• Journal of Korea Game Society
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• v.19 no.1
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• pp.5-14
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• 2019

This paper presents a practical method to compute the closest approach distance of two ellipsoids in their inter-center direction. This is the key technique for collision handling in the dynamic simulation of rigid and deformable bodies approximated with ellipsoids. We formulate a set of equations with the inter-center distance and the contact point and normal for the two ellipsoids contacting each other externally. The equations are solved using fixed-point iteration and Aitken's delta-squared process. In addition, we introduce a novel stopping criterion expressed in terms of the error in distance. We demonstrate the efficiency and practicality of our method in various experiments.

• Journal of Korean Society for Geospatial Information Science
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• v.2 no.2 s.4
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• pp.143-151
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• 1994

3-D coordinates that result form GPS survey are not applied directly in korea because they are based on WGS 84 ellipsoid. Thus they must be transformed into longitude, latitude on the Bessel ellipsoid and orthometric height. Transformation parameters must be determined in order to perform the coordinate transformation. Also, coordinate transformation be preformed on longitude, latitude and ellipsoidal height. First estimation of Bessel geoidal height must be accomplished to acquire Bessel ellipsoidal height This paper suggests accuracy of coordinate transformation according to the estimation method of Bessel geoidal height. Also, This paper suggests that Bessel geoidal height have influence on the coordinates transformation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.685-688
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• 2005

In this study, an efficient algorithm for the numerical search of the geodesic path of the creeping wave on a doubly curved surface is developed. The ellipsoid as a doubly curved surface is studied because of its three dimensional nature in that it can be used to simulate the body of an aircraft, or a missile body. Numerical result of the geodesic path on an ellipsoid is given.

• Journal of the Korea Computer Graphics Society
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• v.8 no.4
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• pp.1-7
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• 2002

This paper presents a new approach for modeling human limbs shape from 3D scan data. Based on the cylindrical structure of limbs, the overall shape is approximated with a set of ellipsoids through ellipsoid fitting and interpolation of fit-ellipsoids. Then, the smooth domain surface representing the coarse shape is generated as the envelope surface of ellipsoidal sweep, and the fine details are reconstructed by constructing parametric displacement function on the domain surface. For fast calculation, the envelope surface is approximated with ellipse sweep surface, and points on the reconstructed surface are mapped onto the corresponding ellipsoid. We demonstrate the effectiveness of our approach for skeleton-driven body deformation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.69-76
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• 1994

In this paper, the characteristics of coordinate transformation between the WGS84 and the Bessel ellipsoids according to the assumed values of the geoidal height on Bessel ellipsoid at the geodetic datum origin of Korea were investigated. For this, based on GPS data of 11 control points in Chungnam and Chungbuk province, the mean shift values between ellipsoids were calculated in each case. The geoidal heights on the Bessel ellipsoid were modelled in the area and the coordinate transformation coefficients were derived, and then the accuracy of the transformed coordinates according to fluctuations in geoidal heights were studied.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.2
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• pp.137-143
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• 1999

The straight spatial distance or geodesic distance on WGS84 ellipsoid measured by GPS should be reduced on geoid to be used in Korean Geodetic System. The factors for this reduction are geoidal height and mean radius of the earth. On this study the effects of these factors on reducing distance were analyzed and the result showed that mean geoidal height should be multiplied by $1.6\times{10}^{-7}$ per unit distance for reducing geodesic distance on reference ellipsoid to that on geoid. Condsidering that the geoidal height on Bessel ellipsoid in Korea is -45 m in northeast and -75 m in middle west. It also showed that the difference of geodesic distance between on reference ellipsoid and on geoid is about 7-12 mm per km.

• Journal of Korea Game Society
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• v.19 no.6
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• pp.99-106
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• 2019

This paper addresses a method to compute the closest approach distance between two ellipsoids in their inter-center direction. This is the key technique for collision detection and response between ellipsoids. We formulate a set of conditions with the inter-center distance, the contact point and the contact normal vector of the two externally-contacting ellipsoids. The equations are solved robustly and efficiently using a hybrid of Newton's method and the bisection method with root bracketing. We demonstrate the robustness and efficiency of the proposed method in various experiments.

• Review of KIISC
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• v.16 no.3
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• pp.18-24
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• 2006

본 논문에서는 ONB에서의 유한체 연산 및 타원곡선 암호 연산기의 효율성을 비교하고자, Type-I, Type-II로 구분되는 ONB용 유한체 연산기와 polynomial 기저용 유한체 연산기를 구현하고 이를 비교 분석하였다. 이때 구현되는 유한체 연산기는 하드웨어 면적과 성능을 trade-off할 수 있도록 hybrid 타입의 연산기를 구현하였으며, ONB용 유한체 연산기 구현 결과를 polynomial 기저의 유한체 연산기 구현 결과와 비교하여 On에서의 타원곡선 연산의 효율성을 검증하였다.

• The Korean Journal of Rheology
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• v.10 no.2
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• pp.98-105
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• 1998

가공공정중 변형을 수반하게 되는 고분자제품은 대부분 고분자사슬의 배향을 갖게 된다. 이렇나 사슬배향은 제품의 기계적, 광학적, 그리고 전기적 특성에 매우 중요한 영향을 미치는 것으로 알려져있다. 지금까지 고분자사슬의 배향상태를 나타내기 위한 여러방법은 모두 배향의 중심축을이 알려져 있다는 가정하에 전개되었다, 그러나 복잡한 배향모드를 갖 는 고분자가공의 경우에 배향중심측이 실험축과 일치하지 않는 경우가 많다 따라서 본연구 에서는 일반적인 고분자의배향상태를 나타내는 방법에 대해 알아보고 실제 고분자 가공공정 에 적용을 위해 실험적으로 배향의 대칭축을 찾을 수 있는 접근방법을 제시하고자 하였다. 그 결과 결정성 고분자의 배향상태를 광각 x-선 회절 data를 이용한2차배향 tensor를 통해 배향 타원체를 구성할수있었다. 이를PETdustls 필름과 HDPE사출성형물에 적용해 본 결과 이들의 2차 배향 tensor가 타원체를 잘 구성함을 알수 있었다. 또한 주어진 고분자의 결정 면들에 관계없이 고유한 중심축을 지니고 있음을 확인할수 있었다. 이를 통해 복잡한 배향 모드를 갖는 경우에 본연구에서 제안한 x-타원체를 통해 결정의 배향중심축을 효과적으로 찾을수 있음을 알수 있었다.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.119-126
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• 2018

In this study, In this study, the Datum Level-based hydrography surveying system and the ellipsoid-based system were analyzed to acquire more consistent depth data. For the study, the ellipsoid-based surveying for hydrography was conducted twice for the same track line. And the depth was calculated by correcting rise and fall of water level (water level change by tidal energy and other marine environmental energies) respectively by the traditional water level correction method and ellipsoidally referenced water level correction method. there is able to check that Ellipsoid-based hydrographic surveying data is more improved than Datum Level-based hydrographic surveying data in aspect of level difference phenomenon in the same area (surveying line). This result shows that if the Ellipsoid-based hydrographic surveying is performed, the sea level change (tidal energy and other marine environmental energy) of the survey area in real time could be reflected to more consistent generating bathymetric data.