• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.63-71
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• 2013

The estimation of occupant injury risk at crash accident is one of the most important assessments for the vehicle crashworthiness performance. The design of safety devices such as occupant restraining system also depend on the kinematics of occupant and its injury risk. The real world in-depth accident investigation provides detailed and realistic information of vehicle damage and occupant injury as well as the accident conditions. This paper introduces a statistical analysis of NASS/CDS database and domestic accident data to correlate speed change, vehicle damage extend, and occupant injury at frontal crash. The maximum crush extend shows a linear relationship with the effective impact speed. The injury risks of the occupant with and without restraining were also respectively quantified with the crush extend. This result can be effectively used for the emergent rescue of crash victims with automatic crash notification system.

• The Journal of Fisheries Business Administration
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• v.41 no.2
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• pp.135-151
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• 2010

Conventional studies concerning about economic evaluation of fisheries damages caused by public undertakings have focused on showing the causality between marin environmental variation and fisheries production. But almost all of them have ignored the effect of fisheries damages factors on fisheries price. The study tries to suggest a model how to examine the existence and measurement of the effect of fisheries damage factors on fisheries price using statistical approach, in other words, the estimation of the statistical coincidence between two different population means. The paper tries to give a good application of the model using the case of fisheries damages caused by oil leakage pollution which happened three years ago in the coast of Taean province.

• Wind and Structures
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• v.31 no.1
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• pp.1-14
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• 2020

This paper presents a method of estimation of fatigue demands on connection bolts of tubular steel wind turbine towers. The presented method relies on numerical simulation of aerodynamic loads and structural behavior of bolted connections modeled using finite element method. Variability of wind parameters is represented by a set of values derived from their probability densities, which are adjusted based on field measurements. Numerically generated stress time-series show agreement with the measurements from strain gauges inside bolts, in terms of power spectra and the resulting damage. Position of each bolt has a determining effect on its fatigue damage. The proposed framework for fatigue life estimation represents the complexities in loading and local behavior of the structure. On the other hand, the developed procedure is computationally efficient since it requires a limited number of simulations for statistically representing the wind variations.

• Structural Monitoring and Maintenance
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• v.9 no.2
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• pp.157-177
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• 2022

In this paper, an innovative finite element updating method is presented based on the variation wavelet transform coefficients of Auto/cross-correlations function (WTCF). The Quasi-linear sensitivity of the wavelet coefficients of the WTCF concerning the structural parameters is evaluated based on incomplete measured structural responses. The proposed algorithm is used to estimate the structural parameters of truss and plate models. By the solution of the sensitivity equation through the least-squares method, the finite element model of the structure is updated for estimation of the location and severity of structural damages simultaneously. Several damage scenarios have been considered for the studied structure. The parameter estimation results prove the high accuracy of the method considering measurement and mass modeling errors.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.6
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• pp.293-303
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• 2021

Seismic fragility functions for unreinforced masonry buildings were derived based on the incremental dynamic analysis of eight representative inelastic numerical models for application to Korea's earthquake damage estimation system. The effects of panel zones formed between piers and spandrels around openings were taken into account explicitly or implicitly regarding stiffness and inelastic deformation capacity. The site response of ground motion records measured at the rock site was used as input ground motion. Limit states were proposed based on the fraction of structural components that do not meet the required performance from the nonlinear static analysis of each model. In addition to the randomness of ground motion considered in the incremental dynamic analysis explicitly, supplementary standard deviation due to uncertainty that was not reflected in the fragility assessment procedure was added. The proposed seismic fragility functions were verified by applying them to the damage estimation of masonry buildings located around the epicenter of the 2017 Pohang earthquake and comparing the result with actual damage statistics.

• Earthquakes and Structures
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• v.18 no.2
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• pp.249-261
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• 2020

Seismic loss estimation studies require fragility curves which are usually derived using ground motion datasets. Ground motion records can be either in the form of recorded or simulated time histories compatible with regional seismicity. The main purpose of this study is to investigate the use of alternative ground motion datasets (simulated and real) on the fragility curves. Simulated dataset is prepared considering regional seismicity parameters corresponding to Erzincan using the stochastic finite-fault technique. In addition, regionally compatible records are chosen from the NGA-West2 ground motion database to form the real dataset. The paper additionally studies the effects of hazard variability and two different fragility curve derivation approaches on the generated fragility curves. As the final step for verification purposes, damage states estimated for the fragility curves derived using alternative approaches are compared with the observed damage levels from the 1992 Erzincan (Turkey) earthquake (Mw=6.6). In order to accomplish all these steps, a set of representative masonry buildings from Erzincan region are analyzed using simplified structural models. The results reveal that regionally simulated ground motions can be used alternatively in fragility analyses and damage estimation studies.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.913-920
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• 1996

In this study, the counting method for multi-axial and multi-point load states was proposed. Using this counting method, the load spectrum is generated from the service load history which is measured for boom structure of excavator. Loading state for loading points of boom structure is described as a multi-dimensional state space. From this load spectrum, the stress spectrum was generated by FEM analysis using the superposition of the unit load. The cumulated damage at the severe damage point of In nm structure by the failure example is calculated by Palmgren-Miner's rule. As a result of this study, the fatigue life estimation using the multi-axial and multi-point load counting method is useful.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.119-126
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• 1996

In this paper, a method of substructural identification is presented for the estimation of localized structural parameters. for this purpose, an auto-regressive and moving average with stochastic input (ARMAX) model is derived for the substructure to process the measurement data impaired by noises. The sequential prediction error method is used fer the estimation of unknown localized parameters. Using the substructural method, the number of unknown parameters can be reduced and the convergence and accuracy of estimation can be improved. For some substructures, the effect of the input excitation is expressed in terms of the responses at the inferences with the main structure, and substructural identification may be carried out without measuring the actual input excitation to the whole structure. Example analysis is carried out for idealized structural models of a multistory building and a truss bridge. The results indicate that the present method is effective and efficient for local damage estimation of complex structures.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.85-93
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• 2005

It has been commonly assumed that during the 21st century, the korean peninsula may suffer huge earthquake damage to people, society, and economic system. The recent report of "Seoul Earthquake Response model development" conducted by the city of Seoul indicated that a magnitude 6.3 earthquake possibly hit Seoul, the capital of Korea. However, due to the insufficient amount of study on seismic performance of structures reflecting the various types of element peculiar to Korea application of the currently available earthquake damage evaluation methods has limitations. In order to conduct various studies on seismic hazards that are suitable for the actual conditions in Korea, therefore, fundamental studies first have to be properly conducted. The purpose of this study is to serve as the basis of establishing a reliable earthquake damage estimation system, and to provide essential data for the seismic damage evaluation of nonseismically reinforced concrete apartment structures. In this study, a standard type of nonseismically reinforced concrete apartments has been determined based on an extensive survey and careful review of such structures in Korea, and their performance level on seismic loading has been estimated.