• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.2
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• pp.121-131
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• 1986

The stiffness matrix of circularly curved frame elements including the warping effects is formulated by the solutions of vlasov's differential equations, and the procedure for the elastic static analysis of curved girder systems by the displacement method is presented. The validity of this method has been demonstrated by comparing the analysis results with other solutions. And if the tangential lines of the two frame element axes connected at any nodal point coincide, the transformation to the global coordinate system can be omitted when we analyze the structures consisting of circularly curved elements. The theory introduced in this thesis can be applied with sufficient accuracy to the structures built up with horizontally circular curved frame elements which have closed or open cross sections and are symmetric to the axis perpendicular to the plane of the curvature, such as prestressed concrete box girder bridges.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.627-629
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• 2017

There are a lot of research results on the problem of finding the union and intersection of n rectangles on a plane. Lipski와 Preparata(1981) presented a sequential algorithm with O(nlogn) time and O(nlogn) space for the problem of finding the union of rectangles whose sides are parallel to the coordinate axes[1]. Alevizos(2013) presented an improved O(nlogn) time and O(n) space algorithm for the same problem[2]. In this paper, we consider the problem of finding the union of iso-oriented rectangles such that the intersection of them is not an empty set. In this case, the union of the rectangles becomes a connected area, that is, an orthogonal polygon. In this paper, we propose a parallel algorithm that solves this problem in constant time in a reconfigurable mesh(in short, RMESH) model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1624-1630
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• 2019

With the increase in there are smart devices penetration around the world, services related to exercise checks are attracting attention. However, there is existing exercise amount measurement service does not use the altitude information, or because the use of an algorithm that does not corrected the GPS altitude error is not accurate movement distance provided have a problem. Therefore, in this paper, to improve the existing problems, Kalman-filter-based user movement distance measurement algorithm is designed and implementation of improved by using the Kalman-filter based GPS and barometric altimeter sensor fusion algorithm to improve the altitude value the accuracy and of calculate the coordinate plane distance. As a result of comparing the designed and implementation of algorithm with the existing algorithms, it is confirmed that the proposed algorithm improves the accuracy by about 2.17%.

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.388-397
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• 2005

The purpose of this study was to redefine the cephalometric landmarks in three-dimensional (3D) images, which are used in orthodontic cephalometric radiography, and to evaluate the reproducibility of each landmark for 3D cephalometric analysis. Eighteen CT scans were taken at the Department of Diagnostic Radiology at Seoul National University Dental Hospital and manipulated with V works 4.0(Cybermed Inc., Seoul, Korea). The coordinate system was established using 7 reference points, with no more than 4 points on the same plane. These 7 points were generated as a volume model, the voxel size of which was 4 by 4 by 2 (threshold value=639). The cephalometric landmarks were selected at the multiplanar reformation (MPR) window on the volume mode of V works 4.0. The selected landmarks were exported to V surgery (Cybermed Inc., Seoul, Korea) for the calculation of coordinate values. All the data were taken twice with a lapse of 2 weeks by one investigator The reproducibility of each landmark was $0.17\~1.21mm$ in the x axis, $0.30\~1.53mm$. In the y axis, and $0.27\~1.81mm$ in the z axis. In all three axes, the range of error was similar. These error ranges were acceptable with regards to the pixel space and slice thickness. The most reproducible points were 1 points which were selected on the basis of the volume model. The least reproducible points were J points that were defined by sutures.

• Ecology and Resilient Infrastructure
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• v.8 no.2
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• pp.88-96
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• 2021

In surface image velocimetry, a wide area of a river is photographed at an angle to measure its velocity, inevitably causing image distortion. Although a distorted image can be corrected into an orthogonal image by using 2D projective coordinate transformation and considering reference points on the same plane as the water surface, this method is limited by the uncertainty of changes in the water level in the event of a flood. Therefore, in this study, we developed a tilt image correction technique that corrects distortions in oblique images without resetting the reference points while coping with changes in the water level using the geometric relationship between the coordinates of the reference points set at a high position the camera, and the vertical distance between the water surface and the camera. Furthermore, we developed a distortion correction method to verify the corrected image, wherein we conducted a full-scale river experiment to verify the reference point transformation equation and measure the surface velocity. Based on the verification results, the proposed tilt image correction method was found to be over 97% accurate, whereas the experiment result of the surface velocity differed by approximately 4% as compared to the results calculated using the proposed method, thereby indicating high accuracy. Application of the proposed method to an image-based fixed automatic discharge measurement system can improve the accuracy of discharge measurement in the event of a flood when the water level changes rapidly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1126-1133
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• 2013

For providing personalized intelligent services to users, 3 dimensional indoor positioning technology to recognize the position of person and equipment becomes important. In this paper, the acoustic signal generated from the proliferated smart phone is received from the 5 microphones equipped in the front panel of 3D positioning system, and the two proposed methods estimate the 3D coordinate of the smart phone, and finally it is verified using the implemented experimental system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.6
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• pp.66-78
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• 1978

An assembly package program is developed for a computerize4 operation of a drilling machine system utilizing a microprocessor. Different drilling instruction requires merely the input of different sets of input data. To make pulse motors to follow their input pulse trains with fidelity, an optimum start-stop rate matrix is proposed, whose elements are determined according to the pulse motor torque and the load inertia of the mechanical system composed of a workpiece and a worktable.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.528-530
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• 1996

Because of the convenience of variable speed control and proportion of input current and torque, DC servo motor has been used as an actuator. With increasing development speed of robot and factory automation machinery, the actuator of excellent control characteristics is demanded. In this paper, The control characteristics of DC servo motor is tested by Fuzzy control with microprocessor and DC servo motor controller is designed for drive of the cartesian coordinate type robot. The control characteristics experimentation is realized to one axis position, two axes coordinate and circular motion control by experimental equipments.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.05a
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• pp.195-198
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• 2002

본 논문에서는 영상 해석 알고리즘의 하나인 원형 패턴 벡터 알고리즘과 퍼지 추론을 사용하여 손가락으로 커서를 제어하는 인터페이스를 구현하였다. 최대 원형 이동법을 이용하여 물체의 무게 중심점을 찾아서 그 점에서 원형 패턴 알고리즘을 적용하면 외곽가지 거리 스펙트럼을 추출할 수 있다. 손에 대한 조건을 제시하여 일치하는 스펙트럼이 추출되면 손으로 인식하게 하였다. 커서의 방향제어는 크게 수평 방향과 수직 방향으로 나눌 수 있다. 커서의 수평 방향은 거리 스펙트럼에 의해 지시 손가락 부분을 찾아서 평면 좌표로 해석하여 제어 하였고, 커서의 수직 방향은 최대 원형의 크기와 손의 최대 크기를 입력 받아 퍼지 추론하여 커서의 위치를 제어 하였다. 퍼지 추론을 이용함으로써 기존의 불연속적인 커서의 수직 방향 제어를 좀 더 유연하고 연속적으로 제어 할 수 있었다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.547-550
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• 2006

본 연구는 지적도면의 효율적인 3차원 위치정보를 구축하기 위하여 수치지도로부터 표고자료를 추출한 후 Kriging, TIN, IDW 보간기법을 적용하여 보간기법별 수치표고모델을 제작하였다. 구축된 수치표고모델를 이용하여 각각의 수치정사영상을 생성하고 수치지적도면과의 중첩 기법을 적용하여 평면위치(x, y)는 연속지적도 상에서 획득하고 높이값(z)은 수치정사영상상에서 획득 지적도면의 3차원 좌표를 구축하였다. 수치지도 DEM을 활용한 지적도면의 3차원 위치정보 구축을 위한 효율적이고 경제적인 방안을 제시하였다.