• Korean Journal of Environment and Ecology
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• v.22 no.4
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• pp.420-426
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• 2008

This study compared and analyzed EPT ratio, EPT richness and EPT number(number of species and individuals) of a total of 9 selected sites individually using EPT-group of aquatic insects in Musim stream, also compared similarity ratio between the sampling sites using UPGMA(Unweighted Paired Group Method using Arithmetic average) based on analysis subsequent to species structure of aquatic insects, and compared and analyzed a functional feeding groups(FFGs) of aquatic insects based on stream order. As a result, the aquatic insect group of 2,269 individuals is classified as 71 species, 36 families, and 8 orders, and EPT ratio and EPT richness at sites 3(0.72 and 3.89, respectively) were found to be relatively higher than those at the other sites; by contrast, those at site 9(0.03 and 0.09, respectively) were relatively low. EPT number of species and individuals was found to be lowest at site 9. As a result of UPGMA analysis, the sampling sites in Musim stream were divided into three groups, including A1(site 1, 7, 8), A2(site 2, 3, 4, 5, 6) and B(site 9). According to the results of FFGs, there was not shown specific difference in the number of functional feeding groups by each sites; however, there appeared a little more shredders and scrappers in the upper and mid stream comparing to other sampling sites while collector-filterers and collector-gatherers were found to be dominant in number in the lower stream. According to this research result, the sampling sites in Musim stream were found to have an effect on not only EPT richness, EPT ratio, and EPT number but also FFGs structure.

• Journal of the Korean Geographical Society
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• v.43 no.6
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• pp.775-790
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• 2008

This study shows possibility of active fault, throughout analyzing distributional features of tectonic and fluvial geomorphology and mineral composition of fault fracture clay, at Jinbu fault-line system in Pyeongchang-gun, Gangwon Province. Fault-line valley was formed remarkably in the upper reaches of Odae River and upper reaches of Yeongok River according along Jinbu fault-line. Landforms show rectilineal distribution at right shore slopes of Odae River in Ganpyeong-ri, southern zone of Jinbu fault-line system, related to the tectonic processes, such as triangular facet, kernbut, kerncol and alluvial fan. Fault fracture clay zones were developed at 5 outcrops($jbf1{\sim}5$), located in kerncol. Particularly, jbf1 fault outcrop, developed at granite saprolite, has obvious fault plane and fault clay composed of illite and laumontite. The Jinbu Fault-line along jbf4-2-3-5 may be formed by regional compressive stress, and jbf1 fault may be suggested a tributary fault of the Jinbu fault-line formed before the late Pleistocene. The vertical displacement of the east and west blocks of the Jinbu Fault-line is estimated in $0.024{\sim}0.027m/ka$.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.05a
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• pp.249-254
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• 2003

분석에 이용된 격자망은 동곡, 고로, 미성, 병천, 효령 및 무성지점에 각각 12개, 30개, 45개, 76개, 46개 및 1265개의 조격자를 구성하였으며 하천의 수로방향 및 경사형태를 세분화하기 위하여 각 지점에 대하여 8개, 24개, 24개, 44개, 12개 및 64개의 세격자로 분할하였다. AGNPS를 이용한 첨두유량의 모의발생 결과치가 동곡, 고로, 미성, 병천, 효령 및 무성지점에서 측정값과 비교하여 각 호우사상별로 상대오차가 1.0~25.0%, 4.0~27.0%, 7.0~29.2%, 2.0~23.9%, 3.0~25.0% 및 3.6~21.0%의 차이를 나타내었다. 분석결과에서 AMCII조건에서는 관측치와 분석결과치가 유사하게 나타났으나 AMCI조건에 대해서는 상대적으로 작은 값을 보였으며 AMCIII조건에서는 다소 큰 값으로 분석되었다. SCS방법에서 제안하는 AMC조건별 CN값을 우리 실정에 적합하도록 수정 보완하기 위한 수정 유출곡선지수 $CN_{m}$ /I과 $CN_{m}$/III을 재구성하였으며, 여기에 적용되는 수정 유출 곡선지수식의 계수 a를 추정한 결과, 기왕에 발표된 연구결과와 거의 일치된 경향을 나타내었다. 제안된 수정 CN식을 이용하여 산정한 결과치와 관측치는 거의 유사하게 나타났다. AGNPS모델에 의한 유출량 산정에 있어 수문학적 토양피복형수(CN)의 결정을 위하여 선행강우량과 토양의 공극율 및 지형인자인 각 셀마다의 유역경사를 이용하여 관계식(CN =f($X_1$, $X_2$, $X_3$))을 유도하였으며, 분석 결과에서 CN이 선행강우량과 가장 밀접한 관계가 있음을 알 수 있었으며 유역경사, 토양의 공극율 순으로 나타났다..88mg/$\ell$~의 범위로 나타났다. 무태교 지점에서의 총인의 농도는 0.52mg/$\ell$~0.99mg/$\ell$~의 범위이었다. 신천에 금호강물을 혼합한 이후에도 부유물질, 생화학적산소요구량, 암모니아태 질소, 총인 등의 농도가 개선되지 않았다. 즉 금호강물의 혼합은 신천수질환경사업소에서 배출되는 방류수에 함유되어 있을 2차 오염물질의 희석이라는 이점외의 수질개선효과는 확인되지 않았다.l years and a new type of transfer crane has been developed. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results co

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.1
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• pp.127-140
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• 1988

The management of sewage and rainfall runoff becomes an emerging problem with the growth of urban communities. From the uncontrollable excess intensity or amount of rainfall, the conditions of sewer surcharge or manhole overflow could be generated in the combined sewer network where municipal or industrial wastewaters and rainfall runoff flow. The predictive model far the prevention of property and human life losses from this inundation was studied in this research. In the development of a mathematical flow model for the combined sewer surcharge and overflow, the Preissmann Slot concept and the four-point implicit method of finite difference were utilized. For the usage in personal computer, the overlapping segment method that required less memory storage was adopted. Through the simulation of hypothetical sewer network, the conservation of discharge volume was checked, and the usefulness of the Preissmann Slot was assured from the temporal distribution of discharge and depth along the sewer network. Also the possible field application for the correction of sewer diameters and slopes in the design of sewer network which has no surcharge/overflow condition was suggested.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.3
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• pp.417-428
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• 2018

The purpose of this study is to raise the necessity of ensuring sustainability of water infrastructures in economic, social and environmental sectors by using index that evaluates the sustainability centering on water supply and wastewater utilities. This study identified sub-indexes that should be stressed among different indexes in economic, social and environmental aspects and those indexes were compared by each clusters of cities. The principal component analysis was used to calculate the weights of the sub-indexes, and the k-mean cluster analysis was conducted to classify the clusters. As a result of the weighting analysis, financial independence, service revenue ratio, subsidy ratio, population coverage ratio, deterioration, stream/river ecosystem health and river water quality were found to be the major variables in assessing sustainability. Cities were then classified into two groups using the k-mean cluster analysis. The overall sustainability scored high in the economic sector was relatively satisfactory, but it was necessary to improve the environmental sustainability. The group with relatively good environmental sustainability showed low score in the overall sustainability and required improvements in the economic sector.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.76-93
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• 2013

The hydrodynamics in the Youngsan River Estuary has changed due to coastal developments such as the estuary dam and two tidal barriers. As the freshwater discharge is artificially controlled, the circulation pattern is different from those of natural estuaries and the river-born sediment supply is restricted. 3D numerical modeling system EFDC was applied to investigate the sediment transport pattern and budget in summer with river floods. The real-time driving forces and the fluvial sediment discharges from the watershed modeling were assigned for the simulation period. The size classes of sand, silt and clay were adopted based on the grain-size distribution of bottom sediments. The modeling results were calibrated and validated with the observed tides, tidal currents and suspended sediment concentrations. The suspended sediments are transported to the offshore at surface layer, whereas upstream toward the dam at mid- and bottom layers in August 2011. The characteristic estuarine circulation induced by the freshwater discharge from the dam, causes the deposition of silt-sized sediments on the whole and the sustained suspension of clay-sized sediments.

• Korean Journal of Environmental Biology
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• v.30 no.1
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• pp.39-46
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• 2012

The distributions of phytoplankton community are investigated from 29 reservoirs in Yeongsan and Seomjin River Basins, Korea. As a microalgal flora, a total of 424 species of phytoplankton were identified. They were 157 Chlorophyceae, 161 Bacillariophyceae, 39 Cyanophyceae, and 67 other algal taxa. The phytoplankton diversity were low in stream type reservoirs such as Kumho, Youngsan and Youngam Reservoirs. The population density of phytoplankton ranged from 29 cells $mL^{-1}$ to 53,161 cells $mL^{-1}$. The dominant phytoplankton species more than 20% of total standing crops were $Asterionella$ $formosa$, $Aulacoseira$ $ambigua$, $Aulacoseira$ $distans$, $Aulacoseira$ $granulata$, $Cyclotella$ sp., $Synedra$ $acus$, $Coelastrum$ $reticulatum$, $Pandorina$ $morum$, $Scenedesmus$ $arcuatus$, $Aphanothece$ $clathrata$, $Microcystis$ $aeruginosa$, $Phormidium$ sp. The concentration of chlorophyll $a$ ranged from 0.41 mg $m^{-3}$~220.72 mg $m^{-3}$, and showed highest concentration in Gaecho-je. The concentrations of TN and TP have no clear relationships with chlorophyll $a$ concentrations.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.31-39
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• 2007

Monitoring data of 48 agricultural irrigation reservoirs from 1999 to 2004 was analyzed for water quality characteristics including biochemical oxygen demand $(BOD_5)$, chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and chl-${\alpha}$. Land uses of the watersheds associated with these reservoirs were determined for residential, forest, upland, paddy and miscellaneous, and regressed against water quality characteristics. Correlation analysis showed that forest land use was negatively correlated with all the water quality characteristics implying it's beneficial effects in water quality perspectives. Other land uses including residential, upland, and paddy generally illustrated positive correlation with water quality characteristics, which indicates most human activities of the watershed could degrade water quality of the receiving water bodies. Paddy land use partially contributed to the water quality degradation in contrast to the previous studies. It might be attributed to the relatively clean water quality of the study area, where even slight pollutant loading could degrade sensitively water quality. Further investigation is recommended for the effect of proximity as well as land use portions on the water quality of receiving water body.

• Korean Journal of Ecology and Environment
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• v.45 no.3
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• pp.278-288
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• 2012

The zooplankton community of Lake Paldang, Korea, was investigated on a weekly basis from 2004 to 2006. The seasonal succession of zooplankton community structure was influenced by hydrological factors such as rainfall pattern and efflux in Lake Paldang. According to the monsoon climate, spring, fall and winter had reduced precipitation, so that zooplankton dynamics of the lake showed a typical succession pattern. In spring, small sized and faster growing rotifera rapidly increased, and copepods and cladocera noticeably increased thereafter. Rotifera dominated the zooplankton community, occupying more than 90% of total zooplankton abundance. Among rotifera, Keratella cochlearis was extremely dominant in spring. Copepoda were mainly present as Copepodid and Nauplius. Among cladoceran species, Bosmina longirostris was dominant. In summer, during the rainy season, zooplankton were flushed out by an associated dam. After the rainy season, rotifera increased rapidly when the water column of the lake was stable. During the fall, zooplankton abundance gradually reduced in accordance with decreasing water temperature. However, the occupation rate of copepod (Copepodid, Nauplius) increased relatively. Zooplankton dynamics were influenced by meteorological changes and hydraulic-hydrological factors, because Lake Paldang is a completely closed ecosystem.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.400-408
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• 2010

The growth and microcystins production characteristics of three species of Microcystis (M. aeruginosa, M. ichthyoblabe, M. viridis) isolated from Yeongchun dam and Ankei dam in Kyungpook Province, South Korea were investigated at temperatures of $15{\sim}35^{\circ}C$ and light intensities of $35{\sim}180\;{\mu}mol\;m^{-2}\;s^{-1}$. All of the three species exhibited the highest growth rates (${\mu}_{max}$) over the $30^{\circ}C$. The maximum growth rates of M. aeruginosa and M. ichthyoblabe was observed at $70\;{\mu}mol\;m^{-2}\;s^{-1}$, while M. viridis showed maximum growth rate at $35\;{\mu}mol\;m^{-2}\;s^{-1}$. The maximum production of total microcystins was observed at $20^{\circ}C$, and the production of microcystins decreased according as temperature increase. The highest microcystins production of M. aeruginosa, M. ichthyoblabe and M. viridis observed at light intensities of $120\;{\mu}mol\;m^{-2}\;s^{-1}$, $70\;{\mu}mol\;m^{-2}\;s^{-1}$ and $35\;{\mu}mol\;m^{-2}\;s^{-1}$, respectively. The concentration of microcyst in production and microcystin types of three species according to temperatures and light intensities showed clear difference between the species.