• Title/Summary/Keyword: The Form of Boundary

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A Numerical Simulation of Horizontal Convection in Mesoscale (중규모에서의 수평대류에 관한 수치모의)

  • 정우식;이화운
    • Journal of Environmental Science International
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    • v.7 no.2
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    • pp.233-241
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    • 1998
  • This study Is concerned with properties of a thermal convection in a stably stratified Boussinesq fluid caused by partial heating at the lower boundary. For thins purpose, two-dimensional, nonrotating system was employed. U the heating is very strong, convection takes the form of a turbulent plume. Othenuse, remains laminar. If the partial heating at the bottom boundary Is symmetric. the convection takes the form of a trubuient plume. Otherwise remains but beating form Is not so signiacant as to alter the vergence in the lower layer at the center of the partial heating area. The temperature perturbation is characterized by the temperature 'Cross-Over' over the partial heating area. These features are cleared ac- cording to the Increase of temperature difference between the center and side part of the bottom boundary.

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Radial basis collocation method for dynamic analysis of axially moving beams

  • Wang, Lihua;Chen, Jiun-Shyan;Hu, Hsin-Yun
    • Interaction and multiscale mechanics
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    • v.2 no.4
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    • pp.333-352
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    • 2009
  • We introduce a radial basis collocation method to solve axially moving beam problems which involve $2^{nd}$ order differentiation in time and $4^{th}$ order differentiation in space. The discrete equation is constructed based on the strong form of the governing equation. The employment of multiquadrics radial basis function allows approximation of higher order derivatives in the strong form. Unlike the other approximation functions used in the meshfree methods, such as the moving least-squares approximation, $4^{th}$ order derivative of multiquadrics radial basis function is straightforward. We also show that the standard weighted boundary collocation approach for imposition of boundary conditions in static problems yields significant errors in the transient problems. This inaccuracy in dynamic problems can be corrected by a statically condensed semi-discrete equation resulting from an exact imposition of boundary conditions. The effectiveness of this approach is examined in the numerical examples.

NOTE ON LOCAL ESTIMATES FOR WEAK SOLUTION OF BOUNDARY VALUE PROBLEM FOR SECOND ORDER PARABOLIC EQUATION

  • Choi, Jongkeun
    • Bulletin of the Korean Mathematical Society
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    • v.53 no.4
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    • pp.1123-1148
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    • 2016
  • The aim of this note is to provide detailed proofs for local estimates near the boundary for weak solutions of second order parabolic equations in divergence form with time-dependent measurable coefficients subject to Neumann boundary condition. The corresponding parabolic equations with Dirichlet boundary condition are also considered.

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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GEOMETRIC CHARACTERIZATION OF q-PSEUDOCONVEX DOMAINS IN ℂn

  • Khedhiri, Hedi
    • Bulletin of the Korean Mathematical Society
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    • v.54 no.2
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    • pp.543-557
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    • 2017
  • In this paper, we investigate the notion of q-pseudoconvexity to discuss and describe some geometric characterizations of q-pseudoconvex domains ${\Omega}{\subset}{\mathbb{C}}^n$. In particular, we establish that ${\Omega}$ is q-pseudoconvex, if and only if, for every boundary point, the Levi form of the boundary is semipositive on the intersection of the holomorphic tangent space to the boundary with any (n-q+1)-dimensional subspace $E{\subset}{\mathbb{C}}^n$. Furthermore, we prove that the Kiselman's minimum principal holds true for all q-pseudoconvex domains in ${\mathbb{C}}^p{\times}{\mathbb{C}}^n$ such that each slice is a convex tube in ${\mathbb{C}}^n$.

A Finite Element Solution to the Group Diffusion Problems with Albedo-Type Boundary Conditions (Albedo형 경계조건을 가진 다군확산문제에 대한 유한요소해)

  • Kun Joong Yoo;Chang Hyo Kim;Chang Hyun Chung
    • Nuclear Engineering and Technology
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    • v.14 no.4
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    • pp.178-185
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    • 1982
  • Albedo-type boundary condition is incorporated into the finite element formulation of the cubic Hermite polynomials for the two-dimensional solution of the two-group diffusion problem. Two modifications are introduced with respect to the conventional expression for the weak form of the group diffusion equation with the zero flux or zero current boundary condition and the cubic element functions over the boundary nodes. The finite element formulations obtained from those modifications are tested with the two-dimensional ZION problem. The numerical effectiveness of the modifications are examined.

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A Study on the Application of Boundary and Territory in Aspects of the Spatial Organization of Architecture (건축공간구성에 있어서 경계와 영역의 활용에 관한 연구)

  • Kwon, Se-Hoon
    • Journal of The Korean Digital Architecture Interior Association
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    • v.4 no.1
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    • pp.10-16
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    • 2004
  • Territory is determined by physical elements that provide the occupants an obvious boundary in a space. The creation of boundary is a interpersonal process by which a person or group regulates interactions with others. The perception of territory needs boundary regulations that mean the composition of horizontal and vertical elements in architectural space. The perception of territory can be defined as perceptual reaction considering not only visual perception on the physical elements in the architectural space and also various kinds of social activity in architectural environment. To achiever territory in architectural space, visible and invisible boundary regulation should be need. It means that territorial boundary regulation needs visual and audial boundary regulation as well as spatial boundary regulation.

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A new absorbing boundary condition for the FDTD simulation of waveguides (도파관 구조의 FDTD해석을 위한 새로운 흡수경계조건)

  • 박면주;남상욱
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.12
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    • pp.3227-3234
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    • 1996
  • This paper proposes a new absorbing boundary condition(ABC) for the FDTD simulation of waveguide problems. It is based on the exact analytic expression for the time domain EM wave propatation in the waveguide. The ABC derived from the expression has a convolution form whose kernel (the discrete Green's function) has a simple, closed form formula. Also, it is applicable to the wide variety of waveguide types with conducting boundaries and complex cross-sectional shapes.

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SOLUTION OF THE BOUNDARY LAYER EQUATION FOR A MAGNETOHYDRODYNAMIC FLOW OF A PERFECTLY CONDUCTING FLUID

  • ZAKARIA, M.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.6 no.2
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    • pp.63-73
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    • 2002
  • The influence of unsteady boundary layer magnetohydrodynamic flow with thermal relaxation of perfectly conducting fluid, past a semi-infinite plate, is considered. The governing non linear partial differential equations are solved using the method of successive approximations. This method is used to obtain the solution for the unsteady boundary layer magnetohydrodynamic flow in the special form when the free stream velocity exponentially depends on time. The effects of Alfven velocity $\alpha$ on the velocity is discussed, and illustrated graphically for the problem.

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A Study on the Tendency of Contemporary Architecture through the Relation Between the Eye and the Gaze (시선과 응시의 관계로 본 현대건축 경향에 관한 연구)

  • Kim, Jin-Mo
    • Korean Institute of Interior Design Journal
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    • v.17 no.5
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    • pp.3-11
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    • 2008
  • 'The eye' and 'the gaze' organize the visual system and distinguish the subject from the others. Recent philosophical thoughts have forcefully argued against the tradition characterized by the domination of the eye that assimilates the alterity of the others to one's own, cancels their alterity, and totalizes their differences within himself. In the speculative discourse modeled on the eye, the alienation of self in its other and the reflection of the object are linked together in such a way as to form a totality in which they are reflected into one's another, leaving absolutely no remainder outside. By contrast to this totalizing tendency of the eye, Sartre and Lacan propose the gaze that becomes constitutive of vision. The modern architecture reinforced subject's eye and clearly separated the others from subject Through Descartes's visual paradigm, space became homogeneous and nature was seized by architecture. However, recently the clear boundary between subject and object is disappearing. Lacan insisted that oneself's eye and the other's gaze are mixed up in human sight This means that the boundary between the subject and the other is indistinct and also the boundary between an object and landscape is meaningless in architecture. The overthrow of gaze in contemporary architecture appears in the form of trans-boundary, translucency and widen architectural notion and expression.