• 한국자동차공학회논문집
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• 제21권2호
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• pp.122-130
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• 2013

Rail geometries such as cant, grade and curvature can be easily represented by means of a track coordinate system. In this analysis, in order to derive a dynamic and constraint equation of a wheelset, the track coordinate system is used as an intermediate stage. Dynamic and constraint equations of railway vehicle bodies except the wheelset are written in the Cartesian coordinate system as a conventional method. Therefore, whole dynamic equations of a railway vehicle are derived by combining wheelset dynamic equations and dynamic equations of railway vehicle bodies. Constraint equations and constraint Jacobians are newly derived for the track coordinate system. A process for numerical analysis is suggested for the derived dynamic and constraint equations of a railway vehicle. The proposed dynamic analysis of a railway vehicle is validated by comparison against results obtained from VI-RAIL analysis.

• 한국소음진동공학회논문집
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• 제16권6호
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• pp.643-650
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• 2006

This paper is concerned with the vibration analysis of a simply-supported rectangular plate with a circular cutout. Even though there have been many methods developed for the free vibration of the rectangular plate with a rectangular cutout, very few research has been carried out for the rectangular plate with a circular cutout. In this paper, a new methodology called independent coordinate coupling method, which was developed to save the computational effort for the free vibration analysis of rectangular plate with a rectangular cutout, is applied to the case of circular cutout. The independent coordinate coupling method employs the global coordinate system for the plate and the local coordinate system for the cutout. In the case of the rectangular plate with a circular cutout, the global coordinate system is the Cartesian coordinate system and the local coordinate system is the polar coordinate system. By imposing the compatibility condition, the relationship between the global coordinates and the local coordinates is derived. This equation is then used for the calculation of the mass and stiffness matrices resulting in eigenvalue problem. The numerical results show the efficacy of the proposed method.

• 대한기계학회논문집A
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• 제21권8호
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• pp.1311-1321
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• 1997

In multibody dynamics, differential and algebraic equations which can satisfy both equation of motion and kinematic constraint equation should be solved. To solve these equations, coordinate partitioning method and constraint stabilization method are commonly used. In the coordinate partitioning method, the coordinates are divided into independent and dependent and coordinates. The most typical coordinate partitioning method are LU decomposition, QR decomposition, and SVD (singular value decomposition). The objective of this research is to find an efficient coordinate partitioning method in the dynamic analysis of flexible multibody systems. Comparing two coordinate partitioning methods, i.e. LU and QR decomposition in the flexible multibody systems, a new hybrid coordinate partitioning method is suggested for the flexible multibody analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1177-1182
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• 2006

This paper is concerned with the vibration analysis of a simply-supported rectangular plate with a circular cutout. Even though there have be en many methods developed for the free vibration of the rectangular plate with a rectangular cutout., very few research has been carried out for the rectangular plate with a circular cutout. In this paper, a new methodology called independent coordinate coupling method, which was developed to save the computational effort for the free vibration analysis of rectangular plate with a rectangular cutout, is applied to the case of circular cutout. The independent coordinate coupling method employs the global coordinate system for the plate and the local coordinate system for the cutout. In the case of the rectangular plate with a circular cutout, the global coordinate system is the Cartesian co ordinate system and the local coordinate system is the polar coordinate system. By imposing the compatibility condition, the relationship between the global coordinates and the local coordinates is derived. This equation is then used for the calculation of the mass and stiffness matrices resulting in eigenvalue problem. The numerical results show the efficacy of the proposed method.

• 응용통계연구
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• 제21권4호
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• pp.695-704
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• 2008

평행좌표그림은 다변량자료를 시각화하는 하나의 방법이다. 평행좌표그림은 4차원 이상의 직각좌표계 표시의 어려움을 극복할 수 있는 그림이다. 그러나 변수 축의 배열에 따라 같은 자료에 대하여도 다른 해석이 가능하다. 변수 선택 문제를 해결하는 한 가지 방법으로서 우리는 정다각기둥평행좌표그림을 제안할 수 있다.

• 한국운동역학회지
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• 제20권2호
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• pp.117-127
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• 2010

The axes of upper forearm coordinate system have been considered as principal axis of each segment which was component of elbow joint. The purpose of this study was to verify whether the mean direction(principal axis) of instantaneous axes of rotation for pure flexion/extension motion coincided with the flexion/extension axis of upper forearm coordinate system. The same procedure was done for pronation/supination motion. Furthermore, it was tested indirectly that there was an interaction effect between the two rotational motions. The results showed that most segment coordinate axes statistically were not consistent with the mean directions of flexion/extension and pronation/supination axes of rotation. From the results, it would be concluded that the ISB coordinate systems was proved to be a little valid for human movement analysis. There also was an effect of pronation/supination angles on flexion/extension motion.

• 응용통계연구
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• 제9권1호
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• pp.45-52
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• 1996

자료의 구조와 특징을 파악하기 위한 탐색적 자료분석을 행할 때 유용한 수단으로 통계 그래픽스가 이용된다. 평행좌표그림(parallel coordinate plot)을 통계 그래픽스의 한 방법인 동적 그래픽스로서 이용하기 위하여 동적 평행좌표그림이 쓰이는데, 이 도구를 이용하면 3차원 이상의 다차원 자료를 동적 그래픽스로 표현, 분석할 수 있다. 본 논문에서는 하나의 동적 평행좌표그림을 제시하고, 자료분석의 예를 보였다.

• 대한기계학회논문집
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• 제19권3호
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• pp.806-819
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• 1995

A study of radiative heat heat transfer has been done in the non-orthogonal coordinate system utilizing the finite volume method and the P.1 approximation. Radiation of absorbing, emitting and scattering media in a concentric annulus has been solved using the non-orthogonal coordinate and the calculations were compared with the existing results. The results obtained from the analysis using the finite volume method are in good agreement with the existing calculations for all optical thicknesses. It was also shown that for only optically thick cases, P-1 approximation can be used in a non-orthogonal coordinate. Convective heat transfer analysis has been carried out to obtain the temperature fields in a cross flow around a circular cylinder and the finite volume method was applied in the non-orthogonal coordinate system to analyze radiative heat transfer. Effects of the optical thickness, the ratio of the surface temperature of the cylinder tot he free stream temperature, and the scattering albedo on radiation have been presented.

• 한국군사과학기술학회지
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• 제11권6호
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• pp.63-73
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• 2008

The helicopter position, heading data and the direction finding data of ESM are essentially required to compensate the parallax and analyze the direction finding accuracy of heliborne ESM in flight test phase. In the case of the long test range compared with small platform like as LYNX helicopter and Jisim Island test site, the parallax compensation for direction finding accuracy calculation and GPS position error can be neglected. In this paper, the direction finding accuracy on the basis of helicopter propeller was calculated by coordinate changing between helicopter and transmitting antenna from WGS84 coordinate to navigation coordinate using helicopter position and direction finding data.

• 한국정보과학회논문지:소프트웨어및응용
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• 제27권4호
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• pp.448-462
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• 2000

자연언어처리에 있어서 병렬구문은 분석의 복잡성, 단어의 애매성, 서술어 생략 등에 따른 처리의 어려움을 내포하고 있다. 본 논문에서는 한국어에서 발생하는 병렬문의 통사적 특징을 능력문법 (competence grammar)의 입장에서 접근하고 분석된 결과를 기반으로 하여 한국어 병렬문 해석을 위한 결합범주문법 (Combinatory Categorial Grammar)을 제안한다. 제안된 결합범주문법을 사용해서 병렬문에 대한 각각 다른 수준의 통사적, 의미적, 문맥적 정보들이 사전에 어휘적으로 통합될 수 있고 통합된 정보를 이용하여 통사적, 의미적, 문맥적 분석들이 각각 다른 수준의 처리를 거치지 않고 동시에 점진적으로 유도될 수 있음을 보인다. 유도된 정보들을 통해 일반적으로 한국어 병렬문의 주된 기능이라고 생각되는 두 문장이 가지는 정보를 대조, 비교하는 기능이 표현될 수 있음을 보인다. 말뭉치를 분석하여 병렬문이 한국어 처리에서 차지하는 비중과 제시한 문법으로 처리할 수 없는 문형들에 대한 논의를 제공한다.