• 한국안전학회지
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• 제32권6호
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• pp.22-28
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• 2017

According to the National Fire Data System (NFDS), more than 5,000 vehicle fires have occurred every year for the last 10 years. Vehicle fires are primarily caused by mechanical (breaking system and engine), electrical (wiring and battery), and chemical (oil and fuel gas leakage) problems. The electrical factor has increased with the installation of driver convenience equipment. For example, today, the black box is widely used to provide video data recording of motor vehicle accidents. The black box consists of a front camera, rear camera, and wires. The black box wires are directly connected to the junction box or fuse box from the start battery that operates to provide normal on power supplying for engine stop. It is extremely dangerous when the wires short circuit due to insulation aging, mechanical and electrical stress, etc. In this study, the black box wiring fire risk have been analyzed and investigated when the steady state and abnormal operations, and under the following conditions: wiring arrangements with a high temperature condition, insulation aging, poor contact, and short circuits. The results showed that black box wiring short circuits had a higher fire risk than the other fire hazard elements. To prevent fire hazards caused by black box wiring, the black boxes must be installed by qualified service personnel. Do not modify the wiring, remove the fuse and secure the wiring using cable ties or insulation tape.

• 한국화재소방학회논문지
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• 제20권1호
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• pp.71-76
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• 2006

전기화재의 주된 원인은 단락 및 과부하 사고, 누전 및 접촉불량 등으로 구분되며, 화재의 발생요인은 이들 사고에서 동반되는 아크나 스파크로 인한 화재가 대다수이다. 저압배전선로에 사용되는 고감도형 누전차단기는 누전과 과부하를 검출하여 차단하는 기능은 있으나, 전기화재의 직접적인 위험요소인 아크나 스파크 현상에 대한 차단기능은 없는 것으로 분석된다. 이것은 저압 분전반에 적용되는 누전차단기의 경우 정격차단시간이 30[ms](KS C 4613)로 정해져 있어, 더욱 낮은 레벨로 주기적으로 발생되는 아크나 스파크를 감지하지 못하기 때문이다. 이러한 문제점을 개선하기 위하여 본 논문에서는 전기화재에 기인되는 아크나 스파크에 대해 누전차단기를 트립시키는 보조제어장치를 제안하고, 제안된 보조제어장치의 이론적 해석과 실험측정을 통해 그 타당성을 입증시킨다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.371-372
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• 2007

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device (RCD), that is Earth Leakage Circuit Breaker(ELB) and Molded_case Circuit Breaker (MCB), of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms] (KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this research development is proposed to a auxiliary control apparatus for RCD trip on electric arc or spark due to electrical fire. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.

• 한국생산제조학회지
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• 제22권1호
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• pp.138-144
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• 2013

The automation technology for overlay welding is needed due to the occurrence of severe corrosion and abrasion on the surface of internal contact in different shape of fittings. In Korea, different shapes of fittings have been manufactured by using the imported equipment of overlay welding automation at some companies. Thus the research on the development of overlay welding automation system (in short, OWAS) for a large L-type tube is urgently needed. In this paper, the investigation is focused on the optimal design of a supporting base for the (currently developing) OWAS of large L-type tube. Specifically we assume that the base which supports the equipment during the process of overlay welding is loaded as self-weight in the direction of gravity through static analysis especially when it is rotated 180 degree on the OWAS. For optimal design of a supporting base for OWAS of large L-type tube, Solidworks(R) (for 3-dimensional modelling) and ANASYS Workbench(R) (for structural analysis) are incorporated so as to proceed an optimization routines based on Response Surface Method (RSM) and Design of Experiment (DOE). In more specific, DOE finds out major factors (or dimensions) of the supporting base by using MINITAB(R). Then the regression equations between design variables (the major factors of supporting base) and response variables (deformation, stress and safety factor for the supporting base), which will be resulted in by RSM, verify the major factors of DOE. In the next step, Central Composite Design (CCD) plans 20 simulations of ANASYS Workbench(R) and then figures out the optimal values of design variables which will be reflected on the manufacturing of supporting base. Finally welding experiment is conducted to figure out the influence of overlay welding quality in applying the optimized design values of supporting base to the actual OWAS.

• 한국가스학회지
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• 제10권2호
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• pp.1-6
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• 2006

본 연구에서는 실내 오염물질인 포름알데히드가스를 제거하기위하여 $Pd/TiO_2$로 코팅한 극세 섬유에 광분해 효과를 제안하였다 광촉매 반응기는 사각박스(부피 2 l)내에 UV램프와 $Pd/TiO_2$로 코팅한 극세 섬유와 함께 장착하였다. 이 때 Langmuir-Heinshelwood의 반응속도와 흡착상수, 온도 및 농도 변화에 따른 전환을 그리고 습도변화와 오염가스($SO_2$) 혼합으로 인한 전환율의 영향을 조사하였다. 결과로서 속도상수(k)와 흡착상수($\beta$) 각각 114.94 ppmv/min, $0.0036ppmv^{-1}$을 얻었다. 또한 온도증가($40^{\circ}C{\sim}80^{\circ}C$)에 따른 포름알데히드가스 전환율이 약 20%로 감소하고 습도변화에 따른 전환율에서는 습도가 증가할수록 감소하는 경향을 보였다. 이외에 $SO_2$가스 혼입되어 있는 상태에서 전환율은 $SO_2$ 가스가 수분에 의한 이온의 영향으로 방해인자로 작용하는 것을 알 수 있었다.

• 농촌계획
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• 제21권2호
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• pp.163-175
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• 2015

This study aimed to analyze factors of importance and performance picked by customers of Bibijeong, a farm restaurant operated by the local community of Wanju-gun. Major points include: Recognition paths mostly were word of mouth and mass media, types of visit were in the company of friends, family members or work colleagues, and purposes of visit included consumption of meal and identifying features of the restaurant. Secondly, factor analysis showed that level of facility, atmosphere/cleanness, diversity of menu, employees, ingredients and network. The Cronbach Alpha coefficient was +0.6. Thirdly, average of importance of factors was 3.861 while average performance was 3.429. IPA analysis showed that employee(communication, customer contact) in the first quadrant proved the need for fast improvement through training. Atmosphere/cleanness (interior atmosphere, table clean, kitchen cleanliness, clean dishes, interion design) and employee(proficiency, menu recognition), foodstuff(freshness, origin, safety) in the second quadrant showed that the marketing strategy of improvement as well as maintaining current status is needed, including regular training and hygiene inspection. The third quadrant contains facilities(disability, baby, fire protection) and food menu(food packing, various menu, creative menu, menu description), network(village economic links), which showed the need for gradual improvement. The forth quadrant contains network(sights's near contains. The results so far can be summed into the statement that overcoming the basic functionality of providing meals and linking the restaurant with local attractions and local economy would be need, as well as building up the image of unique farm restaurant with local features, so that Bibijeong can serve as the centerpiece of community and foundation of exchange with other areas.

• 대한기계학회논문집A
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• 제41권10호
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• pp.1005-1009
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• 2017

본 연구에서는 수중폭발에 의한 가스터빈 패키지에 작용하는 충격하중을 평가하고, 충격하중에 대한 가스터빈 패키지의 내충격 안전성을 검토하였다. 이를 위해 먼저 BV043에 따른 시간이력 충격하중을 산출하고, 산출된 충격하중을 바탕으로 이상화된 WEM(Whole Engine Model, 전체시스템)에 대한 시간영역에서의 과도응답해석을 수행하였다. 이를 통해 가스터빈 패키지의 주요구성품에 전달되는 하중을 평가하였으며, 평가된 전달하중을 바탕으로 주요구성품의 상세모델에 대한 내충격 안전성 검토를 수행하였다. 검토결과 가스터빈 패키지는 기준응력 대비 최소 1.0 이상의 안전율을 가지는 것을 확인하였다. 그리고 실물테스트를 통해 가스터빈 패키지 엔진제어시스템(EMS : Engine Management System) 구조 및 제어기능의 내충격 건전성을 검증하였다.

• 한국생활과학회지
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• 제17권6호
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• pp.1215-1224
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• 2008

This research has measured the indoor environment of thirty hair salons, which are located on Gunsan-Si, Jeonlabbuk-Do, from April 1st to April 30th 2005, to examine the related factors on a work environment of hairdressers and a revelation of respiratory symptom, and has polled 260 hairdressers and 350 office workers. After measuring the physical environment of hair salons, the room temperature, the relative humidity and the illumination was in an agreeable range, and 60 percent of hair salons depended on the natural ventilation through the windows. The levels of acetone, toluene and xylene, which were measured at the hair salons, were all under the safety standards (p<0.05), but these are still harmful and volatile matters, so they can be bad for your health by the contact of skin and respiration. The harmful factors that affect a revelation of respiratory symptom were the group who has many exposures of permanent wave or bleaching/dyeing and not many experiences of hairdressing work, the group who smokes every day, and the group who never exercises at all (p<0.05). This result shows that there are possibilities of health problem for hairdressers from the constant and repeating hairdressing works with the exposure of chemicals such as the permanent, bleaching and dyeing. so that hairdressers recognize that they need appropriate ventilation facilities for their agreeable indoor-environments. And also, to prevent the direct exposure of chemicals as much as they can, they need to have an active management of an individual health care by wearing gloves, mask or something like that.

• 한국구조물진단유지관리공학회 논문집
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• 제22권2호
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• pp.43-50
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• 2018

본 연구에서는 강주형과 바닥판의 합성에 사용되는 전단연결재에 대한 연구를 위해 세계 각국에서 사용되는 설계기준과 연구사례를 분석하고 교량 바닥판에 작용하는 각종 수직하중으로 인해 강주형과 콘크리트 슬래브의 접촉면에 발생하는 수평방향의 전단력을 전달하는 이 연결재를 설치한 밀어내기 시험체에 대하여 전단실험을 수행하였으며, 이 시험을 통하여 철근 대신 FRP 철근이 배치된 Steel strap 바닥판의 전단열재 평가식을 제안하였다. 본 연구에서의 제안식은 도로교설계기준의 전단연결재 허용강도 대비 약 3배의 안전율을 가지고 있으며, 기존의 DIN 기준과 Viest 평가식과 비교하면 5%정도의 오차로 유사한 결과를 보여주었다.

• 한국학교ㆍ지역보건교육학회지
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• 제24권4호
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• pp.13-26
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• 2023

Objectives: The purpose of this study was to explore the factors that influence aerobic physical activity among Korean adults, including sociodemographic characteristics, health behavior, health status, social relationships, community satisfaction, and to find ways to increase aerobic physical activity among adults. Methods: In 2019, 191,152 adults in the Community Health Survey were analyzed, and complex sample frequency analysis, Rao-Scott test and complex sample logistic regression analysis were conducted by dividing them into the presence or absence of aerobic physical activity practice. Results: The rate of aerobic physical activity among adults was 36.0%, and males were higher than females. Among individual factors, gender, age, income level, smoking, drinking, weight control attempt, frequency of breakfast, obesity, quality of life, and subjective health status were factors that had a significant effect. Among social relationship factors, leisure activities and contact with neighbors at least once a week were significant factors, and only overall safety level satisfaction was a factor that had a significant effect on physical activity practice in community satisfaction factors. Conclusion: Programs focused on personal factors, social relationships, and networks should be strategically developed to improve the participation rate of adult aerobic physical activities, indicating the importance of these factors over community infrastructure. To development of community-centered professional integrated health education will be necessary in the future.