• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.160.1-160.1
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• 2011

In this study, the influence of methodology of assessing water levels on the discharge coefficient of sluice for tidal power generation was investigated. A physical experiment was performed in a planar open channel by installing 1/70 scale model of the sluice caisson in the planar open channel. In front of and behind the sluice model, sloping bathymetry was made to reproduce corresponding field condition. By analyzing the experimental results, it was found that the location of measuring water levels significantly affects the estimates of the discharge coefficient, due to the variability of the parameter according to the head difference between the measuring locations. Therefore, it is necessary to be careful in estimating and utilizing the discharge coefficient in the relevant study of a tidal power generation.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.05a
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• pp.353-358
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• 2004

In recent, the trends in national energy Policy are established in the context of the integrated risk estimation for various national electricity generating options. The approach takes account of health, environmental, economic, and social aspects of electricity generation systems. In the present work, nuclear, coal, and LNG sources are chosen because these hold more than 90% of national total electricity generation in a descending order. A life cycle assessment (LCA) methodology is used for comparing environmental impacts of these options during the life cycle such as construction, operation as well as disposal stages. Here, the LCA consists of life cycle inventory analysis, classification/selection process of impact categories, characterization process, and normalization process of each category. LCA can be an useful tool for environmental impact assessment of future national energy options. At the planning stage of future energy Policies, the results of LCA would be taken into consideration. According to data update at the construction and disposal stages, the LCA needs to be conducted iteratively.

• Economic and Environmental Geology
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• v.33 no.4
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• pp.283-293
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• 2000

A set of geophysical survey results over an area in Bookil-myun, Chungwon-Gun, Chungcheongbuk-Do is presented; resistivity logging, d.c. sounding, dipole-dipole resistivity, and controlled-source magnetotelluric (CSMT) surveys. These surveys were chosen in this research for the estimation of the basement depth and the delineation of the hydrogeologic structure over the survey area. The results provide an optimal input to a hydrogeologic modeling analysis using the strategies built in GIS software. A total of 14 lines of dipole-dipole resistivity surveys, 25 stations of d.c. sounding and 6 stations of CSMT sounding were performed. In addition 10 boreholes were chosen for resistivity logging to correlate the logs to the surface data. A quantitative information on the hydrogeologic structure over the area is provided by synthesizing the results from various geophysical data and attribute layers are constructed by utilizing a GIS software Arc/ Info. The constructed layers match well to the hydrogeologic structures, which were outlined from the drilling data. The methodology tested and adopted in this study would be useful for providing a more reliable input to the hydrogeologic model setup.

• Geomechanics and Engineering
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• v.20 no.2
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• pp.121-129
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• 2020

In the design of geotechnical structures, engineers choose either peak or critical state friction angles. Unfortunately, this selection is based on engineer's preference for economy or safety and lacks the assessment of the expected level of deformation. To fill this gap in the design process, this study proposes a strain based empirical method. Proposed method is founded on the experimentally supported assumption that higher dilatancy angles result in more brittle soil response. Using numerous triaxial test data on ten different soils, an empirical design chart is developed that allows the estimation of shear strain at failure based on soil's peak dilatancy angle and mean grain diameter. Developed empirical chart is verified by conducting a small scale retaining wall physical model test. Finally, a design methodology is proposed that makes the selection of design friction angle in structured way possible based on the serviceability limits of the proposed structure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.31-38
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• 1998

In this study, statistical analyses implemented in the EPRI EQHAZARD programs were employed to estimate the sismicity parameters in the Korean peninsula based upon an combined Korean earthquake catalog. The combined earthquake catalog was prepared by performing earthquake clustering analysis on the collected earthquake catalogs provided by experts of the seismic panel during the PSA for Yonggwang Units 1 & 2. The duplicate earthquake events and secondary events in earthquake clusters have been successfully screened. The resultant earthquake catalog was analyzed to quantitatively assess the incompleteness of the earthquake catalog for specified earthquake magnitudes and time periods. The result shows that the earthquake catalog of the Korean peninsula is complete for the times periods of 1392 ~ 1750 and 1905 ~ 1989 (AD) and earthquake magnitude above 4.5. The PSHA methodology of EQHAZARD features the estimation of inhomogeneous a-and b-values within a seismic source. This study shows various results of a-and b-value is well constrained lying between o.6 and 1.0. Also the confidence of estimated a-and b-value for a specifed location was assessed by quantifing the uncertainty of these parameters using bootstrap simulation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.803-808
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• 2007

LCCA module enabling to estimate LCC and analyze time-variant reliability index of a plate girder bridge was developed. The developed module was based on the designed data structure following the standardized methodology of ISO/STEP, LCCA module consisted of LCC estimation module, which is composed of six sub modules according to the cost category, and reliability index analysis module, which is composed of time-variant corrosion sub module, time-variant live load sub module, and element reliability analysis sub module, The effectiveness of the developed LCCA module was verified by estimating LCC and analyzing time-variant reliability index of a plate girder bridge on the basis of the constructed test database.

• Journal of the Korea Society for Simulation
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• v.9 no.4
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• pp.1-10
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• 2000

One of the primary goals of the simulation experiments is to understand the overall system behavior and to analyze the system, ultimately to optimize the system. Optimizing the system includes determining the optimum condition of the system parameters of interest. This paper is concerned with the simulation methodology for estimating the unknown objective function for the system of interest and optimizing the system with respect to the controllable factors. In the process of estimating the unknown objective function, which is assumed to be a second order spline function, we use common random numbers for different set of the controllable factors resulting in more accurate parameter estimation for the objective function. We will show some mathematical result for the benefit of using common random numbers.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.55-59
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• 2003

In this paper, we estimate the performance requirements of general-purpose DSP for Carrier Recovery of OFDM DVB-T receiver. Firstly, we transported the designed fixed-point OFDM DVB-T model to a floating-point software model written in C. Then, we measured the number of instruction cycles required for operation of Carrier Recovery in time. We use SignalMaster$\^$TM/ DSP platform of LYRtech Inc. as a environment of estimation, and Simulink$\^$TM/ as a graphical interface, Code Composer StudioTM of TI as profiler and compiler, and SPW$\^$TM/ for presenting functional reliability and comparing the performance distortion with fixed-point model. As a result, we show the required number of DSPs in our DSP-based system, and introduce the need of Multi-DSP-based system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.6
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• pp.90-99
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• 2011

As power industry evolves into Smart Grid scheme, previously closed power systems are being integrated into public communication networks. It increases the controllability and efficiency of the system, but also accompanies many cyber threats having existed in the Internet to the SCADA system. Therefore it is required to apply security countermeasures to the Smart Grid, which brings about investment costs. There have been few approaches to assess risks from cyber attack especially in electric power industry. So this paper proposes a methodology to assess quantitative impacts of various types of cyber attacks to a power system, and also shows the feasibility of the method through a case study.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.12
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• pp.88-96
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• 2015

This paper describes a new method for enhancing the accuracy of network analysis applications in energy management systems. Topology processing, state estimation, power flow analysis, and contingency analysis play a key factor in the stable and reliable operation of power systems. In this respect, the aim of topology processing is to provide the electrical buses and the electrical islands with the actual state of the power system as input data. The results of topology processing is used to input of other applications. New method, which includes the topology error analysis based on inconsistency check, coherency check, bus mismatch check, and outaged device check is proposed to enhance the accuracy of network analysis. The proposed methodology is conducted by energy management systems and the Korean power systems have been utilized for the test systems.