• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.539-545
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• 2001

This paper proposes a static synchronous series compensator based on multi-bridge inverter. The proposed system consists of 6 H-bridge modules per phase, which generate 13 pulses for each half period of power frequency. The dynamic characteristic was analyzed by simulations with EMTP code, assuming that it is inserted in the 154-kV transmission line of one-machine-infinite-bus power system. The feasibility of hardware implementation was verified through experimental works using a scaled model. The proposed system does not require a coupling transformer for voltage injection, and has flexibility in expanding the operation voltage by increasing the number of H-bridge modules.

• 설비공학논문집
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• 제15권5호
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• pp.337-345
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• 2003

In the case of heat exchangers operating under frosting condition, the growth of frost layer causes the heat exchanger to increase the thermal resistance and pressure loss of the air flow. In this paper, a transient characteristic prediction model of the heat transfer for multi inverter heat pump with frosting on its surface was presented taking into account the change of the fin efficiency due to the growth of the frost layer. In this dynamic simulation program, which was peformed for a basic air conditioning system model, such as evaporator, condenser, compressor, linear electronic expansion valve (LEV) and bypass circuit. The theoretical model was driven from the obtained heat transfer coefficient and mass transfer coefficient, independently. And we consider heat transfer performance was only affected by a decrease of the wind flow area. The calculated results were compared with some cases of experiments for frosting conditions.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.287-293
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• 2010

본 연구에서는 개방형 로켓엔진시스템의 제어시스템을 구성하기 위한 선행연구로서, 시동특성을 예측하기위해 Simulink 모델을 구성하였다. 구성품별 동특성 모델을 바탕으로 로켓엔진시스템의 예측 프로그램을 구성하였으며, 대상으로 하는 시스템의 천이 작동상태에서의 동특성 변화의 예측과 더불어 그 모델링의 타당성 검증을 위하여 실제 개방형 로켓엔진 상사모델의 수류실험을 통해 실험적으로 측정하여 비교하였다. 또한 Simulink모델이 제어시스템을 구성하기위해 적합한지를 판단하기위해 기 수행된 천이 동특성 예측 프로그램의 결과와 비교하였고 검증하였다.

• 정보저장시스템학회논문집
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• 제9권2호
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• pp.51-55
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• 2013

HDD has been easily exposed to the external shock and vibration because HDD has to apply to mobile devices. Therefore, the stiffness of base has been the important factors for the design of HDD. To improve the stiffness of base, the frame was applied to the base. First, the finite element model of the base was constructed. Then, the FE model was verified by modal analysis. Drop test was performed to confirming the shock simulation model. The dynamic characteristic of original base which is verified is compared with the base which is applied the frame through modal analysis and shock analysis.

• 한국추진공학회지
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• 제15권1호
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• pp.45-54
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• 2011

액체로켓엔진 시스템에 대한 동특성 예측 프로그램을 작성하였다. 이 프로그램을 통해 얻은 펌프 시동 시 압력 및 유량 변화 결과를 수류시험장치를 구축하여 실험적으로 검증하였다. 수류시험장치는 실제 개방형 액체로켓엔진 추진제 공급 계통에서 구성품의 형태와 배치위치, 가스발생기와 주연소실로 분기되는 유량비를 기준으로 모사되었다. 동특성 예측 프로그램의 작성을 위해 구성품별 동특성 모델링을 수행하고 엔진 시스템을 기준으로 각 모델링을 순차적으로 통합하였다. 예측 프로그램에 구성품의 동특성 파라미터를 측정 반영하였고 천이 작동 상태에서 엔진 시스템 내의 작동 파라미터 변화 결과를 실험적으로 측정하고 비교 분석하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.147-154
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• 2001

Dynamic behavior of high speed train is very important because the high speed train should be safe and satisfied with the ride comfort. An eddy current brake system is mounted on trailer bogie and wheelset. The eddy current braking force longitudinally exerts on the articulated trailer bogie and the attraction force vertically exerts on the wheelset. Because a frame of eddy current brake system is flexible, these forces generate the vertical vibration at middle point of the frame. Also, the vibration change the vertical clearance between an electromagnet and top of rail which affect the magnitude of braking and attracting forces. Therefore, the dynamic behavior of the eddy current braking system must be predicted for design the dynamic characteristic of its mounting system when normally operate on rail which have irregularity. Vampire program is used for Prediction of the dynamic behavior of an eddy current braking system.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.35-38
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• 2007

액체로켓엔진(Liquid Rocket Engine) 의 천이성능 예측을 위해 선행연구 되었던 LRE 시스템 모듈화 프로그램의 결과를 살펴보고, 일본의 로켓엔진 동적 해석 프로그램(Rocket Engine Dynamic Simulator)의 엔진 시스템 동적 해석 방법과 모델링에 대해 고찰하였다. LRE 시스템 모듈화 프로그램에서는 각 구성품에 대한 설계 인자를 수학적으로 모델링하였고 구성품 간의 유량과 압력을 매칭시켜 통합하여, 로켓엔진 시스템의 요구조건을 만족하는 각 구성품에 대한 주요 설계 파라미터를 도출하는 과정에 관하여 논의하였다. 로켓엔진 시스템을 유한한 배관요소들의 연결로 모델링하고, 시간의 함수로 표현되는 보존방정식을 적용하여 터보펌프, 밸브, 오리피스，추력실 등 유체기기의 작동 특성을 모사하는 동특성 설계 과정에 관하여 고찰한다.

• 대한기계학회논문집A
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• 제32권12호
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• pp.1146-1152
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• 2008

In the initial stage of guided missile launching, the dynamic stability of a missile is highly influenced by disturbances from the outside and interferences among the launching system parts. This research develops a program for guided missile launching system analysis. Random variables are used to analyze quantitatively the missile characteristic response. An example of results with the program applied into a specific System is presented to demonstrate the effectiveness of the propose method.

• 소음진동
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• 제11권2호
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• pp.346-353
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• 2001

In this study dynamic characteristic of catenary system that supplies electrical power to KTX Korean high-speed trains are investigated. A simulation program based on 3-span and 6-span finite element models of the catenary is developed. The influences of the various design parameters on the dynamic responses of the catenary are determined. The main design parameters include tension on the contact and messenger wires and the stiffness of the droppers connecting the two wires. The vibrational responses are primarily determined by the reflections of the propagating wave, and the dropper stiffness is found to be the dominant factor that influences overall dynamic characteristics of the catenary.

• 동력기계공학회지
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• 제16권1호
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• pp.24-29
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• 2012

Recently, in the movie theater, the special chair is installed to maximize the viewing effect of movies. It is structured to convey a vibrational stimulus to a specially-designated parts of human body by attaching a vibration transducer to a existing theater chair. This paper describes the analysis of the vibration transfer characteristic of a foaming sponge seat for the design of the special chair. We could not apply the structural analysis S/W because it is difficult to obtain the mechanical properties and damping coefficients of the various type sponges. And then we computed the transfer functions by the global curve fitting program based on experimental modal analysis. The experimental response results comparatively coincide with those by the global curve fitting program. We also could obtain the natural frequencies, the modal damping coefficient ratio, the modal vectors and the whole transfer functions. Therefore we could analyze the dynamic characteristic for design of foaming sponge seat.