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Léon Lalanne
Léon Louis Lalanne (; real surname: Chrétien-Lalanne; 3 July 1811 – 12 March 1892) was a French engineer and politician. Life Lalanne was born in Paris on 3 July 1811, as Léon Louis Chrétien, the son of François Julien Léon Chrétien, a physician, and his wife Aurore Marie Damaris Langlois; his surname became Lalanne-Chrétien in 1820, Lalanne being the unmarried name of his father's first wife, and he dropped the Chrétien for practical use. He was the brother of the historian Ludovic Lalanne (1815–1898). Lalanne studied at the Lycée Louis-le-Grand, where he was a classmate of Évariste Galois. From 1829 at the École Polytechnique, he went on to the École des ponts et chaussées in 1831. After that, he was a civil engineer, working mostly in northern France from 1832 to 1843. In 1837 he went on the group visit to Southern Russia organized by Anatoly Demidov (the future Count Demidov and 1st Prince of San Donato). From 1839 he was working also with Jean-Claude-Répu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Léon Lalanne
Léon Louis Lalanne (; real surname: Chrétien-Lalanne; 3 July 1811 – 12 March 1892) was a French engineer and politician. Life Lalanne was born in Paris on 3 July 1811, as Léon Louis Chrétien, the son of François Julien Léon Chrétien, a physician, and his wife Aurore Marie Damaris Langlois; his surname became Lalanne-Chrétien in 1820, Lalanne being the unmarried name of his father's first wife, and he dropped the Chrétien for practical use. He was the brother of the historian Ludovic Lalanne (1815–1898). Lalanne studied at the Lycée Louis-le-Grand, where he was a classmate of Évariste Galois. From 1829 at the École Polytechnique, he went on to the École des ponts et chaussées in 1831. After that, he was a civil engineer, working mostly in northern France from 1832 to 1843. In 1837 he went on the group visit to Southern Russia organized by Anatoly Demidov (the future Count Demidov and 1st Prince of San Donato). From 1839 he was working also with Jean-Claude-Répu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treaty Of Berlin (1878)
The Treaty of Berlin (formally the Treaty between Austria-Hungary, France, Germany, Great Britain and Ireland, Italy, Russia, and the Ottoman Empire for the Settlement of Affairs in the East) was signed on 13 July 1878. In the aftermath of the Russian victory against the Ottoman Empire in the Russo-Turkish War of 1877–1878, the major powers restructured the map of the Balkan region. They reversed some of the extreme gains claimed by Russia in the preliminary Treaty of San Stefano, but the Ottomans lost their major holdings in Europe. It was one of three major peace agreements in the period after the 1815 Congress of Vienna. It was the final act of the Congress of Berlin (13 June – 13 July 1878) and included Great Britain and Ireland, Austria-Hungary, France, Germany, Italy, Russia and the Ottoman Empire. Chancellor of Germany Otto von Bismarck was the chairman and dominant personality. The most important task of the Congress was to decide the fate of Bulgaria, but Bulgaria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cubic Equation
In algebra, a cubic equation in one variable is an equation of the form :ax^3+bx^2+cx+d=0 in which is nonzero. The solutions of this equation are called roots of the cubic function defined by the left-hand side of the equation. If all of the coefficients , , , and of the cubic equation are real numbers, then it has at least one real root (this is true for all odd-degree polynomial functions). All of the roots of the cubic equation can be found by the following means: * algebraically, that is, they can be expressed by a cubic formula involving the four coefficients, the four basic arithmetic operations and th roots (radicals). (This is also true of quadratic (second-degree) and quartic (fourth-degree) equations, but not of higher-degree equations, by the Abel–Ruffini theorem.) * trigonometrically * numerical approximations of the roots can be found using root-finding algorithms such as Newton's method. The coefficients do not need to be real numbers. Much of what is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projective Transformation
In projective geometry, a homography is an isomorphism of projective spaces, induced by an isomorphism of the vector spaces from which the projective spaces derive. It is a bijection that maps lines to lines, and thus a collineation. In general, some collineations are not homographies, but the fundamental theorem of projective geometry asserts that is not so in the case of real projective spaces of dimension at least two. Synonyms include projectivity, projective transformation, and projective collineation. Historically, homographies (and projective spaces) have been introduced to study perspective and projections in Euclidean geometry, and the term ''homography'', which, etymologically, roughly means "similar drawing", dates from this time. At the end of the 19th century, formal definitions of projective spaces were introduced, which differed from extending Euclidean or affine spaces by adding points at infinity. The term "projective transformation" originated in these abstract ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anamorphosis
Anamorphosis is a distorted projection requiring the viewer to occupy a specific vantage point, use special devices, or both to view a recognizable image. It is used in painting, photography, sculpture and installation, toys, and film special effects. The word is derived from the Greek prefix ''ana-'', meaning "back" or "again", and the word ''morphe'', meaning "shape" or "form". Extreme anamorphosis has been used by artists to disguise caricatures, erotic and scatological scenes, and other furtive images from a casual spectator, while revealing an undistorted image to the knowledgeable viewer. Types of projection There are two main types of anamorphosis: ''perspective'' (oblique) and ''mirror'' (catoptric). More complex anamorphoses can be devised using distorted lenses, mirrors, or other optical transformations. An oblique anamorphism forms an affine transformation of the subject. Early examples of Perspective (graphical), perspectival anamorphosis date to the Renaissance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slide Rule
The slide rule is a mechanical analog computer which is used primarily for multiplication and division, and for functions such as exponents, roots, logarithms, and trigonometry. It is not typically designed for addition or subtraction, which is usually performed using other methods. Maximum accuracy for standard linear slide rules is about three decimal significant digits, while scientific notation is used to keep track of the order of magnitude of results. Slide rules exist in a diverse range of styles and generally appear in a linear, circular or cylindrical form, with slide rule scales inscribed with standardized Graduation (instrument), graduated markings. Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in specialized calculations particular to those fields. The slide rule is closely related to nomograms used for application-specific computations. Though similar in name and appearance to a standard ruler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomogram
A nomogram (from Greek , "law" and , "line"), also called a nomograph, alignment chart, or abac, is a graphical calculating device, a two-dimensional diagram designed to allow the approximate graphical computation of a mathematical function. The field of nomography was invented in 1884 by the French engineer Philbert Maurice d'Ocagne (1862–1938) and used extensively for many years to provide engineers with fast graphical calculations of complicated formulas to a practical precision. Nomograms use a parallel coordinate system invented by d'Ocagne rather than standard Cartesian coordinates. A nomogram consists of a set of n scales, one for each variable in an equation. Knowing the values of n-1 variables, the value of the unknown variable can be found, or by fixing the values of some variables, the relationship between the unfixed ones can be studied. The result is obtained by laying a straightedge across the known values on the scales and reading the unknown value from where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philbert Maurice D'Ocagne
Philbert Maurice d'Ocagne (25 March 1862 – 23 September 1938) was a French engineer and mathematician. He founded the field of nomography, the graphic computation of algebraic equations, on charts which he called nomogram. Biography Philbert-Maurice Ocagne was born in Paris on 25 March 1862. He attended high school at the Lycée Fontanges school in Paris, and studied at Chaptal college. In 1877, he published his first mathematical work. In 1880, he entered the École Polytechnique. He published many articles on math. Starting in 1885, he served for six years as engineer, supporting waterworks projects in Rochefort and Cherbourg, then worked at Seine-et-Oise, at the residence of Pontoise. From 1882, he continued to published articles on mathematics in the French Academy of Sciences and major journals including '' Journal of the École Polytechnique'', ''Bulletin de la Société Mathématique de France'', ''Acta Mathematica'', '' Archiv der Mathematik und Physik'', and ''America ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walter Christaller
Walter Christaller (April 21, 1893 – March 9, 1969), was a German geographer whose principal contribution to the discipline is central place theory, first published in 1933. This groundbreaking theory was the foundation of the study of cities as systems of cities, rather than simple hierarchies or single entities. He was primarily concerned with the urban space and worked on the role of towns as geographic-economic units, besides analyzing the relationships between towns of the same region. Life Walter Christaller was born to Erdmann Gottreich and Helene Christaller, an author of Christian-themed children's novels at Berneck (today part of Altensteig in Germany. His paternal grandfather Johann Gottlieb Christaller was a linguist and a Christian missionary in West Africa. Before 1914, Christaller began studies in philosophy and political economics and subsequently served in the German Army during World War I. He was homeschooled and educated at the Universities of Heidelb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isopleth
A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional graph of the function f(x,y) parallel to the (x,y)-plane. More generally, a contour line for a function of two variables is a curve connecting points where the function has the same particular value. In cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes. The contour interval of a contour map is the difference in elevation between successive contour lines. The gradient of the function is always perpendicular to the contour lines. When the lines are close together the magnitude of the gradie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartography
Cartography (; from grc, χάρτης , "papyrus, sheet of paper, map"; and , "write") is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an imagined reality) can be modeled in ways that communicate spatial information effectively. The fundamental objectives of traditional cartography are to: * Set the map's agenda and select traits of the object to be mapped. This is the concern of map editing. Traits may be physical, such as roads or land masses, or may be abstract, such as toponyms or political boundaries. * Represent the terrain of the mapped object on flat media. This is the concern of map projections. * Eliminate characteristics of the mapped object that are not relevant to the map's purpose. This is the concern of generalization. * Reduce the complexity of the characteristics that will be mapped. This is also the concern of generalization. * Orchestrate the elements of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
