• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.121-129
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• 2008

In this paper, we present a fast analysis of multilayer microstrip fractal structure by using the fast multipole method (FMM). In the analysis, accurate spatial green's functions from the real-axis integration method(RAIM) are employed to solve the mixed potential integral equation(MPIE) with FMM algorithm. MoM's iteration and memory requirement is $O(N^2)$ in case of calculation using the green function. the problem is the unknown number N can be extremely large for calculation of large scale objects and high accuracy. To improve these problem is fast algorithm FMM. FMM use the addition theorem of green function. So, it reduce the complexity of a matrix-vector multiplication and reduce the cost of calculation to the order of $O(N^{1.5})$, The efficiency is proved from comparing calculation results of the moment method and Fast algorithm.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.1 s.47
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• pp.17-23
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• 2006

The research on strong ground motions became important recently due to more severe requirement of seismic design for the domestic buildings and structures. The empirical Green's function method, which uses similarities between small and large earthquakes, was applied to make synthetic ground motions. That method was applied to the 2 earthquakes which occurred sequently in time within narrow area in Japan. The strong ground motions for the virtual earthquake (magnitude 6.5) were synthesized using those observed from the magnitude 4.7 earthquake. Then, the synthesized ground motions (acceleration, velocity, and displacement) were compared to those observed from real earthquake (magnitude 6.5). The results showed that the general shapes of waveforms in time domain and the Fourier spectrum In frequency domain from synthesized ground motions (acceleration, velocity, and displacement) are similar to the observed strong ground motions within acceptable degree. The peak values of 3 kinds of synthesized strong ground motions in time domain are comparable between the synthesized and the real strong ground motions, especially only about 9% difference in acceleration peak value.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.3
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• pp.378-384
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• 1997

In curing process of tire, contact and slip occurs between green tire and curing bladder. The curing process is a critical step in the manufacture of tires. In this investigation, curing bladder shaping is examined using a finite element method. Specifically, a finite element model between the inner part of green tire and the outer part of curing bladder is generated using contact element and curing bladder is generated using incompressible element. Numerical analysis are performed on two different bladder types, different overall outer diameters of curing bladder and different heights of curing bladder. Numerical results show that contact pressure is increased by using toroidal type of curing bladder, increasing overall diameter and increasing height of curing bladder. To obtain natural equilibrium carcass line, there is a requirement in increasing contact pressure of the section between side and bead.

• 전자공학회논문지 IE
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• v.46 no.3
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• pp.12-18
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• 2009

In this paper, we developed white balance correction processor for Full Color LED Display System which could be display uniformity color and soft light by adjusting brightness of red, green, blue pixel, individually. This processor correct brightness by calculating operating current of each pixel(red, green, blue LED) on the basis of characteristic curve of LED device when we named "a" as a specific characteristic value, "b" as a brightness correction value according to using time, "X" as a operating current value, and "Y" as brightness value. As the results, we solved the reduction problem of brightness for long used LED devices, according to increase entire mean of brightness value by adjusting "b" value from the brightness characteristic function.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.1
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• pp.16-22
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• 1976

Broadband operation of Y-junction microstrip circulator withlnonreciprocal device is predicteg by Rosenbaum using Bosma's Green function analysis. The anslysis has been modified to enable the scattering matrix and therefore the circulator bandwidth, to be found. The width of the coupling transmission lines is found to be a significant design parameter${\psi}$. A comparison of experimental and theoretical results for the 3-port junction shows that wide lines and a smaller 7.5U than usual disk radius can be used to obtain broadband operation. Circulator operates in the frequency band 5-11 GHz. The obtained maximum insertion loss is 0.5dB and the isolation is more than 15dB.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.5
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• pp.502-510
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• 2007

The present study is to estimate the effect of diffracted wave fields inside a harbor, around harbor entrance and outer breakwater, when a navigation channel is dredged in the vicinity of the a harbor entrance. The wave field of the problem is considered to be two-dimensional plane and the configuration of the submarine pit on the sea bed is designated by a single rectangular type. The numerical simulation is performed by using the solution of the Greet function based on the boundary integral equation. The results of this study is illustrated by applying the normal incidence and partially reflecting boundaries.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.640-647
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• 1998

Microstrip patch antennas are analyzed by a multiresolution wavelet method. The spectral Green's dyad of the structure is obtained and its joint spatial-spectral domain representations are presented. Based on the joint spatial-spectral domain representation, we show that the spectral-domain wavelets are useful in the analysis of this problem. We obtain the matrix equations of the integral equations of this Green's dyad by using the method of moment(MoM), and efficiently solve the problem using the spectral domain wavelet transform concepts in conjuction with the conjugate gradient method. The results for a single-layered square patch are compared with those of conventional MoM and CG-FFT.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.5
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• pp.39-45
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• 1978

This paper described on the varactor tuning Gunn oscillator for X band. Analyzed the coplanar 2 post case using the dyadic Green's function then derived the obstacle network for the incident TE10 mode. For the electronical tuning, used the tuning varactor diode which has a high speed dynamic response characteristic and high Q. Oscillation frequency, switching mode, and stable oscillation point were calculated by the computer simulation. In the expriments, switching mode was occurred at 18 mm, 32.5 mm of the short tcircuit position, respectively. The general characteristics of the varactor tuning Gunn oscillator were abruptly changed by the moving of the short circuit and the variation of the bias voltage.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.2
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• pp.78-85
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• 1994

Impact forces are acting on the fore part of a body entering water and those are function o the shape of the fore part and entrance angle. In this paper, impact forces are computed for the flat faced body with arbitrary entrance angle The geometric characteristics of the wetted surface of the body are complicated. The surface is divided into several smooth parts and each of them is represented by a bi-cubic B-spline. The free surface condition, $\phi=0$, is applied at the undisturbed free surface and he boundary value problem is analized by using Green's function.

• Journal of KIISE:Software and Applications
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• v.27 no.10
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• pp.1054-1061
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• 2000

영상 정합은 물리적으로 유사한 영상 내의 영역들을 기하학적으로 일치시키는 처리이며 지형 정보, 영상검색, 원격탐사, 의료영상 등의 많은 영상처리 응용에서 사용된다. 영상 정합에 관한 연구는 주로 회전, 크기, 위치 등의 인자 추출에 소요되는 시간과 정확성에 중점을 두어 왔다. 본 연구에서는 영상의 특징 점들에 대한 일차 고유벡터의 방향 분포를 히스토그램으로 표현하고 이를 비교 분석함으로써 정합하는 방법을 제안한다. 일차 고유벡터를 이용함으로써 특징 묘사의 단순성을 제공하고. 히스토그램을 이용하여 정합 인자를 미리 추정함으로써 정합 인자 추출 시 목적함수의 연산에 소요되는 비용을 현저하게 줄였다. 본 연구의 결과를 평가하기 위해 제안한 방식을 일반 영상과 ICG(IndoCyanine Green)망막 영상에 적용한 결과를 보여주고 목적함수의 연산횟수와 시간 복잡도를 기존의 방법들과 비교하였다.