• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.701-704
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• 2003

약 만여개의 벤처기업 정보를 획득하여 분석, 분류와 필요한 데이터 필드를 정의하였다. 필드 정의는 구축할 데이터베이스의 기업정보로서 기업주요정보와 기업부가정보로 나누어 시스템을 설계하였다. 설계 시, 사용자 요구사항 분석은 객체지향 설계 기법을 적용하여 사용자 입장에서 본 시스템의 행동을 나타내는 유즈케이즈 다이어그램을 작성하였고 시스템의 동적인 측면을 활동의 순차적인 흐름 및 제어 흐름으로 표현한 액티비티 다이어그램을 만들었다. 기업의 TLO 기술분야와의 연결을 위하여 TLO 기술 데이터베이스 분석을 수행하였으며 데이터베이스 모델링은 요구사항 분석, 개념적 데이터베이스 모델링, 논리적 데이터베이스 모델링, 물리적 데이터베이스 모델링을 수행하였다. 그리고 웹 기반의 사용자 서비스 구현은 기업정보관리 기능, 기업정보검색 기능, 데이터베이스관리 기능, 사용자관리 기능, 환경설정 기능, 정보도우미 기능을 수행할 수 있게 시스템을 구축하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.5
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• pp.543-550
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• 2011

The gravity anomaly is a basic geophysical data applied in various fields such as geophysics, geodesy and national defense. In general, the gravity anomaly is used through a interpolation process based on the constructed database. The gravity variation, however, is appeared in various shapes depending on the topography and the density of the underground structures. Therefore, the interpolation could lead to a large differences if the gravity fields do not satisfy the assumptions on the signal behavior like linear or a certain degree polynomials. Furthermore, the interpolation does not reflect the physical characteristics of the gravity such as the harmonic condition. In this study, the gravity modeling using the plane Fourier series and radial basis functions are performed to overcome the problems in the usual interpolation. The results of the modeling is analyzed for the case of the gravity referenced navigation focused on the signal characteristics. Based on the study, it was found that the results from modeling are not much different to that from the interpolation in a smoothly varied area. In case of the highly varied area, however, a large differences are appeared among the three methods. Especially, the Fourier series shows the most smooth variations in the modeled gravity values while the highest variations appeared in the interpolation. Applying to the gravity referenced navigation, it was found that the modeling is more effective in calculation cost. It is considered that the results from this study provides a basis on effective modeling of the gravity fields in terms of the signal characteristics and resolution for various application fields.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.201-206
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• 2006

Earth sciences is undergoing a gradual but massive shift from description of the earth and earth systems, toward process modeling, simulation, and process visualization. This shift is very challenging because the underlying physical and chemical processes are often nonlinear and coupled. In addition, we are especially challenged when the processes take place in strongly heterogeneous systems. An example is two-phase fluid flow in rocks, which is a nonlinear, coupled and time-dependent problem and occurs in complex porous media. To understand and simulate these complex processes, the knowledge of underlying pore-scale processes is essential. This paper presents a new attempt to use pore-scale simulations for understanding physical properties of rocks. A rigorous pore-scale simulator requires three important traits: reliability, efficiency, and ability to handle complex microstructures. We use the Lattice-Boltzmann (LB) method for singleand two-phase flow properties, finite-element methods (FEM) for elastic and electrical properties of rocks. These rigorous pore-scale simulators can significantly complement the physical laboratory, with several distinct advantages: (1) rigorous prediction of the physical properties, (2) interrelations among the different rock properties in a given pore geometry, and (3) simulation of dynamic problems, which describe coupled, nonlinear, transient and complex behavior of Earth systems.

• 한국지구물리탐사학회:학술대회논문집
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• 2009.10a
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• pp.75-80
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• 2009

Despite its flexibility to complex geometry, three-dimensional (3D) electromagnetic(EM) modeling schemes using finite element method (FEM) have been faced to practical limitation due to the resulting large system of equations to be solved. An efficient 3D FEM modeling scheme has been developed, which can adopt either direct or iterative solver depending on the problems. The direct solver PARDISO can reduce the computing time remarkably by incorporating parallel computing on multi-core processor systems, which is appropriate for single frequency multi-source configurations. When limited memory, the iterative solver BiCGSTAB(1) can provide fast and stable convergence. Efficient 3D simulations can be performed by choosing an optimum solver depending on the computing environment and the problems to be solved. This modeling includes various types of controlled-sources and can be exploited as an efficient engine for 3D inversion.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.6
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• pp.78-90
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• 2011

This paper surveys the recent research activities regarding dynamical modeling of thermo-acoustic instabilities which are fundamental to actively control such phenomena in gas-turbine engines, rockets, and etc. For this, we introduce reduced-order modeling approaches, mainly conducted after 1990s. Particularly, we survey grey-box approaches, which determine the structure of the model based on physical rules and use system's input-output data for estimating parameters of the model. We also introduce black-box approaches using model structures without physics-based interpretation. Finally, we briefly discuss future directions and feasibilities of the research in this field.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.279-287
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• 2010

This paper surveys the recent research activities regarding dynamical modeling of high amplitude - high frequency thermo-acoustic instabilities occurring in gas-turbine engines, rockets, and etc, which are fundamental to actively control of such phenomena. For this, we introduces the reduced-order system modeling approaches, conducted after 1990s. Particularly, we deal with the grey-box approach, which determines the structure of the model based on physical rules and uses system's input-output data for estimating parameters of the model, and the black-box approach, which uses model structure without physics-based interpretation. At the end of the paper, we briefly discuss future directions and feasibilities of the research in this field.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.177-180
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• 2002

3-D 원형 브레이드 복합재료의 물리적인 물성을 계산하기 위해서는 실제와 같은 단위구조의 모델링과 이를 통한 RVE(Representative Volume Element)의 구현이 필수적이다. 실제적인 내부구조 모델링을 위해 단위구조를 2가지로 나누었으며, 실의 경로를 3차원 스플라인으로 적합시켰다. 구현한 내부구조를 통하여 공정변수와 구조변수와의 관계를 고찰하였다.

• Journal of Scientific & Technological Knowledge Infrastructure
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• s.8
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• pp.113-118
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• 2002

한국과학기술정보연구원 (KISTI) 슈퍼컴퓨팅센터의 SeeMore는 국내에서 처음으로 구현된 시스템으로 지난 해 4월에 설치되었으며, 복잡하고 방대한 계산결과를 가상현실 공간상에서 시각화하여, 효과적인 해석을 가능하게 하는 과학적 가시화 시스템이라고 할 수 있다. SeeMore에서 활용될 수 있는 적용 분야는 가상현실, 과학적 데이터의 시각화, 복잡한 데이터의 분석, 기상모델링, 양자화학, 생물정보학, 물리적 현상의 모델링에 이르기까지 무궁무진하다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.167-171
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• 2004

최근 들어 위성영상은 자료 처리 방식에 따라 지구표면이나 또는 지하면에 대한 다양한 정보(물리적인 정보, 화학적인 정보)를 얻을 수 있고 실제 지구를 가상으로 구현하는 데 활용될 수 있기 때문에 여러 산업에서 활용하고 있다. 또한 분류는 영상에 포함된 여러 가지 대상물을 구별하기 위해서 화소와 비교적 성질이 같은 화소 그룹별 특징에 대응되는 레벨을 지정하는 기술이 요구되며, 최소거리 분류법, 평행사변형법, 마하나로비스거리법(Mahanalobis Distance Method), 최대우도법(Maximum Likelihood Method)등 비교하여 분류를 수행

• Journal of the Korean School Mathematics Society
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• v.3 no.2
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• pp.17-35
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• 2000