• 동력기계공학회지
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• 제10권2호
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• pp.22-28
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• 2006

Computer simulation of the air flow over an automotive vehicle is now becoming a routine process in automotive industry to assess the aerodynamic characteristics of a medium-size vehicle such as $C_d\;and\;C_1$ and aslo to investigate the possibility of improving aerodynamic performance of the vehicle as a preliminary design for the production line. Mainly due to its contribution in saving time and cost in the development of new cars, computer simulation of the air flow over a vehicle is usually done well before a production car is introduced to the market and in gaining more and more attention as powerful computer resources are getting readily available nowadays. To aerodynamically design a car is mainly related with reducing a drag coefficient of car. A well designed car usually has a $C_d$ value in the range of $0.3{\sim}0.4$. It is understandable that automotive industry is rushing to reduce a drag coefficient as reducing even a small fraction of the $C_d$ value can have an enormous overall impact on many areas. Actually, the present research model was able to achieve a $C_d$ value in the range of $0.3{\sim}0.36$ for flow velocities of $60km/h{\sim}100km/h$ by strategically removing the possible factor hazardous to lower $C_d$ value. Prediction of the medium-size vehicle aerodynamics using CFD was performed when an actual car model was in the development stage and three-dimensional modeling was also performed to optimize it as the best model in terms of the best aerodynamic performance.

• 한국환경보건학회지
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• 제43권2호
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• pp.157-166
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• 2017

Objectives: Exposure to hazardous air pollutants could be affected by sociodemographic factors such as age, gender and more. Information on time spent in microenvironments has a critical role in exposure assessment. The purpose of this study was to analyze the exposure pathways which influence personal exposure through time-activity patterns and sociodemographic factors. Methods: A total of 379 subjects were collected from the second term of the Korean National Environmental Health Survey. A questionnaire survey in relation to sociodemographic factors and a time-activity diary were carried out for personal exposure to toluene. Focusing on personal exposure to toluene, factors affecting personal exposure were analyzed using multiple regression analysis. Results: Participants spent their time in an indoor house for $16.8{\pm}4.0hr$, workplace or school $2.3{\pm}3.5hr$, and other indoor $2.1{\pm}2.2hr$. Sociodemographic factors were significantly different among each personal exposure and microenvironment. Time of staying at an office turned out to be a main factor from point of exposure in exposure pathway using multiple regression analysis. As a result, this means that exposure may be different according to the time of staying in each microenvironment. Conclusions: Personal exposure to air pollutants might be decided by time-activity pattern indicating when, where, and which activities people pursue, as well as individual sociodemographic factors.

• 한국분무공학회지
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• 제20권1호
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• pp.28-34
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• 2015

Recently, some researchers have been carried out risk assessment of vehicles exhaust on human health. Especially, some of VOCs which is non-controlled, was classified to hazardous pollutant, such as 1,3-Butadiene and BTEX(Benzene, Toluene, Ethylbenzene and Xylene). Therefore, the profile on non-controlled pollutant may be needed in the future, because it would be critical data or information to control them. Additionally, with increasing amount of motorcycle, the source profiling is essential for estimating emission factor and amount on motorcycle exhaust. For these, in this study, imported motorcycles (8 vehicles) were selected as a test model while considering the increasing ratio on sales volume between 2013 and 2014; it was also compared with domestic motorcycles on those. The experiment was conducted by driving mode, UDC and ECE+EUDC that made from EURO III. In addition, it was performed at cold start driving mode without effect by displacement, for evaluating only correlation of BTEX with HC. In order to apply the ratio (m,p-Xylene/o-Xylene) as a marker, the ratio was compared with those of tunnel, road side and residential area. As a result, it showed best correlation ($R^2=0.98$) among those. In the future, it has to be considered as a marker for effect evaluation to atmospheric environment by exhaust emission.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5792-5799
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• 2013

본 연구는 떡류의 HACCP(Hazard Analysis Critical Control Point)시스템 적용을 위한 목적으로 하였다. 떡의 주원료, 작업장 시설과 작업자 등에 대하여, 2012년 9월 12일~2013년 2월 13일까지 서울시 용산구 서계동 소재에 있는 KB 업체에서 제공받았다. 제조공정도는 일반적인 떡류 제조업체의 제조공정을 참고로 작성하였다. 제조공정도는 원료 농산물(맵쌀, 찹쌀, 팥 등), 부재료, 용수와 포장재료의 입고, 보관, 계량, 세척, 불림, 분쇄, 체선별, 혼합, 시루작업, 증자, 내포장, 금속검출, 외포장, 보관 및 출하공정으로 Fig. 1과 같이 작성하였다. 원료농산물의 미생물학적 위해요소 분석결과는 Table 1과 같다. 본 연구결과 떡의 원재료와 제품의 위해미생물검사 결과는 안전하나 제조환경과 작업자의 미생물검사 결과 체계적인 세척 및 소독을 실시하여 미생물학적 위해를 감소시키고 작업자 위생교육 등을 통하여 개인위생개념 향상과 작업장 내 공기중의 미생물 관리가 함께 이루어져야 할 것으로 여겨진다.

• 패션비즈니스
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• 제15권2호
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• pp.145-159
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• 2011

The study aimed to analyze the status quo of manufacturing work environment and the work clothes' clothing comfort and wearer mobility of welding and grinding work processes in the machine and shipbuilding industries in South Korea. A questionnaire survey was conducted for the study, which consisted of questions about work clothes' clothing comfort and wearer mobility according to body parts. The findings derived from the research were: the high impact levels of work environment factors on welding and grinding work processes were noise, metal fragment, superheat, toxic gas, UV ray factors. Subject workers' assessment of work clothes' clothing pressures were in the levels between 3 (i.e. moderate) and 4 (i.e. comfortable) in a range of 5-point scale. The impact levels of wearer mobility factor were high on the work processes of welding and grinding in machine and grinding in shipbuilding. While welding process in shipbuilding showed a 'moderate' wearer mobility level and this was because its work postures were uncomfortable yet the rate of the motion change was low. The consideration to develop the work clothes specialized for certain work processes should include the materials' protecting performance from the hazardous work environment factors; and work clothes' designs that provides workers with maximized clothing comfort and wearer mobility for bending or tilting postures of upper, lower and lateral body parts defined in the study.

• 한국식품조리과학회지
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• 제32권6호
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• pp.762-772
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• 2016

Purpose: Adolescence is a critical period for growth and development; hence, knowledge about good food habits is essential amongst children. This study was conducted to investigate prevalence of awareness among food sellers, which could probably influence children's health and perceptions on food around schools towards adulterated food management beliefs, competencies, and food safety practices. Methods: Data was collected from 195 dealers around 25 elementary, middle and high schools in Daegu and Gyeongbuk provinces using a self-administered questionnaire in July and August, 2015. The data was analyzed using frequency analysis, one-way analysis of variance, $x^2$-test, factor analysis, and reliability analysis by SPSS Statistics (ver. 23.0). Results: A total of 121 people (62.1%) reported satisfaction of providing information and education on adulterated food. The perception of hazardous substances was found to be related to food poisoning bacteria and viruses (65.6%), heavy metals (42.1%), environmental hormones (36.4%), residual pesticides (27.2%), and irradiated food (26.7%). The perceived score on hygiene practices for processed food seller was $4.04{\pm}0.56/5.00$ and for cooked food seller was $4.09{\pm}0.45$. The capacity of adulterated food management practice of food sellers was significantly correlated with food knowledge on adulteration and public relation capacity, necessity of adulterated food management, and perception of hygiene practices (p<0.01). Similarly, knowledge and public relation capacity were significantly different according to ages (p<0.01). The perception of the necessity of adulterated food management was significantly different according to education levels (p<0.05), and the evaluation of hygiene practices was significantly different according to age (p<0.01). Conclusion: In order to solve the problem of adulterated food, which is one of the four social evils, and to strengthen the capacity of children to solve social problems, various practices like campaign on health promotion, goof food habits, education, and adulterated food management, should be actively promoted not only for children but also for food sellers around the schools.

• 한국자동차공학회논문집
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• 제17권3호
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• pp.81-89
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• 2009

In this experimental study, the effects of clean alternative fuels compatible with diesel combustion on nano-sized particle emission characteristics were investigated in a 0.5L auto-ignited single-cylinder engine with a compression ratio of 15. Because the number concentration of nano-sized particles emitted by automotive engine, that are suspected of being hazardous to human health and environment, might increase with engine fuel considerably and recently attracted attention. So a ultra-low sulfur diesel(ULSD), BD100(100% bio-diesel) and Di-Methyl Ether(DME) fuels used for this study. And, as a particle measuring instrument, a fast-response particle spectrometer (DMS 500) with heated sample line was used for continuous measurement of the particle size and number distribution in the size range of 5 to 1000nm (aerodynamic diameter). As this research results, we found that this measurements involving the large proportion of particles under size order of 300nm and number concentration of $4{\times}10^9$ allowed a single or bi-modal distribution to be found at different engine load conditions. Also the influence of oxygen content in fuel and the catalyst could be a dominant factor in controlling the nano-sized particle emissions in auto-ignited engine.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2602-2608
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• 2015

본 연구는 고춧가루의 HACCP(Hazard Analysis Critical Control Point) 시스템 적용에 필요한 미생물학적 위해 요소분석을 위한 목적으로 2014년 1월 10일~2014년 6월 13일까지 충주시 동량면 소재에 있는 용금농산에서 수행하였다. 고춧가루 제품의 모든 공정 단계들을 파악하여 공정흐름도를 작성하였고 미생물학적 위해를 제어할 수 있는 자외선살균공정에서 살균 시간을 변화시키면서 미생물의 변화를 시험한 결과 자외선 등 $20W{\times}12EA$, 살균 시간은 $63{\pm}3$초를 한계기준으로 결정하였다. 자외선살균 후에는 위해 미생물 검사 결과는 안전하나 제조환경과 작업자의 미생물 검사 결과 주기적인 세척 및 소독을 실시하여 미생물학적 위해를 감소시키고 작업자 위생교육 등을 통하여 개인위생을 준수해야 할 것으로 판단된다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 춘계학술대회 논문집
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• pp.189-195
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• 2004

최근 우리나라의 해상에서는 육상과 섬 또는 섬과 섬을 연결하는 해상교량이 건설 중이거나 건설 예정이다. 선박의 통항로에 해상교량이 설치되면 선박통항의 안전성은 당연히 위해가 되지만, 국가 및 지역의 경제발전을 위해서 설치가 불가피한 경우도 있다. 이러한 선박통항 안전성과 지역 경제성 간에 트레이트 오프(trade off) 관계가 있는 해상교량을 설치하기 위해서는, 선박통항 안전성 면에서 고려되어야 할 요소를 해상교통공학적인 측면에서 조사ㆍ검토하고, 그 요소들을 평가하여 교통 흐름을 원활하게 하고 해역의 안전을 보장하기 위한 것이 이 연구의 목적이다. 주교각폭이 넓은 교량을 설치하면 선박의 통항 안전성 측면에서는 유리하겠지만, 지형적인 영향이나 경제성 측면 때문에 충분한 항로폭을 확보할 수 없는 경우도 있을 수 있다. 따라서 이 논문에서는 해상교통류 시뮬레이션 기법을 이용하여 선박통항의 안전성을 확보하기 위한 통항량 규제와 같은 대안을 검토한다.

• 한국환경보건학회지
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• 제30권3호
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• pp.272-282
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• 2004

Stress is a primary health promotion issue in worksite research because psychological distress is closely related not only to workers　 health status but also to their job performance. This study identified the work environment and work condition factors affecting workers　 stress symptoms among the Korean manufacturing factory workers. A total of 7,818 factory workers employed in 1,562 manufacturing companies participated in the Korean nation-wide occupational health survey conducted by the Korean Occupational Safety and Health Agency in 2003. Participants were selected by the stratified proportional sampling process by standardized industry classification, company size, and locations. Trained interviewers visited the target companies and interviewed the factory workers randomly selected in each company. Work environments included physical work environments (temperature, noise, hazardous organic compounds, and so on) and psychological work environments (job demands, job control, and social support at work), and work conditions included daily working hour, rest time, and so on. Men were 71.5% and the mean age was 34.0 years old. The average working period in the present company was 6.9 years. The average stress score was 26.2 under the perfect score, 50, which means the moderate level of stress. Perceived stress had significant correlations with young age, poor physical work environment, high fatigue, bad perceived health status, and high job demands in Pearson's simple correlation analysis. Perceived health status and perceived fatigue explained 21% variance of stress symptoms and the work environment factor explained 4.8% of that; however, work condition did not have the sufficient effect. In particular, psychosocial work environment variables (job demand, job control, and social support at work) had a clear effect on stress symptoms rather than the physical work environments. Poor perceived health status, severe perceived fatigue, poor physical work environment, high job demands, low social support, heavy alcohol consumption and little exercise were significantly related to high stress symptoms in the Korean manufacturing workers.