• Title/Summary/Keyword: Dirichlet form

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Open Boundary Conditions in Parabolic Approximation Model (포물형 근사식 수치모형의 투과 경계조건)

  • Seo, Seung-Nam;Lee, Dong-Young
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.2
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    • pp.170-178
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    • 2007
  • Most of parabolic approximation models employ a relatively limited open boundary condition in which there is no depth variation in the longshore direction outside of the computation domain so that Snell's law may be presumed to hold. Existing Kirby's condition belongs to this category and in the paper both modified Kirby's method and Dirichlet boundary condition are presented in detail and numerical results of three methods were shown. Judging from computation to wave propagations over a circular shoal in a constant depth, the method based on present Dirichlet boundary condition with fictitious numerical adjusting regions in both sides of the computation domain gives the least distorted amplitude ratio distribution.

Prediction of Sound Field Inside Duct with Moving Medium by using one Dimensional Green's function (평균 유동을 고려한 1차원 그린 함수를 이용한 덕트 내부의 음장 예측 방법)

  • Jeon, Jong-Hoon;Kim, Yang-Hann
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.915-918
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    • 2005
  • Acoustic holography uses Kirchhoff·Helmholtz integral equation and Green's function which satisfies Dirichlet boundary condition Applications of acoustic holography have been taken to the sound field neglecting the effect of flow. The uniform flow, however, changes sound field and the governing equation, Green's function and so on. Thus the conventional method of acoustic holography should be changed. In this research, one possibility to apply acoustic holography to the sound field with uniform flow is introduced through checking for the plane wave in a duct. Change of Green's function due to uniform flow and one method to derive modified form of Kirchhoff·Heimholtz integral is suggested for 1-dimensional sound field. Derivation results show that using Green's function satisfying Dirichlet boundary condition, we can predict sound pressure in a duct using boundary value.

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CLASSIFICATION OF SINGULAR SOLUTIONS FOR THE POISSON PROBLEM WITH VARIOUS BOUNDARY CONDITIONS

  • Kim, Seok-Chan;Woo, Gyung-Soo;Kong, Soo-Ryoun
    • Honam Mathematical Journal
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    • v.31 no.4
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    • pp.579-590
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    • 2009
  • The precise form of singular functions, singular function representation and the extraction form for the stress intensity factor play an important role in the singular function methods to deal with the domain singularities for the Poisson problems with most common boundary conditions, e.q. Dirichlet or Mixed boundary condition [2, 4]. In this paper we give an elementary step to get the singular functions of the solution for Poisson problem with Neumann boundary condition or Robin boundary condition. We also give singular function representation and the extraction form for the stress intensity with a result showing the number of singular functions depending on the boundary conditions.

NUMERICAL RESULTS ON ALTERNATING DIRECTION SHOOTING METHOD FOR NONLINEAR PARTIAL DIFFERENTIAL EQUATIONS

  • Kim, Do-Hyun
    • The Pure and Applied Mathematics
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    • v.15 no.1
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    • pp.57-72
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    • 2008
  • This paper is concerned with the numerical solutions to steady state nonlinear elliptical partial differential equations (PDE) of the form $u_{xx}+u_{yy}+Du_{x}+Eu_{y}+Fu=G$, where D, E, F are functions of x, y, u, $u_{x}$, and $u_{y}$, and G is a function of x and y. Dirichlet boundary conditions in a rectangular region are considered. We propose alternating direction shooting method for solving such nonlinear PDE. Numerical results show that the alternating direction shooting method performed better than the commonly used linearized iterative method.

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THE SPECTRAL GEOMETRY OF EINSTEIN MANIFOLDS WITH BOUNDARY

  • Park, Jeong-Hyeong
    • Journal of the Korean Mathematical Society
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    • v.41 no.5
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    • pp.875-882
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    • 2004
  • Let (M,g) be a compact m dimensional Einstein manifold with smooth boundary. Let $\Delta$$_{p}$,B be the realization of the p form valued Laplacian with a suitable boundary condition B. Let Spec($\Delta$$_{p}$,B) be the spectrum where each eigenvalue is repeated according to multiplicity. We show that certain geometric properties of the boundary may be spectrally characterized in terms of this data where we fix the Einstein constant.ant.

A Closed-Form Bayesian Inferences for Multinomial Randomized Response Model

  • Heo, Tae-Young;Kim, Jong-Min
    • Communications for Statistical Applications and Methods
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    • v.14 no.1
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    • pp.121-131
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    • 2007
  • In this paper, we examine the problem of estimating the sensitive characteristics and behaviors in a multinomial randomized response model using Bayesian approach. We derived a posterior distribution for parameter of interest for multinomial randomized response model. Based on the posterior distribution, we also calculated a credible intervals and mean squared error (MSE). We finally compare the maximum likelihood estimator and the Bayes estimator in terms of MSE.

PENALIZED NAVIER-STOKES EQUATIONS WITH INHOMOGENEOUS BOUNDARY CONDITIONS

  • Kim, Hongchul
    • Korean Journal of Mathematics
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    • v.4 no.2
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    • pp.179-193
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    • 1996
  • This paper is concerned with the penalized stationary incompressible Navier-Stokes system with the inhomogeneous Dirichlet boundary condition on the part of the boundary. By taking a generalized velocity space on which the homogeneous essential boundary condition is imposed and corresponding trace space on the boundary, we pose the system to the weak form which the stress force is involved. We show the existence and convergence of the penalized system in the regular branch by extending the div-stability condition.

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TWO JUMPING NONLINEAR TERMS AND A NONLINEAR WAVE EQUATION

  • Jung, Tacksun;Choi, Q-Heung
    • Journal of the Chungcheong Mathematical Society
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    • v.22 no.4
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    • pp.675-687
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    • 2009
  • We find the multiple nontrivial solutions of the equation of the form $u_{tt}-u_{xx}=b_1[(u+1)^{+}-1]+b_2[(u+2)^{+}-2]$ with Dirichlet boundary condition. Here we reduce this problem into a two-dimensional problem by using variational reduction method and apply the Mountain Pass theorem to find the nontrivial solutions.

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GLOBAL BIFURCATION FOR GENERALIZED LAPLACIAN OPERATORS

  • Kim, In-Sook
    • Journal of the Korean Mathematical Society
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    • v.46 no.1
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    • pp.31-39
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    • 2009
  • A bifurcation problem for nonlinear partial differential equations of the form $$div({\varphi}(|{\nabla}u|){\nabla}u+{\mu}_0{\varphi}(|u|)u=q({\lambda},\;x,\;u,\;{\nabla}u)$$ subject to Dirichlet boundary conditions is discussed. Using a global bifurcation theorem of Rabinowitz type, we show that under certain conditions on $\varphi$ and q, the above equation has an unbounded connected set of solutions (u, $\lambda$).

EXISTENCE OF SOLUTIONS FOR GRADIENT TYPE ELLIPTIC SYSTEMS WITH LINKING METHODS

  • Jin, Yinghua;Choi, Q-Heung
    • Journal of the Chungcheong Mathematical Society
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    • v.20 no.1
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    • pp.65-70
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    • 2007
  • We study the existence of nontrivial solutions of the Gradient type Dirichlet boundary value problem for elliptic systems of the form $-{\Delta}U(x)={\nabla}F(x,U(x)),x{\in}{\Omega}$, where ${\Omega}{\subset}R^N(N{\geq}1)$ is a bounded regular domain and U = (u, v) : ${\Omega}{\rightarrow}R^2$. To study the system we use the liking theorem on product space.

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