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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
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Journal DOI :
Korean Society of Civil Engeneers
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Volume & Issues
Volume 31, Issue 6D - Dec 2011
Volume 31, Issue 6C - Dec 2011
Volume 31, Issue 6B - Dec 2011
Volume 31, Issue 6A - Dec 2011
Volume 31, Issue 5D - Oct 2011
Volume 31, Issue 5C - Oct 2011
Volume 31, Issue 5B - Oct 2011
Volume 31, Issue 5A - Oct 2011
Volume 31, Issue 4D - Aug 2011
Volume 31, Issue 4C - Aug 2011
Volume 31, Issue 4B - Aug 2011
Volume 31, Issue 4A - Aug 2011
Volume 31, Issue 3D - Jun 2011
Volume 31, Issue 3C - Jun 2011
Volume 31, Issue 3B - Jun 2011
Volume 31, Issue 3A - Jun 2011
Volume 31, Issue 2D - Apr 2011
Volume 31, Issue 2C - Apr 2011
Volume 31, Issue 2B - Apr 2011
Volume 31, Issue 2A - Apr 2011
Volume 31, Issue 1D - Feb 2011
Volume 31, Issue 1C - Feb 2011
Volume 31, Issue 1B - Feb 2011
Volume 31, Issue 1A - Feb 2011
Selecting the target year
Decision of G/R Ratio for the Correction of Mean-Field Bias of Radar Rainfall and Linear Regression Problem
Yoo, Chulsang ; Park, Cheolsoon ; Yoon, Jungsoo ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 393~403
This study theoretically reviewed the empirical G/R ratio by considering three regression and trend lines; the general linear regression curve, linear regression curve passing the origin, and the line passing the origin and the mass center of observed data. This review included the problem of choosing the independent variable and that of considering the zero measurements. This review result was also applied to the Typhoon Maemi in 2003 for their evaluation. Additionally, those regression and trend lines were compared using the RMSE between the corrected radar rainfall and observed rain gauge rainfall to select the most appropriate G/R ratio. Summarizing the results is as follows. First, the results of selecting the rain gauge rainfall as the independent variable were found better than the opposite case. Second, the effect of zero measurements varies depending on the structure of radar and rain gauge rainfall. Finally, the results from the comparison of three regression and trend lines shows that the slope of the regression line passing the origin with its independent variable of rain gauge rainfall would be used most appropriately for the G/R ratio, especially when the corrected radar rainfall is used for the flood analysis. The effect of zero measurements in this case was found not so significant.
The Application of Adaptive Network-based Fuzzy Inference System (ANFIS) for Modeling the Hourly Runoff in the Gapcheon Watershed
Kim, Ho Jun ; Chung, Gunhui ; Lee, Do-Hun ; Lee, Eun Tae ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 405~414
The adaptive network-based fuzzy inference system (ANFIS) which had a success for time series prediction and system control was applied for modeling the hourly runoff in the Gapcheon watershed. The ANFIS used the antecedent rainfall and runoff as the input. The ANFIS was trained by varying the various simulation factors such as mean areal rainfall estimation, the number of input variables, the type of membership function and the number of membership function. The root mean square error (RMSE), mean peak runoff error (PE), and mean peak time error (TE) were used for validating the ANFIS simulation. The ANFIS predicted runoff was in good agreement with the measured runoff and the applicability of ANFIS for modelling the hourly runoff appeared to be good. The forecasting ability of ANFIS up to the maximum 8 lead hour was investigated by applying the different input structure to ANFIS model. The accuracy of ANFIS for predicting the hourly runoff was reduced as the forecasting lead hours increased. The long-term predictability of ANFIS for forecasting the hourly runoff at longer lead hours appeared to be limited. The ANFIS might be useful for modeling the hourly runoff and has an advantage over the physically based models because the model construction of ANFIS based on only input and output data is relatively simple.
Development of Flood Control Effect Index by Using Fuzzy Set Theory
Kim, Juuk ; Choi, Changwon ; Yi, Jaeeung ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 415~429
Quantitative evaluation indexes for flood control effect of a multi-purpose reservoir used widely in Korea are the discharge control rate, reservoir release rate, reservoir storage rate, and flood control storage utilization rate. Because these indexes usually use and compare inflow, release, and storage data directly, the uncertainties included in these data are not considered in evaluation process, and the downstream flood control effects are not assessed properly. Also, since the acceptable partial failure in a design of water resources system is not considered, the development of a new flood control effect evaluation index is required. Fuzzy set theory is therefore applied to the development of the index in order to consider the data uncertainty, the downstream flood control effect, and the acceptable partial failure. In this study, the flood control effect of a multi-purpose reservoir is evaluated using the flood control effect index developed by applying fuzzy set theory. The Chungju reservoir basin was selected as a study basin and the storm events of July, 2006 are used to study the applicability of the developed index. The related factors for flood control effect are fuzzified, the acceptable failure region is divided from the system state to evaluate the flood control effect using developed flood control effect index. The flood control effect index were calculated by applying to the study basin and storm events. The results show that the developed index can represent the flood control effect of a reservoir more realistically and objectively than the existing index.
Regression Analysis of the Log-Normally Distributed Data and Mean Field Bias Correction of Radar Rainfall
Yoo, Chul Sang ; Park, Cheol Soon ; Yoon, Jung Soo ; Ha, Eun Ho ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 431~438
This study investigated the problem of mean-field bias correction under the assumption that the radar and rain gauge rainfall data follow the log-normal distribution. Regression curves for the average, median and mode of the radar and rain gauge rainfall were derived and evaluated for their usefulness. Additionally, these regression curves were compared with those derived under the assumption that the radar and rain gauge data follow the normal distribution. This study investigated the regression results for the Typhoon Meami occurred in 2003 as an example. As results, three regression lines with the radar rainfall as the independent variable were found to underestimate the rainfall, while those with the rain gauge rainfall as the independent variable to overestimate. Among three types of regression curves considered, the result for the average was most appropriate. However this case was found to be inferior to the regression line passing the origin under the assumption of the normal distribution with the rain gauge rainfall as its independent variable. So it was hard to conclude that the consideration of the log-normality on the correction of radar rainfall is beneficial.
Adaptation Capability of Reservoirs Considering Climate Change in the Han River Basin, South Korea
Chung, Gunhui ; Jeon, Myeonho ; Kim, Hungsoo ; Kim, Tae-Woong ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 439~447
It is a main concern for sustainable development in water resources management to evaluate adaptation capability of water resources structures under the future climate conditions. This study introduced the Fuzzy Inference System (FIS) to represent the change of release and storage of reservoirs in the Han River basin corresponding to various inflows. Defining the adaptation capability of reservoirs as the change of maximum and/or minimum of storage corresponding to the change of inflow, the study showed that Gangdong Dam has the worst adaptation capability on the variation of inflow, while Soyanggang Dam has the best capability. This study also constructed an Adaptive Neuro-Fuzzy Inference System (ANFIS) for the more accurate and efficient simulation of the adaptation capability of the Soyanggang Dam. Nine Inflow scenarios were generated using historical data from frequency analysis and synthetic data from two general circulation models with different climate change scenarios. The ANFIS showed significantly different consequences of the release and reservoir storage upon inflow scenarios of Soyanggang Dam, whilst it provides stable reservoir operations despite the variability of rainfall pattern.
Non-stationary Rainfall Frequency Analysis Based on Residual Analysis
Jang, Sun-Woo ; Seo, Lynn ; Kim, Tae-Woong ; Ahn, Jae-Hyun ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 449~457
Recently, increasing heavy rainfalls due to climate change and/or variability result in hydro-climatic disasters being accelerated. To cope with the extreme rainfall events in the future, hydrologic frequency analysis is usually used to estimate design rainfalls in a design target year. The rainfall data series applied to the hydrologic frequency analysis is assumed to be stationary. However, recent observations indicate that the data series might not preserve the statistical properties of rainfall in the future. This study incorporated the residual analysis and the hydrologic frequency analysis to estimate design rainfalls in a design target year considering the non-stationarity of rainfall. The residual time series were generated using a linear regression line constructed from the observations. After finding the proper probability density function for the residuals, considering the increasing or decreasing trend, rainfalls quantiles were estimated corresponding to specific design return periods in a design target year. The results from applying the method to 14 gauging stations indicate that the proposed method provides appropriate design rainfalls and reduces the prediction errors compared with the conventional rainfall frequency analysis which assumes that the rainfall data are stationary.
Research on the Resources Investigations of Small Hydropower Generation in Northern Gyeong-Buk Area
Kim, Jung-Hun ; Kim, Dong-Hyun ; Hwang, Jong-Kyu ; Kim, Sungwon ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 459~466
In this study, the resources investigations of small hydropower generation were carried out for the five proposed sites in northern Gyeong-buk area. They consisted of the discharge measurements, rating-curve, flow duration curves, electricity generation, and economic analysis, respectively. The basic data were suggested to select the optimal small hydropower sites in northern Gyeong-buk area. The sites for Yecheon Gun and Munsu Myeon as a result are the best proposed ones using economic analysis. We considered, however, that the finacial benefit for small hydropower development may be small under 500 kW facility. The optimal proposed site over 500 kW facility was suggested as Yeongyang Gun in this study.
Experimental Investigation of Effects of Sediment Concentration and Bed Slope on Debris Flow Deposition in Culvert
Kim, Youngil ; Paik, Joongcheol ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 467~474
Debris flow is one of the most hazardous natural processes in mountainous regions. The degradation of discharge capacity of drainage facilities due to debris flows may result in damages of properties and casualty as well as road. Understanding and accurate reproducing flow behaviour of debris flows at various conditions, such as sediment volume concentration and approaching channel and culvert slopes, are prerequisite to develop advanced design criteria for drainage facilities to prevent such damages. We carried out a series of laboratory experiments of debris flows in a rectangular channel of constant width with an abrupt change of bottom slope. The experimental flume consists of an approaching channel part with the bed slope ranging
and the test channel with slope ranging from
which mimics a typical drainage culvert. The experiments have been conducted for 22 test cases with various flow conditions of channel slopes and sediment volume concentration of debris flows to investigate those effects on the behaviour of debris flows. The results show that, according to sediment volume concentration, the depth of debris flow is approximately 50% to 150% larger than that of fresh water flow at the same flow rate. Experimental results quantitatively present that flow behaviour and deposit history of debris flows in the culvert depend on the slopes of the approaching and drainage channels and sediment volume concentration. Based on the experimental results, furthermore, a logistic model is developed to find the optimized culvert slope which prevents the debris flow from depositing in the culvert.
TMDL Evaluation of Nakdong River Basin Using Load Duration Curve and Streamflow-Load Rating Curve
Shon, Tae Seok ; Joo, Jae Seung ; Park, Jae Beom ; Shin, Hyun Suk ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 475~481
The TMDL standard flow as applying watershed management regime uses the average low flow of past 10 years. Moreover, the TMDL implementation assessment has been enforced through management of pollutant load satisfied objective water quality. Even though the present allocation and management through averaged low flow are still convenient, they are not enough to solve ultimate goals of watershed management to keep up recovery of water body. To maintain the same water quality concentration, the standard flow is required to consider total discharge in management plan which helps to keep healthy ecosystem. In view of this, it would be possible to approach reasonable assessment by reflecting variably changeable discharge from precipitation-streamflow relation and the TMDL standard establishment considering artificial regulated flow. Therefore, this study attempts to develop the TMDL method using Load Duration Curve (LDC) and Streamflow-Load Rating Curve (QLRC) considering total discharge and finds drawbacks with solutions as applying on Nakdong river TMDL unit watershed. Finally, this research evaluates possibility of application on pollutant load allocating and implementation assessment in Korea.
Development of Numerical Model for Scour Analysis under Wave Loads in Front of an Impermeable Submerged Breakwater
Hur, Dong-Soo ; Jeon, Ho-Seong ;
Journal of The Korean Society of Civil Engineers, volume 31, issue 5B, 2011, Pages 483~489
In this study, the coupled-numerical model has been newly developed to investigate numerically scouring and deposition around a coastal structure like a submerged breakwater using a numerical wave model and a lagrangian particle model for sand transport. As a numerical wave model, LES-WASS-2D (Hur and Choi, 2008) is adopted. The model is able to consider the flow through a porous midium with inertial, laminar and turbulent resistance term and determine the eddy viscosity with LES turbulence model. Distinct element method (Cundall and Strack, 1979), which is able to apply to many dynamical analysis of particulate media, as a lagrangian particle model for sand transport is newly coupled to the numerical wave model. The numerical simulation has been carried out to examine the scour problem in front of an impermeable submerged breakwater using the newly coupled-numerical model. The numerical results has been compared qualitatively with an existing experimental data and then its applicability has been discussed.