• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.3
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• pp.19-28
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• 1990

The main purpose of this paper is to present both fundamental and some higher natural frequencies of catenary arcs. The differential equations governing planar free vibrations for these arcs are derived, in which the rotatory inertia is included, as non-dimensional forms and solved numerically to obtain frequencies and mode shapes. The hinged-hinged and clamped-clamped end constraints are applied in numerical examples. The lowest four natural frequencies are reported as the functions of non -dimensional system parameters; the slenderness ratio and the rise to span length ratio. The effects of rotatory inertia on natural frequencies are reported and some typical mode shapes are also presented.

• Proceedings of the Korean Society of Computational and Applied Mathematics Conference
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• 2003.09a
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• pp.16.2-16
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• 2003

미분 방정식의 수치적 해를 나타내는 방법 중 예측자-수정자 방법(predictor-corrector method)으로 알려진 Adams-Bashford-Moulton 방법은 다단계 방법을 이용하기 때문에 일단계 방법에 비하여 훨씬 좋은 수치적인 결과를 보여주고 있다. 이제, 이 다단계 방법에 오차제어 변수를 첨가한 새로운 형태의 예측자-수정자 방법을 제시하고 안정적인 해를 구할 수 있는 오차 제어 변수의 범위를 확인한다. 또한, 새로운 형태의 예측자-수정자 방법이 기존의 방법에 비하여 미분 방정식의 해에 대한 오차를 줄일 수 있는 방법임을 수치적인 결과를 통하여 검증한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.237-241
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• 2001

본 논문에서는 TSK (Takagi-Sugeno-Kang) 형태의 퍼지모델을 유도하는데 있어서, 동적시스템의 비선형 미분방정식을 선형화시 off-equilibrium에서 발생할 수 있는 상수항을 배제하고, TSK 퍼지 모델의 전건부 소속함수들을 GA(Genetic Algorithm)을 이용하여 최적화한후 이를 퍼지를 이용하여 합성함으로써, 실제 동적시스템을 묘사하는 비선형 미분방정식에 최적 근사화된 TSK 퍼지 모델링기법을 제시한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.2
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• pp.374-381
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• 1995

In this paper, integration methods for stiff constrained mechanical systems are studied to analyze dynamic response of the stiff mechanical system efficiently. The stiff, non-stiff systems are identified by using eigenvalues of the Jacobian of the systems. To integrate both stiff system and non-stiff system efficiently a new switching method between the non-stiff differential equation solver and the stiff differential equation solver is presented.

• Journal for History of Mathematics
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• v.31 no.5
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• pp.211-222
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• 2018

This paper surveys the theory of symmetry group of differential equations. A proof of the simplest version of the Noether's theorem on conservation laws has been presented with examples in the classical mechanics. As a new approach to the conservation laws the theory of characteristic cohomology due to S. H. Wang and others has been presented.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.8
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• pp.715-719
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• 2001

In this paper, we study the existence and uniqueness of fuzzy solution for the nonlinear fuzzy differential equations with nonlocal initial condition in E$^{2}$$_{N}$

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.8
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• pp.726-730
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• 2001

In this paper, we consider the observability conditions for the following nonlinear fuzzy neutral functional differential equations in E$^{2}$$_{N}$.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.17-19
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• 2002

In this paper, we study the controllability of fuzzy differential systems with nonlocal initial conditions. Result of this paper has improved and expanded in (5).

• Journal of KSNVE
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• v.7 no.6
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• pp.975-984
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• 1997

A direct boundary element method (DBEM) is developed for thin bodies whose surfaces are rigid or compliant. The Helmholtz integral equation and its normal derivative integral equation are adoped simultaneously to calculate the pressure on both sides of the thin body, instead of the jump values across it, to account for the different surface conditions of each side. Unlike the usual assumption, the normal velocity is assumed to be discontinuous across the thin body. In this approach, only the neutral surface of the thin body has to be discretized. The method is validated by comparison with analytic and/or numerical results for acoustic scattering and radiation from several surface conditions of the thin body; the surfaces are rigid when stationary or vibrating, and part of the interior surface is lined with a sound-absoring material.

• Journal of the Korea Computer Industry Society
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• v.7 no.1
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• pp.33-38
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• 2006

The motions of suspension bridge as well as hanging cable are governed by nonlinear partial differential equations. Nonlinearity gives rise to a large amplitude oscillation. We use finite difference methods to compute periodic solutions to the torsional partial differential equations. We use the one-noded forcing term and a slight perturbation in the forcing term.