• Physical Therapy Korea
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• v.17 no.4
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• pp.61-68
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• 2010

The purpose of this study was to investigate the effects of a workplace-based work-conditioning program (WCP) on the management of work-related musculoskeletal disorders (WRMDs) in an automobile-parts manufacturing company. In total, 1,110 subjects with WRMDs participated in workplace-based WCP emphasizing function-centered management and ergonomics. We investigated the incidence of WRMDs variables (number of persons diagnosed with industrial accident-related WHMDs, number of cases of WRMD) and financial benefits (cost of workers' compensation insurance and lost work days related to WRMDs) per year before and after WCP. Additionally, we compared self-reported pain intensity and functional disability in subjects with musculoskeletal pain before and after the WCP. Pain intensity was measured using a visual analog scale (VAS), and functional disability was measured by the neck disability index (NDI) and the Oswestry disability Index (ODI). The number of person diagnosed with industrial accident-related WRMDs, the number of cases of WRMD, the cost of workers' compensation insurance and lost work days related to WRMDs per year decreased by 51%, 37%, 34%, and 47%, respectively, and VAS, NDI, and ODI scores decreased significantly after implementation of WCP (p<.05). Thus, the results of the present study suggest that function-centered, workplace-based WCP was effective in managing WRMDs at an automobile-parts manufacturing company.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.446-455
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• 2022

This study investigated work experience of firefighters and risk factors for their depression during COVID-19 pandemic. We analyzed data of 53,557 firefighters who participated in the online mental health status survey. Data included experiences of COVID-19 infection, experience of COVID-19 response work, fear of social stigma, and anxiety and depression symptoms. Results showed that 45.76% of participants had experience of COVID-19 response work. Emergency job group had the highest percentage of COVID-19 related work and the greater intensity of the work and fear of social stigma than those of other job groups. Hierarchical multiple regression showed that co-workers' infection, COVID-19 related work intensity and fear of social stigma were significantly associated to the severity of depression. The findings in this study demonstrated COVID-19 related work experience can link to the development of depression in firefighters. Effort to reduce COVID-19 related work intensity and fear of social stigma could help prevent depression among firefighters.

• Journal of Preventive Medicine and Public Health
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• v.29 no.1 s.52
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• pp.91-102
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• 1996

Low back pain patients and controls of shipyard workers were surveyed between June 1995 and September 1995 to identify risk factors of industrial low back pain. The patients were 17 male workers who had got medical treatment for over 3 days because of industrial back pain. Controls were 51 male workers who had not have musculoskeletal disorder for one year before the survey. By univariate analysis, the workers who did overtime work 4 times or more for the last 2 weeks showed odds ratio of 3.67 on low back pain with the workers who did less overtime work. Carrying heavy materials was also associated with the low back pain and the odds ratio increased with the increase of carrying weight. Work space and work posture were not associated with the low back pain significantly. The welder had higher odds ratio than the other workers on low back pain. The duration of employment and job satisfaction did not affect the risk of low back pain. Multiple logistic regression analysis showed that frequency of overtime work for the last 2 weeks and carrying heavy materials among the risk factors were associated significantly with the low back pain. We found that important risk factors of low back pain of shipyard workers are work intensity factors such as overtime work and carrying heavy weight.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.822-831
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• 2011

This study was to examine factors related to depression of female labor workers. In order to identify health promotion strategies and intervention program to reduce depression of female labor workers. The participants were 176 female workers of manufacturing industries. Data were collected using a structured questionnaire that consisted of personal characteristics, duty related, work related characteristics and depression. Using a SPSS/WIN 17.0 Program, descriptive statistics, $x^2$-test, ANOVA and Stepwise Multiple Regression procedures were employed. As follows on the results; In Correlation analysis, work intensity, work concentration, vibration, work difficulty and job stress were positively correlated with depression. In multiple Regression, work intensity and work difficulty were significantly explained by depression. Given the findings, Do nevertheless support the need to develop effective depression intervention programs to reduce factors which work related condition and depression.

• Journal of Welding and Joining
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• v.1 no.1
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• pp.37-46
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• 1983

This paper describes a study of fillet welded joint stressed perpendicular to the weld line. The finite element method was used to determine the stress intensity factor for cruciform joint at weld toe and root cracks according to variation of H/Tp, weld angle and main plate thickness. But, in this study, weld angle was fixed at 45.deg., since the variation of weld angle affect the stress intensity factor little, also main plate thickness was fixed. Pulsating tension fatigue test was done at the second phase of experiment. The work using the concepts of the fracture mechanics on the stable crack growth, was in the correlation of the experimental fatigue stress-life behavior because the fatigue behaviors of various joint geometries are related to the stress intensity factors calculated by F.E.M. analysis. Main results obtained are summarized as follows. 1) According to the propagation of toe crack, the variation of the stress intensity factor at root crack is obvious as H/Tp is smaller. 2) According to the propagation of root cracks, the change of the stress intensity factor of the toe is very large with propagation of root crack. 3) The calculation formula of the stress intensity factor of crack propagation at the root crack was obtained. 4) The calculation formula of the stress intensity factor at the toe cracks was obtained in similar manner. 5) From the results of experiment, the velocity of fatigue crack propagation at the weld toe and root was estimated.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.6
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• pp.77-86
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• 2016

Due to aging of the rural and mountain populations the labor force is reduced. However work intensity continues to increase, thus, there is a need to improve the current effectiveness of forest operations. This study compared and analyzed the Operation productivity and efficiency of planting containerized seedlings using a battery-powered planting auger and a mattock. Growth was also investigated by looking into the initial growth increments in the planted seedlings. Tasks were investigated by analyzing the process and operation time needed to plant 1 containerized seedling using a planting auger and a mattock. The time spent on the various elements of the planting process was measured with a stopwatch but observations were done continuously. Result of the study shows that with the use of a lightweight planting auger the average time spent to plant a containerized seedling is 18.61 seconds while with the use of a mattock it took an average of 26.96 seconds which clearly demonstrates that the planting auger is more efficient in terms of working hours. Working intensity was also analyzed with the use of a portable heart rate monitor (Polar V800). The average increase in heart rate and work intensity index were analyzed for one planting cycle. It was observed that when using the lightweight planting auger, there was a 46.51% increase in the average heart rate while a 74.67% increase in heart rate when the mattock was used which shows that there is a significant increase in heart rate when mattock is used. In addition, work intensity index was observed to be 29.95% and 47.83% when the planting auger and mattock were used respectively. With the continuous use, work intensity index is significantly higher with the use of the mattock as compared to that of the lightweight planting auger. There were no significant differences on the growth increment of seedlings planted using the different tools until a year after planting, however differences in growth increment were observed after a year. A difference of 15.1 cm in height and 3.41 mm in diameter was observed which shows that the use of lightweight planting auger is excellent for planting containerized seedlings.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.97-103
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• 2013

The purpose of this study was to verify the change in temperature humidity perspiration of fire suit when applying phased intensive exercises to fire fighter wearing fire suit. For this study, three male fire fighters took basic physical test and performed 10 minute phased intensive exercises -exercise intensity I (30%VO2max), exercise intensity II (45%VO2max), exercise intensity III (60%VO2max) based on maximum oxygen consumption (VO2max)- wearing fire suit (helmet, boots, air respirator) in treadmill and took a rest. The result of study shows that the temperature in the suit elevated during stabilization period after each exercise intensity, humidity elevated as exercise intensity increased, perspiration elevated as exercise intensity increased. This study indirectly ascertained the fire suit's physiological change in fire fighters during field activities.

• Structural Engineering and Mechanics
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• v.3 no.6
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• pp.541-553
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• 1995

The determination of the stress intensity factors is investigated by using the surface integral defined around the crack tip of the structure. In this work, the integral method is derived naturally from the standard path integral J. But the use of the surface integral is also extended to the case where body forces act. Computer program for obtaining the stress intensity factors $K_I$ and $K_{II}$ is developed, which prepares input variables from the result of the conventional finite element analysis. This paper provides a parabolic smooth curve function. By the use of the function and conventional element meshes in which the aspect ratio (element length at the crack tip/crack length) is about 25 percent, relatively accurate $K_I$ and K_{II}$ values can be obtained for the outer integral radius ranging from 1/3 to 1 of the crack length and for inner one zero.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.10
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• pp.1096-1100
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• 2012

In the phase-shift measurement method, the distance light travels can be obtained based on the phase difference between the reference signal and the measured signal. When the object having various colors is measured, the intensity of the measured signal much varies even at the same distance, and it causes different phase delay due to wide dynamic range input to a signal processing circuit. In this work, an measured intensity control method is proposed to solve this phase delay problem.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.569-578
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• 1998

The mode I and II stress intensity factors have been calculated theoretically for the cracked plate reinforced with a plate by symmetric spot welding under remote mixed mode loading. This is the extension of authors' previous work for the reinforced cracked plate under remote normal stress. Regardless of loading types, the reinforcement effect gets better as one joining spot is closer to the crack tip and the others are closer to the crack surface, and optimum number of the joining spots can be existed. For the present model, the remote loading parallel to crack surface produces the mode I stress intensity factor.