• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.1
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• pp.33-42
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• 2002

A method of automatic 3D tunnel modeling is proposed. The proposed method used the parametric representation of geometry and a hierarchical and relational data structure. These two bases provide the generalization and extension for 3D tunnel modeling. Especially, these two fundamentals ion the basis iota representing the characteristics of the tunnel structure for analysis. The constant-curvature characteristic is exploited to generate 3D mesh on the tunnel surface. This is attributed to the advantage that any 2D automatic mesh generation algorithm can be applied to 3D mesh modeling.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.55-58
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• 2005

Low resistivity zone is observed at the lower part of a CFRD (Concrete Face Rockfill Dam). Generally, CFRD tends not to have any saturated zone within the body, but the result of resistivity survey shows that it is possible for the dam to be saturated under 20m depth with water. The level of reservoir was under 10m from the crest. We suspect that this result may come from the wrong 2D inversion process ignoring the 3D geometry of dams. For the analysis of possibility of distortion by different geometry, we perform the 3D forward modeling for the dam and apply the 2D inversion process. And then we check the point of traditional interpretation of resistivity data. By the analysis, it is found that the result of 2D inversion process of 3D geometry of dams, seems to have deep relation with the reservoir level, and the complex 3D structure hide some internal electrical anomaly of dams from resistivity information.

• Journal of the Korean Geophysical Society
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• v.8 no.4
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• pp.211-214
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• 2005

Low resistivity zone is observed at the lower part of a CFRD (Concrete Face Rockfill Dam). Generally, CFRD tends not to have any saturated zone within the body, but the result of resistivity survey shows that it is possible for the dam to be saturated under 20m depth with water. The level of reservoir was under 10 m from the crest. We suspect that this result may come from the wrong 2D inversion process ignoring the 3D geometry of dams. For the analysis of possibility of distortion by different geometry, we perform the 3D forward modeling for the dam and apply the 2D inversion process. And then we check the point of traditional interpretation of resistivity data. By the analysis, it is found that the result of 2D inversion process of 3D geometry of dams, seems to have deep relation with the reservoir level, and the complex 3D structure hide some internal electrical anomaly of dams from resistivity information.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.632-634
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• 2003

4차원 지리정보시스템은 기존의 2차원 공간정보의 평면적인 정보구조가 가지는 한계를 극복하기위해 확장된 좌표계를 가진다. 추가된 좌표축은 공간 객체들의 높이 정보축과 시간 정보축을 포함한다. 이 연구에서는 OGC에서 제안하는 2차원 기하 클래스 구조를 수용하고 추가된 시공간 정보를 다룰 수 있는 4차원 기하 객체 모델을 정의하였다. 또한. 시간 일 공간 데이터에 대한 인덱스를 구성하였으며 4차린 지리정보시스템의 공간데이터 제공 서비스를 위하여 3차원과 4차원 시공간 연산 및 분석 기능을 구현하였다.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.187-197
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• 2008

While driving a highway, A driver gets lots of information through geometrical structure, traffic situation, signs on the road. He gets most of the information by visual sense. Acceleration or deceleration and driving direction depend on sight distance. Therefore, it's essential to secure a driver's sight distance for a safe drive. However, design guides of geometrical structure and sight distance suggest respective standards of horizontal and vertical alignment. They do not indicate quantitative standard of combined alignment. Currently, element separated on a two-dimensional projected plane are available, but they do not guarantee safe and pleasant design. I will use the existent model analysing three-dimensional sight distance through mathematical calculation and sort a variety of geometrical structure element and type. In these researches, we will look at how much three-dimensional sight distance is overestimated or underestimated compared to two-dimensional. I will develop a program which predicts traffic velocity on the curvature of two-lane provincial road. stopped sight distance and three-dimensional sight distance will be compared at a predicted drive velocity. I will suggest the way to evaluate road consistency.

• The KIPS Transactions:PartA
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• v.16A no.3
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• pp.153-158
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• 2009

Analysis of 3-dimensional (3D) protein structure plays an important role of structural bioinformatics. The protein structure visualization is the one of the structural bioinformatics and the most fundamental problem. As the number of known protein structure increases rapidly and the study of protein-protein interaction is prevalent, the fast visualization of large scale protein structure becomes essential. The fast protein structure visualization system we proposed is sophisticated and well designed visualization system using geometry instancing technique. Because this system is optimized for recent 3D graphics hardware using geometry instancing technique, its rendering speed is faster than other visualization tools.

• Journal of radiological science and technology
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• v.36 no.2
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• pp.157-163
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• 2013

Multileaf collimators whose Pb leaves are moving in two-dimensional directions have been used. We propose a different concept three-dimensional (3D) collimator with 3D shape that is automatically changeable to modulate the radiation dose even for complex tumors in real time. A voxel collimator, including a hinged Pb plane and a 3D assembly of many voxel collimators, was used. In each frame rotation axis, a motor, which was controlled by a circuit with field-programmable gate array (FPGA) board connected with computer, was operated according to a predetermined plan. Simulations of that, which are generally used for planning, were performed and compared with experimental results.

• Journal of KIISE:Software and Applications
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• v.31 no.11
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• pp.1543-1550
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• 2004

Modeling from images is a cost-effective means of obtaining 3D geometric models. These models can be effectively constructed from classical Structure from Motion algorithm. However, it's too difficult to reconstruct whole scenes using SFM method since general sites contain a very complex shapes and brilliant colours. To overcome this difficulty, the current paper proposes a new reconstruction method based on a moving Planar mirror. We devise the mirror posture instead of scene itself as a cue for reconstructing the geometry That implies that the geometric cues are inserted into the scene by compulsion. With this method, we can obtain the geometric details regardless of the scene complexity. For this purpose, we first capture image sequences through the moving mirror containing the interested scene, and then calibrate the camera through the mirror's posture. Since the calibration results are still inaccurate due to the detection error, the camera pose is revised using frame-correspondence of the comer points that are easily obtained using the initial camera posture. Finally, 3D information is computed from a set of calibrated image sequences. We validate our approach with a set of experiments on some complex objects.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.73-75
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• 2002

PDB에서 제공하는 단백질 3차원 고분자결정 구조에 대한 플랫파일은 인자들의 좌표, 서열정보, 실험정보 및 참조 정보가 포함된다. 이러한 정보를 포함하고 있는 플랫파일로부터 필수적인 구조정보 및 서열정보 등의 효율적인 검색을 위해서는 이러한 데이터를 추출하여 데이터베이스 구축이 요구되며 이 때 단백질 구조 및 서열 정보와 실험 및 탐조 정보의 관계에 대한 모델링이 중요하다. 따라서 이 논문에서는 PDB에서 제공하는 플랫파일들의 엔트리들을 분석하고 3차원 공간 객체의 기하적 특성을 갖는 단백질 3차 구조를 공간객체로 표현하고 공간객체 모델을 적용하여 모델링한다. 이렇게 함으로써 단백질 3차 구조 분자를 구성하는 인자 및 구조 정보 검색이 가능하며 위상 및 기하 연산자글 이용하여 단백질 구조 분석에 활용할 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.188-189
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• 2017

점진적 움직임 기반 구조(Incremental Structure from Motion)는 다양한 시점에서 촬영한 영상들을 하나 씩 점진적으로 추가하여 3차원 장면을 복원하는 방법이다. 3차원 구조 복원에 사용되는 영상 켤레들 중에는 불필요한 켤레들도 충분히 포함되어 있으므로 복원된 구조의 불안정성과 불필요한 영상 켤레 처리로 인한 성능 손실이 발생할 수 있다. 이 논문은 상대적으로 불필요한 영상 켤레를 입력 영상 집합에 맞게 적응적으로 제거하는 방법을 제안한다. 대응점 탐색 단계에서 기하학적 검증작업 전후로 총 두 번의 영상 켤레 제거가 실행되며, 통계적인 방법 및 기하학적으로 검증된 대응점 비율을 이용하여 문턱치를 결정한다. 실험 결과 3차원 복원 결과에 지장을 주지 않으면서 복원에 필요한 영상 켤레 개수를 효과적으로 줄일 수 있었다.