• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.151-156
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• 2000

Delaunay triangulation is well balanced in the sense that the triangles tend toward equiangularity. And so, Delaunay triangulation hasn't some slivers triangle. It's commonly used in various field of CAD applications, such as shape reconstruction, solid modeling and volume rendering. In this paper, an improved Delaunay triangulation is proposed in 2-dimensions. The suggested algorithm subdivides a uniform grids into sub-quad grids, and so efficient where points are non-uniform distribution. To get the mate from quad-subdivision algorithm, the area where triangulation-patch will be most likely created should be searched first.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.616-619
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• 2002

The z-map structure is widely used for NC tool path verification as it is very simple and fast in calculation of Boolean operations. However, if the number of the x-y grid points in a z-map is increased to enhance its accuracy, the computation time for NC verification increases rapidly. To reduce this computation time, we proposed a NC verification method using 3-D graphic acceleration hardwares. In this method, the z-map of the resultant workpiece machined by a NC program is obtained by rendering tool swept volumes along tool pathos and reading the depth buffer of the graphic card. The experimental results show that this hardware-based method is faster than the conventional software-based method.

• 한국소음진동공학회논문집
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• 제11권9호
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• pp.462-474
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• 2001

In this paper, Generalized Differential Quadrature Method is applied to the buckling analysis of built-up columns without or with stay plates. numerical analysis using GDQM is carried out for various boundary conditions(simply supported conditions, fixed conditions, fixed-simply supported conditions), dimensionless stiffness parameter and dimensionless inertia moment parameter. The accuracy and convergence of solutions are compared with exact solutions of Gjelsvik to validate the results of GDQM. Results obtained by this method are as follows. 91) This method can yield the accurate numerical solutions using few grid points. (2) The buckling load of built-up column increases as the dimensionless stiffness parameter decreases. (3) The effects of boundary conditions on the buckling load are not considerable as the dimensionless stiffness parameter increases. (4) The buckling load of built-up column increases due to the stay plate.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권6호
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• pp.334-338
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• 2006

The finite volume time domain(FVTD) method gives accurate results for the calculation of electromagnetic wave propagation but it should be noted that the number of sampling points per wavelength should be increased when more accurate numerical results are required. Moreover it requires large amount of computer memory resources. In this paper we propose a modified FVTD that employs a time subdivision. The local time-subdivided FVTD(FVTD-LTS) method is enough to divide the space domain grid with a large step size. This method can reduce computation time and memory resources. To validate the proposed method, sever numerical examples are presented. We have then shown that the proposed method yields a reasonable solution.

• 설비공학논문집
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• 제3권1호
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• pp.11-25
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• 1991

The steady, incompressible developing 3-dimensional turblent flow in a square sectioned curved duct has been investigated by using partially-parabolic equation and Finite Analytic Method. The calculation of turbulent flow field is performed using 2-equation K-$\epsilon$ turbulence model, modified wall function, simpler algorithm and numerically generated body fitted coordinates. Iso-mean velocity contours at the various sections are compared with the existing experimental data and elliptic solutions by other authors. In the region of $0^{\circ}<{\theta}<71^{\circ}$, present results agree with the experimental data much better than the elliptic solution for the similar number of grid points. Furthermore, for the same tolerance, the present solution converges four times faster than the elliptic solution.

• 한국전산유체공학회지
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• 제16권3호
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• pp.22-28
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• 2011

Laminar Flow over an equilateral triangular cylinder is studied for several inflow angles. Under an uniform flow of $Re_d$=50,75,100,125,150, the triangular cylinder is rotated by ${\theta}$=$0^{\circ}$,$15^{\circ}$,$30^{\circ}$,$45^{\circ}$,$60^{\circ}$,$75^{\circ}$,$90^{\circ}$,$105^{\circ}$. The governing equations are solved by the PISO algorithm based on the finite volume method of the unstructured grid system. The effects of the inflow angle on the vortex-shedding flows are investigated. The Strouhal number shows a minimum at ${\theta}$=$60^{\circ}$. It is closely related to the variation of pressure and flow structure induced by the movement of separation points.

• 한국전산유체공학회지
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• 제14권4호
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• pp.93-100
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• 2009

The gridless (or meshfree) methods, such as MPS, SPH, FPM an so forth, are feasible and robust for the problems with moving boundary and/or complicated boundary shapes, because these methods do not need to generate a grid system. In this study, a gridless solver, which is based on the combination of moving least square interpolations on a cloud of points with point collocation for evaluating the derivatives of governing equations, is presented for two-dimensional unsteady incompressible Navier-Stokes problem in the low Reynolds number. A MAC-type algorithm was adopted and the Poission equation for the pressure was solved successively in the moving least square sense. Some typical problems were solved by the presented solver for the validation and the results obtained were compared with analytic solutions and the numerical results by conventional CFD methods, such as a FVM.

• 한국측량학회지
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• 제2권1호
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• pp.46-53
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• 1984

본 연구에서는 표본지역에 대하여 수치지형 모델(DTM)에 의한 수치등선도를 자동작성하였으며, 이를 일반등고선에 상대비교한 결과 거의 하등한 정확도를 갖는 것이 확인되었다. 표본데이타는 A-10 도화기상에서 실체모델로부터 정방형 격자로 841점 $(29{\times}29)$을 직접 추출하였다. 이 데이타를 유한요소개념에 의하여 보간을 실시하고 최종성과인 수치등고선을 일반등고선에 상대비교하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.340-342
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• 2001

This paper presents a utility interactive photovoltaic generation system with the angle of inclination and direction. This paper summarizes the results of these efforts by offering a snapshot of the configuration of photovoltaic in residential applications. The status of PV system components and inter-connection and safety equipment will be summarized. also, This System is able to alteration the angle of inclination and direction. Hence this paper discusses only points that might be useful for application.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
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• pp.46-49
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• 2008

This research does Complexity form, Interior epidermis cell re-organization, Object discovery that have correct numerical value concept by purpose. Research applied by Grid re-organization in form generation, Parameter variation of cell unit (morphor, tweener), Symbol, pattern of variation, self-organization cell substitution order. Representation through 3d digital modeler of polygon, Nurbs and street-sheet program(x,y,z coordinates & Network way of points) etc. of main work. Investigator specified numbers of U profiles*30, V point-20 that is 600 Paramaters individual in volume, and define circle radius of lighting in object, Projection size variously and tried difference. Transposition cell to point and Heightened brightness of color using pointillism of painting. Led lighting cell object is expressed being decoded by digital code.