• Journal of the Korean housing association
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• v.15 no.5
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• pp.77-84
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• 2004

The mock-ups of ventilation system, which has been widely adopted for the bathroom with the area of 100 $m^2$ apartment housing, were established and tested to design mechanical ventilation for apartment housing bathroom where air supply exhaust are relatively important. These ventilation mock-ups were capable of controlling intake and exhaust, which has the size of supply openings as 40cm${\times}$1cm, 40cm${\times}$3cm, 40cm${\times}$5cm. They were established at five locations, spaced 40cm from each other at a height of 25cm from the floor. The exhaust fans were located at four corners and center of the ceiling. The results this ventilation effect measurement by different condition are showing that when the size of air supply is bigger and the location is lower, the effect of ventilation was relatively higher. In addition, as the distance between exhaust fan and air supply was farther, the ventilation effect were getting highly efficient.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.3
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• pp.116-124
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• 2002

Design and analysis of disturbance observer-based deadbeat control fur single-phase inverter applications are comprehensively presented in this paper. Load current can be estimated by disturbance observer, which is basically structured with the first order equation in this case and is regarded as a relatively simple method in comparison with conventional full-order Luenberger observer. Also, an inherent one-step delay problem appeared in the deadbeat control method is overcome by a simple prediction technique proposed. Output voltage dip is reduced by the feedforward control with the change rate of the estimated load current involved in the deadbeat current control loop. The proposed algorithms are verified by the respective simulation and experiment results.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.2 no.2
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• pp.59-63
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• 1988

In a fixed AC power source the PWM techniques were used to vary the voltage and the fundamental frequency. The conventional PWM techniques due to the problem of commutation number and filter size have been studied the PWM output waveforms which applied the motor drive. However in this paper, the carrier frequency with sinusoidal PWM waveform is modulated from 10(KHz) to 45(KHz) using termination devices with high - speed switching capacity and applying LPF(Low Pass Filter) with small capacity to output of inverter and the PAM(Pulse Amplitude Modulation)is obtained. Considering the property of the speed and the control, the sinusoidal PWM control circuit was composed of the microprocessor and analog circuit. In experment result, the system properties are study on the sinusoidal voltage waveform with modulation index changing from 0.6 to 1.0.

• Journal of the Korean housing association
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• v.12 no.3
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• pp.141-148
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• 2001

To design mechanical ventilation for bathroom of apartment houses where air supply and exhaust are taken into consideration, mock-ups of ventilation systems, widely used in bathroom of apartment houses with an area of 100$\textrm{m}^2$, were made and installed in a laboratory. These ventilation mock-ups were available for control of air supply and exhaust, and the sizes of supply openings were 40cm${\times}$1cm, 40cm${\times}$3cm, and 40cm${\times}$5cm. They were installed at five positions, spaced 45cm at a height of 5cm from the floor. The exhaust fan was designed for its operating voltage to be set to five steps(100V, 130V, 150V, 180V and 220V) in order to control its air flow rates. When the size and position of each supply opening were changed with the wind velocity of the exhaust fan set to the step 5, the ventilation rates were measured and analyzed by the concentration decay method of tracer gas method, in order to present an efficient mechanical ventilation system. The results of the study revealed that the ventilations rates would increase in the presence of supply openings, compared to the absence of supply openings, and that the larger the size of the supply opening, the more the ventilation rates. Therefore, it was found necessary to take air supply into consideration.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.37-38
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• 2012

무정전전원장치(UPS: Uninterruptible Power Supply)는 정전 등의 사고가 발생할 때 양질의 전원을 부하에 공급하는 장치이다. 무정전전원장치의 구성은 크게 역률개선회로, 인버터, battery charger, battery discharger부로 크게 4개로 나눌 수 있다. 그 중 정전 등의 사고발생 시 battery에 충전되었던 에너지를 인버터 부로 공급하여야하며 이를 담당하는 부분이 battery discharger부이다. battery의 전압은 비교적 낮은 전압이며 인버터의 입력에 필요한 전압은 비교적 큰 전압이기 때문에 승압형 컨버터가 필요하게 된다. 본 논문에서는 UPS battery discharger용 3KW급 LLC 공진형 컨버터를 설계하고 실험 검증하였다.

• Journal of Engineering Education Research
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• v.21 no.6
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• pp.108-117
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• 2018

Given the substantial industrial and economic contributions of university start-ups, a growing number of studies have adopted the ecosystem perspectives to systematically explain creating start-ups in universities. Despite the huge theoretical potential, few studies have analyzed the complex, complimentary interactions of the core components in the university entrepreneurship ecosystems (UEEs). Addressing the limitation, this research not only discusses the role of the core ecosystem components, such as patents, entrepreneurship education, and student entrepreneurship clubs, but also analyzes their discrete and complimentary effects on the productivity of UEEs. Based on a national survey of universities, this study shows that all the core components have a positive effect on the ecosystem productivity. More importantly, this study investigated the complimentary relationships among components and tested the moderation effects of both the entrepreneurship education and the student clubs on the relationship between the patents and the productivity of UEEs. The analysis results show that the student clubs intensify the patents' positive effect on the productivity of UEEs. The research results could provide the crucial policy insights for the successful design of UEEs.

• Journal of dental hygiene science
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• v.17 no.4
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• pp.323-332
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• 2017

This study aimed to investigate the factors influencing the decision on whether to receive regular oral check-ups among the national health insurance beneficiaries with income and aged over 20 years in Korea. This was a cross-sectional study, using the data from the 2014 6th Korea National Health and Nutrition Examination Survey (KNHANES VI-2), conducted by the Korea Centers for Disease Control and Prevention. The final sample included 2,843 subjects who participated in the health examination survey and oral check-ups. The IBM SPSS Statistics ver. 20.0 was used for the statistical analysis, based on the complex sampling design. The Rao-Scott chi-square test was used to verify the difference in the distribution of independent variables with regard to oral check-ups. The binary logistic regression analysis was used to determine the influencing factors. The ratio of beneficiaries who received oral check-ups was less than half of those who received medical examinations. The Rao-Scott chi-square test, revealed significant differences in the age group (p<0.05) of the predisposing factors, toothache within a year (p<0.001), untreated dental caries (p<0.001) of the need factors, personal income level (p<0.001), educational level (p<0.001), type of medical insurance (p<0.001), and private health insurance (p<0.01) of the enabling factors. In the binary logistic regression analysis, factors influencing oral check-ups were age group, personal income level, educational level, toothache within a year, and untreated dental caries. These findings show a variety of factors influencing the utilization of regular oral check-ups.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.5
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• pp.152-158
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• 1996

A novel resonant pulse control technique which generates high-quality sinusoidal output voltage from a resonant dc link inverter is presented for UPS applicatons. The proposed control technique limits resonant voltae overshoot without any passive or active clamp circuit, resulting in resonant pulses iwth uniform amplitude and high efficiency. The output voltage is controlled by the third order contorller iwth an inner loop of th efilter inductor current and the feedforward controller. Analysis and design of the proposed control technique are illustrated and verified on a 5kVA experimental unit.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.23-24
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• 2017

본 논문은 무정전전원장치의 전압품질 향상을 위한 디지털 홀수고조파 반복제어기 설계기법에 대해 기술한다. 반복제어기의 설계를 위해 전체 제어시스템을 설계하고, 반복제어기가 안정하기 위한 기준을 제시한다. 비선형 부하에 대해 반복제어기를 적용함으로써, 인버터 출력전압의 홀수고조파 성분을 효과적으로 보상할 수 있으며, 이를 모의실험 및 실험으로 확인한다.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.183-184
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• 2017

엘리베이터의 경우 정전 시 승객을 안전하게 구출하기 위한 장치가 필요하다. 이를 위하여 Auto Rescue Device(ARD) 혹은 Uninterruptible Power Supply(UPS)가 엘리베이터에 설치된다. ARD는 정전 시 배터리의 전압을 승압하여 인버터의 DC 링크 전압을 유지한다. 만약 배터리의 전압보다 DC 링크 전압이 2배 이상 클 경우 일반적인 부스트 컨버터는 효율 등의 문제로 사용이 어렵다. 이에 본 논문에서는 ARD의 특성을 고려한 LLC 공진형 컨버터의 설계 방안에 대하여 서술하였다. 또한 이를 모의실험을 통하여 검증하였다.