• Journal of the Korean GEO-environmental Society
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• v.7 no.1
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• pp.67-80
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• 2006

This paper presented an application of the geotechnical hybrid-online simulation to the consolidation settlement problem of soft clay. Conventional numerical analyses have used idealized soil constitutive models obtained from the laboratory soil tests. On the other hand, in the hybrid-online simulation, soil response was directly introduced to numerical analyses from the soil element test, and, therefore, the complicated parameter estimation was not required in this method. Fundamentals of the hybrid-online simulation method and the development of the algorithm and corresponding hardware and software for the system were presented in this study. Furthermore, an incremental loading consolidation and the hydraulic conductivity test and a comparative study using the Terzagh's conventional consolidation theory were carried out for the system verification including the performance of the experimental device and source coding of software components, and the data reliability obtained from the system. In conclusion, we found that the hybrid-online consolidation simulation system could reproduce the consolidation behavior of the remolded Kaolinite specimen withoutany discrepancies.

• Journal of Environmental Science International
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• v.9 no.5
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• pp.375-384
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• 2000

It is very important to interprete and simulate the variation of phytoplankton maximum region for the prediction and control of red tide. This study was composed of two parts first the hydrodynamic simulation such as residual current and salinity diffusion and second the ecological simulation such as phytoplankton distribution according to freshwater discharge and pollutant loads. Without the Nakdong river discharge residual current was stagnated in inner side of this estuary and surface distribution of salinity was over 25psu. On the contrary with summer mean discharge freshwater stretched very far outward and some waters flowed into Chinhae Bay through the Kadok channel and low salinity extended over coastal sea and salinity front occurred. From the result of contributed physical process to phytioplankton biomass the accumulation was occurred at the west part of this estuary and the Kadok channel with the Nakdong river discharge. When more increased input discharge the accumulation band was transported to outer side of this estuary. The frequently outbreak of red tide in this area is caused by accumulation of physical processes. The phytoplankton maximum region located inner side of this estuary without the Nakdong river discharge and with mean discharge of winter but it was moved to outer side when mean discharge of the Nakdong river was increased. The variation of input concentration from the land loads was not largely influenced on phytoplankton biomass and location of maximum region. When discharge was increased phytoplankton maximum region was transferred to inner side of the Kadok channel. ON the other hand when discharge was decreased phytoplankton maximum region was transferred to inner side of this estuary and chlorophyll a contents increased to over 20$\mu\textrm{g}$/L Therefore if any other conditions are favorable for growth of phytoplankton. decreas of discharge causes to increase of possibility of red tide outbreak.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.1035-1043
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• 2009

High turbid water in the River has been one of the major concerns to the downstream residence. Especially in the Nakdong River basin severe turbid water problem occurred in year 2002 and 2003 due to the typhoon Rusa and Maemi consecutively. The main objective of this study is to develop turbid water management system in reservoir downstream of the Nakdong River combining physically based semi-distributed hydrologic simulation model SWAT with 1-dimensional dynamic water quality simulation model. SWAT model covers the area from the upstream of the Imha and Andong reservoir to the Gumi gage station for the purpose of estimating flow rates and suspended sediment of the tributaries. From year 1999 to 2007 runoff simulation for 8 years $R_{eff}$ and $R^2$ ranges $0.46{\sim}0.9$, $0.54{\sim}0.99$ respectively. Through the linkage of models, outputs of SWAT model such as suspended sediment and flow rates of the tributaries can be incorporated into the 1-dimensional dynamic water quality simulation model, KoRiv1 to support joint reservoir operation considering the turbidity released from Imha and Andong reservoir. The applicability of model simulation has been tested for year 2006 and compared with measured data.

• Atmosphere
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• v.18 no.4
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• pp.339-354
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• 2008

A numerical simulation of a heavy snowfall event that occurred 13 January 2008 along the Yeongdong coastal area, was performed using WRF (Weather Research and Forecasting) in order to reveal mesoscale structures and to construct a conceptual model showing the meteorological background that caused the large difference in snowfall amounts between the Yeongdong mountain area and the Yeongdong coastal area. The simulation results matched well with various observations such as corresponding 12h-accumulated observed precipitation, surface wind obscrvation, radar echoes, and satellite infrared images. The simulation and the observations showed that the scale of the event was of meso - $\beta$ and meso - $\gamma$ scale. The simulation represented well the mesoscale process causing the large difference in snowfall amounts in the two areas. First, wind flow was kept, to a certain extent, from crossing the mountains due to the blocking effect of the low Froude number (~1). The northeast flow over the adjaccnt sea tumcd northwest as it approachcd the mountains, where it was trapped, allowing so-called cold air damming. Second, a strong convergence area formed where the cold northwest flow along the Yeongdong coastal area and the relatively warm and moist northeast flow advecting toward the coast met, supporting the fonllation of a coastal front. Thus, the vertical motion was strongest over the front located near the coast, leading to the heavy snowfall there rather than in the remote mountain area.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.6
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• pp.827-841
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• 1999

The air quality simulation models in wide use for air quality impact assessmetns are reviewed. After an intensive survey and comparative study upon the environmental impact assessment reports submitted to Ministry of Environment during 1990~1998, we could identify the major common problems with the air quality impact assessment procedures. Several remedies are presented here, including use of the screening models applicable to the complex terrain.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2005.05a
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• pp.165-165
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• 2005

• KEPCO Journal on Electric Power and Energy
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• v.7 no.1
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• pp.145-152
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• 2021

Environmental change due to construction of large offshore wind farm has been a debate for a long time in Korea. There are various data acquired on hydrodynamics around this area before and during construction of offshore wind farm but no data during operation could be made due to delayed schedule. In this study, environmental change such as bathymetry change and scouring was forecasted using MIKE, numerical hydrodynamics model, and its results were validated using the observation data before and during construction.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.838-848
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• 2013

The Community Multiscale Air Quality (CMAQ) model is capable of providing high quality atmospheric chemistry profiles through the utilization of high-resolution meteorology and emissions data. However, it cannot simulate air quality accurately if input data are not appropriate and reliable. One of the most important inputs required by CMAQ is the air pollutants emissions, which determines air pollutants concentrations during the simulation. For the CMAQ simulation of Korean peninsula, we, in general, use the Korean National Emission Inventory data which are estimated by Clean Air Policy Support System (CAPSS). However, since they are not provided by model-ready emission data, we should convert CAPSS emissions into model-ready data. The SMOKE is the emission model we used in this study to generate CMAQ-ready emissions. Because processing the emissions data is very monotonous and tedious work, we have developed CAPSS2SMOKE program to convert CAPSS emissions into SMOKE-ready data with ease and effective. CAPSS2SMOKE program consists of many codes and routines such as source classification code, $PM_{10}$ to $PM_{2.5}$ ratio code, map projection conversion routine, spatial allocation routine, and so on. To verify the CAPSS2SMOKE program, we have run SMOKE using the CAPSS 2009 emissions and found that the SMOKE results inherits CAPSS emissions quite well.

• Asian Journal of Turfgrass Science
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• v.20 no.1
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• pp.93-105
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• 2006

The construction of golf courses has had adverse effects on the natural landscape and delicate ecosystem of Korea. Efficiency in planning and design was necessary to minimize the environmental impact of the original construction. However, the ordinal design methods have limited the data processing by the massive scale of the project of golf course development. Conventional design methods did not have a proper tool for alternative plans on pre-estimation of landscape destruction or minimizing of the environmental impact. Therefore, advanced computerized techniques need to be adapted for golf course design to solve the problems concerning the environmental impacts. Geographic information system (GIS) was applied on the process of geographical data input and analysis through the final outputs. Simulation works by the total database management enable the pre-investigation of the design In view of an assessment of environmental impacts. It is also possible to evaluate plans easily and propose the alternatives properly. Precise quantity calculation of engineering works by computer system should be guaranteed scientific, economic, and environmentally-sound.

• Environmental Analysis Health and Toxicology
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• v.10 no.1_2
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• pp.21-35
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• 1995

Risk assessment processes, which include processes for the estimation of human cancer potency using animal bioassay data and calculation of human exposure, entail uncertainties. In the exposure assessment process, exposure scenarios with various assumptions could affect the exposure amount and excess cancer risk. We compared risk estimates among various exposure scenarios of vinyl chloride, trichloroethylene and tetrachloroethylene in tap water. The contaminant concentrations were analyzed from tap water samples in Seoul from 1993 to 1994. The oral and inhalation cancer potencies of the contaminants were estimated using multistage, Weibull, lognormal, and Mantel-Bryan model in TOX-RISK computer software. In the first case, human excess cancer risk was estimated by the US EPA method used to set the MCL(maximum contaminant level). In the second and third case, the risk was estimated for multi-route exposure with and without adopting Monte-Carlo simulation, respectively. In the second case, exposure input parameters and cancer potencies used probability distributions, and in the third case, those values used point estimates(mean, and maximum or 95% upper-bound value). As a result, while the excess cancer risk estimated by US EPA method considering only direct ingestion tended to be underestimated, the risk which was estimated by considering multi-route exposure without Monte-Carlo simulation and then using the maximum or 95% upper-bound value as input parameters tended to be overestimated. In risk assessment for volatile organic compounds, considering multi-route exposure with adopting Monte-Carlo analysis seems to provide the most reasonable estimations.