• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1769-1773
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• 1996

The remaining life of generator stator winding has been the controversial issue amomg many experts in this area. The report from Japan claims that they can predict the remaining life of generator winding, while the North American has the negative opinion about it. This study aimed at verifying the validity of both Japanese criteria and North American argument on evaluation of generator winding insulation. Non destructive and destructive tests were performed on two hydro-generators. The test results showed that the trend analysis of stator winding insulation was the better option.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.309-314
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• 2004

The exhaust gas emission from marine diesel engines is one of the major environmental issues. The authors focus the use of photovoltaic energy for the electric power system on marine ships. This paper proposes an operation method of a photovoltaic/diesel hybrid generating system for a small ship in consideration of the fluctuating photovoltaic power due to solar radiation. The aim of the proposed operation method is to minimize the fuel consumption and storage capacity of the battery. The validity of the proposed control method is shown by the numerical simulation based on the experimental data of the photovoltaic system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.7 no.1
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• pp.31-39
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• 1999

Through the use of well-designed measures of ability and aptitude, good selection can reduce training wastage, reduce the risk of accidents and increase the operational effectiveness of the successful trainees. Many countries in the world, they take various kind of aptitude test. Especially in Sweden, not like the other countries, they attach importance to interview test. As a result, they can reduce training wastage and accidents. In case of ROKAF, they take many kind of aptitude test, but it is not directly effective to the selection system. They take the several aptitude test in civil aviation in Korea, especially they attach importance to personality test. For the validity and accuracy of the aptitude test, until training pilot become professional pilot, we need a comparison analysis for initial aptitude test through the continuous observation. For theses process, we need a department with special person and development of testing system.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.322-327
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• 1999

In most railway vehicle applications, a single phase AC/DC converter is used greatly and is essential equipment for Korea High Speed Train. A diode bridge rectifier and a phase-controlled thyristor bridge rectifier generate harmonics in power system. Nowadays, power factor and harmonics become major issue in electrical equipment for railway vehicle. Many researchers have been trying to improve the power factor and ac-side harmonics. Therefore the PWM converter is used to operate at unity Power factor and to reduce ac-side current harmonics. This paper describes the circuit for AC/DC PWM converter of Korea High Speed Train and proposes control algorithm to realize the sinusolidal input current waveform and the effective unity power factor. The validity of the proposed control method is verified through the experimental result.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.8
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• pp.720-725
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• 2001

Derivation of TSK fuzzy model from nonlinear differential equation is fundamental issue in the field of theoretical fuzzy control. The method which does not yield affine local differential equations at off-equilibrium points is proposed in this paper. A prototype TSK fuzzy model which has triangular membership functions for linguistic terms of the antecedent part is derived systematically. And then GA is used to modify the membership functions optimally. Simulation results show the validity of the proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.401-406
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• 2013

The mobile robot is one of the widely-used systems in service industry. We propose a gain-scheduling feedback controller for the tracking control of the mobile robot. The benefit of our proposed controller is that it avoids the singularity issue occurs with the controllers suggested in [4], [10]. Moreover, we show the stability analysis of the controlled system via a Lyapunov stability approach such that the exponential convergence of tracking error to zero is analytically provided. The simulation results show the validity of the proposed controller and improved control performance over the conventional controller.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.554-560
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• 2011

Single-frequency induction heating equipment caused by a hardening heat treatment process of the double investment in the issue and allow the heat treatment process in order to shorten the time from one process to work simultaneously on two kinds of processes that allow Simultaneous Dual Frequency(SDF) drive scheme technology are described. In this paper, we propose a dual way to drive a simultaneous dual-frequency drive scheme has been implemented. Through simulations and experiments, we can obtain the validity of the proposed inverter for dual-frequency control and power control.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2946-2951
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• 2008

Combustion instability is a major issue in design of gas turbine combustors for efficient operation with low emissions. Combustion instability is induced by the interaction of the unsteady heat release of the combustion process and the change in the acoustic pressure in the combustion chamber. In an effort to develop a technique to predict self-excited combustion instability of gas turbine combustors, a new stability analysis method based on the transfer matrix method is developed. The method views the combustion system as a one-dimensional acoustic system with a side branch and describes the heat source as the input to the system. This approach makes it possible to use the advantages of not only the transfer matrix method but also well-established classic control theories. The approach is applied to a simple gas turbine combustion system to demonstrate the validity and effectiveness of the approach.

• Journal of the Korea Safety Management & Science
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• v.9 no.5
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• pp.87-95
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• 2007

Logistics creates a boom in accordance with the recent new technique's development along with the recent RFID/USN of ubiquitous computing technique. The wave of 4PL(Fourth Party Logistics) that added the strategic consulting based on new IT techniques to logistics outsourcing through existing 3PL service with is a great issue. Moreover, the customer enterprises which contained manufacturers and distributors need the one stop service, therefore a method for effectively dealing with global logistics' environment changes is needed. Above all, a development of the 4PL system with RFID is very urgent. We developed the RFID u-4PL system progressed more than the present system, in which we applied many international standards. Finally, we constructed the web service based on Web 2.0 because of important condition of 4PL.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.128-133
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• 2009

Brain drain of scientists and technologists to the United States from other countries is a phenomenal issue due to the potential developmental impacts it could have on sending countries. Immigration policies undoubtedly play the major part to shape the human resource outcomes. There has been a common sense explanation to the brain drain trend, which states that the lower English language requirements in the scientific and technology jobs compared to other high skill brain drain jobs offer immigrants more favorable employment opportunities. These and other language related variables are used with standard human capital model variables to assess the validity of the common sense proposition.