• Journal of Platform Technology
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• 제6권3호
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• pp.38-46
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• 2018

스마트 그리드는 전력 생산자와 소비자 간의 양방향 통신을 통해 효율적으로 전력을 생산 및 소비하기 위한 지능형 전력망이다. 신재생 에너지가 발전하면서 신재생 에너지가 스마트 그리드에서 차지하는 비율이 점점 높아지고 있다. 신재생 에너지는 발전량이 실시간으로 변하기 때문에 발전량의 예측 및 조절이 가능한 기존의 발전 방식과는 다른 문제점이 있다. 스마트 그리드에 자가 적응 프레임워크를 적용하는 것은 실시간으로 변하는 신재생 에너지의 발전량에 적응함으로써 스마트 그리드의 효율적인 운영을 가능케 할 것이다. 본 논문에서는 태양광 발전 시설이 설치된 스마트 마을을 가정하고 이에 자가 적응 프레임워크인 AiTES 를 적용 하여 자가 적응 프레임워크를 통해 스마트 그리드의 효율적인 운영이 가능함을 보였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.255-258
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• 2009

Leading developed countries have studied energy self-sufficient houses such as zero or low energy buildings to reduce energy consumption for buildings since the early 1990s. Moreover, some developed countries have actually constructed self-sufficient houses and operated them for demonstration, expanding use of such houses. Korea has also established Zero Energy Solar House(ZeSH) and studied energy independence. Therefore, this study analyzed research result regarding ZeSH, self-sufficient energy house hold of Korea, found out technologies used for heating energy independence, used building interpretation program(ESP_r) to evaluate performance of each factors and analyzed energy reduction quantitatively. Results from the research are as follows: Reduction rate of actual detached house's heating load was also analyzed quantitatively depending on application of each technology. When each factor was applied step-by-step, annual reduction rate of heating load depending on increase in insulation thickness reached 6.6~22.2 %. Annual reduction rate of heating load depending on increase insulation thickness, and change in window heating performance and area ratio reached 31.5 %. Annual reduction rate of heating load through high-sealing and high-insulation depending on change in leakage rate reached 40.0~88.9 %. Annual reduction of heating load, when Mass Wall and attached sun space was applied were applied reached 28.5~39.2 %, respectively.

• International Journal of Precision Engineering and Manufacturing-Green Technology
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• 제5권5호
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• pp.643-650
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• 2018

A self-powered electrochromic device was fabricated on an indium tin oxide-polyethylene naphthalate flexible substrate using a dye-sensitized solar cell (DSSC) as a self-harvesting source; the electrochromic device was naturally bleached and operated under outdoor light conditions. The color of the organic electrochromic polymer, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, was shifted from pale blue to deep blue with an antimony tin oxide film as a charge-balanced material. Electrochromic performance was enhanced by secondary doping using dimethyl sulfoxide. As a result, the device showed stable switching behavior with a high transmittance change difference of 40% at its specific wavelength of 630 nm for 6 hrs. To improve the efficiency of the solar cell, 1.0 wt.% of Ag NWs in the photoanode was applied to the $TiO_2$ photoanode. It resulted in an efficiency of 3.3%, leading to an operating voltage of 0.7 V under xenon lamp conditions. As a result, we built a standalone self-harvesting electrochromic system with the performance of transmittance switching of 29% at 630 nm, by connecting with two solar cells in a device. Thus, a self-harvesting and flexible device was fabricated to operate automatically under the irradiated/dark conditions.

• Educational Technology International
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• 제22권1호
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• pp.57-85
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• 2021

The purpose of this study was to identify learners' perception of teaching activities in online classes that were forcibly switched due to COVID-19, and to compare and analyze differences in importance and performance of online teaching activities according to the level of self-directed learning in university students. To address these goals, 31 university students who took courses operated as online classes at university participated in this study, and the collected data were analyzed according to IPA procedures and methods. As a result, for online teaching activities, class attendance check and encouragement, clarity of class objectives, the ability to deliver the content of learning, and the ability of the instructor to deliver lectures were identified as factors to be constantly emphasized. Depending on the level of self-directed learning, there were significant differences between importance and performance in high level learners' interaction strategy with instructor, interaction strategy with learner, and timely provision of instructor's feedback. On the other hand, there was no significant difference between the importance and performance of online teaching activities for learners with a low level of self-directed learning. Based on these research results, several implications for the design of effective online teaching activities in future university education were proposed.

• 보건교육건강증진학회지
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• 제24권4호
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• pp.131-147
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• 2007

As overweight and obese people have increased, obesity management programs have generated much concern in Korea. Many types of obesity management programs were operated, aimed at reducing weight, BMI, body fat percentage and so on. This study was conducted to review the features of studies in obesity management programs and systematically assess the effects which were published from 1995 to 2006 in Korea. Databases were systematically searched for published data in Korea. It were KISS (Korean studies information services system) and KERIS (Korean Education research information system), which were major literature search systems for all academic fields in Korea. Total 114 studies were initially identified, of which 21 satisfied our inclusion data. The effects of obesity management programs were assessed on the results in weight, BMI (body mass index), HDL (high density lipids), body fat percentage, self-efficacy. Effect size estimated on the equation of M1 - M2 / Sp, where M1 was mean of the experimental group, M2 was the mean of control group, and Sp was the pooled standard deviation. Magnitude of effect size was interpreted by using Cohen's definition. Cohen described small, medium, and large effect sizes as 0.2, 0.5, and 0.8 respectively. The studies about obesity management programs were the most published in 2005(26.1%). Obesity management programs were popularly operated as the type of 12 weeks intervention, exercise intervention(52.4%), quasi-experimental study(85.7%). Ten studies reported significant effects on weight, and nine studies reported significant effects on BMI and HDL. Only five and three studies reported significant effects on body fat percentage and self-efficacy respectively. The effects of each outcome were generally significant when the studies included these elements, intervention over 10 weeks, evaluation over 3 times, a comprehensive program (exercise, nutrition education, behavior modification) and reinforcing factors (self-monitoring, group discussion, one's goal setting, and etc.). Effective obesity management programs should contain these essential elements and objectives of obesity management programs must be set out evident at the beginning. The participants should be registered, educated and evaluated by continuous obesity management programs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.475-478
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• 1995

The variations of cold gas properties such as density, pressure, temperature and velocity which are dependent each other are closely related with the dielectric recovery of an interrupter. So, the pressure-rises at no-load in the puffer cylinder and in front of fixed arcing contact of 800kV model interrupter were measured experimentally using pressure transducers of strain gage type and semiconducting type, respectively. The maximum value of pressure-rise in the puffer cylinder increased almost linearly from 7.6 bar at the minimum operated pressure to 9.7 bar at the maximum operated pressure, while the pressure-rise in front of fixed arcing contact was independent with the operated pressure. The measured values will be utilized in verifying the self-developed cold flow analysis program and as an input of commercialized CFD program package.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1368-1370
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• 2005

Satellite is operated only with internal battery when separated from rocket. Internal battery is charged only from SAR(solar Array Regulator), solar cell. So battery will be exhausted and purpose of satellite will be failed if load module is out of order or short. This paper proposed real time current limiter which operated by telemetry of outer processor. This current limiter operates by control signal simultaneously cuts off over current by self over current sensing circuit. So it can reduce waste of battery energy and over load of outer processor.

• 한국융합학회논문지
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• 제12권9호
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• pp.307-314
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• 2021

본 연구는 셀프리더십, 진로결정 자기효능감, 비판적 사고성향이 간호대학생의 진로준비행동에 미치는 영향을 파악하기 위해 시행된 서술적 조사연구이다. G시와 M시의 간호학과에 재학중인 간호대학생을 대상으로 2019년 4월부터 6월까지 자료를 수집하였고 208명의 자료를 분석하였다. 자료는 기술적 통계, 독립표본 평균 검정, 일원 배치 분산분석, 피어슨 상관계수, 다중회귀분석을 실시하였다. 분석 결과, 셀프리더십(β=.331, p<.001)과 진로결정 자기효능감(β=.302, p<.001)은 진로준비행동에 정적으로 영향을 나타냈으며, 연구모형은 진로준비행동을 38.7% 설명하였다. 이러한 연구 결과를 통해 간호대학생의 진로준비행동을 촉진하기 위해 셀프리더십과 진로결정 자기효능감을 향상키기기 위한 방안들이 간호교육 현장에서 개발 및 운영되어야 함을 알 수 있다.

• Communications for Statistical Applications and Methods
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• 제19권3호
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• pp.459-469
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• 2012

본 연구에서는 자기조직화 신경망이 필요한 노드만을 가지고 최적화하여 정규혼합분포를 추정하는 모형(Ahn과 Kim, 2011)을 Java언어에서 제공하는 스레드(thread)를 기반으로, 멀티코어 컴퓨팅환경에서 병렬처리방식으로 구현하여 순차처리방식에 비해 짧은 연산시간으로 정규혼합모형의 추정이 가능함을 보이려고 한다. 이를 위하여 Ahn과 Kim이 제안한 모형을 바탕으로 두 가지의 병렬처리 방법을 제안하고 그 성능을 평가하였다. 병렬처리 방법은 Java의 멀티스레드를 이용하여 구현되었으며, 모의실험을 통하여 제안한 모형이 순차처리방식과 비교하여 수렴속도가 빠름을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.158-158
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• 2009

This paper focuses on improving organic thin film transistor (OTFT) characteristics by controlling the self-organization of pentacene molecules with an alignable high-dielectric-constant film. The process, based on the growth of pentacene film through high-vacuum sublimation, is a method of self-organization using ion-beam (IB) bombardment of the $HfO_2/Al_2O_3$ surface used as the gate dielectric layer. X-ray photoelectron spectroscopy indicates that the IB raises the rate of the structural anisotropy of the $HfO_2/Al_2O_3$film, and X-ray diffraction patterns show the possibility of increasing the anisotropy to create the self-organization of pentacene molecules in the first polarized monolayer. An effective mobility of $2.3{\times}10^{-3}cm^2V^{-1}s^{-1}$ was achieved, which is significantly different from that of pentacene films that are not aligned. The proposed OTFT devices with an ultrathin $HfO_2$ structure as the gate dielectric layer were operated at a gate voltage lower than 5 V.