• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 춘계학술대회 학술발표 논문집
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• pp.69-72
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• 2001

In this paper, we propose a new design method for bidirectional associative memories model with high error correction ratio. We extend the conventional GBAM model using bias terms and formulate a design procedure in the form of a constrained optimization problem. The constrained optimization problem is then transformed into a GEVP(generalized eigenvalue problem), which can be efficiently solved by recently developed interior point methods. The effectiveness of the proposed approach is illustrated by a example.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2005년도 춘계학술대회 학술발표 논문집 제15권 제1호
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• pp.185-188
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• 2005

This paper suggests a control method for efficient topology/parameter evolution in a bond-graph-based GP design framework that automatically synthesizes designs for multi-domain, lumped parameter dynamic systems, We adopt a hierarchical breeding control mechanism with fitness-level-dependent differences to obtain better balancing of topology/parameter search - biased toward topological changes at low fitness levels, and toward parameter changes at high fitness levels. As a testbed for this approach, an eigenvalue assignment problem, which is to find bond graph models exhibiting minimal distance errors from target sets of eigenvalues, was tested and showed improved performance for various sets of eigenvalues.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.355-360
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• 2000

This paper presents properties of piecewise cubic B-spline function and Rayleigh-Ritz method to compute the smallest eigenvales. In order to compute the smallest eigenvalues, Rayleigh quotient approach is used and four different types of finite element approximating functions corresponding to the statical deflection curve, spanned by the linearly independent set of piecewise cubic B-spline functions with equally spaced 5 knots from a partion of [0, 1], each satisfying homogeneous boundary conditions with constraining effects are used to compute the smallest eigenvalues for a Sturm-Lionville boundary equations of u"＋ λ²u＝0, u(0.0)＝u(0.0)＝0, 0≤x≤1.0.

• 대한수학회논문집
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• 제16권3호
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• pp.437-443
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• 2001

In this paper the inverse problems for the Dirac Operator are studied. A set of values of eigenfunctions in some internal point and spectrum are taken as a data. Uniqueness theorems are obtained. The approach that was used in the investigation of inverse problems for interior spectral data of the Sturm-Liouville operator is employed.

• 한국전자통신학회논문지
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• 제7권5호
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• pp.1033-1039
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• 2012

본 논문에서는 여러 장의 후판이 포함된 영상에서 고유값을 이용하여 직선 패턴을 검출하고 이를 바탕으로 각각의 후판을 인식하는 간단하면서도 정확한 알고리즘을 제안한다. 후판 영상으로부터 후판에 관련된 정보를 분석 및 인식하기 위해서 먼저 후판의 직선 에지를 검출한다. 후판 영상의 직선 에지 검출을 위해 제안하는 알고리즘에서는 마스크를 이용하여 전체 영상을 탐색하면서 에지 영상을 분석한다. 먼저 마스크에 위치한 에지 패턴의 픽셀들에 대한 공분산 행렬을 계산하고 공분산 행렬의 고유값과 에지 패턴의 통계적 특성과 기하학적인 특성 사이의 관계를 분석하여 직선 에지를 검출한다. 다음으로 직선 에지의 방향 정보와 원점에서의 거리 정보를 분석하여 전체 영상에서 각각의 후판을 검출한다. 다양한 후판 영상에 대해서 실험을 수행한 결과는 제안하는 알고리즘이 전체 영상에서 각각의 후판을 효과적으로 검출함을 보여준다.

• Structural Engineering and Mechanics
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• 제9권5호
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• pp.449-467
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• 2000

The natural frequencies and the corresponding mode shapes of a non-uniform beam carrying multiple point masses are determined by using the analytical-and-numerical-combined method. To confirm the reliability of the last approach, all the presented results are compared with those obtained from the existing literature or the conventional finite element method and close agreement is achieved. For a "uniform" beam, the natural frequencies and mode shapes of the "clamped-hinged" beam are exactly equal to those of the "hinged-clamped" beam so that one eigenvalue equation is available for two boundary conditions, but this is not true for a "non-uniform" beam. To improve this drawback, a simple transformation function ${\varphi}({\xi})=(e+{\xi}{\alpha})^2$ is presented. Where ${\xi}=x/L$ is the ratio of the axial coordinate x to the beam length L, ${\alpha}$ is a taper constant for the non-uniform beam, e=1.0 for "positive" taper and e=1.0+$|{\alpha}|$ for "negative" taper (where $|{\alpha}|$ is the absolute value of ${\alpha}$). Based on the last function, the eigenvalue equation for a non-uniform beam with "positive" taper (with increasingly varying stiffness) is also available for that with "negative" taper (with decreasingly varying stiffness) so that half of the effort may be saved. For the purpose of comparison, the eigenvalue equations for a positively-tapered beam with five types of boundary conditions are derived. Besides, a general expression for the "normal" mode shapes of the non-uniform beam is also presented.

• 한국공간구조학회논문집
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• 제10권2호
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• pp.87-94
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• 2010

본 논문은 고유치문제로 정식화된 텐세그러티 구조물의 형상탐색에 대하여 제시하고자 한다. 텐세그러티 구조물의 안정을 위해서는 형상탐색을 수행하여야한다. 형상탐색을 위한 해석 방법은 내력밀도법과 일반역행렬을 이용한 방법, 이 두 가지가 널리 알려져 있다. 본 연구는 새롭게 형상을 탐색하는 방법을 제시하여 텐세그러티 구조물의 자기평형 응력을 얻었다. 제시한 방법은 기존의 방법을 기본으로 한 모든 절점의 평형 방정식을 고유치 문제로 정식화하였다. 이를 증명하기 위해 몇 가지 예제(텐세그러티 구조물)를 기존의 방법과 비교 하였다. 본 연구에서 제시된 방법은 기존의 방법과 같은 결과가 나왔으며, 나아가 해답을 얻는 과정이 훨씬 간단하였다.

• Structural Engineering and Mechanics
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• 제40권5호
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• pp.637-654
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• 2011

The present paper studies the variation of the natural frequencies and mode shapes of rectangular plates carrying a three degree-of-freedom spring-mass system (subsystem), when the subsystem changes (stiffness, mass, moment of inertia, location). An analytical approach based on Lagrange multipliers as well as a finite element formulation are employed and compared. Numerically reliable results are presented for the first time, illustrating the convenience of using the present analytical method which requires only the solution of a linear eigenvalue problem. Results obtained through the variation of the mass, stiffness and moment of inertia of the 3-DOF system can be understood under the effective mass concept or Rayleigh's statement. The analysis of frequency values of the whole system, when the 3-DOF system approaches or moves away from the center, shows that the variations depend on each particular mode of vibration. When the 3-DOF system is placed in the center of the plate, "new" modes are found to be a combination of the subsystem's modes (two rotations, traslation) and the bare plate's modes that possess the same symmetry. This situation no longer exists as the 3-DOF system moves away from the center of the plate, since different bare plate's modes enable distinct motions of the 3-DOF system contributing differently to the "new' modes as its location is modified. Also the natural frequencies of the compound system are nearly uncoupled have been calculated by means of a first order eigenvalue perturbation analysis.

• 한국지진공학회논문집
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• 제2권1호
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• pp.79-93
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• 1998

철근콘크리트부재가 갖는 균열의 발생, 항복 및 파괴 등의 단계별 역학적 거동의 특성을 정확히 예측하고 모사할 수 있는 해석기법의 개발을 목적으로 하였다. 이를 위해서 균열발생후의 철근과 콘크리트의 부착거동, 균열면에서의 골재의 맞물림 거동 및 철근항복후의 모델링 등에 의해서 반복하중을 받는 철근콘크리트 구조부재의 항복후 파괴거동을 예측할 수 있는 해석모델을 개발하였다. 두께가 서로 다릉 부재간의 접합부에서는 단면강성이 급변하기 때문에 기초의 바닥으로부터 철근의 인발, 접합면의 미끄러짐 및 접합면의 관입 등의 국소적인 불연속 변형이 집중하게 된다. 이와 같은 국소적인 불연속 교각구조의 변형능력에 미치는 기여도는 일반적으로 무시할 수 없는 정도이므로, 불연속 변형을 고려하기 위한 접합요소(joint element)를 도입하였다. 또한 축방향철근 및 횡방향 구속철근의 유무 및 그 양 등에 따른 구속효과를 적절히 표현할 수 있는 해석모델을 개발하였다. 각각의 해석모델들을 조합한 유한요소 해석프로그램에 의한 결과를 다른 연구자들의 결과와 비교하여 타당성을 검증하였다.

• 한국강구조학회 논문집
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• 제8권3호통권28호
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• pp.21-34
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• 1996

A numerical method is presented for computation of eigenvector derivatives used an iterative procedure with guaranteed convergence. An approach for treating the singularity in calculating the eigenvector derivatives is presented, in which a shift in each eigenvalue is introduced to avoid the singularity. If the shift is selected properly, the proposed method can give very satisfactory results after only one iteration. A criterion for choosing an adequate shift, dependent on computer hardware is suggested ; it is directly dependent on the eigenvalue magnitudes and the number of bits per numeral of the computer. Another merit of this method is that eigenvector derivatives with repeated eigenvalues can be easily obtained if the new eigenvectors are calculated. These new eigenvectors lie "adjacent" to the m (number of repeated eigenvalues) distinct eigenvectors, which appear when the design parameter varies. As an example to demonstrate the efficiency of the proposed method in the case of distinct eigenvalues, a cantilever plate is considered. The results are compared with those of Nelson's method which can find the exact eigenvector derivatives. For the case of repeated eigenvalues, a cantilever beam is considered. The results are compared with those of Dailey's method which also can find the exact eigenvector derivatives. The design parameter of the cantilever plate is its thickness, and that of the cantilever beam its height.