• Korean Journal of Occupational Health Nursing
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• v.9 no.2
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• pp.110-120
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• 2000

The purpose of this study was to examine which factors affected the job stress of workers in the manufacturing industry. The subjects were 128 workers in automobile component manufacturing companies located in Kyonggi-do province. Data were collected through self-reporting technique for 8 days, October 24-31, 2000. The instrument to test the work related truss was NIOSH's Work-related Stress Inventory revised by Korea Occupational Safety and Health Association(KOSHA) in 1999. The collected data were analysed with SAS. and frequency, percentage, mean value, standard deviation, t-test, ANOVA. Scheffe's post hoc test and Pearson's Correlation Coefficients. The major findings were as follows: 1. Mean job stress score for the job-related stress was $2.6{\pm}0.5$ on the basis of 5.0 points. Job stress was significantly different according to gender. The stress by role conflict showed higher score than the stress by role ambiguity. 2. Discretionary power(freedom to determine) of workers was scored $2.6{\pm}0.7$ on the basis of 5.0 points. And it was significantly different according to gender, duration of work and shift experience. 3. The work environment scored $2.2{\pm}0.3$ on the basis of 3.0 points and significant difference according to gender, age, marital status, type of employment, type of service, and shift work. 4. Role ambiguity showed significant negatively correlate with job control(r=-.32, P=.000) and decision making(r=-.31, P=.000). And decision making showed positively correlated with job control(r=.62, P=.000), and role conflict(r=.26, P=.003).

• Journal of Biosystems Engineering
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• v.19 no.4
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• pp.291-300
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• 1994

It is desired to operate tractor engines at or near maximum torque much of the time in field operation to increase fuel efficiency. To do this it is necessary to reduce engine speed and to shift gears to higher ratios as frequently as possible. Because of load variations in most drawbar work and inconvenience in gear shift, however, gear-type transmission are usually set in one ratio at unnecessarily high engine speeds, and engine-torque variations are used to compensate for changes in drawbar load. As a result, the most of time the tractor is not operated efficiently in terms of fuel consumption and work output. The objective of this study was to develop an automatic control system which is able to operate a tractor equipped with gear transmission under the optimal condition in terms of fuel efficiency with automatic governor setting and gear shift. An indoor experimental test set which can be used to simulate tractor operation, control engine speed and transmission ratio was developed in the previous paper. In this paper, the performance of the optimal operation system is reported. Through a series of tests, it was found that the automatic control system for optimal operation of tractors with gear transmission had a satisfactory performance.

• Korean Journal of Occupational Health Nursing
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• v.29 no.4
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• pp.306-315
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• 2020

Purpose: This study was conducted to identify the effects of caffeine intake by shift workers on sleep, considering various variable related to the sleep health of shift workers. Methods: A descriptive survey study was conducted with 128 employees who worked shifts. Respondents were surveyed on their of caffeine intake behavior, schedule type, quality of sleep, health promotion behavior, and occupational stress. Differences in their quality of sleep were assessed using the t-test and analysis of variance, while factors influencing the effect of caffeine intake on the quality of sleep were analyzed using hierarchical logistic regression. Results: The average Pittsburgh Sleep Index, Korean Version score of those surveyed was 7.3±3.25, indicating that their quality of sleep was low. On the other hand, their aveage daily intake of caffeine was 1.6±0.99 cups (1 cup =150 mL) and 116.4±77.58 mg/dL of caffeine. When the various variables that could have affected the quality of sleep were corrected, an increase in the amount of caffeine consumed was found to lead to a decrease in the quality of sleep (p=.015). Conclusion: Caffeine intake by shift workers has a significant bearing on their quality of sleep; therefore, such intake should be adjusted to improve their sleep health.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.35-45
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• 2016

Melatonin hormone involved in human's circadian rhythm adjustment sensitively responds to light's specific short wavelength ratio. A shift worker's circadian rhythm disturbance and sleep disorder are caused by the existing lighting conditions, whose short wavelength ratio is fixed. The life pattern of a shift worker changes irregularly because of irregular working hours and the same lighting environment; thus, his/her concentration is reduced. For such a reason, negative effects ensue to the detriment of healthy everyday life, including a high risk of accidents or having unsound sleep after leaving work. A smartphone-based wavelength control LED lighting system that targets shift workers and that can easily measure and control lighting suitable for wake-sleep cycle, according to working hours and closing hours, is proposed in this paper. First, after the light characteristics of LED lighting that changes depending on light control ratio are measured through the color sensor installed on the smartphone and the externally-linked Mini-Spectrometer, they are stored in the database. Based on the stored optical characteristics data, the measurement module and light control module are implemented. Lighting is offered using a control ratio having the maximum rate of short wavelength in consideration of the target illuminance, classified according to work type by identifying working hours as time when waking is required for shift workers. After a shift work leaves work, the amount of lighting is varied, using a control ratio having a minimum short wavelength rate so that a shift worker can enter the sleep state naturally.

• Journal of the Korean Magnetic Resonance Society
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• v.28 no.2
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• pp.6-9
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• 2024

HscA is a Hsp70-type chaperone protein that plays an essential role to mediate the iron-sulfur (Fe-S) cluster biogenesis mechanism in Escherichia coli. Like other Hsp70 chaperones, HscA is composed of two domains: the nucleotide binding domain (NBD), which can hydrolyze ATP and use its chemical energy to facilitate the Fe-S cluster transfer process, and the substrate binding domain (SBD), which directly interacts with the substrate, IscU, the scaffold protein of an Fe-S cluster. In the present work, we prepared the isolated SBD construct of HscA (HscA(SBD)) and conducted the solution-state nuclear magnetic resonance (NMR) experiments to have its backbone chemical shift assignment information. Due to low spectral quality of HscA(SBD), we obtained all the NMR data from the sample containing the peptide LPPVKIHC, the HscA-interaction motif of IscU, from which the chemical shift assignment could be done successfully. We expect that this information provides an important basis to execute detailed structural characterization of HscA and appreciate its interaction with IscU.

• Journal of Korean Academy of Nursing
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• v.40 no.6
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• pp.852-862
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• 2010

Purpose: This study was done to investigate differences in health behaviors by job stress level in male and female workers in a large-sized company. Methods: Participants were 576 male and 228 female workers who completed questionnaires. Job stress was measured using the 'Short Form Korean Occupational Stress Scale (SF-KOSS)'. Health behaviors included smoking, alcohol consumption, regular exercise, and diet. Frequency, mean, SD, chi-square test, and multivariate logistic regression using SAS version 9.1 were used to analyze data. Results: Smoking, drinking and regular exercise rates were not different by job stress level in male or female workers. Only regular diet was significantly different by job stress level in male and female workers. From multivariate analysis, the alcohol consumption rates for female workers differed by marital status. Regular exercise rate was significantly related to age for male workers and type of employment for female workers. After adjusting for demographic and work-related characteristics, regular diet significantly differed by shift work for male workers and marital status and shift work for female workers. Conclusion: The findings of the study indicate that nursing interventions should be developed to manage job stress to improve diet habits for male and female workers in large-sized companies.

• Safety and Health at Work
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• v.4 no.4
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• pp.197-200
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• 2013

Background: A variety of sociodemographic factors, such as gender, age, household income, and educational level, influence individuals' likelihood of smoking.Work-related factors may also be linked to smoking behavior.We sought to investigate the relationship between smoking and work environment in South Korea. Methods: We analyzed data from the Fifth Korean National Health and Nutrition Examination Survey to determine whether there was an association between smoking and occupation type (e.g., manual, nonmanual, or service work), night-shift work, and hours worked/week (e.g., <40, 40-48, 49-60, or >60 hours) for 4,685 workers. Regression models were adjusted for sociodemographic variables such as age, recent alcohol consumption, hours slept, educational level, and household income. Results: The prevalence of smoking was 50.1% in men and 7.2% in women. For women, manual workers had 2.34 times [95% confidence interval (CI): 1.02-5.36] greater odds of smoking compared with nonmanual workers, whereas service workers had 2.37 times greater odds (95% CI: 1.28-4.40). Furthermore, women who worked 49-60 hours had 2.21 times greater odds of smoking (95% CI: 1.10-3.75) as compared with women who worked 40-48 hours. Conclusion: Women who work long hours or who are employed in service or manual positions are more likely to smoke. These results indicate a need in South Korea to target these specific groups when creating nonsmoking policies.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1764-1770
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• 2020

The present work was mainly concerned with studying the operation of RC-phase shift oscillator based on MOSFET type 2N6660 under the influence of different temperature levels ranging from room temperature (25 ℃) up-to135 ℃ and gamma-irradiation up-to 3.5 kGy. In this concern, both the static (I-V) characteristic curves of MOSFET devices and the output signal of the proposed oscillator were recorded under ascending levels of both temperature and gamma-irradiation. From which, it is clearly shown that the drain current was decreased from 0.22 A, measured at 25 ℃, down to 0.163 A, at 135 ℃. On the other hand, its value was increased up-to 0.49 A, whenever the device was exposed to gamma-rays dose of 3.5 kGy. Considering RC-phase shift oscillator, the oscillation frequency and output pk-pk voltage were decreased whenever MOSFET device exposed to gamma radiation by ratio 54.9 and 91%, respectively. While, whenever MOSFET device exposed to temperature the previously mentioned parameters were shown to be decreased by ratio 2.07 and 46.2%.

• Sleep Medicine and Psychophysiology
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• v.24 no.1
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• pp.12-18
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• 2017

Adequate amount and quality of sleep are important for metabolic control in patients with type 2 diabetes. Too short or too long sleep time disrupts glycemic control in both prediabetes and type 2 diabetic patients. Circadian misalignment such as shift work is also associated with an increased risk of developing type 2 diabetes. Clinicians should pay attention to the sleep problems and circadian patterns of patients. However, the pathophysiologic mechanism of the association between sleep and diabetes is likely to be complex and bidirectional. The underlying mechanism remains poorly understood, and further research is warranted.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.157-165
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• 2007

The Work-Related Musculoskeletal Disorders (WMSDs) can be occurred by various factors such as repetition, forceful exertions and awkward postures. Especially, occurrences of the WMSDs on the waist and lower limb are reported in workplaces, demanded standing postures for a long time, in service and manufacturing industry. The static and standing postures without movement for a long time increase work loads to the lower limb and the waist. Accordingly, anti-fatigue mat or anti-fatigue insole is used as a preventing device of the WMSDs. However anti-fatigue mats are limited in space and movement. In this study, multi-elastic insoles are designed and shown the effects of the workload reduction for a long time under the standing work. The foot pressures and EMG (Electromyography) are measured at 0 hour and after 2 hours by 6 health students in their twenties. The 6 prototype insoles are designed with three elastic (Low, Medium and High). These insoles are compared with no insole (insole type 7) as control group. The EMG measurement was conducted to waist (erector spinae muscle), thigh (vastus lateralis muscle) and calf (gastrocnemius muscle). The foot pressure is analyzed by mean pressure value and the EMG analysis is investigated through MF (Median Frequency), MPF (Mean Power Frequency) and ZCR (Zero Crossing Rate). The results of the foot pressure show that the multi-elastic insoles had smaller foot pressure value than that of no-insole. Moreover, Insole 2 and Insole 3 have the smallest increasing rate in foot pressure. The EMG results show that the multi-elastic insoles had smaller EMG shift value than that of no-insole in 2 hour, and then shift value shows the smallest value in Insole 2. Therefore, this study presents that the multi-elastic insoles have reducing effects of the work load for a long time standing work in both side of foot pressure and EMG.