• 컴퓨터교육학회논문지
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• 제5권1호
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• pp.57-66
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• 2002

컴퓨터와 인터넷 기술의 비약적인 발전으로 인해 인터넷상에서의 실시간 멀티미디어 서비스가 가능해짐에 따라 주문형 비디오(Video on Demand ; VOD)서비스나 GVA기술을 이용한 원격 교육이 시도되고 있다. 그러나 현재 VOD나 GVA서비스는 양질의 비디오화면을 실시간으로 서비스하는 서버의 연구나 효율적인 교육내용에만 집중되어 있을 뿐 사용자를 위한 서비스 형태에 대한 개발은 거의 이루어지지 않고 있다. 따라서 본 논문에서는 VOD나 GVA 서비스를 이용하여 원격교육을 받고자 하는 사용자 측면의 정보 서비스를 위한 서비스 시스템을 설계하고 구현하였다. 본 논문에서 설계한 주문형 멀티미디어 서비스 시스템은 E-mail올 이용한 오프라인 검색 서비스, PUSH 기술을 이용한 주기적인 최신정보 서비스, SDI서비스를 이용한 고객 맞춤 예약정보서비스와 피드백 서비스를 제공함으로서 사용자가 원하는 교육 자료를 선별하고 검색하는데 있어 걸리는 노력과 시간을 최대한 단축시키고, 서버에 접속하는 횟수를 최대한 줄여서 보다 고차원적인 정보 서비스를 받을 수 있도록 하였다.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2207-2212
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• 2012

Dimethylaluminum isopropoxide (DMAI, $(CH_3)_2AlO^iPr$) as a single precursor, which contains one aluminum and one oxygen atom, has been adopted to deposit non-stoichiometric aluminum oxide ($AlO_x$) films by low pressure metal organic chemical vapor deposition without an additional oxygen source. The atomic concentration of Al and O in the deposited $AlO_x$ film was measured to be Al:O = ~1:1.1 and any serious interfacial oxide layer between the film and Si substrate was not observed. Gaseous by-products monitored by quadruple mass spectrometry show that ${\beta}$-hydrogen elimination mechanism is mainly contributed to the $AlO_x$ CVD process of DMAI precursor. The current-voltage characteristics of the $AlO_x$ film in Au/$AlO_x$/Ir metalinsulator-metal (MIM) capacitor structure show high ON/OFF ratio larger than ${\sim}10^6$ with SET and RESET voltages of 2.7 and 0.8 V, respectively. Impedance spectra indicate that the switching and memory phenomena are based on the bulk-based origins, presumably the formation and rupture of filaments.

• 설비공학논문집
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• 제27권10호
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• pp.527-536
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• 2015

Studies for the reduction of lighting energy have been done using technologies such as user and location awareness. However, the focus of current research on location-based lighting control has been on energy reduction, which can lead to other issues including an imbalance in indoor illumination. This study proposes a lighting control system applying general illumination and technology for user and location awareness. The proposed lighting control system reduced lighting energy by 72.1%, 66.5% and 62.3% for 1, 2 and 3 users, respectively, compared to the On/Off lighting control system. This lighting control system causes an increase in lighting energy of 35.8% and 10.9% for 1 and 2 users compared to the lighting control system with user and location awareness, while a reduction of 9.4% was seen for 3 users. This means that the proposed system provides more effective energy reduction for a room with multiple occupants as it is based on the general lighting control scheme. The lighting control system applying general illumination and technology of user and location awareness improved the uniformity factor by 32.0%, 39.4% and 33.4% for 1, 2 and 3 users, respectively.

• 한국철도학회논문집
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• 제19권2호
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• pp.117-123
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• 2016

철도차량용 직류 고속도 차단기(HSCB)는 주 회로에 흐르고 있는 전류를 정상 차단시 아크 슈트 내부에서 발생아크를 소호하여 접지사고를 방지하는 기능으로 사용되고 있다. 선로에 사용되는 접촉기의 개방시에 발생하는 아크를 연구하기 위하여 아크 구현, 외부자계 등에 의한 효과적인 아크 소호의 방식 정립 및 아크 자기 구동력의 해석이 필요하다. 본 논문은 전자접촉기의 정상 차단시 발생하는 아크를 자속밀도 차와 로렌츠력을 통하여 소호능력을 예측하였다. 아크 슈트 내부의 그리드 개수와 형상은 내부 자계 형성에 영향을 미치므로, 유한 요소법을 이용하여 그리드의 변화에 따른 아크 소호능력을 연구하였으며 정격전압에 따른 그리드의 소호능력 평가와 그리드 형상 특성을 해석하였다.

• 한국수소및신에너지학회논문집
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• 제27권1호
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• pp.49-62
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• 2016

In this study, a solid oxide fuel cell (SOFC) system model including balance of plant (BOP) for building electric power generation is developed to study the effect of operating conditions on the system efficiency and power output. SOFC system modeled in this study consists of three heat-exchangers, an external reformer, burner, and two blowers. A detailed computational cell model including internal reforming reaction is developed for a planer SOFC stack which is operated at intermediate temperature (IT). The BOP models including an external reformer, heat-exchangers, a burner, blowers, pipes are developed to predict the gas temperature, pressure drops and flow rate at every component in the system. The SOFC stack model and BOP models are integrate to estimate the effect of operating parameters on the performance of the system. In this study, the design of experiment (DOE) is used to compare the effects of fuel flow rate, air flow rate, air temperature, current density, and recycle ratio of anode off gas on the system efficiency and power output.

• 한국의상디자인학회지
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• 제16권4호
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• pp.205-215
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• 2014

This study analyzed 'The representation of death' as expressed in the fashion photography posted on Facebook. Currently, there is a growing interest in 'Well-dying'. Also contemporary art and fashion is a trend that expressed what about death more than life. And today, Facebook is one of the current worldwide as a powerful communication. Death representation in contemporary fashion photography, as expressed in its first characteristic is 'Vanitas', and the main material was a skull. The shape of a skeleton of the symbol of death. Vanitas of inner meaning is vain, a mortal life's futility and death for the paradoxical emotion. The second characteristic is 'Phantom of the ruins'. This is like the darkness of death, and the shape represented in that space. And the death representation is depressed, gloomy atmosphere, dead-man and warm-less. Inner meaning is curiosity about the ghosts and the decadence romantic about the afterlife. The last characteristic is 'Grotesque'. This characteristic is the destruction of the body, fear of sadistic, and inhuman shape. This is parable with death that pain and fear of death, dark fantasy, the appearance of a contradiction modern society and cut off humanity. Inner meaning is the dark fear of death and the anger of wrong of the present society. At present, we have to reproduce the death, and what we want is eventually no one can escape 'Attention to death'. In addition, by expressing the solidarity between death and life is to want to get a consolation for the anxiety and afraid reality.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.499-502
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• 2007

정부는 기존의 품셈에 의한 예정가격 산정 방식을 폐지하고, 실적계약 단가를 근거로 하는 실적공사비 적산제도를 도입하여 시행중에 있다. 그러나 현재 BTL 교육시설물 예정가격 산정방법의 경우 표준화된 작업분류체계(WBS : Work Breakdown Structure) 및 내역서 작성지침의 부족으로 인하여 단가 산정에 정확한 근거 마련이 힘든 실정이다. 따라서 본 연구에서는 BTL로 발주된 교육시설물의 내역서를 바탕으로 BTL 교육시설물의 실적공사비 적용을 위한 작업분류체계(WBS : Work Breakdown Structure) 구축을 목적으로 한다. 이를 통해 일반 시설물과는 다른 특징을 가지는 교육시설물 분류체계를 구축하고 이를 이용한 공사비 항목 및 유지보수비 항목의 체계화가 가능할 것으로 예상된다.

• 한국통신학회논문지
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• 제36권3A호
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• pp.189-197
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• 2011

무선 광 통신 시스템에서 고속의 데이터를 전송하기 위한 방법으로 대역 효율이 높은 OFDM(orthogonal frequency division multiplexing) 시스템이 연구되고 있다. OFDM 시스템은 PAPR(peak to average power ratio)이 높고 비선형 에러와 디바이스의 불균형으로 발생하는 ICI(inter channel interference)가 발생한다. 무선 광통신 시스템에서 LED(light emission diode)의 구동 전류에 의하여 구동되는 광 출력 파워는 비선형이며 전송 신호는 왜곡된다. 그러므로 비선형 LED 전달함수와 OFDM 신호에 의한 방사된 광 출력의 수신 성능에 대한 연구가 진행되었다. 비선형 왜곡에 의해 발생하는 효과는 기존의 무선 통신에서 사용되는 OFDM의 비선형 특성과 다르며 BER 성능을 저감시킨다. 본 연구에서는 최근 연구된 LED의 비선형성 전달함수를 적용하며, 비선형 왜곡과 Back-off에 의하여 수신기의 주파수영역에서 진폭 감쇄와 ICI를 발생시키므로, BER 성능을 개선시키기 위한 방법을 제안한다. 먼저 LED의 비선형 왜곡을 감소시키기 위한 새로운 PAPR저감 기법을 제안하며, 또한 수산 성능을 향상시키기 위하여 적응형 채널 추정 방식과 전송된 신호를 사용하여 SNR(signal to power ratio)을 개선하여 BER(bit error rate)을 개선하였다. 제안된 방법들을 시뮬레이션 결과를 통하여 확인한다.

• Journal of Communications and Networks
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• 제18권4호
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• pp.559-566
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• 2016

Software defined network (SDN) can effectively improve the performance of traffic engineering and will be widely used in backbone networks. Therefore, new energy-saving schemes must take SDN into consideration; this action is extremely important owing to the rapidly increasing energy consumption in telecom and Internet service provider (ISP) networks. Meanwhile, the introduction of SDN in current networks must be incremental in most cases, for technical and economic reasons. During this period, operators must manage hybrid networks in which SDN and traditional protocols coexist. In this study, we investigate the energy-efficient traffic engineering problem in hybrid SDN/Internet protocol (IP) networks. First, we formulate the mathematical optimization model considering the SDN/IP hybrid routing mode. The problem is NP-hard; therefore, we propose a fast heuristic algorithm named hybrid energy-aware traffic engineering (HEATE) as a solution. In our proposed HEATE algorithm, the IP routers perform shortest-path routing by using distributed open shortest path first (OSPF) link weight optimization. The SDNs perform multipath routing with traffic-flow splitting managed by the global SDN controller. The HEATE algorithm determines the optimal setting for the OSPF link weight and the splitting ratio of SDNs. Thus, the traffic flow is aggregated onto partial links, and the underutilized links can be turned off to save energy. Based on computer simulation results, we demonstrate that our algorithm achieves a significant improvement in energy efficiency in hybrid SDN/IP networks.

• 한국응급구조학회지
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• 제22권1호
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• pp.83-97
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• 2018

Purpose: The purpose of this study was to provide basic data for the development of personal protective equipment (PPE) for emergency medical technicians (EMTs) during chemical, biological, radiological, nuclear, and explosive situations. Methods: Body measurements were obtained for adults aged from 20 to 59 years from the data in the 6 th Size Korea national sizing survey. These data were compared to the sizes of protective clothing currently available in the market. In-depth interviews with active paramedics with experiences of wearing PPE were conducted. Results: Most of the imported protective clothing turned out to be unfit for Korean adults. This showed the urgent need for developing appropriately sized protective clothing for Korean emergency technicians. In total, 55.0% of the respondents indicated that the current protective clothing is unsafe, and 71.0% requested the clothing to have level C protective performance. Regarding the design, many people wanted hooded all-in-one type of clothing. Conclusion: Considering these requirements, most of the wearers wanted their protective clothing to be fundamentally protective of their body, be available in various sizes with adjustable parts, and easy to wear and take off. They also wanted the clothing to be secure in clear sight, while not revealing any parts of their body and not interfringe with their ability to communicate with others.