• 생태와환경
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• 제44권2호
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• pp.113-128
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• 2011

본 연구는 2007년 10월부터 2008년 7월까지 대청호의 중요 유입지천인 소옥천에 대해 이화학적 수질, 식물플랑크톤 군집을 분석하고 수질영양단계를 평가하였다. 식물플랑크톤은 Microcystis aeruginosa와 Aulacoseira granulata 등 수화원인종의 출현빈도가 높아 잠재적으로 남조류 및 규조류에 의한 녹조현상이 연중 지속될 수 있을 것으로 판단된다. 또한 Oscillatoria limasa를 포함한 10분류군의 오염수역 지표종이 출현하였다. TSI (Trophic Status Index)와 LTSI (Lake Trophic Status Index)에 의한 수질영양단계 평가 결과, TSI는 중부영양~부영양화단계, LTSI는 중부영양단계~과영양단계로 평가되었다.

• Wind and Structures
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• 제7권5호
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• pp.293-304
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• 2004

The Dongting Lake Bridge is a cable-stayed bridge crossing the Dongting Lake where it meets the Yangtze River in southern central China. Several intensive wind-rain induced vibrations had been observed since its open to traffic in 1999. To investigate the possibility of using MR damping systems to reduce cable vibration, a series of field tests were conducted. Based on the promising research results, MR damping system was installed on the longest 156 stay cables of Dongting Lake Bridge in June 2002, making it the worlds first application of MR dampers on cable-stayed bridge to suppress the wind-rain induced cable vibration. As a visible and permanent aspect of the bridge, the MR damping system must be aesthetically pleasing, reliable, durable, easy to maintain, as well as effective in vibration mitigation. Substantial work was done to meet these requirements. This paper describes field tests and the implementation of MR damping systems for cable vibration reduction. Three-years reliable service of this system proves its durability.

• Ocean and Polar Research
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• 제32권3호
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• pp.187-201
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• 2010

The purpose of this study was to investigate the temporal and spatial variability of taxonomic groups and major species of the mesozooplankton community in Lake Shihwa, Korea. Monthly collections were carried out at five stations in Lake Shihwa for a period of one year. The mesozooplankton community showed distinct seasonal variability with water temperature and salinity. Major mesozooplankton species in each seasonal community were derived from non-metric MDS and SIMPER as follows: winter community (Acartia hongi and Eurytemora pacifica), spring community (Acartia hudsonica and Polychaeta larvae), summer community (Acartia sinjiensis, Pavocalanus crassirostris, Evadne tergestina and Cirripedia nauplii) and fall community (Paracalanus indicus and Podon leuckarti). The succession of the seasonal species, A. hudsonica and A. sinjiensis, was the most remarkable event during the seasonal changes of the mesozooplankton community. The species response curve of these species fitted with the logistic regression in relation to water temperature and salinity. The curve also correctly represented the characteristics of the occurrence of A. hudsonica and A. sinjiensis in Lake Shihwa.

• International Journal of Fluid Machinery and Systems
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• 제5권4호
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• pp.174-179
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• 2012

A numerical study to investigate the effect of intake vortex occurrence on the performance of an axial hydraulic turbine for generating tidal power energy in Sihwa-lake tidal power plant, Korea, is performed. Numerical analysis of the flow through an sxial hydraulic turbine is carried out by solving three-dimensional Reynolds-averaged Navier-Stokes dquations with the shear stress transport turbulence model. In the real turbine operation, the vortex flows are occurred in both the side corners around the intake of an axial hydraulic turbine due to the interaction between the inflow angle of water and intake structure. To analyze these vortex phenomena and to evaluate their impacts on the turbine performance, the internal flow fields of the axial hydraulic turbines with the different inflow angles are compared with their performances. As the results of numerical analysis, the vortex flows do not directly affect the turbine performance.

• 한국유체기계학회 논문집
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• 제13권1호
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• pp.23-28
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• 2010

A draft tube which has impeller to elevate bottom water and spread it over surface of lake water, induces convective circulation of lake water, a Long-Distance Circulation (LDC). Circulation of lake water make stratified water mixed and enhance DO (Dissolved Oxygen) of bottom water. Circulation rate of water is determined by draft rate of the tube, which is dependent on design parameters of the draft tube system, i. e. dimension of impeller and diffuser, inclined angle of impeller, impeller shape, and rotational speed. In this study, change in draft rate and power consumption of circulation equipment was investigated numerically with changing impeller dimension, angle and rotational speed. It was found that flowrate of draft water was increased as the dimensions of draft tube and impeller, and rotational speed and inclined angle of impeller increased. The power consumption was also elevated with increasing parameter values, and final selection of parameter values was made to satisfy target flowrates and power consumption.

• 아시안잔디학회지
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• 제10권4호
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• pp.297-304
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• 1996

The investigation was performed to reveal the removal rate of metal constituents of litters in a Phragmites communis Miseanthus sacchariflorus, Typha angastata and Seirpas tabernaemontani grasslands in the lake Paldangho. The removal rates of metal constituents are determined by the mathematical models. The removal rates and time required to decay up to a percentage of each metal constituent were calculated using these model. The removal rates of Cu, Fe and Zn were 0.61, 0.58 and 0.79 in Phragmites communis 0.39, 0.47 and 0.68 in Miseanthus saccharflorus; 0.26, 0.09 and 0.23 in Typha angustata: 0.56, 0.27 and 0.67 in Seirpus tabernaemontani respectively. The periods required to reach half time to the stedy state of the removal and accumulation for Cu, Fe and Zn were 1,13,1.19 and 0.79 years in Phragmites communis; 1.79, 1.49 and 1.02 years in Miscanthus sacchariflorus; 2.70, 7.43 and 2.96 years in Typha angustata ; 1.23, 2.58 and 1.04 years in Scirqus tabernaemontani, re-spectively. Key words: Phragmites communis, Miscanthus sacchariflorus, Typha angustata and Scirpus tabernaemontani, lake Paldangho, Removal rate, Cupper, Iron, Zinc.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• 제2호
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• pp.130-139
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• 2004

Shiwha Lake is an excellent example of a body of water restored from a state of heavy pollution to a cleaner and more ecological state. This paper will explore techniques and methods available to landscape planning for the creation of new migratory birds habitats in Shiwha Lake. Because Shiwha lake is located adjacent to a new industrial site on reclaimed land, any planning effort aimed at restoring bird habitats must carefully consider the existing context. This plan had 3 goals; (1) to restore the coastal environment, (2) to create a habitat for migratory birds, and (3) to administer environmental education programs. To achieve these goals, several objectives were determined and planning criteria were proposed for topology, water environment(fresh, brackish and salt water swamps), zoning(for experts and general visitors), circulations, planting and mounding. The flora and fauna of the site was surveyed, and 5 alternatives were suggested and compared in several aspects. Planting species were carefully selected considering target birds and habitat requirements. In order to increase bio-diversity of the site, the plan proposed multi-staired mounds and extensive drainage systems. Bird watching facilities with natural materials, and the remote observing system using CCTV and the internet were some of the ecological techniques recommended by the plan. The bird watching trails are divided into two different zones for experts and general visitors.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.211-211
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• 2015

Mekong River is the world's $10^{th}$ longest river and runs through China's Yunnan province, Burma, Thailand, Laos, Cambodia and Vietnam. And Tonle Sap Lake, the largest fresh water body in Southeast Asia and the heart of Mekong River system, covers an area $2,500-3,000Km^2$ in dry season and $10,000-16,000Km^2$ in wet season. As previously noted, the water within Sap river flows from the Mekong River to Tonle Sap Lake in flood season (between June and October) and backward to Mekong River in dry season. Recently the flow regime of Sap River might be significantly affected by the development of large dams in upstream region of Mekong River. This paper aims at basic study about the large scale flood inundation of Cambodia using by CAESAR-Lisflood. CAESAR-Lisflood is a geomorphologic / Landscape evolution model that combines the Lisflood-FP 2d hydrodynamic flow model (Bates et al, 2010) with the CAESAR geomorphic model to simulate flow hydrograph and erosion/deposition in river catchments and reaches over time scales from hours to 1000's of years. This model is based on the simplified full Saint-Venant Equation so that it can simulate the interacted flow of between Mekong River and Tonle Sap Lake especially focusing on the flow direction change of Sap River by season.

• 한국물환경학회지
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• 제27권4호
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• pp.433-437
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• 2011

The study is conducted to evaluate loading of organic matter as seasonal changes during non-storm period into Lake Paldang which is used to a major drinking water source. Samples were taken in Lake Paldang intake during non-storm period and were analyzed loading of organic matter. From the results of the survey, improving of the water quality showed remarkable tendency depending on the changing periods from summer to fall and from fall to winter. Dilution effect from the increase of base run-off caused by the concentrated rainfall in rainy season, the characteristics of Korea's climate seems to have to be the reason. On the other hand, deteriorating of the water quality showed tendency depending on the changing periods from winter to spring and from spring to summer. Increase of Cyanobacteria etc. is explained by seasonal effects which are a small amount of the rainfall in winter and spring and gradational increase of water temperature.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.176-176
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• 2023

The Tonle Sap is the richest and diverseness of freshwater ecosystem in Southeast Asia, receiving nurturing water flows from the Mekong and its immediate basin. In addition, the rapid development in the Tonle Sap Lake (TSL) Basin, and flood inundation may threaten the natural diversities and characteristics. The impacts of flood inundation in 11 sub-basins contributing to the Tonle Sap Lake were assessed using the Rainfall-Runoff-Inundation (RRI) model to quantify the potential magnitude and extent of the flooding. The RRI model is set up by using gauged rainfall data to simulate the information of river discharge and flood inundation of huge possible flood events. Moreover, two satellite precipitation products (SPPs), CHIRPS and GSMaP, within respectively spatial resolutions of 0.05° and 0.1°, are utilized as an input for the RRI model to simulate river discharge, flood depth, and flood extent for the great TSL Basin of Cambodia. This study used statistical indicators such as NSE, PBIAS, RSR, and R2 as crucial indices to evaluate the performance of the RRI model. Therefore, the findings of this study could provide promising guidance in hydrological modeling and the significant implications for flood risk management and disaster preparedness in the region.