• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.415-423
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• 2015

In this study, we present a grid refinement model in the lattice Boltzmann method (LBM) for two-dimensional incompressible fluid flow. That is, the model combines the desirable features of the lattice Boltzmann method and stream function-vorticity formulations. In order to obtain an accurate result, very fine grid (or lattice) is required near the solid boundary. Therefore, the grid refinement model is used in the lattice Boltzmann method for stream function-vorticity formulation. This approach is more efficient in that it can obtain the same accurate solution as that in single-block approach even if few lattices are used for computation. In order to validate the grid refinement approach for the stream function-vorticity formulation, the numerical simulations of lid-driven cavity flows were performed and good results were obtained.

• 전기의세계
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• v.23 no.6
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• pp.20-23
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• 1974

본고에서는 다음의 내용을 다루었다. 1. 발전기기의 기전도화 및 대용량화 2. 전동기기의 세밀화 3. 전기기기의 고효율화

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.6
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• pp.621-629
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• 2008

Procedures involved in the refinement of the regional geoid for the area encompassing the Korean peninsula and the East Sea are described, and the computational results are provided. A comparison between the geoid height data, the mean sea surface height and the final product of the refinement work is provided and analyzed. The regional marine geoid thus refined seems to have a better resolution, in terms of its correlation with the bathymetry, and shows the bottom features in a more detailed manner when compared with previously used procedures. The general pattern of the computed geoid profile matches reasonably well with the existing studies, where the correlations between the refined regional marine geoid and the bathymetry are (1) 0.44 for the area $117{\sim}142.5^{\circ}E/24{\sim}52^{\circ}N$ and (2) 0.47 for the area $127{\sim}142.5^{\circ}E/32{\sim}50^{\circ}N$ in the East Sea respectively.

• The Korean Publising Journal, Monthly
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• s.365
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• pp.74-75
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• 2006

• Spatial Information Research
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• v.14 no.3 s.38
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• pp.321-334
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• 2006

3D spatial data are of increasing interest in landscape analysis, urban planning and map services based on Web, because of its reality. But the amount of 3D spatial data are very large in comparison with 2D spatial data. Therefore it is necessary to have a efficient methods to transfer and visualize 3D spatial data. The concept of Level of Detail in Computer Graphics is effective. This paper briefly presents two LOD data models of data transmission based on the spatial data model of international standards. First, it is separated LOD model that gives a LOD level to object. Second is Selective LOD model that gives a LOD level to object's element. We compared the efficiency of 3D data transmission based on two LOD model.

• The Science & Technology
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• v.30 no.10 s.341
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• pp.82-83
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• 1997

콩의 유전자지도 작성으로 고품질의 새로운 품종개발에 심혈을 기울이고 있는 농촌진흥청 전작과 농업연구사 이석하박사. 우리나라가 콩의 고향이라고 말하는 이박사는 유전자지도를 더욱 세밀화하여 앞으로 나물콩, 밥밑콩, 두부용콩, 비린내 없는 콩 등의 품종개발에도 연구를 계속하고 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.1004-1014
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• 2001

The fully automatic algorithm from initial finite element mesh generation to remeshing in two dimensional geometry is introduced using bubble packing method (BPM) for finite element analysis. BPM determines the node placement by force-balancing configuration of bubbles and the triangular meshes are made by Delaunay triangulation with advancing front concept. In BPM, we suggest two node-search algorithms and the adaptive/recursive bubble controls to search the optimal nodal position. To use the automatically generated mesh information in FEA, the new enhanced bandwidth minimization scheme with high efficiency in CPU time is developed. In the remeshing stage, the mesh refinement is incorporated by the control of bubble size using two parameters. And Superconvergent Patch Recovery (SPR) technique is used for error estimation. To verify the capability of this algorithm, we consider two elasticity problems, one is the bending problem of short cantilever beam and the tension problem of infinite plate with hole. The numerical results indicate that the algorithm by BPM is able to refine the mesh based on a posteriori error and control the mesh size easily by two parameters.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.45-46
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• 2013

본 논문에서는 깊이 영상과 컬러 영상의 매칭을 통한 강인한 전경 객체 영역화 기법을 제안한다. 기존의 컬러 영상 기반 객체 영역화 알고리즘은 배경과 객체의 색상이 유사한 경우 정확한 객체 영역화가 어렵다. 깊이 영상을 이용하면 이러한 오 검출을 줄일 수 있지만, 깊이 영상 취득 장비의 오류로 인하여 검출되는 객체 외곽선이 컬러 영상에 비해 세밀하지 못한 단점이 있다. 따라서, 깊이 영상의 외곽선을 비교적 세밀한 컬러 영상의 외곽선에 매칭시킨다. 아울러, 서로 다른 센서에서 취득한 두 영상을 매칭하기 위하여, 정규화된 상호연관성(normalized cross correlation)을 유사도 척도로 사용한다. 실험을 통하여 제안하는 알고리즘이 전경 객체 영역화의 오 검출을 줄이며, 동시에 객체 외곽선을 충실히 복원함을 확인한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.274-274
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• 2016

일반적으로 수공구조물의 설계지점은 홍수량 자료가 없는 경우가 대부분이다. 이러한 미계측유역의 홍수빈도를 추정하기 위한 여러방법들 중 지수홍수법을 이용한 지역홍수빈도분석을 본 연구에서 수행하였다. 특히, 지수홍수법의 주요인자 중 하나인 평균홍수량의 지역화를 위한 방법으로 홍수량과 유역면적과의 관계가 멱함수 법칙(power law)을 따른다는 가정에 따른 경험관계를 도출하였다. 보다 세밀한 분석을 위해 대상유역 전체를 하나의 그룹, 공간 근접성에 따른 추가적인 세부적인 그룹으로 분류하여 각각의 결과를 분석하였다. 연구결과에 의하면, 미계측 지점의 홍수량 추정시에는 인근의 계측지역 즉, 직상하류 유역의 비유량의 관계를 사용하는 것이 타당할 것으로 판단된다. 또한 미계측 유역에 대한 홍수빈도를 추론하기 위해서는 지역홍수빈도해석 자체도 중요하지만, 지역의 세밀한 구분과 그에 따른 지역화 경험관계 개발이 중요함을 확인할 수 있었다.

• Spatial Information Research
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• v.22 no.3
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• pp.89-99
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• 2014

The aim of this study is to represent the residential population distribution in Seoul, Korea more precisely through the dasymetric mapping method. Dasymetric mapping can be defined as a mapping method to calculate details from truncated spatial distribution of main statistical data by using ancillary data which is spatial data related to the main data. In this research, there are two types of data used for dasymetric mapping: the population data (2010) based on a output area survey in Seoul as the main data and the building footprint data including register information as ancillary spatial data. Using the binary method, it extracts residential buildings as actual areas where residents do live in. After that, the regression method is used for calculating the weights on population density by considering the building types and their gross floor areas. Finally, it can be reproduced three-dimensional density of residential population and drew a detailed dasymetric map. As a result, this allows to extract a more realistic calculating model of population distribution and draw a more accurate map of population distribution in Seoul. Therefore, this study has an important meaning as a source which can be applied in various researches concerning regional population in the future.