• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.111-112
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• 2010

This study proposes a new methodology of earthquake damage evaluation for R/C Buildings combined with shear and flexural failure systems, based on non-linear required strength spectrum. Part I shows a concept of methodology of earthquake damage evaluation, which is estimated on the basis of system ductility, non-linear required strength spectrum and remaining seismic capacity ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.113-114
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• 2010

In this study, the earthquake damage evaluation of a R/C frame building is carried out based on the method proposed in Part I. Using the proposed method, the earthquake damage of building system based on non-linear required strength spectrum can be effectively evaluated without using the detailed seismic evaluation methods, including non-linear dynamic analyses, capacity spectrum method, etc.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.67-70
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• 1999

DS-CDMA is used to widely spread spectrum for a cellular mobile digital communication that maximizing users- capacity at the limited frequency bandwidth, solving technical matters with the channel. Especially, the capability of a spread spectrum receiver relied on fast code acquisition time at the demodulation. In this paper, we considered that fast code acquisition time when a spread spectrum system is designed, and existed code acquisition system set up one code epoch on a position at initial processing, but the proposed code acquisition system improved that two code epoch are set up at the same time, therefore code acquisition time is diminished in effect. The structure modeling to VHDL language. Its synthesized the synthesized and, is implemented FPGA chip

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.258-265
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• 2002

Most structures are expected deform nonlinear and inelastic behavior when subjected to strong ground motion. Nonlinear time history analysis(NTHA) is the most rigorous procedure to compute seismic performance in the various inelastic analysis methods. But nonlinear analysis procedures necessitate more reliable and practical tools for predicting seismic behavior of structures. Some building codes propose the capacity spectrum method. This method is the concept of an equivalent linear system, wherein a linear system having reduced stiffness and increased damping is used to estimate the response of the nonlinear system. This procedure are conceptually simple, but the iterative procedure is time-consuming and may sometimes lead to no solution or multiple solutions. This paper presents a nonlinear direct spectrum method(NDSM) to evaluate seismic performance of structures, without iterative computations, given by the structural initial elastic period and yield strength from the pushover analysis, especially for mixed building structure.

• Annual Conference of KIPS
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• 2005.11a
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• pp.1279-1282
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• 2005

본 논문은 초고속 전송을 위해 설계된 HCOC(High Capacity Orthogonal Code) 기술을 적용한 Multi-Code Spread Spectrum System에서 발생할 수 있는 PAPR(Peck to Average power Ratio) 문제해결을 위한 연구이다. H(HCOC)MC-SS 시스템의 PAPR 감소를 위해 기본적인 SLM(Selected Mapping) 기법을 적용하였으며, 또한 SLM 기법의 단점인 많은 계산량 감소를 위해 Recursive 방법을 적용한 Recursive SLM HMC-SS 시스템을 제안하였다. 컴퓨터 시뮬레이션을 통해 제안하는 시스템을 검증하였으며, 또한 초고속 전송을 위한 16 QAM-SS 시스템과 $4{\times}4$ HMC-SS 시스템의 성능을 비교 분석하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.53-60
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• 2002

It has been recognized that damage control must become a more explicit design consideration. In an effort to develop design methods based on performance it is clear that the evaluation of the inelastic response is required. The methods available to the design engineer today are nonlinear time history analyses, or monotonic static nonlinear analyses, or equivalent static analyses with simulated inelastic influences. Some codes proposed the capacity spectrum method based on the nonlinear static(pushover) analysis to determine earthquake-induced demand given the structure pushover curve. This procedure is conceptually simple but iterative and time consuming with some errors. This paper presents a nonlinear direct spectrum method to evaluate seismic Performance of structure, without iterative computations, given the structural initial elastic period and yield strength from the pushover analysis, especially for multi degree of freedom structures. The purpose of this paper is to investigate accuracy and confidence of this method from a point of view of various earthquakes and unloading stiffness degradation parameters.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.1
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• pp.17-26
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• 2009

The capacity spectrum method (CSM), which is known to be an approximate technique for assessing the seismic capacity of an existing structure, was originally proposed for simple building structures that could be modeled as single-degree-of-freedom (SDOF) systems. More recently, however, CSM has increasingly been adopted for assessing most bridge structures, as it has many practical advantages. Some studies on this topic are now being performed, and a few results of these have been presented as ground-breaking research. However, studies have until now been limited to symmetrical straight bridges only. This study evaluates the practical applicability of CSM to the evaluation of irregular curved bridges. For this purpose, the seismic capacities of 3-span prestressed concrete bridges with different subtended angles subjected to some recorded earthquakes are compared with a more refined approach based on nonlinear time history analysis. The results of the study show that when used for curved bridges, CSM induces higher inelastic displacement responses than the actual values, and that the gap between the two becomes larger as the subtended angle increases.

• Earthquakes and Structures
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• v.2 no.1
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• pp.25-42
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• 2011

This paper discusses a mechanical model for the vulnerability assessment of old masonry building aggregates that takes into account the uncertainties inherent to the building parameters, to the seismic demand and to the model error. The structural capacity is represented as an analytical function of a selected number of geometrical and mechanical parameters. Applying a suitable procedure for the uncertainty propagation, the statistical moments of the capacity curve are obtained as a function of the statistical moments of the input parameters, showing the role of each one in the overall capacity definition. The seismic demand is represented by response spectra; vulnerability analysis is carried out with respect to a certain number of random limit states. Fragility curves are derived taking into account the uncertainties of each quantity involved.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.172-179
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• 2003

In the performance based seismic design method such as the capacity spectrum method, it is required to estimate precisely strength, deformability and energy dissipation of the member. However it merely depends on empirical equations which are not exact in the estimation of energy dissipation capacity. It is same to the generously used computer programs for nonlinear analysis such as DRAIN-2DX. On the other hand, simple equations for evaluating energy dissipation were developed in a recent study, In this paper, based on the evaluation method, a new cyclic behavior model for a flexure-dominated RC member is proposed. Although this model is simplified, it can accurately reflect the variation of energy dissipation capacity with design parameters. Using this model, a program for the nonlinear static/dynamic analysis of RC moment frame structures is also developed.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.13-20
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• 2006

In cellular mobile communications, how to achieve optimum system capacity with limited frequency spectrum is one of the main research issues. Many dynamic channel assignment (DCA) schemes have been proposed and studied to allocate the channels more efficiently, thus, the capacity of cellular systems is improved. Reuse partitioning (RP) is another technique to achieve higher capacity by reducing the overall reuse distance. In this paper, we present a network-based DCA scheme with the implementation of RP technique, namely dynamic reuse partitioning with interference information (DRP-WI). The scheme aims to minimize the effect of assigned channels on the availability of channels for use in the interfering cells and to reduce their overall reuse distances. The performance of DRP-WI is measured in terms of blocking probability and system capacity. Simulation results have confirmed the effectiveness of DRP-WI scheme. Under both uniform and non-uniform traffic distributions, DRP-WI exhibits outstanding performance in improving the system capacity. It can provide about 100% capacity improvement as compared to conventional fixed channel assignment scheme with 70 system channels.