• Title/Summary/Keyword: 성능 격리

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A Study on Base Isolation Performance and Phenomenological Model of E-Shape Steel Hysteretic Damper (E-Shape 강재이력댐퍼의 수치모델과 기초격리구조물의 지진응답)

  • Hwang, Inho;Ju, Minkwan;Sim, Jongsung;Lee, Jong Seh
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5A
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    • pp.685-690
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    • 2008
  • Recently, as large structures become lighter and more flexible, the necessity of structural control for reducing excessive displacement and acceleration due to seismic excitation is increased. As a means to minimize seismic damages, various base isolation systems are adopted or considered for adoption. In this study, a base isolation system using hysteretic damper is shown to effectively protect structures against earthquakes. A mechanical model is determined that can effectively portray the behavior of a typical E-shape device. Comparison with experimental results for a hysteretic damper indicates that the model is accurate over a wide range of operating conditions and adequate for analysis. The seismic performance of hysteretic dampers are studied and compared with the conventional systems as a base isolation system. A five-story building is modeled and the seismic performance of the systems subjected to three different earthquake is compared. The results show that the hysteretic damper system can provide superior protection than the other systems for a wide range of ground motions.

Optimal Design of a One-chip-type SAW Duplexer Filter Using Micro-strip Line Lumped Elements (마이크로 스트립라인 집중소자를 이용한 일체형 탄성표면파 듀플렉서 필터의 최적설계)

  • 이승희;이영진;노용래
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.3
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    • pp.83-90
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    • 2001
  • Conventional SAW duplexer filters employ a 1/4 wavelength transmission line, which causes difficulty in fabrication of the strip line on the package. Its manufacturing process is also complicated, because it needs integrating process of the separate transmitting filter, receiving filter and isolation circuits. This paper concerns development of a new structure of the duplexer filter that has all the transmitting filter, the receiving filter and the isolation circuit as a one chip device. For composition of the duplexer, we design the component SAW ladder filters and the isolation network consisting of lumped inductor and capacitor elements. Performance of the whole duplexer is optimized by the nonlinear multivariable minimization of a proper target function, and the result is compared with that of commercial filters.

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Study on Improvement of the Array Antenna Performance by Isolation Enhancement (격리도 향상을 통한 배열안테나의 성능개선 연구)

  • Park, Minseo;Lee, Jae-Gon;Lee, Jeong-Hae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.3
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    • pp.229-238
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    • 2016
  • In this paper, we have studied isolation enhancement using a suppression of surface wave to improve performance of array antenna. To reduce isolation between elements of array antenna, perfect magnetic conductor(PMC) and SOFT-surface is designed and located at center of ground plane, isolation and gain is simulated by commercial full wave simulator(HFSS). As a result, isolation of more than 40 dB and gain improvement of 2.2 dBi are obtained at E-plane array in case of both PMC and SOFT-surface. At H-plane array, air coupling is dominant compared to coupling by surface wave. It is conclude that this study is useful for design of compact array antenna and performance improvement of array antenna.

Comparative Seismic Design of Bridges with Lead Rubber and Steel Bearings for the Ductile Failure Mechanism (지진격리교량과 강재받침교량의 연성파괴메커니즘에 의한 비교내진설계)

  • Kook, Seung Kyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1A
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    • pp.173-181
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    • 2006
  • Many isolated bridges are designed and constructed after the introduction of the seismic design. However those bridges designed in engineering fields have unnecessarily high serviceability limit and brittle failure mechanism, which do not satisfy the seismic design concept. Such design results are due to the excessive substructure stiffness of the conventional design method as well as the misunderstanding of the seismic design method. In this study an isolated bridge designed with the conventional design method is selected and the same bridge with steel bearings is modelled for the comparative seismic design. From the comparison, the seismic design procedures satisfying the required performance levels are provided for the two bridges. It is confirmed that the isolated bridge requires more complicated design procedure with trial and error methods and reanalyses but provides higher serviceability limit compared to the bridge with steel bearings. However, because the required serviceability limit can also be obtained by adjusting substructure stiffness, it is a resonable seismic design process that an isolated bridge is to be considered as an alternative design when the ductile failure mechanism is not obtained with a bridge with steel bearings.

The Role of Microporous Separator in Lithium Ion Secondary Battery (리튬이온 이차전지에서의 미세다공성 격리막의 역할)

  • 이영무;오부근
    • Membrane Journal
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    • v.7 no.3
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    • pp.123-130
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    • 1997
  • The characteristics of microporous separator for lithium ion secondary battery was introduced. Microporous separator is a key component of a lithium ion secondary battery because its basic properties were related with the performance and safety of the battery. Up to now, stretched microporous polyolefins such as polyethylene(PE) separator were mainly applied. It is still required to enhance wettability and shut-down property. For this purpose, the application of fluorovinylic polymers and surface modification of conventional polyolefinic microporous membrans we being continuously tried.

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Isolated Word Recognition Based on Finite-State Vector Quantization (유한상태 벡터양자화를 이용한 격리단어인식)

  • 윤원식;은종관
    • The Journal of the Acoustical Society of Korea
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    • v.5 no.3
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    • pp.50-57
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    • 1986
  • 유한상태 벡터양자화 방법을 이용한 격리단어인식에 관하여 기술하고 있다. 이 인식시스템은 codebook과 next-state function 으로 구성된 일종의 finite-state machine으로 볼 수 있다. 유한상태 벡 터양자화방법을 이용한 격리단어 인식시스템은 일반적인 벡터양자화방법을 이용한 인식시스템에 비하여 소요시간이 감소하며 입력음성을 분할할 필요도 없는 한편 두 시스템의 인식율은 비슷한 것으로 나타났 다. Next-state function을 구하는 방법에는 conditional histogram 방법과 omniscient design 방법이 있 으며, 이 방법들의 성능비교를 위해 영부터 구까지의 한국어 숫자음성에 대한 인식실험을 수행하였다.

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Analysis of Data Isolation Methods for Secure Web Site Development in a Multi-Tenancy Environment (멀티테넌시 환경에서 안전한 웹 사이트 개발을 위한 데이터격리 방법 분석)

  • Jeom Goo Kim
    • Convergence Security Journal
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    • v.24 no.1
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    • pp.35-42
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    • 2024
  • Multi-tenancy architecture plays a crucial role in cloud-based services and applications, and data isolation within such environments has emerged as a significant security challenge. This paper investigates various data isolation methods including schema-based isolation, logical isolation, and physical isolation, and compares their respective advantages and disadvantages. It evaluates the practical application and effectiveness of these data isolation methods, proposing security considerations and selection criteria for data isolation in the development of multi-tenant websites. This paper offers important guidance for developers, architects, and system administrators aiming to enhance data security in multi-tenancy environments. It suggests a foundational framework for the design and implementation of efficient and secure multi-tenant websites. Additionally, it provides insights into how the choice of data isolation methods impacts system performance, scalability, maintenance ease, and overall security, exploring ways to improve the security and stability of multi-tenant systems.

Performance Test of C-shape Steel Base Isolation System (C형 강재 지진격리장치의 성능시험)

  • Jung, Dae-Yu;Shim, Chul-Hwan;Park, Hyung-Ghee
    • Journal of the Earthquake Engineering Society of Korea
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    • v.13 no.4
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    • pp.25-35
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    • 2009
  • This paper introduces the performance of a newly developed base isolation system made from the combination of a polyurethane disk - attached pot bearing and C-shape steel dampers. Ultimate compressive load tests, ultimate rotation tests, dynamic tests, and dynamic load repeat tests have been completed to determine dynamic characteristics and to verify performance characteristics. The experimental results are compared with the analytic results. It is determined that all requirements for bridge bearing in the specifications are satisfied, and that adequate energy dissipation has occurred. The EDC and effective stiffness estimated by tests are similar to the theoretical values.

Experimental Study on the Characteristics of Steel Hysteretic Dampers with E-Shape Elements (E-Shape 강재이력댐퍼의 거동 분석)

  • 김인배;강형택;이민구;서주원
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.03a
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    • pp.457-464
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    • 2003
  • 최근 교량의 건설에 있어서 내진설계가 주요문제로 부각되면서, 구조물의 진동응답을 제어 하는 갖가지 형태의 진동제어 기법이 적용되고 있다. LRB(Lead Rebbe. Bearing), LUD(Lock Up Device)등 다양한 지진격리장치가 설계에 적용되고 있으며 특히, 설계변경 .내진보수보강과 같이 제약 조건이 있는 상황에서 유용한 면진방법으로 사용되고 있다. 이러한 지진격리장치는 기본적인 설계특성인 수평강성, 감쇠성능에 대한 검증을 필요로 한다. 특히, 지진과 같은 동적하중에 대하여 하중속도, 수직력, 변형률 등에 대한 의존성과 내구성의 검토가 필요하며 유사장치에 대하여 검증실험기준의 정립이 진행 중에 있다. 강재이력댐퍼인 E-Shape 댐퍼는 지진격리장치로서 교각의 고정단에 교좌장치로 설치되어 상시에는 탄성영역 내에서 거동하는 고정단의 역할을 하다가, 지진발생시에는 E-Shape형태의 강재댐퍼가 소성변형을 통한 이력거동으로 에너지 소산기능을 가진 교좌장치이다. 최근 LRB에 대하여는 다양한 특성실험이 수행되고 있으나 상대적으로 강재이력댐퍼에 대하여는 이러한 검증실험이 수반되지 않고 사용되고 있다. 본 실험연구에서는 E-Shape 강재이력댐퍼에 대하여 연직하중, 수평변형률, 수평속도에 패한 동적특성을 평가함으로서 강재이력댐퍼를 이용한 지진격리설계의 타당성과 면진성능을 평가해 보았다.

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Optimal design of nonlinear seismic isolation system by a multi-objective optimization technique integrated with a stochastic linearization method (추계학적 선형화 기법을 접목한 다목적 최적화기법에 의한 비선형 지진격리시스템의 최적설계)

  • Kwag, Shin-Young;Ok, Seung-Yong;Koh, Hyun-Moo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.2
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    • pp.1-13
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    • 2010
  • This paper proposes an optimal design method for the nonlinear seismic isolated bridge. The probabilities of failure at the pier and the seismic isolator are considered as objective functions for optimal design, and a multi-objective optimization technique is employed to efficiently explore a set of multiple solutions optimizing mutually-conflicting objective functions at the same time. In addition, a stochastic linearization method is incorporated into the multi-objective optimization framework in order to effectively estimate the stochastic responses of the bridge without performing numerous nonlinear time history analyses during the optimization process. As a numerical example to demonstrate the efficiency of the proposed method, the Nam-Han river bridge is taken into account, and the proposed method and the existing life-cycle-cost based design method are both applied for the purpose of comparing their seismic performances. The comparative results demonstrate that the proposed method not only shows better seismic performance but also is more economical than the existing cost-based design method. The proposed method is also proven to guarantee improved performance under variations in seismic intensity, in bandwidth and in the predominant frequency of the seismic event.