• Journal of the Korean Society of Hazard Mitigation
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• 제9권1호
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• pp.151-158
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• 2009

Many people have been suffering and loosing their property from inundation due to concentrated rain and massive storm. Although, river banks are strengthened and pumping stations are constructed to protect the life and property of people, the flood damages (disaster)could not be controlled, in fact it is increasing. In USA, CWMS (Corps Water Management System) has very good system of integration of study of rainfall data, computation of stream stage and simulation of flood damages, but there is lack of this type of study and analysis in the domestic context, so we have been facing many difficulties in simulation of flood damages. Therefore, a systematic collecting of data analysis and evaluation of flood damages is necessary. The main objective of this study is to suggest a systematic data collection and evaluation method, which could be useful to prevent the life and property from unusual damages. In this study, the system (Flood Damage Evaluation Model; K-FDEM) is proposed to evaluate the flood damages from rainfall with considering many field parameters.

• Convergence Security Journal
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• 제21권1호
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• pp.115-120
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• 2021

An O2O-based real estate brokerage web sites or apps are increasing explosively. As a result, the environment has been changed from the existing offline-based real estate brokerage environment to the online-based environment, and consumers are getting very good feelings in terms of time, cost, and convenience. However, behind the convenience of online-based real estate brokerage services, users often suffer time and money damage due to false information or malicious false information. Therefore, in this study, in order to reduce the damage to consumers that may occur in the O2O-based real estate brokerage service, we designed a false property information filtering system that can determine the authenticity of registered property information using artificial intelligence technology. Through the proposed research method, it was shown that not only the authenticity of the property information registered in the online real estate service can be determined, but also the temporal and financial damage of consumers can be reduced.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.252-253
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• 2017

The appearance & spread of new kind of virus might cause national economic shrinkage and reduction of foreign tourist. Finally, severe damage of national economy happens. This research wants that after property analysis for generally applied building interior materials, specifically eco-environmental materials including functional materials are reviewed, classified and their special properties in building were investigated.

• Journal of Ocean Engineering and Technology
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• 제18권2호
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• pp.25-32
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• 2004

We surveyed the coastal structure damage created by typhoon ‘Maemi’, which heavily struck the Korean peninsula on September 12, 2003. The survey revealed that high tides and strong winds induced by the typhoon were the main causes of the coastal damage, especially in the Busan areas. Though some experimental real-time coastal monitoring stations captured the typhoon movements at the critical time, more systematic and complete system should be implemented to save human lives and property from huge typhoon disasters.

• Smart Structures and Systems
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• 제2권2호
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• pp.127-140
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• 2006

In this study, a wavelet-based covariance-driven system identification technique is proposed for damage assessment of structures under ambient excitation. Assuming the ambient excitation to be a white-noise process, the covariance computation is shown to be able to separate the effect of random excitation from the response measurement. Wavelet transform (WT) is then used to convert the covariance response in the time domain to the WT magnitude plot in the time-scale plane. The wavelet coefficients along the curves where energy concentrated are extracted and used to estimate the modal properties of the structure. These modal property estimations lead to the calculation of the stiffness matrix when either the spectral density of the random loading or the mass matrix is given. The predicted stiffness matrix hence provides a direct assessment on the possible location and severity of damage which results in stiffness alteration. To demonstrate the proposed wavelet-based damage assessment technique, a numerical example on a 3 degree-of-freedom (DOF) system and an experimental study on a three-story building model, which are all under a broad-band excitation, are presented. Both numerical and experimental results illustrate that the proposed technique can provide an accurate assessment on the damage location. It is however noted that the assessment of damage severity is not as accurate, which might be due to the errors associated with the mode shape estimations as well as the assumption of proportional damping adopted in the formulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.227-230
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• 2009

In order to predict failure behavior of advanced high-strength steel sheets (AHSS) in hole expansion tests, damage model was developed considering surface condition sensitivity (with specimens prepared by milling and punching: 340R, TRIP590, TWIP940). To account for the micro-damage initiation and evolution as well as macro-crack formation, the stress triaxiality dependent fracture criterion and rate-dependent hardening and ultimate softening behavior were characterized by performing numerical simulations and experiments for the simple tension and V-notch tests. The developed damage model and the characterized mechanical property were incorporated into the FE program ABAQUS/Explicit to perform hole expansion simulations, which showed good agreement with experiments.

• Transactions of Materials Processing
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• 제3권1호
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• pp.120-132
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• 1994

Strip drawing of strain-hardening, viscoplastic materials with damage is analyzed by a rigid plastic finite element method. A process model is formulated using two state variables, one for strain hardening from slip dominated plastic distortion and the other for damage from growth of microvoids. Application of the model to aluminum strip drawing is given via implementation in a consistent penalty finite element formulation. The predicted density changes as a result of void growth are compared to those from experiments reported in the literature. The effects of drawing conditions such as drawing speed and die angle on the mechanical property chages are studied.

• Transactions of the Korean Society of Mechanical Engineers
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• 제19권4호
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• pp.1033-1040
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• 1995

To simulate strength reliability and durability of ceramic parts under gas turbine application environments, particle impact damage behaviors in silicon carbide oxidized at 1673 K and 1523 K for 200 hours in atmosphere were investigated. The long-term oxidation produced a slight increase in the static fracture strength. Particle impact caused a spalling of oxide layer. The patterns of spalling and damage induced were dependent upon the property and impact velocity of the particle. Especially, the difference in spalling behaviors induced could be explained by introducing the formation mechanism of lateral crack and elastic-plastic deformation behavior at impact sit. At the low impact velocity regions, the oxidized SiC showed a little increase in the residual strength due to the cushion effect of oxide layer, as compared with the as-received SiC without oxide layer.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.164-165
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• 2014

In the case of U.S, various damage prediction models of buildings from natural disasters have been used widely in many organizations such as insurance companies and governments. In South Korea, although studies regarding damage prediction model of hurricane have been conducted, the scope has been only limited to consider the property of hurricane. However, it is necessary to consider various factors such as socio-economic, physical, geographical, and built environmental factors to predict the damages. Therefore, as a basic study on a damage prediction model development of buildings, this study is to analyze the correlation between various factors related to hurricane. The findings of study can be utilized to develop for predicting the damage of hurricane on buildings.

• Proceedings of the Korean Society For Composite Materials Conference
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.171-174
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• 2004

In order to improve the damage tolerance of the conventional laminated composites, three­dimensional fiber structures incorporated with stitching yams have been utilized in this study. From the newly developed process termed as TAPIS(TApe Placement Incorporated with Stitching), carbon/epoxy composites have been fabricated. Two-dimensional composites with the same stacking sequence as 3D counterparts have also been fabricated for the property comparison. To examine the damage resistance performance the low speed drop weight impact test has been adopted. For the assessment of damage after the impact loading, specimens were subjected to C-scan nondestructive inspection compression after impact(CAI) were also conducted to evaluate residual compressive strength. Although the damage area of 3D composites was greatly reduced$(30-40\%)$ compared with that of 2D composites, the CAI strength did not show drastic improvement.