• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.3 no.3
• /
• pp.37-44
• /
• 2000

The objective of this study is on suggesting the simulation model of 10 selected plants for the traffic noise barrier through field experiment by computer. The field experiment was carried out at the traffic noise barrier of Honam highway. The results are as follows. 1. It was identified that Paederia scandens, Celastrus Orbiculatus, Lonicera japonica, Wisteria floribunda, Parthenocissus tricuspidata and Parthenocissus quinquefolia grows well vertically and takes 3 years in covering completely. 2. It was identified that Trachelospermum asiaticum and Hedera rhombea, evergreen Climber(vine), grows slowly in comparative with other deciduous Climbers(vine), but give drivers good landscapes in winter. So those have considerable value in the south region of Taejeon. 3. It was identified that Wisteria jl.oribunda, Lonicera japonica, Paederia scandens, Clematis mandschurica and Campsis grandijlora showed good view in flowering period. 4. It was identified that auxiliary materials for inducing growth were needed in other plants except Parthenocissus tricuspidata, Parthenocissus quinquefolia. 5. It was identified that subsequent research about the auxiliary materials for inducing growth and adequate planting distance of each plants is needed for actual application.

• Journal of Korean Society on Water Environment
• /
• v.25 no.3
• /
• pp.375-385
• /
• 2009

The estimation of delivery ratio is a essential part of Korean Total Maximum Daily Loads (TMDL) procedure which needs a number of observed stream flow and pollutants data. If observed data were not sufficient, researchers have to find other alternatives. One of them is to make indirect data by using watershed models, such as Soil and Water Assessment Tool (SWAT) and Hydrological Simulation Program - FORTRAN (HSPF) and so on. In this study, indirect daily data was made by using SWAT model. To build the Byongseong-SWAT model accurately, crop cultures are reflected by handling the MGT.file in SWAT model. Especially, mass of manure and schedule of crop culture are inputted through investigating domestic research papers as well as fieldwork. After calibrating SWAT model in comparison with the 22-years flow and pollutants observed outlet data, the delivery ratio of Byongseong watershed is calculated by using daily simulated data during 2004-2007. Empirical equations for delivery ratio through multi-regression analysis are developed by using meteorological and physical factors such as flow, watershed area, stream length, catchment slope, curve number (CN) and subbasin's pollutant discharge loads.

• Journal of Korean Society on Water Environment
• /
• v.23 no.6
• /
• pp.973-984
• /
• 2007

This study developed and calculated alternative evaluation index (AEI) from the effectiveness analyses of alternatives for rehabilitation of distorted hydrologic cycle. The feasible alternatives for the poor-conditioned region in the Anyangcheon watershed were proposed and quantitatively analyzed using continuous water quantity/quality simulation model, Hydrological Simulation Program-Fortran (HSPF). The effectiveness analyses include 355th flow and 275th flow of flow duration curve and number of increased days to satisfy the target monthly flow for water quantity and BOD average concentration, total daily loads and number of increased days to satisfy the target concentration and total daily loads. The feasible alternatives are restoration of covered stream, prevention of streamflow loss through sewers, redevelopment of existing reservoir, reuse of treated wastewater, use of groundwater collected by subway stations and construction of small wastewater treatment plant. Therefore, alternative priority ranking was derived from AEIs. It will be effective to make an integrated watershed management for sustainable development.

• Earthquakes and Structures
• /
• v.17 no.4
• /
• pp.337-354
• /
• 2019

This paper presents the results of experimental and numerical studies conducted to investigate the behavior of exterior reinforced concrete beam column joints (BCJ) strengthened by using carbon fiber reinforced polymer (CFRP) sheets. Twelve reinforced concrete beam-column joints (BCJ) were tested in an experimental program by simulating the joints in seismically deficient old buildings. One group of BCJs was designed to fail in flexure at the BCJ interface, and the second group was designed to ensure joint shear failure. One specimen in each set was -retrofitted with CFRP sheet wrapped diagonally around the joint. The specimens were subjected to both monotonic and cyclic loading up to failure. 3D finite element simulation of the BCJs tested in the experimental program was carried out using the software ABAQUS, adopting the damage plasticity model (CDP) for concrete. The experimental results showed that retrofitting of the shear deficient, BCJs by CFRP sheets enhanced the strength and ductility and the failure mode changed from shear failure in the joints to the desired flexural failure in the beam segment. The FE simulation of BCJs showed a good agreement with the experimental results, which indicated that the CDP model could be used to model the problems of the monotonic and cyclic loading of beam-column reinforced concrete joints.

• Wind and Structures
• /
• v.38 no.4
• /
• pp.245-259
• /
• 2024

In a tornadic wind field, the vertical velocity component in certain regions of tornadoes can be significant, forming one of the major differences between tornadic wind fields and synoptic straight-line wind fields. To better understand the wind characteristics of tornadoes and properly estimate the action of tornadoes on civil structures, it is important to ensure that all the attributes of tornadoes are captured. Although Doppler radars have been used to measure tornadic wind fields, they can only directly provide information on quasi-horizontal velocity. Therefore, lots of numerical simulations and experimental tests in previous research ignored the vertical velocity at the boundary. However, the influence of vertical velocity in tornadic wind fields is not evaluated. To address this research gap, this study is to use an approach to derive the vertical velocity component based on the horizontal velocities extracted from the radar-measured data by mass continuity. This approach will be illustrated by using the radar-measured data of Spencer Tornado as an example. The vertical velocity component is included in the initial inflow condition in the CFD simulation to assess the influence of including vertical velocity in the initial inflow condition on the entire tornadic wind field.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.4
• /
• pp.232-238
• /
• 2012

In this study, the noise mapping simulation is executed to design an effective barrier reducing noise levels of a school site. The geographical features of the ambient site and the school buildings are modelled in detail in order to consider sound propagation, deflection, and absorption phenomena etc. The main sound source, sound power level of expressway, is estimated on the basis of measured noise levels at several points of the site. The noise mapping simulation is performed by using ENPro, environmental noise prediction program based on ISO 9613 to analysis the effectiveness of noise barrier. Consequently, the noise barrier is designed to meet an environmental noise standard and satisfy low cost and safety conditions.

• Environmental Engineering Research
• /
• v.14 no.4
• /
• pp.244-249
• /
• 2009

Designing an ozone contactor is complicated because the residual ozone, log C. parvum inactivation, and bromate formation should be optimized with fluctuating water quality. OCM software was developed to assist a plant designer or an operator to fulfill the sophisticated optimization required in the design or operation of a new or an existing plant. In this article, numerical simulations were carried out using the OCM software for the design of a new ozone contactor under diverse design factors (i.e., three pHs, three temperatures, low and high dispersion numbers, and four and ten cells with complete mixing) with kinetic parameters obtained from the sand-filter effluent of a water treatment plant treating water from the Paldang impoundment. The results of the simulation suggested that a high residual ozone concentration at low pH and low temperature would be challenging, and PFR-like hydrodynamics could lower the residual ozone concentration. The inactivation of C. parvum oocysts increased at a lower pH. A lower dispersion number and more cell division increased the inactivation efficiency. Bromate was instantaneously formed during the initial ozonation stage. The effluent concentration was much lower than the regulatory levels imposed by the USEPA because of the low bromide level in raw water.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.365-368
• /
• 2006

RBSN Method, Rigid-Body-Spring Network Method, is a structural analysis method that overcomes the problems faced in FEM analysis of concrete or crack forming structures. In RBSN, irregular lattices are used to model structural components consisting of bulk material, curvilinear reinforcements, and their interfaces. Because reinforcements and their interfaces in the bulk material are freely positioned, meshing is irrespective of the geometry of the representing bulk material. In this paper, RBSN method of 3D is applied in simulating the pull-out test of FRP (Fiber Reinforced Polymer) embedded in concrete. The comparison of analysis results to experimental results shows that RBSN method simulates the shear-slip behavior very precisely. From the analysis results, 3D RBSN method is proven to be an effective and accurate analysis method for concrete structural analysis. Also, the results show that RBSN method can be a potential analysis method for concrete structures that can replace the current FEM analysis.

• Journal of Environmental Impact Assessment
• /
• v.21 no.1
• /
• pp.105-117
• /
• 2012

Future climate according to land-use change was simulated by regional climate model. The goal of study was to predict the distribution of meteorological elements using the Weather Research & Forecasting Model (WRF). The KME (Korea Ministry of Environment) medium-category land-use classification was used as dominant vegetation types. Meteorological modeling requires higher and more sophisticated land-use and initialization data. The WRF model simulations with HyTAG land-use indicated certain change in potential vegetation distribution in the future (2086-2088). Compared to the past (1986-1988) distribution, coniferous forest area was decreased in metropolitan and areas with complex terrain. The research shows a possibility to simulate regional climate with high resolution. As a result, the future climate was predicted to $4.5^{\circ}$ which was $0.5^{\circ}$ higher than prediction by Meteorological Administration. To improve future prediction of regional area, regional climate model with HyTAG as well as high resolution initial values such as urban growth and CO2 flux simulation would be desirable.

• Geomechanics and Engineering
• /
• v.24 no.2
• /
• pp.167-178
• /
• 2021

Spatial variability is an inherent uncertainty of soil properties. Current reliability analyses generally incorporate random field theory and Monte Carlo simulation (MCS) when dealing with spatial variability, in which the computational efficiency is a significant challenge. This paper proposes a KL-FORM algorithm to improve the computational efficiency. In the proposed KL-FORM, Karhunen-Loeve (KL) expansion is used for discretizing random fields, and first-order reliability method (FORM) is employed for reliability analysis. The KL expansion and FORM can be used in conjunction, through adopting independent standard normal variables in the discretization of KL expansion as the basic variables in the FORM. To illustrate the effectiveness of this KL-FORM, it is applied to a case study of a strip footing in spatially variable unsaturated soil under rainfall, in which the bearing capacity of the footing is computed by numerical simulation. This case study shows that the KL-FORM is accurate and efficient. The parametric analyses suggest that ignoring the spatial variability of the soil may lead to an underestimation of the reliability index of the footing.