• Journal of Industrial Technology
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• v.25 no.A
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• pp.15-22
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• 2005

In order to evaluate seismic performance of multi-degree-of-freedom bridge structure, moderate lateral load distribution methods using the pushover analysis were developed by many researchers. One of important variables to improve an accuracy of pushover analysis is lateral load distribution. In this study, pushover analyses were performed using the five types of lateral load distribution and seismic performances were evaluated by capacity spectrum method (CSM). To verify an accuracy of suggested lateral load distribution, the maximum displacement estimates by the CSM were compared to those by inelastic time history analysis.

• Structural Engineering and Mechanics
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• v.36 no.3
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• pp.321-341
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• 2010

The seismic-induced failure of a dam could have catastrophic consequences associated with the sudden release of the impounded reservoir. Depending on the severity of the seismic hazard, the characteristics and size of the dam-reservoir system, preventing such a failure scenario could be a problem of critical importance. In many cases, the release of water is controlled through a reinforced-concrete intake tower. This paper describes the application of a static nonlinear procedure known as the Capacity Spectrum Method (CSM) to evaluate the structural integrity of intake towers subject to seismic ground motion. Three variants of the CSM are considered: a multimodal pushover scheme, which uses the idea proposed by Chopra and Goel (2002); an adaptive pushover variant, in which the change in the stiffness of the structure is considered; and a combination of both approaches. The effects caused by the water surrounding the intake tower, as well as any water contained inside the hollow structure, are accounted for by added hydrodynamic masses. A typical structure is used as a case study, and the accuracy of the CSM analyses is assessed with time history analyses performed using commercial and structural analysis programs developed in Matlab.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.2
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• pp.35-44
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• 2004

In the capacity spectrum method(CSM) using a linear response spectrum, the peak response of an inelastic system under a given earthquake load is estimated transforming the system into the equivalent elastic one. The CSM for estimating the peak inelastic response is evaluated in this paper. The equivalent period and damping ratio are calculated using the ATC-40, G lkan, Kowalsky, and Iwan methods, and the performance points are obtained according to the procedure B of ATC-40. Analysis results indicate that the ATC-40 method generally underestimates the peak response resulting in the unsafe design, while the G lkan and Kowalsky methods overestimate the responses. The Iwan method produces the values between those by the ATC-40 method and the G lkan and Kowalsky methods, and estimates the responses relatively closer to the exact ones. Further, it is found that the Kowalsky method gives the negative equivalent damping ratios depending on the hardening ratios, and thereby can not be used to estimate the responses in some cases.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.39-44
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• 2010

In this paper, we derive the channel capacity in order to transmit an additional data by using digital watermarking method in generalized-K fading channel. Spread spectrum watermarking is one of the digital watermarking methods which is the most promising technique due to it's very robustness to the channel noise and easy achieving of the signal detection by correlators at the receiver. It is important to analyze the channel capacity to transmit an additional data through wireless channel because the transmitted data would be affected by the channel fading effects. From the results, we confirm that the channel capacity of the SSW system can be determined by the HWR, WNR, PN length and host sampling frequency. Also, we verified that the level of HWR and WNR can be determined by the derived capacity formula. The results of this paper can be applied to general spread spectrum watermarking system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.6
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• pp.453-460
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• 1988

The error probability for coherent frequency-hopped spread-spectrum multiple-access communications is computed by using characteristic function method. We employ PSK as a modulation scheme. The channel capacity is performance measure and the minimum bit signal-to-noise ratio for reliable communications is obtained.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.119-126
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• 2006

Capacity spectrum method(CSM) of ATC-40(1996) and displacement coefficient method(DCM)of FEMA-273(1997) are applied to evaluate the seismic performance of bridges. In this study, equivalent response is obtained from nonlinear static analysis for the 3spans continues bridge and nonlinear maximum displacement response is calculated using CSM and DCM. Nonlinear maximum displacement response of DCM is larger than this of CSM. It is method that DCM can evaluate target displacement and ductility of structural to be easy and simple, but tend to overestimate the maximum displacement response. Therefore, this method is mainly used at preparation design level to evaluate the structural response. It is not desirable to evaluate the seismic performance using DCM.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.569-576
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• 2001

In this study a procedure for evaluation of performance point using direct displacement-based design method was developed to enhance the applicability of the method. Parametric study has been performed for the natural period of the structure, yield strength, and the stiffness after the first yield. The proposed method was also applied to a 10-story steel frame. To verify the accuracy of the result, the results from capacity spectrum analysis and time history analysis were compared. The results of the proposed method turned out to match well with the results of capacity spectrum method and the time history analysis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.247-257
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• 2002

Recently, performance-based analysis/design methods such as the capacity spectrum method and the direct displacement-based design method were developed. In these methods, the estimation of energy dissipation capacity due to inelastic behavior of RC structures depends on empirical equations which are not sufficiently accurate. On the other hand, in a recent study, a simplified method for evaluating energy dissipation capacity was developed. In the present study, based on the evaluation method, a new seismic design method for flexure-dominated RC walls is developed. In determination of seismic earthquake load, the proposed design method can address variation of the energy dissipation capacity with design parameters such as dimensions and shapes of cross-sections, axial force, and reinforcement ratio and arrangement. The proposed design method is compared with the current performance-based design methods and the applicability of the proposed method is disscussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.730-736
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• 2016

In a previous study, the impact factor response spectrum and corresponding method for evaluating the load carrying capacity of bridges was suggested to improve the existing evaluation method. To verify the applicability of the suggested method, which is based on the frequency of bridges, the dynamic characteristic test for an actual single span simply-supported bridge was conducted. Through a field test under ambient traffic conditions, the dynamic response of the bridge was obtained using wireless accelometers and its fundamental frequency was identified. The peak impact factor was determined from the identified frequency and the impact factor response spectrum. The load carrying performance variation of the bridge was estimated considering the performance reduction factor, which was calculated using the current and previous natural frequency and impact factor. From the result, the load carrying capacity of the bridge was decreased, but the capacity was still enough because its value is greater than the design live load. Through the overall procedures and technical details presented in this paper, the suggested evaluation method can be applied to actual bridges with the acceleration data measured under ambient traffic conditions and the impact factor response spectrum.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1220-1226
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• 2011

The purpose of this study is to assess the seismic performance of a reinforced concrete pier using ductility demand-based seismic design method and nonlinear earthquake analysis. A computer program named MIDAS/Civil(MIDAS IT,2009) for the analysis of the reinforced concrete pier was used. The bridge pier was designed by the ductility demand-based seismic design. In addition, a seismic performance was evaluated through both capacity spectrum method and nonlinear time history method. In order to determine the seismic performance of the bridge pier, the maximum response values from the capacity spectrum method and nonlinear time history analysis were compared each other.