• 한국정보통신학회논문지
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• 제6권3호
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• pp.459-463
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• 2002

본 논문은 광섬유 증폭기에서 입력 펄스 열에 따른 gain recovery 특성을 고찰하였다. 1.3$\mu\textrm{m}$대역에서 증폭특성을 갖는 PDFA(Praseodymium-Doped Fiber Amplifier)의 WDM 적용시 short pulse 열을 인가한 경우 발생할 수 있는 이득 포화 및 복구의 시간적 한계를 이론적으로 해석하였다. 펄스열의 간격과 펌프 파워, 그리고 펄스 간격에 따른 이득 포화 및 복구 시간이 광 펄스의 증폭에 미치는 영향을 예측할 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 춘계종합학술대회
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• pp.505-508
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• 2002

본 논문은 광섬유 증폭기에서 입력 펄스 열에 따른 gain recovery 특성을 고찰하였다. 1.3$\mu\textrm{m}$ 대역에서 증폭 특성을 갖는 PDFA(Praseodymium-Doped Fiber Amplifier)의 WDM 적용 시 short pulse 열을 인가할 경우 발생할 수 있는 이득 포화 및 복구의 시간적 한계를 이론적으로 해석하였다. 펄스열의 간격과 펌프 파워, 그리고 펄스 간격에 따른 이득 포화 및 복구 시간이 광 펄스의 증폭에 미치는 영향을 예측할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.157-157
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• 2000

In the fuzzy control for the multi-variable system, it is difficult to obtain the fuzzy rule. Therefore, the parallel structure of the independent single input-single output fuzzy controller using a pairing between the input and output variable is applied to the multi-variable system. The concept of relative gain matrix is used to obtain the input-output pairs. However, among the input/output variables which are not paired the interactive effects should be taken into account. these mutual coupling of variables affect the control performance. Therefore, for the control system with a strong coupling property, the control performance is sometimes lowered. In this paper, the effect of mutual coupling of variables is considered by tile introduction of a simple compensator. This compensator adjusts the degree of coupling between variables using a neural network. In this proposed neuro-fuzzy controller, the Neural network which is realized by back-propagation algorithm, adjusts the mutual coupling weight between variables.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.144-146
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• 1999

This paper provides an analysis of the effect of input signals, such as acceleration power and generator shaft speed for improving Power System Stabilizer(PSS) efficiency. We consider a single machine and infinite bus system which is modeled by PSCAD/EMTDC. We choose an optimum stabilizer gain with respect to eigenvalue analysis and transient stability analysis to each input signal.

• 정보통신설비학회논문지
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• 제4권1호
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• pp.15-21
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• 2005

One of the core technology in WDM-PON system is a generation and modulation technique of the optical source in Optical Network Unit (ONU). In this paper, we propose a reflective semiconductor optical amplifier (RSOA) as a modulator in WDM-PON system. Its performance is analyzed by simulation and actual experimentation. Using RSOA in WDM-PON system as a modulator, it obtains higher gain compared to the conventional SOA due to the double pass gain effect. Furthermore RSOA can provide high gain with comparatively low input power. This is very helpful when we set up the actually system because using lower input power, it can reduce the load of the driving circuit which makes very economical module structure. Therefore, when RSOA is used as a modulator, not only it gives noise suppression effect, but also provides certain amount of gain as well. In addition, comparing with conventional SOA which gives fairly large insertion loss, RSOA can provides more important merits.

• 동력기계공학회지
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• 제3권1호
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• pp.50-54
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• 1999

In order to reject the steady-state tracking error, it is common to introduce integral compensators in servosystems for constant reference signals. However, if the mathematical model of the plant is exact and no disturbance input exists, the integral compensation is not necessary. From this point of view, a two-degree-of-freedom(2DOF) servosystem has been proposed, in which integral compensation is effective only when there is modeling error for disturbance input. The present paper considers the design problem of 2DOF servosystem incorporating an observer. It is shown that if a state feedback gain and a observer gain satisfy a condition, the integral effect does not appear when modeling error or disturbance input exists. This result means that the servosystem does not behave as a 2DOF servosystem.

• 대한전자공학회논문지
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• 제10권5호
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• pp.7-15
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• 1973

부귀환펄스선형증폭기에 단계전압과 방사능검출기에서 나오는 펄스와 같이 빠른 펄스를 인가하였을 경우의 이득 안정도에 관하여 해석하였고 실험하였다. 이들 빠른 입력전압이 부귀환증폭기에 인가되면 출력전압의 선형도와 안정도는 증폭기의 rise time의 수배가 경과하여야 부귀효과가 나타난다. 이 제한을 주리기 위하여는 부귀환증폭기의 rise time을 계측할려는 입력펄스의 폭보다 적도록 설계하여야 한다는 것을 표시하였다.

• 대한전기학회논문지
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• 제40권2호
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• pp.200-206
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• 1991

In this paper, an output feedback is used to reduce the effect of the vibration in the control of a flexible one-link robot arm. A PD control method with a time varying gain is proposed to improve the performance of the system in tip deflection and settling time for the step reference input. By making the change of feedback gain smoothly, th input torque can be made smooth. When there is a payload with unknown mass, an interpolation method which uses the inrehgrated value of the transient response of the hub angle is proposed for the estimation of teh payload mass. This method can be used when the reference input is known and we can get highly accurate estimate for the unknown payload. It is also demonstrated that flexible one-link arm can be controlled prettry accurately by an output feedback in a noisy environment without knowing the mass of the payload.

• 전기학회논문지
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• 제59권10호
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• pp.1809-1815
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• 2010

This paper presents an improved method for high-resolution rotor position estimation in the permanent magnet synchronous motor (PMSM) drives with low-resolution Hall-effect sensors. The proposed method adopts a gain-scheduled full-order speed observer. Since the quantized position signal, which is obtained from Hall-effect sensors, is basically used as the input of the observer, the sixth-order harmonics are essentially included in the estimated position. To eliminate the harmonic components, the quantized position is linearized by a linear extrapolation based on the estimated average speed and futhermore the speed-depentent observer gain scheduling strategy is developed. The observer gain is also scheduled by considering the motor acceleration to improve the dynamic performance according to the changes of the motor speed and load. Several experiments are performed for 800W PMSM drive and the results demonstrate the effectiveness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.179-182
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• 2003

A simulation on bootstrapping circuit has been performed by modelling a coaxial cable as a transmission line. It is shown that the bootstrapping circuit could be unstable due to the transmission line effect though an ideal amplifier is used. While the conventional bootstrapping circuit does not cancel the input capacitance of the input buffer, a new bootstrapping circuit that cancels input capacitance of the input buffer has been proposed. The proposed bootstrapping circuit consists of the input buffer of which gam is larger than 1 and a feedback resistor to control the loop gain. The proposed bootstrapping circuit has higher input impedance than that of the conventional circuit.