• 한국태양에너지학회 논문집
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• 제39권3호
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• pp.29-45
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• 2019

As the solar energy market grows, the need to investigate the potential of photovoltaic system is being highlighted. However, due to the lack of plain field, the system on top of buildings is being exploited. This paper analyzes the potential to install PV systems on the rooftops. First of all, with the aid of a photovoltaic system simulation software, buildings were designed in a specific area based on the architectural data. And then, with the same software, the potential to install photovoltaic system was explored by placing PV modules on the buildings' rooftops. The installation potential was calculated and simulated with consideration for obstacles on the rooftops. The parameters are composed of available area for system installation, area utilization rate, PV system power capacity, operation yield hour per day and performance ratio. In the simulation, 5 sites were analyzed based on their architectural data. In the end, reliable data that can be utilized were collected for the potential to install the system with the photovoltaic system simulation software.

• Genomics & Informatics
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• 제20권1호
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• pp.8.1-8.14
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• 2022

Despite the success of recent genome-wide association studies investigating longitudinal traits, a large fraction of overall heritability remains unexplained. This suggests that some of the missing heritability may be accounted for by gene-gene and gene-time/environment interactions. In this paper, we develop a Bayesian variable selection method for longitudinal genetic data based on mixed models. The method jointly models the main effects and interactions of all candidate genetic variants and non-genetic factors and has higher statistical power than previous approaches. To account for the within-subject dependence structure, we propose a grid-based approach that models only one fixed-dimensional covariance matrix, which is thus applicable to data where subjects have different numbers of time points. We provide the theoretical basis of our Bayesian method and then illustrate its performance using data from the 1000 Genome Project with various simulation settings. Several simulation studies show that our multivariate method increases the statistical power compared to the corresponding univariate method and can detect gene-time/ environment interactions well. We further evaluate our method with different numbers of individuals, variants, and causal variants, as well as different trait-heritability, and conclude that our method performs reasonably well with various simulation settings.

• 한국환경과학회지
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• 제33권7호
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• pp.443-452
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• 2024

The recent increase in impermeable surfaces due to urbanization and the occurrence of concentrated heavy rainfall events caused by climate change have led to an increase in urban flooding. To predict and prepare for flood damage, a convenient and highly accurate simulation of rainfall-runoff based on geospatial information is essential. In this study, the storm water management model (SWMM) was applied to simulate rainfall runoff in the Bangbae-dong area of Seoul, using two sets of topographical data: The conventional topographic digital elevation model (TOPO-DEM) and the proposed shuttle radar topography mission (SRTM)-DEM. To evaluate the applicability of the SRTM-DEM for rainfall-runoff modeling, two DEMs were constructed for the study area, and rainfall-runoff simulations were performed. The construction of the terrain data for the study area generally reflected the topographical characteristics of the area. Quantitative evaluation of the rainfall-runoff simulation results indicated that the outcomes were similar to those obtained using the existing TOPO-DEM. Based on the results of this study, we propose the use of SRTM-DEM, a more convenient terrain data, in rainfall-runoff studies, rather than asserting the superiority of a specific geospatial data.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 추계학술논문발표회 논문집
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• pp.444-449
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• 2008

Fire model shall be verified and validated to reliably predict the consequences of fires within its limitations. This study aims to predict pool fire phenomena with two rooms using CFAST and to compare CFAST simulation results with PRISME experimental data which can be applicable to the fire of nuclear power plant facility. Five different mass loss rate(MLR) are used in the simulation and the simulated results of specific quantities such as temperature, chemical composition are compared to the experimental data. From this study, the CFAST simulation results with the proper MLR show better similarity and trend with pool fire experimental data.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권1호
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• pp.37-50
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• 2016

A large eddy simulation (LES) of a turbulent channel flow is performed by using the third order low-storage Runge-Kutta method in time and second order finite difference formulation in space with staggered grid at a Reynolds number, $Re_{\tau}=590$ based on the channel half width, ${\delta}$ and wall shear velocity, $u_{\tau}$. To reduce the calculation cost of LES, algebraic wall model (AWM) is applied to approximate the near-wall region. The computation is performed in a domain of $2{\pi}{\delta}{\times}2{\delta}{\times}{\pi}{\delta}$ with $32{\times}20{\times}32$ grid points. Standard Smagorinsky model is used for subgrid-scale (SGS) modeling. Essential turbulence statistics of the flow field are computed and compared with Direct Numerical Simulation (DNS) data and LES data using no wall model. Agreements as well as discrepancies are discussed. The flow structures in the computed flow field have also been discussed and compared with LES data using no wall model.

• 한국시뮬레이션학회논문지
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• 제5권2호
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• pp.25-40
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• 1996

Modeling of systems for intensive knowledge-based processing requires a modeling methodology that makes efficient access to the information in huge data base models. The proposed level access mothodology is a modeling approach applicable to systems where data is stored in a hierarchical and modular modules of active memory cells(processor/memory pairs). It significantly reduces the effort required to create discrete event simulation models constructed in hierarchical, modular fashion for above application. Level access mothodology achieves parallel access to models within the modular, hierarchical modules(clusters) by broadcasting the desired operations(e.g. querying information, storing data and so on) to all the cells below a certain desired hierarchical level. Level access methodology exploits the capabilities of object-oriented programming to provide a flexible communication paradigm that combines port-to-port coupling with name-directed massaging. Several examples are given to illustrate the utility of the methodology.

• 한국유체기계학회 논문집
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• 제9권6호
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• pp.22-28
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• 2006

Operation of a microturbine was simulated on the basis of component characteristic parameters obtained from performance test. Characteristic parameters, such as compressor and turbine efficiencies, recuperator effectiveness as well as turbine inlet temperature, were obtained for a wide operation range. Component characteristics including performance maps and characteristic curves were generated using measured data. Based on the component characteristics, a simulation program was constructed and operation of the microturbine was simulated, and the simulated results were compared with the measured data to verify the program. Also, influence of variation in the power control scheme on the operating characteristic and performance of the engine was simulated. The simulation program can be used for predicting operation of both healthy and degraded engine conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.113-115
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• 2000

So far, it was very difficult to simulate the dispersed generation system including PV generation system using EMTP or EMTDC because the source of the dispersed generation system has a particular VI characteristic equation. In this paper, a novel simulation method of PV generation system has proposed and a new solar cell component for EMTDC is also developed. The VI characteristic equation of solar cell is used in order to realize the solar generation system in EMTDC simulation. Consequently the simulation of PV power generation system using field data is realized and acceptable results, which show close match between the real data of PV panel and the simulated data, were obtained.

• 한국국방경영분석학회지
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• 제22권1호
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• pp.142-155
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• 1996

In this research, our objective is to develop a model which could evaluate the maintenance capability for a maintenance battalion in the mechanized division. To analyze the maintenance system, we obtained various data related to maintenance capability and described the maintenance process as a network type. This network type model is then translated to SLAM-II network model to simulate the system. The simulation model can be operated by using appropriate input data and simulation results are obtained. The simulation model can be applied in various way. Through the simulation we could find the bottle neck point in the maintenance process. Also the maximum capability of maintenance with on hand asset and the wartime supportability can be evaluated. The mode provides sensitivity analysis by changing various imput data such as the number of repairmen, repair time, failure rate and so on.

• 한국분무공학회지
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• 제18권1호
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• pp.61-65
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• 2013

In case of GDI engine, shape of injected fuel and injection mass are one of the most important factors for good fuel efficiency and power. But it should be too inefficient and difficult to acquire injection mass data by experiment because condition in engine vary with temperature, pressure, and so on. So, this paper suggests the AMESim (Advanced Modeling Environment for Simulation of Engineering Systems) as simulation program to calculate injection mass. For both simulation and experiment, n-heptane is used as fuel. In AMESim, I modeled the GDI injector and simulated several cases. In experiment, I acquired the injection mass using Bosch method to apply ambient pressure. The AMESim show reasonable result in comparison with experimental data especially at injection pressure 15 MPa. Other conditions are also in good accord with experimental data but error is a little bit large because the injection mass is so low.