• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.234-239
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• 2003

A cylindrical shape object is widely used as a mechanical part and a water pipe or an oil pipeline which are of cylindrical shape are widely used in the infrastructure. In order to handling such objects automatically using a robot, the posture i.e. orientation in 3D space should be recognized. However, since there is no edge or vertex in the pipe, it is very difficult task for the robot. In this paper in order to guide the robot, two kind of algorithms which find the axis using the measured range data from the robot to the object surface are to be developed. The algorithms are verified using both the simulated range data and the measured one.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.11-15
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• 2009

This paper is concerned with the elastic buckling of thin-walled arches that are subjected to uniform bending. Nonlinear strain-displacement relations with the initial curvature are substituted into the second variation of the total potential energy to obtain the energy equation including initial curvature effects. The approximation for initial curvature effects that the bending normal strain distribution is linear across the cross section is applied consistently in the derivation process. The closed form solution is obtained for flexural-torsional buckling of arches under uniform bending and, it is compared with the previous theoretical results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6504-6510
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• 2015

Horizontally curved I-girders are subjected to not only bending moments but also torsional moments. The torsional moment of the plate girder is addition of St. Venant torsion and non-uniform torsion. In the flange of I-shaped plate girder, a kind of open-section, the normal stresses is not distributed uniformly due to the non-uniform torsion. Because of that, one of compression flange tip can be yielded faster than the flange of general straight girder. In other words, the flange local buckling strength is decreased when the girder has initial curvature. In this paper, the numerical analysis is conducted to investigate the average stresses in flange for curved girders. The subtended angle and slenderness ratio are taken as parameters.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.8-15
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• 2003

The cylindrical object such as a water pipe or an oil pipeline are widely used in the infrastructure. Those pipes should be inspected periodically by human or a robot. However, since there is no edge or vertex in the pipe, it is very difficult for the robot to navigate along the pipe. In this paper in order to guide the robot along the axis of the pipe, an algorithm which find the axis using the measured range data from the robot to the pipe wall is developed The algorithm is verified using both the simulated range data and the measured one.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.509-511
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• 1999

본 논문에서는 일반적으로 영역 기반형 분할방법보다 우수한 분할결과와 계산의 효율성을 가지는 경계선 기반형 방법의 하나인 scan line approximation 방법을 응용함으로써 경계선의 기하학적 해석이 가능하도록 하는 경계선 강도(edge intensity) 정보를 제공한다. 따라서 면 특성과 국부적인 면 특성인 면 법선과 면 곡률정보 없이 잡음에 강건하고 계산의 효율성에서 우수한 거리영상분할 방법을 제안한다. 합성 거리영상을 대상으로 scan line approximation 방법을 응용하여 얻어진 경계선을 경계선 그룹화의 영역 레이블링을 거쳐서 면 특징을 추출하였다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.1
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• pp.70-76
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• 2002

Unmanned vehicles have to decide their velocities suitable for the paths which should be generated by the vehicles themselves, based on the kinematic and dynamic aspects of vehicles. For this purpose, this paper is to propose a mathematical modeling of tuning trace for the cornering of an unmanned vehicle by using normal-tangent coordinates as well as extracting the characteristics of behavior for car drivers in cornering. In the proposed modeling, the limitations of velocity can be determined based on the knowledge that the handling of drivers means the control of radius of curvature. The proposed modeling can reduce computational load and generate turning angles and velocities suitable for the cornering of unmanned vehicles.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.5
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• pp.365-371
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• 2015

Hull plate consists of various types of curved plates and there also exists corresponding processing methods. Typically, curved plates can be divided into convex type and saddle type. Large amount of research has been conducted mainly focusing on application of processing method of convex type, saddle type and hybrid type, but research on determination and processing method application of the most difficult S-shaped curved plate that has inflection lines has not been carried out yet. In this paper, as the fundamental research of appropriate processing method application, a calculation method is proposed to calculate inflection lines on curved plates. In order to calculate inflection lines, normal curvature and information of fabricated curved plates should be utilized. We compare the workability of the fabrication for hull plate using inflection line.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.97-106
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• 2010

In this paper, lane and curvature detection algorithm based on the curve template matching method is proposed. To eliminate the perspective effect of the original image, the input image is transformed to a top view image. From this top view image, its edge image is created. To increase the accuracy of detection, a novel edge detection method, which shows a strength in lane detection, is proposed. In the first step, straight lanes are detected from the edge image, and then the Curve Template Matching(CTM) method is applied to detect the curved lanes and to find their curvatures. Since the proposed CTM method uses only the simple equations, such as line and circle equations, to detect the curved lane, the algorithm is simple. Moreover, we used the detected lane information in the previous frames to detect the current frame's lanes, the detection results become more reliable. The proposed algorithm has been tested in various road conditions (highway, urban street, night time highway, etc.). Experimental results show that the proposed algorithm can process about 70 frames per second with the successful lane detection rate over 95% and curvature detection rate about 90%.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.10
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• pp.421-426
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• 2019

In this paper, we propose a method to visualize the geometric features of the contact region between proteins in a protein complex. When proteins or ligands are represented as curved surfaces with irregularities, the property that the two surfaces contact each other without intersections is called shape compatibility. Protein-Protein or Protein-Ligand docking researches have shown that shape complementarity, chemical properties, and entropy play an important role in finding contact regions. Usually, after finding a region with high shape complementarity, we can predict the contact region by using residual polarity and hydrophobicity of amino acids belonging to this region. In the research for predicting the contact region, it is necessary to investigate the geometrical features of the contact region in known protein complexes. For this purpose, it is essential to visualize the geometric features of the molecular surface. In this paper, we propose a method to find the contact region, and visualize the geometric features of it as normal vectors and mean curvatures of the protein complex.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.512-515
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• 2010

본 논문에서는 등기하 해석법을 이용하여 설계의존형 하중조건을 갖는 구조물에 대한 형상 최적설계를 수행하였다. 유한요소법 기반 형상 최적설계는 CAD 모델과 해석 모델의 차이로 인해, 설계영역 매개변수화에 어려움이 있다. 등기하 해석법은 CAD 모델과 동일한 NURBS 기저 함수와 조정점을 해석에 이용함으로써 설계의 기하학적 변화를 해석모델에 직접적으로 표현할 수 있는 장점을 가진다. 하중조건이 설계 영역이 변화함에 따라 변하는 최적설계 문제의 경우, 정확한 설계 영역 표현은 법선 벡터, 즉 변화하는 하중의 방향과 곡률과 같은 고차항의 정보를 정확하게 표현할 수 있고, 따라서 목적함수를 최소 또는 최대화시키는 최적의 해로 이끌어 낸다. 유한요소법 또는 밀도법을 이용한 형상 최적설계에서 설계의존형 하중조건을 갖는 구조물의 문제를 푸는 경우, 최적설계가 진행됨에 있어 변화하는 경계의 부정확성 때문에 정확한 설계민감도를 얻기가 어려운 점이 있다. 본 논문에서는, 수치 예제를 통해 등기하 해석 기반의 형상 최적설계 방법론이 설계의존형 하중조건을 갖는 구조물 문제에서 수월성을 가짐을 확인하였다.