• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.984-987
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• 2010

본 연구는 병원 종사자들의 작업관련 자각증상 호소율의 요인들을 파악하고자 시도되었다. 자료수집은 2010년 5월 18일부터 6월 18일까지 서울 소재 2개 종합병원 종사자 157명을 대상으로 설문조사를 하였다. 연구결과 첫째, 작업관련 자각증상 호소여부는 허리의 증상호소자가 평균 19.53점으로 비증상호소자의 평균 13.06점보다 유의하게 높았다(t=9.684, p=0.007) 둘째, 운동을 안하는 군에 비해 운동을 불규칙적으로 하는 군의 자각증상 호소률은 2.18배(OR=2.183, 95%, Cl=1.362-7.420)로 유의하게 높아지는 것으로 나타났다. 따라서 작업관련 증상관리를 위한 건강증진 프로그램 개발시 이에 대한 총체적인 반영이 필요할 것으로 본다.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.3
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• pp.11-22
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• 2010

An analysis method is proposed for the transient linear or nonlinear analysis of dynamic interactions between a flexible dam body and reservoir impounding compressible water under earthquake loadings. The coupled dam-reservoir system consists of three substructures: (1) a dam body with linear or nonlinear behavior; (2) a semi-infinite fluid region with constant depth; and (3) an irregular fluid region between the dam body and far field. The dam body is modeled with linear and/or nonlinear finite elements. The far field is formulated as a displacement-based transmitting boundary in the frequency domain that can radiate energy into infinity. Then the transmitting boundary is transformed for the direct coupling in the time domain. The near field region is modeled as a compressible fluid contained between two substructures. The developed method is verified and applied to various earthquake response analyses of dam-reservoir systems. Also, the method is applied to a nonlinear analysis of a concrete gravity dam. The results show the location and severity of damage demonstrating the applicability to the seismic evaluation of existing and new dams.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.175-183
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• 2022

In this study, 46 reservoirs in South Korea were characterized based on heavy metal concentration in sediments. We analyzed the relationship between heavy metal concentrations, physicochemical water quality and hydromorphological factors in each reservoir. Study reservoirs were classified into five groups of reservoirs, by hierarchical cluster analysis based on the similarities of heavy metal concentration. Group 1 had the most severe sediment heavy metal contamination among the groups, whereas Groups 2 and 3 showed low levels of heavy metal contamination. Group 4 displayed high value of Ni, and Group 5 showed high contamination of Pb, Cu, Cr, Ni, and Hg. Groups 1 and 5, which had high concentration of heavy metals in sediments, showed a high density of mines in the catchment of reservoirs. Heavy metal concentration was high in reservoirs with large capacity or the ones located at higher elevation, and also highly related with number of mines in the catchment of reservoir. This study can contribute to the systematic management of sediment heavy metals in reservoirs.

• Journal of Preventive Medicine and Public Health
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• v.22 no.4 s.28
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• pp.506-517
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• 1989

Two hundred and fifty teachers of special school (for the disabled) and 414 elementary school teachers were selected for the targets in order to compare their degrees of fatigue symptoms and to find what kind of ralationship is between subjective symptoms of fatigue and pH is the saliva. It was 30 minutes before their closing hours on April 21th, 1989 that their physical, mental and neuro-sensory symptoms and salivary pH were examined. The test results are summarized as fallows : It is observed that an interrelation between subjective fatigue and pH in their saliva shows a significant relationship between physical and neuro-sensory symptoms in a sense of statistics. The rate of subjective fatigue complained by the special teachers is higher than that by the elementary teachers. In the case of salivary pH, the special teachers' is as a whole lower than the elementary teachers'. The complain rates in each item, checked, of special teachers are generally higher than those of the elementary teachers. It is in the mental symptom related item that there are many sub-items which show significant difference. According to the average of salivary pH based on the degrees of complained symptoms shown in the pH related items, the salivary pH of the group with complained symptoms is lower than that of the group without complained symptoms. In the rate of complaints, by sex, both sexes of the special teachers show high ones, but salivary pH is low. The complain rate of mental symptoms shown by female group from the special teacher Is significantly higher(p<0.05). By age, the group in their thirties from the special teachers show the higher complain rate of mental symptoms (29.3%) and the lower salivary pH (p<0.05) than that (15.1%) of the elementary teachers belonging to the same age catagory. However, the special teachers in their forties show the lower complain rate of physical symptoms that of the elementary teachers (p<0.05). From the viewpoint of their working years, the special teachers below 14 years and elementary teachers above 15 years in their career show high complain rates. Among those who belong to the catagory of 10-14 working years, the special teachers show the higher complain rate of mental symptoms than that of their counterparts. In the case of the salivary pH, the special teachers of all working-year catagories show the higher pH than that of the elementary teachers. But there is not significantly difference. From the viewpoint of sleeping hours in the previous night of the questionaire surveyed, among those who slept for over 7 hours, the special teachers show the higher complain rate of mental symptoms with a significant difference, but the lower salivary pH than that of their counterparts. From the viewpoint of their marital status, existence of disease history, the special teachers show the higher complain rate of subjective fatigue, but the lower salivary pH than that of the elementary teachers respectively. According to the above results, the special teachers generally show the higher complain rate of subjective fatigue, the lower salivary pH, and the higher complain rate of mental symptoms. To prevent the possible accumulation of mental fatigue of the special teachers, ways and means to make use of leisure time, recreational facilities are necessarily provided. Since the degree of fatigue and salivary pH have a correlation to some extent, it is necessary that further continuous studies on the correlation between the degrees of fatigue and salivary pH should be pursued.

• Journal of Wetlands Research
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• v.20 no.2
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• pp.173-180
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• 2018

The utilization of TOC(Total organic carbon), a new environmental standard, was evaluated for 30 lakes in the Nakdong River Basin, which is used for drinking and agricultural usage. The active use of water resources begins with securing satisfactory water quality. Since this allows people and nature to maintain stability of quality, water quality standards are being tightened to ensure good water quality. In order to improve the pollution level of organic matter in lakes in the living environment, it is important to use the appropriate organic substance index. The relationship between the newly introduced TOC and the existing COD(Chemical oxygen demand) in the targeted lake was positively correlated with the possibility of replacing the TOC with COD. However, the environmental grade standard using TOC is better than the environmental grade standard using COD, so it has the same effect as that of the grade of water quality using TOC as an organic substance factor. This indicates the limitation of TOC to directly replace existing COD when trying to determine or improve the quality level using organic indicators of lakes. Therefore, in order to secure the qualitative safety of the lake, it is required to strengthen environmental standards of TOC in terms of water quality grade. In addition, the correlation between TOC and COD shows a great difference depending on the utilization characteristics of the lake. This requires clear scientific identification, and it requires continuous monitoring of COD that has been used to accumulate indicators of lake organic matter.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.390-397
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• 2021

The time series data of rotifer community focusing on the species number and total density were collected from 29 reservoirs located at Jeonnam Province from 2008 to 2016 quarterly. The reservoirs had similar weather condition during the study period, but their sizes and water qualities were different. To analyze the temporal dynamics of rotifer community, the medians, ranges, outliers and coefficient of variation (CV) value of rotifer species number and abundance were compared. For the temporal trend analysis, time series of each reservoir data were compared and clustered using the dynamic time warping function of the R package "dtwclust". Small-sized reservoirs showed higher variability in rotifer abundance with more frequent outliers than large-sized reservoirs. On the other hand, apparent pattern was not observed for the rotifer species number. For the temporal pattern of rotifer density, COD, phytoplankton abundance fluctuation, and cladoceran abundance fluctuation have been suggested as potential factor affecting the rotifer abundance dynamics.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.124-138
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• 2003

This paper aimed to analyze the relationship between alga3 bloom patterns and hydrological, limnological data which were collected from major reservoirs in Korea for 8 years (1990${\sim}$1997). Water temperature of river-type reservoirs showed wider seasonal fluctuations than that of lake-type. pH of lake-type reservoirs was low in winter season but high in summer season. In contrast, river-type reservoirs showed high pH in spring and autumn seasons as well, and very low in summer season. COD of lake-type reservoirs and Paldang reservoir was lower (2${\sim}$3 mg/L) than that of Geumgang and Nagdonggang reservoirs (6${\sim}$9 mg/L). Dissolved oxygen (DO) of river-type reservoirs was higher than that of lake-type reservoirs. Seasonal fluctuation pattern of DO saturation in river-type reservoirs was high (80 ${\sim}$100%) and remained relatively constant whereas lake-type reservoirs showed the highest level (93%) in late spring or early summer, which gradually decreased entering winter season(46${\sim}$06%). And monthly variation of DO saturation showed inverse proportion to water volume in lake-type reservoirs. Nutrients concentration in river-type lake is higher than lake-type. Seasonal fluctuation of nutrients (T-N, T-P) in lake-type reservoirs was relatively small than that of river-type reservoirs. Annual mean N/P mass ratio of lake-type reservoirs was higher than that of river-type. Transparency tended to related with the suspended solid concentration in river-type reservoirs. Algal bloom of lake-type and river-type reservoirs occurred at any time except rainfall and winter periods. And it dominated in summer and early autumn, respectively. Algal bloom of river-type reservoirs was higher than that of lake-type. Relationship between rainfall and chlorophyll- a in lake-type reservoirs was relatively high, however river-type reservoirs showed insignificant.

• Journal of the Speleological Society of Korea
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• no.64
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• pp.49-59
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• 2004

This study area that is big Lake by Pauldang-Dam on 1973 that is together North Han-River, South Han-River, and GyaungAn-River. So, Lake flow slow, have many deposit-silt, sand, Pebble etc. Large Land is submerge. in result, Lacustrin wetland became. Water sources are precipitation, river, aquifer. But this wetland is made by dam's water control plan.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.324-328
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• 2008

댐으로 인한 인공호수는 주위의 지역사회는 물론 타지역으로부터의 친수공간으로 활용될 수 있는 충분한 여건을 가지고 있음에도 불구하고 여러 가지 법적인 규제로 인해 극히 제한적으로 활용되고 있는 실정이다. 본 연구는 댐 호소의 관광자원화를 통한 친수공간의 확보와 국민복지증대 및 지역사회의 경제발전을 함께 도모할 수 있는 방안을 모색하였다. 만약 댐 호소에 대한 규제완화가 환경적인 영향이 크지 않고 경제적인 가치가 크다면 현 제도의 개선은 국민후생의 증대효과와 비점오염원의 관리를 통해 수질개선효과에 영향을 미칠 수 있음을 제시하였다.

• 건강소식
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• v.37 no.3
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• pp.32-33
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• 2013

따뜻한 봄바람이 불어오면 춘곤증을 호소하는 사람들이 늘어난다. 피곤함과 졸음을 호소하고, 일상생활이나 업무활동에서 의욕과 집중력을 잃고 쉽게 짜증을 내기도 한다. 뿐만 아니라 식욕부진, 소화불량, 현기증 등도 대표적인 춘곤증의 증상이다.