• Title/Summary/Keyword: geometrical representation

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Spatial Representation of Geometrical Relations in the Drawings of Young Children (유아의 기하학적 구성물의 그리기 작업에 대한 연구)

  • Hong, Hae Kyung
    • Korean Journal of Child Studies
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    • v.22 no.2
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    • pp.315-327
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    • 2001
  • This study investigated young children's spatial representation of geometrical relations based on their drawings of cube buildings. One hundred seventy-six children from 3 to 6 years of ages were selected from private kindergartens and day care centers. Their drawings were classified into 6 developmental levels: level 1 - drawings show only scribbles or several circles; level 2 - drawings show plane squares from a front view; level 3 - positional relations are included in the drawings; level 4 - separate-joint relations or the general outline of a cube building are shown; level 5 - rotated drawing and an additional square for hidden faces are attempted to represent the lateral view; level 6 - parallel lines are drawn to represent 3-dimensional structures. Three-to four-year-olds were between levels 1 and 2; four-to six-year olds were between levels 3 and 4; and children over six years old were between levels 3 and 5.

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Geometrical Featured Voxel Based Urban Structure Recognition and 3-D Mapping for Unmanned Ground Vehicle (무인 자동차를 위한 기하학적 특징 복셀을 이용하는 도시 환경의 구조물 인식 및 3차원 맵 생성 방법)

  • Choe, Yun-Geun;Shim, In-Wook;Ahn, Seung-Uk;Chung, Myung-Jin
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.5
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    • pp.436-443
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    • 2011
  • Recognition of structures in urban environments is a fundamental ability for unmanned ground vehicles. In this paper we propose the geometrical featured voxel which has not only 3-D coordinates but also the type of geometrical properties of point cloud. Instead of dealing with a huge amount of point cloud collected by range sensors in urban, the proposed voxel can efficiently represent and save 3-D urban structures without loss of geometrical properties. We also provide an urban structure classification algorithm by using the proposed voxel and machine learning techniques. The proposed method enables to recognize urban environments around unmanned ground vehicles quickly. In order to evaluate an ability of the proposed map representation and the urban structure classification algorithm, our vehicle equipped with the sensor system collected range data and pose data in campus and experimental results have been shown in this paper.

Structuring Element Representation of an Image and Its Applications

  • Oh, Jin-Sung
    • International Journal of Control, Automation, and Systems
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    • v.2 no.4
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    • pp.509-515
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    • 2004
  • In this paper we present the linear combination of a fuzzy opening and closing filter with locally adaptive structuring elements that can preserve the geometrical features of an image. Based on the adaptation algorithm of linear combination of the fuzzy opening and closing filter, the optimal structuring element for image representation is obtained. The optimal structuring element is an indicator of the shape and direction of an object's image, which is useful in filtering, multi resolution, segmentation, and recognition of an image.

Error analysis related to a learner's geometrical concept image in mathematical problem solving (학생이 지닌 기하적 심상과 문제해결과정에서의 오류)

  • Do, Jong-Hoon
    • Journal of the Korean School Mathematics Society
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    • v.9 no.2
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    • pp.195-208
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    • 2006
  • Among different geometrical representations of a mathematical concept, learners are likely to form their geometrical concept image of the given concept based on a specific one. A learner's image is not always in accord with the definition of a concept. This can induce his or her errors in mathematical problem solving. We need to analyse types of such errors and the cause of the errors. In this study, we analyse learners' geometrical concept images for geometrical concepts and errors related to such images. Furthermore we propose a theoretical framework for error analysis related to a learner's concept image for a general mathematical concept in mathematical problem solving.

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Geometrical dimensions effects on the seismic response of concrete gravity dams

  • Sevim, Baris
    • Advances in concrete construction
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    • v.6 no.3
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    • pp.269-283
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    • 2018
  • This study presents the effects of geometrical dimensions of concrete gravity dams on the seismic response considering different base width/dam height (L/H) ratios. In the study, a concrete gravity dam with the height of 200 m is selected and finite element models of the dam are constituted including five different L/H ratios such as 0.25, 0.5, 0.75, 1.00, 1.25. All dams are modeled in ANSYS software considering dam-reservoir-foundation interaction. 1989 Loma Prieta earthquake records are applied to models in upstream-downstream direction and linear time history analyses are performed. Dynamic equilibrium equations of motions obtained from the finite element models of the coupled systems are solved by using Newmark time integration algorithm. The seismic response of the models is evaluated from analyses presenting natural frequencies, mode shapes, displacements and principal stresses. The results show that the L/H ratios considerably affect the seismic response of gravity dams. Also, the model where L/H ratio is 1.00 has more desirable results and most appropriate representation of the seismic response of gravity dams.

Parametric Macro for Two-Dimensional Layout on the Auto-CAD System

  • Kim, Yunyong;Park, Jewoong
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.10a
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    • pp.253-260
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    • 2000
  • In recent years, a number of successful nesting approaches have been developed by using the various heuristic algorithms, and due to their application potential several commercial CAD/CAM packages include a nesting module for solving the layout problem. Since a large portion of the complexity of the part nesting problem results from the overlapping computation, the geometric representation is one of the most important factors to reduce the complexity of the problem. The proposed part representation method can easily handle parts and raw materials with widely varying geometrical shape by using the redesigning modules. This considerably reduces the amount of processed data and consequently the run time of the computer. The aim of this research is to develop parametric macro for two-dimensional layout on the Auto-CAD system. Therefore, this research can be called "pre-nesting".

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Parametric Macro for Two-Dimensional Layout on the Auto-CAD System

  • Kim, Yunyoung;Park, Jewoong
    • Journal of Ship and Ocean Technology
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    • v.4 no.3
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    • pp.13-20
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    • 2000
  • In recent years, a number of successful nesting approaches have been developed by using the various heuristic algorithms, and due to their application potential several commercial CAD/CAM packages include a nesting module for solving the layout problems. Since a large portion of the complexity of the part nesting problem results from the overlapping computation, the geometric representation is one of the most important factors to reduce the complexity of the problem. The proposed part representation method can easily handle parts and raw materials with widely varying geometrical shape by using the redesigning modules. This considerably reduces the amount of processed data and consequently the run time of the computer. The aim of this research is to develop parametric macro for two-dimensional layout on the Auto-CAD system. Therefore, this research can be called "pre-nesting".ing".uot;.

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대수체계의 발견에 관한 수학사적 고제

  • 한재영
    • Journal for History of Mathematics
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    • v.15 no.3
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    • pp.17-24
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    • 2002
  • It will be described the discovery of fundamental algebras such as complex numbers and the quaternions. Cardano(1539) was the first to introduce special types of complex numbers such as 5$\pm$$\sqrt{-15}$. Girald called the number a$\pm$$\sqrt{-b}$ solutions impossible. The term imaginary numbers was introduced by Descartes(1629) in “Discours la methode, La geometrie.” Euler knew the geometrical representation of complex numbers by points in a plane. Geometrical definitions of the addition and multiplication of complex numbers conceiving as directed line segments in a plane were given by Gauss in 1831. The expression “complex numbers” seems to be Gauss. Hamilton(1843) defined the complex numbers as paire of real numbers subject to conventional rules of addition and multiplication. Cauchy(1874) interpreted the complex numbers as residue classes of polynomials in R[x] modulo $x^2$+1. Sophus Lie(1880) introduced commutators [a, b] by the way expressing infinitesimal transformation as differential operations. In this paper, it will be studied general quaternion algebras to finding of algebraic structure in Algebras.

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AR based ornament design system for 3D printing

  • Aoki, Hiroshi;Mitanin, Jun;Kanamori, Yoshihiro;Fukui, Yukio
    • Journal of Computational Design and Engineering
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    • v.2 no.1
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    • pp.47-54
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    • 2015
  • In recent years, 3D printers have become popular as a means of outputting geometries designed on CAD or 3D graphics systems. However, the complex user interfaces of standard 3D software can make it difficult for ordinary consumers to design their own objects. Furthermore, models designed on 3D graphics software often have geometrical problems that make them impossible to output on a 3D printer. We propose a novel AR (augmented reality) 3D modeling system with an air-spray like interface. We also propose a new data structure (octet voxel) for representing designed models in such a way that the model is guaranteed to be a complete solid. The target shape is based on a regular polyhedron, and the octet voxel representation is suitable for designing geometrical objects having the same symmetries as the base regular polyhedron. Finally, we conducted a user test and confirmed that users can intuitively design their own ornaments in a short time with a simple user interface.

An interpretation of intelligence based on mathematical integration of elementary mechanisms in biology

  • Chauvet, Gilbert A.
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.353-357
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    • 2003
  • Although it is more and more well accepted that modeling is a help for experimental biology, little is known about how to integrate physiological processes in general. The fact that no general theory exist in biology has big consequences, the most important being the difficulty to integrate biological phenomena. 1 will present a solution for the three dependent following issues: i) in an appropriate theoretical framework, integration consists in coupling models that each describe physiological mechanisms (formalization is a necessary condition to integration); ii) a biological theory with its own concepts leads to unifying principles in biology that are different from and complementary to physical principles; iii) such a formalized theory consists in a representation in terms of functional interactions and a specific formalism(S-Propagator). Hence a biological theory is of a topological and geometrical nature, in contrast to physical theories that are of a geometrical nature. An application to the interpretation of intelligence is proposed, based on the "intelligence"of movement.

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