• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2188-2191
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• 2005

We consider a fault detection and isolation problem for inertial navigation systems which use redundant inertial sensors. We propose a FDI method using average of multiple parity vectors which reduce false alarm and wrong isolation, and improve correct isolation. We suggest the number of redundant sensors required to isolate simultaneous faults. The performance of the proposed FDI algorithm is analyzed by Monte-Carlo simulation.

• 제어로봇시스템학회논문지
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• 제4권6호
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• pp.695-702
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• 1998

In this paper, we propose a novel fault isolation filter design method using the left eigenstructure assignment scheme proposed by Choi et. al., The proposed filter shows good fault isolation performance with exact eigenstructure assignment. An eigenstructure assignment methodology which satisfies the required fault isolation conditions is also proposed. The proposed method guarantees that the corrupted m simultaneous faults can be isolated when the number of available output measurements are (m+1).

• 전산구조공학
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• 제4권4호
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• pp.107-116
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• 1991

Base isolation is the alternative tool to protect structures against the earthquake. Basic ideas are the flexibflity to reduce the response of the structure, energy dissipation to reduce the excessive deflection by flexibility, and the rigidity under the service load. Base isolation is specially good for bridges because it can be installed easily and be used for both new construction and rehabilitation. This paper describes the basic ideas of base isolation, various base isolation devices and design guidelines by AASHTO. It also introduces the applications in United States and New Zealand.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.1115-1121
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• 2003

The vibration isolation table system for the high precision Processing machinery has been developed. The system uses air spring as its isolation elements. An investigation of the model and the test results showed that the diaphragm has a role in the mathematical model. The vibration levels at various floors in the laboratory were investigated during operating the large shaking table for the selection of optimum installation location. The vibration test on the designed system showed good isolation performances.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.135-136
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• 2011

• Earthquakes and Structures
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• 제4권4호
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• pp.341-363
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• 2013

Earthquake response calculation, parametric analysis and seismic parameter optimization of base-isolated structures are some critical issues for seismic design of base-isolated structures. To calculate the earthquake responses for such non-symmetric and non-classical damping linear systems and to implement the earthquake resistant design codes, a modified complex mode superposition design response spectrum method is put forward. Furthermore, to do parameter optimization for base-isolation structures, a graphical approach is proposed by analyzing the relationship between the base shear ratio of a seismic base-isolation floor to non-seismic base-isolation one and frequency ratio-damping ratio, as well as the relationship between the seismic base-isolation floor displacement and frequency ratio-damping ratio. In addition, the influences of mode number and site classification on the seismic base-isolation structure and corresponding optimum parameters are investigated. It is demonstrated that the modified complex mode superposition design response spectrum method is more precise and more convenient to engineering applications for utilizing the damping reduction factors and the design response spectrum, and the proposed graphical approach for parameter optimization of seismic base-isolation structures is compendious and feasible.

• Smart Structures and Systems
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• 제8권4호
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• pp.399-412
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• 2011

This study compares the performance of two smart isolation systems that utilize superelastic shape memory alloys (SMAs) for seismic protection of bridges using energy balance concepts. The first isolation system is a SMA/rubber-based isolation system (SRB-IS) and consists of a laminated rubber bearing that decouples the superstructure from the bridge piers and a SMA device that provides additional energy dissipation and re-centering capacity. The second isolation system, named as superelastic-friction base isolator (S-FBI), combines the superelastic SMAs with a flat steel-Teflon bearing rather than a laminated rubber bearing. Seismic energy equations of a bridge structure with SMA-based isolation systems are established by absolute and relative energy balance formulations. Nonlinear time history analyses are performed in order to assess the effectiveness of the isolation systems and to compare their performance. The program RSPMatch 2005 is employed to generate spectrum compatible ground motions that are used in time history analyses of the isolated bridge. Results indicate that SRB-IS produces higher seismic input energy, recoverable energy and base shears as compared to the S-FBI system. Also, it is shown that combining superelastic SMAs with a sliding bearing rather than rubber bearing significantly reduce the amount of the required SMA material.

• 한국지진공학회논문집
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• 제21권3호
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• pp.125-135
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• 2017

Various seismic isolation methods are being applied to bridges and buildings to improve their seismic performance. Most seismic isolation systems are the structural seismic isolation systems. In this study, the seismic performance of geotechnical seismic isolation system capable of isolating the lower foundation of the bridge structure from ground was evaluated. The geotechnical seismic isolation system was built with teflon, and the model structure was made by adopting the similitude law. The response acceleration for sinusoidal waves of various amplitudes and frequencies and seismic waves were analyzed by performing 1-G shaking table experiments. Fixed foundation, Sliding foundation, and Rocking foundation were evaluated. The results of this study indicated that the Teflon-type seismic foundation isolation system is effective in reducing the acceleration transmitted to the superstructure subject to large input ground motion. Response spectrum of the Rocking and Sliding foundation structures moves to the long period, while that of Fixed foundation moves to short period.

• 대한전자공학회논문지TC
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• 제48권2호
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• pp.79-84
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• 2011

본 논문에서는 아이솔레이션 에이드를 사용하여 격리도를 향상시킨 무선랜용 MIMO안테나를 설계하였다. IEEE 802.11.n의 무선랜대역인 2.4GHz대역과 5GHz대역에서 사용이 가능한 PIFA를 안테나 프레임과 접지면을 기준으로 대칭으로 배치하였다. 두 안테나 사이에 아이솔레이션 에이드를 삽입하여 2.4GHz대역의 격리도를 최대 5dB향상시켰고, 5GHz대역의 격리도를 최대 7dB향상 시켰다. 제안된 안테나의 전체효율은 60%이상이며, 계산된 ECC(Envelope Correlation Coefficient)는 0.1이하이다.

• Earthquakes and Structures
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• 제12권3호
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• pp.285-296
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• 2017

Base isolation is a quite practical control strategy for enhancing the response of structural systems induced by strong ground motions. Due to the dynamic effects of base isolation systems, reduction in the interstory drifts of the superstructure is often achieved at the expense of high base displacement level, which may lead to instability of the structure or non-practical designs for the base isolators. To reduce the base displacement, several hybrid structural control strategies have been studied over the past decades. This study investigates a particular strategy that employs Tuned Mass Dampers (TMDs) for improving the performance of base-isolated structures and unlike previous studies, specifically focuses on the effectiveness of this hybrid control strategy in structures that are equipped with nonlinear base isolation systems. To consider the nonlinearities of base isolation systems, a Bouc-Wen model is selected and nonlinear dynamic OpenSees models are used to perform several time-history simulations in time and frequency domains. Through these numerical simulations, the effects of several parameters such as the fundamental period of the structure, dynamic properties of the TMD and isolation systems and properties of the input ground motion on the behaviour of TMD-structure-base isolation systems are examined. The results of this study provide a better insight into the performance of linear shear-story structures with nonlinear base isolators and show that there are many scenarios in which TMDs can still improve the performance of these systems.