• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.1922-1927
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• 2003

Nonlinear normal mode (NNM) vibration, in a nonlinear dual mass Hamiltonian system, which has 6$\^$th/ order homogeneous polynomial as a nonlinear term, is studied in this paper. The existence, bifurcation, and the orbital stability of periodic motions are to be studied in the phase space. In order to find the analytic expression of the invariant curves in the Poincare Map, which is a mapping of a phase trajectory onto 2 dimensional surface in 4 dimensional phase space, Whittaker's Adelphic Integral, instead of the direct integration of the equations of motion or the Birkhoff-Gustavson (B-G) canonical transformation, is derived for small value of energy. It is revealed that the integral of motion by Adelphic Integral is essentially consistent with the one obtained from the B-G transformation method. The resulting expression of the invariant curves can be used for analyzing the behavior of NNM vibration in the Poincare Map.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.239-242
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• 2000

The purpose of this paper is to establish an effective inspection system by using OMM(ON-Machine Measurement) system. This allows us to reduce the manufacturing lead time by separating the inspection process from manufacturing system. As a first step, the inspection process planning is accomplished by determining the number of measuring points, their locations, measuring path and their sequence. Subsequently, we generate measuring G-codes to be transferred to the machining center through RS232C, and then the inspection process will be performed for each shape. Analysing obtained measuring data, the dimensional tolerance will be validated.

• 한국소음진동공학회논문집
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• 제14권11호
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• pp.1101-1106
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• 2004

There are many difficulties to get the scattered field generated by obstacle which has arbitrary shape or irregular surface impedance by using analytic solution or numerical methods. In this study, we propose a method of which makes acoustic scattering holography that can predict the far-field scattered field based on nearfield measurements. This method provides the scattered fields of each wave-number components of incident fields. We express the relationship of wave-number components between incident fields and scattered fields using scattering matrix which is transfer matrix of wave-number components. Lastly, we prove the relation between wave-number components of incident and scattered field by experiments. The errors which are caused by measurements and decomposition methods are also analyzed.

• 전자공학회논문지A
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• 제32A권9호
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• pp.106-113
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• 1995

The radiation characteristics of the subreflector of a shaped dual offset reflector antenna are analyzed by the uniform theory of diffraction(UTD). The discrete shaped subreflector profile is transformed into an analytic function by the global interpolation. To obtain the first and the second derivative terms on the surface, the local interpolation method is used. The reflection point needed for the geometrical optics(GO) is found by using the multi-dimensional function minimizing algorithm. The radiation pattern of a Gregorian type shaped subreflector is presented. The characteristics of the radiation patterns for various feed edge taperings and frequencies are examined.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1005-1011
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• 2007

The brake system of train must posses the large braking effort in order to stop the train safely within the limited traveling distance. But, the excessive braking effort has been deteriorated the ride comfort due to high level of deceleration and jerk, and sometimes occurred the skid, because the applied braking force exceeds the allowable adhesive force. This skid causes not only to increase the stopping distance but also to deteriorate the safety of train and damage the rail surface by wheel flat. In the present paper, the braking force for disc brake of Korea High Speed Train (HSR350x) was measured through on-line test and the adhesion force was estimated by using the analytic model in the skid condition. Also, we have discussed the relationship between the actual disc brake force and the adhesion force in real skid condition.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.214-219
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• 1998

Analytic and experimental methods have been used for the characterization of flow behavior of semi-solid Al2024 alloy. Backward extrusion experimnet was chosen to avoid the crack on the unconstrained surface. The material constants for the flow stress by the upper bound technique that agreed with experimental results were determined. The various material constants obtained for al temperature range above the solidus temperature have been fitted and represented in the function of temperature and solid fraction. The obtained result has good agreement only in the high solid fraction.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1998년도 춘계 학술대회논문집
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• pp.43-48
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• 1998

The development of unsteady three-dimensional incompressible viscous solver based on unsteady physical curvilinear coordinate system is presented. A 12-point finite analytic scheme based on local uniform grid spacing is extended for nonuniform grid spacing. The formulation of a condition is suggested to avoid the oscillation of the series summations produced by the application of the method of separation of variables. SIMPLER and pressure Poisson equation techniques are used for solving a velocity-pressure coupled problem. The matrix is solved using the Generalized Minimal RESidual (GMRES) method to enhance the convergence rate of unsteady flow solver and the Kinematic boundary condition of a free surface flow. It is demonstrated that the numerical solutions of these equations are less mesh sensitive.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.590.2-590
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• 2001

This study was performed to evaluate the temperature rise on various position of the Buchanan plugger, the peak temperature of plugger's type and the temperature change by its touching time of heat control spring. The System B (Model 1005, Analytic Technologies, USA) and the Buchanan pluggers of F, FM, M and ML are used for this study. The temperature was set to $200^{\circ}C$. The power level on it was set to 10. The heat control spring was touched for 1,2,3,4 and 5 seconds respectively. (omitted)

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.878-882
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• 2004

지하수를 이용한 물 문제 해결 방법은 여러 수공학자들에 의해 연구되어 왔고 많은 성과를 이루었다. 하지만, 과도한 지하수 개발은 새로운 공학적 문제를 야기하게 되어 각 수자원에 내한 개별적인 분석 단계를 지나 여러 수자원을 연계하여 이용할 수 있는 기법들이 연구되고 있다. 이 방법 중 하나로 지표수와 지하수를 연계 이용하는 방법이 연구되었고, 개발 대상 지역에 대한 우선순위 결정을 위해 계층분석과정(Analytic Hierarchy Process, AHP)이 적용되었다. 이리한 적지 분석을 위한 시스템(SASCU)을 GIS와 연계하여 개발함으로써 개랄 가능 후보지에 대한 개발 우선순위 결정에 도움이 괼될것으로 사료된다.

• 천문학논총
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• 제24권1호
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• pp.43-51
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• 2009

이 연구에서는 임의의 밀도 분포를 갖는 성간 먼지 구름에 의해 산란되는 산란광을 분석할 수 있는 몬테카를로 시뮬레이션 코드를 개발하였다. 개발된 코드의 신뢰성을 확보하기 위해 구 대칭의 성간먼지 구름의 중심에 별이 있고, 별빛이 얼마만큼 산란되어 나오는 지 계산하여 Code (1973)의 결과와 비교하였으며, Code의 근사식과 매우 잘 일치하는 결과를 주는 것을 확인하였다. 이 코드는 우리 은하뿐만 아니라 외부은하의 경우에도 손 쉽게 확장이 가능하다. 개발된 코드는 과학위성 1호로 관측된 원자외선 연속복사광의 분석에 적용하여 성간먼지 구름의 특성과 우리 은하의 복사장의 분포를 연구하는 데 사용하고자 한다.