• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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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.

• Particle and aerosol research
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• v.4 no.1
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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.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.3
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• pp.37-48
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• 2016

The purpose of this study is to investigate the factors that affect the degree of export intensity of Korean venture businesses, and to analyze the effect of export intensity on corporate performance. We use 1,970 firm data (from Venture Business Survey by Small & Medium Business Administration) and analyze the possible factors of the CEO characteristics, the corporate characteristics, and the environmental factors. Our analysis shows that Korean venture business' CEO characteristics, such as his/her doctoral degree and marketing work experiences, increase their export intensity statistically significantly, while their age does not. In addition, the companies who outsource their products have a higher export intensity, and, as the firm age increases, the export intensity decreases significantly. It is also analyzed that, as the number of export regions or FDI regions increases, their export intensity goes higher. However, firms' higher level of internationalization does not bring higher performance of the venture firms, while it does significantly for the venture firms that are older than 10 years. The result implies that CEO's education or work experiences and strategic approaches are important for corporate globalization, and that it takes time for globalizing venture firms to be able to garner profits from their global investments.

• Journal of information and communication convergence engineering
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• v.1 no.4
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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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.

• Analytical Science and Technology
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• v.17 no.3
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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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• v.20 no.2
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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.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.1
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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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• v.17 no.E3
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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.

• Journal of the Korean Society of Safety
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• v.31 no.2
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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.