• Journal of Korean Society of Disaster and Security
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• v.14 no.4
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• pp.1-7
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• 2021

Although the working environment has changed significantly compared to the past, such as the implementation of the five-day work week and the aging of the population, it is not reflected in the current industrial accident index calculation such as frequency rate, severity rate, and safe T-score. In this study, statistical data were used to understand time-series trends such as increase in life expectancy, working age, shortening of working hours, and average age of death by accident. As a result of time series trend analysis of statistical data, life expectancy increased to 83.3 years, and the legal working age was raised to 65 years due to the aging of the population. Also, with the advent of the 5-day work week since 2001, the average annual working hours decreased to 2008.1 hours. It can be confirmed through statistical data that these phenomena are applied to the current working environment due to a complex action, and these environmental changes affect the calculation results of the industrial accident index.

• Journal of Fashion Business
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• v.14 no.2
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• pp.110-126
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• 2010

The purpose of this study is for finding the demand and perception about color situation of the working environment including work places and working clothes according to the workers in the machinery automobile shipbuilding companies. Data were collected by questionnaire surveying 679 workers. The collected data were analysed through frequency, mean, cross tabs analysis by SPSS for windows 17.0. As a result, most of the workers responded that they were not satisfied with the current working environment and the colors of their working clothes. However, the workers held a perception that influence that the colors of the working environment has on their psychology and safety or the colors' role was relatively significant. And they had a very positive expectation for the effect of the working clothing's color planning. The study would serve as the beneficial information for formulating the safer and more pleasant working environment in industrial work places as well as a basic material for the subsequent research on colors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.941-942
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• 2012

• Safety and Health at Work
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• v.9 no.4
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• pp.421-426
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• 2018

Background: The purpose of this study was to investigate the effect of shift work on occupational safety in various industrial sectors. The study analyzes the effects of shift work on the health of workers by considering factors such as the workplace environment and welfare. Methods: Focusing on the $4^{th}$ Korean Working Conditions Survey, this study used an ordinary least-square multiple regression analysis. The dependent variable was the annual frequency of injuries reported by workers. Independent variables were categorized as demographic, shift work, workplace environment, and welfare variables. The analysis was conducted on two levels: 1) Shift work and nonshift work groups were compared, and 2) Shift work was compared with fixed and rotating shifts. Results: For the entire group, age, a low level of education, work hours, and daily and dispatch work negatively impacted the frequency of injuries. Shift work was negatively affected by workplace environment and welfare factors. In the shift group, the frequency of injuries was lower than that of regular workers, and the higher the autonomy in the choice of work hours, the lower the frequency of injuries. Furthermore, shift workers in Korea have more extended work hours (49.25 h/week) than other workers (46.34 h/week). Conclusion: Overall, welfare factors such as workplace satisfaction and worke-life balance reduced the frequency of injuries. The effect of shift work was limited, but it was confirmed that shift worker autonomy could reduce the frequency of injuries.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1533-1542
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• 2003

In the present study, the characteristics of pressure oscillation and heat transfer performance in an oscillating capillary tube heat pipe were experimentally investigated with respect to the heat flux, the charging ratio of working fluid, and the inclination angle to the horizontal orientation. The experimental results showed that the frequency of pressure oscillation was between 0.1 Hz and 1.5 Hz at the charging ratio of 40 vol.%. The saturation pressure of working fluid in the oscillating capillary tube heat pipe increased as the heat flux was increased. Also, as the charging ratio of working fluid was increased, the amplitude of pressure oscillation increased. When the pressure waves were symmetric sinusoidal waves at the charging ratios of 40 vol.% and 60 vol.%, the heat transfer performance was improved. At the charging ratios of 20 vol.% and 80 vol.%, the waveforms of pressure oscillation were more complicated, and the heat transfer performance reduced. At the charging ratio of 40. vol.%, the heat transfer performance of the OCHP was at the best when the inclination angle was 90$^{\circ}$ the pressure wave was a sinusoidal waveform, the pressure difference was at the least, the oscillation amplitude was at the least, and the frequency of pressure oscillation was the highest.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.830-839
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• 1993

Agricultural hydraulic robot which was reported in Part Ⅰ had been developed . The robot satisfied performance to intend before development. For actual use, however, it have been necessary to reduce manipulator weigh and to simplify construction of hydraulic control valve. Then, working stress of manipulator link and pressure fluctuation of hydraulic circuit were measured. Step and frequency response tests were done subject to amplitude of reference voltage of 0.1 , 0.3 , 0.5 and 1.0v. and delivery pressure of 3.5 and 5.0MPa. Working stress were about 25% comparing with fatigue strength, Thus, mass of manipulator might be reduce to 30 %. In hydraulic control system, virtual natural frequency of 6.5Hz is produced from the combination of drain passage area shortage of servovalve. Further , because of passage area shortage , working pressure at both side of cylinder was acted on. This phenomenon prevent utilize effectively engine power. Then, control valve for new model was p oposed.

• The Journal of Korean Academic Society of Nursing Education
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• v.22 no.4
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• pp.485-494
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• 2016

Purpose: The present research is a descriptive study aimed at understanding clinical nurses' Video display terminal (VDT) syndrome and identifying the factors that affect their VDT syndrome. Methods: Data were collected from 239 clinical nurses working in two metropolitan cities. Research tools included subject's VDT syndrome assessing musculoskeletal, ophthalmic, dermal, psychiatric, and whole body syndromes. The data were analyzed using frequency analysis, average and standard deviation, t-test, One-way ANOVA, and multiple regression analysis with the SPSS/WIN 20.0 program. Results: The subjects' VDT syndrome score was 1.34 out of 5. There were significant differences in participating subjects' VDT syndrome, hospital's size, working unit, health status, diagnosis of illness, having an Order Communication System (OCS), having an Electronic Medical Record (EMR) System, continuous VDT working for more than one hour, break time during VDT use, VDT use time, comfort of the chair, adjustability of the height of the chair, size of the VDT's desk, distance between the monitor and the user's eyes, resolution of the monitor, and frequency of eye exercise during VDT use. According to the research, influencing factors on VDT syndrome in clinical nurses included size of the VDT's desk, frequency of eye exercise during VDT use, having an EMR system, break time during VDT use, diagnosis illness, and having an OCS' system. Conclusion: The findings from this study can be used as a basis for future VDT syndrome prevention education and programs for clinical nurses.

• Journal of Mechanical Science and Technology
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• v.19 no.9
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• pp.1790-1800
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• 2005

The examination on the operating mechanism of a pulsating heat pipe (PHP) using visualization revealed that the working fluid in the PHP oscillated to the axial direction by the contraction and expansion of vapor plugs. This contraction and expansion is due to the formation and extinction of bubbles in the evaporating and condensing section, respectively. In this paper, a theoretical model of PHP was presented. The theoretical model was based on the separated flow model with two liquid slugs and three vapor plugs. The results show that the diameter, surface tension and charge ratio of working fluid have significant effects on the performance of the PHP. The following conclusions were obtained. The periodic oscillations of liquid slugs and vapor plugs were obtained under specified parameters. When the hydraulic diameter of the PHP was increased to d=3mm, the frequency of oscillation decreased. By increasing the charging ratio from 40 to 60 by volume ratio, the pressure difference between the evaporating section and condensing section increased, the amplitude of oscillation reduced, and the oscillation frequency decreased. The working fluid with higher surface tension resulted in an increase in the amplitude and frequency of oscillation. Also the average temperature of vapor plugs decreased.

• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.581-587
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• 2014

In this study we included 298 working women in Kangwon province to investigate the life style and eating habits related to constipation. The subjects were divided into 3 groups according to Roman II criteria as follows : normal, mild constipation and constipation groups. For the result, 48.4%, 42.7%, 27.2% and 28.6% of the subjects had constipation in the order of 20's, 30's, 40's, and 50's, respectively. Constipation group had low frequency of bowel movement per week and irregular visit to toilet compared to normal and mild constipation groups. There were higher percentage of people with reading habit while sitting on a toilet, in the constipation group compare to other groups. Constipation groups had difficulty having bowel movement when sleeping outside of their home. There was a significant difference in water consumption per day among the 3 groups. But there was no significant difference in the amount of meals consumed and the number of meals with snacks per day. For the food frequency, there was lower frequency of yogurt and vegetables consumption in the constipation group. But there was no difference in how to eat fruits. From these results, we concluded that in order to treat the constipation, it is recommended to take enough water and dietary fiber, and to have physical activities for the working women.

• International Journal of Fluid Machinery and Systems
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• v.9 no.1
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• pp.39-46
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• 2016

A high frequency hydraulic rock drill drifter with sleeve valve is developed to use on arm of excavator. In order to ensure optimal working parameters of impact system for the new hydraulic rock drill drifter controlled by sleeve valve, the performance test system is built using the arm and the hydraulic source of excavator. The evaluation indexes are gained through measurement of working pressure, supply oil flow and stress wave. The relations of working parameters to impact system performance are analyzed. The result demonstrates that the maximum impact energy of the drill drifter is 98.34J with impact frequency of 71HZ. Optimal pressure of YZ45 rock drill is 12.8 MPa-13.6MPa, in which the energy efficiency reaches above 58.6%, and feature moment of energy distribution is more than 0.650.