• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_2
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• pp.285-291
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• 2023

In this paper, in order to secure the safety and productivity of pine cone harvest, modeling and structural analysis of the hammering system for pine cone harvest drone that can easily access pine cone of Pinus koraiensis and collide with them to harvest them was performed. It calculate the equivalent stress for the structure of the hammering system and the yield strength of the applied material by applying the shear force of the stalk at which the pine cone is separated from the branch, and it is to verify the safety of the structure and propose an optimal design through appropriate factor of safety and design change. The shear force of the stalk at which the pine cone was separated from the branch was 468 N, and was applied to both ends of the hammering system. The yield strength of SS400 steel used in the hammering system is 245 ㎫, and the design change and structural analysis were performed so that the Von Mises stress could be less than 122.5 ㎫ by applying the factor of safety of 2.0 or more. As a result of the structural analysis of the frist modeling, the Von Mises stress was 220.3 ㎫, the factor of safety was 1.12, and the stress was concentrated in the screw fastening holes. As a result of the design change of the screw fastening holes, the Von Mises stress was 169.4 ㎫, the factor of safety was 1.45, and the stress was concentrated on the side part. As a result of the design change by changing screw fastening holes and adding ribs, the Von Mises stress was 121.6 ㎫, and the factor of safety was 2.02. The safety of the hammering system was secured with an optimal design with little change in mass. There was no deformation or damage as a result of experimenting on pine cone harvest by manufacturing the hammering system with an optimal design.

• Safety and Health at Work
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• v.1 no.1
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• pp.87-97
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• 2010

Objectives: This study was conducted to investigate the effect of trust on work stress. Trust can be classified into three dimensions; social trust, institutional trust, and trust in others. The relationship between work stress and trust is regarded as having three components. First, trust has an influence on work stressors as an antecedent variable; secondly, trust modifies the effect of the various stressors, and finally, trust is one of the stressors. Methods: Data for this study was collected by interviews and self-administered structured questionnaires from 376 Korean and 77 Japanese workers in small businesses. Subjects were selected by two stage stratified random sampling from the working population of manufacturing industries. Results: Three different positions of trust are significantly related with the stress causation web. Social trust, institutional trust and trust in others significantly influence different work stressors in both Korean and Japanese workers. Three different kinds of trust influence work stressors among Korean workers, but institutional trust has no impact on work stressors among Japanese workers. As a moderating variable for perceived stress, distrust in an employer is statistically significant in both groups. However, stress symptom prevalence among Korean workers is modified by caution, trust in career development, and distrust in co-workers, but that of Japanese workers is modified only by distrust in employer. Job satisfaction of Korean workers is affected by general trust, utility of relation, institutional trust and trust in employer, but among Japanese workers, caution, reputation and trust in employer have influence on job satisfaction. Conclusion: The effect of trust on work stress, perceived stress, stress reaction and job satisfaction are different among Korean workers and Japanese workers. Three dimensions of trust have three different positions as antecedent, moderating and mediating factors in stress causation.

• 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.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.401-406
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• 2011

This study presents the stress safety analysis of a cylinder, which is manufactured by a tempered ASTM D2, tempered SM45C and normalized SM45C materials, respectively. The inner diameter of three cylinder models are 85mm, 95mm, and 11 Omm and the total length of a cylinder is 2,365mm for a high pressure injection molding machine. The FEM computed results show that the inner diameter of 85mm with a thick thickness of 62.5mm may produce the injection pressure of 325MPa and the inner diameter of 110mm with 50mm thickness reduces up to the injection pressure of 220MPa because of a reduced thickness of a cylinder. These injection pressures are enough for a high pressure injection molding machine assembled by ASTM D2 cylinder. And also, an injection cylinder manufactured by a tempered SM45C material in which is low priee may produce 225MPa injection molding pressure and this may sufficiently endure stress safety compared to that of ASTM D2 cylinder material. Thus, this study recommends that tempered SM45C cylinder is appropriated for a mild injection molding machine as an alternative cylinder material when the safety strength and low prices are considered. But the normalized SM45C cylinder material does not meet a stress safety of yield strength in general.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.4
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• pp.293-300
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• 2018

Purpose: This study was done to identify the relationship between nurses' compliance with safety guidelines for the use of antineoplastic agents, observable symptoms, and stress from occupational exposure. Methods: The participants were 172 nurses from six general hospitals in a metropolitan area. They had administered antineoplastic agents at least three months prior to the study. Data were collected using self-report questionnaires, and then analyzed using SPSS/WIN 23.0 for descriptive statistics, t-test, one-way ANOVA, $Scheff\acute{e}$ method, and Pearson correlation coefficient. Results: The average score on the guideline for safety compliance was 87.75 points out of a total of 100. The average score for observable symptoms of exposure to antineoplastic agents was 30.12 (28~56) points, and that for mean stress was 33.52 (15~60) points. Observable symptoms and stress from occupational exposure showed a statistically significant positive correlation (r=0.34, p<.001). Conclusion: To increase the degree of compliance with safety guidelines for antineoplastic agents, hospitals should lower the chance of exposure to antineoplastic agents, as well as minimize the observable symptoms and stress from occupational exposure. Periodic education and policy support are needed to improve compliance with safety guidelines for antineoplastic agent use.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.86-92
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• 2009

In the safety check of gravity dams at earthquake, there have been two types of analysis conducted simultaneously; one is stability analysis and the other stress analysis. But those are essentially the same calculation other than the former considers the dams rigid, while the latter considers the dams' dynamic characteristics which results in the amplification of response acceleration on the upper part of dam body. In this paper, the identity of those two methods is verified by example calculation in terms of stability check of gravity dam. It can be concluded that if stress analysis were performed, stability check of gravity dam could be accomplished with the results from stress analysis, removing unnecessary present dual calculation practice.

• The Korean Journal of Emergency Medical Services
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• v.20 no.2
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• pp.37-49
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• 2016

Purpose: This study investigated the current status of post-traumatic stress and related factors among safety managers in Korea National Parks. Methods: The study subjects were 109 safety managers working in Korea National Parks. General characteristics, job-related characteristics, experience of traumatic events and post-traumatic stress were collected by self-reported questionnaires through the mail. The associated factors with post-traumatic stress was analyzed by t-test, ANOVA and multiple linear regression. Results: Overall score of post-traumatic stress was $10.32{\pm}11.37$ and 12.8% was the high-risk group of post-traumatic stress disorder. In simple analysis, score of post-traumatic stress was associated with drinking frequency, disease history, duration of career, delay of rescue, provided the break, rest space and the number of experiences of traumatic events. Finally, the score of post-traumatic stress was significantly higher in subjects who experienced 3 (B=9.141, SE=3.538) or more than 4 (B=11.367, SE=3.063) traumatic events compared to subjects without experience of traumatic event. Conclusion: The score of post-traumatic stress was $10.32{\pm}11.37$ and 12.8% was the high-risk group among safety managers in Korea National Parks. Post-traumatic stress was associated with the experience of traumatic events. Management of safety managers after mobilization or experience of traumatic events will be helpful to decrease of post-traumatic stress.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.79-88
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• 2017

The purpose of this study is to analyze the effects of personal, job, and health care characteristics of firefighters on musculoskeletal disorders (MSDs) and job stress. This survey was participated 591 firefighters in jeonnam and Busan city. The survey consisted of 1) personal, job, and health care characteristics measurement, 2) job stress measurement (KOSS, Korean Occupational Stress Scale), 3) musculoskeletal disorders symptoms mesurement. The analysis of the data was using SAS 9.1 Ver. The statistics analysis was performed the frequency, percentage, average, and standard deviation for each survey item. The Chi square analysis was performed to analyzed the effects of personal, job, and health care characteristics on MSDs and job stress. According to the results of the study on musculoskeletal disorders symptoms, 49.6% of the subjects perceived pain related to musculoskeletal diseases. The total score for job stress was 51.6 (SD 12.9), which was the highest 50% when compared to the Korean job stress standard (male). Age, department, work experience, working type, position, and sleeping time were found to affect musculoskeletal disorders and job stress.

• Journal of the Korean Society of Safety
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• v.26 no.6
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• pp.79-84
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• 2011

There have been so many studies related to job stress or musculoskeletal disorders(MSDs) in the shipbuilding industry. However, study of employee performance evaluation that reflect on the industrial features of the deckhouse manufacturing industry has not been established. Therefore, this study aimed to evaluate workers' job stress and work ability through statistical significance tests according to age, work types, years of service, work forms and sex. For this, the study conducted a job stress test using the Korean Occupational Stress Questionnaire Short Form, and employee performance evaluations using the Work Ability Index(WAI) of the Finnish Institute of Occupational Health (FIOH) on 536 workers in the deckhouse manufacturing industry. MINITAB statistics program was used for statistics analysis and significance was verified with the Kruskal-Wallis test, a corporate body of nonparametric statistical analysis. As a result, employee performance had significant differences, depending on age, work types, years of service and sex, and job stress also depended on the number of service year and work form. Additionally, it was found that employee performance decreased more as job stress increased.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1233-1235
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• 2008

The purpose of this study is to analyze human factors - stress, alcohol, fatigue - of the railway driver in domestic railway industry. This study proposes railway safety improvement of domestic railway by intensively comparing railway safety system overseas to reinforce domestic railway safety. Domestic railways well known the well-organized railway safety culture has brought up safety issues on their process of private management. With this process, also, domestic safety is requested by increasing sense of the safety for general public. This study expects Korean railways to become a well-organized that as removing insecure factors of domestic railway based on result comparing and analyzing the manual, factors and requirements of guideline for internal and external safety culture.