• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1999년도 PROCEEDINGS OF 99 INTERNATIONAL CONFERENCE OF THE KACG AND 6TH KOREA·JAPAN EMG SYMPOSIUM (ELECTRONIC MATERIALS GROWTH SYMPOSIUM), HANYANG UNIVERSITY, SEOUL, 06월 09일 JUNE 1999
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• pp.209-225
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• 1999

Detailed description of the crystal growth methods permitting one to obtain complicated shape crystals from the melt is given. The variable shaping technique provides the growth of crystals with a discrete altering cross-section configuration during crystallization. The dynamic local shaping technique enables one to grow items with a continuous alteration of the side surface profile by a preset program.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권1호
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• pp.111-119
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• 2013

This paper present stabilization control of fixed speed wind generator by using variable speed permanent magnet wind generator in a wind farm connected with multi-machine power system. A novel direct-current based d-q vector control technique of back to back converter integrated with Fuzzy Logic Controller for optimal control configuration is proposed, in which both active and reactive powers delivered to a power grid system are controlled effectively. Simulation analyses have been performed using PSCAD/EMTDC. Simulation results show that the proposed control scheme is very effective to enhance the voltage stability of the wind farm during fault condition.

• 한국결정성장학회지
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• 제9권4호
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• pp.417-423
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• 1999

Detailed description of the crystal growth methods permitting one to obtain complicated shape crystals from the melt is given. The variable shaping technique provides the growth of crystals with a discrete altering cross-section configuration during crystallization. The dynamic local shaping technique enables one to grow items with a continuous alteration of the side surface profile by a preset program.

• 전기학회논문지P
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• 제60권1호
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• pp.48-52
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• 2011

Over the years, traditionally, six-switch three-phase inverters have been widely utilized for variable speed alternating current motor drives. Recently, some efforts have been made on the application of four-switch three phase inverter for uninterruptible power supply and variable speed drives. This is due to some advantages of the four-switch three phase inverter over the conventional six-switch three-phase inverters such as reduced price due to reduction in number of switches, reduced switching losses, reduced number of interface circuits to supply logic signals for the switches, simpler control algorithms to generate logic signals, less chances of destroying the switches due to lesser interaction among switches, and less real-time computational burden. However such as slow di/dt and speed limitation, are the inherent characteristics and main drawbacks of the four-switch configuration. Those problems can be overcome in conjugation with Voltage-doublers which has additional advantage, such as unity power factor correction.

• 대한기계학회논문집B
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• 제33권11호
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• pp.886-893
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• 2009

To develop glass panel vacuum lift system for the post process in module line of FPD(Flat panel display) such as LCD and PDP, new vacuum adsorption parts of this system are proposed. These parts are composed of variable geometry configurations utilizing ceramic porous medium for variable size of glass panels. In order to design this device, detail understanding of flow phenomena in the flow path of vacuum adsorption system is essential. Thus, CFD analysis and designs are performed for several configurations in terms of pressure drop and balancing force at the adsorption side. From the result, new configuration is recommended for optimum design and manufacturing purpose.

• KIEAE Journal
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• 제4권2호
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• pp.11-18
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• 2004

Growing use of entire glass facades with metal frames are popularly witnessed in modern building practices and design competition as well. In spite of architectural aesthetics and view to outdoors, environmental issues still exist in that kind of buildings. One of the solutions for the problems might be the use of functional glasses such as a heat-resistant glass or various tinted glasses for the glass walls. This paper aims to provide performance data related to the impact of various transmittal materials of window systems on the light distribution. A series of computer simulation deals with the basic geometrical and optical design elements of a commonly used all-glass facades. Additionally an experimental configuration of the vertical window is proposed for better result of daylighting. A window system equipped with an inner-light shelf can improve the uniformity of natural light in a space by reducing the level of illumination near the window and redirecting light deeply into the space.

• 한국전자통신학회논문지
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• 제5권2호
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• pp.180-184
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• 2010

본 논문에서는 다중 채널 심장 전기도 주 증폭기의 중요한 부분인 필터를 설계하고 시뮬레이션을 통하여 성능을 분석하였다. 주 증폭기는 샘플/홀더, 가변 고역통과 필터, 노치 필터, 가변 저역통과 필터로 구성된다. 필터는 기존의 64 채널의 공간 분해능을 향상시키기 위하여 128채널을 고려하여 설계되었다.

• Structural Engineering and Mechanics
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• 제41권5호
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• pp.591-604
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• 2012

This paper provides an iteration approach for the solution of multiple notch problem, which is based on the complex variable boundary integral equation (CVBIE). The contours of notches are applied by some loadings. The source points are assumed on the boundary of individual notch and the displacements along the boundaries become unknowns to be investigated. After discretization of the BIE, many influence matrices are obtained. One does not need to assemble many influence matrices into a larger matrix. This will considerably reduce the work in the program. The displacements along the many boundaries can be obtained from an iteration. There is no limitation for the configuration of notches. Several numerical examples are provided to prove the efficiency of the suggested approach.

• 전기학회논문지
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• 제57권8호
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• pp.1464-1469
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• 2008

A CMOS Gm-C filter with variable cutoff frequency applicable for using in the direct conversion receiver is designed. The designed filter comprises the CMOS differential transconductors, and the gm of the transconductor is controlled by the bias voltage. This configuration can compensate variant of the cutoff frequency which could be generated by external noises, and also be used in multiband receiver. As a results of HSPICE simulation, the control range of the cutoff frequency is $1.5MHz{\sim}3.5MHz$ and the gain control range is $-2.8dB{\sim}2.6dB$. The layout of the designed 5th-order Elliptic low-pass filter is performed to fabricate a chip using $2.5V-0.25{\mu}m$ CMOS processing parameter.

• 전기학회논문지P
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• 제65권3호
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• pp.151-157
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• 2016

This paper proposes the variable wind generation system based on the direct torque control(DTC)for the interior permanent magnet synchronous generator. The proposed system can achieve the MPPT control without wind speed in addition to the speed and position sensorless control as well as the conventional current control method. The DTC has several advantages such as simply system configuration, ease of the flux weakening control and the sensorless control. The experimental results show the performance of the proposed wind generation system.