• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.23-26
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• 2010

본 논문에서는 유니버설 조인트의 동역학적인 해석을 위하여 오일러 각 순서에 의한 방법과 4원수에 의한 방법으로 운동방정식을 유도하였다. 원동축과 종동축의 회전은 물론 세차운동을 하는 회전축을 포함할 때 각 방법의 상이점을 발견하였다. 이러한 시스템의 동역학적 정식화를 바탕으로 한 수치 예제를 통하여 기존의 오일러 각 방법과 제시한 4원수 방법의 해석 결과를 비교하였다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1998.09a
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• pp.24-30
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• 1998

고도의 산업발달은 인간환경과 밀접한 하구와 해안의 오염을 심화시켜 최근 사회적 문제로 대두되고 있으며, 이에 오염물질의 이동을 예측하고 제어하려는 노력이 꾸준이 진행되어 왔다. 이 같은 노력은 수치모형을 이용한 수질관리 연구에도 많은 진전을 가지고 왔으며, 오일러적 모형, 라그랑쥐적 모형, 오일러-라그랑쥐 적 모형이 대표적이다. 오일러-라그랑쥐적 모형은 이류에 대해 라그랑쥐적 방법, 확산에 대해 오일러적 방법으로 해석함으로서 각 방법들의 장점을 취하여 수치적 진동, 수치적 확산이 적고 효율성이 뛰어나 최근 많이 연구되고 있다. (중략)

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.5
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• pp.475-482
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• 2008

This paper indicates that the use of Euler angles lacks in its consistency and exactness of analysis when it was applied to incorporate the rotational equation of motion for rotor systems by previous researcher. Kinetic energy and angular velocity are different from case to case depending on the way of choosing Euler angles and thus only the linear system has been investigated even though the rotor system has a very nonlinear behavior. A new methodology is applied by using both spherical coordinate and quaternion in the rotor rotation to overcome weaknesses of Euler angles and shows its superiority It is found through numerical examples that the use of quaternion will be a more useful and valid tool to derive the numerical model of the rotor system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.2
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• pp.183-189
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• 2010

This paper deals with the comparison of analysis methodologies by applying both Euler angle and quaternion to observe the kinematical behavior of the universal joint system used as an automotive drive-shaft. At first, conventional approaches are applied to predict a kinematical behavior by introducing only Euler angles into the universal joint system, but turns out to be lack in consistency and reliability of the analysis. Then to overcome this deficiency in numerical analysis a different methodology is proposed by using quaternion in this system. Its corresponding advantage is discussed in terms of kinetic energy, rotational velocity and rotational displacement. The application of quaternions in the numerical experiment is shown to be a more useful and valid way of establishing the ideal analytical model of the universal joint system.

• Journal of the KSME
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• v.52 no.12
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• pp.38-40
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• 2012

이 글에서는 지금까지 대부분 기계 제품을 만들고 발전시키는 데 사용되어 왔던 기계공학 지식이 우리 인체의 움직임을 연구하는 데 어떻게 쓰일 수 있는지 한 가지 연구 주제를 예를 들어 설명하였다. 재료역학 이론을 바탕으로 만들어진 요추 모델을 통해 외부힘과 상체의 각도에 따라 각 요추의 움직임이 어떻게 달라지는지 알아보았다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.8
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• pp.8-17
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• 2005

It is well known that preconditioning methods are efficient for convergence acceleration in the compressible low Mach number flows. In this study, the original Euler equations and three differently nondimensionalized preconditioning methods are implemented in two dimensional inviscid bump flows using the 3rd order MUSCL and DADI schemes as numerical flux discretization and time integration, respectively. The multigrid and local time stepping methods are also used to accelerate the convergence. The test case indicates that a properly modified local preconditioning technique involving concepts of a global preconditioning allows Mach number independent convergence. Besides, an asymptotic analysis for properties of preconditioning methods is added.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.41-46
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• 2001

The very large vessels like VLCC and container ship have been built recently and those vessels have smaller structural strength in comparison with the other convectional skips. As a result the fatigue destruction of upper deck occurs a frequently due to the springing phenomenon at the encountering frequencies. In this study, the hydrodynamic loads are calculated by three-dimensional source distribution method with the translating and pulsating Green function. A ship is longitudinally divided into 23 sections and the added mass, damping and hydrodynamic force of each section is calculated. focusing only on the vertical motion. Stiffness matrix is calculated by the Euler beam theory. The calculation is carried out for Esso Osaka.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.417-420
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• 2009

본 논문에서는 유니버설 조인트의 기구학적인 해석을 위하여 원동축이 평면 내에 존재할 경우와 그렇지 않은 경우에 대하여 종동축의 속도를 관찰하였다. 평면 내의 경우는 기존 이론값과 동일하나 평면 외의 경우는 유한회전의 순서에 따라서 독립적인 결과값을 가지게 된다. 이는 오일러 각의 순서를 달리하면 표현되는 속도가 다르기 때문이며 이러한 단점을 극복하기 위하여 원동축에 4원법을 적용하였다. 수치 예제를 통하여 기존의 방법과 제시한 방법을 비교하여 제시한 방법이 일관성 있는 결과를 제공함을 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.476-477
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• 2022

This study deals with rotation, which is one of the expression methods of motion used in the 3D development environment. Euler angle is a rotation method introduced by Leonhard Euler to display objects in three-dimensional space. Although three angles can handle all rotations in a three dimensional coordinate space, there are serious errors in this approach. If you rotate an object with Euler angles, you will face the problem of gimbal locks that cannot rotate under certain circumstances. In contrast to this, the method to rotate an object without a gimbal lock is the quaternion rotation with quaternion. Rather than a detailed mathematical proof of quaternion, it introduces what concept is used in the current 3D development environment, and applies it to camera rotation control to implement a rotating camera without a gimbal lock.

• The Journal of the Korea Contents Association
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• v.8 no.2
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• pp.27-32
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• 2008

In this paper, we propose an orientation tracking method and a digestion path model based on angular displacement. The proposed method expresses a capsule's orientation as 3-dimension vectors and its rotation angle. Errors in roll, pitch, and yaw representing capsule's orientation information is down to $1.6^{\circ}$. Using the proposed method we can measure a roll which is not Possible to be measured using the magnetic field method. We reduce algorithm complexity lower than a previous methods based on Euler angle.