• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.8-13
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• 2008

In this study, an adaptive node generation procedure in the radial point interpolation method is proposed. Since we set the initial configuration of nodes by subdivision of background cell, abrupt changes of inter-nodal distance between higher and lower error regions are unavoidable. This unpreferable nodal spacing induces additional errors. To obtain the smoothy nodal configuration, it's regenerated by local Delaunay triangulation algorithm This technique was originally developed to generate a set of well-shaped triangles and tetrahedra. To demonstrate the performance of proposed scheme, the results of making optimal nodal configuration with adaptive refinement method are investigated for stress concentration problems.

• 한국CDE학회논문집
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• 제9권4호
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• pp.294-305
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• 2004

Highly detailed geometric models are rapidly becoming commonplace in computer graphics and other applications. These complex models, which is often represented as complex1 triangle meshes, mainly suffer from the vast memory requirement for real-time manipulation of arbitrary geometric shapes without loss of data. Various techniques have been devised to challenge these problems in views of geometric processing, not a representation scheme. This paper proposes the new mesh structure for the compact representation and the efficient handling of the highly complex models. To verify the compactness and the efficiency, the memory requirement of our representation is first investigated and compared with other existing representations. And then we analyze the time complexity of our data structure by the most critical operation, that is, the enumeration of the so-called one-ring neighborhood of a vertex. Finally, we evaluate some elementary modeling functions such as mesh smoothing, simplification, and subdivision, which is to demonstrate the effectiveness and robustness of our mesh structure in the context of the geometric modeling and processing.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권1호
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• pp.1-15
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• 2016

The continuous analysis, such as smoothness and uniform convergence, for polynomials and polynomial-like functions using differential operators have been studied considerably, parallel to the study of discrete analysis for these functions, using difference operators. In this work, for the difference operator ${\nabla}_h$ with size h > 0, we verify that for an integer $m{\geq}0$ and a strictly decreasing sequence $h_n$ converging to zero, a continuous function f(x) satisfying $${\nabla}_{h_n}^{m+1}f(kh_n)=0,\text{ for every }n{\geq}1\text{ and }k{\in}{\mathbb{Z}}$$, turns to be a polynomial of degree ${\leq}m$. The proof used the polynomial convergence, and additionally, we investigated several conditions on convergence to polynomials.

• 한국대기환경학회지
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• 제16권5호
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• pp.511-520
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• 2000

The urban atmosphere is characterized by th difference in surface and atmospheric environment between urban and more natural area. To investigate th climatic effect of land use type and anthropogenic heat of urban on wind field, numerical simulations were carried out under typical summer synoptic condition. The wind model PNU_MCM(Pusan National University Mesoscale Circulation Model) is based on the three-dimensional Boussinesq equations, taking into account the hydrostatic assumption . Since lane-use differs over every subdivision on Pusan the surface energy budget model includes sub0grid parameterization scheme which can calculate the total heat flux over a grid surface composed of different surfaces. The simulated surface wind agrees well with the observed value, and average over 6 days which represent typical summer lan-sea breeze days, August 1998, i.e. negligible gradient winds and almost clear skies. Urbanization makes sea-breeze enhance at day and reduce land-breeze at night. The results show that contribution of land-use type is much larger than that of anthropogenic heat in Pusan.

• 교육시설
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• 제9권4호
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• pp.5-13
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• 2002

This paper aims to analyse design conditions and propose schematic design for Jangsung High School in Pohang. As for site conditions, it has the size of $14,900m^2$ and a rather flat condition near to the ocean East Sea. And the area is under development with land subdivision method expecting high density housing around it. As a program, Education Facilities Bureau required to provide 36 classes and supporting facilities. To design the schemes, we followed the 7th education policy guidelines. During the design development stage, 3 alternatives are suggested as in the paper. However, staffs of Education Bureau and teachers favoured and selected our scheme, which gives symbolic image, as a new high school education environment.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 국내 LBS 기술개발 및 표준화 동향세미나
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• pp.14-19
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• 2004

RFID는 라디오 주파수 기반의 자동 인식 데이터 수집 장치로서 유비쿼터스 컴퓨팅 기반 기술의 핵심 분야이다. RFID 태그(전자태그)가 부착된 개체의 위치를 저장할 수 있기 때문에 시간에 따라 위치가 변하는 이동체와 유사하다. 그러나 태그 객체는 판독기(reader)의 위치로 인식되며 일정 수 이상의 객체들이 같은 시간에 함께 이동하는 특징을 가지기 때문에 기존의 이동체 모델링 방법을 사용하여 전자 태그 객체를 표현하면 색인의 성능이 저하되는 문제가 발생한다. 이 논문에서는 시공간 질의를 처리하는 색인의 성능을 개선하기 위하여 태그 객체의 특징을 반영한 모델링 기법을 제안한다. 제안한 모델링 기법에서 간격 데이터 개념을 기반으로 시간과 공간 도메인 외에 식별자 도메인을 추가하여 태그 객체를 표현한다. 그리고 세 가지 도메인을 이용하여 태그 객체에 대한 색인을 구성한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.537-540
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• 1988

This paper presents a new shadow testing acceleration scheme for ray tracing called hybrid shadow testing(HST), based on conditional switching between the conventional shadow testing method and Crow's shadow volume method, with the object polygons as well as the shadow polygons registered onto the corresponding cells under the 3-D space subdivision environment. Despite the preprocessing time for the generation and registration of the shadow polygons, the total shadow testing time of the new algorithm was approximately 50 % of that of the conventional shadow testing method for several examples while the total ray tracing time was typically reduced by 30% from the conventional approach.

• 교육시설
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• 제9권6호
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• pp.15-23
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• 2002

This paper aims to analyse design conditions and propose schematic design for Doryang High School in Gumi. As for site conditions, it has the size of $14,988m^2$ and a rather flat condition. And the area is under development with land subdivision method expecting high density housing around it. As a program, Education Facilities Bureau required to provide 36 classes and supporting facilities. To design the schemes, we followed the 7th education policy guidelines. During the design development stage, 3 alternatives are suggested as in the paper. However, staffs of Education Bureau and teachers favoured and selected our scheme, which gives symbolic image, as a new high school education environment.

• 대한전자공학회논문지
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• 제26권3호
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• pp.95-104
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• 1989

본 논문은 3차원적 분할공간 환경에서 종래의 음영검사법과 Crow의 음영입체법을 상황에 따라 우리하도록 선택하는 혼합음영검사법을 소개하고 파라메타화를 통하여 그 선택의 최적화를 꾀하였다. 추가적인 선행계산시간이 소요됨에도 불구하고 제안된 혼합음영검사법은 여러가지 예제화면들에 재하여 종래의 방법에 비하여 음영계산시간에 있어서는 50%, 전체묘화시간에 있어서는 30%정도씩의 CPU시간단축효과를 보였다. 그 원인은 음영검사의 선택적 사용을 통하여 그림자영역의 일관성(coherency)을 이용한데에 있다. 연속되는 두 반사점사이에 존재하는 음영다각형의 갯수를 나타내는 $N_{th}$라는 파라메타가 음영검사의 효과적 선택을 위한 지표가 되며, 묘화환경의 통계적 수치로부터 이 값을 알아내는 방법이 제안되고 실험적 결과와 비교된다.

• Journal of Mechanical Science and Technology
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• 제20권1호
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• pp.110-124
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• 2006

The multi scale wavelet-Galerkin method implemented in an adaptive manner has an advantage of obtaining accurate solutions with a substantially reduced number of interpolation points. The method is becoming popular, but its numerical efficiency still needs improvement. The objectives of this investigation are to present a new numerical scheme to improve the performance of the multi scale adaptive wavelet-Galerkin method and to give detailed implementation procedure. Specifically, the subdomain technique suitable for multiscale methods is developed and implemented. When the standard wavelet-Galerkin method is implemented without domain subdivision, the interaction between very long scale wavelets and very short scale wavelets leads to a poorly-sparse system matrix, which considerably worsens numerical efficiency for large-sized problems. The performance of the developed strategy is checked in terms of numerical costs such as the CPU time and memory size. Since the detailed implementation procedure including preprocessing and stiffness matrix construction is given, researchers having experiences in standard finite element implementation may be able to extend the multi scale method further or utilize some features of the multiscale method in their own applications.