• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.96-97
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• 2017

Performances such as retention, setting time and strength generation of mortar with phosphate-introduced chemical admixture, domestic and foreign admixtures are evaluated to find one that meets over 3 hours retention in extremly hot weather condition in this study.

• Bulletin of the Korean Chemical Society
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• 제7권4호
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• pp.271-275
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• 1986

The Smoluchowski equation with a step potential is solved in one-dimensional case and three-dimensional case with spherical symmetry. Exact analytic expressions for the solution and the remaining probability are obtained in one-dimensional case for the reflecting boundary condition and the long time behavior of the remaining probability is compared with the earlier work. In three-dimensional case, only the long time behavior is evaluated. More general case with the radiation boundary condition is also investigated and the results are shown to approach correct limits of the reflecting boundary condition.

• 한국의류학회지
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• 제28권5호
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• pp.713-722
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• 2004

This study examined the effects of two kinds of functional sun hats through a head-manikin test and a climatic chamber trial for farm workers in summer. Experiment was composed of four conditions. The first condition was the condition without any hat (Control). The second was the condition with a sun hat on the market (Hat A). The third was the condition with a functional sun hat made of reflective fabric (Hat B). The last was the condition with a functional sun hat having a ventilating structure as well as reflective fabric (Hat C). For the subjects in the climatic chamber trials, 12 healthy males volunteered. Air temperature, relative humidity and globe temperature in the chamber was maintained at $33{\pm}0.5^{\circ}C,\;65{\pm}5%RH\;and\;39{\pm}1^{\circ}C\;(WBGT\;33^{\circ}C)$. Subjects did a simulated red pepper-work (50-min work and 10-min rest, twice repetition) for 120 min. As the result of head-manikin test, the surface temperature on middle of back-neck was the lowest in Hat B of four conditions and the surface temperature on top of head was the lowest in Hat C. As the result of climatic chamber trials, there were apparent differences between with (Hat A, Hat B, Hat C) and without a sun hat (Control). In rectal temperature ($T_{re}$), mean skin temperature ($\={T}_{sk}$), heart rate (HR), total sweat rate (TSR), The physiological heat strain was less in the condition with hats than in the condition without a sun hat. As the increasing rate in Tre, Hat B is the most effective hat for alleviation heat strain. As the subjective responses, Hat B was the most effective hat for thermal comfort even though the difference was not significant. Hat C was less effective than Hat B and the reason might be the increase of weight due to inserting the ventilating structure.

• Tribology and Lubricants
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• 제18권4호
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• pp.285-290
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• 2002

Integrated condition monitoring is required to monitor effectively the machine conditions since machine failures could not be monitored accurately by any single measurement parameter. Application of various condition monitoring techniques is therefore preferred in many cases in order to diagnosis the machine condition. However it inevitably requires lots of maintenance cost and sometimes it could be proved to over-maintenance unnecessarily. This could happen especially when one measurement parameter closely correlates to another. Therefore correlation analysis of various monitoring parameters has to be performed to improve the reliability of diagnosis. In this work, Pearson correlation coefficient was used to analyze the correlation between condition monitoring parameters of an over-loaded machine system where the vibration, wear and temperature were monitored simultaneously. The result showed that Pearson correlation coefficient could be regarded as a good measure for evaluating the availability of condition monitoring technology.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.252-259
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• 2001

Integrated condition monitoring is required to monitor effectively the machine conditions since machine failures could not be monitored accurately by any single measurement parameter. Application of various condition monitoring techniques is therefore preferred in many cases in order to diagnosis the machine condition. However it inevitably requires lots of maintenance cost and sometimes it could be proved to over-maintenance unnecessarily. This could happen especially when one measurement parameter closely correlates to another. Therefore correlation analysis of various monitoring parameters has to be performed to improve the reliability of diagnosis. In this work, Pearson correlation coefficient was used to analyze the correlation between condition monitoring parameters of an over-loaded machine system where the vibration, wear and temperature were monitored simultaneously. The result showed that Pearson correlation coefficient could be regarded as a good measure for evaluating the availability of condition monitoring technology.

• 한국직업건강간호학회지
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• 제20권2호
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• pp.119-129
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• 2011

Purpose: This study firstly examined the pattern and prevalence of drinking. Secondly, we investigated the association between various psychosocial work environment and problem drinking among Korean male workers in different age groups. Methods: The study sample was a weighted population of 3,289 (3,289 survey samples) men aged 20 to 64 years who responded to the 2006 Korean Working Condition Survey. Social support from colleague and supervisor, work autonomy, psychological wellbeing at work, and intellectual and emotional work demand were assessed. Results: After considering sociodemographic factors, smoking, occupational characteristics and other psychosocial work environment factors, problem drinking was associated with "intellectual work demand" for the 20~34 year old group. Social support from colleague and supervisor was significantly associated with problem drinking in the 35~49 year old group. For the 50~64 year old group, problem drinking was associated with 'work autonomy'. Conclusion: The present study clarified that certain psychosocial work environmental factors relate to problem drinking, and the association varies among different age groups.

• 대한기계학회논문집A
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• 제20권9호
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• pp.2792-2799
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• 1996

It was shown in the previous study that the numerically derived elastic work factor for CLS specimen was independent of fiber direction for a unidirectional case. Also, it was proposed the elastic work factor could be used to determine energy release rate from a single test record. In the present study, elastic work factor was derived from a simple beam theory to investigate its dependence on material property and geometric condition. Also, the elastic work factor of CLS specimen was applied experimentally to determine critical energy release rate in order to prove its validity determining critical energy release rate from a single specimen. For this purpose, critical energy release rate determined using the elastic work factor was compared with that determined by the compliance method. The results showed that while elastic work factor is affected by $t_2/t_1$ and $L_2/L_1$ it is independent of fiber angle for a unidirectional case. It was also found that critical energy release rates determined by both methods are comparable each other, thus elastic work factor approach can be used to determine energy release rate from a single test specimen.

• Safety and Health at Work
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• 제11권1호
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• pp.1-9
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• 2020

Background: As the impact of climate change intensifies, exposure to heat stress will grow, leading to a loss of work capacity for vulnerable occupations and affecting individual labor decisions. This study estimates the future work capacity under the Representative Concentration Pathways 8.5 scenario and discusses its regional impacts on the occupational structure in the Republic of Korea. Methods: The data utilized for this study constitute the local wet bulb globe temperature from the Korea Meteorological Administration and information from the Korean Working Condition Survey from the Occupational Safety and Health Research Institute of Korea. Using these data, we classify the occupations vulnerable to heat stress and estimate future changes in work capacity at the local scale, considering the occupational structure. We then identify the spatial cluster of diminishing work capacity using exploratory spatial data analysis. Results: Our findings indicate that 52 occupations are at risk of heat stress, including machine operators and elementary laborers working in the construction, welding, metal, and mining industries. Moreover, spatial clusters with diminished work capacity appear in southwest Korea. Conclusion: Although previous studies investigated the work capacity associated with heat stress in terms of climatic impact, this study quantifies the local impacts due to the global risk of climate change. The results suggest the need for mainstreaming an adaptation policy related to work capacity in regional development strategies.

• 지식경영연구
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• 제14권2호
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• pp.49-69
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• 2013

In this study, we examined how the psychological safety influence expected image outcomes(image gain, image risk) and how expected image outcomes impact one's involvement in creative work. And, we examined the relationship between creative work involvement and job performance. We also investigated mediating role of expected image outcomes between psychological safety and creative work involvement. Survey data was collected from 271 employees working in a South Korea. The results of structural equation modeling using LISREL 8.50 indicate that psychological safety was positively related to expected image gain, but not significantly related to expected image risk. The result also expected image gain was positively related to creative work involvement, contrary to prediction of hypothesis 2-2, expected image risk was positively associated with creative work involvement. In addition, creative work involvement has positive effect on job performance. Finally, the relationship of expected image outcomes about psychological safety and creative work involvement was mediated by expected image gain partially. We extended the literature and contributed better understanding of the creativity research by answering calls for further research on involvement in creative work rather then the outcome of the creative process.

• 보건의료산업학회지
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• 제9권1호
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• pp.41-55
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• 2015

Working the night-shift and long working hours may be linked to insomnia. The purpose of this study is to determine the association between night-shift work and long working-hours with regard to subjective insomnia in Korean workers. This study was based on the Third Korean Working Condition Survey (KWCS) conducted on workers in 2011. The total number of individuals included in the analysis was 34,708 workers. Adjusted odd ratios showed statistically effective associations to insomnia. For night-shift work, the results were 2.71 (1.53 - 4.82) for night shift work by experts and managers, 2.95 (2.11 - 4.11) for night-shift work by officers, and 3.90 (2.05 - 7.42) for night-shift work by engineers compared with day duty. For long working hours, the scores were 2.43 (1.68-3.51) for >52 working hours by officers, 1.72 (1.15 - 2.58) for those in sales and service compared to ${\leq}40$ working hours. We suggest the need for Korean workers to target specific groups when creating policies related to reasonable environmental conditions.