• 한국음향학회지
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• 제15권6호
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• pp.47-51
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• 1996

실린더 운동방정식은 실린더 내에서 발생되는 소음 해석에 매우 중요하다. 그러므로, 지금까지 많은 학자들에 의해 실린더 운동방정식을 유도되었다[1]. 참고문헌[6]에서는, 새로 제안돈 실린더 운동방정식, Junger and Feit의 실린더 운동방정식 그리고 가정해에 의한 선형방정식으로, 실린더가 자유 운동을 할 때, 자유파수를 구하였다. 본 논문에서는 자유파수들의 분산곡선들을 이용하여, 두 실린더운동방정식을 비교하였고, 링주파수와 링확장주파수의 계산으로, 자유파수들의 분산곡선의 물리적인 의미를 부가하였다. 이 결과, 새로 유도된 실린더 운동방정식의 타당함을 보였다. 새로 제안된 실린더 운동 방정식을 이용하면, 산업현장에서, 실린더 내의 고체파에 대한 보다 정확한 분석을 할 수 있을 것으로 사료된다.

• 대한수학회지
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• 제44권2호
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• pp.443-453
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• 2007

We study the equation of a membrane with strong viscosity. Based on the variational formulation corresponding to the suitable function space setting, we have proved the fundamental results on existence, uniqueness and continuous dependence on data of weak solutions.

• Structural Engineering and Mechanics
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• 제24권5호
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• pp.543-560
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• 2006

In this paper, first, the equations of motion for a rectangular isotropic plate have been derived. This derivation is based on the Von Karmann theory and the effects of shear deformation have been considered. Introducing an Airy stress function, the equations of motion have been transformed to a nonlinear coupled equation. Using Galerkin method, this equation has been separated into position and time functions. By means of the dimensional analysis, it is shown that the orders of magnitude for nonlinear terms are small with respect to linear terms. The Multiple Scales Method has been applied to the equation of motion in the forced vibration and free vibration cases and closed-form relations for the nonlinear natural frequencies, displacement and frequency response of the plate have been derived. The obtained results in comparison with numerical methods are in good agreements. Using the obtained relation, the effects of initial displacement, thickness and dimensions of the plate on the nonlinear natural frequencies and displacements have been investigated. These results are valid for a special range of the ratio of thickness to dimensions of the plate, which is a characteristic of the Multiple Scales Method. In the forced vibration case, the frequency response equation for the primary resonance condition is calculated and the effects of various parameters on the frequency response of system have been studied.

• 대한수학회지
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• 제42권1호
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• pp.153-169
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• 2005

A fuzzy stochastic differential equation contains a fuzzy valued diffusion term which is defined by stochastic integral of a fuzzy process with respect to 1-dimensional Brownian motion. We prove the existence and uniqueness of the solution for fuzzy stochastic differential equation under suitable Lipschitz condition. To do this we prove and use the maximal inequality for fuzzy stochastic integrals. The results are illustrated by an example.

• 대한전기학회논문지
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• 제38권12호
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• pp.995-1006
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• 1989

로보트 매니퓰레이터가 컨베이어 상의 파트를 추적 하면서 작업을 수행하는 것은 작업 효율의 증가에 크게 기여한다. 본 논문은 컨베이어 상의 파트를 추적하기 위한 로보트 매니퓰레이터의 동작계획 알고리즘을 제안한다. 로보트 매니퓰레이터의 추적 동작은 밸트의 속도, 추적 시작 시간에서의 파트와 로보트 핸드의 위체이 의하여 결정된다. 이때 토크 및 관절 속도, 관절 가속도, 관절 저크의 제한범위가 모두 고려되며, 최소의 정착시간을 갖는 추적 궤적이 생성된다. 추적 해는 linearr quadratic tracking문제로 접근하여 구한다. 로보트매니퓰레이터의 동적 방정식은 파라메터의 함수 성능 지수를 최소화 하는 동적 방정식의 해는 동적 계획법에 의하여 구한다. ${\mu}-VAX_@$에 의한 시뮬레이션 결과를 제시한다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.291-298
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• 2003

The resonant column testing is a laboratory testing method to determine the shear modulus and the material damping factor of soils. The method has been widely used for many applications and its importance has been increased. Since the establishment of the testing method in 1963, the low-technology electronic devices for testing and data acquisition have limited the measurement to the amplitude of the linear spectrum. The limitations of the testing method were also attributed to the assumption of the linear-elastic material in the theory of the resonant column testing and to the use of the wave equation for the dynamic response of the specimen. For the better theoretical formulation of the resonant column testing, this study derived the equation of motion and provided its solution. This study also proposed the improved data reduction and analysis method for the resonant column testing, based on the advanced data acquisition system and the proposed theoretical solution for the resonant column testing system. For the verification of the proposed data reduction and analysis method, the numerical simulation of the resonant column testing was performed by the finite element analysis. Also, a series of resonant column testing were peformed for Joomunjin sand, which verified the feasibility, of the proposed method and showed the limitations of the conventional data reduction and analysis method.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1155-1162
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• 2023

The Korea Research Institute of Ships and Ocean Engineering (KRISO), which is developing the core technology for the buoyancy engine of underwater gliders, has developed a test module that can vertically ascend and descend with a buoyancy engine to verify the performance of the developed buoyancy engine. The independent test module was tested in a 15 metre deep pit in the Ocean Engineering Basin to verify its ability to ascend and descend. In order to test at a shallower depth than the real sea, it was necessary to know the negative buoyancy value during descent and the time at which the buoyancy engine would be activated. To do this, we solved the equation of motion in the vertical direction to obtain these values and applied them to the tank test. To validate the usefulness of solving the equation, we also compared the depth of descent over time measured in the test with the results calculated from the solution.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 봄 학술발표회 논문집
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• pp.111-118
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• 1996

Dynamic load models which show the practical behavior of truss bridge subjected to moving train load are presented. Three basically approaches are available for evaluating structural response to dynamic effects : moving force, moving mass, and influence moving force and mass. Simple warren truss bridge model is selected in this research, and idealized lumped mass system, modelled as a planar structure. In the process of dynamic analysis, the uncoupled equation of motion is derived from simultaneous equation of the motion of truss bridge and moving train load. The solution of the uncoupled equations of motion is solved by Newmark-$\beta$ method. The results show that dynamic response of moving mass and static analysis considering the impact factor specified in the present railway bridge code was nearly the same. Generally, the dynamic response of moving force is somewhat greater than that of moving mass. The dynamic load models which are presented by this study are obtained relatively adequate load model when apply to a truss bridge.

• 상하수도학회지
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• 제9권3호
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• pp.65-77
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• 1995

The kinetics of flocculation of heterodisperse suspension like those in water treatment plants and natural water system are usually described by the Smoluchowski equation, which incorporates collision frequency functions for particle collisions by Brownian motion, fluid shear, and differential sedimentation. These collisionfrequeney functions have been based on a rectilinear view of collisions, i.e., one that ignores short-range forces and changes in fluid motion as particles approach one another. In this research, a curvilinear approach, i.e., one that accounts for hydrodynamic forces and particle interaction in the collision of two different size particles is developed. Collision efficiency factors of each mechanism can be calculated by trajectory analysis (fluid shear and differential sedimentation) or the solution of diffusion equation (Brownian motion). The results are presented as a set of corrections to the rectilinear collision frequency functions for each mechanism.

• Selected Papers of The Society of Naval Architects of Korea
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• 제2권1호
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• pp.47-62
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• 1994

Herein the surge-heave-pitch motion of a ship in harbor has been analyzed within the framework of linear potential theory. The ship is assumed to be slender and moored at an arbitrary position in a rectangular harbor with a constant depth. The coast line is assumed to be straight. The ship and harbor responses to incident long waves are represented in terms of Green's function, which is the solution of tole Helmholtz equation satisfying necessary boundary conditions. An integral equation is obtained from matching condition between harbor and ocean solutions, and it is replaced by an equivalent variational form. Numerical results sallow that the ship motion can be highly amplified at the frequencies, where the harbor is resonated by the incident wave. At the resonant frequencies, the added mass for vertical motions becomes negative and the damping forte changes abruptly.