• Journal of Korean Society for Geospatial Information Science
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• v.14 no.4 s.38
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• pp.61-70
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• 2006

This paper presents photogrammetric processing to generate digital elevation models using SPOT-5 HRG stereo images and deals with the accuracy potential of HRG (High Resolution Geometry) supermode imagery for DEM generation. After bundle adjustment was preformed for sensor modelling, digital surface models were generated through the procedures of Epipolar image resampling and image matching. The DEM extracted from HRG imagery was compared along several test sections with the the refernce DEM which was obtained from the digital topographic maps of a scale of 1 to 5000. The ratio of the zone with DEM errors less than 5m to the whole zone was 53.8%, and about 2.5m RMSE was showed when assuming that the zones larger than 5m were affected by clouds, water bodies and buildings and excluding those zones from accuracy evaluation. In addition, the three-dimensional bird's eye view model and 3D building model were producted based on the DSM which was extracted from SPOT-5 HRG data.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.709-710
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• 2002

Cancer angiogenesis is simulated using a two dimensional model. Governing equation of angiogenesis is a TAE (Tumor angiogenesis factor) conservation equation in time and space. A stochastic process model is utilized to simulate vessel formation, proliferation, and migration to a cancer pellet. Numerical results are presented especially in case of growing cancer.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.167-172
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• 1997

초전도체를 기계요소중 하나인 베어링에 응용하기 위한 연구는 임계온도가 액체질소의 비등점(77K)보다 높은 산화물 고온 초전도체가 발견된 이후 시작되었으며, 특히 최근에는 $10^4A/cm^2$이상의 임계전류밀도를 갖는 덩어리형 고온 초전도체가 용융공정을 통해 개발되어, 큰 부하지지력을 갖고 10$^{-8}$ 이하의 마찰계수를 갖는 초전도 마그네틱 베어링으로서 플라이휠 같은 에너지 저장장치에 적용시키는 연구가 국내외적으로 진행되고 있다. 고온 초전도체를 사용한 반발식 수동형 미그네틱 베어링은 Meissner effect뿐 아니라 Fluxpinning effect에 의해 자체적으로 외란에 대한 위치안정성을 가지며, 히스테리시스 손실에 의한 에너지 소산을 통해 외란에 대해 강한 감쇠능력을 가진다는 장점을 가지고 있으며, 대중량을 지지할 수 있다. 이러한 초전도체의 특성에 관한 정량적 수치해석은 초전도 베어링의 설계에 필수적이나 아직 국내에서는 그러한 시도가 없었다. 이러한 여건을 고려하여 본 연구에서는 초전도체와 자석간의 부상력 변화를 2차원 Slab모델로 수치해석하여 히스테리시스라는 주요한 특성을 고찰하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.2
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• pp.213-221
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• 1985

Two dimensional laminar natural convection in a rectangular enclousure composed of a hot bottom wall, a partially cold side wall and insulated walls except the above walls was studied by numerical analysis and also by esperiments. In the experiments, the temperature distributions in the enclosure and Nusselt number distribution along the hot and cold walls were obtained by the use of Mach-Zehnder interferometer. At first, numerical analysis with the boundary conditions of the experimental apparatus was performed and the comparison of the results of the numerical and the experimental results validated the numerical model good ennough. Heat transfer characteristics were investigated by applying the verified numerical model with the parameters, i.e. Grashof number, aspect ratio, position of cold plate and insulation condition. The results showed the optimal conditions of temperature distribution and the position of cold wall, and the characteristics of insulation materials.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.954-962
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• 1991

본 연구에서는 횡 방향으로 속도구배를 타내는 a=.part.W/.part.z에 대한 방정식을 3차원 운동량 방정식으로 부터 유도한 준 3차원 수학적 모델을 성정하여 해석하였다. 또한 수치 해석을 위하여 Chen에 의하여 고안된 유한 해석법과 2-방정식 저 레이놀즈 K-.epsilon. 난류모델, 그리고 Maeng에 의해 제시된 경계 공정 좌표계를 사용하였다. 그리 고 프로그램의 검증을 위하여 G.Ber geles가 수행한 실험치와 비교하여 그 타당성을 입증하였다.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.4
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• pp.75-83
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• 2007

Urbanized area has complex terrain with many flow paths. Almost stormwater is drained through pipe network because most area is impervious. And overland flow from the pipe network reform the surface flow. Therefore, it should be considered the drainage system and surface runoff both in urban inundation analysis. It is analyzed by using MIKE FLOOD integrated 1 dimension - 2 dimension model about Incheon Gyo urbanized watershed and compared with the results of 1 dimension model and 2 dimension model. At the result this approach linking of 2 dimension and 1 dimension pipe hydraulic model in MIKE FLOOD give accuracy that offers substantial improvement over earlier approach and more information about inundation such as water dapth, velocity or risk of flood, because it is possible to present storage of overland flow and topographical characteristic of area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5B
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• pp.509-518
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• 2010

This study aims to evaluate for flood stage on vegetated patterns by clearance space rate (CSR) using the numerical models divided into large, medium and small river in river scales with watershed area or design flood discharge. Using the HEC-RAS (1D) and RMA-2 (2D) numerical models, evaluated results of the design flood stages before vegetated modeling of these rivers which CSR in the 1D are obtained over 100% at all points in large river and medium river of except upper part 2 sections, but small river is showed about average 46.0%. It is judge that evaluated results in the 2D are obtained average 101.5% in large river, 96.7% in medium river, 71.1% in small, respectively and because of 1D mainly used to formulate of the river's master plan. However, after vegetated modeling, CSR in case of 1D showed with 91.8% in large river, 74.2% and 38.3% in medium and small rivers, respectively and 2D showed with 95.5% in large river, 86.72 and 37.0% in medium and small rivers, respectively. It is estimate that evaluated results using the 2 numerical models by the vegetated modeling are less affected the CSR for large river in a large area more than the cross section area in medium and small rivers.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.3
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• pp.248-256
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• 1995

The numerical study on the surface buoyant jets has remained of requiring more intensive investigation for problems due to the treatments of free surface, Reynolds stress/flux terms in turbulent flow and especially buoyancy effects on the turbulent fluctuation. etc. The verification of predicted results from the numerical study continues in the qualitative study. because of the lack of experimental data, which seems to be due to the difficulties in measuring the turbulent fluctuations in concentration or temperature fields. In this study, the computer program of Algebraic Stress Model has been developed to investigate the behaviours of two-dimensional surface buoyant jets with free surface boundary condition. The computational results are compared with published experimental data. By comparing these results with experimental data. it is found that this model can predict fairly well the flow characteristics of two-dimensional surface buoyant jets in the momentum-dominant region and buovancy-dominant region. Especially, it is proved that this model can predict the flow characteristics reasonably in buoyancy-dominant region stably stratified due to buoyancy effect.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.2
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• pp.109-116
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• 2005

3D Spatial Data, namely 3D Urban CG model express the building, road, river in virtual world and accumulate, manage the data in the GIS system. It is important infrastructure which expected in many usages. Recently 3D CG urban model needs much manual effort, time and costs to build them. In this paper, we introduce the integration of GIS, CG and automatic production of the $\lceil$3D Spatial Data Infrastructure$\rfloor$. This system make filtering, divide the polygon, generate the outlines of the GIS building map, design the graphic and property information and finally make automatic 3D CG models.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.3
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• pp.105-114
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• 2002

효율적인 난류 유동장 해석을 위해 CFDS 기법에 1개의 대수적 난류 모델과 2개의 1-방정식 난류 모델이 적용되었다. 대수적 난류 모델인 Baldwin-Lomax 난류모델과 1-방정식 난류 모델인 Baldwin-Barth, Spa lart-Allmaras 난류 모델을 비교하기 위해 2차원 유동에 대해서 2가지 경우, 3차원 유동에 대해서는 3가지 경우에 대해 해석하였다. CFDS 기법의 수치적 결과의 타당성은 실험치와의 비교를 통하여 입증하였다.