• Honam Mathematical Journal
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• v.41 no.4
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• pp.823-835
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• 2019

A solution for Nevanlinna-Pick interpolation problem with low complexity is constructed via non-recursive method. More precisely, a stable rational function satifying the given interpolation data in the complex right half plane is found by solving a homogeneous interpolation problem related to a minial interpolation problem for the given data in the right half plane together with its mirror-image data.

• Structural Engineering and Mechanics
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• v.77 no.4
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• pp.473-479
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• 2021

The propagation of plane waves in a linear, homogeneous and isotropic nonlocal generalized thermoelastic solid medium is considered in the framework of Lord and Shulman generalization. The governing field equations are formulated and specialized in a plane. Plane wave solutions of governing equations show that there exists three plane waves, namely, P, thermal and SV waves which propagate with distinct speeds. Reflection of P and SV waves from thermally insulated or isothermal boundary of a half-space is considered. The relevant boundary conditions are applied at stress free boundary and a non-homogeneous system of three equations in reflection coefficients is obtained. For incidence of both P and SV waves, the expressions for energy ratios of reflected P, thermal and SV waves are also obtained. The speeds and energy ratios of reflected waves are computed for relevant physical constants of a thermoelastic material. The speeds of plane waves are plotted against nonlocal parameter and frequency. The energy ratios of reflected waves are also plotted against the angle of incidence of P wave at a thermally insulated stress-free surface. The effect of nonlocal parameter is shown graphically on the speeds and energy ratios of reflected waves.

• Korean Journal of Mathematics
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• v.30 no.4
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• pp.643-652
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• 2022

In this paper, we will describe affine homogeneous domains in the complex plane. For this study, we deal with the Lie algebra of infinitesimal affine transformations, a structure of the hyperbolic metric involved with affine automorphisms. As a consequence, an affine homogeneous domain is affine equivalent to the complex plane, the punctured plane or the half plane.

• The Journal of the Acoustical Society of Korea
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• v.21 no.4E
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• pp.183-188
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• 2002

In this paper, the strong in-plane vibration has been experimentally observed at the end of a finite cylindrical shell. The strong in-plane vibration was generated by the evanescent wave field, which was excited along about half the length of the shell. The evanescent waves were generated due to mode conversion of elastic waves at the ends of the cylindrical shells. The results show that the strong in-plane end vibration can be generated in cylindrical shells.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.4
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• pp.771-776
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• 2009

Let (H, g) denote the upper half plane in $R^2$ with the Riemannian metric g := ($(dx)^2$ + $(dy)^2$)$/y^2$. First of all we get a necessary and sufficient condition for a diffeomorphism $\phi$ of (H, g) to be a harmonic map. And, we obtain the fact that if a diffeomorphism $\phi$ of (H, g) is a harmonic function, then the following facts are equivalent: (1) $\phi$ is a harmonic map; (2) $\phi$ is an affine transformation; (3) $\phi$ is an isometry (motion).

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.235-239
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• 2001

In this paper, we propose an optical configuration of a reflective AFLC display mode using a half-wave AFLC cell in which inplane tilt angle is $22.5^{\circ}C$. To check the validity of our design, we fabricate a reflective half-wave AFLC cell of which the in-plane tilt angle is $24.9^{\circ}C$, and measure viewing angle and visible spectra characteristics. In the results, the half-wave AFLC cell in the reflective configuration exhibits wide viewing-angle as well as high brightness and contrast. trast.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.8 s.111
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• pp.788-794
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• 2006

In this paper, a Sommerfeld integral for an impedance half-plane is considered, which is one of classical problems in electromagnetic theory. First, the integral is evaluated into two series representations which are expressed in terms of exponential integral and Lommel function, respectively. Then based on the Lommel function expansion, an exact, closed-form expression of the integral is formulated, written in terms of incomplete Weber integrals. Additionally, based on the exponential integral expansion, an approximate expression of the integral is obtained. Validity of all formulations derived in this paper is demonstrated through comparisons with a numerical integration of the integral for various situations.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.1-7
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• 1989

For H-polarized incident plane wave, an exact integral expression for the scattered field by an inversely tapered resistive half plane is obtained by using Kontorovich-Lebedev transform. Uniform asymptotic results available for all angles are obtained, and non-uniform asymptotic results which provide the ray-optical interpretation of the calculated scattered field are also obtained. The edge diffraction patterns for several values of inverse proportionality of resistivity are shown. We find out that the results are in agreement with physical reasoning.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.24 no.1
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• pp.93-102
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• 2020

The concept of temperature distribution in inhomogeneous semi-infinite solids is examined by making use of direct integration method. The analysis is done on the solution of the in-plane steady state heat conduction problem under certain boundary conditions. The method of direct integration has been employed, which is then reduced to Volterra integral equation of second kind, produces the explicit form analytical solution. Using resolvent- kernel algorithm, the governing equation is solved to get present solution. The temperature distribution obtained and calculated numerically and the relation with distribution of heat flux generated by internal heat source is shown graphically.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.4
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• pp.283-288
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• 2002

This paper has shown that the impulse and the unit step responses of 2nd-order systems can be computed by an analytic method. Three different 2nd-order systems are investigated: the prototype system, the system with one LHP(left half plane) real zero and the system with one RHP(right half plane) real zero. It has also shown that the effects of the LHP or the RHP zero are very serious when the zero is getting closer to the origin on the complex plane. Based on these analytic results, this paper has presented two sufficient and necessary conditions for 2nd-order linear SISO(single-input/single-output) stable systems to have the nonovershooting and the monotone nondecreasing step response, respectively. The latter condition can be extended to the sufficient conditions for the monotone nondecreasing step response of high-order systems.