• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.6
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• pp.220-229
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• 1985

This paper proposes a new optimal unit commitment algorithm for the rational operation of electric power systems. Especially, the algorithm is improved by considering transmission line capacity limits and load forecasting uncertainty with the consideration of the participation factors of each units, so that the method becomes more reliable and flexible one. The transmission losses are considered by using updated penalty factors obtained from the constant matrixes of the fast decoupled load flow method, the system loads are distributed at each buses, and the several necessary operational constraints are also considered for the purpose of presenting a more practicable scheme. Finally, the effectiveness of the proposed algorithm has been demonstrated by applying to the 23-bus model system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.131-138
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• 1996

In this paper, we consider an iterative learning control system(ILCS) consisting of an iterative learning controller, a feedback controller and a controlled plant in the frequency domain. At first, we review the convergence of ILCS. And we give some design guidelines of the ILCS using a nominal model of the plant. Then we present the structured and the unstructured uncertainty bound which guarantees the convergence of the designed iterative learning controller. In particular, we analyze the relationship between the convergence and the magnitude and phase uncertainties. In order to show the usefulness of the proposed analysis and design guidelines, we present some simulation examples. (author). 13 refs., 5 figs.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.8
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• pp.972-979
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• 1999

QFT(Quantitative Feedback Theory) is a very practical design technique that emphasizes the use of feedback for achieving the desired system performance tolerances in despite of plant uncertainty and disturbance. The fundamental concept of QFT is a loop shaping procedure that a suitable controller can be found by shaping a nominal loop transfer function. The loop shaping synthesis involves the identification of a structure and the specialization of parameter optimization of a desired system. This paper presents an improved loop shaping approach of QFT with model validation using GA(Genetic Algorithm). The method presented in this paper removes the problems of iterative operation, transformation error, and model validation in the conventional methods without consideration of frequency domain.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2020-2021
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• 2003

Korea Research Institute of Standards and Science (KRISS) has developed a Web-based, remote, Internet calibration system to calibrate the Fluke 5700A/5720A calibrator using a transportable standard: specifically, multifunction transfer standard 4950. Although the uncertainty for the Internet calibration is up to two times larger than that using conventional manual calibration, it has many advantages: no need to transport the customer equipment, a reduction in the calibration service time, a directly enforced traceability to the national standards, convenience, and ease of use for the customers.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2248-2250
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• 2003

This paper Backstepping design with Sliding Mode Control for AC Servo Systems. The robustness of sliding mode control can be used for backstepping technique to solve the uncertainty problem. A scalar design using Lyapunov function is developed for high-order systems. The result can be easily extended to non-linear system and used with many other sliding mode control results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.137-144
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• 2006

This paper proposes the design of a robust controller based on disturbance observer which is strong to variation of system parameters, uncertainty of models or external disturbance. The controller consists of a mode based compensator and a feedback controller based on two-loop structure. The compensator in the internal-loop removes internal and external disturbances and a feedback controller in the external loop achieves performance along with given specifications. As a result, it shows that the proposed robust controller can stabilize a system against disturbance and improve controlling performance.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.3
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• pp.204-209
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• 2016

It is difficult to establish accurate modeling of PV power system because of various uncertainty. However, it is important work to modeling of PV for fault diagnosis. This paper proposes modeling and fault diagnosis method using correlation analysis and ELM(Extreme Learning Machine). Rather than using total data, we select optimal time interval with higher corelation between PV power and solar irradiation. Also, we use average value during 60 minute to avoid rapid variation of PV power. To show the effectiveness of the proposed method, we performed various experiments by dataset.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1644-1645
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• 2007

This paper proposes an adaptive sliding mode control method for trajectory tracking of nonholonomic mobile robots with model uncertainties and external disturbances. The kinematic model represented by polar coordinates are considered to design a robust control system. Wavelet neural networks (WNNs) are employed to approximate arbitrary model uncertainties in dynamics of the mobile robot. From the Lyapunov stability theory, we derive tuning algorithms for all weights of WNNs and prove that all signals of an adaptive closed-loop system are uniformly ultimately bounded.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.537-538
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• 2005

A way of measuring an efficiency of organic light-emitting diodes are studied. The efficiency is obtained from the current-voltage-luminance characteristics of the devices. Basically, number of charge carriers are obtained from the current-voltage characteristics, and the number of photons are obtained from the current of Si-photodetector. The organic light-emitting diodes are assumed as a lambertian light source and a program is made for calculating the efficiency. A device structure of ITO/TPD/$Alq_3$/Al is manufactured using thermal-vapor evaporation. This device is set into a measuring system and measured the efficiency. The efficiencies are measured using the lab-made program and commercially available equipments. The obtained values are similar to each other within 10% uncertainty.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1324-1326
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• 2005

A high precision transformer bridge system for comparison of primary capacitance standards at low frequencies was developed. Its main transformer was constructed by special winding techniques and has the inphase and quadrature error of $0.073{\times}10^{-6}$ and $0.14{\times}10^{-6}$ at 1592 Hz($\omega=10^4$) respectively. But the measurement uncertainty of this bridge system can be achieved $0.03{\times}10^{-6}$ by using some substitution method.