• 풍력에너지저널
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• 제2권1호
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• pp.82-89
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• 2011

his dissertation is on power control system for MW-class wind turbine. Especially, the control purpose is reduction in electrical power and rotor speed. The base control structure is power curve tracking control using variable speed variable pitch operational type. For the reduction of fluctuations, more control algorithm is needed in above rated wind conditions. Because general pitch control system is low dynamic response as compared with the wind speed change. So, this paper introduces about the pitch feed forward control to minimize fluctuations of the electrical power and rotor speed. To maintain rated electrical power, the algorithm of feed forward control adds feed forward pitch amount to the pitch command of power curve tracking control. The effectiveness of the feed forward control is verified through the simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.501-504
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• 2000

In this paper the PC power supply is studied from the point of system stability. The power stage model of a multiple output forward converter with weighted voltage mode control is derived including all the major parasitic components and the small signal model is also derived. Determination of the weighting factors and a design procedure for the loop compensation are presented. Finally the model is verified through the simulation of three output forward converter with SABER.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.439-444
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• 2001

We provide methods to simulate noise propagation for an outdoor environment. Forward tracing method traces sound vectors from sources to receivers while geometry based computation finds all possible sound propagation between sources and receivers geometrically. We discuss defects in relying on a forward tracing method, and suggest a geometry based method. Geometry based method considers all possible direct and indirect(propagation via limited number of reflections) sound propagation saving computational time compared to forward sound tracing. Our simulation results are visualized using VRML(Virtual Reality Modeling Language).

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.386-389
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• 2002

This paper proposes the boost input type active clamp forward ZVS(zero voltage switching) DC-DC converter which can provide high efficiency and improved EMI characteristics. Moreover, it has active clamp circuit for reducing the voltage stress and zero voltage switching technique for minimizing switching loss. The detailed operation principles and the simulation results are presented.

• International Journal of Contents
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• 제10권1호
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• pp.23-28
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• 2014

When developing a classifier using various objective functions, it is important to compare the performances of the classifiers. Although there are statistical analyses of objective functions for classifiers, simulation results can provide us with direct comparison results and in this case, a comparison criterion is considerably critical. A Receiver Operating Characteristics (ROC) graph is a simulation technique for comparing classifiers and selecting a better one based on a performance. In this paper, we adopt the ROC graph to compare classifiers trained by mean-squared error, cross-entropy error, classification figure of merit, and the n-th order extension of cross-entropy error functions. After the training of feed-forward neural networks using the CEDAR database, the ROC graphs are plotted to help us identify which objective function is better.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 압출 및 인발 심포지엄
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• pp.79-82
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• 1999

This paper presents a study of cold combined forward-backward extrusion product. The case of product with thin wall in piercing process occur defects of deformation and breakdown during piercing process and the center web of product with thin thickness cause flow defect. Such defect is made by the difference of material flow. Methods of the material flow control in the two directions and forming process to remove this flow defect is proposed. The effectiveness of the proposed methods is examined by comparison experiment and finite element simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.387-392
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• 1990

In this papers, SPICE which is widely used in analysis of general circuit and simulation in electric and electrical field is applied to DC-DC converter. Be selected Forward which is widely used as SMPS(Switched Mode Power Supply) amang DC-DC converter, and showed the aveformer, we know that the converter is operated in normal. Including the control circuit in converter, by controlling the duty ratio of switch, we know that the output voltages is staple from the transient state of convwrter. Also, comparing SPICE simulation with experiment, the validity of simulate is showed.

• 전자공학회논문지B
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• 제28B권5호
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• pp.411-420
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• 1991

In this paper, SPICE program which is widely used in analysis of general circuit on electronic and electrical field has been applied to DC-DC converter. We have selected Forward type which is widely used us SMPS(Switched Mode Power Supply) of various electronic equipments, and have confirmed the waveforms of circuit operation, transfer of energy and resetting in transformer. And the procedure which the output voltage of converter, including the control circuit, has been stabilized from the transient state to the steady state by controlling the duty ratio of switch is presented. We have compared SPICE simulation with experiment and have verified the validity of SPICE simulation.

• 한국정보통신학회논문지
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• 제12권2호
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• pp.336-342
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• 2008

Amplify and forward(AF)와 decode and forward(DF)의 두 가지 모드에 대하여 네트워크의 네트워크 수명을 극대화할 수 있는 단순한 구조의 전력할당 방식을 제안한다. 네트워크 수명을 극대화하기 위해서는 전송전력을 최소화하는 것뿐만 아니라 전력을 네트워크의 모든 노드에게 균등하게 할당하는 것이 중요하다. 제안된 전력할당기법에서 송신전력은 노드의 잔여전력에 비례하고 목적지 노드에서 요구되는 수신 SNR을 만족하도록 할당된다. 본 논문에서는 AF와 DF의 두 가지 모드에 대하여 할당전력을 계산하였고 시뮬레이션을 통하여 그 성능을 분석하였다. 시뮬레이션 결과 제안된 전력할당 방식은 균등할당방식에 비하여 네트워크 수명을 크게 증가시킬 수 있었다.

• 인터넷정보학회논문지
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• 제12권6호
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• pp.35-42
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• 2011

무선 네트워크를 위한 협력 릴레이 통신은 공간 다이버시티를 통해 페이딩현상을 효율적으로 감소 시킬 수 있기 때문에 최근 활발히 연구되어 오고 있다. 본 논문에서 협력 릴레이 통신환경에서 decode-and-forward 기법을 적용한 balanced 전송 기법을 제안한다. 제안된 기법은 최고의 협력 다이버시티 이득을 얻기 위해 피드백 비트들을 선택한다. 제안된 기법은 기존의 기법과 비교하여 비트 오류 확률 성능을 증가시킬 수 있는 것을 모의 실험을 통해 증명하였다.