• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.366-373
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• 2006

In order to reduce the secondary earthquake disaster resulting from the damage of gas facilities it is indispensable to establish an early response system on the basis of damage prediction. In this study the procedure of damage prediction for gas facilities is proposed and applied to the gas supply model area. Model area is divided into several little blocks. The soil condition and the characteristics of facilities were investigated at each block. Using fragility curves of facilities the damage level was analyzed under various seismicities. It is confirmed that the exposure gas pipe line in several blocks is damaged seriously by the collapse of building structures.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.89-96
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• 2006

Recently, many researches on the dissipation of excess pore pressure in liquefied sand grounds have been performed to evaluate post-liquefaction behaviors of structures. In this paper. centrifuge tests were performed to simulate liquefaction behaviors of prototype soil. The evaluation model of solidified layer thickness was developed to simulate non-linear variation of solidified layer thickness with time. Also, the dissipation of excess pore pressure in liquefied sand was evaluated by applying the solidification theory and the consolidation theory. The developed model gives a good estimation of the solidified layer thickness and the time history of excess pore pressure.

• Korean Journal of Remote Sensing
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• v.23 no.1
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• pp.15-20
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• 2007

This study is to apply QuickBird satellite image for the simulation of storm runoff in a small rural watershed. For a $1.05km^2$ watershed located in Goesan-Gun of Chungbuk Province, the land use from the QuickBird image was produced by on-screening digitising after ortho-rectifying using 2 m DEM. For 3 cases of land use, soil and elevation scale (1:5,000, 1:25,000 and 1:50,000), SCS-CN and the watershed physical parameters were prepared for the storm runoff model, HEC-HMS (Hydrologic Modelling System). The model was evaluated for each case and compared the simulated results with couple of selected storm events.

• Structural Engineering and Mechanics
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• v.22 no.1
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• pp.33-52
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• 2006

Three-dimensional description of building structure taking into consideration soil-structure interaction is a very complex problem and solution of this problem is often obtained by using finite element method. However, this method takes a significant amount of computational time and memory. Therefore, an efficient computational model based on subdivision of the structure into building elements such as wall and floor slab elements, plane and three-dimensional joints and lintels, that could provide accurate results with significantly reduced computational time, is proposed in this study for the analysis three-dimensional structures subjected to dynamic load. The examples prove the efficiency and the computing possibilities of the model.

• Earthquakes and Structures
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• v.10 no.3
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• pp.563-588
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• 2016

In this study, solution models are proposed to obtain code-compatible ground motion record sets which can be used for both uni-directional and bi-directional dynamic analyses. Besides scaled, unscaled ground motion record sets are obtained to show the utility and efficiency of the solution models. For scaled ground motion sets the proposed model is based on hybrid HS-Solver which integrates heuristic harmony search (HS) algorithm with the spreadsheet Solver add-in. For unscaled ground motion sets HS based solution model is proposed. Design spectra defined in Eurocode-8 for different soil types are selected as target spectra. The European Strong Motion Database is used to get ground motion record sets. Also, a sensitivity analysis is conducted to evaluate the effect of different HS solution parameters on the solution accuracy. Results show that the proposed solution models can be regarded as efficient ways to develop scaled and unscaled ground motion sets compatible with code-based design spectra.

• Earthquakes and Structures
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• v.3 no.3_4
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• pp.297-313
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• 2012

This paper is intended to show the robustness and capabilities of a coupled boundary element-finite element technique for the analysis of vibrations generated by high-speed trains under different geometrical, mechanical and operation conditions. The approach has been developed by the authors and some results have already been presented. Nevertheless, a more comprehensive study is presented in this paper to show the relevance and robustness of the method which is able to predict vibrations due to train passage at the vehicle, the track, the free-field and any structure close to the track. Local soil discontinuities, underground constructions such as underpasses, and coupling with nearby structures that break the uniformity of the geometry along the track line can be represented by the model. Non-linear behaviour of the structures can be also considered. Results concerning the excitation mechanisms, track behaviour and sub-Rayleigh and super-Rayleigh train speed are summarized in this work.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.8
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• pp.427-431
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• 2013

Ground heat pump systems utilize the annually stable underground temperature to supply heat for space heating and cooling. The underground temperature affects not only the underground ecosystem, but also the performance of these systems. However, in spite of the widespread use of these systems, there have been few researches on the effect of the systems on underground temperature. In this research, case studies with numerical simulation have been conducted, in order to estimate the effect of ground heat pump systems on underground temperature. The simulation was coupled with the ground water-ground heat transfer model and the ground surface heat transfer model. In the result, it was found that the underground change depends on the heat transfer from the ground surface, the heat exchange rate, and the heat conductivity of soil.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.410-419
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• 2018

Purpose: CLIMEX, a species distribution modeling tool, includes various types of parameters representing climatic conditions; the estimation of these parameters directly determines the model accuracy. In this study, we investigated the sensitivity of parameters for the climatic suitability calculated by CLIMEX for Metcalfa pruinosa in South Korea. Methods: We first changed 12 parameters and identified the three significant parameters that considerably affected the CLIMEX simulation response. Results: The result indicated that the simulation was highly sensitive to changes in lower optimal temperatures, lower soil moisture thresholds, and cold stress accumulation rate based on the sensitivity index, suggesting that these were the fundamental parameters to be used for fitting the simulation into the actual distribution. Conclusion: Sensitivity analysis is effective for estimating parameter values, and selecting the most important parameters for improving model accuracy.

• Journal of Soil and Groundwater Environment
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• v.13 no.1
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• pp.101-109
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• 2008

The adsorption characteristics of cationic metals such as copper, cadmium, and lead onto the amorphous aluminum oxide, AMA-L, which was mineralized from raw sanding powder at $550^{\circ}C$ were investigated. Additionally, surface complexation reaction of cationic heavy metals onto AMA-L was simulated with MINEQL + software employing a diffuse layer model. From the batch adsorption tests in a single element system, the adsorption affinity of each metal ion onto AMA-L was following order: lead > copper > cadmium. In a binary system composed with copper and cadmium, quite a similar adsorption affinity was observed in each metal ion compared to the single element system. When the surface complexation constants obtained in the single system were used in the prediction of experimental adsorption results, model predictions were well fitted with experimental results of both single and binary systems.

• Geotechnical Engineering
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• v.12 no.6
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• pp.5-20
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• 1996

This paper presents results from a series of model tests on laterally loaded single piles with both free-head and free-tip conditions. Model tests, using a centrifuge apparatus (middie size, Mark II in 7.1.7.) were carried out in sand based on the variation of different gravity acceleration and flexural stiffness of the pile and relative density of the soil. The aims of this study are to estimate the effect of gravity acceleratioil, flexordis stiffness, and relative density on the behavior of the pile embedded in Toyoura sand and to evaluate the applicability of a family of the p-y curves which was presented by several reseachers(Mur chison & O'Neill, neese et n., scott, Det worske veritas, nondner). The Program is deviloped by using p-y curves, and it can be used for the calculation of the displacement distri bution, bending moment distribution, and soil reaction distribution. By comparing meas ured responses with predicted one it is shown that the results of the p-y curve equation presented by Murchison & O'Neill and Kondner agreed with the general trend observed by the centrifuge tests much better than the numerical solutions predicted by the other sets of p -y curves.