• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.184-191
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• 2016

In recent years, there are a number of studies that have been carried out to explore the alternative for Mineral Oil (MO) as dielectric insulating fluid in transformers due to the increasing tight regulation on safety and environment. Vegetable oils have been identified as suitable candidate since it is biodegradable, non-toxic and high flash/fire points which ensure more in-service safety. Among the types of vegetable oils considered for transformers application are Palm Oil (PO) and Coconut Oil (CO). This paper presents an experimental study on the lightning breakdown voltages of PO and CO under non-uniform electric field based on needle-sphere electrodes configuration at 3 small gap distances. The type of PO used in this study is Refined Bleached and Deodorized Palm Oil (RBDPO) Olein. The main focus of this study is to examine the lightning breakdown performance of RBDPO and CO under different test conditions and assess its suitability as dielectric insulating fluid in transformers. The effect of voltage polarities (positive and negative) and testing methods (rising-voltage, up-and-down and multiple-voltage) were investigated. The data obtained from all tests were analysed by Weibull distribution in order to determine the withstand voltages for each type of oils. It was found that the breakdown voltages of RBDPO and CO are comparable with MO under positive lightning impulse. Under negative lightning impulse, the breakdown voltage of MO is slightly higher than RBDPO and CO. There is no significant effect of testing methods and voltage polarities on lightning breakdown voltages of RBDPO and CO. Based on the statistical analysis, it is found that the breakdown voltages of RBDPO and CO at 1% probability are slightly lower than MO.

• 대한환경공학회지
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• 제31권4호
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• pp.272-277
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• 2009

국내 석탄화력발전소의 대용량 보일러를 대상으로 연소용 이차공기의 수평분사각을 변경한 경우에 대하여 화로에서의 연소특성과 NOx 발생특성을 전산유체역학적으로 해석하였다. 열유동해석 결과를 실제 운전데이터와 비교하여 해석의 신뢰성을 확인하할 수 있었다. 분사각을 $20^{\circ}$까지 증가시킬 경우 노즐 근처에서의 재순환유동 감소, 화로출구 NOx 감소와 미연분 증가를 가져왔으며 화구의 형태가 많이 변화되는 것을 관찰하였다. 본 연구결과는 A화력발전소의 연소방식을 변경하는 경우 기본적인 설계 및 운전 데이터로 활용하고자 한다.

• 한국산학기술학회논문지
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• 제17권7호
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• pp.536-542
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• 2016

본 사례 연구는 공업계 고등학교 학생들의 안전 및 안전교육에 대한 인식을 조사하기 위한 목적으로 수행되었다. 본 연구를 통해 공업계 고등학교 학생들의 안전의식에 대한 효율적인 교육을 위한 기초 자료를 제공하고자 하였다. 연구는 학교안전교육 분야 및 학교 생활안전 분야 각 7개 항목씩 모두 14개 항목에 대한 설문조사를 실시하는 것으로 진행하였다. 설문에 응답한 학생은 경기도 일개 공업계 고등학교 전자, 건축, 토목 관련학과에 재학하는 1학년과 2학년 학생 455명이다. 설문 결과는 SPSS win19.0을 이용하여 교차분석, 신뢰도분석 및 빈도분석 등의 통계처리를 하였다. 본 연구에서 설문의 신뢰성 Cronbach ${\alpha}$는 0.871~0.882 이다. 조사 결과에 따르면, 학생들은 현재 진행되고 있는 학교에서의 안전교육에는 흥미로운 내용이 없는 것으로 생각하고 있었다. 학교에서 안전교육은 학교생활에는 도움이 되지만 일상생활에 유용하지 않다고 생각하는 것으로 조사되었다. 조사대상 공업계 고등학교 학생들은 실험실에서 지켜야 하는 안전규정은 잘 지키고 있으나 보호 장구 착용은 잘 지켜지지 않는 것으로 조사되었다. 학생들이 안전에 대해 인식하고 있는 것과 실천하는 것에는 차이가 있어 생활에서 실천해야 하는 안전에 관한 의식은 상대적으로 낮은 것으로 나타났다.

• 한국간호교육학회지
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• 제24권2호
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• pp.190-200
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• 2018

Purpose: The purpose of this study was to identify the level of perception of safety risk factors and the degree of performance of safety nursing activities in order to develop an education program to improve the safety of patients. Methods: The subjects were 217 nurses from 3 university hospitals in Incheon. Data were collected with structured questionnaires and analyzed using descriptive analysis, t-test, and ANOVA using SPSS 22.0. Results: The level of perception of patient's safety risk factors and safety care activities was 2.93 and 4.68, respectively. Perception of patient safety risk factors which belonging to the risk type of therapeutic devices, equipment, service and infrastructure all scored below average; also in addition, behavior, performance, and violence risk type and work system, information and communication risk type showed relatively low perception levels. Safety nursing activities showed a low level of performance in accurate communication among medical teams, management of fire and disaster, security management, use of restraints, identification of patients, and correct performance of operations and procedures. Conclusion: Based on these results, it is necessary to improve the safety of patients by taking proper management measures along with education.

• 한국항해항만학회지
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• 제42권3호
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• pp.195-200
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• 2018

여객선은 선박사고가 발생을 하게 되면 인명의 피해로 직결되기 때문에 선장의 순간적인 결정이 매우 중요하다. 본 연구에서는 선박의 이상증후가 발생하였을 때 선박 및 승객대피 의사결정을 위한 주요요인을 정량적으로 분석하고 의사결정에 있어 기초 자료를 제공하고자 하였다. 8개의 주요요인에 대하여 전문가 설문조사를 실시하였으며 계층분석방법(Analytic Hierarchy Process: AHP)을 이용하여 가중치를 선정하고 우선순위를 결정하였다. 그 결과 가중치가 가장 높은 주요요인은 전복(횡경사 발생)이었으며, 그다음이 화재/폭발로서, 의사결정에 있어서 가장 큰 영향을 미칠 수 있다. 추후 세부 설문조사를 실시하여 유효수를 높여 신뢰도를 향상시킬 것이며, 본 결과는 선박과 승객대피 의사결정의 주요요인을 결정하는 기초자료로 활용 될 것이다.

• KIEAE Journal
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• 제13권5호
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• pp.79-88
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• 2013

This study creates the evaluation criteria to analyze the $CO_2$ emission quantity in the complex of apartment house among domestic buildings and proposes how to calculate the $CO_2$ emission quantity by the only simple information of apartment house. The study shows that in order to create the index of carbon emission evaluation criteria, $CO_2$ emission quantity for its input materials in these 27 apartment houses are 445,412g-$CO_2/m^2$ for apartment building, 474,322g-$CO_2/m^2$ for the basement parking lot, 483,523g-$CO_2/m^2$ for welfare facility, 729,957g-$CO_2/m^2$ for sales facility, 743,560g-$CO_2/m^2$ for other facility, 26,782g-$CO_2/m^2$ for public facility, 43,659g-$CO_2/m^2$ for landscape, 1,113g-$CO_2/m^2$ for indoor facility, 11,251g-$CO_2/m^2$ for outdoor facility and 891g-$CO_2/m^2$ for common temporary based on the average $CO_2$ emission by facility. We can also see the analysis data that in case of using the selected factors only, the rate of error is 7.51% comparing with the emission quantity by using simplified LCA method this study suggests for the whole range of apartment houses and the rate of error is average 3.24% using selective and main materials. And this it is evaluated that we can get the result which is similar to the actual $CO_2$ emission quantity with only the simple information about the apartment house.

• 한국응급구조학회지
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• 제11권1호
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• pp.73-80
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• 2007

This study is a descriptive survey research to know the levels of job satisfaction and influential factors for emergency medical technicians(EMT). This study sampled Level 1 and Level 2 Rescue Members from fire stations and EMT from general hospitals in the Gwangju City and JeollaNamdo area. Interviews for the 75 participants of this convenience sample were conducted for a two month period from July to September 2006. Data was collected on interviewing questionnaires. When looking at the results above internal factions were most influential towards satisfaction and self-responsibility, fulfillment, displays of Aptitude were highest for satisfaction. However, organizational factors were the lowest. There is a need for reform in promotion term periods and policy as well as promotion opportunities. Influential factors for job satisfaction were Role Performance Ability, Intentions for Changing Jobs, and Job Selection Motivation. Therefore, the more insufficient your ability to perform your job the less satisfied you are with it and the more fear you feel from experiences on the job the less satisfied you are with your job. Henceforth, there is a need to reform the educational programs offered to EMT for job training emphasizing job performance ability and the ability to judge for oneself on emergency situations, and reform the promotional system. Finally, there is a need for psychological consultation to offer stability to those after treating an emergency situation and encouragement for personal religion.

• 한국안전학회지
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• 제28권4호
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• pp.1-7
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• 2013

Train accidents can be directly connected to fatal accidents-collision, derailment, Fire, railway crossing accidents-resulting in tremendous human casualties. First of all, the railway derailment is not only related to most of railway accidents but also it can lead to much more catastrophic accompanying train overtured than other factors. Therefore, it is most important factor to ensure railway safety. some foreign countries have applied to the detector machines(e.g., ultrasonic detector car, sleep mode, current detector, optical sensing, optical fiber). Since it was developed in order to prevent train from being derailed. In korea, the existing track method has been used to monitor rail condition using track circuit. However, we found out it impossible for Communication Based Train Control system(CBTC), recent technology to detect rail condition using balise(data transmission devices) without no track circuit. For this reason, it is needed instantly to develop real-time monitoring system used to detect broken rails. Firstly, this paper presents domestic and international statues analysis of rail breaks technology. Secondly, the composition and the characteristics of the real-time monitoring system. Finally, the evidence that this system could assumed the location and type of broken rails was proved by the experiment of prototype and operation line tests. We concluded that this system can detect rail break section in which error span exist within${\pm}1m$.

• 전자공학회논문지 IE
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• 제48권2호
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• pp.61-70
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• 2011

IEEE 802.11 무선 네트워크에서는 프레임 충돌현상을 방지하기 위해 RTS/CTS와 같은 제어프레임을 지원한다. 하지만 제어프레임은 프레임 충돌 현상을 막지만 전송률을 떨어뜨린다. 또한, 이웃하는 셀이나 같은 셀에 있는 다른 노드들의 동작을 막아버리는 현상인 False Node Problem을 발생시키기도 한다. 비효율적인 전송률과 False Node Problem을 해결하기 위해 새로운 제어프레임을 제안한다. 새로운 제어 프레임은 기존의 프레임에서 채널 감지기능을 갖는 4바이트를 추가한 것이며, 채널 감지 기능은 데이터를 수신할 때 일정한 시간에 채널을 다시 감지한다. 이 기능으로 채널의 접속 빈도를 높이게 되어 False Node Problem을 방지할 것이라고 기대한다. False Node Problem 방지와 효율적인 전송률을 증명하기 위해 새로운 제어프레임과 기존의 제어프레임을 지연시간과 load을 비교 분석을 하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.425-428
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• 2006

In order to estimate the reduction of laodbearing capacity, followed by the attributive change of heat while high strength concrete structure is revealed on fire it is necessary to evaluate, it is necessary to evaluate the property of material under high temperature such as thermal conductivity, specific heat, compressive strength, modulus of rigidity and diminution figure. Therefore, this study is for the purpose of presenting evaluation data for the analysis of thermal behavior about the high strength concrete material under high temperature, through the experiment by manufacturing concrete(40, 50, 60, 80, 100 MPa) commonly used in the construction field. As a result of the study, in the case of physical attribute, it demonstrates a greater fluctuation of change than the one of 30 MPa concrete. In case of specific heat, the high strength concrete, shown the serious diminution between $500{\sim}600^{\circ}C$, presents the thermal change area corresponding to the change of high strength concrete. In compressive strength, regardless of intensity of concrete, all of them show the first intensity loss between normal temperature and $100^{\circ}C$, the dramatic loss beyond $400^{\circ}C$. The concrete weighing above 50 MPa shows a twice lower dramatic intensity loss than the one weighing $30{\sim}40MPa$. The concrete ranging from $60{\sim}80MPa$, shows the biggest diminution of modulus of elasticity under $400^{\circ}C$, which implies the structural unstability of temperature.