• Structural Engineering and Mechanics
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• v.12 no.1
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• pp.51-69
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• 2001

Whereas the potential of static inelastic analysis methods is recognised in earthquake design and assessment, especially in contrast with elastic analysis under scaled forces, they have inherent shortcomings. In this paper, critical issues in the application of inelastic static (pushover) analysis are discussed and their effect on the obtained results appraised. Areas of possible developments that would render the method more applicable to the prediction of dynamic response are explored. New developments towards a fully adaptive pushover method accounting for spread of inelasticity, geometric nonlinearity, full multi-modal, spectral amplification and period elongation, within a framework of fibre modelling of materials, are discussed and preliminary results are given. These developments lead to static analysis results that are closer than ever to inelastic time-history analysis. It is concluded that there is great scope for improvements of this simple and powerful technique that would increase confidence in its employment as the primary tool for seismic analysis in practice.

• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.160-163
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• 2012

시간관리는 자기조절관리의 중요한 요인으로 자리매김하면서 중요한 학습전략으로 채택되고 있다. 이에 따라, 최근까지 웹이나 스마트폰에서 시간을 관리하는 응용들이 많이 개발되고 있다. 하지만, 기존의 프로그램들을 본다면 현재와 과거를 기록하는 형식이 주를 이루었고 시간이 중심이었지 이를 공간과 함께 고려하지는 않았다. 하지만 본 연구는 웹을 기반으로 하여 시간과 공간을 함께 고려한 사용자 히스토리 기록과 미래를 설계할 수 있는 응용 프로그램을 개발한다. 본 연구에서는 미래도 함께 계획할 수 있게 구성되었고 시간과 함께 공간도 기록할 수 있다는 점에서 다른 기존의 프로그램 차별화를 이룬다. 또한, 학생들이 미래를 계획할 때 부모가 일방적으로 지도하는 것이 아니라 조언자로서의 역할을 하여 학생들과 상호작용을 할 수 있는 장점을 가진다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.379-386
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• 2001

Fluid viscous dampers have been used as energy dissipators or STU's (Shock Transmission Unit) in earthquake resistant designs for bridges. Viscous dampers have many advantages compared to other friction type or visco-elastic type of dampers. They do neither increase internal pier forces due to their out of phase response, nor produce reaction forces at the low velocities associated with thermal movements. Therefore, they anable the super structure to restore itself perfectly after a severe movement dut to seismic excitations. This paper investigates the response of bridges designed with viscous dampers in regard to damping coefficients, properties of dampers, and arrangements of dampers. For this purpose, time-history dynamic analyses have been performed using a very simple model relevant to a typical bridge example. Based on the results, it presents some design duidelines on how to determine a proper damping ratio and on how to arrange dampers. In usual cases, damping coefficients corresponding to about 0.2-0.3 of damping ratios seem to be very effective in bridge designs.

• Smart Structures and Systems
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• v.17 no.5
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• pp.709-724
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• 2016

This study investigates the optimum design parameters of a superelastic friction base isolator (S-FBI) system through a multi-objective genetic algorithm to improve the performance of isolated buildings against near-fault earthquakes. The S-FBI system consists of a flat steel-PTFE sliding bearing and superelastic NiTi shape memory alloy (SMA) cables. Sliding bearing limits the transfer of shear across the isolation interface and provides damping from sliding friction. SMA cables provide restoring force capability to the isolation system together with additional damping characteristics. A three-story building is modeled with S-FBI isolation system. Multiple-objective numerical optimization that simultaneously minimizes isolation-level displacements and superstructure response is carried out with a genetic algorithm in order to optimize S-FBI system. Nonlinear time history analyses of the building with optimal S-FBI system are performed. A set of 20 near-fault ground motion records are used in numerical simulations. Results show that S-FBI system successfully control response of the buildings against near-fault earthquakes without sacrificing in isolation efficacy and producing large isolation-level deformations.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.63-68
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• 2000

Concrete is popular as a building material, however it is inherently brittle and performs poorly during earthquakes if nor reinforced properly. Traditional retrofit design techniques assume that buildings respond elastically to earthquakes. This assumption simplifies the analysis procedure but can lead to an erroneous conclusion. The complete nonlinear time history analysis is considered overly complex and impractical for general use. Simplified nonlinear analysis methods, referred to as nonlinear static analysis procedures, include the capacity spectrum method(CSM) developed in detail at ATC-40 and the displacement coefficient method(DCM) utilized at FEMA-273. In this study wall APT system. The results were compared and analyzed. The program used was neaMAX-3D to express nonlinear material.

• Structural Engineering and Mechanics
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• v.3 no.6
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• pp.569-581
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• 1995

In this paper, the seismic behavior of a 10-story building equipped with viscoelastic dampers is analyzed. The effects of ambient temperature, the thickness, the total area, and the position of the viscoelastic dampers are studied. Results indicate that the energy-absorbing capacity of viscoelastic damper decreases with increasing the ambient temperature. The thickness and the total area of viscoelastic dampers also affect the seismic mitigation capacity. The thickness cannot be too small, which is not effective in vibration reduction, nor can it be too large, which not only increases the cost but also reduces the seismic resistance. The total area of viscoelastic dampers should be determined properly for optimum damper performance at the most economical design. The mounting position of viscoelastic dampers also influences the structure's seismic performance. Numerical results show that, if properly equipped, the VE dampers can reduce the structural response both floor displacement and story shear force and increase the overall level of damping in structures during earthquakes.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.411-418
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• 2003

In order to retrofit R/C frame structures, a newly proposed Teflon sliding wall damper, consisted of Teflon slider and R/C shear wall, is evaluated by the dynamic analysis model of inelastic frame structures. From analysis results, it is shown that the damper reduces the time-history responses, the maximum story drifts, and the damage of R/C member. By control of damper pressures, especially, the damper can be easily applicable not only to capacity design according to required responses and member damages but also to active damper with actively controlling devices.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.379-386
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• 2002

The objective of this study is to investigate the seismic demand on the isolated slab-on-steel girder bridge under cold climate conditions. To this end comparative test results are presented of laminated elastomeric and lead-rubber seismic isolators in warm and cold temperature conditions. At extremely cold temperatures, rubber "glass-harden" and as a result rubber bearings that may be used for seating bridges behave in a significantly non-linear fashion. From the nonlinear time history analysis of the isolated slab-on-steel girder bridge, larger forces are transferred to the substructures. however smaller displacement at superstructure is obtained under cold climate conditions. These phenomenons might need to be considered in design stage of the seismically isolated bridges.

• Korean Journal of Mathematics
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• v.20 no.4
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• pp.493-505
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• 2012

For the first time ever in its history, the United States has a national version for K-12 mathematics programs, the Com-mon Core State Standards for Mathematics. Since its final version appeared in 2010 in the United States, the Common Core State Standards have started getting much attention from the Korean mathematics and mathematics education communities. Although attempts have been made to translate the original text of the stan-dards, the information such as the paradigm shift that led to the development of the standards, design principles and a comparison with the NCTM Standards would aid understating the standards in the intended way and avoiding unnecessary confusion.

• Journal of the Korean Society of Costume
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• v.20
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• pp.179-190
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• 1993

In the history of fashion, few designers have interpreted the background of the time more accurately and energetically than did Elsa Schiaparelli. She understood the new role of women and believed clothes should suit one's life style. Schiaparelli begun with sportswear, later included suits and dresses. She produced them of great elegance and extreme chic. Simplicity of line was the key to her distinctive and elegant silhouette. Even her simplest designs had elegance. Her concept of clothes was architectual : the more the plane of the body were respected, the more the garment acquired vitality. Schiaparelli combined her knowledge, timing, and sense of daring in the presentation of her designs, colors, fabrics, and embroideries. For V, the garment was not only the medium for the couturier's craft but also the place for artistic expression. Her self-conscious equation of designer's objectives with that of artist is at the heart of her work. Schiaparelli's work is an expression of desire, not merely of design.