• Water for future
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• v.35 no.5
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• pp.51-59
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• 2002

In recent years the human impact on the environment becomes increasing lift threatening, calls for the better management of resources. In field of water quality of river flow, the best way to conserve water quality is specific efforts to control the pollutant loadings and treat the loadings in the basin to reduce the discharge of pollutant loadings to river. But in general the water quality influenced by the dam discharge. Especially in dry season, it is more dominant way to improve the water quality which contaminated with the pollutant loadings from the basin. The dam discharge amounts of the 2 dams in the Keum River that maintain the down stream water quality were estimated for the year of 1999, 2001, 2006, 2011, in case of irrigation and non-irrigation seasons. The pollutant loadings for the basin are estimated with the planning of treatment plants construction schedule for every sub-basins. The river flow rates were considered low flow as 2.33 year low flow and 10 year low flow. The QUAL2E model was used as a tool of simulation.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.2
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• pp.25-39
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• 2019

The water pollution Accident in the South Han River is increasing due to increase of pollutants inflow from small streams from rural areas and reduced flow rate. This study predicted the change of water quality in the main stream of the South Han River due to climate change through the linkage of watershed and water quality models. Also, This study analyzed the effect of water quality improvement on Seomgang and the South Han River by securing the flow during the dry season. According to the scenarios for securing the river flow during drought season, the river flow in the Seomgang is increased up to 2.19 times, and the water quality during the drought season was improved up to $BOD_5$ 20.5%, T-N 40.8%, T-P 53.4%. Also, the water quality of the main stream of the South Han River improved to 5.22% of $BOD_5$, 5.42% of T-N and 7.69% of T-P as the river flow was secured from the Seomgang. The result of this study confirms that securing the baseflow in the Seomgang according to the scenarios for securing the river flow during the dry season has a positive effect on the improvement of the water quality of the rivers in the main river of the Seomgang and South Han River. The results of this study will contribute to the establishment of reasonable management to improve the water quality of the main stream of the Seomgang and South Han River.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.1
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• pp.55-65
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• 2006

The air and water flow distribution are experimentally studied for a round header - flat tube geometry simulating a parallel flow heat exchanger. The number of branch flat tube is thirty. The effects of tube outlet direction, tube protrusion depth as well as mass flux, and quality are investigated. The flow at the header inlet is identified as annular. For the downward flow configuration, the water flow distribution is significantly affected by the tube protrusion depth. For flush-mounted configuration, most of the water flows through frontal part of the header. As the protrusion depth increases, more water is forced to the rear part of the header. The effect of mass flux or quality is qualitatively the same as that of the protrusion depth. Increase of the mass flux or quality forces the water to rear part of the header. For the upward flow configuration, however, most of the water flows through rear part of the header. The protrusion depth, mass flux, or quality does not significantly alter the flow pattern. Possible explanations are provided based on the flow visualization results. Negligible difference on the water flow distribution was observed between the parallel and the reverse flow configuration.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.574-581
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• 2012

It is important to analyze the status of water quality with relation to the stream flow to attain water quality goal more effectively in the unit watersheds for the management of Total Maximum Daily Loads (TMDLs). This study developed a flow duration-water quality distribution graph to figure out water quality appearances on the flow variation and analyzed contributions of water quality observations to the impaired water bodies quantitatively by hydrologic conditions. Factors relating to water quality variation can be analyzed more precisely and assessed on the base of quantified contributions. It is considered that this approach could be utilized to establish a more effective plan for the water quality improvement including the prioritization of pollution reduction options.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.879-882
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• 2004

Two-phase flow exists in many industrial components. Characteristics of two-phase flow have been studied by many researchers; however, a further study of the two-phase is required for flow-induced vibration. Characteristics of two-phase flow were measured by force sensor at the end of a vertical pipe. The predominant frequency of fluctuation was obtained for various speeds of flow pattern. A correlation to slug frequency for horizontal flow was obtained by Heywood & Richardson (1979), while Legius et al (1997) for vertical flow. A coefficient based on the correlation is estimated and then compared to the existing ones. The existing empirical formulations for average void fraction were proposed by Wallis (1969), Zuber et al (1967) and Ishii (1970). In the present result, flow parameters, such as flow quality and real velocity, are evaluated with void fraction.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.125-135
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• 2009

Reliable long-term flows by SWAT-K model were applied to the relationship between stream flow and pollutant load derived from 8-day measured data of Ministry of Environment (MOE) in order to obtain continuous loadograph and evaluate accuracy in water quality modeling for the Chungju dam watershed. The measured flow were compared with flow duration curve from the model, and it showed that measured values corresponded to the almost full range of stream flow conditions except at Odae A. And there was significant relationship ($R^2=0.60{\sim}0.97$) between measured flow and water quality load at all unit-watersheds. Applying this relationship to simulated flows, continuous loadograph was obtained and compared with modeled pollutant loads. Although there were some differences during some dry and flood seasons, those were not significant and overall trend showed a good agreement. From the results, we would be able to derive a continuous loadograph based on measured data at total maximum daily loads (TMDLs) unit-watersheds on a national scale, in which stream flow and water quality have been measured at 8-day intervals since 2004, and this could be helpful to utilize distributed water quality models with difficulty in calibrating and validating parameters from lack of measured data at present.

• Journal of Environmental Health Sciences
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• v.38 no.5
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• pp.438-447
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• 2012

Objective: The objective of this study was to suggest a method through which load duration curve was used to assess the achievement of water quality targets in accordance with the criteria for pollutant load depending on flow rate variation. Methods: The stage-discharge curve and flow duration curve of Jungnang Stream were deduced. Using water quality targets and measurement of the stream, the flow duration curve was also drawn. Based on these, the feasibility of achievement of water quality targets in respect to flow rate was assessed. Results: In terms of the load duration curve of the stream, it was observed that excess of criteria for concentrations of $BOD_5$, $COD_{Mn}$ and SS frequently occurred. On the other hand, when the flow rate was low, the concentrations of T-N and T-P exceeded the criteria. Conclusions: Through the load duration curve, the overall water quality of Jungnang Stream was understood. When the flow rate is high, management of point source of $BOD_5$, $COD_{Mn}$ and SS is needed to achieve water quality targets for Jungnang Stream. On the other hand, when the flow rate is low, the management of non-point source T-N and T-P is necessary to attain the water quality goal.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.417-425
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• 2018

The purpose of this study was to analyzed the correlation between upper extremity function, activities of daily living, quality of life and therapeutic flow in stroke clients and identify the factors influencing therapeutic flow. Total 249 stroke patients from 13 hospitals were measure at therapist and researcher for upper extremity function, activities of daily living, therapeutic flow and quality of life. Factors that affect the quality of life correlation as s result of positively correlated with upper extremity function(r=.312, p<.001), activities of daily living(r=.605, p<.001), therapeutic flow(r=.525, p<.001). And the effect on quality of life in stroke clients variables affecting therapeutic flow(${\beta}=.344$, p<.001), activities of daily living(${\beta}=.293$, p<.05) and Time since of onset(${\beta}=.145$, p<.05) were the order of analysis. The regression model explained 35.9% of variances(F=35.736, p<.001). Therefore, it was found that therapeutic flow in stroke clients is an important factor for quality of life, future therapeutic flow study will continue to be needed.

• Journal of Environmental Impact Assessment
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• v.8 no.3
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• pp.13-22
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• 1999

Tidal flow and water quality were simulated in this paper to assess environmental impact caused by pier construction projects in Onsan harbor system. The Surfacewater Modeling System (SMS) was applied to the Onsan harbor system, where coastal reclamation and dredging were planned to build the piers. A finite element mesh was constructed and refined to cover the complicated geometry of the Onsan harbor and the proposed reclamation area. The time variable change of tidal height at harbor inlet was given as an input condition to tidal simulation. The water quality simulation was based on the discharge rate of suspended solids at the reclamation area. The simulation results have shown reasonable agreements with real situations in both tidal flow and water quality. According to the proposed plan, tidal flow and water quality were predicted during and after the pier construction. The tidal simulation study showed that there would be no discernible change of tidal current in the harbor except for the dredged area. The water quality simulation, however, predicted that suspended solids would increase significantly near the reclaimed and dredged areas during construction.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1045-1051
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• 2006

Geumgang canal is planned to connect Geumgang lake with Saemangeum lake to accelerate desalinization and dilute polluted water to improve water quality in Saemangeum lake. The purpose of this study is to evaluate the impact of water quality on Geumgang lake by diversion of its lake flow to Saemangeum lake. WASP5 model was used to estimate water quality of Geumgang lake. Model calibration and verification were done for water quality data for 2001 and 2002. Water quality concentrations in Geumgang lake were simulated for 4 scenarios, which were considered whether the Geumgang canal is built or not. As a result of simulations, there was little impact on water quality in Geumgang lake, though a little of the Geumgang lake flow diverted to Saemangeum lake. As the Geumgang canal is planned to divert the Geumgang water flow which were discharged into the sea through sluice gates when canal is not built, it is thought that there will be little change by diversion of water flow.