• 소성∙가공
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• 제1권1호
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• pp.42-51
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• 1992

The ring compression test has been widely employed as an experimental means to determine the friction factor. The calibration curves are obtained by the rigid-plastic finite element analysis for various work-hardening exponent and strain-rate hardening exponent. The effects of work-hardening exponent and strain-rate hardening exponent are thoroughly studied and discussed from the finite element computation. The change of friction factor during height reduction in ring compression is also discussed. Then, the method to estimate the change of friction factor during ring compression is proposed.

• 한국안전학회지
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• 제31권3호
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• pp.96-101
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• 2016

Previous literature has been investigated various aspects of accident occurrence and prevention in construction field. However, those studied were limited in that they only focused on the death accident without considering the loss time accident. Based on this, the goal of current study was to investigate the nature of the loss time accident, and compare the results with the death accident. Results showed that 1) the occurrence rate of death accident was significantly higher in the form work, temporary work, and steel frame work; 2) the temporary work showed significantly higher occurrence rate of the loss time accident and the death accident as compared to others; 3) ratio of the loss time accident to the death accident in domestic construction field was 50:1; 4) fall accident showed biggest occurrence rate in both the loss time accident and the death accident; and 5) more that 80% of workers in both the loss time accident and the death accident was between 41 and 65 years old.

• 한국안전학회지
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• 제28권5호
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• pp.78-82
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• 2013

The purpose of this study is to review the labor force partitpation rate and work environment characteristics of female workers to provide basic information for establishment and implementation of effective policies related to accident prevention and workers health protection for female workers. It was analyzed employment status, work environment and injuries and illnesses based on economic activity census results, compensation of industrial injury and the second working condition survey. According to economic activity census results, female labor force participation rate has been steadily increased, whereas male labor force participation rate has been decreased since 1970. Industrial accident rate has been declined in male workers but that in female workers has been steadily increased even though male workers were higher accident rate than female workers. It was evaluated that female workers are vulnerable to industrial injuries and illnesses in the aspect of their working environment and employment status. Also, Substantial differences between female and male workers in occupational exposure patterns, occupational disease and occupational environments were observed. Therefore it was recommended that special care programs for female workers such as a specialized monitoring and management program should be introduced in the near future.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2006년도 추계학술발표대회 논문집
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• pp.128-132
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• 2006

Low-k wafer engraving process has been investigated by using UV pico-second laser with high repetition rate. Wavelength and repetition rate of laser used in this study are 355nm and 80MHz, respectively. Main parameters of low-k wafer engraving processes are laser power, work speed, assist gas flow rate, and protective coating to eliminate debris. Results show that engraving qualities of low-k layer by using UV pico-second pulse width and high repetition rate had better kerf edge and higher work speed, compared to one by conventional laser with nano-second pulse width and low repetition rate in the range of kHz. Assist gas and protective coating to eliminate debris gave effects on the quality of engraving edge. Total engraving width and depth are obtained less than $20{\mu}m$ and $10{\mu}m$ at more than 500mm/sec work speed, respectively. We believe that engraving method by using UV pico-second laser with high repetition rate is useful one to give high work speed of laser material process.

• 한국건설관리학회논문집
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• 제15권4호
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• pp.3-10
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• 2014

소득수준이 높으면 이와 함께 사회 경제 문화적 기대수준도 함께 향상되는 것이 일반적이며, 산업안전에 대한 기대수준도 함께 높아질 것이다. 그러나 우리나라는 소득수준은 그동안 많이 향상되었으나, 산재사망률은 OECD국가 중 가장 높은 수준이며 산재사망이 지난 10여년간 전혀 줄어들고 있지 않고 있다. 본 연구는 우리나라의 소득수준 대비 산재사망률을 관련 국가들과 비교하고 그 차이점을 분석하여 근로자 중심의 산재예방 대책의 문제점을 파악하고 이에 대한 적절한 대책을 제시하는 것을 목적으로 하여 진행되었으며, 이를 위해 소득반영 산재사망지수를 제시하였다. 그 결과 우리나라의 경우 비교국가 중에 그 수치가 가장 높게 나타났으며, 그 원인에 대한 분석의 일환으로 산업재해에 대한 법집행실적에 대한 비교를 한 결과 위반 사업주에 대한 법집행에 중점을 두는 영국의 경우와는 달리 우리나라의 법집행 실적은 상대적으로 낮은 편으로 나타나 건설공사의 안전성 향상을 위해서는 향후 법집행 강화의 필요한 것으로 나타났다.

• 대한방사선기술학회지:방사선기술과학
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• 제45권4호
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• pp.355-363
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• 2022

This study was to investigate the prevalence rate of musculoskeletal disorders in relation to general characteristic factors, living environment factors, and work environment factors for sonographer's. For the response questions, the guidelines for musculoskeletal burden work were used. For statistical analysis, SPSS 26.0 version was used. For the common body parts of the sonographer's who responded, the prevalence was investigated by dividing the group into a group with high pain or discomfort and a group with low pain or discomfort according to the degree to which they experienced symptoms during the past 12 months. Multiple logistic regression analysis was used to determine the variance inflation factor(VIF), odds ratio (OR) and corresponding 95% confidence interval (CI). A p-value of <0.05 was considered statistically significant. As a result, housework hours, examination history, regular physical activity, number of patient examinations per day, and sitting posture were investigated as variables for rate musculoskeletal disorders. The sonographer's occupational group was found to have a high prevalence rate of musculoskeletal disorders like various other occupational groups. Based on the results of this study, it is judged that musculoskeletal disorders can be reduced by recognizing musculoskeletal disorders and improving work environment factors.

• 한국직업건강간호학회지
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• 제3권호
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• pp.5-20
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• 1993

This study was aimed to investigate the actual condition of the performance of the occupational health nursing services, and to analyze a main cause which affects on the execution of its duties for occupational health nurses in occupational group health service. It had been surveyed by responsed data from the 105 respondents out of 180 persons. The results were as follows : 1. In performance of occupational health nursing services by the number of assigned plant, participation rate of health examination tended to significantly increase with decreasing the number of assigned and it was observed that the visiting rate of every month was also significantly higher on touring inspection of work plant, recommendation of facility improvement for work environment, understanding the modification of manufacturing process, and inspection of welfare and sanitation facilities. 2. While they executed their nursing services according to duration of service, the more, their duration of service was, the higher, participation rate of health examination, health check in returning to work for injured workers, talk with other health managers on promoting welfare, service evaluation for a year plan, record of health statistic, and experience of first aid service were. And it was found out that the visiting rate of every month was also significantly higher on touring inspection of work plant. 3. In regard to occupational health nursing services by age, the participation rate of health examination and the experience of first aid service were significantly higher as the age increased. And also the visiting rate of every month was significantly higher on touring inspection of work plant, compared with young ones. 4. In performance of occupational health nursing services by the time required visiting plant, The shorter, the time required visiting plant was, the higher, the visiting rate of every month was, on time of health consultation for diseased workers, and inspection of welfare and sanitation facilities. 5. The subjects of health education were mostly liver disease and occupational hearing loss and video tape was used mostly in health education, monthly health education was the highest in 1-3 times(74.5%) and its duration was the highest in about 60 minutes(33.3%). 6. Vaccination of hepatitis among the specific health services was the highest accounting for 64.7%.

• Journal of Biosystems Engineering
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• 제35권5호
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• pp.357-365
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• 2010

Workers in the agricultural industry have been exposed to many work-related musculoskeletal disorders. So, our objectives in this study were to measure and analyze worker's physiological bio-information to reduce musculoskeletal disorders in relation to agricultural works. We investigated worker's bio-information of physiological signals during the repeated lifting work such as body temperature, heart rate, blood pressure, physical activity, and heart rate variability. Moreover, we analyzed the workloads of lumbar spine during the repeated lifting work using the 3-axis acceleration and angular velocity sensors. The changes of body temperature was not significant, but the mean heart rate increased from 90/min to 116/min significantly during 30 min of repeated lifting work (p<0.05). The average worker's physical activity(energy consumption rate) was 206 kcal/70kg/h during the repeated lifting work. The workers' acute stress index was more than 80, which indicated a stressful work. Also, the maximum shear force on the disk (L5/S1) of a worker's lumbar spine in static state was 500N, and the maximum inertia moment was 139 $N{\cdot}m$ in dynamic state.

• 반도체디스플레이기술학회지
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• 제6권1호
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• pp.11-15
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• 2007

Low-k wafer engraving process has been investigated by using UV pico-second laser with high repetition rate. Wavelength and repetition rate of laser used in this study are 355 nm and 80 MHz, respectively. Main parameters of low-k wafer engraving processes are laser power, work speed, assist gas flow, and protective coating to eliminate debris. Results show that engraving qualities of low-k layer by using a laser with UV pico-second pulse width and high repetition rate had better kerf edge and higher work speed, compared to one by conventional laser with nano-second pulse width and low repletion rate in the range of kHz. Assist gas and protective coating to eliminate debris gave effects on the quality of engraving edge. Total engraving width and depth are obtained less than $20\;{\mu}m$ and $10\;{\mu}m$ at more than 500 mm/sec work speed, respectively. We believe that engraving method by using UV pico-second laser with high repetition rate is useful one to give high work speed in laser material process.

• 설비공학논문집
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• 제29권4호
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• pp.185-194
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• 2017

Currently, in comparison with other architectural estimations, the estimation work regarding building mechanical-service systems is time-consuming, and the process is continuously becoming more difficult because of the increased usage of the attached piping materials such as fittings and hangings in addition to their complicated construction processes. To improve this problem, the Korean authority provides a simple estimation method for the attached-material rate regarding the main piping material, which is the most time-consuming work in the architectural-mechanical estimation. However, to be an applicable method on construction sites, a proper conversion rate of the attached-piping material is still required for the proposed method regarding building usage and working types. Therefore, the purpose of this research is the calculation of the rate of the attached-piping materials such as the fittings and supports through the building of the mechanical-service work types of mechanical rooms, air conditioning, domestic water and hot-water supplies, and the drain-, vent-, and gas-piping work in office buildings that have been designed after 2010.