• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.448-453
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• 2001

This paper presents an analytical evaluation of the effect of motion on seismic responses of base isolated low-level building and experimental studies to evaluate isolation performances of a rubber bearing. Dynamic responses induced by earthquake were evaluated by response analyses, taking the rubber bearing of the base isolation devices into account. In the experiment, vibration tests were carried out using a model for rubber bearings as isolation devices against earthquake in order to investigate the isolation performances of the rubber bearings. Several kinds of rubber bearing for base isolated low-level building against earthquake are examined. As a result, it is shown that the effect of the motion on the response of the building and the base response is well controlled from a seismic design standpoint.

• International Journal of Concrete Structures and Materials
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• 제9권4호
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• pp.439-451
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• 2015

This study analyzed the isolation effect for a 15-story reinforced concrete (RC) building with regard to changes in the beam-column stiffness ratio and the difference in the vibration period between the superstructure and an isolation layer in order to provide basic data that are needed to devise a framework for the design of isolated RC buildings. First, this analytical study proposes to design RC building frames by securing an isolation period that is at least 2.5 times longer than the natural vibration period of a superstructure and configuring a target isolation period that is 3.0 s or longer. To verify the proposed plan, shaking table tests were conducted on a scaled-down model of 15-story RC building installed with laminated rubber bearings. The experimental results indicate that the tested isolated structure, which complied with the proposed conditions, exhibited an almost constant response distribution, verifying that the behavior of the structure improved in terms of usability. The RC building's response to inter-story drift (which causes structural damage) was reduced by about one-third that of a non-isolated structure, thereby confirming that the safety of such a superstructure can be achieved through the building's improved seismic performance.

• Journal of Electrical Engineering and Technology
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• 제7권3호
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• pp.411-419
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• 2012

This paper proposes a new FDI(Fault Detection and Isolation) method, which is called EPSA(Extended Parity Space Approach). This method is particularly suitable for fault detection and isolation of the system with one faulty sensor or two faulty sensors. In the system with two faulty sensors, the fault detection and isolation probability may be decreased when two faults are occurred between the sensors related to the large fault direction angle. Nonetheless, the previously suggested FDI methods to treat the two-faults problem do not consider the effect of the large fault direction angle. In order to solve this problem, this paper analyzes the effect of the large fault direction angle and proposes how to increase the fault detection and isolation probability. For the increase the detection probability, this paper additionally considers the fault type that is not detected because of the cancellation of the fault biases by the large fault direction angle. Also for the increase the isolation probability, this paper suggests the additional isolation procedure in case of two-faults. EPSA helps that the user can know the exact fault situation. The proposed FDI method is verified through Monte Carlo simulation.

• Earthquakes and Structures
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• 제9권3호
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• pp.639-656
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• 2015

Seismic isolation devices are commonly used to mitigate damages caused by seismic responses of structures. More damages are created due to progressive collapse in structures. Therefore, evaluating the impact of the isolation systems to enhance progressive collapse-resisting capacity is very important. In this study, the effect of lead rubber bearing isolation system to increase the resistance of structures against progressive collapse was evaluated. Concrete moment resisting frames were used in both the fixed and base-isolated model structures. Then, progressive collapse-resisting capacity of frames was investigated using the push down nonlinear static analysis under gravity loads that specified in GSA guideline. Nonlinear dynamic analysis was performed to consider dynamic effects column removal under earthquake. The results of the push down analysis are highly dependent on location of removal column and floor number of buildings. Also, seismic isolation system does not play an effective role in increasing the progressive collapse-resisting capacities of structures under gravity loads. Base isolation helps to localize failures and prevented from spreading it to intact span under seismic loads.

• 가정과삶의질연구
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• 제26권5호
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• pp.91-107
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• 2008

This study investigated the isolation hypothesis and the buffer hypothesis of Demand-Control-Support model in relation to activity satisfaction and psychological well-being. The subjects were 300 elderly women participating in productive activity for example paid work, voluntary activity, and grancdhildren care. This research tested four hypotheses concerning the DCS model. Is there support for the isolation hypothesis, such that the lowest level of activity satisfaction is experienced by the elderly women working in an isolation situation(high demand-low control-low support)? Is there support for the isolation hypothesis, such that the lowest level of psychological well-being is experienced by the elderly women working in an isolation situation(high demand-low control-low support)? Is there support for the buffer hypothesis, i. e. interaction between demand, control, and support, indicating a buffering effect of support on the negative impact of high strain on activity satisfaction? Is there support for the buffer hypothesis, i. e. interaction between demand, control, and support, indicating a buffering effect of support on the negative impact of high strain on psychological well-being? Major results of this study were as follows. and were supported. Activity satisfaction and psychological well-being of the elderly women in isolation situation was the lowest among the sample. was supported that family support level buffered the negative impact of high strain on activity satisfaction. But was not supported. Only main effect of demand level was showed on psychological well-being.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.374-385
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• 2022

In order to investigate the application of 3D base-seismic isolation system in nuclear power plants (NPPs), comprehensive analysis of constitution and design theory for 3-dimensional combined isolation bearing (3D-CIB) was presented and derived. Four different vertical stiffness of 3D-CIB was designed to isolate the nuclear island (NI) building. This paper aimed at investigating the isolation effectiveness of 3D-CIB through modal analysis and dynamic time-history analysis. Numerical results in terms of dynamic response of 3D-CIB, relative displacement response, acceleration and floor response spectra (FRS) of the superstructure were compared to validate the reliability of 3D-CIB in mitigating seismic response. The results showed that 3D-CIB can significantly attenuate the horizontal acceleration response, and a fair amount of the vertical acceleration response reduction of the upper structure was still observed. 3D-CIB plays a significant role in reducing the horizontal and vertical FRS, the vertical FRS basically do not vary with the floor height. The smaller the vertical stiffness of 3D-CIB is, the better the vertical isolation effectiveness is, whereas, it will increase the displacement and the rocking effect of superstructure. Although the advantage of 3D-CIB is that the vertical stiffness can be flexibly adjusted, it should be designed by properly accounting for the balance between the isolation effectiveness and displacement control including rocking effect. The results of this study can provide the technical basis and guidance for the application of 3D-CIB to engineering structure.

• 대한미생물학회지
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• 제9권1호
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• pp.13-18
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• 1974

Blood is one of the most important clinical specimens for the isolation of bacteria. A rapid isolation and a high isolation rate of bacteria are very important in blood culture because bacteremic patients are mostly in grave condition. Various blood culture media which support growth of most fastidious bacteria are available commercially. However, growth of bacteria are frequently delayed because of antibacterial activity of blood. Sodium polyanethol sulfonate(Liquoid) has been reported to inactivate the antibacterial substance and disrupt phagocytic cells. The beneficial effect of SPS is well recognized in the isolation of gram-positive bacteria. However, the effect does not seem to be prominent for gram-negative bacilli isolation mainly due to the rapidity of their growth. It has been experienced with Sal. typhi that the growth is much slower than that of other gram-negative bacilli. For the rapid growth of the organism, use of bile broth has been recommended. Although Sal. typhi is the most frequently isolated organism at present, about one half of total isolates are other organisms and, in case bile broth is used, other media which support growth of these organisms should be used together. Fluid thioglycollate medium(FTM) which is always used in blood culture to isolate anaerobes is inferior to brain heart infusion(BHI) for the isolation of aerobes. This study was done to determine the effect of SPS on the isolation of Sal. typhi from blood. During the Sep. 1973 to Sep. 1974 study period, 2460 blood cultures were made from the Severance hospital patients: BHI and FTM sets 1431 specimens, BHI with SPS(0.05%) and FTM sets 396 specimens, BHI and FTM with SPS sets 359 specimens, BHI and BHI with SPS sets 274 specimens. Mean incubation time required for the macroscopic detection of growth of Sal. typhi were 3.5 days on BHI and 2.7 days on BHI with SPS. The 0.8 day difference was statistically significant. On FTM the mean incubation time was 3.8 days while it was 2.9 days on FTM with SPS. The 0.9 day difference was statistically significant. The result on BHI with and without SPS sets showed faster growth on BRI with SPS in 7 specimens and slower growth in one specimen and the remaining 12 showed growth at the same time. These specimens had mean incubation time of 3.2 days on BHI and 2.3 days on BHI with SPS. The 0.9 day difference was statistically significant. This study indicates beneficial effect of SPS for the rapid isolation of Sal. typhi from clinical blood specimens.

• 한국구조물진단유지관리공학회 논문집
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• 제14권6호
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• pp.93-99
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• 2010

본 논문에서는 상부구조에 있어서 보-기둥 강성비 변화에 따른 골조의 특성과 상부구조와 면진층 간의 진동주기비에 따른 면진효과를 분석해 보고, 상부골조의 주기와 목표 면진주기의 설정에 따라 면진효과가 어떻게 달라지는가에 대한 정보를 제공하여 향후 면진건물을 설계하기 위한 기본계획을 세우는데 있어서 필요한 기초 자료를 제공하고자 한다. 그 결과 건물골조의 경우 유효한 면진효과를 얻기 위해서는 최소한 상부구조의 고유진동주기 대비 2.5배 이상의 면진주기를 확보하고, 목표 면진주기를 2.0초 이상으로 설정하여 설계할 것을 추천한다.

• 한국공간구조학회논문집
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• 제9권4호
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• pp.97-103
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• 2009

면진장치는 기초와 구조물 사이 에 면진장치를 설치하여 상부로 전달되는 지진에너지를 감소시키는 장치로 면진장치의 설치위치에 따라서 기초면진과 중간(지붕)면진으로 구분할 수 있다. 본 연구에서는 면진장치 설치 위치에 따른 아치구조물의 지진응답을 비교 분석하여 면진장치의 효용성을 검증하였다. 지붕면진 시스템은 기초면진 시스템과 비교하여 상부 지붕구조의 지진응답 저감에 있어서 보다 효과적이다. 또한 하부구조와 상부구조의 강성 및 질량변화 그리고 시공성에 있어서 지붕면진이 기초면진 시스템 보다 우수한 것으로 사료된다.

• Smart Structures and Systems
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• 제31권3호
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• pp.213-227
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• 2023

A passive prismatic-shaped isolation platform (PIP) is proposed to realize enhanced quasi-zero stiffness (QZS) effect. The design concept uses a horizontal spring to produce a tunable negative stiffness and installs oblique springs inside the cells of the prismatic structure to provide a tunable positive stiffness. Therefore, the QZS effect can be achieved by combining the negative stiffness and the positive stiffness. To this aim, firstly, the mathematical modeling and the static analysis are conducted to demonstrate this idea and provide the design basis. Further, with the parametric study and the optimal design of the PIP, the enhanced QZS effect is achieved with widened QZS range and stable property. Moreover, the dynamic analysis is conducted to investigate the vibration isolation performance of the proposed PIP. The analysis results show that the widened QZS property can be achieved with the optimal designed structural parameters, and the proposed PIP has an excellent vibration isolation performance in the ultra-low frequency due to the enlarged QZS range. Compared with the traditional QZS isolator, the PIP shows better performance with a broader isolation frequency range and stable property under the large excitation amplitude.