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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 24, Issue 6D - Nov 2004
Volume 24, Issue 6C - Nov 2004
Volume 24, Issue 6B - Nov 2004
Volume 24, Issue 6A - Nov 2004
Volume 24, Issue 5D - Sep 2004
Volume 24, Issue 5C - Sep 2004
Volume 24, Issue 5B - Sep 2004
Volume 24, Issue 5A - Sep 2004
Volume 24, Issue 4D - Jul 2004
Volume 24, Issue 4C - Jul 2004
Volume 24, Issue 4B - Jul 2004
Volume 24, Issue 4A - Jul 2004
Volume 24, Issue 3D - May 2004
Volume 24, Issue 3C - May 2004
Volume 24, Issue 3B - May 2004
Volume 24, Issue 3A - May 2004
Volume 24, Issue 2D - Mar 2004
Volume 24, Issue 2C - Mar 2004
Volume 24, Issue 2B - Mar 2004
Volume 24, Issue 2A - Mar 2004
Volume 24, Issue 1D - Jan 2004
Volume 24, Issue 1C - Jan 2004
Volume 24, Issue 1B - Jan 2004
Volume 24, Issue 1A - Jan 2004
Selecting the target year
Modeling Mixing Behavior of Ocean Outfall Systems by Interfacing Zonal Models
Kim, Young-Do ; Seo, Il-Won ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 391~401
A hybrid model was developed to predict the initial near field mixing and the far field transport of the buoyant jet discharged from the submerged wastewater outfall. The sensitivity analysis with the analytical solution and experimental data allows that base spreading coefficient in the jet integral model is chosen to be 0.109, and the grid sizes of
in the particle tracking model make less error independent of particle numbers. The length scale model with the line plume approximation makes good agreement in the minimum dilution and initial mixing length when the range of the riser spacing of the rosette diffusers is
. The developed particle tracking model simulate the advection-diffusion process very well in the
grid system. Comparing with the experimental results, the proposed hybrid model properly predict both the near field mixing and the far field transport with various effluent and ambient conditions. The result of the model application to the Masan outfall show that the bottom concentration near the diffuser is smaller when the jet integral model is used instead of line-plume approximation.
Redefining of Parameters of Nakayasu Synthetic Unit Hydrograph
Yoon, Tae-Hoon ; Kim, Sung-Tak ; Kim, In-Dong ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 403~412
By making use of the basin characteristics and the representative unit hydrographs at the gaging stations in Korea, the parameters of the Nakayasu synthetic unit hydrograph were redefined resulting in modified Nakayasu synthetic unit hydrographs. Hydrological homogeneity studies made in terms of rainfall pattern and river basin characteristics reveal that both the Seomjin River and the Youngsan River basins have distinct difference to the remaining basins in Korea. Different river basin characteristics in Korea and Japan brings about significant changes in the parameters of the Nakayasu synthetic unit hydrograph and it calls for modified Nakayasu synthetic unit hydrographs for its application to river basins in Korea. The modified Nakayasu unit hydrographs are proved to render significantly improved runoff estimates in terms of peak runoff and time to peak compared with the original Nakayasu synthetic unit hydrograph. Meanwhile, in both the Seomjin River and the Youngsan River basins, basin-wise modified Nakayasu synthetic unit hydrographs show notorious improvements almost identical to the representative unit hydrographs, which are in the vein of the inhomogeneous basin characteristics.
Estimation and Analysis of Precipitatable Water
Yoo, Chul-Sang ; Shin, Chang-Kun ; Yoon, Yong-Nam ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 413~420
Precipitable water is the moisture content within the air represented by the water depth, which is an important information for the analysis of land-atmospheric interaction and local hydrometeorologic change. However, as the measurement itself is very expensive, so only limited information in some locations is available, thus, its indirect estimation is required in other places. This study tries to fine out the most correlated meteorological factors and to compare their characteristics. This study analyzed the precipitable water data measured at the Osan station in 2000, along with the meteorological factors like precipitation, temperature (minimum, maximum, and average), humidity (minimum, maximum, and average), and the dew point temperature measured at the Suwon station, The results derived from the analysis are as follows. (1) Precipitable water is found highly correlated with the temperature (correlation coefficient 0.806 with the daily maximum temperature, 0.883 with the daily minimum temperature, and 0.875 with the dew point temperature), but less correlated with the humidity with the correlation coefficient less than 0.5. Especially the correlation coefficient with the daily low temperature is found to be higher than that with the dew point temperature. (2) Precipitable water shows an obvious seasonality like the precipitation, whose variability seems to be the same order of its mean value. (3) A strong short period of seven days could be found in the spectrum analysis of the precipitable water. The same could also be found in the dew point temperature data, which seems to be an effect of very regular three-cold and four-warm days pattern in winter.
Estimation of Reflection and Transmission Coefficients with Finite Element Method
Jeong, Woo-Chang ; Heo, Bo-Young ; Song, Jai-Woo ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 421~429
This paper presents a numerical analysis on the spatial behaviors of fluid and solute in a single fracture with anisotropic variable apertures. The spatial correlated aperture field is generated by using a geostatistical method. In this study, two cases are considered: 1) the increase of correlation length along the flow direction,2) the increase of correlation length along the vertical direction of flow. When the correlation length increases along the flow direction, the flow rate increases more or less linearly but the flow tortuosity tends to decrease. The arrival time and peak time of solute transport are increasingly faster but its spatial dispersion decreases. When the correlation length increases vertically against the flow, the flow rate has a tendency to decrease, but the flow tortuosity increases. The arrived time and peak time of solute transport are increasingly delayed, and the spatial dispersion tends to decrease. Consequently, it is shown that the fluid flow and solute transport are significantly affected by the anisotropic degree of variable aperture distribution.
Simulation of Daily Precipitation Data Using Nonhomogeneous Markov Model I -Theory
Moon, Young-Il ; Cha, Young-Il ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 431~435
This paper presents nonhomogeneous transition probabilities to describe nonhomogeneous status based on nonhomogeneous Markov chain's systematic concept using a expanded nonparametric kernel density function method. The daily transition probability matrices are estimated nonparametrically. A kernel estimator is used to estimate the transition probabilities through the weighted average of transition counts over a symmetric time interval centered at the day of interest. Thus, a wet day is decided by the nonhomogeneous transition probabilities. The precipitation amounts on each days of interests are decided form the kernel density function estimated from all wet days that fall within a time interval centered on the calendar day of interest over all the years of historical observations.
Simulation of Daily Precipitation Data Using Nonhomogeneous Markov Model II - Application
Moon, Young-Il ; Cha, Young-Il ; Seoh, Byung-Ha ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 437~441
In this paper, we simulates the daily precipitation by using the nonhomogeneous Markov chain model to extend or fill out the missing values. The daily transition probability of a nonhomogeneous Markov model is applied to precipitation station in Seoul. Precipitation data are obtained by using the probability density function(PDF) of the kernel function of the recorded data. Nonhomogeneous Markov chain model theory does not provide problems of daily transition probability composition even when the data length was short. Simulated daily precipitation data from the preserves the frequency structure of the wet spell length, dry spell length, and wet day precipitation at both seasonal and annual time scales.
Development of an Operating Model for Hwacheon Dam Considering Emergency Spillway Gate and Imnam Dam
Shin, Hong-Joon ; Kim, Tae-Soon ; Heo, Jun-Haeng ; Yoon, Taek-Ki ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 443~452
This study investigated the hydrological effects of Imnam Dam to Peace and Hwacheon Dams and then developed a new operating model for Hwacheon Dam by considering Imnam Dam. The construction of Imnam Dam resulted in decreasing of inflow to Peace Dam and in increasing the capacity of flood control of Peace Dam. However, it gave little effect to the capacity of flood control of Hwacheon Dam. After construction of Imnam Dam, in the case of PMP, Peace Dam has no problem while Hwacheon Dam has a critical problem. In such a case, if the five emergency spillway gates of Hwacheon Dam are used for fast release, then the water level can be lowered below the flood water level. In addition, the flood control water level can be increased based on the simulation by using the emergency spillway gates.
The River Flood Runoff Forecasting using GA and T-S Fuzzy System
Lee, Kwan-Soo ; Park, Sung-Chun ; Hong, Chang-Oh ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 453~460
Recently, it is advised that a flood-runoff be understood by analysing the rainfall-runoff of a specific area to reduce the damage of natural disasters such as floods, typhoons, etc. Nevertheless it is not easy to explain the rainfall-runoff which is non-linear, time-varying and distributed in space as simple model but also has many errors. However, now we can explain complex non-linear processes thanks to the development of an artificial intelligence like a neural network, a fuzzy logic, an AI expert system and a genetic algorithm. Yet, it is expected that the AI, the neural network, the fuzzy logic, the AI expert system and the genetic algorithm have to be used more effectively and be united to actualize the AI. In the study, the genetic algorithm is used for a method to optimize the triangular membership function form and the rule base of the T-S Fuzzy system, which is used for a forecast. Seonam and Naju water gauge station near the Youngsan water system are selected for the study. The average rainfalls of water basins through the Thiessen method and the discharge data through the rating-curve equation are used for the combination of the genetic algorithm and T-S fuzzy system. The result of flood-runoff forecast is so excellent by the combination of them. As a result, it is thought that the prediction for the time after 3 hour or 4 hour done in the study could be substitution for the flood forecasting system.
Orographic Effect Estimation of Rainfall in Han River Basin - 3. Regionalization-
Kim, Kee-Wook ; Yoo, Chul-Sang ; Jun, Kyung-Soo ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 461~468
Yoo et al. (2004a, b) did the linear regression analysis, non-linear regression analysis, and EOF analysis of rainfall in the Han river basin with respect to the elevation and concluded the existence of orographic effect. Especially, the rainfall at the elevation of 600 m has found to be rather high and its variability also to be sensitive to the topographic effect. However, it is also generally accepted that the orographic effect cannot be explained only by the elevation, but many others intermingled altogether. This study is on line with the work by Yoo et al. (2003b) and used the Varimax Method of using Component Correlation Vector for regionalizing the nu river basin. The regionalization here is based on the spatial-temporal variability of rainfall, thus the result derived is to count for relative amount of orographic effect, not for dividing the plain and mountain region. This study analyzed five rainfall events which were concluded to have rather large orographic effect in Yoo et al. (2003b). The results derived are as follows. (1) Each rainfall event shows a different of regionalization result. That is, the orographic effect is different from event to event. (2) The south-eastern part of the Han river basin around Daekwanryung (its elevation over
) is distinguished from other regions. This are seems to have most obvious orographic effect within the Han river basin.
Nitrogen Removal and Microbial Granulation in Anaerobic Processes
Ahn, Young-Ho ; Kim, Hee-Cheul ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 469~476
The sustainable anaerobic nitrogen removal and microbial granulation were investigated by using three laboratory anaerobic granular sludge bed reactors, treating synthetic (inorganic and organic) wastewater and piggery waste. From inorganic synthetic wastewater, lithoautotrophic ammonium oxidation to nitrite/nitrate was observed by an addition of hydroxylamine. Also, the results revealed that the Anammox intermediates (particularly, hydrazine) contents in the substrate would be one of important parameters for success of the anaerobic nitrogen removal process. The results from organic synthetic wastewater shows that if the Anammox organism were not great enough in the startup of the process, denitritation and anaerobic ammonification would be a process prior to the Anammox reaction. The anaerobic ammonium removal from the piggery waste was performed successfully, probably due to the Anammox intermediates contained in the substrate. This reactor shows a complex performance including the Anammox reaction and HAP crystallization, as well as having partial denitritation occurring simultaneously. From the activity test, the maximum specific N conversion rate was
(0.77 g T-N/g Vss/day), indicating that potential denitritation is quite high. The
ratio to Anammox is 1.17. The colour of the biomass treating the piggery waste changed from black to dark red. It was also observed that the red-colored granular sludge had a diameter of
. The settleability assessment of the granular sludge revealed that the granular sludge had a good settleability even though it was worse than that of seed granular sludge.
Hydraulic and Hydrologic Dam Risk Analysis (I) - Development of Dam Risk Analysis Methodology Using Nonparametric LHS-Monte Carlo Simulation -
Moon, Young-Il ; Kwon, Hyun-Han ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 477~487
The dam overtopping probability using parametric Monte Carlo Simulation(MCS), which revealed a weakness as being the hardest problem in analysis techniques, cannot define correct probability distribution about hydraulic/hydrological uncertainty variables. Nonparametric MCS reflect probability characteristics of data relatively well comparing parametric method. Another problem of existing MCS generates a large number of realizations of uncertainty variable according to their corresponding probability distribution. Therefore, overall objective of the present study is to formulate a practical methodology to evaluate, systematically and quantitatively, the risk of failure in an existing dam.
Hydraulic and Hydrologic Dam Risk Analysis - Application of Dam Risk Analysis -
Moon, Young-Il ; Kwon, Hyun-Han ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 489~500
The risk assessment models for dam are developed by using nonparametric LHS-Monte Carlo Simulation(MCS). This paper examined appropriateness of model for the existing earth dam and this study select USBR Tier-2 dam safety guideline as dam risk criterion. The nonparametric LHS-MCS dam risk analysis model presented reliable overtopping probability and a good analysis ability compared with existing parametric dam risk analysis model.
Applicability of High Resolution Climate Model for Watershed Scale Analysis
Jeong, Chang-Sam ; Heo, Jun-Haeng ; Bae, Deg-Hyo ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 501~508
Applicabilities of high resolution climate model simulation were analyzed for Korean watersheds. Coarse resolution climate model has been used, but recently high resolution climate model started to be generated by the rapid progress of computational ability. Adopted climate model in this study is Metri-AGCM (
) which has
spatial resolution and run by the METRI (Meteorological Research Institute). Surface precipitation and temperature information were extracted for the indicator variable and the observed mean areal precipitation, temperature, and discharge data were also used for the target variable. Preliminary test which uses mean and standard deviation analysis was proposed and applied before adopting the probabilistic diagnostic method. And the preliminary analyses were compared with the result of probabilistic diagnostic method. Results show that Metri-AGCM (
) has high applicabilities for the watersheds of Korea. Especially it can discriminate temperature information for all basins very effectively. In addition, precipitation and discharge data are also applicable for some cases.
Aanalysis of Anoxic Phosphorus Uptake in BNR Process Using the Microbial Characteristics
Lee, Sang-Hyung ; Jeong, Hyeong-Seok ; Park, Myung-Gyun ; Shin, Hang-Sik ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 509~514
In the full scale DNR process using domestic sewage, organic matter, nitrogen and phosphorus were removed effectively. The nitrate removal rate at the anoxic state increased by about 12% over the theoretical value due to the anoxic P-uptake mechanism. As the organic matter fed, the glycogen content of the bio-P bacteria declined and the concentration of PHAs (polyhydroxyalkanoates) increased at the anaerobic state from 2.2 to 10 mgC/gVSS. After that, PHAs were reduced inside the PAO(phosphorus accumulating organism) whereas the glycogen content was found to increase slightly at the anoxic and aerobic stages. Also, the degraded poly-P at the anaerobic stage was resynthesized within the cells of the PAO for phosphorus uptake at the anoxic and aerobic stages. The bacterial species composition of the full scale DNR system clones were within the beta subclass, and belonged to two genera: Rhodocyclus and Nitrosomonas. Rhodocyclus sp. (92% identity) a member of the group called DPB (denitrifying phosphorus removing bacteria) existed in the anoxic state, meaning that nitrate removal by denitrifying dephosphatation was conducted.
Effects of DO Concentration and Aeration Time on the Conversion of Ammonium to Nitrite
Park, Hung-Suck ; Jeong, Seong-Mo ; Kim, Jung-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 24, issue 5B, 2004, Pages 515~520
The effects of DO and aeration time, traditional nitrification inhibition factors, on nitrite (
) accumulation were studied to find the practical nitrite build-up conditions. The effect of DO on nitrite build-up was studied in 21 lab-scale SBRs at DO 2.5 mg/l and 1.0 mg/l. The ammonium oxidizer was not inhibited at DO 2.5 mg/l and DO 1.0 mg/l, while nitrite oxidizer was inhibited at DO 1.0 mg/l. That results showed that nitrite oxidation rate of DO 1.0 mg/l was 16% lower than that of DO 2.5 mg/l. To certify the optimum aeration condition for nitrite build-up, experiments were conducted by changing aeration time at DO 1.0 mg/l. The optimum condition for nitritation was 2 cycles per day of 2 hr aeration-9 hr anoxic condition, at which influent ammonium ion (
) was removed 99.9% and 82% of the removed nitrogen was converted to nitrite. However, 50% of the influent ammonium ion was removed and 95% of the removed nitrogen was accumulated as nitrite at 1 cycle per day of 3 hr aeration-19 hr anoxic condition.