• 대한전자공학회논문지
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• 제24권6호
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• pp.948-955
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• 1987

The model reduction method of the high order linear time invariant systems is proposed. The continuous fraction expansion of Auxiliary denominator polynomial is used to obtain denominator polynomial of the reduced order model, and the numerator polynomial of the reduced order model is obtained by equating the first some moments of the original and the reduced order model, using simplified moment function. This methiod does not require the calculation of the reciprocal transformation which should be calculated in Routh approximation, furthemore the stability of the reduced order model is guaranted if original system is stable. Responses of this method showed us good characteristics.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.349-352
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• 1999

In this paper, we present simplified fault set which is made by analyzing fault relation to design specification in CMOS operational amplifier. The hard fault is easily modeled because an effect of hard fault is out of all design specification. However, the soft fault is not easily modeled because an effect of soft fault on design specification is varied according to position and depth of fault. We simulated hard and soft fault by HSPICE, varying threshold voltage and W/L ratio from 90% increase to 90% decrease. The decrease of test time and the production of high reliability mixed-mode IC are possible by the proposed fault set.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.185-192
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• 2003

This study presents the Optimum Evaluation of PS Concrete Deck and High Strength Two Plate Girder System. Recently, for the simplification of structure and the long length of bridge, a small number girder bridge which minimized a number of girder by two is much designed and constructed. For the structural analysis, a finite element formulation considering with even the matter of torsion in the three-dimensional problem is presented. And connectively, for the design of optimum section, an algorithm of optimum design is developed. The section of a small number girder bridge which constituted of two girders and PS Concrete Deck is optimized by using optimum program developed in this study. and two girders bridge refered in this study is proved a efficiency and a economy by being compared and checked to the general plate girder bridge with five girder and Reinforced Concrete Deck.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1456-1459
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• 2007

Protective equipments have a very important protection role in power accident on catenary line. These equipments are installed on electrical pole. The poles have complicated with many bands(moveable bracket, branch wire anchor, shield wire, etc). So we have improved bands and installed bands on pole to test technical condition. The Result has showed effectiveness due to fixed position change of fault protective wire and to improve band shape. For example, reduction of band made cost, simplification of installing, correct position of protective wire and shield wire.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1326-1331
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• 2009

Drying process in the cylindrical thin film layer of sludge with the thickness less than a few millimeters has been investigated. Thin film drying is specially designed and used to dry the viscous materials like sewage sludge. The thin film layer of sludge is dried on the metallic cylindrical surface through which thermal energy is supplied to the layer during drying. The wall temperature is assumed to be constant during drying in the present study for the simplification. In order to solve the equations, the mass transfer rate on the drying surface should be determined. The mass flux of evaporated water vapor on the surface is estimated with the formulation given in the literature. The effect of some physical parameters on drying has been examined to figure out the drying characteristics of the sludge layer.

• 설비공학논문집
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• 제21권10호
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• pp.575-582
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• 2009

The optimum rotation speed of a desiccant rotor is studied theoretically based on a theoretical solution to the heat and mass transfer processes in the desiccant rotor. A simple correlation equation for the optimum rotation speed is derived to show the effects of various parameters including the thermo-physical properties, the geometric dimension, and the operating condition of the desiccant rotor. The theoretical result is compared with existing experimental data to validate the linearization and simplification included in the solution procedure. Based on the theoretical solution, the effects of major parameters on the optimum rotation speed are studied and the fundamental mechanism of the influences is investigated.

• 한국광학회지
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• 제5권4호
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• pp.439-444
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• 1994

임의의 2차원 표면양각 유전회절격자에 의한 일반적인 회절현상을 엄밀한 3차원벡터 결합파해석으로 다루는데 있어서 핵심적인 역학을 하는 행렬의 고유값문제가 항상 1/4 크기의 행렬에 대한 것으로 단순화되어, 컴퓨터의 계산시간과 기억용량의 요구를 현저히 줄일 수 있다는 것을 보였다. 한편, 체적형 회절격자에 있어서는 이와 같이 단순화할 수 없음을 논의하였다.

• 한국수학사학회지
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• 제20권3호
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• pp.43-58
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• 2007

혼자 즐겨서 하는 놀이의 하나로서 동양에서는 징검돌 게임이나 원앙놀이가 있었고, 서양에서는 페그 퍼즐이나 솔리테르가 있었다. 본 논문에서는 이들 중 가장 기본적인 게임을 바둑돌 게임으로 부르고, 학생들에게 문제의 다양한 해결 전략을 경험할 수 있는 기회를 제공하기 위해 바둑돌 게임을 교수학적으로 활용하는 방안을 제시하고자 한다. 먼저, 바둑돌 게임의 가장 기본 형태인 (3, 3)으로 시작하여, 단순화, 일반화, 확장의 단계로 문제를 제시한 후, 해결 전략으로서 시행착오를 통한 조작, 다이어그램이나 기호의 활용, 패턴 찾기와 일반화, 발산적 사고와 확장 등을 살펴본다.

• 한국정밀공학회지
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• 제20권10호
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• pp.226-232
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• 2003

Difficulties in the finite element modeling of human spine are evaded by using a stiffness matrix element whose properties can be characterized from experimentally measured stiffness of functional spinal units. Relative easiness is in that inter-vertebral discs, ligaments, and soft tissues connecting vertebrae do not need to be modeled as they are. The remarkable coupling effect between distinct degrees of freedom induced by the geometric complexity can be accommodated without much effort. An idealized block model with simple geometry for vertebra is employed to assess the feasibility of this method. Analyses are performed in both levels of motion segment and spinal column, and the result is compared with that from detail model. As far as the global behavior of spine is concerned, the simplification is found not to aggravate inaccuracy only if sufficient experimental data is provided and interpreted properly.

• Tribology and Lubricants
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• 제17권1호
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• pp.33-39
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• 2001

A method of calculating wear volume is developed using the signal processing technique. The lowpass filter with Fourier transform and the “windowing” are implemented in the method. User-defining feature is also included in determining the cutoff frequency of the low-pass filter and the baseline for the volume integration. Commercial software, MatLab, is used for the programming. Since the method uses the original wear data without simplifying the wear shape, it can give a further accurate result than the previously utilized methods, which often adopted the simplification. It becomes further powerful if the contacting body has a general shape rather than that gives well-formed surface traction (e.g., the Hertzian). The validation of applying the average surface roughness, Ra, to the “windowing” and the baseline for volume integration is discussed.