• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.625-635
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• 1997

The base isolation technique and its benefits in reducing the transmitted earthquake energy into a structure have gained increasing recognition during the last two decades. Unfortunately, the current available design procedures, especially for base-isolated bridges, seem inadequate and too restrictive. As a result, practical design procedure still relies upon a series of deterministic time history analyses. In this study, the evaluation of the possibility of the normal mode method to predict the nonlinear seismic responses of base isolated bridges has been performed. The applicability has been examined through the numerical approach with isolator's elastic or plastic states of the base isolated bridges. Numerical results show that the 1st. mode period and the various responses are varied with the state but are conversed. And, the result show that the normal mode method is applicable to predict the seismic responses and to design the babe isolated bridge. Various analysis method to bridges with bilinearized hysteresis isolator and various pier heights are evalulated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.85-93
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• 1993

Base isolation systems are economic and efficient for the control of structural vibration. In this study, the base isolators of LRB(laminated rubber bearing) type which have been generally used are fabricated and tested. From the static and dynamic tests, the characteristics of the base isolators, considering strain-hardening, hysteretic damping and horizontal stiffnesses, etc., are verified and particularly the feasibility as base isolation devices is discussed. Consequently, the test results are compared with the analytical ones that are derived from idealization as a bilinear model.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.637-647
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• 1997

As stated in Part(I), the use of the isolator is meant to protect a structure from seismic risk, by concentrating the inelastic deformations to relatively cheap and replaceable devices while the rest of the structures remains elastic. This research has been carried out to investigate the effects of various structural parameters and isolator characteristics on the seismic response of Base Isolated Bridges. Simplified analysis method for practical design is developed by using the results. The Proposed Code-Type approach method can be used to estimate the inertial forces accurately, not only at the isolator but throughout the height of the Base-Isolated Bridges. The proposed method is recommended to use in preliminary design tool or even a final design tool for Base Isolated Bridges. For the validation of simplified design method, examples with artificial earthquake time history and design response spectrum for P.C Box Bridge with bilinear hysteretic steel damper are evaluated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.13-18
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• 1993

The purpose of this study is to analyze the seismic effects of Lead Rubber Bearing base isolators on bridges. Base isolation is the tool to minimize the effect of earthquake before the seismic force is transfered to the structure. Currently, many structures including the buildings, power plants, and bridges, were built and planned with base isolation method. The simple model is developed for bridges with Lead Rubber Bearings. Equations of motion are solved by Newmark ${\beta}$ method. Springs representing the base isolators are assumed as bilinear springs and piers are modeled as nonlinear springs implementing Q-HYST model. Analysis is performed for the selected bridge. El Centro (N-S) earthquake(1940) is used. Deck displacement, pier ductility and pier shear force are calculated for the various Lead Rubber Bearings.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.2
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• pp.39-48
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• 1997

New form of base isolators made of steel spring coated with both natural and artficial rubber were manufactured and tested for material properties. Shaking table experiments were performed using a model structure attached with the bearings. The model structure used in the test is a 1/4 scaled steel structure, and earthquake records were used to check the lateral and vertical stability and effectiveness of the isolators. According to the results all three types of isolators turned out to be effective in reducing the acceleration induced by the earthquake vibration.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.91-98
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• 2021

The installation and performance test of the ISOL (Isotope Separation On Line) system for the generation and separation of Rare Isotopes (RI) beams is in progress at the Rare Isotope Science Project (RISP), Institute for Basic Science (IBS). The various RI beams generated by the ISOL target/ion source go through the beam lines and separators, and only the RI beam desired by the user is selected and transmitted to the superconducting linear accelerator at the downstream of the ISOL. In the ISOL system, two separators are installed to separate a specific RI beam, and control is performed by the Experimental Physics and Industrial Control System (EPICS). In this study, an EPICS IOC (Input-Output Control) was developed to measure the magnetic field of a dipole magnet for mass separation of a multivalent (n+) RI beam in the A/Q separator, which is one of the ISOL RI beam separators. The operational stability of the A/Q separator was tested through a magnetic field measurement using a Hall probe.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.874-876
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• 2002

의무분리 정책의 목적은 정보의 무결성을 필요로 하는 연산들을 여러 역할이나 사용자에게 분산시킴으로써 조직 내에서 관리하는 정보의 무결성 침해 가능성을 최소화하는 것이며, 이는 기업 환경에서 중요한 보안 요구사항이다. 역할기반 접근제어는 응용에 따라 보호 객체들에 대한 역할들로 분류하여 단순한 권한 관리를 제공하며 ,의무분리 정책을 시행하기에 적합하여 기존의 강제적 접근제어나 임의적 접근제어에 대한 대안으로 의무분리와 관련하여 다양한 기법들이 제시되었다. 그러나 역할 수준의 의무분리는 역할에 할당된 과업들을 상호 배타적인 작업의 수행에 관련되지 않은 과업도 모두 배제시키게 되어 과업 실행의 유연성이 떨어지게 되므로 상호 배타적인 작인을 수행하는 과업들에 할당된 최소의 권한을 배제시키는 것이 합리적이다. 본 논문은 기업 환경에 적합한 과업-역할기반 접근제어 모델을 기초로 하여 과업의 특성에 따라 분류된 유형별로 과업 수준의 동적 의무분리를 적용하는 기법을 제시한다. 특히 실제 사용자가 병렬적으로 수행하는 워크플로우와 다중 세션 환경에서 상호 배타적인 과업들과 과업 인스턴스들에도 적용이 가능만 세션기반의 동적 의무분리 기법을 제시한다 이때 기존의 동일 사용자에 의한 동적 의무분리 적용을 공모가 가능한 사용자들에 의해 생성된 다중 세션들간의 동적 의무분리를 제시함으로써 의무분리의 목적을 만족시킨다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.1
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• pp.19-28
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• 2016

In the case of structural analysis for building structures, the super-structure and the sub-structure are analyzed by using separate structural models in the field because of time saving, facile result interpretation and easy analysis of dynamic behavior. However this separate structural model violated the compatibility condition of structural analysis and it can not consider the interaction of superand sub- structures. In the present study, the analysis results of this separate model were compared to those of the unified model of super- and sub- structures which can consider the interaction of super- and sub- structures and reflect the realistic boundary conditions. According to the comparison results, the the analysis model using separate models can underestimate the member force and deflection of structural members in the super-structures and overestimate the deflection and member force of sub-structures. Therefore, in the case of high-rise buildings, irregular shaped buildings, buildings which are expected to be affected by large differential settlement and remodeling buildings, the unified structural model for super- and sub- structures was recommended for structural analysis instead of the separate structural model.

• 레미콘
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• no.10 s.69
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• pp.19-26
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• 2001

• Computational Structural Engineering
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• v.7 no.4
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• pp.145-150
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• 1994

Seismic isolation in ordinary buildings has been successively adapted to provide flexibility for the reduction of base shear forces and its concept is accepting wide agreement in lengthening the natural, period to lessen the spectral acceleration transmitted into the structure. However, one of difficulties in implementing the innovative concept to nuclear structures is due to more severe requirements in both understanding and predicting the characteristics of isolators and the behavior of cushioned structures, Stochastic analysis has been carried out to investigate the response of base isolated nuclear containers to the random earthquake ground motion.