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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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Korean Society of Civil Engeneers
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Volume & Issues
Volume 29, Issue 6D - Nov 2009
Volume 29, Issue 6C - Nov 2009
Volume 29, Issue 6B - Nov 2009
Volume 29, Issue 6A - Nov 2009
Volume 29, Issue 5D - Sep 2009
Volume 29, Issue 5C - Sep 2009
Volume 29, Issue 5B - Sep 2009
Volume 29, Issue 5A - Sep 2009
Volume 29, Issue 4D - Jul 2009
Volume 29, Issue 4B - Jul 2009
Volume 29, Issue 4A - Jul 2009
Volume 29, Issue 4C - May 2009
Volume 29, Issue 3D - May 2009
Volume 29, Issue 3C - May 2009
Volume 29, Issue 3B - May 2009
Volume 29, Issue 3A - May 2009
Volume 29, Issue 2D - Mar 2009
Volume 29, Issue 2C - Mar 2009
Volume 29, Issue 2B - Mar 2009
Volume 29, Issue 2A - Mar 2009
Volume 29, Issue 1D - Jan 2009
Volume 29, Issue 1C - Jan 2009
Volume 29, Issue 1B - Jan 2009
Volume 29, Issue 1A - Jan 2009
Selecting the target year
Development of a Stochastic Precipitation Generation Model for Generating Multi-site Daily Precipitation
Jeong, Dae-Il ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 397~408
In this study, a stochastic precipitation generation framework for simultaneous simulation of daily precipitation at multiple sites is presented. The precipitation occurrence at individual sites is generated using hybrid-order Markov chain model which allows higher-order dependence for dry sequences. The precipitation amounts are reproduced using Anscombe residuals and gamma distributions. Multisite spatial correlations in the precipitation occurrence and amount series are represented with spatially correlated random numbers. The proposed model is applied for a network of 17 locations in the middle of Korean peninsular. Evaluation statistics are reported by generating 50 realizations of the precipitation of length equal to the observed record. The analysis of results show that the model reproduces wet day number, wet and dry day spell, and mean and standard deviation of wet day amount fairly well. However, mean values of 50 realizations of generated precipitation series yield around 23% Root Mean Square Errors (RMSE) of the average value of observed maximum numbers of consecutive wet and dry days and 17% RMSE of the average value of observed annual maximum precipitations for return periods of 100 and 200 years. The provided model also reproduces spatial correlations in observed precipitation occurrence and amount series accurately.
Synoptic Change Characteristics of the East Asia Climate Appeared in Seoul Rainfall and Climatic Index Data
Hwang, Seok Hwan ; Kim, Joong Hoon ; Yoo, Chulsang ; Chung, Gunhui ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 409~417
In this study it was assessed the accuracy of the Chukwooki rainfall data in Seoul by comparing with tree-ring width index data, sunspot numbers, southern oscillation index (SOI) and global temperature anomaly. And it was investigated the correlations of climatic change and change characteristics in past north-east asia by comparisons of tree-ring width index data in near Korea. The results of this study shows that Chukwooki rainfall data has the strong reliance since the trends and depths of change are very well matched with other comparative data. And with the results by compared with tree-ring width index data in six sites of near Korea, climates of north-east asia are changed with strong correlations as being temporal and spatial and longterm periodic possibility of reproducing are exist on those changes. However characteristics of climate change post 1960 A.D. are investigated as represented differently to past although statistical moving characteristics or changing criterion are within the limitations of reproducing phase in the past since they represent the different trends and irregularity and their frequencies are increase. The results of this study are widely used on long-term forecasting for climate change in north-east asia.
Estimation of Raw Water Quality Improvement Benefit of Water Service Using WTP
Yeo, Kyul Dong ; Yi, Choong Sung ; Lee, Sang Won ; Shim, Myung Pil ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 419~427
In existing studies about benefit of water quality improvement using WTP, the object of survey is described pre-policy water quality as "current water quality" and improved (post-policy) water quality as "boatable, fishable and swimmable". Multiply WTP by the number of households of basin is total benefit. The existing studies are not benefit of a specific water resource business but benefit of a policy on unsubstantial water resource business. Because of a lack of objectivity and oversimplification, it is difficult for survey respondents to understand an object of survey. The purpose of this study is to evaluate a benefit estimation methodology for raw water quality improvement in water resource development business. After conducting a survey of WTP of 1,000 housewives who is using water service in the National Capital region, the relational expression of water quality improvement (BOD) and WTP is derived by using statistical analysis of the survey. As a case study, the stream water quality improvement benefit of Song Li Won multipurpose dam was evaluated, which is planned to be built at the local secondary stream section on Nae Sung stream in Nak-Dong River system. As a result of study, annual average benefit evaluation is 5,980 million won on the average annual planned discharge, 8,663 million won on the planned discharge during the period except for wet season (July to October), 11,905 million won on the planned discharge during water quality declining period and 14,502 million won on the planned discharge during water quality declining period respectively. By using the relational expression of BOD-WTP, it is easy to estimate the benefit without regard for water quality.
Propagation Analysis of Dam Break Wave using Approximate Riemann solver
Kim, Byung Hyun ; Han, Kun Yeon ; Ahn, Ki Hong ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 429~439
When Catastrophic extreme flood occurs due to dam break, the response time for flood warning is much shorter than for natural floods. Numerical models can be powerful tools to predict behaviors in flood wave propagation and to provide the information about the flooded area, wave front arrival time and water depth and so on. But flood wave propagation due to dam break can be a process of difficult mathematical characterization since the flood wave includes discontinuous flow and dry bed propagation. Nevertheless, a lot of numerical models using finite volume method have been recently developed to simulate flood inundation due to dam break. As Finite volume methods are based on the integral form of the conservation equations, finite volume model can easily capture discontinuous flows and shock wave. In this study the numerical model using Riemann approximate solvers and finite volume method applied to the conservative form for two-dimensional shallow water equation was developed. The MUSCL scheme with surface gradient method for reconstruction of conservation variables in continuity and momentum equations is used in the predictor-corrector procedure and the scheme is second order accurate both in space and time. The developed finite volume model is applied to 2D partial dam break flows and dam break flows with triangular bump and validated by comparing numerical solution with laboratory measurements data and other researcher's data.
Downscaling Technique of Monthly GCM Using Daily Precipitation Generator
Kyoung, Min Soo ; Lee, Jung Ki ; Kim, Hung Soo ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 441~452
This paper describes the evaluation technique for climate change effect on daily precipitation frequency using daily precipitation generator that can use outputs of the climate model offered by IPCC DDC. Seoul station of KMA was selected as a study site. This study developed daily precipitation generation model based on two-state markov chain model which have transition probability, scale parameter, and shape parameter of Gamma-2 distribution. Each parameters were estimated from regression analysis between mentioned parameters and monthly total precipitation. Then the regression equations were applied for computing 4 parameters equal to monthly total precipitation downscaled by K-NN to generate daily precipitation considering climate change. A2 scenario of the BCM2 model was projected based on 20c3m(20th Century climate) scenario and difference of daily rainfall frequency was added to the observed rainfall frequency. Gumbel distribution function was used as a probability density function and parameters were estimated using probability weighted moments method for frequency analysis. As a result, there is a small decrease in 2020s and rainfall frequencies of 2050s, 2080s are little bit increased.
Analysis of Flood Stage in a Confluence using the Dynamic Numerical Model
Kim, Ji Sung ; Kim, Keuk Soo ; Kim, Won ; Kim, Sang Ho ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 453~461
In this study, a dynamic numerical model, FLDWAV, is used for analyzing the backwater effect of flood stage in YeongWeol station, which is located on the confluence upstream where Pyeongchang river joins Han river. Given various inflow discharges of both main stream and tributary, the feasible stage-discharge relationships at the YeongWeol station and the upstream range of the backwater effect were computed. The results show that the relationships are completely different according to each of the inflow discharges from tributary and the maximum difference of stage is about 4.0 m. Therefore, the development of a single relationship of stage and discharge is very difficult problem in the zone of backwater effect. The increase of stage in the junction due to the lateral inflow has an effect on upstream stage up to about 8.0 km. The well-calibrated and verified dynamic wave routing model will be a useful tool for the flood forecast in the zone of backwater effect rather than conventional hydrological routing model.
Effect of Beach Curvature on Wave Fields in Coastal Area with Submerged Breakwaters
Hur, Dong-Soo ; Lee, Woo-Dong ; Yeom, Gyeong-Seon ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 463~472
The aim of this study is to examine the effect of beach curvature on wave fields in coastal area with Submerged Breakwaters using the 3D numerical model that is able to simulate directly interaction of WAve Structure Sandy beach (LES-WASS-3D). At first, the adopted model was validated through the comparison with an existing experimental data and showed fairly nice agreement. And then, the numerical simulations have been performed to investigate the effect of according to the variation of beach curvature. Based on the numerical results, the wave height, mean surface elevation, mean flow around submerged breakwaters and longshore distributions of run-up height have been discussed in relation to the variation of beach curvature.
Numerical Analysis of Wave Transformation of Bore in 2-Dimensional Water Channel and Resultant Wave Loads Acting on 2-Dimensional Vertical Structure
Lee, Kwang Ho ; Kim, Chang Hoon ; Kim, Do Sam ; Hwang, Young Tae ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 473~482
This study numerically discusses wave forces acting on a vertical wall such as breakwaters or revetments, subjected to incident undular or turbulent bores. Due to the complex hydrodynamics of bore, its wave forces have been predicted, mainly through laboratory experiments. Numerical simulations in this paper were carried out by CADMAS-SURF(CDIT, 2001), which is based on Navier-Stokes momentum equations and VOF method (Hirt and Nichols, 1981) for tracking free water surface. Its original source code was also partly revised to generate bore in the numerical water channel. Numerical raw data computed by CADMAS-SURF included great strong spike phenomena that show the abrupt jumps of wave loads. To resolve this undesired noise of raw data, the band-pass filter with the frequency of 5Hz was utilized. The filtered results showed reasonable agreements with the experimental results performed by Matsutomi (1991) and Ramsden (1996). It was confirmed that CADMASSURF can be applied to the design of coastal structures against tsunami bores. In addition, the transformation process and propagation speed of bores in the same 2-d water channel were discussed by the variations of water level for time and space. The numerical results indicated that the propagation speed of bore was changed due to the nonlinear interactions between negative and reflected waves.
A Study on Controlling Efflux Sediment Diffusion by Jetty Construction at Small Estuary
Park, Sang Kil ; Park, Hyun Su ; Yoon, Jong Su ; Lee, Si Ho ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 483~491
In this study, a jetty construction is taken into account for the reduction of sediment diffusive concentration incoming from the upstream river due to the urbanization and industrial development and to minimize the effects on the coastal ecosystems. The field observation and numerical calculation are conducted to analyze the diffusion zone of sediment concentration in the small estuary and coastal area. The specification of the installed jetty which is able to control the sediment concentration was decided based on the prediction of the dispersion area changes in space and time. The selected size and layout for the jetty design were examined for the dispersion zone by numerical calculation and field observation. As a result, the jetties constructed in the estuary retarded the dispersion rate of sediment concentration, so that the effect area of sediment dispersion was obviously decreased. In addition, the measured field data indicated that the sediment deposition in the inside of dikes could be controlled and the right side area of jetties could be preserved without influx sediment diffusion.
Derivation of Extended Mild-Slope Equation Using Euler-Lagrange Equation
Lee, Changhoon ; Kim, Kyu-Han ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 493~496
In this study, we derive the extended mild-slope equation in terms of the velocity potential using the Euler-Lagrange equation. First, we follow Kim and Bai (2004) who derive the complementary mild-slope equation in terms of the stream function using the Euler-Lagrange equation and we compare their equation to the existing extended mild-slope equations of the velocity potential. Second, we derive the extended mild-slope equation in terms of the velocity potential using the Euler-Lagrange equation. In the developed equation, the higher-order bottom variation terms are newly developed and found to be the same as those of Massel (1993) and Chamberlain and Porter (1995). The present study makes wide the area of coastal engineering by developing the extended mild-slope equation with a way which has never been used before.
Wastewater Treatment by using a Rotating Photocatalitic Oxidation Disk System
Chung, Ho Jin ;
Journal of The Korean Society of Civil Engineers, volume 29, issue 5B, 2009, Pages 497~502
The wastewater treatment by photocatalyst decomposes pollutants directly in water, and it is easy to decompose indecomposable organics and inorganic. and Especially, it has an advantage that there is no secondary production of pollutants. However, there will be many problems which are generated depending on the type of photocatalyst. The type of rotating photocatalyst minimizes previous problems, and advanced oxidation processes is possible by the application of rotating disc method. The consideration of the characteristics about various designs and operation factors is needed for the application of rotating photocatalyst system. In this study, rotating photocatalyst was manufactured for rotating disc method by fixing of
. The operation factors were derived for the wastewater treatment by the reaction of rotating photocatalyst. The contained quantity of
was limited about 70%. The more the contained quantity of
was increased, the more the treatment rate was continually increased. The optimum rotating photocatalyst was R4, and the contained quantity of
was 36.8%. The more the exposed amount of UV is increased, the more the decomposition effect of TCODcr was continually increased. However, the adequate strength of light source must be determined by the consideration of economical efficiency. The more the speed of rotating photocatalyst is increased, the more treatment efficiency was increased. When UV lamp was not submerged in reactor, the wastewater treatment was efficient in the order of the depth of water 50%, 30%, 10%, 70%, 100%. This study is a basic research for the development of a system which treats organics in solar light.