• 한국산업보건학회지
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• 제32권4호
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• pp.287-301
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• 2022

Objectives: This study compared the characteristics of the work environment between agricultural and general workers and analyzed the effects of agricultural working characteristics on work-related health problems. Methods: The participants of this study were 2,347 agricultural workers and 48,042 general workers who were selected by applying standardized weights to the raw data of 50,538 respondents from the 6th Korean Working Condition Survey (KWCS). Variables applicable to both worker groups and related to exposure to hazardous risk factors in the working environment, working hours and intensity of work, health problems and work-related status, and satisfaction with the work environment were selected. Chi-square tests and independent sample t-tests were performed to evaluate the differences in the variables between the two groups. Multivariate logistic regression analysis was conducted to analyze the effects of work environment characteristics on work-related health problems. Results: Compared to general workers, agricultural workers were more exposed to hazardous environments, irregular work patterns such as working on Saturday/Sunday, and short repetitive tasks. They reported more work-related and general health problems, including back pain, upper extremity muscle pain, lower extremity muscle pain, and general fatigue. Agricultural workers showed lower satisfaction with their work environment than general workers. Factors affecting one or more work-related health problems included gender, working years, hazardous factors, irregular work pattern, working hours, and labor intensity. Conclusions: Our findings showed that agricultural workers were relatively more vulnerable to safety issues compared to other occupational groups. Therefore, it is necessary to establish standardized safety and health standards and strengthen systematic safety and health management policies and services for agriculture.

• 한국입자에어로졸학회지
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• 제4권1호
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• pp.9-20
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• 2008

The effect of light intensity on the ozone formation and the aerosol number concentration during the photochemical reactions of ambient air was investigated in an indoor smog chamber. The smog chamber consists of a housing, 64 blacklights, and a $2.5-m^3$ reaction bag made of Teflon film. The bag was filled with the unfiltered ambient air in Seoul from January 10 to March 18, 2002. In this work, the photolysis rate of $NO_2$, $k_1$ was used as an index of light intensity. Three levels of light intensity were controlled by changing the number of blacklights turned on among 64 blacklights: $0.29min^{-1}$ (50%), $0.44min^{-1}$ (75%), $0.57min^{-1}$ (100%). The ozone concentration increased rapidly within 10 minutes after irradiation irrespective of light intensity, thereafter it increased linearly during the irradiation. The ozone production rate seems to be dependent on both the light intensity and the quality of ambient air introduced into the reaction bag. The change in aerosol number concentration also depended on both the light intensity and the ambient air quality, especially aerosol size distribution. Based on the initial ambient aerosol size distributions, the photochemical potential for aerosol formation and growth is classified into two cases. One is the case showing aerosol formation and growth processes, and the other is the case showing no apparent change in particle size distribution.

• 벤처창업연구
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• 제11권3호
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• pp.37-48
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• 2016

본 연구는 우리나라 벤처기업들의 국제화에 영향을 미치는 요인과, 국제화 수준이 기업의 경영성과에 영향을 주는지를 분석하기 위하여 "벤처기업실태조사" 자료 중 1,970개 벤처기업 자료를 활용하여 실증적으로 분석하였다. 경영자의 특성 중 연령은 유의한 영향을 주지 않는 반면, 경영자의 학력과 과거 업무 경험은 매우 유의하게 벤처기업의 국제화 수준에 영향을 주었는데, 박사학위를 보유한 경우와 과거 마케팅 분야의 업무 경험을 보유한 경우에 다른 경우보다 수출집중도가 높게 나타났다. 기업 특성의 경우, 기업의 기술수준은 기업 국제화 수준에 미치는 영향이 유의하지 않았지만, 외주생산을 하는 경우에 그렇지 않은 기업보다 수출집중도가 유의하게 높았고, 업력이 증가할수록 기업의 국제화 수준이 유의하게 낮았다. 또한, 국내시장의 경쟁 수준은 벤처기업의 국제화 수준에 영향을 주지 않은 반면, 수출지역 및 직접진출지역의 수가 늘어날수록 국제화수준은 높아지고, 그 수출지역의 수가 더욱 큰 영향을 미쳤다. 한편, 국제화 수준은 일반적으로 벤처 기업의 영업이익율에 유의한 영향을 주지 못하였지만, 창업후 10년 이후의 기업군에서는 매우 유의하게 긍정적 영향을 미쳤다. 본 연구의 결과는, 국제화에 있어 벤처기업 경영자의 교육과 업무경험 뿐만 아니라, 해외시장에 진출하는 기업들의 전략이 중요하다는 것을 시사한다.

• Journal of information and communication convergence engineering
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• 제1권4호
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• pp.228-232
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• 2003

The previous design work for very large final amplifier pumped by electron beam module was described from the point of view of energy characteristics. In this work, the design problems for phase front distortion, ASE, and gain control in large aperture amplifier are presented in detail.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.201-210
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• 2003

In this paper, we propose a new binocular stereo correspondence method by maximizing a fitness formulated by integrating two constraints of edge similarity and disparity smoothness simultaneously. The proposed stereopsis focusing to measure distances to leading vehicles on roads uses intensity gradients as matching attribute. In contrast to the previous work of area-based stereo matching, in which matching unit is a pixel, the matching unit of the proposed method becomes an area itself which is obtained by selecting a series of pixels enclosed by two pixels on the left and right boundaries of an object. This approach allows us to cope with real-time processing and to avoid window size selection problems arising from conventional area-based stereo.

• 분석과학
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• 제17권3호
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• pp.271-277
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• 2004

The aim of this study was to investigate questioned documents written with blue or black ballpoint pen on paper by nondestructive technique. In this work, 21 blue and 22 black ballpoint pen inks which were purchased on different brands were analyzed by using Microspectrophotometry (MSP). The reflectance spectra were obtained from these ink samples and their shapes and the wavelength of the maximum intensity were compared. In the blue and black ballpoint pen inks, the discriminating powers (DP) were 0.85 and 0.61, respectively. The changes of the reflectance intensity at their wavelength of maximum intensity and their shapes appeared according to the exposure time to sunshine in a laboratory, especially in the blue ballpoint pen inks. Therefore it is possible to distinguish ink entries on the same paper with the relative age in case of questioned letters written with blue ballpoint pen.

• Journal of Biosystems Engineering
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• 제20권2호
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• pp.117-126
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• 1995

High level of tractor noise may reduce operator's work performance and cause a hearing problem. This study was carried out to investigate the cab noise of a selected agricultural tractor. The noise was measured and analyzed in terms of sound and sound intensity levels. Form the results it was known that a structure-born noise was induced from the feet-rest and rear floor panel of the cab. The air-borne noise caused mainly by the engine was transmitted into the operator's position through the small openings of cab structures in the operator's lower front area.

• 한국대기환경학회지
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• 제15권1호
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• pp.1-11
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• 1999

In this work, a theoretical model has been formulated which allows the study of the scavenging efficiencies of aerosol particles by the rain drops. Aerosol particles are scavenged by the simultaneous brownian diffusion, interception and inertial impaction force. In addition the calculations based on the collision efficiency model are carried out for the collision of aerosol particles with diameter range 0.01~30 $mu extrm{m}$ and rain drops with diameter 0.02$\times$$2^{n/3}$(n=1, 2, …, 17)cm. The results indicate that: (1) the below-cloud scavenging affects mainly the coarse particles (＞3 ${\mu}{\textrm}{m}$), the fine particles remaining almost unchanged; (2) the scavenging efficiencies by below-cloud in the heavy rain (rain intensity, 10 mm/hr) surpass the efficiency found in the drizzle rain (rain intensity, 1 mm/hr).

• Journal of Korean Society for Atmospheric Environment
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• 제17권E3호
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• pp.117-124
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• 2001

The present paper examined the kinetics of photocatalytic degradation of volatile organic compounds (VOCs) including gaseous trichloroethylene (TCE) and acetone. In this study, we examined the effects of the initial concentration of VOCs and the light intensity of ultra-violet (UV). A batch photo-reactor was specifically designed for this work. The photocatalytic degradation rate increased with the initial concentration of VOCs but remained almost constant beyond a certain concentration. It matched well with the Langmuir-Hinshelwood (L-H) kinetic model. When the effect of light intensity was concerned, it was found that photocatalytic degradation occurs in two regimes with respect to light intensity.

• 한국안전학회지
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• 제31권2호
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• pp.98-103
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• 2016

The goals of this study were to investigate some significant factors to judge level of safety at urban railway construction field and to analyze degree of risk by work classification. Currently, there are lots of construction fields for the urban railway for national transportation, and our government also planned constructing more urban railway in near future. However, most of the researches on safety neglected the degree of risk factors on the urban railway construction field. Safety managers participated in the brainstorming session for deriving decision criteria of the degree of risk (i.e., significant factors). Then, they were asked to answer a structured questionnaire which was developed for deriving most important factors. Finally, the analytic hierarchy process (AHP) was used to analyze level of risk by work classification. The following results were obtained. First, total twelve factors judging degree of risk were found in the brainstorming session. Second, the questionnaire showed four significant factors, including adjacency of obstacle, intensity of work, unsafe condition and work space. Third, the results of AHP showed civil work is the most dangerous work among 6 work types. The results could be used to give the safety management priority on accident prevention efforts among several hazards and to reduce degree of risk in construction field of the urban railway.