• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.761-768
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• 2000

In order to investigate how the fatigue damage effects on the critical properties of superconductor, a fatigue test at room temperature and an Ic measurement test at 4.2K were carried out in this study, respectively, using a 9 strand Cu-Ni/NbTi/Cu composite cable. Through the fatigue test of a 9 strand Cu-NUNbTi/Cu composite cable, a conventional S-N curve was plotted even though there was a possibility of fretting among strands. It was found that the maximum stress corresponding to the inflection point on the S-N curve obtained was nearly the same value as the yielding strength of cable obtained from the static tensile test. However, the effect of cabling in multi-strands superconducting cable on the fatigue strength was not noticeable. The critical current(Ic) measurement was carried out at 4.2K in a NbTi strand out of the fatigued cable. It showed a degradation of lc at high stress amplitude regions over 380NTa, and the degradation became significant as the applied stress amplitude increased.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.4
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• pp.337-342
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• 2001

A natural disaster occupies a considerable part among various damages, and the damage of human lifes and property by heavy rain extends to hundreds, and billions in every you. In old times, flood was mainly occurred in big river or sudden slope, but these days, the damage of concentrated heavy rain is being extended to a city. Recently, very big floods occurred continuously, so real time submersion expectation system which can expect the inundation boundary according to the scale is needed so as to protect lifes and property. In this study, in and around Jungrang river, where the damage of flood is big, is chosen as a sample, and the submersion of that area is expected by analyzing the flux and overflowing using DEM, and connecting with Web GIS in real time.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.12
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• pp.3847-3855
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• 1996

In order to study the relationship between static and cynamic behaviors of silion caride, both quasi-static indentaiton and impact experiments of spherical particle have been conducted. The difference inmaterial behavior when using the two mehtods suggests a loading rate difference in the damate pattrern and fracture strength of silicon carbide. This investigation showed some difference in damage pattern according to particla property, especially inthe case of particle impact. There was no differences in deformation behaviors according to the loading rate when the crater profiles were compared with each other at the same contact radius. From the result of residual strength evaluation, it was found that the strength degradation began at the initiation of ring crack and its behavior was colsely related to morphologies of the damage developed which was also dependent upon the extent of deformation atthe loaidng point. In the case of static indentation, there didnot exist the particle property effects onthe strength degradation behavior.

• Atmosphere
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• v.34 no.2
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• pp.107-121
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• 2024

In this study, we empirically analyzed the impact of physical risks due to climate change on the soundness and operational performance of the financial industry by combining economics and climatology. Particularly, unlike previous studies, we employed the Seasonal-Trend decomposition using LOESS (STL) method to extract trends of climate-related risk variables and economic-financial variables, conducting a two-stage empirical analysis. In the first stage estimation, we found that the delinquency rate and the Bank for International Settlement (BIS) ratio of commercial banks have significant negative effects on the damage caused by natural disasters, frequency of heavy rainfall, average temperature, and number of typhoons. On the other hand, for insurance companies, the damage from natural disasters, frequency of heavy rainfall, frequency of heavy snowfall, and annual average temperature have significant negative effects on return on assets (ROA) and the risk-based capital ratio (RBC). In the second stage estimation, based on the first stage results, we predicted the soundness and operational performance indicators of commercial banks and insurance companies until 2035. According to the forecast results, the delinquency rate of commercial banks is expected to increase steadily until 2035 under assumption that recent years' trend continues until 2035. It indicates that banks' managerial risk can be seriously worsened from climate change. Also the BIS ratio is expected to decrease which also indicates weakening safety buffer against climate risks over time. Additionally, the ROA of insurance companies is expected to decrease, followed by an increase in the RBC, and then a subsequent decrease.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.32-40
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• 2019

This study analyzed operating condition and the problems of damage compensation insunace (property insurance) for qualified architect and derived some suggsetions for improvement. The Certified Architects Act requires all building design and construction supervision to buy property insurance. This study proposes following suggestions to solve problems of current architect property insurance. Firstly, we need to increase the insurance purchasing rate of damage compensation insurance for qualified architect. It is necessary to clearly specify the matters concerning the submission of insurance policies by the architects, which is currently carried out by the Minister's official letter, in the form of official announcement. Secondly, proper insured amount should be adjusted. In order to insured substantial compensation capacity, total amount of insurance should be enlarged. Thirdly, the insurance period should be extended to one year after completion of building to allow compensation for accidents due to design negligence. Generally, the design defect can mostly be identified within one year after completion. Fourthly, insurance coverage should be extended. In the long run, it is essential to enlarge the scope of the security not only to property damage but also to human losses. Finally, an accident record sharing system should be established among insurance companies, so that proper insurance premiums or discounts can be made based on the system.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.105-113
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• 2010

This study is for the preservation plan of the tradition space which is performed by the damage status analysis through performing the value assessment. Especially, it is an experimental study for finding the process and methods by analyzing the major element for the value assessment of the selected object's damage status through the expert group who are systematized in their interest to conserve the traditional structure in traditional space. For that purpose, this study should be performed by the fundamental understanding of the physical property of the Supyo-bridge and the condition of the selected site's environment. Meanwhile, this study has been done that 'map of the damage status distribution' for making records of damage status of the Supyo-bridge on the property utilized field measurement adapted by photogrammetry and assessment guidelines, which are for investigation on damage status of objects that are standardized 'Raccomandazioni Normal' which could be said construction culture assets management guidelines of Italian government. As the result of investigation, damage status of each part in the Supyo-bridge was mostly composed of damage by sediment and corrosion and in case of 9 damage types including corrosion, in consideration of physical and chemical properties and distribution status of those elements, it is made an judgement that is not working as a threatened factor regarding security of the Supyo-bridge. On the contrary, for the improvement landscape, in case of 'Thermoclastism' phenomenon observed in 'upper floor', 'Myungae stone' and 'bridge pier' is that when taking it into consideration that is widely distributed concentrated on the bridge pier, surface reinforcement job along with elimination of damage part will be judged to be requested for earliest treatment.

• Magazine of the Korea Concrete Institute
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• v.7 no.2
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• pp.117-125
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• 1995

In this study, the damage to a concrete br~dge pier due to flre caused by the fall of an oil truck were investigated by the use of FEM and by tensile tests for reinfortements. And thtse results were analyzed and compared with the measured values. In the FEM calculations, the selected variable was the fire temperature $T_a=500-800^{\circ}C$. The fixed values were the heat transition coefficient ${\alpha}=2000W/m^2{\cdot}K$. the initial temperature of concrete $T_0=5{\circ}C$ and the fire duration t=30 minutes. As the results obtained from numerical calculations, the property darrlage zone ap,)eared to be 1.5-4.1cm and the structure damage zone appeared to be 8.7- 10.1cm from the concrete surface. And this results give values very similar to those measured, nanlelv 2-4cm and 8~10cm respectively. The results frorn tensile tests give no serious loss of the tensile strength.

• Korean Journal of Heritage: History & Science
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• v.48 no.3
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• pp.138-153
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• 2015

For preventing the biological damage domestically, insect damage control method using chemical medicine has been applied. However, it is trend to avoid existing chemical medicine such as Methyl bromide because of the problem of being harmful to human body and environment. Therefore, the research for new medicine to replace this has been done and the interest to the physical treatment such as temperature(high & low) treatment, hypoxic treatment, carbon dioxide treatment, and radiation treatment has increased. However the systematic application standard and way has not been established. Therefore, in this research, we are going to organize present condition of domestic cultural asset preventing biological damage after the 1980's. It will also consider the direction through the characteristic of technology, limit, and replacement medicine by examining the past research.

• Computational Structural Engineering : An International Journal
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• v.1 no.1
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• pp.59-69
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• 2001

This study is intended to propose a systematic approach for reliability-based assessment of life cycle cost (LCC) effectiveness and economic efficiency for cost-effective seismic upgrading of existing bridges. The LCC function is expressed as the sum of the upgrading cost and all the discounted life cycle damage costs, which is formulated as a function of the Park-Ang damage index and structural damage probability. The damage costs are expressed in terms of direct damage costs such as repair/replacement costs, human losses and property damage costs, and indirect damage costs such as road user costs and indirect regional economic losses. For dealing with a variety of uncertainties associated with earthquake loads and capacities, a simulation-based reliability approach is used. The SMART-DRAIN-2DX, which is a modified version of the well-known DRAIN-2DX, is extended by incor-porating LCC analysis based on the LCC function developed in the study. Economic efficiencies for optimal seismic upgradings of the continuous PC segmental bridges are assessed using the proposed LCC functions and benefit-cost ratio.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.373-380
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• 2004

This paper presents the feasibility of an impedance-based damage detection technique using piezoelectric (PZT) transducers for civil infrastructures such as steel bridges. The impedance-based damage detection method is based on monitoring the changes in the electrical impedance. Those changes in the electrical impedance are due to the electro-mechanical coupling property of the piezoelectric material and structure. An effective integrated structural health monitoring system must include a statistical process of damage detection that is automated and real time assessment of damage in the structure. Once measured, damage sensitive features from this impedance change can be statistically quantified for various damage cases. The results of the experimental study on three kinds of structural members show that cracks or loosened bolts/nuts near the PZT sensors may be effectively detected by monitoring the shifts of the resonant frequencies. The root mean square (RMS) deviations of impedance functions between before and after damages were also considered as a damage indicator. The subsequent statistical methods using the impedance signature of the PZT sensors were investigated.