• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.79-89
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• 1999

A quantitative fit test, condensation nuclei counting (Portacount 8025, TSI), was performed concurrently with a banana oil (isoamyl acetate: IAA) qualitative fit test (MSA) to evaluate reliability on IAA QLFT and correlation between two methods. One brands of quarter mask (3M model 7500 medium) was prepared for QLFT with HEPA filter and gas & vapor removing media, i.e., combination cartridge. 110 subjects (65 male, 45 female) were fit tested QNFT and QLFT each three times. For a wearer combination having a FF<10, as determined by CNC QNFT, the point es timate (${\beta}$-error) of the probability of that combination not being rejected by the banana oil QLFT was found to be 0.0 with 95% confidence that this statistic is not expected to exceed 0.15. For a wearer combination having a FF<100, as determined by CNC QNFT, the point estimate of the probability of that combination not being rejected by the banana oil QLFT was found to be 0.07 with 95% confidence that this statistic is not expected to exceed 0.13. The uncertainty associated with each estimate, however, is large due to the small number of study subjects with inadequately fitting respirators.

• Journal of Preventive Medicine and Public Health
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• v.47 no.5
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• pp.253-257
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• 2014

Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a recent World Health Organization report, arsenic from contaminated water can be quickly and easily absorbed and depending on its metabolic form, may adversely affect human health. Recently, the US Food and Drug Administration regulations for metals found in cosmetics to protect consumers against contaminations deemed deleterious to health; some cosmetics were found to contain a variety of chemicals including heavy metals, which are sometimes used as preservatives. Moreover, developing countries tend to have a growing number of industrial factories that unfortunately, harm the environment, especially in cities where industrial and vehicle emissions, as well as household activities, cause serious air pollution. Air is also an important source of arsenic exposure in areas with industrial activity. The presence of arsenic in airborne particulate matter is considered a risk for certain diseases. Taken together, various potential pathways of arsenic exposure seem to affect humans adversely, and future efforts to reduce arsenic exposure caused by environmental factors should be made.

• Journal of Welding and Joining
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• v.29 no.2
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• pp.64-71
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• 2011

In this paper, crack propagation analyses in the inner diameter (ID) repair weld of the dissimilar metal weldment of a nozzle were performed using a finite element alternating method (FEAM). To calculate the theoretical solution for the crack tip stress intensity factor, a weak type singular integral equation consisted of crack surface traction and dislocation density function was constructed and solved in conjunction with the FEAM. A two-dimensional axisymmetric finite element nozzle model was prepared and ID repair welding was simulated. An initial crack, 10% depth of weld thickness, was assumed and crack propagation trajectory from the initial crack to the 75% depth of thickness was calculated using the FEAM. Crack growth versus time curve was also calculated and compared with the curves obtained from ASME code method. With the method constructed in this paper, crack propagation trajectory and crack growth time were calculated automatically and effectively.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.549-555
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• 2013

Objective: The purpose of this study was to compare the performance of drilling on the ceiling in three different postures (standing, standing on the ladder and supine on the height adjusted board) and the subjective responses of perceived discomfort after the drilling. Background: Overhead work has been identified as a major occupational risk factor and has been a main research subject. Method: Ten young participants drilled 20 holes at the pre-marked places on the ceiling in three different postures. The drilling duration, resting and drilling heart rate were measured. The levels of perceived discomfort at neck, shoulder, elbow, hand and overall body were asked at the end of each task. Results: The working posture affected the heart rate after the drilling. Perceived discomfort in the neck decreased significantly in supine compared to drilling on the ladder. Conclusion: The results of this study suggest that drilling in supine can be an alternative way to reduce the drilling heart rate and the level of perceived discomfort in the neck without sacrificing the productivity. Application: The results of this study would be considered when drilling on the ceiling is required in construction workers.

• Journal of Acupuncture Research
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• v.18 no.6
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• pp.70-83
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• 2001

Objective : In order to investigate symptoms prevalence related to visual display terminal(VDT) syndrome, and to evaluate the variables affecting the development of the VDT syndrome. Methods : a questionnaire survey was conducted on 127(81 men and 46 women) VDT operators who had been studied in Soongsil University graduated school in Seoul. Result : As a result of analysis with data collected by questionnaire, l. Variables affecting the level of general symptoms were sex, the total time of VDT operation per day, type of typewriting, location of keyboard, illumination, VDT working duration, the time of VDT operation without rest. 2. Variables affecting the level of eye symptoms were sex, the total time of VDT operation per day, type of typewriting, VDT working duration, illumination, method of eye-resting. 3. Variables affecting the level of musculoskeletal symptoms were sex, the total time of VDT operation per day, the time of VDT operation without rest, illumination. Conculsions : In order to protect workers from VDT syndrome, it is urgently required to implement standard management recommendations including restriction of VDT working hours and allowance of more sufficient resting time for VDT workers.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.1
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• pp.59-64
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• 2015

This study focuses on the dimensions of tractor seat, which is one of the important link between the tractor and the operator based on ergonomic approach in the design process. 7 anthropometric data sets were introduced from Korean and US anthropometric database for adult male and female including length of buttock to back of knee (sitting), height of lowest point of shoulder blade (sitting), underside elbow height (sitting), and so on. Design factor for the tractor seat included dimensions of seating surface, dimensions of backrest surface, and the location of armrest. The shape of spinal curve and clothing correction should be also considered during the design process. The result of this study can be used as a guideline for the design process of tractor seat.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.1
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• pp.143-151
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• 2007

The effects of job stress factors on psychological job stress and job satisfaction levels of school dietitians were evaluated. Questionnaires were distributed to 163 elementary school foodservice dietitians in the Seoul and Incheon area. Statistical data analysis was completed using the SPSS program. The highest stress factor was the importance of the job followed by role ambiguity, autonomy and identity, communication and participation. When dealing with job stress, the subjects showed improved and positive behaviors when communicating and participating with each other. The analysis of the relationships between job stress factors and job satisfaction revealed that the importance of the job had a negative effect on jog satisfaction. while role conflict and overload, personal relationships, and experience accumulation had positive effects. Ample occupational experience and background had highly positive effects on school dietitians' job satisfaction level whereas negative results were shown concerning circulated appointments(p<0.01). Based on these results, we suggest that role conflict and overload should be reduced in order to lower job stress levels and enhance job satisfaction levels.

• Journal of the Ergonomics Society of Korea
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• v.20 no.2
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• pp.71-82
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• 2001

Twisting posture in lifting tasks has been identified as a risk factor of low back pain. However, it has been usually estimated in terms of compressive stress or muscular activity. Thus, this study was conducted to predict the influence on muscular fatigue during lifting simulation. Fifteen young and healthy subjects were recruited and performed isometric trunk exertions during upright standing, two-level flexions and five-level asymmetric twisting conditions. EMG signals from five primary trunk muscles in right part of body were collected during 20sec for 45 different lifting conditions. RMS(root mean square) and MPF(mean power frequency) parameters were used to analyze the EMG signals. Twisting postures were significant in right erector spinae(ERSR), right latissimus dorsi(LATR), right internal oblique(INOR) for muscular activities. Especially, when trunk was $30^{\circ}$ CCW twisting posture. ERSR and INOR activities increased respectively by 11% and 3%. Regarding the trunk muscle fatigue, we found that MPF shifts in twisting posture increased 2.3 and 2.6 times for ERSR and INOR muscles respectively. Therefore, It is probable for workers to suffer from low back disorders when they were exposed to a extreme twisting posture during prolonged lifting. This study suggests NIOSH(National Institute for Occupational Safety and Health) lifting equation needs the time-duration multiplier in addition to asymmetric multiplier.

• Journal of Agricultural Extension & Community Development
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• v.18 no.4
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• pp.861-877
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• 2011

The purpose of this study is to survey job stress and Musculoskeletal Disorder(MSDs) of workers in small plants with agricultural products. The subjects were comprised of 69 workers participated in "Helping the rural women to get the small businesses" project. The questionnaire surveys were Korean Occupational Stress Scale(KOSS), and Legal Risk Assessment of Musculoskeletal Disorders(KOSHA CODE H-30-2003). As a result of the survey, scores of KOSS 8 sub-items except for job demand were similar to that of Korea workers. Prevalence of MSDs symptoms of small plants workers was high percent (44.9%). And the rate according to kinds of product was significant difference at neck (p<0.01), lumbar (p<0.01), and leg (p<0.01). There was no significant difference between view person sign of MSDs and non MSDs according to sex, year, the number of workers, working years, working time per one day, rest time per one day, and subjective working intensity, but there were significant difference between high stress group and low stress group about MSDs at interpersonal conflict(p<0.05). Job stress and MSDs were important factor to workers of small plants producted agricultural products. Therefore, starting a business with small plats, workers consider interpersonal conflict and body part showing MSDs.

• Journal of the Korea Safety Management & Science
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• v.16 no.2
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• pp.81-90
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• 2014

Flexible production system has been expanded to all sectors of economy with the change of labor market and diversification of employment. The unstable employment with irregular work has replaced stable employment with regular work. This study has investigate the impact pathway of the type of employment on health status especially ill-health symptoms experiences. Among the first Korean Working Conditions Survey data, the employee's response data was used to analyze the path way with multiple regression analysis. The result has shown the direct effect of the type of employment on ill-health symptoms experience. Indirect effect of the type of employment was found the pathway via the exposure to noise, high temperature, low temperature, dust, skin contact to chemicals, painful posture, heavy material handling, standing position, repetitive movement of hands. However the exposure to the other hazardous factors such as organic solvent, wholebody vibration, radiation, lifting people, infectious materials were not influenced by the type of employment.