• Structural Engineering and Mechanics
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• v.30 no.3
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• pp.331-350
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• 2008

A framework for multi-platform analytical and multi-component hybrid (testing-analysis) simulations is described in this paper and illustrated with several application examples. The framework allows the integration of various analytical platforms and geographically distributed experimental facilities into a comprehensive pseudo-dynamic hybrid simulation. The object-oriented architecture of the framework enables easy inclusion of new analysis platforms or experimental models, and the addition of a multitude of auxiliary components, such as data acquisition and camera control. Four application examples are given, namely; (i) multi-platform analysis of a bridge with soil and structural models, (ii) multiplatform, multi-resolution analysis of a high-rise building, (iii) three-site small scale frame hybrid simulation, and (iv) three-site large scale bridge hybrid simulation. These simulations serve as illustrative examples of collaborative research among geographically distributed researchers employing different analysis platforms and testing equipment. The versatility of the framework, ease of including additional modules and the wide application potential demonstrated in the paper provide a rich research environment for structural and geotechnical engineering.

• Hwankyungkyoyuk
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• v.24 no.1
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• pp.40-48
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• 2011

SimRiver, computer simulation software for assessment of river water quality is an educational simulation software created for studying the relationship between human activity and river environment using epilithic diatom communities, The SimRiver program was applied to total seventy eight teachers of elementary, middle and high schools in Korea, and the teachers' reactions were analyzed with the questionnaire survey. Total 79.2% of the teachers estimated the possibility of SimRiver to be applied as a educational material in lessons is high. Especially total 93.6% of the teachers answered that they will use SimRiver in their lessons. The results of the questionnaire survey indicate that SimRiver is an interesting and easy simulator of alternative field exercise for students to understand the relationship between human activity and quality of river water.

• Environmental Engineering Research
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• v.23 no.4
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• pp.397-405
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• 2018

As regulations governing the control of volatile organic compounds (VOCs) have become increasingly stringent in China, regenerative thermal oxidizers (RTOs) have been more frequently applied in medium- and high-concentration VOCs treatments. However, due to the lack of existing RTO-related research, experience remains a dominant factor for industrial application. This paper thus aimed to establish a model for industrial RTOs, using a transient simulation method and thermal equilibrium model to simulate the internal velocities and temperature distributions of an RTO across multiple cycles. A comparison showed an error of less than 5% between most correlating simulated and experimental measurement points, verifying that the simulation method was accurate. After verification, the velocity and temperature fields inside the RTO were simulated to study the uniformity of temperature and velocity within the packed beds: both fields displayed high uniformity after gas flowed through the honeycomb regenerator. The effects of air volume, VOCs concentrations, and valve switching times on the oxidation chamber temperature, RTO outlet temperature, and thermal efficiency (as well as their averages) were studied. The VOCs removal rate in this study was constantly above 98%, and the average thermal efficiency reached 90%.

• Journal of Environmental Impact Assessment
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• v.16 no.4
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• pp.267-275
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• 2007

In this study, relationship between the air pollution of Siheung city and the relative contribution of automobiles to the city's pollution was evaluated for the first time. Then, new air pollution exposure index was developed through simulation. Using the newly developed index, two different urban development scenarios were compared to present a sustainable urban development plan to reduce air pollution from the land utilization point of view. According to the result of this simulation, air quality of the city was found to be affected significantly by human activities. More populated area showed worse level of air quality. Any development in the city resulted in more automobile activity and deterioration of air quality. This simulation result thus explains that a rapid increase of automobiles accompanied by the land development near local roadsides in the city is the major cause of air pollution in Siheung city. In this study, if urban activities are vigorous in an area with high air pollution, people are more likely to be exposed to air pollutant under the bad environmental conditions. On the other hand, if urban activities are less vigorous in an area with high pollution or if urban activities are vigorous in an area with less pollution, the environmental condition was positive. The APEI (Air Pollution Exposure Index) was developed based on these considerations. Scenarios 1 and 2 were compared and analyzed using APEI. In result, scenario 1 is the case in which land is developed and used in an environmentally favorable manner. From this study, it was proved that the impact of air pollution on human health can be minimized with proper land use. The result form the current study can be used as the basic information to solve problems from improper land utilization and air pollution (by road traffic). It also can be utilized to evaluate air pollution level according to land use and road characteristics and to help to choose the best location of land use to comply with the road function and status.

• Journal of Environmental Science International
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• v.20 no.9
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• pp.1151-1163
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• 2011

The bed change analysis near the opening gate of a dam or weir to release deposited sediments have been conducted mostly using the numerical models. However, the use of unverified input parameters in the numerical model is able to produce the different results with natural and real conditions. Also, the bed changes near the opening gate of a dam or weir calculated with a numerical model could be varied depending on the geometry extent included the downstream area with supercritical flow in the model. In addition, the different time steps could provide different results in the bed change calculation, even though other conditions such as input parameters, geometries, and total simulation time were same. Therefore, in this study, hydraulic experiments were performed to validate the eddy viscosity coefficient which is the one of important input parameters in the RMA2 model and relevant to variation of simulation results. The bed changes were calculated using the SED2D model based on flow results calculated in the RMA2 model with the verified and selected eddy viscosity coefficient and also compared with experimental results. The bed changes near the opening gate were underestimated in the numerical model comparing with experimental results except only the numerical case without the modeling section of sediment release pipe and downstream area where the supercritical flow was produced. For the simulation of minimum time steps, different shapes of scour hole were produced in numerical and physical modeling.

• Journal of the Korean earth science society
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• v.24 no.5
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• pp.411-419
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• 2003

The assessment of environmental impact on NO$_2$ (or TSP) emitted by vehicles is important for local residents from the point of view of their health and environmental protection. In the course of field investigations, correct concentrations are measured and meteorological data are observed for numerical simulation. To determine background concentration for numerical simulation, annual average concentrations of NO$_2$ (or TSP) are estimated using the Puff-Plume model. If the estimated result affects the environment, it must be considered in the environmental conservation activity. To make the process of a estimation of environmental assessment more easily, this system is developed. Moreover, this system was supplied a Graphic User Interface (GH) for the user who calculated the concentration of air pollution exhausted from the traffic on general roads except special roads such as interchanges and entrances to tunnels. This system can offer not only the numerical result but also a graphic display. Even a beginner who is not a professional programmer can calculate the result easily.

• Journal of Korea Water Resources Association
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• v.43 no.12
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• pp.1075-1082
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• 2010

The most effective and economic way for the mitigation planing against tsunami disasters is to develop an emergency action plan along the coastline vulnerable to unexpected tsunami attacks. The plan should be developed based on the historical tsunami events and the projected scenarios. In this study, an evacuation simulation is made based on the projected scenarios at Imwon Port as a part of the emergency action plan. The produced simulation could be used by the authorized organizations in a disaster training against tsunami attacks.

• Journal of the Korean earth science society
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• v.31 no.5
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• pp.437-447
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• 2010

Spatial estimation of environmental variables has been regarded as an important preliminary procedure for decision-making. A minimum variance criterion, which has often been adopted in traditional kriging algorithms, does not always guarantee the optimal estimates for subsequent decision-making processes. In this paper, a geostatistical framework is illustrated that consists of uncertainty modeling via stochastic simulation and risk modeling based on loss functions for the selection of optimal estimates. Loss functions that quantify the impact of choosing any estimate different from the unknown true value are linked to geostatistical simulation. A hybrid loss function is especially presented to account for the different impact of over- and underestimation of different land-use types. The loss function-specific estimates that minimize the expected loss are chosen as optimal estimates. The applicability of the geostatistical framework is demonstrated and discussed through a case study of copper mapping.

• Environmental Engineering Research
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• v.21 no.4
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• pp.355-364
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• 2016

Beijing, as a cradle of modern industry and the third largest metropolitan area in China, faces more responsibilities to adjust industrial structure and mitigate carbon emissions. The purpose of this study is aimed at predicting and comparing industrial carbon emissions of Beijing in ten scenarios under different policy focus, and then providing emission-cutting recommendations. In views of various scenarios issues, system dynamics has been applied to predict and simulate. To begin with, the model has been established following the step of causal loop diagram and stock flow diagram. This paper decomposes scenarios factors into energy structure, high energy consumption enterprises and growth rate of industrial output. The prediction and scenario simulation results shows that energy structure, carbon intensity and heavy energy consumption enterprises are key factors, and multiple factors has more significant impact on industrial carbon emissions. Hence, some recommendations about low-carbon mode of Beijing industrial carbon emission have been proposed according to simulation results.

• Journal of Astronomy and Space Sciences
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• v.16 no.2
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• pp.177-190
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• 1999

An absorbed heat-flux method for ground simulation of on-orbit thermal environment of satellite is addressed in this paper. For satellite ground test, high vacuum and extremely low temperature of deep space are achieved by space simulation chamber, while spatial environmental heating is simulated by employing the absorbed heat-flux method. The methodology is explained in detail with test requirement and setup implemented on a satellite. Developed heat-load control system is presented with an adjusted PID-control logic and the system schematic realized is shown. A practical and successful application of the heat simulation method to KOMPSAT(Korea Multi-purpose Satellite)thermal environmental test is demonstrated, finally.