• Title/Summary/Keyword: Conics

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SOME CHARACTERIZATIONS OF CONICS AND HYPERSURFACES WITH CENTRALLY SYMMETRIC HYPERPLANE SECTIONS

  • Shin-Ok Bang;Dong Seo Kim;Dong-Soo Kim;Wonyong Kim
    • Communications of the Korean Mathematical Society
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    • v.39 no.1
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    • pp.211-221
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    • 2024
  • Parallel conics have interesting area and chord properties. In this paper, we study such properties of conics and conic hypersurfaces. First of all, we characterize conics in the plane with respect to the above mentioned properties. Finally, we establish some characterizations of hypersurfaces with centrally symmetric hyperplane sections.

Reinterpretation of the Biot's conjecture on conics (Biot의 원뿔곡선에 관한 conjecture의 재해석)

  • Kim, Hyang Sook;Park, Hye Kyung
    • East Asian mathematical journal
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    • v.36 no.4
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    • pp.455-474
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    • 2020
  • In this study, we investigate the latus rectum, one of the geometric measures of the conics, as one of the ways in which learners harmonize the geometric and algebraic approaches to conics from a pedagogical point of view. We also introduce the conical curve of Biot as presented in 'The Discourse on the Latus Rectum in conics(2013)' by Takeshi Sugimoto and reinterpret it for visualization and use as teaching material. Therefore, we expect that the importance of mathematical concepts will be recognized in conics and students can experience geometry learning that is explored in the school field and have a positive effect in developing the power to apply even in the context of applied problems.

The reinterpretation and visualization for methods of solving problem by Khayyam and Al-Kāshi for teaching the mathematical connection of algebra and geometry (대수와 기하의 수학적 연결성 지도를 위한 Khayyam과 Al-Kāshi의 문제 해결 방법 재조명 및 시각화)

  • Kim, Hyang Sook;Park, See Eun
    • East Asian mathematical journal
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    • v.37 no.4
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    • pp.401-426
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    • 2021
  • In order to propose ways to implement mathematical connection between algebra and geometry, this study reinterpreted and visualized the Khayyam's geometric method solving the cubic equations using two conic sections and the Al-Kāshi's method of constructing of angle trisection using a cubic equation. Khayyam's method is an example of a geometric solution to an algebraic problem, while Al-Kāshi's method is an example of an algebraic a solution to a geometric problem. The construction and property of conics were presented deductively by the theorem of "Stoicheia" and the Apollonius' symptoms contained in "Conics". In addition, I consider connections that emerged in the alternating process of algebra and geometry and present meaningful Implications for instruction method on mathematical connection.

CONICS IN QUINTIC DEL PEZZO VARIETIES

  • Kiryong Chung;Sanghyeon Lee
    • Journal of the Korean Mathematical Society
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    • v.61 no.2
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    • pp.357-375
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    • 2024
  • The smooth quintic del Pezzo variety Y is well-known to be obtained as a linear sections of the Grassmannian variety Gr(2, 5) under the Plücker embedding into ℙ9. Through a local computation, we show the Hilbert scheme of conics in Y for dimY ≥ 3 can be obtained from a certain Grassmannian bundle by a single blowing-up/down transformation.

Orthogonal projection of points in CAD/CAM applications: an overview

  • Ko, Kwanghee;Sakkalis, Takis
    • Journal of Computational Design and Engineering
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    • v.1 no.2
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    • pp.116-127
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    • 2014
  • This paper aims to review methods for computing orthogonal projection of points onto curves and surfaces, which are given in implicit or parametric form or as point clouds. Special emphasis is place on orthogonal projection onto conics along with reviews on orthogonal projection of points onto curves and surfaces in implicit and parametric form. Except for conics, computation methods are classified into two groups based on the core approaches: iterative and subdivision based. An extension of orthogonal projection of points to orthogonal projection of curves onto surfaces is briefly explored. Next, the discussion continues toward orthogonal projection of points onto point clouds, which spawns a different branch of algorithms in the context of orthogonal projection. The paper concludes with comments on guidance for an appropriate choice of methods for various applications.

A Study of Current Driven Electrostatic Instability on the Auroal Zone -Based on Particle Simulation Methods- (오로라 지역(Auroral Zone)에서의 전류에 의한 정전기적 불안정성 연구 -입자모의 실험방법을 중심으로-)

  • Kim, S.Y.;Okuda, H.
    • Journal of Astronomy and Space Sciences
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    • v.3 no.2
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    • pp.71-79
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    • 1986
  • According to recent satellite observations, strong ion transverse acceleration to the magnetic field(ion conics) has been known. The ion conics may be a result of electrostatic waves frequently observed on the auroral zone. Both linear and nonlinear theory of electrostatic instability driven by an electron current based on 1-dimensional particle simulation experiment have been considered. From the results of simulation strong ion transverse acceleration has been shown.

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Stereo Vision based on Planar Algebraic Curves (평면대수곡선을 기반으로 한 스테레오 비젼)

  • Ahn, Min-Ho;Lee, Chung-Nim
    • Journal of KIISE:Software and Applications
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    • v.27 no.1
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    • pp.50-61
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    • 2000
  • Recently the stereo vision based on conics has received much attention by many authors. Conics have many features such as their matrix expression, efficient correspondence checking, abundance of conical shapes in real world. Extensions to higher algebraic curves met with limited success. Although irreducible algebraic curves are rather rare in the real world, lines and conics are abundant whose products provide good examples of higher algebraic curves. We consider plane algebraic curves of an arbitrary degree $n{\geq}2$ with a fully calibrated stereo system. We present closed form solutions to both correspondence and reconstruction problems. Let $f_1,\;f_2,\;{\pi}$ be image curves and plane and $VC_P(g)$ the cone with generator (plane) curve g and vertex P. Then the relation $VC_{O1}(f_1)\;=\;VC_{O1}(VC_{O2}(f_2)\;∩\;{\pi})$ gives polynomial equations in the coefficient $d_1,\;d_2,\;d_3$ of the plane ${\pi}$. After some manipulations, we get an extremely simple polynomial equation in a single variable whose unique real positive root plays the key role. It is then followed by evaluating $O(n^2)$ polynomials of a single variable at the root. It is in contrast to the past works which usually involve a simultaneous system of multivariate polynomial equations. We checked our algorithm using synthetic as well as real world images.

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FREE AND NEARLY FREE CURVES FROM CONIC PENCILS

  • Dimca, Alexandru
    • Journal of the Korean Mathematical Society
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    • v.55 no.3
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    • pp.705-717
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    • 2018
  • We construct some infinite series of free and nearly free curves using pencils of conics with a base locus of cardinality at most two. These curves have an interesting topology, e.g. a high degree Alexander polynomial that can be explicitly determined, a Milnor fiber homotopy equivalent to a bouquet of circles, or an irreducible translated component in the characteristic variety of their complement. Monodromy eigenspaces in the first cohomology group of the corresponding Milnor fibers are also described in terms of explicit differential forms.