• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1631-1638
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• 2007

In this paper, a modeling for the dynamic behavior of a train vehicle is suggested for the prediction of the braking characteristics. In the dynamic modeling, effects of the primary and secondary suspension elements are considered and interactions between two vehicles are also estimated. This study can offer some fundamental results for a further research to enhance the braking performance using active braking control.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.331-336
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• 2008

Electric load components have different characteristics according to the variation of voltage and frequency. This paper presents the load modeling of an electric locomotive by the parameter identification method. The proposed method for load modeling is very simple and easy for application. The proposed load model of the electric locomotive is represented by the combination of the loads that have static and dynamic characteristics. This load modeling is applied to the KTX in Korea to verify the effectiveness of the proposed method. The results of proposed load modeling by the parameter identification follow the field measurements very exactly.

• 한국CDE학회논문집
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• 제7권1호
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• pp.1-8
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• 2002

A Hotchkiss spring has been widely utilized for commercial vehicle. Usually, the Hotchkiss spring has non-linear characteristics, i.e. it has a piecewise spring stiffness as well as hysterisis phenomenon. Therefore, the modeling of the Hotchkiss spring requires many considerations to fulfill satisfactory vehicle kinematic and dynamic relationships. Also, the spring has difficulties in modeling for presenting contact mechanism. In this paper, the modeling technique for the Hotchkiss spring has been descried. The modeling covers non-linear characteristics as well as contact problems for multi-body dynamic simulation. The force-displacement results are compared with experimental and FEM ones. Also, the comparison between three link type leaf spring model and proposed one has been considered in this paper.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.943-946
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• 2003

This paper proposes new SPICE Macro-Model of MTJ(Magnetic Tunnel Junction). This Macro-Model has five I/O terminals, reproduces MR characteristics including hysteresis and behaves correctly to time varying input signals. Furthermore, this Model can be easily modified to various MTJs with different characteristics by simply varying internal parameters.

• 한국정밀공학회지
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• 제29권10호
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• pp.1062-1069
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• 2012

This paper suggests a computational modeling to reflect static/dynamic characteristics of LM bearings. A theoretical study for modeling LM bearings is elucidated by using the Hertz contact theory, the Lagrange's equation of motion, normal mode analysis and a calculation of equivalent moment center. The complex geometry of LM bearings is replaced by a simplified model with eight springs only. The suggested model reflects static and dynamic characteristics of LM bearings without any consideration for the shape of the bed or stages on the LM bearings. The modal experimental results are compared to the simulation results with the suggested computational modeling. The difference between the experiments and simulation is calculated less than 8%.

• 한국농공학회논문집
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• 제56권2호
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• pp.1-9
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• 2014

A modeling system is constructed by integrating an one-dimensional unsteady flow simulation model and a hydrologic model to simulate flood flows in drainage channel networks of paddy field districts. The modeling system's applicability is validated by simulating flood discharges from a paddy field district, which consists of nine paddy fields and one drainage channel. The simulation results are in good agreement with the observed. Particularly, in the verification stage, the relative errors of peak flows and peak depths between the observed and simulated hydrographs range 8.96 to 10.26 % and -10.26 to 2.97 %, respectively. The modeling system's capability is compared with that of a water balance equation-based model; it is revealed that the modeling system's accuracy is superior to the other model. In addition, the simulations of flood discharges from large-sized paddy fields through drainage channels show that the flood discharge patterns are affected by drainage outlet management for paddy fields and physical characteristics of the drainage channels. Finally, it is concluded that to efficiently design drainage channel networks, it is necessary to analyze the results from simulating flood discharges of the drainage channel networks according to their physical characteristics and connectivities.

• 한국지반공학회논문집
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• 제22권10호
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• pp.5-20
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• 2006

본 논문에서는 지하수위 하에서 터널이 시공되는 조건을 대상으로 응력-간극수압 연계 유한요소해석 수행시 모델링 측면에서 중요하게 다뤄져야 하는 내용을 고찰하였다. 먼저 연계해석 수행시 요구되는 지하수위 저하와 지반거동과의 관계에 대한 배경 이론을 알아보았으며, 이를 토대로 모델링 측면에서 해석결과에 영향을 미칠 수 있는 다양한 인자들을 선정하고, 선정된 영향인자에 대한 매개변수 연구를 수행하였다. 지하수위 저하가 동반되는 터널 시공조건에서의 유한요소석 모델링 결과는 지반의 불포화특성 고려여부가 가장 큰 영향을 미치는 것으로 나타났으며 본 고에서는 결과를 종합하여 연계해석 모델링시 중요하게 검토되어야 고려사항을 제시하였다.

• 설비공학논문집
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• 제24권10호
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• pp.718-723
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• 2012

The purpose of this study is to propose modeling method of Underfloor Air Distribution System with reliability and validity by comparing characteristics of modeling methods. For this, the modeling methods of UFAD were selected by investigating various modeling methods of previous researches. Then, simulations were conducted by using EnergyPlus which is dynamic analysis program of building energy. Annual energy consumption for each method was compared with a wide range of indoor thermal loads. As a result, the methodology of reducing internal gains can cause under sizing of the system. It suggests modeling methods to reflect occupied zone air-conditioning, temperature stratification and supply plenum which are the main characteristics of UFAD.

• 한국정보통신학회논문지
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• 제16권8호
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• pp.1599-1605
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• 2012

본 연구에서는 해저의 반사면이나 흡음재와 같이 주파수에 따라 다른 특성을 가지는 매체를 시간영역에서 수치적으로 모델링하고자 시간 해석 기법의 하나인 전달선로행렬법을 이용하였다. 기존의 흡음재의 해석에 응용되던 감쇠를 이용하는 방법의 대안으로 유한임펄스응답 필터를 전달선로행렬법에 도입하였다. 7개의 탭을 가진 FIR 필터로 구현하였으며, 시간 지연, 저역통과필터, 고역통과필터의 시뮬레이션 결과를 이론치와 비교하였다. 여러 시뮬레이션 결과를 통해 흡음재의 주파수에 따른 흡음 특성을 유한임펄스응답 필터를 고려한 하나의 요소만으로 모델링하는 것이 가능하다는 것을 확인할 수 있었다.

• 전기학회논문지
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• 제63권4호
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• pp.469-475
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• 2014

This paper deals with the characteristics evaluations of PM magnetization using stator coil in a Post-Assembly Line Start Permanent Magnet Motor (LSPMM) using a coupled Finite Element Method (FEM) and Preisach modeling, which is presented to analyze the magnetic characteristics of permanent magnets. The focus of this paper is the characteristics analysis relative to magnetizing direction and quantity of permanent magnets due to the eddy current occurring in the rotor bar during magnetization of Nd-Fe-B.