• Structural Engineering and Mechanics
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• 제45권2호
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• pp.169-182
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• 2013

The mechanical behavior of rectangular foundation plates with perimetric beams and internal stiffening beams of the plate is herein analyzed, taking the foundation design into account. A series of dimensionless parameters related to the geometry of the studied elements were defined. In order to generalize the problem statement, an initial settlements was considered. A numeric procedure was developed for the resolution by means of the Finite Differences Method that takes into account the stiffness of the plate, the perimetric and internal plate beams and the soil reaction module. Iterative algorithms were employed which, for each of the analyzed cases, made it possible to find displacements and reaction percentages taken by the plate and those that discharge directly into the perimetric beams, practically without affecting the plate. To enhance its mechanical behavior the internal stiffening beams were prestressed and the results obtained with and without prestressing were compared. This analysis was made considering the load conditions and the soil reaction module constant.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.480-483
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• 2005

A roll forming process is developed for an automotive part of high strength steel. Forming rolls are designed through the plane strain elastic-plastic finite element analysis to estimate the springback. It is assumed that the process can be approximated as a series of multi-step bending processes. Then the 3D elastic-plastic finite element analysis with the solid element is carried out for the designed roll forming process. The prototype roll forming machine and the forming rolls are made and the experiments are carried out. The results of the analysis and the experiments are compared.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
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• pp.113-116
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• 2001

이 논문에서는 음악을 시계열 자료로 해석하고 시계열 자료의 퍼지 로직에 기반한 모델링에 대해 설명한다. 음악은 음악적 기호들인 보표, 악센트, 오선, 박자표, 음표, 쉼표 등등과 같은 유한개의 음악적 표기법들로 구성된다. 악보는 음악 해석에 필요한 리듬, 멜로디, 화음등과 달은 다양한 특성을 표현하기 위해 음악적 기호들을 사용한다. 본 논문에서는 각각의 시간에서 소리나는 음들의 비트와 높낮이로 인식한다는 관점에서 음악에서의 비트와 음의 높낮이를 시계열 자료로 표현하는 것이 가능하다. 악보의 규정된 특징들을 바탕으로, 악보를 시계열 자료로 표현하고 시계열을 예측하기 위해 퍼지 로직에 기반한 모델로 구성한다. 제안한 방법의 타당성으로 보이기 위해 몇 가지 예를 제시한다.

• Journal of Advanced Research in Ocean Engineering
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• 제1권3호
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• pp.157-167
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• 2015

In order to provide simple and accurate wave theory in design of offshore structure, an analytical approximation is introduced in this paper. The solution is limited to flat bottom having a constant water depth. Water is considered as inviscid, incompressible and irrotational. The solution satisfies the continuity equation, bottom boundary condition and non-linear kinematic free surface boundary condition exactly. Error for dynamic condition is quite small. The solution is suitable in description of breaking waves. The solution is presented with closed form and dispersion relation is also presented with closed form. In the last century, there have been two main approaches to the nonlinear problems. One of these is perturbation method. Stokes wave and Cnoidal wave are based on the method. The other is numerical method. Dean's stream function theory is based on the method. In this paper, power series method was considered. The power series method can be applied to certain nonlinear differential equations (initial value problems). The series coefficients are specified by a nonlinear recurrence inherited from the differential equation. Because the non-linear wave problem is a boundary value problem, the power series method cannot be applied to the problem in general. But finite number of coefficients is necessary to describe the wave profile, truncated power series is enough. Therefore the power series method can be applied to the problem. In this case, the series coefficients are specified by a set of equations instead of recurrence. By using the set of equations, the nonlinear wave problem has been solved in this paper.

• 대한수학회논문집
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• 제26권4호
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• pp.603-610
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• 2011

In this paper, we propose an algorithm for identifying ${\omega}_j{\in}(0,\;{\infty}),\;a_j,b_j{\in}\mathbb{C}$ and N of the following trigonometric series $f(t)=a_0+ \sum\limits_{j=1}^N[a_jcos{\omega}_jt+b_j\;sin{\omega}_jt]$ by means of the finite number of sample values. We prove that the frequency components are shown to be the solutions of some characteristic equation related to the inverse of a Hankel matrix derived from the sample values.

• 한국음향학회지
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• 제18권7호
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• pp.39-44
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• 1999

직사각형 평판의 고유진동수와 진동모드를 연구하였다. 이중 퓨리에 사인시리즈를 직사각형 평판의 모달 변위함수로 사용하였으며, 다양한 경계조건을 가지는 자유진동 해석에 적용하였다. 유한급수 전개로써 근사해를 나타내는 고전적인 Ritz 방법을 이용해서 직사각형 평판의 고유진동수를 해석한 Leissa의 결과와 본 연구의 결과를 비교하였다. 그리고, 평판의 형상비에 따른 영향도 연구하였다. 자유경계 평판, 외팔평판, 고정평판, 그리고 모서리가 단순지지된 직사각형 평판의 진동형태를 가시화 하였다.

• Journal of Mechanical Science and Technology
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• 제18권8호
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• pp.1297-1305
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• 2004

In this paper, we propose a new scheme for the discretization of nonlinear systems using Taylor series expansion and the zero-order hold assumption. This scheme is applied to the sampled-data representation of a non-affine nonlinear system with constant input time-delay. The mathematical expressions of the discretization scheme are presented and the ability of the algorithm is tested for some of the examples. The proposed scheme provides a finite-dimensional representation for nonlinear systems with time-delay enabling existing controller design techniques to be applied to them. For all the case studies, various sampling rates and time-delay values are considered.

• Kyungpook Mathematical Journal
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• 제48권3호
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• pp.443-455
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• 2008

For an extension $A\;{\subseteq}\;B$ of commutative rings, we present a sufficient conditio for the ring $[[A^{S,\;\leq}]]$ of generalized power series to be weakly normal (resp., stronglyt-closed) in $[[B^{S,\;\leq}]]$, where (S, $\leq$) be a torsion-free cancellative strictly ordered monoid. As a corollary, it can be applied to the ring of power series in infinitely many indeterminates as well as in finite indeterminates.

• Structural Engineering and Mechanics
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• 제8권4호
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• pp.343-360
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• 1999

This work applies a structural analysis method based on an analytical solution from the Fourier series which transforms a half-range cosine expansion into a static solution involving plated structures. Two sub-matrices of in-plane and plate-bending problems are also formulated and coupled with the prescribed boundary conditions for these variables, thereby providing a convenient basis for a numerical solution. In addition, the plate connection are introduced by describing the connection between common boundary continuity and equilibrium. Moreover, a simple computation scheme is proposed. Numerical results are then compared with finite element results, demonstrating the numerical scheme's versatility and accuracy.

• 대한수학회보
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• 제50권4호
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• pp.1389-1413
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• 2013

In this paper, we consider several convolution sums, namely, $\mathcal{A}_i(m,n;N)$ ($i=1,2,3,4$), $\mathcal{B}_j(m,n;N)$ ($j=1,2,3$), and $\mathcal{C}_k(m,n;N)$ ($k=1,2,3,{\cdots},12$), and establish certain identities involving their finite products. Then we extend these types of product convolution identities to products involving Faulhaber sums. As an application, an identity involving the Weierstrass ${\wp}$-function, its derivative and certain linear combination of Eisenstein series is established.