• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.641-642
• /
• 2006

The purpose of this work is to investigate the effect of work load on heart rate variability (HRV) which is widely used marker of the autonomic nervous system activity. Average heart rate, rating of perceived exertion, and the power spectrum of heart rate variability were investigated in seven healthy males during exercise at various work loads. The subjects were divided into two groups according to the average heart rate during exercise, group 1 with lower heart rate and group 2 with higher heart rate. HF component showed decrease followed by increase with workload. Accordingly, the LF/HF ratio showed increase followed by decrease with workload. The peak in LF/HF ratio of group 1 was at the lower workload than that of group 2.

• International Journal of Advanced Culture Technology
• /
• v.11 no.2
• /
• pp.298-309
• /
• 2023

The mouse as an input device has undoubtedly brought convenience to users due to its intuitiveness and simplicity, but it also brought unprecedented issues such as carpal tunnel syndrome (CTS). As a result, the necessity of alternative input devices that put less strain on the wrist, while still providing the convenience of a conventional mouse, has emerged. Unfortunately, there have been several research about alternative devices to replace a mouse, however, they showed inconsistent results. This study suggests that those inconsistent results may stem from the type and the difficulty of tasks used in previous studies. Therefore, we designed this study to compare the performance and perceived workload of three input devices (Mouse/Trackball/Touchpad) in each condition in terms of task type (Targeting/Tracking) and difficulty level (Easy/Hard). The results indicated that there were significant performance differences and no significant workload differences among the three devices, and the interactions were observed in some conditions. These results can provide users with practical guidelines to choose the optimal input device according to their needs or purpose.

• Physical Therapy Korea
• /
• v.16 no.1
• /
• pp.42-51
• /
• 2009

The purpose of this study was to develop a checklist of risk factors for quantitative assessment of musculoskeletal complaints in shipbuilding workers. A key point was to develop comprehensive a checklist including the worker's physical ability, as ergonomic and workload factors. ln the first, through correlation analysis between musculoskeletal complaints and physical abilities in shipbuilding workers, risk factors related to physical abilities were selected. In the second, after the development of a checklist was composed of physical, ergonomic and workload factors, factor analysis was used to test the validity of the developed checklist. Each factors selected finally showed that physical factors were hand grip strength, spinal curvature, and flexibility (sit to reach), ergonomic factors were posture, total exposed time, duration, and force of working, and workload factors were physical and psychological workload perceived by worker. The results showed that musculoskeletal complaints was associated with physical abilities (p<.05). The developed checklist had a reliability of .761 (Cronbach=.761) and a validity and explanation of 54.9%. The criterion of management was classified in 4 stages by relative weights of each factor. It is suggested that active intervention is needed to reduce musculoskeletal complaints in workers with more than a 14.31 score.

• Journal of the Ergonomics Society of Korea
• /
• v.23 no.4
• /
• pp.45-56
• /
• 2004

The purpose of this study is to evaluate perceived discomfort of working postures in terms of upper body (back, shoulder, and elbow) flexions when an external load varies. Eighteen subjects participated in an experiment of appraising perceived discomfort of varying upper body postures with three levels of external loads given. The ANOVA results showed that the perceived discomfort of upper body postures was significantly affected by the external load. It was also apparent that the interactions between external load and upper body posture were significant (p< 0.001). The result implies that a new posture classification scheme for workload assessment methods may be in need to reflect such interactions between external load and upper body posture. In order to support the statement, a regression model of perceived discomfort of upper body postures obtained from the experiment was developed and compared to that of perceived discomfort of seven work-related postures found in automobile assembly operations. The correlation coefficient between predicted and actual values of perceived discomfort was about 0.96. It is expected that the result help to properly estimate the body stress resluting from worker's postures and external loads and can be used as a valuable design guideline on preventing work-related musculoskeletal diseases in industry.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.1242-1242
• /
• 2022

Annually, several construction workers fall ill, are injured, or die due to heat-related exposure. The prevalence of work-related heat illness may rise and become an issue for workers operating in temperate climates, given the increase in frequency and intensity of heatwaves in the US. An increase in temperature negatively impacts physical exertion levels and mental state, thereby increasing the potential of accidents on the job site. To reduce the impact of heat stress on workers, it is critical to develop and implement measures for monitoring physical exertion levels and mental state in hot conditions. For this, limited studies have evaluated the utility of wearable biosensors in measuring physical exertion and mental workload in hot conditions. In addition, most studies focus solely on male participants, with little to no reference to female workers who may be exposed to greater heat stress risk. Therefore, this study aims to develop a process for objective and continuous assessment of worker physical exertion and mental workload using wearable biosensors. Physiological data were collected from eight (four male and four female) participants performing a simulated drilling task at 92oF and about 50% humidity level. After removing signal artifacts from the data using multiple filtering processes, the data was compared to a perceived muscle exertion scale and mental workload scale. Results indicate that biosensors' features can effectively detect the change in worker physical and mental state in hot conditions. Therefore, wearable biosensors provide a feasible and effective opportunity to continuously assess worker physical exertion and mental workload.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.24 no.1
• /
• pp.89-99
• /
• 2018

Purpose: The purpose of this study was to identify the influence of professional self-concept, job overload, and perceived organizational support on job involvement in clinical nurses. Methods: The participants in this study were 232 nurses who were working in five general hospitals in city D. Data was collected using self-reported questionnaires from August 16 to September 15, 2016. The data was analyzed using the IBM SPSS 19.0 program. Results: Job involvement of clinical nurses was influenced by professional self-concept, perceived organizational support, turnover intention, age, and monthly income. These variables explained 47.6% of job involvement of clinical nurses, and professional self-concept was the most significant factor in job involvement. Conclusion: The findings indicate that the job involvement of clinical nurses is influenced by professional self-concept and perceived organizational support. Consequently, it is necessary to increase professional self-concept and perceived organizational support for nurses' job involvement.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.28 no.4
• /
• pp.374-381
• /
• 2018

Objective: This study was carried out to examine the factors affecting the fatigue and health promotion behavior of hairdressers and their respective levels. The data were collected from 195 hairdressers working in beauty shops in Daegu and Gyeongsangbuk-do Province using self-administered questionnaires over the period from July 1 to July 31. Methods: A multiple regression model was used to study the factors influencing fatigue and health promotion behavior among hairdressers. Results: This study showed a statistically significant difference in perceived fatigue levels and health promotion behavior according to age, family type, education level, work period, work position, and fatigue level in the past one week. In addition, multiple regression showed that statistically significant factors affecting perceived fatigue were education level, work period, and fatigue level in the past one week. Statistically significant factors affecting health promotion behavior were age and fatigue level in the past one week. The level of perceived fatigue among hairdressers tended to be higher than other workers, and their level of practice of health promotion behavior was generally lower. Conclusions: The improvement of the work environment, such as through the distribution of a proper workload considering workers' characteristics and strengthening of exercise programs to reduce the fatigue level and promote health practices among hairdressers is needed.

• Journal of the Ergonomics Society of Korea
• /
• v.31 no.2
• /
• pp.281-289
• /
• 2012

Objective: The purpose of this study is to evaluate the potential risk of shoulder muscle at particular working postures in sitting. Background: The cause of shoulder pain needs to be specifically studied in relation with particular shoulder postures to prevent shoulder MSDs in workplace. Method: In this study MVC, fatigue and subjective workload were investigated depending on the change of shoulder posture. An experiment was designed to evaluate the six shoulder muscles at nine shoulder postures including the combination of 30(adduction), 0, 30(abduction) degrees and 60, 90, and 120 degrees of shoulder flexion. Surface electrodes were attached to the middle trapezius, inferior middle trapezius, anterior deltoid, posterior deltoid, serratus anterior and teres major. Thirteen subjects participated in the experiment. Dependent variables were RPE (rating of perceived exertion), MVC(maximum voluntary contraction) and MPF(mean power frequency) shift by EMG (electromyography). Results: The middle trapezius and inferior middle trapezius were not significantly fatigued at all postures. The decline of MPF slope was less than 10% at all postures. The anterior deltoid was significantly fatigued all postures. The decline of MPF slope was more than 10% at all postures. The posterior deltoid was significantly fatigued 30 degrees of adduction and 90 degrees of flexion. And, neutral and 30 degrees of abduction postures were fatigued more than 90 degrees of flexion. The serratus anterior was significantly fatigued except for 30 degrees of adduction and 60 degrees of flexion posture. The teres major was significantly fatigued except for neutral and 60 degrees of flexion, 30 degrees of abduction and 60 degrees of flexion posture. Conclusion: It was found that a certain muscle was fatigued fast at particular posture compared to other muscles, which would mean that a certain shoulder muscle at particular posture could be easily exposed to the risk of musculoskeletal disorders than other muscles. Application: It is expected that the result can be applied to design workplace using shoulder muscles.

• Journal of the Korean Society of Safety
• /
• v.32 no.3
• /
• pp.90-98
• /
• 2017

The purpose of this study was to examine the effect of employment type(direct employment, dispatch and service supplier) on risk factor exposure, health and satisfaction. The data of the 4th wave of Korean Working Conditions Survey (KWCS) conducted by Korea Occupational Safety and Health Agency (KOSHA) in South Korea was used. Business support service industry and manufacturing industry were selected as appropriate industries for analysis. In the final analysis, 5,865 in the manufacturing industry and 1,361 in the service support industry were included. Various variables related risk, safety, satisfaction and health such as risk factor exposure, MSDs exposure, work environment satisfaction, injury probability, dangerous work, workload, physical health problem, perceived health, positive emotions, stress, participation for decision making and experience of accident/disease were analyzed and company size and age was controled. An ANCOVA was conducted to identify significant mean differences of risk, safety, satisfaction and health related variables among direct employed workers, dispatch and service supplier workers. The results showed that all the variables except stress showed a significant difference depending on employment type in the service supply industry. In the manufacturing industry, there were significant difference in the risk factor exposure, MSDs exposure, work environment satisfaction, workload, physical health problem, perceived health, and participation depending on employment type. These results indicated that the risks are unloaded to subcontract and outsourcing company workers. Based on these results, the implications of this study and suggestions for future research were discussed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.6
• /
• pp.3911-3918
• /
• 2015

This study was conducted to identify the effect of nurses' empathy on their job stress. The subjects of this study were 192 nurses working at 5 general hospitals. The empathy and job stress were surveyed by using structured questionnaire from June 1 to August 31, 2014. The nurses' overall job stress was 3.86 out of 5 and among the domains of job stress, stress of relationship with patients and their carer was 4.22, stress of relationship with medical doctors was 4.21, and stress related to nursing tasks was 4.01. Factors influencing job stress were gender, pay satisfaction, perceived amount of workload, and fantasy from empathy. These findings suggest that in order to improve clinical nurses' job stress, there should be organizational efforts to regulate the pay level and workload and to develop programs for lowering perceived job stress among nurses by managing fantasy from empathy.