• Journal of Korea Water Resources Association
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• v.35 no.6
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• pp.807-816
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• 2002

The purpose of the present study was to evaluate the changes of flow duration characteristics of a large river basin due to construction of a dam. The changes of water surface are quantified from remote sensing film taken before and after dam construction. Gongiu gauging station was selected to analyze the changes of flow duration, and annual exceedance series of Gongju and Kyuam gauging station were selected to estimate the changes of flood quantile before and after dam construction. From the analysing results, it was found that the construction of dam contributes to make new duration stable and to decrease flood flow. In conclusion, it was confirmed that the construction of the dam is useful for water supply and flood prevention.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.693-703
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• 2012

Load Duration Curve(LDC) is a useful tool for analyzing water quality characteristics under various stream flow conditions. This study investigated the methods to identify impaired waterbodies in the assessment of water quality goal attainment by using LDC for the management of Total Maximum Daily Loads (TMDLs). Three methods were proposed. Non-typical regime exclusion method is a method to exclude water quality observations in the non-typical extreme flow conditions in order to minimize the influence of non-ordinary water quality. Flow regime weighted average method is a method to calculate weighted mean water quality instead of arithmetic mean in order to consider water characteristics properly on stream flow regime in addition to the effect of Non-typical regime exclusion method. Load exceeded interval comparison method is a method to compare the intervals between the attained and non-attained load duration periods on the LDC. The assessment of water quality goal attainment can be performed more reasonably and precisely considering water quality variations on stream flow conditions by applying these proposed methods.

• Journal of environmental and Sanitary engineering
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• v.17 no.4
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• pp.1-9
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• 2002

In order to define about concern with discharge and water-quality, it is calculated drought flow, low flow, normal flow and wet flow in Chungju watershed from flow duration analysis. Water quality modeling study is performed for forecasting at upstream of Chungju lake. It is devided method of modeling into before and after the equipment of environmental treatment institution. And it is estimated the change of water quality. Before the equipment of environmental treatment, BOD concentration is increased from 23000 to 2006 years at all site and decrease on 2012 years. The rate of increasing BOD concentration is showed height between 2000 years and 2003 years most of all site. And after the equipment of environmental treatment, it is showed first grade of BOD water quality in most of sample site beside Jucheon river. The result of water quality modeling using drought flow showed that a lot of pollution occurred. And water quality using wet flow is good, so much discharge make more improve water quality than little discharge.

• Journal of Environmental Science International
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• v.21 no.1
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• pp.31-39
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• 2012

The objective of this study is to provide pollutant loads delivery ratio for flow duration in Oenam-cheon watershed, which is upstream watershed of Juam Lake. To calculate the delivery ratio by flow duration, rating curves and discharge-loads curves using measured data were established, then Flow Duration Curve(FDC) and pollutant loads delivery ratio curves were constructed. The results show that the delivery ratios for $BOD_5$ for abundant flow($Q_{95}$), ordinary flow($Q_{185}$), low flow($Q_{275}$), and drought flow($Q_{355}$) were 23.9, 12.7, 7.1, and 2.9%, respectively. The delivery ratios of same flow regime for T-N were 58.4, 31.2, 17.2 and 7.1%, respectively. While, the delivery ratios T-P were 17.3, 7.5, 3.4, and 1.1% respectively. In general, delivery ratio of high flow condition showed higher value due to the influence of nonpoint source pollution. Based on the study results, generalized equations were developed for delivery ratio and discharge per unit area, which could be used for ungaged watershed with similar pollution sources.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.751-757
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• 2011

The monitoring technique based on electrical conductivity (EC) can provide researchers with some advantages in maintenance management and is cost-effective as compared with existing CSOs monitoring. In this study, the flow rate estimation using EC data was executed in two sites where storm overflow chamber had installed. In the result of A-site, R2 of second order multinomial between dilution ratio of EC and observed flow rate was showed the range of 0.68 ~ 0.77. And $R^{2}$ of B-site was 0.62 ~ 0.81. On the other hand, cumulative frequency of A-site was 43.4 ~ 52.2% in the relative error level of under 20%. And B-site was 10.1 ~ 46.5%. The flow rate estimation formula was improved through consideration of some parameters including antecedent dry days and rainfall duration. And difference between estimated flow rate and observed flow rate in total rainfall event was very small.

• Korean Institute of Interior Design Journal
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• v.19 no.1
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• pp.85-93
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• 2010

This study aimed to show the possibility of approaching Steven Holl's Stretto House as a vital space identical to the flow of our consciousness through Bergson's philosophy of life by understanding the expression of Bergsonian duration in the house. For the Purpose of this study, Bergson's concept of aesthetic duration was considered and duration in the Stretto House design process was analyzed, Based on the study's findings, duration according to Bergson's expression of reality in the Stretto House was further analyzed. The results of the analysis of duration in the Stretto House design process showed that duration is expressed as phenomenological time through the continuity and movement of the perceptual phenomena of space, sound, light and material that reflected Merleau-Ponty's anchoring and Bartok's Music for Strings, Percussion and Celesta. The results of the analysis of duration as an expression of reality in the Stretto House showed that duration is expressed as real time, as reality's continuous and diverse movement of vital duration, through the image and rhythm based on the intuitive recollection of the real self, sound, light and pond. Consequently, it was shown that the Stretto House could be understood as a vital space in which a vital movement of duration identical with the flow of our consciousness is expressed through the expression of reality in Bergson's philosophy of life. This study is meaningful as a foundational study of the experiential space of phenomena through Bergson's philosophy of life.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.81-85
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• 2006

The output performance characteristics for surveyed sites were analyzed, using developed model. It consists of two main parts, the deciding flow duration characteristic of river and performance prediction model to estimate the output characteristics of small hydropower plants. As a result, It was found that the flowrate concerning with 25% of time ratio on flow duration curve can be selected to design flowrate of small hydropower plants, and the output characteristics of small hydropower plants having overflow dam are different from large scale hydropower plants.

• Clinical and Experimental Reproductive Medicine
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• v.10 no.1
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• pp.1-6
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• 1983

Women were used as their own controls in the comparison of presterilization and poststerilization menstrual patterns. Five parameters were studied: regularity of cycle length, duration and amount of flow and incidence of dysmenorrhea and intermenstrual bleeding. Three parameters in the electrocoagulation group (regularity of cycle length and duration and amount of flow) and one parameter in the tubal ring group (duration of flow) showed significant changes after sterilization. However, by controlling for the effect of previous contraceptive methods used, no significant menstrual pattern changes following sterilization were discerned in either technique group.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.580-588
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• 2009

In this study daily flow rates and delivered pollutant loads of Nakdong river basin are simulated with modified TANK model and minimum variance unbiased estimator. Based on the simulation results, flow duration curves, load duration curves, and delivery ratio duration curves have been established. Then GIS analysis is performed to obtain several hydrological geomorphic characteristics such as watershed area, stream length, watershed slope and runoff curve number. Finally, multiple regression analysis is carried out to estimate empirical equations for pollutants delivery ratio. The results show that there is positive relation between the flow rates and delivery ratios, and the proposed empirical formulas for delivery ratio can predict well river pollutant loads.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.491-494
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• 2006

The output performance characteristics for surveyed sites were analyzed, using developed model. It consists of two main parts, the deciding flow duration characteristic of river and performance prediction model to estimate the output characteristics of small hydropower plants. As a result, it was found that the flowrate concerning with 25% of time ratio on flow duration curve can be selected to design flowrate of small hydropower plants, and the output characteristics of small hydropower plants having overflow dam are different from large scale hydropower plants.