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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 19, Issue 3_6 - Nov 1999
Volume 19, Issue 2_6 - Nov 1999
Volume 19, Issue 1_6 - Nov 1999
Volume 19, Issue 3_5 - Sep 1999
Volume 19, Issue 2_5 - Sep 1999
Volume 19, Issue 1_5 - Sep 1999
Volume 19, Issue 3_4 - Jul 1999
Volume 19, Issue 2_4 - Jul 1999
Volume 19, Issue 1_4 - Jul 1999
Volume 19, Issue 3_3 - May 1999
Volume 19, Issue 2_3 - May 1999
Volume 19, Issue 1_3 - May 1999
Volume 19, Issue 3_2 - Mar 1999
Volume 19, Issue 2_2 - Mar 1999
Volume 19, Issue 1_2 - Mar 1999
Volume 19, Issue 3_1 - Jan 1999
Volume 19, Issue 2_1 - Jan 1999
Volume 19, Issue 1_1 - Jan 1999
Selecting the target year
Remote Sensing Data and Geographic Information System Applications to Improve the Input Data Generation Method of Water Pollution Simulation Model
Lee, Beum-Hee ; Lee, Kil-Seong ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 125~125
It is very important to select appropriate methods of collecting, predicting, and analyzing information for the development of urban water resources and the prevention of disasters. The management of water resources is further more difficult in both parts of water quality and quantify as the urbanization accompanied by population growth, industrialization, and water pollution goes forward. Thus, an accurate data generation method is developed in this study using the Geographic Information System (GIS) and Remote Sensing (RS). The urban runoff and non-point source pollution are simulated by SWMM in the An-Yang cheon watershed as a study area representing a Korean urban stream with several tributaries. The time-varying data in a large region were reasonably obtained by the application of the GIS using ARC/INFO and RS data. The simulated results showed agreement with the measured data globally. These methods are expected to simulate the runoff and water quality efficiently in the rapidly varying urban area.
A Study on Automatic Parameter Estimation for a Nonlinear Time-continuous Runoff Model
Bae, Deg-Hyo ; Heo, Jun-Haeng ; Chung, Jun-Seok ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 139~139
The objective of this study is to provide an effective parameter estimation scheme for a physically-based nonlinear runoff model with multiple parameters. The scheme is based on initial estimation for the model parameters containing physical meanings from the observed hydrologic, meteorological data and automatic estimation for the more detail parameters of Sacramento model by the Downhill Simplex method. The selected two study areas are Pyungchang and Naerinchen River basins, and 10-year, 7-year daily data are used for model calibration and verification, respectively. The model performance on correlation coefficient between observed and computed flows for the verification periods was above 0.83. Comparison between the estimated parameter values by the initial estimation and those by the automatic estimation shows that good initial estimates are valuable, but automatic scheme should be followed from the initial one.
Investigation of Nonlinearities for El
Kim, Hung-Soo ; Ahn, Jae-Hyun ; Yoon, Yong-Nam ; Park, Moo-Jong ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 149~149
We assume that the SOI which is associated with El
has a linear characteristics and is fitted to ARMA model. The model is verified from the ACF, the PACF and Porte Manteau test on the residuals for its validity. However, the hypothesis of randomness is not accepted from a new test technique. called the BDS statistic. This means that ARMA model is not appropriate for the SOI data and this is due to the nonlinearity of time series. The Close Returns Test is used for searching for chaos, which has the nonlinear deterministic characteristics of time series and it is found that there is no evidence of deterministic chaos in the SOI data Therefore, we can consider that the nonlinear techniques such as nonlinear stochastic models or neural networks may be more valid for the SOI series.
Logarithmic Friction Factor Equations of Open Channel Flow
Yoo, Dong-Hoon ; Lee, Min-Ho ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 159~159
Many researchers proposed the equations of friction factor or mean velocity for open channel flow. The existing equations were developed with the coefficient of equivalent roughness height or based on the assumption of rough turbulent flow. In open channel flow, however, from Varwick's laboratory data there are found several characteristic flows such as laminar flow, smooth turbulent flow, transitional turbulent flow and rough turbulent flow. In order to imply all the characteristics of such flow, the present workers developed the logarithmic equation of friction factor for smooth turbulent flow and rough turbulent flow in open channels and further developed explicit equations for smooth turbulent flow by adjusting several parameters.
The Development of Design Low-flow Estimation Model at the Ungaged Mountainous Watershed
Lee, Jae-Hyoung ; Cho, Gle-Tae ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 169~169
The purpose of this study is to estimate the design low-flow statistics(DLFS) at the ungaged mountainous watershed. The formulation for the estimation of the design low-flow statistics is obtained by the means of the stream-aquifer hydraulic approach applied to a mountainous watershed. Three independent variables associated with the low-flow statistics is the watershed area(A), the average basin slope(S) and the base flow recession constant(
); The watershed area is measured from 1:25,000 scale topographic maps and the average basin slope is estimated by Strahler's slope determining method. And the base flow recession constant is computed by Vogel and Kroll's method. The recession constant at the ungaged sites is estimated by our proposed method. The model for estimating low-flow statistics is applied to 61 outlets of our chosen catchments in the Sumjin, Mankyung and Youngsan basin. The regional formula to estimate the DLFS at the ungaged point is proposed.
The Half-loc : Optimized Middle Armor Block
Kweon, Hyuck-Min ; Lee, Dal-Soo ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 183~183
The rubble mound coastal structures covered with artificial armor units have been accepted worldwide. However, since it is hard to obtain big stones in the field, the stones placed under the first layer of Tetrapod, Dolos, Accropode, Core-loc etc. do not usually satisfy the design requirement of weight in the case of large waves. This circumstance has required the development of a middle block. The middle armor units described in this paper is named as Half-loc. In order to investigate the stability of Half-loc slope, two different experiments have been conducted. In the first experiment, the Half-locs exclusively composing the upper layer, were exposed directly to waves, and useful information regarding the stability of the units during construction were obtained. In the other experiment, four different combinations in weights of Tetrapods and Half-locs were used. According to the first experiment, the exposed Half-loc shows the stability coefficients,
(Hudson,1969), of 4.5 and 10 depending on the methods of placement. The second experiment revealed that the rubble mound slope covered with Tetrapods in the range of 3 to 10 times heavier than Half-locs were stable. The present study shows that the Half-loc can replace the stones in the secondary layer, and as a consequence, can improve the stability of a rubble mound section and reduce construction time.
Prediction of Water Quality in Osip River
Jang, Tae-Yeon ; Kim, Sung-Tae ; Min, Seon-Hong ; Kim, Geon-Heung ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 195~195
In this study, the fundamentals of environmental information system as well as its development strategy were presented. The proposed system was applied to the Osip river in Samchuck, Kwangwon province. The estimation of pollution discharge to the Osip river was performed by the GIS which was developed to collect the geographically related pollution data. In applying the GIS, the digital maps such as topography, land use, and so on were generated and attribute data were stored. Using the generated or collected data, the prediction of water quality was performed through the QUAL2E. It was found that the water quality in the Osip river was currently in 4th grade at Dogae, but 3rd grade in downstream, and 4th grade in estuary. The experiments showed that the BOD, SS, T-N, and T-P at Dogae in 1996 will be increased to 12%, 16%, 7%, 16% in 2001 and 22%, 30%, 13%, 26% in 2006, respectively. In case of estuary, the BOD, SS, T-N, and T-P will be increased to 20%, 28%, 11%, 28% in 2001 and 58%, 70%, 36%, 65% in 2006, respectively. Conclusively, the result of the experiments could be utilized to locate and manage the environmental pollution management facilities such as municipal wastewater treatment plant.
Steady-state Behavior of the Continuous Flow Intermittent Decant Activated Sludge Process for Biological Nutrient Removal
Ahn, Kyu-Hong ; Lee, Hyung-Jib ; Eum, Young-Jin ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 207~207
This research examined behavior of nutrient conversion during steady-state operation of continuous flow intermittent activated sludge process. Two reactors were operated parallel and acetate was injected into the sludge layer during settling and decanting periods in order to investigate the phosphorus release and denitrification in the process. Such scheme effectively induced P-release inside the sludge layer and excess P-uptake during the subsequent aeration period for phosphorus removal. From the relationship between nitrification and phosphorus removal, nitrification with high rate resulted in high nitrate concentration and this caused the inhibition on phosphorus release from the sludge layer during anaerobic period. Nitrate in the sludge needed to be denitrified in the anoxic settling period before effective phosphorus release could take place. In the initial point of settling period, the nitrate concentration in the reactor with acetate injection was quite different from one in the reactor without it. 25 minutes of lag-time was observed in phosphorus release after the introduction of acetate and most of phosphorus release occurred during the decanting period. The DO concentration should be maintained at the optimum range (0.5-1.0 mg/L) during the aeration period for phosphorus removal. It was also found that increased pH drop and higher influent pH had effect on increased effluent orthophosphate concentration.
Life Cycle Assessment on the Residential Solar Energy Systems for Reducing the Greenhouse Gases
Seo, Seong-Won ; Hwang, Yong-Woo ; Tak, Seong-Je ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 215~215
Recently, the concern about solar energy as an alternative energy source is on the rise with the outstanding of global environmental issues due to the massive consumption of fossil fuel. In this paper, residential photovoltaic(PV) power supply system equipped with poly-crystalline silicon (poly-Si) PV module, and hot water supply system using solar energy are evaluated throughout their life cycle. In addition, the
emission in residential building applying the above two solar energy systems was evaluated as an application case. As the results, the
emission from a 3kWp residential PV power system have ranged from 3.4 ton carbon(ton-C) to 6.7 ton-C according to the production scale and installation stage. The amount of
reduction in the using stage was 0.7 ton-C per year. In hot water supply system (tank capacity 170L), on the other hand,
emission was 0.1ton-C in the production and installation stage, and the amount of
reduction in the using stage have ranged from 0.1 ton-C to 0.2 ton-C according to the hot water energy resources. Consequently, it was possible to recover the
emission from the stage of production and installation with only 1 year-use.
Microfiltration of Septic Tank Effluent for Wastewater Reuse
Ahn, Kyu-Hong ; Song, Kyung-Guen ; Yeom, Ick-Tae ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 225~225
Experiments were conducted to evaluate the applicability of microfiltration in treating septic tank effluent for reuse. The basic factors for design and operation of the system were determined. A hollow fiber microfiltration membrane was used in the pilot test. The pore size of the membrane was
and effective surface area was
. The maximum capacity of the pilot plant was
. The microfiltration system was able to be operated for 120 days without chemical cleaning. But the optimum period of chemical cleaning was found to be shorter than 70 days for control of fouling and permeate flux. It was also found that agitation in membrane tank had effect on fouling prevention. In particular, alternating the direction of agitation significantly reduced the proceeding of fouling. Chemical cleaning was effective in recovering of permeate flux and resistance. But complete recovery of the membrane to its initial condition in terms of resistance could not be attained by chemical washing. Based on mass balance analysis, about 60% of TOC mass removal in the system was attributed to biodegradation, indicating the important role of biodegradation even in the system without any biological process. But suspended solids and colloidal matter were removed by sieve mechanism of membrane. Permeate quality was found to be lower than 30mg/L of COD, 10mg/L of BOD, 10mg/L of TOC, 1 NTU of turbidity and 2mg/L of SS, respectively. It satisfies standard for wastewater reclamation.
Considerations for the Optimum Design and Operation of Coagulation Process in Water Treatment Plant
Han, Moo-Young ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_2, 1999, Pages 239~239
Coagulation process is one of the most important processes in WTP. The optimum design and operation of coagulation process is vital to the economic production of safe and clean drinking water. If the coagulation process is operated out of the optimal range, the plant tends to overdose the coagulant, resulting in the high chemical cost, large sludge production, high labor cost and possible high aluminum concentration in the drinking water. Generally, the only solution toward the optimal operation of WTP has been focussed in the change of type and/or dosage of coagulant or change of the mixing intensity. However, the inherent problem due to the deficiency in the design process can not be solved by these practice. The problem can only be solved by the understanding of the process through careful investigation of the design and scientific analysis of operational data. In this paper, a summary of the 3 year research on the coagulation process is presented. The design standard and its application policy of both Korea and USA are compared. Design deficiencies of flash mixer, distribution channel, and flocculation basin is proved by the theory and field measurement. The zeta potential was measured and G value was compared and particle counter was used. Several pilot plant experimental data are compared to prove the problems of existing plants. New operational methods such as SCM, pilot filter, and zeta potential are introduced and the experience of using those control techniques at the existing plants are presented. The result presented in this research will be helpful to understand the current problems in using the design standard of Korea, evaluate the coagulation process in existing water treatment plants, and suggest the modification of that process. Hopefully, it will lead toward the production of safe and cheap drinking water and ultimately toward the re-evaluation of the great value of clean drinking water and the people working in this field which they deserve.