• Journal of the Korea Society for Simulation
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• v.24 no.4
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• pp.23-28
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• 2015

The detection field is an important sector of the factors influencing the battle field. Basically, The radar emits a radio wave to perform the detection in the existing way. However, When most existing radars identify target by signal processing to return radio wave, Environmental attenuation factor does not reflected. The radar using this radio wave has got the possibility changing detect result depending on attenuation factor by environmental conditions, The operational problems may arise in a real battle field. Therefore, In this paper, When emitted radio waves were come back, Reflecting the environmental attenuation factor, Experimental attempts to identify the target to enable more accurately.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.841-847
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• 2011

In this study, a method to determine the design capacities of nonpoint source (NPS) pollutant treatment facilities in urban areas was suggested. A facility capacity to treat 80 percent of total SS discharge was estimated by 2-year rainfall - runoff - build-up and wash-off simulation at Goonja drainage district in Seoul. For wash-off simulation, four wash-off models (EMC, RC, EXP, and Joo model) were used. As the results, 80 percent of total SS discharge could be treated with only 7.7~31.4% facility capacity of peak flow. The suggested method and results will provide a guideline to determine design capacities of NPS pollutant treatment facility in urban areas.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.409-431
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• 2014

In this study, the characteristics in the simulation of high-resolution coastal weather, i.e. sea surface wind (SSW) and significant wave height (SWH), were studied in a southeastern coastal region of Korea using the WRF and SWAN models. This analyses was performed based on the effects of various input factors in the WRF and SWAN model during M-Case (moderate days with average 1.8 m SWH and $8.4ms^{-1}$ SSW) and R-Case (rough days with average 3.4 m SWH and $13.0ms^{-1}$ SSW) according to the strength of SSW and SWH. The effects of topography (TP), land cover (LC), and sea surface temperature (SST) for the simulation of SSW with the WRF model were somewhat high on v-component winds along the coastline and the adjacent sea of a more detailed grid simulation (333 m) during R-Case. The LC effect was apparent in all grid simulations during both cases regardless of the strength of SSW, whereas the TP effect had shown a difference (decrease or increase) of wind speed according to the strength of SSW (M-Case or R-Case). In addition, the effects of monthly mean currents (CR) and deepwater design waves (DW) for the simulation of SWH with the SWAN model predicted good agreement with observed SWH during R-Case compared to the M-Case. For example, the effects of CR and DW contributed to the increase of SWH during R-Case regardless of grid resolution, whereas the differences (decrease or increase) of SWH occurred according to each effect (CR or DW) during M-Case.

• Journal of Information Technology and Architecture
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• v.9 no.3
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• pp.253-263
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• 2012

Presented in the paper is a methodology for the distributed simulation of underwater warfare based on standard synthetic environment. In the case of underwater warfare simulation, it is very important to reflect environmental data, such as salinity and temperature. For the reusability and interoperability of environmental data, this paper adopts Synthetic Environmental Data Representation and Interchange Specification (SEDRIS(ISO standard for environmental data)). Although SEDRIS provides various merits as an international standard, applying of SEDRIS has been hindered by its broadness and heaviness. To relieve the difficulties, this paper proposes an efficient procedure to utilize SEDRIS technology for the atmosphere and underwater environment. This paper identifies SEDRIS structure for the atmosphere/underwater structured dimensional grid-based and implements the proposed procedure on the High Level Architecture (HLA) / Run-Time Infrastructure (RTI) to explain the generation of the battlefield in a distributed simulation system.

• Journal of Environmental Science International
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• v.29 no.1
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• pp.33-44
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• 2020

Recently, a variety of modeling studies have been conducted to examine the air quality over South Korea during the Korea - United States Air Quality (KORUS-AQ) campaign period (May 1 to June 10, 2016). This study investigates the impact of different meteorological initializations on atmospheric modeling results. We conduct several simulations during the KORUS-AQ period using the Weather Research and Forecasting (WRF) model with two different initial datasets, which is FNL of NCEP and ERA5 of ECMWF. Comparing the raw initial data, ERA5 showed better accuracy in the temperature, wind speed, and mixing ratio fields than those of NCEP-FNL. On the other hand, the results of WRF simulations with ERA5 showed better accuracy in the simulated temperature and mixing ratio than those with FNL, except for wind speed. Comparing the nudging efficiency of temperature and wind speed fields, the grid nudging effect on the FNL simulation was larger than that on the ERA5 simulation, but the results of mixing ratio field was the opposite. Overall, WRF simulation with ERA5 data showed a better performance for temperature and mixing ratio simulations than that with FNL data. For wind speed simulation, however, WRF simulation with FNL data indicated more accurate results compared to that with ERA5 data.

• Journal of Environmental Science International
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• v.18 no.8
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• pp.847-855
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• 2009

As a part of effort to establish an offshore wind resource assessment system of the Korean Peninsula, a numeric wind simulation using mesoscale climate model MM5 and a spatial distribution of offshore wind extracted from SAR remote-sensing satellite image is compared and analyzed. According to the analyzed results, the numeric wind simulation is found to have wind speed over predication tendency at the coastal sea area. Therefore, it is determined that a high-resolution wind simulation is required for complicated coastal landforms. The two methods are verified as useful ways to identify the spatial distribution of offshore wind by mutual complementation and if the meteor-statistical comparative analysis is performed in the future using adequate number of satellite images, it is expected to derive a general methodology enabling systematic validation and correction of the numeric wind simulation.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.299-312
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• 2016

The main objective of this paper is to develop computer simulation program for performance evaluation and cost estimation of a reverse osmosis (RO) and pressure-retarded osmosis (PRO) hybrid process to propose guidelines for its economic competitiveness use in the field. A solution-diffusion model modified with film theory and a simple cost model was applied to the simulation program. Using the simulation program, the effects of various factors, including the Operating conditions, membrane properties, and cost parameters on the RO and RO-PRO hybrid process performance and cost were examined. The simulation results showed that the RO-PRO hybrid process can be economically competitive with the RO process when electricity cost is more than 0.2 $/kWh, the PRO membrane cost is same as RO membrane cost, the power density is more than $8W/m^2$ and PRO recovery is same as 1/(1-RO recovery).

• Journal of Environmental Science International
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• v.29 no.1
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• pp.45-54
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• 2020

High-resolution meteorological simulations were conducted using a Weather Research and Forecasting (WRF) model with an Urban Canopy Model (UCM) in the Ulsan Metropolitan Region (UMR) where large-scale industrial facilities are located on the coast. We improved the land cover input data for the WRF-UCM by reclassifying the default urban category into four detailed areas (low and high-density residential areas, commercial areas, and industrial areas) using subdivided data (class 3) of the Environmental and Geographical Information System (EGIS). The urban area accounted for about 12% of the total UMR and the largest proportion (47.4%) was in the industrial area. Results from the WRF-UCM simulation in a summer episode with high temperatures showed that the modeled temperatures agreed greatly with the observations. Comparison with a standard WRF simulation (WRF-BASE) indicated that the temporal and spatial variations in surface air temperature in the UMR were properly captured. Specifically, the WRF-UCM reproduced daily maximum and nighttime variations in air temperature very well, indicating that our model can improve the accuracy of temperature simulation for a summer heatwave. However, the WRF-UCM somewhat overestimated wind speed in the UMR largely due to an increased air temperature gradient between land and sea.

• Journal of Environmental Impact Assessment
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• v.23 no.3
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• pp.177-186
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• 2014

Depending on the change of lifestyle and the improvement of people's living standards and rapid industrialization, urbanization of recent, demand for water is increasing rapidly. So emissions of domestic wastewater and various industrial waste water has increased, and water quality is worsening day by day. Therefore, in order to provide a measure against the occurrence of water pollution accident, this study was tried to simulate water pollution accident. This study simulated 2008 Gimcheon phenol accident using 1,2-D model, and analyze scenario for prevent of water pollution accident. Consequently the developed 1-D model presents high reappearance when compared with 2-D model, and has been able to obtain results in a short simulation run time. This study will contribute to the water pollution incident response prediction system and water quality analysis in the future.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.4
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• pp.253-259
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• 2018

Structure behaviors resulting from an earthquake are experimentally simulated mainly through a shaking table test. As for large-scale structures, however, size effects over a miniature may make it difficult to assess actual behaviors properly. To address this problem, research on the hybrid simulation is being conducted actively. This method is to implement numerical analysis on framework members that affect the general behavior of the structure dominantly through an actual scale experiment and on the rest parts by applying the substructuring technique. However, existing studies on hybrid simulation focus mainly on Slow experimental methods, which are disadvantageous in that it is unable to assess behaviors close to the actual level if material properties change depending on the speed or the influence of inertial force is significant. The present study aims to establish a Real-time hybrid simulation system capable of excitation based on the actual time history and to verify its performance and applicability. The hybrid simulation system built up in this study utilizes the ATS Compensator system, CR integrator, etc. in order to make the target displacement the same with the measured displacement on the basis of MATLAB/Simulink. The target structure was a 2-span bridge and an RC pier to support it was produced as an experimental model in order for the shaking table test and Slow and Real-time hybrid simulations. Behaviors that result from the earthquake of El Centro were examined, and the results were analyzed comparatively. In comparison with the results of the shaking table test, the Real-time hybrid simulation produced more similar maximum displacement and vibration behaviors than the Slow hybrid simulation. Hence, it is thought that the Real-time hybrid simulation proposed in this study can be utilized usefully in seismic capacity assessment of structural systems such as RC pier that are highly non-linear and time-dependent.