• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.91-97
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• 2007

This paper presents a pitch angle controller of a grid-connected wind turbine system for extracting maximum power from wind and implements a modeling and simulation of the wind turbine system on MATLAB/Simulink. It discusses the maximum power control algorithm for the wind turbine and presents, in a graphical form, the relationship of wind turbine output, rotor speed, and power coefficient with wind speed when the wind turbine is operated under the maximum power control algorithm. The objective of pitch angle control is to extract maximum power from wind and is achieved by regulating the blade pitch angle during above-rated wind speeds in order to bypass excessive energy in the wind. Case studies demonstrate that the pitch angle control is carried out to achieve maximum power extraction during above-rated wind speeds and effectiveness of the proposed controller would be satisfactory.

• Journal of the Korean Society of Safety
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• v.23 no.4
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• pp.72-78
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• 2008

In any form of construction work, it is essential that accidents be prevented at every stage from foundation preparation to build completion. For this, it is necessary to use models that can assess risk and provide instruction for safe work processes so that the risk of accidents is reduced. Currently, however, very few models can perform these tasks. In this paper, we presents a model that assesses risk quantitatively by analyzing risk factors involved in stage of construction such as foundation work, erection work, structural work, equipment work, finishing work and etc work. The model performs assessment based on examples of accidents and by investing actual conditions during construction. In addition, we presents in this paper a safety management system was developed to assess risk during construction and to effectively train laborers.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.378-383
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• 2012

This paper presents the implementation of an automatic road sign recognizer for an intelligent transport system. In this system, lists of road signs are processed with actions such as line segmentation, single sign segmentation, and storing an artificial sign in the database. The process of taking the video stream and extracting the road sign and storing in the database is called the road sign recognition. This paper presents a study on recognizing traffic sign patterns using a segmentation technique for the efficiency and the speed of the system. The image is converted from one scale to another scale such as RGB to grayscale or grayscale to binary. The images are pre-processed with several image processing techniques, such as threshold techniques, Gaussian filters, Canny edge detection, and the contour technique.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.1
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• pp.13-21
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• 2004

In the design of superconducting cable systems, quench analysis have to be advanced for applying to a real systems. It is necessary to calculate the current, voltage and resistance during the quench. Simulation program named EMTDC was used to analyze the quench state. Normal zone evaluation and quench development with EMTDC are one of the major features of quench analysis. This paper presents the two kinds of quench control models which are the Switch Control Type and the Fortran Control Type. In case of the quench developing area, the simplicity cable model consist of resistance, inductance and capacitance. The impedance of the pipe type superconducting cable is calculated by numerical analysis method. The resistance and inductance increased during quench. However the variation have an effect on the fault current. The voltage was also developed by resistance and inductance. This paper presents the relationship between the current. voltage, resistance and inductance during quench.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.495-497
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• 2000

The KEPCO is developing the load forecasting sysetm using land use simulation method and distribution planning system. Distribution planning needs the data of presents loads, forecasted loads sub-statin, and distribution lines. Using the data, determine the sub-station and feeder lines according to the load forecasting data. This paper presents the method of formulation processfor the long term load forecasting and optimal distribution planning and optimal distribution planning. And describes the case study of long term distribution planning of Kwangju city accord to the newly applied method.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.745-747
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• 2005

After restructuring electricity industry, national long term electricity plans moved to "Basic plan of electricity supply and demand" from "Long term power development plan". The main point is a change of path from plan of power development at national level to plan of electricity supply and demand at company level. A proposal by generation company is surveyed and reflected to the basic plan of electricity supply and demand. The second plan shows over 40% reserves in result of the proposals. It is the time to evaluating the proposal which covers market function in the basic plan of electricity supply and demand at the stage of market change. This research presents the need of evaluation of proposals and the methods of evaluation. Also it presents the alternative planning procedure to reflecting the evaluation methods.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.55-57
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• 2005

This paper presents the development and performance of a power conditioning system (PCS) for application to a 100kw Molten Carbonate Fuel Cell. (MCFC) generation system. The MCFC generation system is a part of a four year government funded research project that began in 2001. This paper presents the results of operation connected to an actual fuel cell stack at a field demonstration site. and this paper shows various tests and performance verification of the 100kW PCS using a simulated DC source.

• Journal of Korean Library and Information Science Society
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• v.36 no.2
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• pp.141-163
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• 2005

Today. the value of the references comes to be high and the reference database construction is increasing. But. the descriptive regulations of the reference which it presents from scholarly journals different with each other. Also, the researchers probably does not recognize a descriptive regulations of reference. It is likely that the effective construction of reference database is very difficult. So, the purpose of this study analyzes the differences of a descriptive regulations for reference and presents the plan for standardization of a descriptive regulations.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.169-170
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• 2012

This paper presents implementation of digital phase controller for thyristor by using FPGA (Field Programmable Gate Array) in HVDC system. Implementation of digital HVDC system is possible by using superior digital simulator such as RTDS (Real Time Digital Simulator). But thyristor phase controller is typically implemented by analog circuit, because it is difficult to implement the phase controller with low operating speed of RTDS. To guarantee high control performance, phase controller needs fast operating speed. This paper presents FPGA based digital phase controller to obtain high speed and high performance. The entire digital simulation of the HVDC system is also implemented by interfacing between FPGA based phase controller and RTDS. Proposed digital HVDC simulator is verified through RTDS simulation.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.472-476
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• 2003

A real train load fluctuates along the track because of complicated movements(Bouncing, Rolling, Pitching and Yawing) and rail conditions. This research has for its object in development of a numerical train load model including fluctuation characteristics of lateral forces. It is based on Klingel movement theory of a wheelset on straight track. it presents a propriety of application by comparison between a 3D-Numerical analysis result using this train load model and a measured data. And this paper presents further study subject to improve a method about the train load modeling.