• International Journal of Control, Automation, and Systems
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• 제3권spc2호
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• pp.308-314
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• 2005

Transient stabilization with voltage regulation is investigated for a synchronous generator when the mechanical power is perturbed to any unknown value within its physical bounds so that the operating point of the system shifts to an unknown point. An adaptive excitation controller is designed based on the backstepping method with tuning functions. It will be shown that the adaptive control law proposed can achieve the convergence of the system states to the new equilibrium point in correspondence with the real value of the unknown mechanical power and the regulation of the terminal voltage to the required value. Simulation results are given to demonstrate the effectiveness of the proposed controller for the transient stabilization and voltage regulation.

• 사상체질의학회지
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• 제10권1호
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• pp.55-63
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• 1998

The symptoms that have same pathologic pattern written in the chapter of Soyangin's general pathology of the book 'Dongyi Soose Bowon' can give us a key to the Dr.Lee Je-Ma's point of view about the constitutional pathophysiology. As the result, Dr. Lee called the person who has yang-hyperactivity/yin-hypoactivity as So-Yang-In. And the Soyangin has two basic pathologic pathway ; excess of Yang-hyperactivity/excess of Yin-hypoactivity. Each pathologic pathway has variatons though, the pathologic pattern results in above two type. Excess Yin-hypoactivity has three variations of pathologic pattern. 1. smaller excess of Yin-hypoactivity with the normal range of Yang-hyperactivity 2. larger excess Yin-hypoactivity with the excitation of Yang-hyperactivity by the extrinsic factor 3. smaller excess Yin-hypoactivity with the loss of Yang-hyperactivity. And excess Yang-hyperactivity also has three variations. In my point of view, CVA, Hematemesis, Vommiting, Abdominal Pain, Gastric Dyscomfort has No.3 type and Asthmatic condition, Dysentery, Edema has No.1 type.

• Journal of Power Electronics
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• 제14권4호
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• pp.796-805
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• 2014

A digital controller with a low-power approach for point-of-load synchronous buck converters is discussed and compared with its analog counterpart to confirm its feasibility for system integration. The tri-mode digital controller IC in $0.35{\mu}m$ CMOS process is presented to demonstrate solutions that include a PID, quarter PID, and robust RST compensators. These compensators address the steady-state, stand-by, and transient modes according to the system operating point. An idle-tone free condition for ${\Sigma}-{\Delta}$ DPWM reduces the inherent tone noise under DC-excitation. Compared with that of the traditional approach, this condition generates a quasi-pure modulation signal. Experimental results verify the closed-loop performances and confirm the power-saving mechanism of the proposed controller.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.516-523
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• 1998

Radiation efficiency of a cylindrical shell whose surface vibrates under harmonic distribution is investigated by theoretical solutions and Boundary Element Method. The vibration modes of a cylindrical shell is determined from experiment and is compared with the result of Finite Element Method. Harmonic vibration response of the cylindrical shell under the point excitation and the radiation phenomena from its response is analyzed by Finite Element Method and Boundary Element Method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.413-418
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• 2001

The moire phenomena, which are induced by mask vibration due to the excitation of speakers, degrades the color purity of CRT. So it is important to eliminate this phenomena to obtain a good CRT design. In this study we analyze the mask vibration by experiment as well as finite element method. To obtain the finite element solutions efficiently, an equivalent model was employed. The experimental and analysis results show reasonable agreements. An enhanced design configuration of mask welding points are suggested through this study.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 춘계학술대회 논문집
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• pp.85-90
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• 1996

In the word, there is varied types of vibration, and these affect the mechanical industry. In this paper is plates with two parallel sides fixed. Electronic speckle pattern interferometry (ESPI) is one of the optical nondestructive testing technique. By using the ESPI, vibration modes for excitation point, a/b(ratio of longuitudinal and lateral length), and kind of specimen are measured and compared qualitatively with theoritical analysis that Warburton proposed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1055-1060
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• 2001

Springing phenomena of ships is introduced with its concept, research history and approach methodology. Being a hydroelasticity problem, non-linear vibration and stochastic process, springing was formulated and modeled in vibration point of view separating hydrodynamic force into system properties and excitation force. Both RAO and response spectrum as well as wave spectrum were presented as a case study of springing analysis for a flexible vessel with wide breadth. The effect of advance speed, heading angle and loading condition were investigated as parametric study. The results and observations showed availability of analysis for the prediction of the ship springing behavior.

• 전기학회논문지
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• 제61권12호
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• pp.1864-1871
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• 2012

This paper proposes the hybrid proportional integral(HBPI) controller for maximum power point tracking(MPPT) control of photovoltaic system. The output characteristics of the solar cell are a nonlinear and affected by a temperature, the solar radiation and influence of a shadow. The MPPT control is a very important technique in order to increase an output and efficiency of the photovoltaic system. The conventional constant voltage(CV), perturbation and observation(PO) and incremental conductance(IC) are the method which finding maximum power point(MPP) by the continued self-excitation vibration, and uses the fixed step size. If the fixed step size is a large, the tracking speed of maximum power point is faster, but the tracking accuracy in the steady state is decreased. On the contrary, when the fixed step size is a small, the tracking accuracy is increased and the tracking speed is slower. Therefore, in order to solve these problems, this paper proposes HBPI controller that is adjusted gain of conventional PI control using fuzzy control, and the maximum power point tracks using this controller. The validity of the controller proposed in this paper proves through the results of the comparisons.

• 한국음향학회지
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• 제14권4호
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• pp.38-45
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• 1995

본 논문에서는 CELP (Code Excited Linear Prediction) 부호화기의 장구간 예측단에 MBE(Multi-Band Excitation) 방법을 도입하여 4.8kbps 이하의 낮은 전송률에서 성능을 향상시키는 방법을 제안한다. 제안한 방법에서는 기존의 CELP 방법으로 장구간 예측을 한 후에도 여전히 남아 있는 주기적 성분들을 다시 한번 다중대역(multiband)으로 장구간 예측을 한다. 이때 전 스펙트럼을 기본 주파수의 하모닉 간격으로 대역 분할하고, 주기적 다중대역 여기 신호는 각 대역 내의 하모닉들에서 여기 신호 스펙트럼과 근사한 크기를 갖는 정현파 (sine wave)의 합으로 표현함으로써 실제 여기 신호의 특성을 잘 반영하도록 한다. 제안된 방법의 성능 평가를 위해서 4.8 kbps의 전송률에서 컴퓨터 모의 실험을 하였다. 음질 평가의 비교 기준 대상으로 4.8 kbps DoD CELP와 4.4 kbps IMBE를 선정하여 주관적인 음질 평가를 실시한 결과 4.8 kbps DoD CELP보다 우수하였고, 4.4 kbps IMBE와는 비슷하였다.

• 한국음향학회지
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• 제14권3호
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• pp.5-13
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• 1995

본 논문에서는 새로운 실린더 운동방정식을 유도하고, 실린더 좌표의 각 방향에 대해 가정해로써 선형방정식을 구하였다. 또한, 점 자극을 가정하여 어드미턴스를 구하였고, 그 결과를 그림으로 나타내었다. 임피던스를 통해서 자유파수를 구하였고, 그 결과를 그림으로 나타내었으며, 이러한 계산 결과를 통하여 실린더에서 발생하는 진동 해석의 가능성을 보였다.