• Journal of Korean Library and Information Science Society
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• v.36 no.3
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• pp.233-256
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• 2005

This study is arguing about the development of professionalism of children's librarians. For this, I investigated the conditions of operation in the course of library and information science and continuing education related to the training of children's librarians. Furthermore, I analyzed their problems. After this, I suggested the methods for the development of professionalism of children's librarians.

• Journal of Korean Library and Information Science Society
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• v.31 no.2
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• pp.223-251
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• 2000

The purpose of this study is to analyze the public library movement developed from Liberation to the Korean War and to identify the causes and the progress of the movement in the context of library history in Korea. For this, the circumstances in the Korean library world and the process of the public library movement from 1945 to 1950 are reviewed. Finally the result and the limit of the movement are evaluated as well.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.144-146
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• 2004

This paper presents experimental operation with utility invertactive 3kW photovoltaic generation system. And that describe configuration of utility interactive photovoltaic system which power supply for Demonstration experiment. The status of photovoltaic generation system comp-onents and interconnection and safety equipment will be summarized. This paper discusses property operation state which system endure division of power for demonstration experiment.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.618-620
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• 2008

본 논문에서는 대기 오염 물질의 방출이 적고, 소음이 적은 환경 친화적인 Ni-MH전지를 독립형 태양광 가로등시스템에 적용하였으며 충방전제어기를 구성하여 출력특성을 고찰하였다. 출력특성을 고찰한 결과 충전 및 방전이 원활히 진행됨을 알 수 있었다. 그러나 충전시 정전압 충전방식을 사용하였고 태양 전지 출력측에 MPPT제어가 이루어 지지 않은 탓으로 태양전지 이용률이 떨어지며 화창한 날 태양전지의 등가 발전시간은 약 6시간에서 7시간 정도 나오지만 축전지는 오전 중에 충전이 완료되고 오후발전량은 모두 버리게 됨을 알 수 있었다.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1296-1299
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• 2001

In this paper, a simple, novel approach is proposed for a variable hysterisis band current controller which uses feedback techniques to achieve constant switching frequency with good dynamic response. The simulation result shows constant switching frequency and consequenctly the load current ripple decrease.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1206-1208
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• 2001

Direct torque control(DTC) of AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement. DTC is also very simple in its implementation because it needs only two hysteresis comparators and switching vector table for both flux and torque control. The amplitude of hysteresis band greatly influences on the drive performance such as flux and torque ripple, switching frequency and current harmonics. Therefore, authors analysis flux and torque hysteresis bands is suggested considering switching frequency and harmonic distortion of currents.

• Korean Journal of Human Ecology
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• v.4 no.1
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• pp.93-107
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• 2001

The purpose of this study was examine the health and food intakes of industrial workers who worked day and night. The questionnaire asked them about their health, stress, knowledge of nutrition, food habits, food intakes and frequency. The night-time workers had a stomachache compaired with day-time workers. Male day-time workers were more prone to stress than night-time workers in the area of job. In the areas of nutritional knowledge and food habits, there were no significant differences between day-and night-time workers for both male and female. Intakes of rice, bread, noddle, meat, fish. beans, vegetables in night-time workers were less than day-time workers. Also the male night-time workers consumed more milk and carbonated drinks than the day-time workers. The night-time workers were worse than the day-time workers and the female night-time workers were the worst. Considering the above results, the night-time workers should correct their food habits and have a well-balanced diet.

• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.89-96
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• 2004

PV system is easy to operate and maintain than the other power generating system since it generally contains no moving parts, operates silently and requires very little maintenance. A solar cell generates DC power from sunlight whose power is different at any instance according to condition of irradiation and temperature variables. In order to improve the system utility factor and efficiency of energy conversion, it is desirable to operate the PV system at maximum power point of solar cell under different condition This paper describes the experimental results of the PV system contain solar modules and a DC-DC converter(boost type chopper) using fuzzy controller. The experimental results show that the PV system always operates at maximum power point of solar cells having stabilized output voltage waveform with relatively small ripple component.

• Journal of Korean Academy of Nursing
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• v.31 no.6
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• pp.1109-1118
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• 2001

The purpose of this study was to analyze the appraising frame and the accreditation system of universities in both Korea and the United Sates, as well as developing a standard plan to appraise 4 year nursing education institutions in Korea. Research design of this study was descriptive comparative research. The results of the research can be divided into six fields, educational purposes, educational courses, students, faculty, facility .equipments and administration.finance in Korea. Then the results were further categorized into seven fields : mission and governance, faculty, students, curriculum and instruction, resources, educational effectiveness and integrity. Thus Korean appraising frames were suggested to have eight fields of standard. The fields are philosophy and purposes of educational institution, educational courses and instruction, students, faculty, facility .equipments, adminstration.finance, educational effectiveness and integrity.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.544-548
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• 1999

Using Observer, on the sensorless vector control system is a novel techniques for modern induction motor control. In this paper, a speed estimation algorithm of an induction motor using an extended kalman filter was proposed. Extended kalman filter can solve the problem, that have steady state error of estimated speed in flux and slip estimation method. The extended Kalman filter is employed to identify the speed of an induction motor and rotor flux based on the measured quantities such as stator current and DC link voltage. In order to confirming above proposal, computer simulation carried out using Matlab Simulink and show the effectiveness of the control drives for induction motor speed estimation.