• Journal of applied mathematics & informatics
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• v.29 no.3_4
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• pp.969-980
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• 2011

In this paper, our main purpose is to consider the quasilinear elliptic equation $$div(|{\nabla}u|^{p-2}{\nabla}u)=(p-1)f(u)$$ on a bounded smooth domain ${\Omega}\;{\subset}\;R^N$, where p > 1, N > 1 and f is a smooth, increasing function in [0, ${\infty}$). We get some estimates of a solution u satisfying $u(x){\rightarrow}{\infty}$ as $d(x,\;{\partial}{\Omega}){\rightarrow}0$ under different conditions on f.

• International Journal of Automotive Technology
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• v.8 no.1
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• pp.59-66
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• 2007

High frequency excitation terms in a cam profile can excite vibration of a cam follower system. In this paper, modified smoothing spline curves are used to reduce the high frequency terms. The essential difference between the proposed method and other existing approaches is its ability to make the principal cam motions smooth while still exactly satisfying boundary conditions of follower displacement, velocity and acceleration. The boundary values usually depend on the ramp properties of a cam. Our method, thus, allows designers to smooth the existing cam motion without any damages on its ramp areas. Because the ramp height, velocity and acceleration are maintained exactly, more radical smoothing is possible. An example shows that the proposed method can be a powerful tool of cam profile smoothing, which removes high frequency components in the cam profile excitations without any changes in ramp properties.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.3
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• pp.575-591
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• 2011

We present a novel active contour-based two-pass approach to extract smooth feature regions from a triangular mesh. In the first pass, an active contour formulated in level-set surfaces is devised to extract feature regions with rough boundaries. In the second pass, the rough boundary curve is smoothed by minimizing internal energy, which is derived from its curvature. The separation of the extraction and smoothing process enables us to extract feature regions with smooth boundaries from a triangular mesh without user's initial model. Furthermore, smooth feature curves can also be obtained by skeletonizing the smooth feature regions. We tested our algorithm on facial models and proved its excellence.

• The Korean Journal of Applied Statistics
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• v.6 no.2
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• pp.329-339
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• 1993

Kernel regression is a nonparametric regression technique which requires only differentiability of the true function. If one wants to use the kernel regression technique to produce smooth estimates of a curve over a finite interval, one can realize that there exist distinct boundary problems that detract from the global performance of the estimator. This paper develops a kernel to handle boundary problem. In order to develop the boundary kernel, a generalized jacknife method by Gray and Schucany (1972) is adapted. Also, it will be shown that the boundary kernel has the same order of convergence rate as non-boundary.

• Journal of the Korean Mathematical Society
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• v.33 no.3
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• pp.495-505
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• 1996

Let $\Omega$ be a bounded domain in $R^d, d \geq 1$, with smooth boundary $\partial\Omega$, and let $0 < T < \infty$ be given.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.306-311
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• 2001

Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers(thick, medium and thin)were generated in the Atmospheric Boundary Layer Wind Tunnel at Pusan National University. The thick boundary layer having 670mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer$(\delta=270mm)$ was the natural turbulent boundary layer at the test section with fully long developing length(18m). The thin boundary layer with 36.5mm thickness was generated by on a smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity and the height of the model was $7.9{\times}10^3$. The mean velocity vector fields and turbulent kinetic energy distribution were measured and compared. The effect of boundary layer thickness is clearly observed not only in the length of separation bubble but also in the reattachment points. The thinner boundary layer thickness, the higher turbulent kinetic energy peak around the model roof. It is strongly recommended that the height ratio between model and approaching boundary layer thickness should be a major parameter.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2E
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• pp.37-42
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• 1995

The polar parabolic equation method (Polar PE) which introduces a series of "cascaded" boundary fitting coordinates into the parabolic equation method has been verified as a good numerical method for atmospheric sound propagation over a curved surface and hills. Polar PE is applied here to underwater sound propagation over a sea mountain assuming locally reacting boundary sea bottom and pressure release water surface for the boundary conditions. Calculations are presented for underwater propagation over a 450 m high sea mountain. Feasibility of Polar PE application for underwater sound propagation over a smooth mountain is discussed.

• Communications of the Korean Mathematical Society
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• v.16 no.3
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• pp.405-413
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• 2001

The inverse boundary value problem for the steady state heat equation with convection term is considered in a simply connected bounded domain with smooth boundary. Taking the Dirichlet to Neumann map which maps the temperature on the boundary to the that flux on the boundary as an observation data, the global uniqueness for identifying the convection term from the Dirichlet to Neumann map is proved.

• Journal of the Korean Mathematical Society
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• v.31 no.3
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• pp.401-416
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• 1994

We study the existence of an intermediate solution of nonlinear elliptic boundary value problems (BVP) of the form $$ (BVP) {\Delta u = f(x,u,\Delta u), in \Omega {Bu(x) = \phi(x), on \partial\Omega, $$ where $\Omega$ is a smooth bounded domain in $R^n, n \geq 1, and \partial\Omega \in C^{2,\alpha}, (0 < \alpha < 1), \Delta$ is the Laplacian operator, $\nabla u = (D_1u, D_2u, \cdots, D_nu)$ denotes the gradient of u and $$ Bu(x) = p(x)u(x) + q(x)\frac{d\nu}{du} (x), $$ where $\frac{d\nu}{du} denotes the outward normal derivative of u on $\partial\Omega$.

• Bulletin of the Korean Mathematical Society
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• v.49 no.1
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• pp.1-10
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• 2012

Let ${\Omega}$ be a bounded subset of $\mathbb{R}^n$ with smooth boundary. We investigate the solvability for a class of the system of the nonlinear elliptic equations with Dirichlet boundary condition. Using the mountain pass theorem we prove that the system has at least one nontrivial solution.