/Fj%C3%B6lnir_(programming_language)] | [TOKENS: 208] |
Contents Fjölnir (programming language) Fjölnir (also Fjolnir or Fjoelnir) is a programming language developed by professor Snorri Agnarsson of computer science at Háskóli Íslands (University of Iceland) that was mostly used in the 1980s. The source files usually have the extension fjo or sma. Features Fjölnir is based on the concept of representing programs as trees, and packages by substitutions on trees using algebraic operators. For example, in the Hello World example below, "GRUNNUR" is a package, the block of code between braces is a package, and * is an operator that substitutes names in one package with elements from another. In this case, skrifastreng (which writes a string to the standard output) is imported from "GRUNNUR". Code examples External links References This programming-language-related article is a stub. You can help Wikipedia by adding missing information. |
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[SOURCE: https://github.com/resources/articles?topic=software-development] | [TOKENS: 699] |
Navigation Menu Search code, repositories, users, issues, pull requests... Provide feedback We read every piece of feedback, and take your input very seriously. Saved searches Use saved searches to filter your results more quickly To see all available qualifiers, see our documentation. GitHub Articles Filters (1) Topic Learn how software architecture helps developers build scalable, efficient systems using best practices, key components, and common styles and patterns. Learn how software architecture helps developers build scalable, efficient systems using best practices, key components, and common styles and patterns. Open source AI offers more control, clarity, and room to build the way you want. Open source AI offers more control, clarity, and room to build the way you want. Prompt engineering is the practice of crafting effective instructions that guide AI models to produce accurate, useful results. Prompt engineering is the practice of crafting effective instructions that guide AI models to produce accurate, useful results. Uncover how IDEs help streamline software development and accelerate software delivery. Uncover how IDEs help streamline software development and accelerate software delivery. Learn how version control systems and software help track changes, support collaboration, and ensure code integrity throughout the development process. Learn how version control systems and software help track changes, support collaboration, and ensure code integrity throughout the development process. Understand the impact of technical debt on software development. Learn how to manage and mitigate technical debt for long-term code quality and maintainability. Understand the impact of technical debt on software development. Learn how to manage and mitigate technical debt for long-term code quality and maintainability. Software testing is the systematic process of evaluating and verifying software applications to ensure they function correctly and meet specific requirements. Software testing is the systematic process of evaluating and verifying software applications to ensure they function correctly and meet specific requirements. Software engineering is the job of designing, developing, testing, and maintaining software applications and systems. Software engineering is the job of designing, developing, testing, and maintaining software applications and systems. Explore the world of software development in this comprehensive guide for beginners. Discover what software development is and why it matters, delve into key concepts, uncover the crucial steps in the development process, and learn how software shapes industries and technologies. Explore the world of software development in this comprehensive guide for beginners. Discover what software development is and why it matters, delve into key concepts, uncover the crucial steps in the development process, and learn how software shapes industries and technologies. Building great software is a big challenge, and development teams rely on the software development lifecycle (SDLC) to help them succeed. Building great software is a big challenge, and development teams rely on the software development lifecycle (SDLC) to help them succeed. Learn what platform engineering is and how it empowers developers by creating internal developer platforms, improving workflows, and reducing operational bottlenecks. Explore the benefits for developers and IT managers alike. Learn what platform engineering is and how it empowers developers by creating internal developer platforms, improving workflows, and reducing operational bottlenecks. Explore the benefits for developers and IT managers alike. Open source software (OSS) refers to software that features freely available source code, which users may view, modify, adopt, and share for both commercial and noncommercial purposes. Open source software (OSS) refers to software that features freely available source code, which users may view, modify, adopt, and share for both commercial and noncommercial purposes. Site-wide Links Get tips, technical guides, and best practices. Twice a month. |
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[SOURCE: https://en.wikipedia.org/wiki/Flavors_(programming_language)] | [TOKENS: 179] |
Contents Flavors (programming language) Flavors is an early object-oriented extension to Lisp developed by Howard Cannon at the MIT Artificial Intelligence Laboratory for the Lisp machine and its programming language Lisp Machine Lisp. It is notable as the first programming language to include mixins. Symbolics used it for its Lisp machines, and eventually developed it into New Flavors; both the original and new Flavors were message-passing OO models. It was hugely influential in the development of the Common Lisp Object System (CLOS). Implementations of Flavors are also available for Common Lisp. New Flavors replaced message sending with calling generic functions. Flavors offers :before and :after daemons with the default method combination (called :daemon). Flavors and CLOS features comparison Flavors offers a few features not found in CLOS: CLOS offers the following features not found in Flavors: Terminology References Further reading |
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[SOURCE: https://en.wikipedia.org/wiki/Flix_(programming_language)] | [TOKENS: 2548] |
Contents Flix (programming language) Flix is a functional, imperative, and logic programming language developed at Aarhus University, with funding from the Independent Research Fund Denmark, and by a community of open source contributors. The Flix language supports algebraic data types, pattern matching, parametric polymorphism, currying, higher-order functions, extensible records, channel and process-based concurrency, and tail call elimination. Two notable features of Flix are its type and effect system and its support for first-class Datalog constraints. The Flix type and effect system supports Hindley-Milner-style type inference. The system separates pure and impure code: if an expression is typed as pure then it cannot produce an effect at run-time. Higher-order functions can enforce that they are given pure (or impure) function arguments. The type and effect system supports effect polymorphism which means that the effect of a higher-order function may depend on the effect(s) of its argument(s). Flix supports Datalog programs as first-class values. A Datalog program value, i.e. a collection of Datalog facts and rules, can be passed to and returned from functions, stored in data structures, and composed with other Datalog program values. The minimal model of a Datalog program value can be computed and is itself a Datalog program value. In this way, Flix can be viewed as a meta programming language for Datalog. Flix supports stratified negation and the Flix compiler ensures stratification at compile-time. Flix also supports an enriched form of Datalog constraints where predicates are given lattice semantics. Overview Flix is a programming language in the ML-family of languages. Its type and effect system is based on Hindley-Milner with several extensions, including row polymorphism and Boolean unification. The syntax of Flix is inspired by Scala and uses short keywords and curly braces. The concurrency model of Flix is inspired by Go and based on channels and processes. A process is a light-weight thread that does not share (mutable) memory with another process. Processes communicate over channels which are bounded or unbounded queues of immutable messages. While many programming languages support a mixture of functional and imperative programming, the Flix type and effect system tracks the purity of every expression making it possible to write parts of a Flix program in a purely functional style with purity enforced by the effect system. Flix programs compile to JVM bytecode and are executable on the Java Virtual Machine (JVM). The Flix compiler performs whole program compilation, eliminates polymorphism via monomorphization, and uses tree shaking to remove unreachable code. Monomorphization avoids boxing of primitive values at the cost of longer compilation times and larger executable binaries. Flix has some support for interoperability with programs written in Java. Flix supports tail call elimination which ensures that function calls in tail position never consume stack space and hence cannot cause the call stack to overflow. Since the JVM instruction set lacks explicit support for tail calls, such calls are emulated using a form of reusable stack frames. Support for tail call elimination is important since all iteration in Flix is expressed through recursion. The Flix compiler disallows most forms of unused or redundant code, including: unused local variables, unused functions, unused formal parameters, unused type parameters, and unused type declarations, such unused constructs are reported as compiler errors. Variable shadowing is also disallowed. The stated rationale is that unused or redundant code is often correlated with erroneous code A Visual Studio Code extension for Flix is available. The extension is based on the Language Server Protocol, a common interface between IDEs and compilers being developed by Microsoft. Flix is open source software available under the Apache 2.0 License. Examples The following program prints "Hello World!" when compiled and executed: The type and effect signature of the main function specifies that it has no parameters, returns a value of type Unit, and that the function has the IO effect, i.e. is impure. The main function is impure because it invokes printLine which is impure. The following program fragment declares an algebraic data type (ADT) named Shape: The ADT has three constructors: Circle, Square, and Rectangle. The following program fragment uses pattern matching to destruct a Shape value: The following program fragment defines a higher-order function named twice that when given a function f from Int to Int returns a function that applies f to its input two times: We can use the function twice as follows: Here the call to twice(x -> x + 1) returns a function that will increment its argument two times. Thus the result of the whole expression is 0 + 1 + 1 = 2. The following program fragment illustrates a polymorphic function that maps a function f: a -> b over a list of elements of type a returning a list of elements of type b: The map function recursively traverses the list l and applies f to each element constructing a new list. Flix supports type parameter elision hence it is not required that the type parameters a and b are explicitly introduced. The following program fragment shows how to construct a record with two fields x and y: Flix uses row polymorphism to type records. The sum function below takes a record that has x and y fields (and possibly other fields) and returns the sum of the two fields: The following are all valid calls to the sum function: Notable features The Flix type and effect system separates pure and impure expressions. A pure expression is guaranteed to be referentially transparent. A pure function always returns the same value when given the same argument(s) and cannot have any (observable) side-effects. For example, the following expression is of type Int32 and has the empty effect set {}, i.e. it is pure: whereas the following expression has the IO effect, i.e. is impure: A higher-order function can specify that a function argument must be pure, impure, or that it is effect polymorphic. For example, the definition of Set.exists requires that its function argument f is pure: The requirement that f must be pure ensures that implementation details do not leak. For example, since f is pure it cannot be used to determine in what order the elements of the set are traversed. If f was impure such details could leak, e.g. by passing a function that also prints the current element, revealing the internal element order inside the set. A higher-order function can also require that a function is impure. For example, the definition of List.foreach requires that its function argument f is impure: The requirement that f must be impure ensures that the code makes sense: It would be meaningless to call List.foreach with a pure function since it always returns Unit. The type and effect is sound, but not complete. That is, if a function is pure then it cannot cause an effect, whereas if a function is impure then it may, but not necessarily, cause an effect. For example, the following expression is impure even though it cannot produce an effect at run-time: A higher-order function can also be effect polymorphic: its effect(s) can depend on its argument(s). For example, the standard library definition of List.map is effect polymorphic: The List.map function takes a function f from elements of type a to b with effect e. The effect of the map function is itself e. Consequently, if List.map is invoked with a pure function then the entire expression is pure whereas if it is invoked with an impure function then the entire expression is impure. It is effect polymorphic. A higher-order function that takes multiple function arguments may combine their effects. For example, the standard library definition of forward function composition >> is pure if both its function arguments are pure: The type and effect signature can be understood as follows: The >> function takes two function arguments: f with effect e1 and g with effect e2. The effect of >> is effect polymorphic in the conjunction of e1 and e2. If both are pure then the overall expression is pure. The type and effect system allows arbitrary set expressions to control the purity of function arguments. For example, it is possible to express a higher-order function h that accepts two function arguments f and g where the effects of f are disjoint from those of g: If h is called with a function argument f which has the IO effect then g cannot have the IO effect. The type and effect system can be used to ensure that statement expressions are useful, i.e. that if an expression or function is evaluated and its result is discarded then it must have a side-effect. For example, compiling the program fragment below: causes a compiler error: because it is non-sensical to evaluate the pure expression List.map(x -> 2 * x, 1 :: 2 :: Nil) and then to discard its result. Most likely the programmer wanted to use the result (or alternatively the expression is redundant and could be deleted). Consequently, Flix rejects such programs. Flix supports Datalog programs as first-class values. A Datalog program is a logic program that consists of a collection of unordered facts and rules. Together, the facts and rules imply a minimal model, a unique solution to any Datalog program. In Flix, Datalog program values can be passed to and returned from functions, stored in data structures, composed with other Datalog program values, and solved. The solution to a Datalog program (the minimal model) is itself a Datalog program. Thus, it is possible to construct pipelines of Datalog programs where the solution, i.e. "output", of one Datalog program becomes the "input" to another Datalog program. The following edge facts define a graph: The following Datalog rules compute the transitive closure of the edge relation: The minimal model of the facts and rules is: In Flix, Datalog programs are values. The above program can be embedded in Flix as follows: The local variable f holds a Datalog program value that consists of the edge facts. Similarly, the local variable p is a Datalog program value that consists of the two rules. The f <+> p expression computes the composition (i.e. union) of the two Datalog programs f and p. The solve expression computes the minimal model of the combined Datalog program, returning the edge and path facts shown above. Since Datalog programs are first-class values, we can refactor the above program into several functions. For example: The un-directed closure of the graph can be computed by adding the rule: We can modify the closure function to take a Boolean argument that determines whether we want to compute the directed or un-directed closure: The Flix type system ensures that Datalog program values are well-typed. For example, the following program fragment does not type check: because in p1 the type of the Edge predicate is Edge(Int32, Int32) whereas in p2 it has type Edge(String, String). The Flix compiler rejects such programs as ill-typed. The Flix compiler ensures that every Datalog program value constructed at run-time is stratified. Stratification is important because it guarantees the existence of a unique minimal model in the presence of negation. Intuitively, a Datalog program is stratified if there is no recursion through negation, i.e. a predicate cannot depend negatively on itself. Given a Datalog program, a cycle detection algorithm can be used to determine if it is stratified. For example, the following Flix program contains an expression that cannot be stratified: because the last expression constructs a Datalog program value whose precedence graph contains a negative cycle: the Bachelor predicate negatively depends on the Husband predicate which in turn (positively) depends on the Bachelor predicate. The Flix compiler computes the precedence graph for every Datalog program valued expression and determines its stratification at compile-time. If an expression is not stratified, the program is rejected by the compiler. The stratification is sound, but conservative. For example, the following program is unfairly rejected: The type system conservatively assumes that both branches of the if expression can be taken and consequently infers that there may be a negative cycle between the A and B predicates. Thus the program is rejected. This is despite the fact that at run-time the main function always returns a stratified Datalog program value. Design philosophy Flix is designed around a collection of stated principles: The principles also list several programming language features that have been deliberately omitted. In particular, Flix lacks support for: References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Al-Sawalima] | [TOKENS: 476] |
Contents Al-Sawalima Al-Sawalima was a Palestinian Arab village in the Jaffa Subdistrict. It was depopulated during the 1947–1948 Civil War in Mandatory Palestine on March 30, 1948. It was located 11 km northeast of Jaffa, situated 2 km north of the al-'Awja River. History In 1051 AH/1641/2, the Bedouin tribe of al-Sawālima from around Jaffa attacked the villages of Subṭāra, Bayt Dajan, al-Sāfiriya, Jindās, Lydda and Yāzūr belonging to Waqf Haseki Sultan. In 1882 the PEF's Survey of Western Palestine noted at Khurbet es Sualimiyeh: “Traces of ruins only.“ Excavations revealed traces of Late Ottoman infant jar-burials, commonly associated with nomads or itinerant workers of Egyptian origins. In the 1922 census of Palestine conducted by the British Mandate authorities, Sawalmeh had a population of 70 Muslims, increasing in the 1931 census when Es-Sawalmeh had 429 Muslim inhabitants. In the 1945 statistics, the village had a population of 800 Muslims, while the total land area was 5,942 dunams, according to an official land and population survey. Of the land area, a total of 894 were used for growing citrus and banana, 191 were for plantations and irrigable land, 4,566 for cereals, while 291 dunams were classified as non-cultivable areas. Al-Sawalima had an elementary school for boys founded in 1946, with 31 students. Benny Morris gives "Fear of being caught up in the fighting" and "Influence of nearby town's fall" as reasons for why the village became depopulated on March 30, 1948. In 1992 the village site was described: "Cactuses grow on the village site. No identifiable traces of the former dwellings (tents or adobe houses) remain. Only the remnants of the one-room school are discernable. A highway runs past the north side of the site." References Bibliography External links |
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[SOURCE: https://en.wikipedia.org/wiki/Chukchi_people] | [TOKENS: 2103] |
Contents Chukchi people The Chukchi, or Chukchee (Chukot: ԓыгъоравэтԓьэт, о'равэтԓьэт, ḷygʺoravètḷʹèt, o'ravètḷʹèt), are a Siberian ethnic group native to the Chukchi Peninsula, the shores of the Chukchi Sea and the Bering Sea region of the Arctic Ocean all within modern Russia. They speak the Chukchi language. The Chukchi originated from the people living around the Okhotsk Sea. According to several studies on genomic research conducted from 2014 to 2018, the Chukchi are the closest Asian relatives of the Indigenous peoples of the Americas, as such they are descendants of the settlers of Beringia who remained on the Russian side when the sea levels rose. The majority of Chukchi reside within Chukotka Autonomous Okrug, but some also reside in the neighboring Sakha Republic to the west, Magadan Oblast to the southwest, and Kamchatka Krai to the south. Some Chukchi also reside in other parts of Russia, as well as in Europe and North America. The total number of Chukchi in the world slightly exceeds 16,000. Culture The Chukchi are traditionally divided into the Maritime Chukchi, who had settled homes on the coast and lived primarily from sea mammal hunting, and the Reindeer Chukchi, who lived as nomads in the inland tundra region, migrating seasonally with their herds of reindeer. The Russian name "Chukchi" is derived from the Chukchi word Chauchu ("rich in reindeer"), which was used by the 'Reindeer Chukchi' to distinguish themselves from the 'Maritime Chukchi,' called Anqallyt ("the sea people"). Their name for a member of the Chukchi ethnic group as a whole is Luoravetlan (literally 'genuine person'). The anthropologist Marshall Sahlins called the Chukchi "tribes without rulers". They often lacked formal political structures, but had a formal cosmic hierarchy. One of the Chukchi's forms of folk art is sculpture and carving on bones and walrus tusks but only men engage in this. Common traditional themes of these arts are landscapes, hunting scenes, and animals. The women are skilled seamstresses. The traditional dress for both genders is made of skins and fur, decorated with beads and embroidery on holidays and special occasions. Men wear loose shirts and trousers made of the same material at important traditional events. In Chukchi religion, every object, whether animate or inanimate, is assigned a spirit. This spirit can be either harmful or benevolent. Some of Chukchi myths reveal a dualistic cosmology. A Chukchi shaman once explained to the ethnographer Vladimir Bogoraz that "The lamp walks around. The walls of the house have voices of their own. ... Even the shadows on the wall constitute definite tribes and have their own country, where they live in huts and subsist by hunting." During Chukchi rituals, shamans fall into trances (sometimes with the aid of hallucinogenic mushrooms), communicate with spirits, allow the spirits to speak through them, predict the future and cast spells. Early Russian ethnographers observed that Chukchi shamans were said to be called by spirits, dreams, or omens, and were believed to be capable of flight, exorcism, and healing. Some shamans were called by mystical forces to engage in a form of ritualized homosexual relations with other men. This ritual typically involved a gender change through a religious ceremony that, it was believed, transformed his genitalia into that of a female. After the change, he might dress in women's clothing and behave in feminine ways. He was then believed to "lose" masculine traits like hunting skill, and instead take on "feminine" traits, like healing and nurturing. Some of these shamans would take male lovers, and could even marry other men, and the shaman would take on a "wifely" role. Subsistence In prehistoric times, the Chukchi engaged in nomadic hunter gatherer modes of existence. In current times, there continue to be some elements of subsistence hunting, including that of polar bears, seals, walruses, whales, and reindeer. There are some differences between the traditional lifestyles of the coastal and inland Chukchi. The coastal Chukchi were largely settled fishers and hunters, mainly of sea mammals. The inland Chukchi were partial reindeer herders. Beginning in the 1920s, the Soviets organized the economic activities of both coastal and inland Chukchi and eventually established 28 collectively run, state-owned enterprises in Chukotka. All of these were based on reindeer herding, with the addition of sea mammal hunting and walrus ivory carving in the coastal areas. Chukchi were educated in Soviet schools and today are almost 100% literate and fluent in the Russian language. Only a portion of them today work directly in reindeer herding or sea mammal hunting, and continue to live a nomadic lifestyle in yaranga tents. Relations with Russians The Chukchi participated in endemic warfare against neighboring tribes, especially the Koryaks. Russians first began contacting the Chukchi when they reached the Kolyma (1643) and the Anadyr (1649). The route from Nizhnekolymsk to the fort at Anadyrsk along the southwest of the main Chukchi area became a major trade route. The overland journey from Yakutsk to Anadyrsk took about six months.[citation needed] The Chukchi were generally ignored for the next fifty years because they were warlike and did not provide furs or other valuable commodities to tax. Armed skirmishes flared up around 1700 when the Russians began operating in the Kamchatka Peninsula and needed to protect their communications from the Chukchi and Koryak. The first attempt to conquer them was made in 1701. Other expeditions were sent out in 1708, 1709 and 1711 with considerable bloodshed but little success and unable to eliminate the local population on the large territory. War was renewed in 1729, when the Chukchi defeated an expedition from Okhotsk and killed its commander. Command passed to Major Dmitry Pavlutsky, who adopted very destructive tactics, burning, driving off reindeer, killing men and capturing women and children. In 1742, the government at Saint Petersburg ordered another war in which the Chukchi and Koryak were to be "totally extirpated". The war (1744–47) was conducted with similar brutality and ended when Pavlutsky was killed in March 1747. It is said that the Chukchi kept his head as a trophy for several years. The Russians waged war again in the 1750s, but some Chukchi did survive these extermination plans in the very far northeast. In 1762, when Catherine the Great was crowned, Saint Petersburg adopted a different policy. Maintaining the fort at Anadyrsk had cost some 1,380,000 rubles, but the area had returned only 29,150 rubles in taxes, so the government abandoned Anadyrsk in 1764. The Chukchi, no longer attacked by the Russian Empire, began to trade peacefully with the Russians. From 1788, they participated in an annual trade fair on the lower Kolyma. Another was established in 1775 on the Angarka, a tributary of the Bolshoy Anyuy. This trade declined in the late 19th century when American whalers and others began landing goods on the coast. The first Christian missions from the Eastern Orthodox Church entered Chukchi territory some time after 1815. The strategy worked, and trade flourished between the Cossacks and the Chukchi. As the annual trade fairs where goods were exchanged continued, a common language between the two peoples was spoken. The Native people, however, never paid yasak (a fur tribute), and their status as subjects was little more than a formality. The formal annexation of the Chukotka Peninsula did not happen until much later, during the time of the Soviet Union. Apart from four Orthodox schools, there were no schools in the Chukchi land until the late 1920s. In 1926, there were 72 literate Chukchis. The Soviets introduced a Latin alphabet in 1932 to transcribe their language, replacing it with Cyrillic in 1937. In 1934, 71% of the Chukchis were nomadic. In 1941, 90% of the reindeer were still privately owned. So-called kulaks roamed with their private herds up into the 1950s. Population estimates from Forsyth: Chukchi jokes are a staple of Soviet humor, where they are depicted as primitive, uncivilized, and simple-minded, but clever in their own way. After 1990 and the fall of the Soviet Union, there was a major exodus of Russians from the area because of the underfunding of the local industry.[citation needed] After the collapse of the Soviet Union, the state-run farms were reorganized and nominally privatized. This process was ultimately destructive to the village-based economy in Chukotka. The region has still not fully recovered. Many rural Chukchi, as well as Russians in Chukotka's villages, have survived in recent years[when?] only with the help of direct humanitarian aid. Some Chukchi have attained university degrees, becoming poets, writers, politicians, teachers and doctors. In the context of the Russian invasion of Ukraine since 2022, the Chukchis have been reported as one of Russia's ethnic minority groups suffering from a disproportionally large casualty rate among Russian forces. References Further reading External links |
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