• 한국항행학회논문지
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• 제18권1호
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• pp.78-83
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• 2014

본 논문에서는 2개 유전체층 위의 완전도체띠 격자구조에 의한 TM (transverse magnetic)산란의 급속한 수렴 해에 대한 문제를 수치해석 방법인 FGMM (Fourier Galerkin moment method)를 이용하여 해석하였다. TM 산란에 대하여 유도되는 표면 전류밀도는 스트립 양 끝에서 매우 큰 값이 예측되므로, 이때 스트립에 유도되는 전류밀도는 적절한 모서리 경계조건을 만족하는 함수와 1종 Chebyshev 다항식의 곱의 급수로 전개하였다. 도체띠에 유도되는 전류밀도, 정규화된 반사전력 및 투과전력을 계산하였다. 제안된 함수를 사용한 수치결과는 기존의 지수함수를 사용했을 때 보다 빠르게 수렴도가 향상되었으며, 수치결과들은 기존 논문들의 결과들과 비교하여 거의 일치하였다.

• 농업과학연구
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• 제39권4호
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• pp.535-543
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• 2012

Botanic gardens are steadily increasing based on people's increased interests in environment and ecology, lengthened leisure hours and improved transportation. However, similar florae and undifferentiated display are considered as problems, while their functions, purposes and characteristics have been more diversified. This study aims to investigate the present conditions and problems of display at botanic gardens and to find out solutions to make them exhibit plants through various ways of display and have their own characteristic, through a case study of seven botanic gardens. As botanic gardens are being recognized as a cultural institution, they should have limitations in the aspect of places that simply collect and exhibit rare plants. The current problems are unclear setting of design goals and communication with visitors. The gardens should escape from the existing supplier-oriented view to a visitor-oriented view, thinking about what the visitors will be able to see and get there. In particular, their display lacks differency, aesthetics, eye-level display, and multi-layered display. In addition to the essential functions of collecting the world's plants, exhibiting them according to purposes and giving scientific learning, botanic gardens should also show a sense of seasons with plants, trigger interests and amusement through unique plants, make visitors more interested in florae and closer to plants, and include social functions. Botanic gardens should be capable of leaning resources display, speciated display, complex and convergent garden-type display, and display fit for local and cultural contexts.

• 한국전자파학회지:전자파기술
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• 제6권1호
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• pp.10-16
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• 1995

완전도체 스트립 회절격자에 의한 E-분극 산문제를 모멘트법을 이용하여 해석하였다. E분극의 경우는 청도 되는 표면전류밀도가 모서리 양 끝에서 매우 높을 것으로 추측된다. 이때 스트립에 청도되는 표면전류밀도는 차수가 0인 Ultraspherical 다항식의 급수와 적절한 모서리 경계조건을 만족하는 함수의 곱의 급수로 전개하였다. 전류밀도와 반사계수에 대한수직결과를 기존의 다른 수틀과 비교하였다. 본 논문의 수치결과가 기존의 다른 수를 사용했을 때 보다 기하학적 반사계수의 경도가 매우 빠르게 향상됨을 보였다. 기하학적 반사계수에서의 급변점 위치는 입사각, 스트립 폭 및 스트립 주기를 변화시킴으로써 이동시킬 수 있었다.

• 한국컴퓨터정보학회논문지
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• 제11권3호
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• pp.107-115
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• 2006

본 논문에서는 캐스케이드 코릴레이션 학습 알고리즘을 위한 새로운 클래스의 활성화 함수를 소개한다. 이 함수는 코사인으로 모듈화된 가우스 함수로서 편의상 이 활성화 함수를 코스가우스(CosGauss) 함수라고 칭하기로 한다. 이 함수는 기존의 시그모이드 함수(sigmoidal function), 하이퍼볼릭탄젠트 함수(hyperbolic tangent function), 가우스 함수(gaussian function)에 비해서 등성이(ridge)를 더 많이 얻을 수 있다. 이러한 등성이들로 인하여 빠른 속도로 수렴하고 패턴인식 속도를 향상 시켜서 학습 능력을 향상시킬 수 있다. 캐스케이드 코릴레이션 네트워크에 이 활성화 함수를 사용하여 중요한 기준 문제(benchmark problem)의 하나인 이중나선 문제(two spirals problem)에 대하여 실험하여 다른 활성화 함수들과 결과 값을 비교하였다.

• 대한토목학회논문집
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• 제32권1A호
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• pp.11-18
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• 2012

이 논문에서는 유리-에폭시 섬유 보강 복합재료판에 $K_I$ 과 $K_{II}$ 에 의한 혼합모우드 상태의 균열된 알루미늄판의 응력확대계수의 수치해석 산정을 다루고 있다. 응력확대계수 산정을 위한 가상균열닫힘법과 2단계 확장법이 고려된다. 에너지 방출률과 응력확대계수의 항으로 표현되는 파괴역학 매개변수 계산을 위하여, p-수렴 부분 층별모델이 채택된다. 고려되는 p-수렴 방식은 저매개변수 요소의 개념에 기초한다. 1개 층에 대해 가정된 변위장, 변위-변형률 관계, 그리고 3차원 구성방정식은 2차원과 1차원 고차 형상함수의 조합으로 정의된다. 고려되는 요소는 변위장의 보간과 수치적분을 수행하기 위해 로바토 형상함수와 가우스-로바토 적분법이 사용된다. 언급된 모델과 기법들을 사용하여, 경사각도의 변화에 따른 적층판 형상의 효과와 접착제의 강도가 팻치보강 시스템에 미치는 영향이 조사된다. 중립축 변화에 따른 팻치보강 적층판의 면외 휨 효과도 분석된다. 고려되는 모델의 정확성과 단순성 등에 관해서 응력확대계수, 응력분포, 자유도 수, 에너지 방출률 등의 항목을 가지고서 평가된다.

• 대한인간공학회지
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• 제26권3호
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• pp.67-80
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• 2007

Digital convergence, defined as the creative fusion of once-independent technologies and service, is getting more attention recently. Interruptions among internal functions happen frequently in digital convergence products because many functions that were in separate products are merged into a single product. Multi-tasking and multi-modality are two distinctive features of interruption in digital convergence products, but their impacts to the user have not been investigated yet. This study conducted a controlled experiment to investigate the impacts of multi-tasking and multi-modality on the subjective satisfaction and objective performance of digital convergent products. The study results indicate that multi-tasking and multi-modality have substantial effects individually as well as together. The paper ends with practical and theoretical implications of study results as well as research limits and future research.

• Structural Engineering and Mechanics
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• 제22권3호
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• pp.331-349
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• 2006

The stresses and deflections in a laminated rectangular plate under thermal vibration are determined by using the moving least squares differential quadrature (MLSDQ) method based on the first order shear deformation theory. The weighting coefficients used in MLSDQ approximation are obtained through a fast computation of the MLS shape functions and their partial derivatives. By using this method, the governing differential equations are transformed into sets of linear homogeneous algebraic equations in terms of the displacement components at each discrete point. Boundary conditions are implemented through discrete grid points by constraining displacements, bending moments and rotations of the plate. Solving this set of algebraic equations yields the displacement components. Then substituting these displacements into the constitutive equation, we obtain the stresses. The approximate solutions for stress and deflection of laminated plate with cross layer under thermal load are obtained. Numerical results show that the MLSDQ method provides rapidly convergent and accurate solutions for calculating the stresses and deflections in a multi-layered plate of cross ply laminate subjected to thermal vibration of sinusoidal temperature including shear deformation with a few grid points.

• 전기학회논문지
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• 제57권1호
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• pp.20-24
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• 2008

A bid-based pool(BBP) model is representative of energy market structure in a number of restructured electricity markets. Supply function equilibrium(SFE) models of interaction better match what is explicitly required in the bid formats of typical BBP markets. Many of the results in the SFE literature involve restrictive parametrization of the bid cost functions. In the SFE models, two parameters, intercept and slope, are available for strategic bidding. This paper addresses the realistic competition format that players can choose both parameters arbitrarily. In a fixed demand function, equilibrium conditions for generation company's profit maximization have a degree of freedom, which induces multi-equilibrium. So it is hard to choose a convergent equilibrium. However, consideration of stochastic demand function makes the equilibrium conditions independent each other based on the amount of variance of stochastic demand function. This variance provides the bidding players with incentives to change the slope parameter from an equilibrium for a fixed demand function until the slope parameter equilibrium.

• Smart Structures and Systems
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• 제13권1호
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• pp.111-135
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• 2014

Based on the Reissner mixed variational theorem (RMVT), finite rectangular layer methods (FRLMs) are developed for the three-dimensional (3D) linear buckling analysis of simply-supported, fiber-reinforced composite material (FRCM) and functionally graded material (FGM) sandwich plates subjected to bi-axial compressive loads. In this work, the material properties of the FGM layers are assumed to obey the power-law distributions of the volume fractions of the constituents through the thickness, and the plate is divided into a number of finite rectangular layers, in which the trigonometric functions and Lagrange polynomials are used to interpolate the in- and out-of-plane variations of the field variables of each individual layer, respectively, and an h-refinement process is adopted to yield the convergent solutions. The accuracy and convergence of the RMVT-based FRLMs with various orders used for expansions of each field variables through the thickness are assessed by comparing their solutions with the exact 3D and accurate two-dimensional ones available in the literature.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1086-1091
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• 2005

This paper focuses on intelligent control of induction motor by hybrid system consisting of GA-PSO. Induction motor has been using in industrial area. However, it is challengeable on how we control effectively. From this point, an optimal solution using GA (Genetic Algorithm) and PSO (Particle Swarm Optimization) is introduced to intelligent control. In this case, it is possible to obtain local solution because chromosomes or individuals which have only a close affinity can convergent. To improve an optimal learning solution of control, This paper deal with applying PSO and Euclidian data distance to mutation procedure on GA's differentiation. Through this approaches, we can have global and local optimal solution together, and the faster and the exact optimal solution without any local solution. Four test functions are used for proof of this suggested algorithm.