• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.93-97
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• 2009

We analyzed voltage characteristics of toner particle type display according to particle layers and cell gap between two electrodes and ascertained the aging effects by measuring the response time of particles with and without aging process. The threshold/driving/breakdown voltage is proportional to layers of toner particles and cell gap and the response time at driving voltage is faster than that of threshold and breakdown voltage because of different q/m of color and black particles. The analysis of response time is a method of estimation of optical characteristics, driving voltage and particle lumping and these results are promoted by aging process. We use the laser and photodiode to measure response time and optical properties. It has not been studied and reported to analyze the relationship of response time, threshold/driving/breakdown voltage, lumping phenomena, cell gap, and aging process for toner particle type display.

• Structural Engineering and Mechanics
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• v.15 no.6
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• pp.717-733
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• 2003

A time domain method is presented for soil-structure interaction analysis under seismic excitations. It is based on the finite element formulation incorporating infinite elements for the far field soil region. Equivalent earthquake input forces are calculated based on the free field responses along the interface between the near and far field soil regions utilizing the fixed exterior boundary method in the frequency domain. Then, the input forces are transformed into the time domain by using inverse Fourier transform. The dynamic stiffness matrices of the far field soil region formulated using the analytical frequency-dependent infinite elements in the frequency domain can be easily transformed into the corresponding matrices in the time domain. Hence, the response can be analytically computed in the time domain. A recursive procedure is proposed to compute the interaction forces along the interface and the responses of the soil-structure system in the time domain. Earthquake response analyses have been carried out on a multi-layered half-space and a tunnel embedded in a layered half-space with the assumption of the linearity of the near and far field soil region, and results are compared with those obtained by the conventional method in the frequency domain.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.3 s.22
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• pp.29-35
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• 2006

Fiber element method in earthquake response analysis of bridges is used to represents a realistic flexural deformation according to nonlinear behavior of beam-column section. Nonlinear pseudo-static analysis of two column bent using fiber element is accomplished and failure mechanism of the plastic hinge region is studied. Load-displacement curve obtained by nonlinear pseudo-static analysis can be applicable to earthquake response analysis by capacity spectrum method. The nonlinear time history analysis of a full bridge model using fiber element experienced by the ground motion corresponding to the target response spectrum is accomplished. The result of time history analysis is similar to that of capacity spectrum method.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.6
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• pp.267-275
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• 2020

In the event of an earthquake, non-structural components require seismic performance to ensure evacuation routes and to protect lives from falling non-structural components. Accordingly, the seismic design code proposes horizontal force for the design and evaluation of non-structural components. Ground motion observed on each floor is affected by a building's eigen vibration mode. Therefore, the earthquake damage of non-structural components is determined by the characteristics of the non-structural component system and the vibration characteristics of the building. Floor response spectra in the seismic design code are estimated through time history analysis using seismic waves. However, it is difficult to use floor response spectra as a design criterion because of user-specific uncertainties of time history analysis. In addition, considering the response characteristics of high-rise buildings to long-period ground motions, the safety factor of the proposed horizontal force may be low. Therefore, this study carried out the horizontal force review proposed in the seismic design code through dynamic analysis and evaluated the floor response of seismic waves considering buildings and predominant periods of seismic waves.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.396-404
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• 2005

Nonlinear responses of structures may be obtained through three different methods. They are time-history analysis techniques, response spectrum method, and R-factor method. The nonlinear response spectrum method is frequently used in the practice, because the time history analysis method is time-consuming and complicated. There are two different approaches in obtaining the nonlinear response spectrum, which results in "constant displacement ductility spectra" and "constant damage spectra", respectively. The nonlinear response spectra of the various time-histories had been computed and the results were comparatively evaluated in this study. The study results showed that the existing constant displacement ductility spectra can induce unconservative design especially for the structures on soft soil base. This unconservatism can be removed by using the newly proposed constant damage spectra.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.787-789
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• 2013

A lot of applications are being developed as a result of popular smart machinery. Especially, Android OS that has high market share in smart phone market, applications are being developed and resulted. response time is delayed because service process of application do not work well although the space for using resource is enough. The purpose of this paper, analysis tool analyze response time of application to grope for an answer to the question about delayed response time of application.

• Structural Engineering and Mechanics
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• v.54 no.4
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• pp.809-827
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• 2015

In this paper, seismic energy response of inelastic steel structures under earthquake excitations is investigated. For this purpose, a numerical procedure based on nonlinear dynamic analysis is developed by considering material, geometric and connection nonlinearities. Material nonlinearity is modeled by the inversion of Ramberg-Osgood equation. Nonlinearity caused by the interaction between the axial force and bending moment is also defined considering stability functions, while the geometric nonlinearity caused by axial forces is described using geometric stiffness matrix. Cyclic behaviour of steel connections is taken into account by employing independent hardening model. Dynamic equation of motion is solved by Newmark's constant acceleration method in the time history domain. Energy response analysis of space frames is performed by using this proposed numerical method. Finally, for the first time, the distribution of the different energy types versus time at the duration of the earthquake ground motion is obtained where in addition error analysis for the numerical solutions is carried out and plotted depending on the relative error calculated as a function of energy balance versus time.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.117-123
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• 2021

This study aims to analyze working hours of sprinkler heads when a fire occurs at an indoor gymnasium while sprinkler heads are installed in division of standard response type, special response type, and earlier response type. The fire scenario was designed under the assumption that the fire started from overheating of a heater in the indoor gymnasium has transferred on to a couch to spread. The analysis on the operation time of the standard response type sprinkler head, the special response type sprinkler head and the early response sprinkler head was conducted. The result showed that, in case of fire in a gymnasium, the time for opening of the heat sensor due to the heat from the fire varies by the type of the sprinkler head. When a special response type sprinkler is installed, it worked below the assessment standards. When an early response sprinkler head is installed, it worked appropriately according to assessment standards. Based on the results, we found that sprinkler heads will work properly when installed according to design relevant to laws and regulations. This means that there is a limit in installation of sprinkler heads based on the existing law-based design as for indoor gymnasiums. Again, we conclude that if sprinkler heads are installed based on design made through laws and regulations, more time will be needed for operation, making it highly likely to fail to stop a fire at an earlier point of time.

• Journal of the Korean Society of Safety
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• v.39 no.2
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• pp.28-37
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• 2024

The recent surge in the production and handling of hazardous materials in Korea necessitates developing and implementing robust emergency response plans. These plans are crucial in safeguarding the well-being of workers and residents in the event of an incident. The consequence analysis methodology outlined in the KOSHA guidelines provides a foundation for designing emergency response plans in the event of chemical accidents. However, the consequence analysis is evaluated based on assumed accident cases or worst-case scenarios. Consequently, the emergency response plan based on the consequence analysis may overestimate the damage area, complicating rescue efforts and unnecessarily increasing costs. More information and parameters become available after an accident, enabling more accurate consequence analysis. This implies that the results of consequence analysis based on this detailed information provide more realistic results than those based on assumed accidents. This study attempts to optimize the resource allocation and cost-effectiveness of emergency response plans for chemical accidents. Existing procedures and manuals are revised to elucidate the proposed model and conduct real-time consequence analysis. The existing emergency response plan is compared to verify the proposed model's efficacy. The obtained results indicate that the proposed model can exhibit better performance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.1-11
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• 2016

The domestic and foreign seismic design codes have specified that time history covers design response spectrum when the response spectrum, which calculated from the time history, is smaller than the design response spectrum at five points or less. In order to verify the design codes, time history analysis for a pier was performed by using five artificial time histories conforming design code with various characteristics and its member forces were evaluated according to them. It was confirmed from analysis results that, regardless of the conformity to design code requirement, seismic design using the artificial time histories could not guarantee earthquake resistant design if the response spectrum from them is lower than design response spectrum at the similar period to the natural frequency of structure. Thus, the time history generating method to make its acceleration response spectrum to be greater than design response spectrum at all period was proposed by two modification function in this study. It was also verified whether time histories from the proposed method satisfy the seismic design codes or not.