• Annual Conference of KIPS
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• 2023.05a
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• pp.735-737
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• 2023

본 논문에서는 대퇴골의 3D 메쉬 모델에 대해 원통형 좌표계(cylindrical coordinate system)를 생성하는 방법을 제안한다. 원통형 좌표계는 대퇴골 메쉬의 방향에 따라 장축 및 단축을 결정한 뒤, 대퇴골을 포함하는 원통(right circular cylinder)을 계산하여 생성된다. 실험을 통해, 생성된 원통형 좌표계에서 균일하게 생성한 삼각형 메쉬(triangular mesh)를 대퇴골 메쉬에 투사한 결과를 보인다.

• Geophysics and Geophysical Exploration
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• v.23 no.2
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• pp.67-71
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• 2020

In this study, we derive closed-form expressions of magnetic gradient tensor due to a circular cylinder. Because the expression for magnetic field has been derived in a previously conducted study, expressions are developed for the magnetic gradient tensor based on the derivatives of the expressions of magnetic field with respect to the variables of the Cartesian coordinates. Furthermore, expressions are derived for the magnetic gradient tensor based on the relations between the Cartesian and cylindrical coordinates in the derivative because the expression for magnetic field contains variables of cylindrical coordinates owing to its axial symmetry.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1054-1061
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• 2007

In this paper, the comparison between UPML and Liao's absorbing boundary condition in the FDTD(Finite-Difference Time-Domain) method was performed for the analysis of the 2D cylindrical coordinate system. Generally, it is known as the absorbing characteristics of the UPML is bro than Liao's absorbing boundary condition in the 2D rectangular coordinate. The simulation results in this paper showed that Liao's original absorbing boundary condition is better than other two absorbing boundary conditions, Liao's modified condition and UPML. We concluded that more numerical, theoretical studies, simulations and verifications for various absorbing boundary conditions will be needed to get more accurate results for the design of useful 2D cylindrical microwave circuits.

• Geophysics and Geophysical Exploration
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• v.5 no.3
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• pp.206-216
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• 2002

The finite element method (FEM), a powerful numerical modeling tool for solving various engineering problems, is frequently applied to three-dimensional (3-D) modeling thanks to its capability of discretizing and simulating the shape of model with finite number of elements. Considering the accuracy of the solution and computing time in modeling of engineering problems, it is preferable to construct physical continuity and simplify mesh system. Although there exist systematic mesh generation systems for arbitrary shaped model, it is hard to model a simple cylinder in terms of 3-D coordinate system especially in the vicinity of the central axis. In this study I adopt cylindrical coordinate system for modeling the 3-D model space and define the origin of the coordinates with mathematically clear coordinate transformation. Since we can simulate the whole space with hexahedral elements, the cylindrical coordinate system is effective in handling the 3-D model structure. The 3-D do resistivity modeling scheme developed in this study provides basie principle for borehole-to-surface resistivity survey, which can be a useful tool for the application to environmental problem.

• Annual Conference of KIPS
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• 2012.11a
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• pp.359-361
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• 2012

본 논문에서는 깊이영상에서 상반신 포즈 분석을 위하여 원통좌표시스템을 제안한다. 깊이영상에서 포즈 후보 영역을 설정하고, 포즈 후보 영역을 이용하여 카메라로부터 신체 중심점까지의 거리와 신체 특징에 따라 원통좌표계를 설정한다. 그리고 밝기값으로 표현되는 깊이 정보를 이용하여 특징벡터를 추출한다. 추출된 원통좌표계의 특징벡터는 원형의 특징공간에 표현되고 포즈 패턴으로 분류된다. 그리고 포즈 패턴들은 특징벡터들의 평균값을 이용하여 학습되고 미리 정의된 포즈 패턴들과 유클리디언 거리로 비교하여 포즈로 분류된다. 본 논문은 상반신 포즈 후보 영역에 동적인 원통 모델을 적용하여 간단한 연산을 통해 머리와 몸통, 팔을 구분할 수 있도록 효과적인 포즈 정보 추출에 목적을 두고 있다.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.89.2-89.2
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• 2005

• Geophysics and Geophysical Exploration
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• v.23 no.1
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• pp.50-54
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• 2020

Herein, the closed-form expressions of the magnetic field due to an axially symmetric body such as a right cylinder, are derived. The magnetic field due to a right cylinder is converted from the gravity gradient tensor using Poisson's relation; the magnetic field induced by a constant magnetization can be obtained from the gravity gradient tensor with a constant density. Because of the axial symmetry of the cylinder, the expressions of gravity gradient tensor are derived in cylindrical coordinate and then transformed into Cartesian coordinates for the three components of the magnetic field using an arbitrary magnetization direction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.999-1002
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• 2002

Cylindrical Cam Mechanism is widely used in the fields of industries, such as machine tool exchangers, textile machinery. This paper proposes a method for manufacturing of cylindrical cam in Multi CNC machining center. Multi CNC machining center has two different types depending on the tilting axis. For the manufacturing procedures. in this paper the location and the orientation of cutter path are defined from shape design data of cam. The integral NC code fur the both types of multi-axis CNC machining center can be created using the coordinates mapping between design coordinates and work coordinates. Finally, CAD/CAM program is developed on $C^{＋＋}$ language. This program can display manufacturing and kinematics simulation, which can make integral NC code for multi-axis CNC machining center of two types.

• Proceedings of the Acoustical Society of Korea Conference
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• 1992.06a
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• pp.91-95
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• 1992

개영역(open boundary) 내의 변환기에 대한 음장 특성은 경계 조건이 좌표계와 정합되는 특수한 경우 헤름홀쯔 방정식풀이로 그렇지 않은 복잡한 형태의 음장에 대해서는 경계적분법이나 근사해법으로 얻어진다. 그러나 최근 이러한 문제들은 발달된 컴퓨터의 계산능력으로 유한요소법이나 경계요소법을 이용한 수치해법으로 해결되고 있다. 본 연구에서는 경계조건 변화에 따른 원통형 압전변환기의 방사임피던스 및 지향특성을 유한요소법 및 하이브리드형 무한요소법을 이용하여 구하고 기존의 해석적 결과와 비교하여 수중용 변환기 제작의 설계에 대한 기초자료를 제공하고자 한다.

• Korean Journal of Optics and Photonics
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• v.6 no.4
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• pp.373-378
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• 1995

Bending losses of bent optical waveguides are calculated by virtue of the finite difference-beam p propagation method in the cylindrical coordinate system. In order to minimize the radiating losses of bent optical waveguides, we apply the trench structure to the bent waveguides and perform the a analysis to keep track of: 1) the influence of curvature radius on the bending loss without the trench, 2) the influence of curvature radius and refractive index difference on the bending loss with the trench, 3) the influence of the trench width on the bending loss.