• Smart Structures and Systems
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• 제17권5호
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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.

• 대한토목학회논문집
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• 제12권2호
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• pp.35-42
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• 1992

본 논문에서는 주 구조물 내에 설치된 기기의 지지점에 감진계통을 도입함으로써 지진하중에 대한 기기의 응답감소효과를 연구하였으며, 효율적인 해석을 수행하기 위해 구조물-기기 상호작용 고려 및 축소 행렬방법을 이용한 전산프로그램(KBISAP)을 개발하였다. 지지점에 감전장치가 설치된 기기의 지진하중에 대한 응답감소 효율성을 평가하기 위해 세가지 해석모델, 즉 고정기초구조물 상의 지지점이 고정된 기기, 감진기초구조물 상의 지지점이 고정된 기기 및 고정기초구조물 상의 지지점에 감진계통이 설치된 기기를 채택한 예제해석 결과, 본 논문에서 채택한 방법이 일반적인 고정기초구조물은 물론 감진기초구조물 상에 설치된 기기의 지진하중에 대한 응답감소 보다 더 효율적임을 알 수 있었다. 따라서 본 방법은 기기의 응답감소는 물론 중요한 기기의 안전성 향상에 효과적이다.

• Structural Engineering and Mechanics
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• 제23권6호
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• pp.615-634
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• 2006

Seismic response of the liquid storage tanks isolated by the elastomeric bearings and sliding systems is investigated under near-fault earthquake motions. The fault normal and parallel components of near-fault motion are applied in two horizontal directions of the tank. The continuous liquid mass of the tank is modeled as lumped masses known as sloshing mass, impulsive mass and rigid mass. The corresponding stiffness associated with these lumped masses has been worked out depending upon the properties of the tank wall and liquid mass. It is observed that the resultant response of the isolated tank is mainly governed by fault normal component with minor contribution from the fault parallel component. Further, a parametric study is also carried out to study the effects of important system parameters on the effectiveness of seismic isolation for liquid storage tanks. The various important parameters considered are: aspect ratio of tank, the period of isolation and the damping of isolation bearings. There exists an optimum value of isolation damping for which the base shear in the tank attains the minimum value under near-fault motion. The increase of damping beyond the optimum value will reduce the bearing and sloshing displacements but increases the base shear. A comparative performance of five isolation systems for liquid storage tanks is also studied under normal component of near-fault motion and found that the EDF type isolation system may be a better choice for design of isolated tank in near-fault locations. Finally, it is also observed that the satisfactory response can be obtained by analysing the base-isolated tanks under simple cycloidal pulse instead of complete acceleration history.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1993년도 학술논문발표회 논문집 제12권 1호
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• pp.121-124
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• 1993

This paper is a study on the word recognition using neural network. A limited vocabulary, speaker independent, isolated word recognition system has been built. This system recognizes isolated word without performing segmentation, phoneme identification, or dynamic time wrapping. It needs a static pattern approach to recognize a spatio-temporal pattern. The preprocessing only includes preceding and tailing silence removal, and word length determination. A LPC analysis is performed on each of 24 equally spaced frames. The PARCOR coefficients plus 3 other features from each frame is extracted. In order to simplify a structure of neural network, we composed binary code form to decrease output nodes.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.700-703
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• 2004

The purpose of this study is to present the design methodology of base isolated buildings. To achieve the goal of this study, time-history analysis was performed with seismic performance level and recorded seismic data. From the analysis results of MDOF system, the maximum. displacement and base shear were evaluated as 25 cm and $4\%$ by the input level which is maximum velocity of 50 kine. By introducing hybrid isolation system, seismic energy can be concentrated consequently high seismic capacity of the total building is secured.

• Bulletin of the Korean Chemical Society
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• 제23권5호
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• pp.727-735
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• 2002

Proton coupled carbon-13 relaxation experiment was performed to investigate the effect of vicinal protons on spin-lattice relaxation of methylene carbon-13 in n-undecane. A BIRD type pulse sequence was employed as a way to check the validity of describing the 13CH2 moiety as an isolated AX2 spin system. The results show that the presence of vicinal protons exerts substantial influence on the relaxation of methylene carbon-13, indicating that it is not a very good approximation to treat a methylene moiety as an isolated AX2 spin system.

• 한국안전학회지
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• 제16권4호
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• pp.96-102
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• 2001

In construction sites, portable generators and electrical equipments cause frequently electrical accidents due to the poor condition of their usage. However, there are very few technical guidelines on these equipments even though they have serious accident causing potentiality. In order to reduce such accidents in practical and economical, grounding methods are studied in this paper as the countermeasure of electrical accidents. Several Korean national standards and international standards regarding three grounding types are compared each other, and some prevention means of electrical accidents are reviewed in this study. This paper presents the most effective grounding methods by assuming the WCS with the isolated power systems.

• 대한임상검사과학회지
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• 제45권4호
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• pp.144-148
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• 2013

Candida spp. are yeast form fungi, which cause an opportunistic infections in a immune suppressed patients however it is a normal flora of the respiratory system, the gastrointestinal system, and the urogenital system of healthy person. It is investigated that the distribution of Candida spp. cause an oral disease from oral cavity of healthy people and also identified Candia dubliniensis. Distribution and identification of the yeast form fungi in oral cavities of healthy people was investigated by an automatic identifier, VITEK2 system. We found 21 strains of Candida albicans, 3 strains of Candida famata, one strain of Candida tropicalis, Candida haemulonii, Candida krusei, and Candida dubliniensis. In addition, one strain of Cryptococcus spp., Saccharomyces spp., and two unknown strains were isolated. Candida dubliniensis which forms a mass by more than 2 chlamydospores was isolated from a healthy person for the first time. Candida dubliniensis was not grown at $42^{\circ}C$ whereas Candida albicans was grown well. It is known that Candida dubliniencis was isolated in AIDS while it is found in healthy people from this study, which will be helpful to investigate the distribution of Candida spp.

• Smart Structures and Systems
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• 제22권4호
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• pp.383-397
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• 2018

Traditional base isolation systems focus on isolating the seismic response of a structure in the horizontal direction. However, in regions where the vertical earthquake excitation is significant (such as near-fault region), a traditional base-isolated building exhibits a significant vertical vibration. To eliminate this shortcoming, a rocking-isolated system named Telescopic Column (TC) is proposed in this paper. Detailed rocking and isolation mechanism of the TC system is presented. The seismic performance of the TC is compared with the traditional elastomeric bearing (EB) and friction pendulum (FP) base-isolated systems. A 4-storey reinforced concrete moment-resisting frame (RC-MRF) is selected as the reference superstructure. The seismic response of the reference superstructure in terms of column axial forces, base shears, floor accelerations, inter-storey drift ratios (IDR) and collapse margin ratios (CMRs) are evaluated using OpenSees. The results of the nonlinear dynamic analysis subjected to multi-directional earthquake excitations show that the superstructure equipped with the newly proposed TC is more resilient and exhibits a superior response with higher margin of safety against collapse when compared with the same superstructure with the traditional base-isolation (BI) system.

• 한국컴퓨터정보학회논문지
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• 제23권10호
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• pp.57-63
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• 2018

The operating system for an isolated microgrid, which is completely disconnected from the central power system, aims at preventing blackouts and minimizing power generation costs of diesel generators through efficient operation of the energy storage system (ESS) that stores energy produced by renewable energy generators and diesel generators. In this paper, we predict the amount of renewable energy generation using the weather forecast and build an optimal diesel power generation plan using a genetic algorithm. In order to avoid inefficiency due to inaccurate prediction of renewable energy generation, our search algorithm imposes penalty on candidate diesel power generation plans that fail to maintain the SOC (state of charge) of ESS at an appropriate level. Simulation experiments show that our optimization method for maintaining an appropriate SOC balance can prevent the blackout better when compared with the previous method.