• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.976-977
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• 2005

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.187-190
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• 2003

In order to apply a cyclic elasto-plastic and a viscoelastic-viscoplastic constitutive model to actual multi-layered ground conditions during large earthquake, numerica simulations were performed by a liquefaction analysis in the present study. From the liquefaction analysis, it was verified that the models can give a good description of the damping characteristics and liquefaction phenomena of ground accurately during large event which induces plastic deformation in large strain range.

• Journal of the Korea Safety Management & Science
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• v.6 no.2
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• pp.177-186
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• 2004

Decision analysis has becomes an important technique for decision making in the face of uncertainty. It is characterized by enumerating all the available courses of action, identifying the payoffs for all possible outcomes, and quantifying the subjective probabilities for the all possible random events. When the data are available, decision analysis becomes a powerful tool for determining an optimal course of action. We study the multi-attribute decision making in a compensatory models. In this paper, we use the entropy methods in weights calculating. For the purpose of making optimal decision, the data of five different car models are used. For computing, we used Visual Numerica Version 1.0 software package.

• Proceedings of the Safety Management and Science Conference
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• 2006.04a
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• pp.123-131
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• 2006

Multi-criteria decision making is deducing the relative importance in the criterion of decision making and each alternative which is able to making a variety of choices measures the preferred degree in the series of low-raking criterions. Moreover, this is possible by synthesizing them systematically. In general, a fundamental problem decision maker solve for multi-criteria decision making is evaluating a set of activities which are considered as the target logically, and this kind of work is evaluated and synthesized by various criterions of the value which a chain of activities usually hold in common. In this paper, we are the eigenvector methods in weights calculating. For the purpose of making optimal decision, the data of five different car models are used. For computing, we used Visual Numerica Version 1.0 software package.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1925-1928
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• 1996

In this work, the behavior of conducting wire type particles existing inside the cylinder type coaxial electrode has been systematically investigated by charge simulation method and electrostatic force analysis from the view point of the acquired charging before being lifted off into the gap under the high ac voltage. Spheroidal charge are adopted as a image charge for the CSM analysis in order to calculate the acquired charges of the particles which are erected on the surface of the outer electrode. For this purpose, different material of the particle and their lengths and diameters have been considered in view to calculate their lift-off field, acquired charge and to understand their effect on the lift-off voltage. The results imply that the particle lengths and diameter have an different influence on the particle behavior in GIS system.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.2
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• pp.73-85
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• 1995

This study aimes at investigating the applicability of single surface work - hardening model(7, 8) to clayey soils through FEM analysis. The comparison was carried out for the results between numericaL analysis and cubical triaxial tests in which confined stress was applied differently and 3-directional principal stress can be controlled. Furthermore, the results of the numerical analysis were compared with observed values of load test on the 2-dimensional model foundation composed of clayey soils. The agreement between nu- merical and observed values proved to be of high accuracy, which indicates that numeri- cal techniques developed during this study using the model can be used for the prediction of settlement, leteral displacement and pore water pressure of actual soft foundation of clayey soils.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.727-736
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• 2001

Dentinal hypersensitivity is one of the complicated symptom rather than a disease. It has special reaction or pain over uncovered root by heat, mechanical or chemical stimulations, which are normal with healthy teeth, The purpose of this study is to discover rather MS Coat (oxalate-containing pre-polymerized resin suspension) or Elmex gel(amine fluoride+sodium fluoride) is effective on hypersensitivity after periodontal treatment using NRS(Numerica1 Rating Scales), which it is useful for evaluating pain level. This study has been prepared in Dankook Dental Hospital with generally healthy adult who had been suffered from dentinal hypersensitivity after periodontal treatment. Divided in three groups with saline(control group), MS Coat(test 1 group) and Elmex gel(test 2 group). And then, following evaluations were made at the end of 1 minute, 1 week, 1 month and 3 months. 1. The sequence of higher frequency & severeness of hypersensitivity is water within $7^{\circ}C$, air stream & explorer. 2. As time goes on, 1 minute, 1 week, 1 month & 3 months, severeness of hypersensitivity scored lower with water, air stream and explorer. 3. With explorer, the differences among three groups as time had to seen. 4. With air stream, the sensitivity scored lower after 1min with MS Coat, Elmex, and saline sequence. As time goes on the sensitivity was lower with MS Coat and Elmex than saline, but there was no difference between MS Coat and Elmex. 5. With water in $7^{\circ}C$, the sensitivity was much decreasing with MS Coat and Elmex than saline, but there was no difference between MS Coat and Elmex. As the result, MS Coat and Elmex are effective on hypersensitivity caused by periodontal treatment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.2
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• pp.55-63
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• 1998

Recently the modified mild-slope equation has been developed by several researchers using different approaches, which, compared to the Berkhoff's mild-slope equation, includes additional terms proportional to the square of bottom slope and to the bottom curvature. By examining this equation, it is shown that both terms are equally important in intermediate-depth water, but in shallow water the influence of the bottom curvature term diminishes while that of the bottom slope square term remains significant. In order to examine the importance of these terms in more detail, the modified mild-slope equation and the Berkhoff's mild-slope equation are tested for the problems of wave reflection from a plane slope, a non-plane slope, and periodic ripples. It is shown that, when only the bottom slope is concerned, the mild-slope equation can give accurate results up to a slope of 1 in 1 rather than 1 in 3, which, until now, has been known as the limiting bottom slope for its proper application. It is also shown that the bottom curvature term plays an important role in modeling wave propagation over a bottom topography with relatively mild variation, but, where the bottom slope is not small, the bottom slope square term should also be included for more accurate results.