• 한국해양공학회지
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• 제30권6호
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• pp.458-467
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• 2016

In this paper, a strongly coupled method for investigating the interaction between a cable and tow-fish is presented. The nodal position finite element method was utilized to analyze the nonlinear cable dynamics, and 6DOF equations of motion were employed to describe the 3D rigid body motion of the tow-fish. Combining cable and tow-fish systems into a single formulation allowed the two nonlinear systems to be strongly coupled into a unified nonlinear system. This strongly coupled system was numerically integrated in the time domain using a predictor/multi-corrector Newmark algorithm. To demonstrate the validity, efficacy, and applicability of the current approach, two different scenarios (virtual and sea trial) were simulated, and the simulation results were validated using the physical plausibility and the sea trial test.

• 대한조선학회논문집
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• 제53권5호
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• pp.388-399
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• 2016

A motion analysis of an underwater towed cable is a complex task due to its nonlinear nature of the problem. The major source of the nonlinearity of the underwater cable analysis is that the motion of the cable involves large rigid-body motion. This large rigid-body motion makes difficult to use standard displacement-based finite element method. In this paper, the authors apply recently developed nodal position-based finite element method which can deal with the geometric nonlinearity due to the large rigid-body motion. In order to enhance the stability of the large-scale nonlinear cable motion simulation, an efficient time-integration scheme is proposed, namely predictor/multi-corrector Newmark scheme. Three different predictors are introduced, and the best predictor in terms of stability and robustness for impulsive cable motion analysis is proposed. As a result, the nonlinear motion of underwater cable is predicted in a very efficient manner compared to the classical finite element of finite difference methods. The efficacy of the method is demonstrated with several test cases, involving static and dynamic motion of a single cable element, and also under water towed cable composed of multiple cable elements.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.705-710
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• 2003

Many papers have studied computer simulations of elastic bodies undergoing large deflections and large deformations. But there have not been many attempts to check the validity of the numerical formulations because the simulation results could not be matched without correct input data such as material properties and damping effects. In this paper, these values are obtained from real experiment with a high-speed camera and a data acquisition system. The simulation results with the absolute nodal coordinate formulation (ANCF) are compared with the results of real experiments. Two examples, a thin cantilever beam and a thin plate, are studied to verify whether the simulation results are well matched to experimental results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.213-219
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• 2001

This paper deals with the free vibration of two identical circular plates coupled with a bounded fluid. An analytical method based on the [mite Fourier-Bessel series expansion and Rayleigh-Ritz method is suggested. In the theory, it is assumed that the ideal fluid is filled in a rigid cylindrical container and the two plates are clamped along the plate edges. The proposed method is verified by the finite element analysis using commercial software with a good accuracy. Two transverse vibration modes, namely in-phase and out-of-phase, are observed alternately in the fluid-coupled system when the number of nodal circles increases for the fixed nodal diameter. The effect of gap between the plates on the fluid-coupled natural frequency is also investigated.

• Journal of Mechanical Science and Technology
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• 제18권5호
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• pp.742-752
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• 2004

Many papers have studied computer simulations of elastic bodies undergoing large deflections and large deformations. But there have not been many attempts to check the validity of the numerical formulations because the simulation results could not be matched without correct input data such as material properties and damping effects. In this paper, these values are obtained from real experiment with a high-speed camera and a data acquisition system. The simulation results with the absolute nodal coordinate formulation (ANCF) are compared with the results of real experiments. Two examples, a thin cantilevers beam and a thin plate, are studied to verify whether the simulation results are well matched to experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.530-532
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• 2001

This paper illustrates a method for evaluating nodal probabilistic production cost using the CMELDC. A new method for constructing CMELDC(the equivalent load duration curves of composite power system) was developed by authors. The CMELDC can be obtained by convolution integral processing between the probability distribution functions of the fictitious generators outage capacity and the load duration curves at each load point. Monte Carlo Methods are applied for the construction of CMELDC on this study. And IEEE-RTS 24 buses model is used as our case study with satisfactory results.

• Structural Engineering and Mechanics
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• 제41권6호
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• pp.735-750
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• 2012

This paper presents a comparison between two different procedures to deal with the geometric nonlinear analysis of space trusses, considering its structural stability aspects. The first nonlinear formulation, called positional, uses nodal positions rather than nodal displacements to describe the finite elements kinematics. The strains are computed directly from the proposed position concept, using a Cartesian coordinate system fixed in space. The second formulation, called corotational, is based on the explicit separation between rigid body motion and deformed motion. The numerical examples demonstrate the performances and the convergence of the responses for both analyzed formulations. Two numerical examples were compared, including a lattice beam with postcritical behavior. Despite the two completely different approaches to deal with the geometrical nonlinear problem, the results present good agreement.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.377-378
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• 2011

• 한국약용작물학회지
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• 제7권3호
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• pp.155-161
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• 1999

본 연구는 조직배양을 이용하여 도입된 다수확 우량마 (Dioscorea alata L. ) 의 대량증식을 위한 배양체계 를 확립 하였다. 식물생장조절제 (NAA) 및 sucrose를 첨가한 MS배지에서 마의 무균경단편을 배양하면 경단편에 괴경이 형성되었다. 이 괴경 형성에 미치는 식물생장조절제의 종류와 농도, Sucrose의 농도 및 광조건에 대한 영향을 조사한 결과, 마의 괴경 형성은 식물 생장조절제의 첨가에 의해 촉진되어서 괴경형성율은 NAA 1mg/l을 첨가한 배지에서 최고율이었다. Sucrose 농도를 높일수록 형성률이 상승되어 6%처리구에서 최고에 달했다. 괴경 형성에 가장 큰 영향을 미치는 것은 광조건으로 암흑조건의 형성율은 명조건 보다 크게 상회하였다. 그리고 암조건에서는 액아부위가 맹아하지 않고 무균 경단편에 괴경만이 형성 되었다. 이상의 결과에서 마의 괴경 형성에 최적의 배양조건은 NAA 1mg/l, surcrose 6%를 침 가한 1/2MS 배지에 무균경단편을 치상하여 $25^{\circ}C$ 암흑조건하에 배양한 것이었다.

• Journal of Gastric Cancer
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• 제5권3호
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• pp.163-168
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• 2005

목적: 본 연구에서는 제5판 UICC (International Union Against Cancer) 림프절 병기와 일본 위암 학회 림프절 병기를 분석하여 병기별 분포와 예후의 차이점을 알아보고자 하였다. 그리고 UICC N3M0 위암 환자들을 여러 림프절 전이군으로 분류하여 예후 예측에서 효용성을 알아보고자 하였다. 대상 및 방법: 1990년 2월부터 2000년 5월까지 지방공사 서울 의료원 및 한림대학교 성심병원에서 진행 위암으로 근치적 절제 수술을 받은 환자 197예를 대상으로 하여 두 가지 병기의 연관성 및 예후 예측의 차이를 분석하였다. 그리고 UICC N3M0군으로 분류된 58예를 세 가지의 림프절 병기 분류 방법으로 분석하였다. 결과: UICC 림프절 병기 N1, N2, N3의 5년 생존율은 각각 62.9%, 33.0%, 21.2%였다. 일본 위암 학회 림프절 병기 n1, n2의 5년 생존율은 각각 61.2%, 25.3%였다 N3M0군에서 일본 위암 학회 병기 n1의 5년 생존율이 각각 62.5%였고, 전이 림프절 비율 0.5 미만, 전이 림프절 수 26개 미만인 군에서는 각각 33.0%, 22.9%로 통계학적으로 의미 있게 0.5이상, 26개 이상의 군보다 좋은 예후를 보였다(P=0.018, 0.021). 결론: UICC 림프절 병기 체계는 예후 예측 능력에서 일본식 림프절 병기보다 더 우수했다. N3M0 병기 위암환자에서 전이 림프절 비율, 전이 림프절 수는 의미 있는 예후 인자였다.