• 대한치과기공학회지
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• 제18권1호
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• pp.73-94
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• 1996

This study was aimed for evaluating the validity of relative-productivity index on the basis of working hour(RPHW index) designed by author as new productivity index and drawing up a plan of bettering productivity to cope with financial difficulty of dental laboratories. Fortyeight dental laboratories extracted by cluster-sampling method form all the dental laboratories in Seoul were subjected for this study. And in each of them, the term of establishment which was divied into three group as short-term, mid-term and long-term group, the scale of dental laboratory which as divided into two group by number of dental technician as small-scale group and large-scale group, the salary system which was composed of salary criteria, pay according to ablility criteria and collectiveagree, the salary level, simple labor productivity index(SLP index), relative-productivity index on the basis of worker number(ROWN) and relative-productivity index on the basis of working hour(RPWH index) were surveyed through the self-administractive questionaires. The results as follows : Most of dental laboratories(93.6%) were managed by non-professional managers. The establishment rate per year of dental laboratory was the increase. The mean number of employees of dental laboratories was $7.00{\pm}3.90$ person. The ratio of smallscale group(under the 5 employees) was 42.6% and as the term of establishment was shorter, the ratio of small-scale group was higher. The mean establishment area of dental laboratories was $24.49{\pm}10.97$ unit and the mean establishment area per head of dental laboratories was $4.05{\pm}3.90$ unit. The estabilshment area and area per head were not significantly associted with the term of establishment, but as the term of establishment was shorter, the estabkishment area per head was slightly wider. The establishment area per head in small-scale group was significantly wider than large-scale group(over the 6 emplayees) The salary criteria(54.4%), pay according to ability(79.2)m ability criteria(77.1%) and collectiveagree(79.2%) as salary systems were used in the most of all dnetal laboratoies. The all salary systems were not significantly associated with the term of establishment and the scale of dental laboratories. The monthly mean salary level of dental laboratoies was $125.64{\pm}31.06$ milion won. The monthly salary level was not significantly associated with the term of establishment and the scale of dental laboratores. But the monthly salary level in the short-term group and the small-scale group were slightly lower than others. The SLP index, the RPWN index and the RPWH index of dental laboratories were $132.16{\pm}48.41$, $382.41{\pm}128.76$ and $76.06{\pm}25.11$, respectively. The SLP, the RPWN and the RPWH of dental laboratories were not significantly associated with the term SLP, the RPWN and the RPWH of dental laboratories were significantly associated with the area of dental laboratory and the salary level. Except for only the association salary criteria among salary system with RPWH of dental laboratories, all other salary system were not associated with the SLP, the RPWN and the RPWH of dental laboratories.

• Journal of Korean Neurosurgical Society
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• 제63권5호
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• pp.623-630
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• 2020

Objective : A primary degenerative sagittal imbalance has been considered because of unique lifestyles such as the prolonged crouched posture during agricultural work and performing activities of daily living on the floor. Previous papers have reported that sagittal imbalance disease is often seen distinctly in the farming districts of "oriental" countries such as Korea and Japan. However, this finding was only evaluated with the use of X-ray, and other factors such as magnetic resonance imaging (MRI), muscle volume, compression fracture, and laboratory results were not considered. Thus, using these, we evaluate the agricultural work-associated factors for Korean elderly spinal sagittal imbalance. Methods : We recruited 103 Korean participants who had a sagittal vertical axis (SVA) of >5 cm in this Korean Elderly Sagittal Imbalance Cohort Study. The following were evaluated : radiological parameters, MRI, compression fracture, vitamin D, parathyroid hormone, C-terminal telopeptide, osteocalcin, bone mineral density and muscle fatty change, muscle volume, and health-related quality of life from patients' survey. Moreover, in this survey, the farmers' annual working hours were investigated. Subsequently, we analyzed the associated factors for spinal sagittal imbalance depending on occupation. Results : A total of 46 participants were farmers, and the others were housewives, sellers, and office workers. The farmer group had more SVA (141 vs. 99 mm, p=0.001) and pelvic tilt (31° vs. 24°, p=0.004) and lesser lumbar lordosis (20° vs. 30°, p=0.009) and thoracic kyphosis (24° vs. 33°, p=0.03) than non-farmer group. A significantly positive correlation was noted between the working hour and SVA in the farmer group (p=0.014). The visual analogue scale score for back pain (8.26 vs. 6.96, p=0.008) and Oswestry Disability Index (23.5 vs. 19.1, p=0.003) in the farmer group were higher than that in the non-farmer group, but the Short Form-36 score was not significantly different between the two groups. The Mini-Mental State Exam score was significantly lower in the farmer group than in the non-farmer group (24.85 vs. 26.98, p=0.002). Conclusion : The farmer group had more sagittal imbalance and back pain in proportion to the working hours even though the muscle and bone factors and general laboratory condition were not significantly different between the two groups. These results supported that the long hours spent in the crouched posture while performing agricultural work were a risk factor for severe sagittal imbalance.

• 한국산업보건학회지
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• 제32권4호
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• pp.435-448
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• 2022

Objectives: As the time spent wearing masks has increased with spread of COVID-19, various research related to masks have been reported. However, there are still few experiments on the physiological response of the body to wearing industrial dust masks in South Korea. Considering the actual working hours at the work site, it is necessary to investigate the comfort of industrial dust masks. Therefore, this study aims to confirm the change in subjective discomfort level according to the wearing time for industrial dust masks in South Korea that have been certified for safety by KCS. Methods: This study evaluated subjective discomfort level over four hours. The experimental conditions were five types: not worn (control group), special grade, first grade, second grade (with valve), and second grade (without valve). The subjective discomfort levels were classified for breathing, warmth (body and face) and wetness (body and face). Subjects recorded their discomfort level on a checklist every one hour. Results: In special grade and second grade (without valve), the discomfort level in terms of breathing, warmth (face), and wetness (face) was significantly higher than that of the control group. However, the effects of all kinds of industrial dust masks on the discomfort level in the body were low. Conclusions: Since this study was conducted on subjects working in an office with a comfortable working environment, it is difficult to apply it to workers at actual industrial sites. However, it is considered meaningful as the first clinical study to evaluate the subjective level of discomfort over a long time for domestic industrial dust masks that have been certified for safety by KCS.

• Safety and Health at Work
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• 제2권1호
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• pp.39-51
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• 2011

Objectives: This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. Methods: The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologic and reproductive toxicities to evaluate the overall health effect for semiconductor industry workers. With respect to monitoring, active and passive sampling techniques were introduced. Eight-hour long-term and 15-minute short-term sampling was conducted for the area as well as on personal samples. Results: The results of the measurements for each substance showed that benzene, toluene, xylene, n-butyl acetate, 2-methoxy-ethanol, 2-heptanone, ethylene glycol, sulfuric acid, and phosphoric acid were non-detectable (ND) in all samples. Arsine was either "ND" or it existed only in trace form in the bay air. The maximum exposure concentration of fluorides was approximately 0.17% of the Korea occupational exposure limits, with hydrofluoric acid at about 0.2%, hydrochloric acid 0.06%, nitric acid 0.05%, isopropyl alcohol 0.4%, and phosphine at about 2%. The maximum exposure concentration of propylene glycol monomethyl ether acetate (PGMEA) was 0.0870 ppm, representing only 0.1% or less than the American Industrial Hygiene Association recommended standard (100 ppm). Conclusion: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.

• 한국산업보건학회지
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• 제23권4호
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• pp.348-355
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• 2013

Objectives: In working environment measurement, sampling is an important stage for obtaining reliable result as analysis. A personal air sampling pump is one of the most fundamental and important element in the work environment measurement, but it remains at the level of calibrating the flow rate of the pump before and after sampling. There is no checking whether the flow rate set at the initial stage would be hold during sampling. The purpose of this study was to develop a method to evaluate the flow rate performance of particulate sampling pump with three-pieces cassette holder containing filters commonly used to sample particulate. Materials and methods: We tested back pressure of particulate sampling pumps commonly used in Korea with three-pieces cassette holder containing various filters, and tried to find out the combination conditions of filters in accordance with back pressure required by ISO standard 13137. Results: We found out the matrix of sampling media such as three-pieces cassette holder containing filters applicable to the pressure drop required by the ISO standard for evaluating the flow rate stability under increasing pressure drop and long term(8 hour) performance. Conclusions: This evaluation method using sampling media matrix for checking flow rate stability proposed by this study could be very useful tool to find out good performance pumps before sampling.

• 한국분말재료학회지
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• 제12권3호
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• pp.167-173
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• 2005

Production of weakly agglomerated nanopowders with the characteristic size of about 10 nm and a narrow particle size distribution is still a topical problem especially if the matter is an acceptable output (>50 g/hour), a high purity of the final product, and a low (energy consumption. The available experience and literature data show that the most promising approach to production of such powders is the evaporation-condensation method, which has a set of means for heating of the target. From this viewpoint the use of pulsed electron accelerators for production of nanopowders is preferable since they allow a relatively simple adjustment of the energy, the pulse length, and the pulse repetition rate. The use of a pulsed electron accelerator provides the following opportunities: a high-purity product; only the target and the working gas will interact and their purity can be controlled; evaporation products will be removed from the irradiation zone between pulses; as a result, the electron energy will be used more efficiently; adjustment of the particle size distribution and the characteristic size of particles by changing the pulse energy and the irradiated area. Considering the obtained results, we developed a design and made an installation for production of nanopowders, which is based on a hollow-cathode pulsed gas-filled diode. The use of a hollow-cathode gas-filled diode allows producing and utilizing an electron beam in a single chamber. The emission modulation in the hollow cathode will allow forming an electron beam 5 to 100 ms long. This will ensure an exact selection of the beam energy. By now we have completed the design work, manufactured units, equipped the installation, and began putting the installation into operation. A small amount of nanopowders has been produced.

• 대한토목학회논문집
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• 제28권1D호
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• pp.67-72
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• 2008

건설기계는 건설사업의 성공적인 수행을 위한 중요한 요인이다. 그리고 건설기계에 소요되는 비용이 건설공사비에서 차지하는 비중이 크다. 따라서 건설기계 비용의 산정은 건설계획 단계에서 중요한 업무이다. 이를 위해서 우리나라는 표준 품셈에 제시된 건설기계 시공능력 산정식을 이용하여 건설기계의 시간당 작업량을 계산하는 방식을 활용하고 있다. 그러나 건설기계의 성능은 개선되고 있으나 시공능력 산정식에서 활용되고 있는 작업효율은 이를 반영하지 못하는 실정이다. 이에 본 연구는 유압식 백호, 로우더, 덤프트럭을 대상으로 현장실사를 통해 작업효율을 실측하였다. 그 결과 백호와 로우더는 현재 활용중인 작업효율보다 현장실사 값이 높게 나타났으며, 덤프트럭은 낮게 나타났다. 본 연구결과를 바탕으로 건설기계의 작업효율 표준 산정식에 대한 정의가 수립되어야 하며, 체계적이고 장기적인 조사를 거쳐 작업효율의 개정이 필요할 것으로 사료된다.

• Journal of Preventive Medicine and Public Health
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• 제30권2호
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• pp.293-307
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• 1997

In Korea, sudden deaths of middle-aged and older male workers who are the responsible persons at home as well as workplace, have aroused social concern. Besides, U. N. has reported recently that mortality of Korea male in 40-50's was one of the highest among newly developed countries in 1992. Not much is, however, known about the nature of the work contributing to the mortality of different groups of workers. Therefore, this study was done to examine mortality of public servants, comprising about 5% of all the employed in Korea, according to their job titles and grades. The datas of 1753 official deaths, comprised 323 (only disease-oriented deaths) applicants of survivors' compensation, were used to examine age-adjusted Standardized Mortality Ratios(SMRs) according to their job titles, grades, tenures and cause of deaths. Controlling age and sex difference was conducted using 26,950,481 general population, 95,340 general deaths and 864,560 working public servants. All the groups were aged 20-64, who were being observed January - December in 1993, at the same time. Results and discussions are as follows. 1. SMRs standardized by general population was significantly low (SMR 44.9 CI 42.8-52.7) for all job titlses. Of public servants, 90.0% was graduated from high school, although 17.5% in general population. The distinction of social status such a education may produce a strong healthy worker effect. Besides, SMRs for different tenure groups showed a steady increase as tenure increases. This suggests that the magnitude of healthy-worker effect may be greater with increasing tenures. 2. SMRs standardized by own public servants was significantly elevated for work-men(SMR 121.0, CI 110.2-132.6) in solitue. When SMRs for different grade, of work-men was examined, 9th(SMR 124.2, CI 104.4-146.7) and 10th(SMR 137.9 CI 120.8-156.8)grade, lower grade in workmen, showed significantly elevated SMRs. Of workmen, 57.0% were graduated from high school and 50.1% in 9th grade, as well. These mean that low economic states made up social class, education may increase mortality rate. 3. Of SMRs according to all causes of death, only policemen on 'cause of death related hypertensive disease'(SMR 282.5, CI 121.6-556.7) was significantly high except for' cause of death related other signs, symptoms and ill-defined conditions'. 4. When SMRs on cause of death related hypertensive disease for different grade of policemen was examined, senior policemen(SMR 241.9), in charge of the front service, showed elevated SMR, in spite of statistical no significance. Especially, the working hour of senior policemen is quite long and also the work schedule is even more irregular for policemen. The results of this study showed that mortality for different jobs differed, and it differed also for different grades in the same job. This difference in mortality may reflect the difference in the nature of job contents, and further studies are warranted to elucidate which job characteristics are responsible.

• 한국병원경영학회지
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• 제15권4호
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• pp.191-222
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• 2010

Revisioned labour law was confirmed by vote of National Assembly on 1st January 2010. Under revisions labour law the necessity was expressed to reconstruct and change the relationship between labour and management in hospital. This study was described to investigate the operational statement of labour union in general hospital and to investigate how the labour policy would be change and which form would be appear in labour union in hospital. The survey results which was operated targeting labour managers in hospital were as follows ; first, in the possibility of plural labour unions establishment, university hospital labour managers forecasted the possibility as high. but non-university hospital labour managers forecasted the possibility as low. second, even though the plural union labours would be established in hospitals there would be no difficulties in collective bargaining between labour and management. third, the labour union activities would not be shrink even though there would be wage pay prohibition for the full-time union laboures. As the wage pay prohibition acted on the full-time union labours, countermeasures are required as follows; first, there is a possibility that there will be diversity in the form of full-time union labours. It is need to make the criterion of hospital about the limit of full-time labour union members. It is need to make the criterion of labour activities of non-working hour exception. It is need to cope with the diverse demands of labour union which aim to solve the financial burdens. As the plural labour unions are permitted it is need to make countermeasures as follows ; To analyze whether there is a possibility by the establishment of new labour to be plural labour unions. To establish the countermeasures in short-term aspect to make the countermeasures to cope with the establishment of plural labour unions. In long-term aspect to establish labour and management strategies. Henceforth, found on the revisions labour law, it is need to provide in hospitals as follows; first, it is need to prepare labour management policies and substitutes which suitable for plural labour union period. Second, it is need to determine concretely on the related matters of the union labours and to develop the conclusion guidelines which preparing infective criteria. Third, to examine the effects on the hospital organization by organizational forms of labour union which is weak in financial aspect.

• 한국사회정책
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• 제24권1호
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• pp.117-151
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• 2017

일-생활 균형에 대한 사회적 인식이 확산되면서, 이른바 '저녁이 있는 삶'을 위해 근로시간을 줄여야 한다는 주장이 제기되고 있다. 기존 연구들은 장시간 근로가 생활만족도를 낮추고 특정 범주의 생활시간에 부정적인 영향을 미치고 있음을 보여주었지만, 퇴근시간이 가지는 특정 시점으로서의 의미에는 주목하지 못하였다. 본 연구는 통계청의 2014년 생활시간자료를 이용하여, 어린 자녀를 둔 전일제 임금근로자 집단을 대상으로, 근로자의 퇴근시간과 일과 후의 범주별 생활시간의 관계를 살펴보았다. 퇴근시간 집단별 생활시간 구성의 차이를 분석한 결과, 이른 시간에 퇴근한 집단은 추가로 확보한 생활시간의 대부분을 가사와 돌봄에 사용하였고, 퇴근이 늦어진 근로자 집단에서는 일차적으로 가사와 적극적 여가시간을 줄이고, 퇴근이 더 늦어지면 추가로 돌봄과 소극적 여가 관련 시간을 줄이는 것으로 나타났다. 회귀분석 결과에서는 퇴근이 빠를수록 일과 후 생활에서 가사와 돌봄, 적극적 여가의 비중이 증가하였지만, 시간대에 따라서 야근 후 퇴근하는 집단에서는 소극적 여가가, 정시에 퇴근하는 집단에서는 돌봄이, 이른 시간에 퇴근하는 집단에서는 가사와 적극적 여가가 근로자의 퇴근시간과 더 분명한 부적관계를 보이는 것으로 나타났다. 퇴근시간을 앞당기는 조치는 가사와 돌봄에서의 젠더 격차 감소에 영향을 미치지만, 그 효과는 제한적이었다. 퇴근시간의 조정은 일-생활 균형의 달성에 도움이 될 수 있지만, 젠더 격차 등을 해결하기 위해서는 구조적인 제약을 줄이기 위한 노력이 병행될 필요가 있다.