• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.571-575
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• 2001

A protection scheme for hybrid active power filters, which is combined shunt passive filter and small rated series active filter, is presented and analyzed in this paper. The proposed series active power filter operated as a high impedance 'k($\Omega$)' to the fundamental component when over current occurs in the power distribution system, and three control strategies are proposed in this paper. The first is the method by detecting the fundamental source current through the p-q theory, the second is the method by detecting the fundamental component of load current in Synchronous Reference Frame (SRF) and the third is the method by detecting the input voltage. When the over current occurs in the power distribution system, the proposed scheme protects the series active power filter without additional protection circuits. The validity of proposed protection scheme is investigated through experimental result for the prototype hybrid active power filter system.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.612-617
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• 2002

To provide beginner with the standard current information on the $\alhpa-\beta$ reference frame of nonlinear load, this paper has focused on the simulation works using MATLAB/SIMULINK in case of current source thyristor controlled rectifier The various $\alhpa-\beta$ components of current/power components are induced by the p-q theory, the results are represented waveforms and trajectories on the $\alhpa-\beta$ reference frame. The compensation effect according to each of the compensating reference components are described.

• Bulletin of the Society of Naval Architects of Korea
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• v.14 no.2
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• pp.1-9
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• 1977

Streamlines around a ship's hull can be calculated by using streamline tracing method replacing the ship section with distribution of singularity. The influence of frame lines on the stream surrounding a hull surface, however, can not be found. Jinnaka studied on streamlines for Lewis form by applying the slender body theory. The influence of frame lines on stream surrounding a hull surface is well found in Jinnaka's method. In this paper streamline calculation method for chine type has been developed by using conformal transformation and applying slender body theory as Jinnaka did. Three kinds of model-one of series 62 for chine type, V.L.C.C. and high speed craft built in Korea for Lewis form-were used for streamline calculation;

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.216-218
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• 2017

The imbalance at the 3-phase side at the railway power supply substation has been a well-known issue. Due to the difference in status of loads at each phase at any given moment, it is difficult to maintain the balance in the 2-phase side of the transformer. Consequently, the 3-phase side also presents a certain level of imbalance as well. A co-phase power supply was proposed as a solution. The real application of such system is gradually expanding, proving the effectiveness of the system. In this paper, the application of the single phase D-Q rotating frame theory was applied to the control of the co-phase power supply system. In addition, the power stack of the system was composed of MMC valves, which offers superior operational characteristics. The effectiveness of the system was verified with a real-time simulation, and the results are presented.

• International Journal of Advanced Culture Technology
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• v.12 no.1
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• pp.158-168
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• 2024

With Wenhai big data SaaS cloud platform.2.0, this study analyzed data of 135 news reports relating to Chinese city Chongqing from Yonhap News Agency and ten South Korean mainstream newspapers from May 1^st, 2018 to September 30^th, 2022. Under the framework of Frame Theory, this research conducted data mining and analysis on how Korean mainstream media shaped city image of Chongqing, what kind of city images were shaped from dimensions of politics, economy, society, culture & sports as well as tourism and whether they are consistent with those in Chinese media. At the last part, discussions and suggestions was made.

• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.114-132
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• 2011

We have proposed a new approach based on energy gradient concept for the study of flow instability and turbulent transition in parallel flows in our previous works. It was shown that the disturbance amplitude required for turbulent transition is inversely proportional to Re, which is in agreement with the experiments for imposed transverse disturbance. In present study, the energy gradient theory is extended to the generalized curved flows which have much application in turbomachinery and other fluid delivery devices. Within the frame of the new theory, basic theorems for flow instability in general cases are provided in details. Examples of applications of the theory are given from our previous studies which show comparison of the theory with available experimental data. It is shown that excellent agreement has been achieved for several configurations. Finally, various prediction methods for turbulent transition are reviewed and commented.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.408-410
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• 1992

An adaptive hybrid position/force controller for constrained manipulator with uncertain dynamic model parameters and environment stiffness is presented. In this paper, the compliance frame model is constructed by independent positions and forces to be controlled. The adaptive controller based on this compliance frame dynamic model is designed. Lyapunov theory is used for controller design and Stability analysis.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.2
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• pp.168-175
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• 1988

This paper describes a User guidance System aimed for user-friendly workstation guider that extracts Conceptual Structure from the input sentence by use of CE theory and performs Question Answering in Teletex Manual domain. It uses Frame typed knowledge base and CD recognizer as link procedure between CE structure and Frame controller.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.05a
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• pp.57-60
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• 2001

In this paper, we propose growing algorithm of wavelet neural network. It is growing algorithm that adds hidden nodes using wavelet frame which approximately supports orthogonality in wavelet neural network based on wavelet theory. The result of this processing can be reduced global error and progresses performance efficiency of wavelet neural network. We apply the proposed algorithm to approximation problem and evaluate effectiveness of proposed algorithm.

• Magazine of the Korea Concrete Institute
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• v.6 no.5
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• pp.183-192
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• 1994

Seismic safety of RC structure can be evaluated by numerical analysis considering randomness of earthquake motion and hysteretic behavior of reinforced concrete, which is more rational than determirustic analysis. In the safety assessment of aseismatic structures by the deterministic theory, it is not easy to consider th effects of random variables but the reliability theory and random vibration theory are useful to assess seismic safety with considering random effects. This study aims at the evaluation of sesmic damage and risk of the RC frame structure by stochastic response analysis of hysteretic system and then the calculation stages of the prob ability of failure are presented.