• Journal of Astronomy and Space Sciences
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• v.12 no.1
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• pp.78-89
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• 1995

We solved n-body problem about 9 planets, moon, and 4 minor planets with relativistic effect related to the basic equation of motion of the solar system. Perturbations including flgure potential of the earth and the moon and solid earth tidal effect were considered on this relativistic equation of motion. The orientations employed precession and nutation for the earth, and lunar libration model with Eckert's lunar libration model based on J2000.0 were used for the moon. Finally, we developed heliocentric ecliptic position and velocity of each planet using this software package named the SSEG (Solar System Ephemerides Generator) by long-term (more than 100 years) simulation on CRAY-2S super computer, through testing each subroutine on personal computer and short-time(within 800 dyas) running on SUN3/280 workstation. Epoch of input data JD2440400.5 were adopted in order to compare our results to the data archived from JPL's DE 200 by Standish and Newhall. Above equation of motion was integrated numerically having 1-day step-size interval through 40,000 days (about 110 years long) as total computing interval. We obtained high-precision ephemerides of the planets with maximum error, less $than\pm2\times10^{-8}AU(\approx\pm3km)$ compared with DE200 data (except for mars and moon).

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.354-359
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• 2013

일반적으로 건축물의 설계시 풍동 실험을 통한 풍환경의 평가를 수행하고 있으며, 이는 환경 영향 평가법에서 정한 건축 사업 시행 시 수반되어야 할 자연환경, 생활환경 그리고 사회경제환경의 영향 평가의 일환으로 실시되고 있다. 그러나, 풍동 실험의 경우 여러 가지 현실적 제약조건으로 설계와 실험의 피드백 (Feedback)이 원활하지 못하며, 특히 대상 건축물이 공장과 같이 대기 오염원이 되는 경우 실험은 더욱 어려운 형편이다. 이에 대한 보완책으로 전산 유체 역학을 이용한 건축물의 풍압 해석에 의한 풍하중 추정이나 인접 지형-지물의 영향을 고려한 건축물 주위의 풍환경 평가가 있다. 전산 모사에 의해 풍동 실험의 미비점을 보완하고, 보다 상세한 정보를 확보함으로써 건축물의 구조적 안전성의 증대와 환경 피해 감소를 기할 수 있다. 그러나 복잡한 지형-지물이나 건축물 주위의 풍환경에 대한 전산 모사는 주로 두 가지의 기술적 어려움을 수반하게 되다. 그 중 하나는 고정 경계면을 이루는 형상의 복잡성으로 인해 기존에 많이 이용하고 있는 Body-fitted 격자계를 이용하는 경우, 격자 생성 과정이 매우 복잡하고 어려울 뿐 만 아니라 생성된 격자가 주로 비정렬 (unstructured) 특성을 갖게 되어 수치해석 과정의 효율을 저하시키는 요인이 되며, 격자의 형상도 수치해석의 수렴성을 저하시키는 예가 많다. 다른 어려움으로 풍환경은 전형적인 난류 유동장으로서 난류의 전산 해석은 아직도 해결하지 못한 부분이 많다는 점이다. 이에 본 논문에서는 복잡한 지형-지물이나 건축물의 풍하중과 풍환경의 전산 모사 기술 확보를 위하여 수행중인 연구의 일환으로 물체 형상의 기하학적 복잡성의 극복을 위한 가상경계법 (Immersed Boundary Method)과 난류 유동장의 물리적 엄밀성을 높이기 위한 다와동 모사 (Large Eddy Simulation)을 이용한 물체 형상과 무관한 유동장 해석 기술 개발에 대하여 다루고자 한다. 먼저 최근에 유동 해석에 이용되는 방법인 가상경계법(IBM)은 물체를 포함한 전체 전산 영역을 직교 좌표계에 의해 이산화하고, 유동장내 존재하는 물체의 표면에서의 점착 조건을 만족시키기 위하여 지배 방정식에 적절한 외력을 추가로 고려하는 방법이다. 본 연구에서는 가상경계법을 이용하여 경계층에 위치한 건물 형상의 각진 물체 주위 사이에 형성되는 공동 내부의 비정상 유속 및 압력에 대한 전산 해석을 수행하고, 풍상측 전면에 형성되는 경계층에 의한 영향을 분석하였다.

• Journal of Biomedical Engineering Research
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• v.24 no.3
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• pp.183-192
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• 2003

A transformation methode of the chromaticity coordinates was proposed to calibrate the measured data obtained by a urine analysis system which implemented in our previous study. Generally. the reacted color of a reagent strip by urine analysis system often exhibit the color distortions due to nonlinear characteristics of the various devices that is the optic module mechanism. hardware, and surround circumstance. A color correction method for minimizing the color distortion play a few role in maintaining high accuracy and reproduction of the urine analysis system. In this work, we used the compensation method such as the shading correction, the characteristic curve extraction of RGB color by means of third order spline interpolation, and linear transformation using a reference color. In addition, 1931 CIE XYZ color space was used to compensate the color of the measured data by a standard reference system as colorimeter. A compensation matrix was obtained so that the output values of the urine analysis system is nearly equal to that of a standard reference system for identical color sample. Color correction obtained by a urine analysis system which implemented in our previous study exhibited a good color accuracy when it was compared with the reference data. Observed result from an experiments on ten items or a urinalysis strip that color difference or between two urine analysis system was 1.28.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.51-62
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• 1993

A computational program ［TDET］ of the particle transport equation is developed on radiation shielding problem in two-dimensional cartesian geometry based on the discrete element method. Not like the ordinary discrete ordinates method, the quadrature set of angles is not fixed but steered by the spatially dependent angular fluxes. The angular dependence of the scattering source term in the particle transport equation is described by series expansion in spherical harmonics, and the energy dependence of the particles is considered as well. Three different benchmark tests are made for verification of TDET : For the ray effect analysis on a square absorber with a flat isotropic source, the results of TDET calculation are quite well conformed to those of MORSE-CG calculation while TDET ameliorates the ray effect more effectively than S$_{N}$ calculation. In the analysis of the streaming leakage through a narrow vacuum duct in a shield, TDET shows conspicuous and remarkable results of streaming leakage through the duct as well as MORSE-CG does, and quite better than S$_{N}$ calculation. In a realistic reactor shielding situation which treats in two cases of the isotropic scattering and of linearly anisotropic scattering with two groups of energy, TDET calculations show local ray effect between neighboring meshes compared with S$_{N}$ calculations in which the ray effect extends broadly over several meshes.eshes.

• Progress in Medical Physics
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• v.10 no.2
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• pp.63-71
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• 1999

For the purpose of utilization in 3-D conformal radiotherapy and whole body radiosurgery, the Whole Body 3-Dimensional Topographic Radiation Therapy System has been developed. Whole body frame was constructed in order to be installed on the couch. Radiopaque catheters were engraved on it for the dedicated coordinate system and a MeV-Green immobilizer was used for the patient setup by the help of side panels and plastic rods. By designing and constructing the whole body frame in this way, geometrical limitation to the gantry rotation in 3-D conformal radiotherapy could be minimized and problem which radiation transmission may be altered in particular incident angles was solved. By analyzing CT images containing information of patient setup with respect to the whole body frame, localization and coordination of the target is performed so that patient setup error may be eliminated between simulation and treatment. For the verification of setup, the change of patient positioning is detected and adjusted in order to minimize the setup error by means of comparison of the body outlines using 3 CCTV cameras. To enhance efficiency of treatment procedure, this work can be done in real time by watching the change of patient setup through the monitor. The method of image subtraction in IDL (Interactive Data Language) was used to visualize the change of patient setup. Rotating X-ray system was constructed for detecting target movement due to internal organ motion. Landmark screws were implanted either on the bones around target or inside target, and variation of target location with respect to markers may be visualized in order to minimize internal setup error through the anterior and the lateral image information taken from rotating X-ray system. For CT simulation, simulation software was developed using IDL on GUI(Graphic User Interface) basis for PC and includes functions of graphic handling, editing and data acquisition of images of internal organs as well as target for the preparation of treatment planning.

• Journal of the Korean Geographical Society
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• v.29 no.4
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• pp.438-449
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• 1994

This paper focuses on recontextualizing geography curriculum, i.e. examining recent changing aspects in three geography curriculum locators-society, student and discipline of geography-and searching future directions of geography curriculum in light of such changes. For conciliation and reflection of changing aspects of each locators, this paper dealt with social issues and societal changes in terms of locator of society, increased concern to student and development of cognitive science in terms of students, and challenging views on science and the meaning of epistemological changes in geography in terms of discipline. As a result, three future directions in geography curriculum are searched : issue-based geography curriculum, thinking geography curriculum, geography curriculum toward equity and accessbility.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.3
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• pp.311-321
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• 2009

The Nation Geodetic Reference System which presents a consistent location standard used in creating a map or developing national land is defined and managed by the law in a nation. Each nation had used its own geodetic system created by astronomical surveying until recently, when Geodetic Reference System(World Geodetic Reference System) has been developed and used to progress in space and satellite geodetic technologies. Korea also amended its geodetic law in December 2001, converting its national geodetic system whose reference an oval figure is Bessel ellipsoid into the World Geodetic Reference System which uses GRS80 ellipsoid as reference ellipsoid. Accordingly, the National Geography Information Institute improved law and systems related to the change for the effective conversion from its national geodetic system into the World Geodetic Reference System. In addition National geographic information institute of the results of various studies is drawn to the World Geodetic Reference System for switching technology-met some of the institutional foundation Despite of accordance with formalities, National geographic information institute, Ministry of Land, Transport and Maritime Affairs and some local government of the World Geodetic Reference System, and local government has or has not spread in public institutions. Therefore, in order to promote the switch to the World Geodetic Reference System, it is required to analyze current technical and institutional problems and obstacles of the switch to the World Geodetic Reference System and to present the resolutions and to establish policy to achieve them. Accordingly, for the promotion of the switch to the World Geodetic Reference System, this study analyzed the results of previous studies, the current state of the switch to the World Geodetic Reference System and the problems of the switch, and then offered technological and institutional supplements. Furthermore, it standardized the subject and type of the conversion, defined the scope of the tasks of the National Geographic Information Institute and its related organizations, and presented the policy direction for the overall use of the World Geodetic Reference System by 2010.

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.345-354
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• 2005

A mobile manipulator - a serial connection of a mobile robot and a task robot - is a very useful system to achieve various tasks in dangerous environment, because it has the higher performance than a fixed base manipulator in terms of its operational workspace size as well as efficiency. A method for estimating the position of an object in the Cartesian coordinate system based upon the geometrical relationship between the image captured by 2-DOF active camera mounted on mobile robot and the real object, is proposed. With this Position estimation, a method of determining an optimal path for the mobile manipulator from the current position to the position of object estimated by the image information using homogeneous matrices. Finally, the corresponding joint parameters to make the desired displacement are calculated to capture the object through the control of a manipulator. The effectiveness of proposed method is demonstrated by the simulation and real experiments using the mobile manipulator.

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.445-454
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• 2013

By using the radio propagation prediction of Rec. ITU-R P.1546, geographic information system, and S-I plane, we presented the methodology of interference analysis based on the minimum coupling loss, and also suggested the local coordinate system for calculating azimuth and elevation angles between the victim receiver and the interferer for an arbitrary antenna pattern. To check the presented algorithm, the map with the land-sea mixed area was taken for the given area of $80{\times}60[km^2]$ as real geography information. Field strength, path profile, and protection ratio with maximum allowable interference level have been illustrated for radar and fixed wireless system for the assumed frequency. In addition interference power of the victim receiver was calculated asa function of azimuth and elevation angles of the interferer. The developed methodology of interference analysis in the VHF and UHF bands can be actually applied to assess interoperability as well as compatibility in the civil or military applications.

• The Korean Journal of Applied Statistics
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• v.31 no.3
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• pp.353-366
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• 2018

This study uses mixed-effects models to predict thigh soft tissue artefact (STA), relative movement of soft tissue such as skin to femur occurring during hip joint motions. The random effects in the model were defined as STA and the fixed effects in the model were considered as skeletal motion. Five male subjects without musculoskeletal disease were selected to perform various hip joint rotational motions. Linear mixed-effects models were applied to markers' position vectors acquired from non-invasive method, photogrammetry. Predicted random effects showed similar patterns of STA among subjects. Large magnitudes of STA appeared on the points near the hip joint regardless of sides; however, small values appeared on the distal anterior.