• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.4
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• pp.31-37
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• 2003

This paper presents the methodologies for seismic retrofitting of cabinet equipment which can be employed to resolve the USI A-46 problem related to seismic qualification of old nuclear power plant. To obtain accurate dynamic characteristics of a cabinet structure, three types of structural modeling are introduced and the their free vibration modes are compared. Three types of seismic retrofitting scenarios, such as 1) the installation of bracing, 2) installation of damper, 3) installation of tuned mass damper(TMD), are established and evaluated for the decrease of ICRS(In Cabinet Reponse Spectrum). In the cases of 1) ＆ 2), since the retrofitted structures show larger ICRS than that of the original structure, the careful considerations are need in the application of these methods. Though the installation of TMD shows the best retrofitting result, the construction of analysis model that indicate the accurate vibration modes of real structure is estimated the essential step of this retrofitting method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.3
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• pp.203-211
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• 2023

A Markov chain Monte Carlo (MCMC) simulation is proposed for probabilistic full waveform inversion (FWI) in a layered half-space. Dynamic responses on the half-space surface are estimated using the thin-layer method when a harmonic vertical force is applied. Subsequently, a posterior probability distribution function and the corresponding objective function are formulated to minimize the difference between estimations and observed data as well as that of model parameters from prior information. Based on the gradient of the objective function, a proposal distribution and an acceptance probability for MCMC samples are proposed. The proposed MCMC simulation is applied to several layered half-space examples. It is demonstrated that the proposed MCMC simulation for probabilistic FWI can estimate probabilistic material properties such as the shear-wave velocities of a layered half-space.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.503-511
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• 1998

In this study, the stress distribution for different tibial components was observed In order to Investigate the load transfer and potential failure mechanism of the tibial components subjected to dynamic impact loading and also to evacuate the effect of bone-implant bonding conditions on the implant system. The 3-dimensional finite element models included an intact tibia, cemented metal-backed tibial component, uncemented metal-blocked tibial component, cemented all-polyethylene tibial component, and metal-backed component with a debonded bone/stem interface. The results showed that the cemented metal-hocked component Induced slightly higher peak stress at stem tip than the uncemented component. The peak stress of the all-polyethylene tibia1 component at stem trip showed about half thats of metal-backed tibial components. The all-polyethylene component showed a similar dynamic response to intact tibia. In case of debonded bone/stem interface, the peak stress below the metal tray was three times Higher than that of the fully bonded interface and unstable stress distribution at the stem tip was observed with time, which causes another adverse bone apposition and implant loosening. Thus, the all-polyethylene tibial component bonded fully to the surrounding bone might be most desirable system under an impact loading.

• Journal of the Korean GEO-environmental Society
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• v.18 no.4
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• pp.31-40
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• 2017

In this study, a simple method to evaluate the seismic vulnerability of river levees was examined considering the structural characteristic of river levee, that is long, and the functional characteristic of river levee that performs temporary function against flood but is a permanent structure in the ordinary way. Considering the fact that one of the main failure modes of the levee during the earthquake are the settlement due to the strength reduction of the ground caused by the increase of the excess pore pressure in the levee body and foundation and the settlement due to liquefaction, the 2-dimensional section of the levee was regarded as the 1-dimensional section and the liquefaction potential index (LPI) for the regarded section was estimated. The estimated LPI was correlated with the seismic vulnerability of river levees. The relationship between the displacement of the levee crest caused by the earthquake and the seismic vulnerability of the levees was obtained from the results of previous researches and the correlation between the displacements of the levee crest computed by 2-dimensional dynamic coupled analyses and LPIs based on the results of 1-dimensional seismic response analyses was investigated. In connection with this correlation, as a result of examination of the correlation between LPI and the seismic vulnerability of the levee, it was concluded that the method for evaluation of the seismic vulnerability of the Korean river levee using LPI is applicable.

• Journal of the Korean Geosynthetics Society
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• v.13 no.1
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• pp.71-83
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• 2014

Busan is located at the mouth of Nakdong River and if an earthquake occurs, it is very likely that the damage by the earthquake will be worse as liquefaction can happen in the sand layer, builtup soil, and landfill ground due to amplification in the lower sedimentary layer that is well developed in the river mouth. Therefore, this study first examined the possibility of liquefaction in the replaced sand layer under breakwater using 14 earthquakes in 5.6-7.9 scale and artificial earthquakes including the seismic wave suggested in the standard specifications for seismic design of ports and fishing port facilities to evaluate the stability of breakwater which is the primary protective structure for port facilities against earthquakes. Second, analysis on characteristics of the seismic energy and acceleration response spectrum by size of earthquake was performed to suggest the most appropriate size of seismic wave for the condition in Korea. Third, finite element analysis was performed using the suggested seismic wave to study the characteristics of earthquake by finding the dynamic lateral displacement of breakwater and verifying the stability of structure and the displacement and forces occurring at geotextile. Results of the study showed that the possibility of liquefaction in the landfill and replaced sand layer, the dynamic lateral displacement of breakwater, and changes of geotextile are greatly affected by the subsurface ground (replaced sand layer).

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1379-1385
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• 2007

In domestic transitional zone design, there is regulation to prevent generation of irregular substructure behaviors that negatively influence in prevention of plasticity settlement on approach section and contact section as well as relieve overall track rigidity by reducing sectional foundation and track stiffness difference, but design guideline that considers dynamic behavior of transitional track in actual service line is very insignificant. Therefore in this study, characteristics of transitional track dynamic behaviors by substructure stiffness are researched and measured dynamic response of transitional track by substructure stiffness in order to prove correlation between substructure and track and calculate elasticity(stiffness) and track load of transitional track by using measurement and formula to provide basic information for developing design guideline considering dynamic behavior of service line transitional track.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.1
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• pp.49-64
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• 2014

Seabed beneath and near the coastal structures may undergo large excess pore water pressure composed of oscillatory and residual components in the case of long durations of high wave loading. This excess pore water pressure may reduce effective stress and, consequently, the seabed may liquefy. If the liquefaction occurs in the seabed, the structure may sink, overturn, and eventually fail. Especially, the seabed liquefaction behavior beneath a gravity-based structure under wave loading should be evaluated and considered for design purpose. In this study, to evaluate the liquefaction potential on the seabed, numerical analysis was conducted using 2-dimensional numerical wave tank. The 2-dimensional numerical wave tank was expanded to account for irregular wave fields, and to calculate the dynamic wave pressure and water particle velocity acting on the seabed and the surface boundary of the structure. The simulation results of the wave pressure and the shear stress induced by water particle velocity were used as inputs to a FLIP(Finite element analysis LIquefaction Program). Then, the FLIP evaluated the time and spatial variations in excess pore water pressure, effective stress and liquefaction potential in the seabed. Additionally, the deformation of the seabed and the displacement of the structure as a function of time were quantitatively evaluated. From the analysis, when the shear stress was considered, the liquefaction at the seabed in front of the structure was identified. Since the liquefied seabed particles have no resistance force, scour can possibly occur on the seabed. Therefore, the strength decrease of the seabed at the front of the structure due to high wave loading for the longer period of time such as a storm can increase the structural motion and consequently influence the stability of the structure.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.300-313
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• 2014

Most analytical solutions for wave-induced soil response have been mainly developed to investigate the influence of the progressive and standing waves on the seabed response in an infinite seabed. This paper presents a new analytical solution to the governing equations considering the wave-induced soil response for the partial standing wave fields with arbitrary reflectivity in a porous seabed of finite thickness, using the effective stress based on Biot's theory (Biot, 1941) and elastic foundation coupled with linear wave theory. The newly developed solution for wave-seabed interaction in seabed of finite depth has wide applicability as an analytical solutions because it can be easily extended to the previous analytical solutions by varying water depth and reflection ratio. For more realistic wave field, the partial standing waves caused by the breakwaters with arbitrary reflectivity are considered. The analytical solutions was verified by comparing with the previous results for a seabed of infinite thickness under the two-dimensional progressive and standing wave fields derived by Yamamoto et al.(1978) and Tsai & Lee(1994). Based on the analytical solutions derived in this study, the influence of water depth and wave period on the characteristics of the seabed response for the progressive, standing and partial standing wave fields in a seabed of finite thickness were carefully examined. The analytical solution shows that the soil response (including pore pressure, shear stress, horizontal and vertical effective stresses) for a seabed of finite thickness is quite different in an infinite seabed. In particular, this study also found that the wave-induced seabed response under the partial wave conditions was reduced compared with the standing wave fields, and depends on the reflection coefficient.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.5
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• pp.533-541
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• 2021

Retaining walls have been used to prevent slope failure through resistance of earth pressure in railway, road, nuclear power plant, dam, and river infrastructure. To calculate dynamic earth pressure and determine the characteristics for seismic behavior, many researchers have analyzed the nonlinear response of ground and structure based on various numerical analyses (FLAC, PLAXIS, ABAQUS etc). In addition, seismic fragility evaluation is performed to ensure safety against earthquakes for structures. In this study, we used the FLAC2D program to understand the seismic response of the inverted T-type wall with a backfill slope, and evaluated seismic fragility based on relative horizontal displacements of the wall. Nonlinear site response analysis was performed for each site (S2 and S4) using the seven ground motions to calculate various seismic loadings reflecting site characteristics. The numerical model was validated based on other numerical models, experiment results, and generalized formula for dynamic active earth pressure. We also determined the damage state and damage index based on the height of retaining wall, and developed the seismic fragility curves. The damage probabilities of the retaining wall for the S4 site were computed to be larger than those for the S2 site.

• Journal of Global Scholars of Marketing Science
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• v.7
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• pp.303-320
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• 2001

The purpose of the study was to investigate the hedonistic motives experienced by consumers in the apparel buying process. We carried out in-depth interviews by 32 women living in Pusan and to examine the hedonistic motives related to the apparel buying process. It was conducted and analysed by the Spradley's developmental research method.The results showed that the hedonistic motives in apparel buying process, consisted of four components at least, such as Symbolism, Conformity, Distinction, and Impulsiveness. Symbolism represented the social-psychological aspects related to the apparel buying process, such as occupation, role, and self-image etc. Conformity in the apparel buying process was usually influenced by mass-media, and companions. Consumers had strong needs of distintion for self-actualization and self-esteem in apparel buying process. The impulsiveness in apparel buying process were related to the antecedent moods, affection, tastes, price, display, and sales person or accompanied friends. We found that the hedonistic motives in the apparel buying process connected with the emotional responses and were played an important role on the consumer satisfaction in the apparel buying process. They provide informations about hedonistic motives of apparels to consumer behavior researchers and retailers related to apparel products.