• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.272-282
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• 2004

Stress is a primary health promotion issue in worksite research because psychological distress is closely related not only to workers　 health status but also to their job performance. This study identified the work environment and work condition factors affecting workers　 stress symptoms among the Korean manufacturing factory workers. A total of 7,818 factory workers employed in 1,562 manufacturing companies participated in the Korean nation-wide occupational health survey conducted by the Korean Occupational Safety and Health Agency in 2003. Participants were selected by the stratified proportional sampling process by standardized industry classification, company size, and locations. Trained interviewers visited the target companies and interviewed the factory workers randomly selected in each company. Work environments included physical work environments (temperature, noise, hazardous organic compounds, and so on) and psychological work environments (job demands, job control, and social support at work), and work conditions included daily working hour, rest time, and so on. Men were 71.5% and the mean age was 34.0 years old. The average working period in the present company was 6.9 years. The average stress score was 26.2 under the perfect score, 50, which means the moderate level of stress. Perceived stress had significant correlations with young age, poor physical work environment, high fatigue, bad perceived health status, and high job demands in Pearson's simple correlation analysis. Perceived health status and perceived fatigue explained 21% variance of stress symptoms and the work environment factor explained 4.8% of that; however, work condition did not have the sufficient effect. In particular, psychosocial work environment variables (job demand, job control, and social support at work) had a clear effect on stress symptoms rather than the physical work environments. Poor perceived health status, severe perceived fatigue, poor physical work environment, high job demands, low social support, heavy alcohol consumption and little exercise were significantly related to high stress symptoms in the Korean manufacturing workers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5A
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• pp.873-880
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• 2006

PSC composite bridge with precast decks which was designed by the proposed horizontal shear equation was fabricated. Fatigue test was performed to evaluate the endurance of shear connection and the behavior of PSC composite bridge. After all the fatigue loading were applied, no crack and no residual slip were occurred. The flexural stiffness of PSC composite bridge was maintained the initial value, and demage of shear connection was not occurred. To verify the applicability of horizontal shear equation and shear connection detail and to evaluate the strength of PSC composite bridges, static test was also executed. PSC composite bridges with precast decks had 2.08 safety factor which was the ratio of crack to serviceability load and showed ductile behavior after ultimate load. Test results showed that the proposed design equation of the shear connection gave reasonable horizontal shear connection design. Fast and easy construction would be achieved using the suggested precast system.

• Journal of Korean Academy of Nursing
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• v.50 no.5
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• pp.658-670
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• 2020

Purpose: This study aimed to identify the predictors of blood and body fluid exposure (BBFE) in multifaceted individual (sleep disturbance and fatigue), occupational (occupational stress), and organizational (hospital safety climate) factors, as well as infection prevention behavior. We also aimed to test the mediating effect of infection prevention behavior in relation to multifaceted factors and the frequency of BBFE. Methods: This study was based on a secondary data analysis, using data of 246 nurses from the Shift Work Nurses' Health and Turnover study. Based on the characteristics of zero-inflated and over-dispersed count data of frequencies of BBFE, the data were analyzed to calculate zero-inflated negative binomial regression within a generalized linear model and to test the mediating effect using SPSS 25.0, Stata 14.1, and PROCESS macro. Results: We found that the frequency of BBFE increased in subjects with disturbed sleep (IRR = 1.87, p = .049), and the probability of non-BBFE increased in subjects showing higher infection prevention behavior (IRR = 15.05, p = .006) and a hospital safety climate (IRR = 28.46, p = .018). We also found that infection prevention behavior had mediating effects on the occupational stress-BBFE and hospital safety climate-BBFE relationships. Conclusion: Sleep disturbance is an important risk factor related to frequency of BBFE, whereas preventive factors are infection prevention behavior and hospital safety climate. We suggest individual and systemic efforts to improve sleep, occupational stress, and hospital safety climate to prevent BBFE occurrence.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.488-493
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• 2005

In gun stabilization systems, the torque comes from the unbalance mass of gun and the base acceleration is an important source of disturbance which degrades stabilization performance. Fatigue of gear train is another important factor affecting structural safety problems. In this paper, a feedback control gain is designed by optimal control weighting to difference between motor and gun velocity, and a feedforward controller using FXLMS algorithm is adopted to investigate those problems. Experimental results show that the feedforward compensator based on FXLMS can reduce the disturbance effects. The directional convergence property according to initial conditions of the FXLMS is also shown through experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2344-2352
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• 2000

Mechanical joints such as bolted or riveted joints are widely used in mechanical components. The reliable determination of the stress intensity factors for cracks in bolted joints is needed to evaluate the safety and fatigue life of them. The weight function method is an efficient technique to calculate the stress intensity factors for various loading conditions because only the stress analysis of an uncracked model is required. In this paper the mixed-mode stress intensity factors for cracks in bolted joints are obtained by weight function method, in which the coefficients of weight function are determined by finite element analyses for reference loadings. Critical inclined angle that mode I stress intensity factor becomes maximum is determined and the effects of crack length and the magnitude of clearance on critical inclined angle are investigated.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.212-217
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• 2000

The reliable determination of the stress intensity factors for cracks in bolted Joints is needed to evaluate the safety and fatigue life of them widely used in mechanical components. The weight function method is an efficient technique to calculate the stress intensity factors for various loading conditions using the stresses of an uncracked model. In this paper the mixed-mode stress intensity factors for cracks in bolted joints are obtained by weight function method, in which the coefficients of weight function are determined by finite element analyses far reference loadings. The effects of the magnitude of clearance and factional coefficient on the stress intensity factors are investigated.

• Journal of Industrial Convergence
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• v.1 no.2
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• pp.17-31
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• 2003

Many risk factors with the onset of Low Back Pain(LBP) have been identified, however, lifting out of Manual Material Handling(MMH) was the most important factor to the LBP. Injuries due to lifting took account for 34.0%(227,291) out of the total overexertion in MMH(668,084). The weight, vertical location, twist angle, lifting frequency, and lifting posture were reviewed in this study. Technical information for using the revised lifting equation to evaluate a variety of two - handled manual material handling tasks was suggested. To measure worker's fatigue in lifting task, Lifting Index Simulator(LIS) was create under the revised NIOSH(National Institute for Occupational Safety and Health) lifting equation. For the implementation of the LIS, data was collected in A company manufactures various paints in Si-Wha industrial complex, Kyunggi-Do. The results of the Lifting Index(LI) were analyzed by MANOVA to find the relation with lifting variables collected. It was found that horizontal distance, vertical distance, travelling distance and frequency were significant at the 0.01 level and weight was significant at the 0.05 level. The purpose of this paper is to reduce the chronical low back pain for the manual material handlers.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.153-160
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• 2013

The purpose of this study was to compare biomechanical factors on badminton shoes between anti-slip outsole and non anti-slip outsole. Six subjects participated in this experiment. For three-dimensional analysis, eight cameras (Oqus 3series, Qualisys) were used to acquire raw data, and then the parameters were calculated and analyzed with Visual-3D. In conclusion, the patterns of spent time during side step, and maximum velocities of CoGs were consistent without joint angles of lower extremities in spite of small differences. Those of GRFs, and moment of lower extremities were absolutely consistent. This trend of biomechanical factors was that Y shoe (ante-treatment) was much greater and PS shoe (treatment) was greater than Y shoe (treatment). (That was, Y shoe (ante-treatment) > PS shoe (treatment) >Y shoe (treatment)). The findings of this study showed that anti-slip outsole was effective and brought increasing performance and decreasing injuries. It is suggested that further study of these phenomena will help understand many aspects of human locomotion, including work, performance, fatigue and possible injuries.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.48-53
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• 2011

In this study, it is to verify the applicability for a simplified model(IEC61400-2, Design Require-ments for Small Wind Turbines, 2006-03) is the international standard is used to the structural design. In the design process of a wind turbine, the safety of a designed wind turbine is one of the most important factors. The simplified model can be used to determine the design load for small wind turbines. So, this paper has been re-evaluated a small wind turbine design loads that produced already. As a result, the material characteristic value(Rchar) of Blade, Rotor shaft and the tower are $90E6[N/m^2]$, $441E6[N/m^2]$ and $94E6[N/m^2]$. Therefore, the value of the applied safety factor to each part of the survival probability of 95% are satisfied.

• Journal of the Korean Society of Safety
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• v.38 no.4
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• pp.32-38
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• 2023

Job stress factors are factors that induce biological, psychological, and behavioral responses in individuals when they encounter mental and physical stimuli in the workplace. According to occupational safety and health standards, employers are responsible for the health consequences of job stress when workers engage in activities that result in high levels of physical fatigue and mental stress. Such activities include long working hours, shift work (including night shifts), driving vehicles, and operating precision machinery. Therefore, precautionary measures should be implemented. Following the COVID-19 epidemic, the logistics industry in Korea has experienced rapid growth owing to the shift from offline to online platforms facilitated by advanced digital infrastructure. Consequently, this study conducted a survey to analyze job stress factors among delivery workers. The survey utilized a Korean job stress factor assessment tool comprising 43 items and analyzed job stress factors considering the work characteristics of the courier business field obtained from responses provided by 421 courier workers nationwide. The survey analysis revealed that the physical environment, job demands, and job autonomy exhibited higher stress indices among Korean workers. Furthermore, the younger the age, the higher the stress on job demands, whereas the higher the age, the higher the stress on relationship conflict, job instability, and workplace culture. In addition, daytime delivery work was associated with higher stress levels in job demands and job instability compared with nighttime delivery work. These findings can serve as foundational data for reducing and preventing job stress among courier workers, whose workload has increased owing to the growth of the logistics industry.