• Spatial Information Research
• /
• v.11 no.1
• /
• pp.23-32
• /
• 2003

TIN is applied in pondage calculation and topography analysis. And much processing time and storage capacity are needed because TIN contains information as elevation, slope and aspect. In the construction of TIN using contour, weed tolerance that is used for the simplification of line is influenced on the sampling distance of contour. The processing time and storage capacity of TIN are calculated in according to the weed tolerance of various size in this research. And we estimated OEMs standard error that is created from TIN to present reasonable weed tolerance and decided the size of weed tolerance that satisfy DEM standard error. We got TINs weed tolerance that satisfy DEM standard error(5m) was 70m and DEMs resolution is 20m as estimation result.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.247-247
• /
• 2021

국내외적으로 하도 내의 흐름을 해석하기 위해 다양한 2차원 흐름해석 모형이 적용되고 있다. 2차원 흐름해석 모형은 기존의 1차원 흐름 해석 모형에서 해석하기 어려운 확산형 홍수파 해석에 강점을 가지고 있어 도심 하천의 외수 범람 예측 등에도 사용되고 있다. 하지만 복잡한 지형 형상을 어떻게 격자로 구성하는가에 따라 해석의 효율성과 정확성이 크게 좌우된다. 초기의 2차원 흐름해석 모형은 주로 정형격자 기반의 단순한 셀을 제작하여 구동되었다. 하지만 매우 빠른 유속과 복잡한 형상을 반영하기 위해서는 전체 격자를 조밀하게 구성할 필요가 있으므로 계산 효율이 떨어지는 문제점이 있다. 그렇기 때문에 대안으로 삼각망과 혼합망 등 비정형 격자를 사용하여 필요한 구역만 격자를 조밀하게 구성하는 방법을 사용하고 있지만 이 방법 또한 추가적인 계산 과정에 따른 계산 시간의 증가가 필연적이다. 따라서 최근에는 정형격자와 비정형격자에 대하여 wet-dry front matrix 최적화, 절점제거법 등 다양한 기법을 통하여 계산 효율을 향상시키고 있는 실정이다. 따라서 본 연구에서는 HLLC Rimann solver와 2차 정확도 기법인 MUSCL-Hancock Method를 적용한 유한체적기반 천수방정식을 기반으로 다양한 격자 구성에 따른 2차원 흐름해석 모형의 효율성 분석을 수행하고, 이를 통해 최적의 흐름해석 방안을 제시하고자 한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.23 no.3
• /
• pp.251-260
• /
• 2005

The Development of CCD has contributed to great advancement in mapping technology with giving benefits to research community of photogrammetry. The purpose of this paper is to find the best selection of interpolation method for creating a terrain model form close range digital photogrammetry. T-test as a kind of statistical analysis was conducted to analyze the similarity of hydraulic model with close range digital photogrammetry and trigonometric leveling. Also, many interpolation methods such as inverse distance, kriging, nearest neighbor and TIN about the hydraulic model interpolation were conducted to compare the results for computer to display actual terrain an optimum interpolation of the digital elevation model form close range digital photogrammetry. The results revealed that kriging and TIN interpolation were efficient methods to judge the hazard interpolation law by analyzing geometric similarity of hydraulic model against hydraulic model application.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.2 no.2
• /
• pp.1-13
• /
• 1984

Projection has been used in order to indicate the horizontal position of triangulation stations which had been existed on the earth surface. In our country, the plane Rectangular coordinate of the triangulation station is computed by means of Gauss Double projection. But it proves to contain many errors according to the difference in Latitude and longitude. Therefore, in this study Transverse Mercator projection which is known to contain less error than Gauss Double projection in an applied region is introduced, and the results obtain by two these projections and the value today in our country are compared and analysed. when an another plane Rectangular Coordinate system is added to the present 3-plane Rectangular Coordinate system, there is an object inshowing the best position.

• Computational Structural Engineering
• /
• v.6 no.3
• /
• pp.99-112
• /
• 1993

One of the characteristics of Delaunay-Voronoii methods of mesh generation is local remeshing ability in comparison with other methods, which is very useful in adaptive finite element applications. Main part of the process is to construct remeshing element group out of the whole elements and to remesh it. Adjacent element array, accompanied with an additional algorithm of several lines, is introduced to make the process simple so that implementation of the concept is possible at the level of general PC users.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.7 s.250
• /
• pp.800-808
• /
• 2006

In this paper, the CL surface transformation approach that inversely deforms the 3-axis tool path generated on the deformed CL surface to a 5-axis tool path is introduced. The proposed CL surface transformation approach can be used if the orientation of the cutter is predefined. The CL surface based 3-axis tool path generation algorithms that have been improved well can be applied to the f-axis tool path generation.

• Korean Journal of Computational Design and Engineering
• /
• v.9 no.4
• /
• pp.382-386
• /
• 2004

This paper presents an algorithm for the triangular mesh intersection problem. The key aspect of the proposed algorithm is to reduce the number of triangle pairs to be checked for intersection. To this end, it employs two different approaches, the Y-group approach and the space partitioning approach. Even though both approaches have the same objective of reducing the number of triangular-triangular intersection (TTI) pairs, their inherent characteristics are quite different. While the V-group approach works by topology (reduces TTI pairs by guaranteeing no intersection among adjacent triangles), the space partitioning approach works by geometry (reduces TTI pairs by guaranteeing no intersection among distant triangles). The complementary nature of the two approaches brings substantial improvement in reducing the number TTI pairs.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.9 s.174
• /
• pp.202-211
• /
• 2005

This paper introduces and illustrates the results of a new method fer offsetting triangular mesh by moving all vertices along the multiple normal vectors of a vertex. The multiple normal vectors of a vertex are set the same as the normal vectors of the faces surrounding the vertex, while the two vectors with the smallest difference are joined repeatedly until the difference is smaller than allowance. Offsetting with the multiple normal vectors of a vertex does not create a gap or overlap at the smooth edges, thereby making the mesh size uniform and the computation time short. In addition, this offsetting method is accurate at the sharp edges because the vertices are moved to the normal directions of faces and joined by the blend surface. The method is also useful for rapid prototyping and tool path generation if the triangular mesh is tessellated part of the solid models with curved surfaces and sharp edges. The suggested method and previous methods are implemented on a PC using C++ and illustrated using an OpenGL library.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.46 no.4
• /
• pp.65-71
• /
• 2004

Stress Path Search Model of Evolutionary Structural Successive Optimization (SPSMESO) using Triangular Irregular Network(TIN) was developed for improving over burden at initial design of ESO and strict stress direction of strut-and-tie model and truss model. TIN was applied for discretizing structures in flexible stress path and segments of TIN was analyzed as one-dimensional line element for calculating stress. Finally, stress path was searched using ESO algorithm. SPSMESO was efficient to express the direction of stress for 2D structure and time saving.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.49 no.6
• /
• pp.37-46
• /
• 2007

In designing the structure, the stress path is the basic data. But the stress path is not standardized to analysis the structure. So the one-dimensional frame element structure model with the triangle irregular network is used to solve the problem. And the refined evolutionary structural optimization(RESO) used in structural topology optimization is applied to this study. Through this process, the search method of the stress path is advanced and the burden of the calculation. is reduced.