• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.40-43
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• 2006

Public demand for the heat pump system as a next generation energy equipment is increasing for its eco-friendly and cost-effective advantage. Many researches have been concentrated on how to calculate and develop its own efficiency, while the possible effect of the heat pump operation on the whole subsurface temperature distribution is relatively less considered, During the current study, subsurface temperature disturbance caused by seasonal surface temperature cycle in Busan area and general W-tube heat pump operation is simulated in 3-dimensional heterogeneous medium. It shows that subsurface deeper than 10m from the surface remains nearly unchanged throughout the 4 seasons and groundwater convect ion in highly permeable layer near the surface acts like a main path of heat plume from heat pump system, This implies the significance of detail descript ion in shallow sedimentary layer or highly permeable layer which plays an important role on the regional flow advection and heat transfer. Also, the effect of groundwater convection increases when the arrangement of the 2 injection pipes and 2 extract ion well is maintained parallel to groundwater flow. Therefore, more careful and detail investigation is required before installation and operation of heat pump system that it may not cause any possible change of microbial ecosystem in the shallow subsurface environment or 'contamination of temperature' for groundwater use as well as the loss of efficiency of the equipment itself. This can also help to design the optimized grouting system for heat pump.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.581-591
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• 2016

Several attempts to construct multi-purpose tunnel for both road and waterway have been made. The multi-purpose tunnel is mainly used as a road tunnel, however it is transferred to waterway to control flood during rainy season. The planning of the multi-purpose tunnel is recognized as cost-effective way of infrastructure construction. In case of the multi-purpose tunnel constructed beneath groundwater table, seasonal fluctuation of groundwater table and repeated flow in the tunnel may cause long-term deterioration of the tunnel system. In this study, the behavior of multi-purpose tunnel in view of groundwater table or flow in the tunnel is investigated using model test and numerical modeling method. The results have shown that rising of groundwater table caused buoyant force to the tunnel and the fluctuation of rainwater in the tunnel generated loosening of surrounding ground. It is recommended to evaluate the effect of the long-term water pressure variation in the design of a multi-purpose tunnel.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.786-789
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• 2002

A recurrent artificial neural network (ANN) model is developed to simulate hydrocarbon recovery process at petroleum-contaminated site. The groundwater extraction rate, vacuum pressure, and saturation hydraulic conductivity are selected as the input variables, while the cumulative hydrocarbon recovery volume is considered as the output variable. The experimental data fer establishing the ANN model are from implementation of a multiphase flow model for dual phase remediation process under different input variable conditions. The complex nonlinear and dynamic relationship between input and output data sets are then identified through the developed ANN model. Reasonable agreements between modeling results and experimental data are observed, which reveals high effectiveness and efficiency of the neural network approach in modeling complex hydrocarbon recovery behavior.

• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.869-877
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• 2015

Freshwater may be injected into aquifers to combat sea water intrusion in groundwater or to store water for later retrieval. For these cases to achieve the desired goal groundwater modeling is commonly used to determine locations and rates of injection wells. When these wells are connected to a pipe network, a flow control valve is installed for each well to regulate the injection rate. When a valve opening is modified, pressure changes in the entire pipe network and thereby changes flow rates in other wells. Therefore, desired valve openings must be determined for all injection wells. The pipe flow analysis allows estimation of the minimum pump power in addition to valve openings. Methods are developed to identify valve openings for multiple wells and the minimum pump power. The methodology developed in this work can contribute to precise operation of multiple injection wells.

• Journal of Environmental Science International
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• v.27 no.10
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• pp.831-844
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• 2018

Riverbank Filtration (RBF) is a kind of indirect artificial recharge method and is useful in obtaining higher-quality source water than surface water when procuring municipal water. This study evaluated optimal riverbank filtered water and the productivity of the radial collector wells on Ttansum Island in the area downstream of the Nakdong River, where Gimhae City is constructing a municipal water plant for the purpose of acquiring high-quality water. The RBF wells are planned to provide water to the citizens of Gimhae City through municipal water works. Groundwater flow modeling was performed with the following four scenarios: (a) 9 radial collector wells, (b) 10 radial collector wells, (c) 10 radial collector wells and two additional vertical wells, and (d) 12 radial collector wells. This study can be useful in determineing the optimum production rate of bank filtrated water not only in this study area but also in other places in Korea.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.24-31
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• 2005

This study presents a contaminant transport model suitable for a 2-dimensional heterogeneous aquifer with multiple contaminant sources. It uses a streamline simulation, which transforms a multi-dimensional problem into multiple 1dimensional problems. It runs flow simulation, streamline tracking, and calculation of contaminant concentrations by turns. The model is verificated with a Visual MODFLOW by comparing contaminant concentration distributions and breakthrough curves at an observation well. Due to its fast simulation, it can be applied to time consuming simulations such as in a fine-grided aquifer, an inverse modeling and other applications.

• Korean Journal of Hydrosciences
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• v.3
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• pp.105-113
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• 1992

Various modeling approaches to study a long term behavior of streamflow or groundwater storage have been conducted. In this study, a Multivariate AR (1) Model has been applied to generate monthly flows of the one key station which has historical flows using monthly flows of the three subordinate stations. The Model performance was examined using statistical comparisons between the historical and generated monthly series such as mean, variance, skewness. Also, the correlation coefficients (lag-zero, and lag-one) between the two monthly flows were compared. The results showed that the modeled generated flows were statistically similar to the historical flows.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.74-77
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• 2000

Infiltration and water flow in the upper soil layer of a deep water table aquifer are modeled for multistorm runoff events. The infiltration process is developed using the sharp wetting front model of Green and Ampt, and the following redistribution process is modeled using the gravity drained rectangular approximation. The Brooks-Corey model [Brooks and Corey, 1966] is adopted to relate the effective soil saturation, the tension head, and the unsaturated hydraulic conductivity Firstly, the infiltration and redistribution model is developed for a single stom runoff event. Then a couple of events combined for multistorm runoff events. In the later case, infiltration rate of the second rainfall is strongly influenced by the length of the rainfall hiatus and soil moisture profile.

• Water Engineering Research
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• v.1 no.3
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• pp.243-256
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• 2000

This physically-based hydrologic model is developed to calculate the soil-moisture balance on paddy fields. This model consists of three modules; the first is the unsaturated module, the second is the rice evapotranspiration module with SPAC(soil-plant-atmospheric-continuum), and the third is the groundwater and open channel flows based upon the interrehtionship module. The model simulates the hydrlogical processes of infiltration, soil water storage, deep perocolation or echarge to the shallow water table, transpiration and evaporation from the soil surface and also the interrelationship of the groundwater and river flow exchange. To verify the applicability of the developed model, it was applied to the Kimjae Plains, located in the center of the Dongjin river basin in Korea, during the most serious drought season of 1994. The result shows that the estimated water net requirement was 757mm and the water deficit was about 5.9% in this area in 1994. This model can easily evaluate the irrigated water quantity and visualize the common crop demands and soil moisture conditions.

• Tunnel and Underground Space
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• v.14 no.3
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• pp.229-240
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• 2004

Coastal aquifers may serve as major sources fur freshwater. In many coastal aquifers, intrusion of seawater has become one of the major constraints imposed on groundwater utilization. The management of groundwater in coastal acquifers means making decision as to the pumping rate and the spatial distribution of wells. Several numerical techniques for flow and solute transport simulation can provide the means to achieve this goal. As a basic study to predict the intrusion of seawater in coastal phreatic aquifers, the coupled flow and solute transport analysis was conducted by use of the 3-D finite element code, SWICHA. In order to understand how the location and the shape of freshwater-seawater transition zone were affected by the boundary conditions and hydrogeologic variables, parametric study was carried out.