• Title/Summary/Keyword: 구조적 안정도

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Mechanical Effects of Back Supporting Beam of Assembled Earth Retaining Wall on Field Model Tests Results (현장모형실험을 통한 AER옹벽의 지주보의 역학적 효과)

  • Kim, Hongsun;Im, Jong-Chul;Choi, Junghyun;Seo, Minsu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.2
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    • pp.343-355
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    • 2017
  • In this study, an Assembled Earth Retaining Wall (AER wall) is newly proposed. The AER wall combined stabilizing piles names as Back Supporting Beam is developed to improve stability and economics of existing retaining walls. For the verification of the AER wall, the field model tests and 3D numerical analyses were performed. As a result of the field tests, it can be confirmed that the earth pressure is considerably reduced compared with the L-shaped retaining wall. Also, the 3D numerical analyses show that AER wall is at least 29.85% more effective at lateral displacement than general L-shaped retaining wall. In other words, AER wall is expected to raise economical efficiency because of excellent mechanical stability of Back Supporting Beam.

Fabrication Method and Performance Evaluation of Micro Igniter for MEMS Thruster (MEMS 추력기를 위한 마이크로 점화기의 제작 방법 및 성능 평가)

  • Lee, Jongkwang
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.1
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    • pp.1-8
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    • 2015
  • Micro igniter on the glass membrane for MEMS thruster was developed. The stability of the micro igniter by using a glass membrane with a thickness of tens of microns was improved. The micro igniter was fabricated by anisotropic wet etching of photosensitive glass and deposition of Pt/Ti for electric heat coil. The solid propellant was loaded into the propellant chamber without an especial technique due to the high structural stability of the glass membrane. Ignition tests were performed successfully. The minimum ignition delay was 27.5 ms with an ignition energy of 19.3 mJ.

Stabilization Inverse Optimal Control of Nonlinear Systems with Structural Uncertainty (구조적 불확실성을 갖는 비선형 시스템의 안정화 역최적제어)

  • Cho, Do-Hyeoun;Lee, Chul;Lee, Jong-Yong
    • 전자공학회논문지 IE
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    • v.46 no.4
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    • pp.49-56
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    • 2009
  • In this paper, stabilization inverse optimal control for nonlinear systems with structural uncertainty is considered. Based on the control Lyapunov function, a theorem for the globally asymptotic stability is presented. From this a less conservative condition for the inverse optimal control is derived. The result is used to design an inverse optimal controller for a class of nonlinear systems, that improves and extends the existing results. The class of nonlinear system considered is also enlarger. The simulation results show the effectiveness of the method.

Provable Security for the Skipjack-like Structure (Skipjack 구조에 대한 DC 및 LC의 안정성 증명)

  • 성재철
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.10 no.1
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    • pp.13-22
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    • 2000
  • 본 논문에서는 Skipjack의 변환규칙 A와 같은 반복적인 구조에 대한 차분 특성 및 선형 근사식의 확률의 상한 값을 제시하고 이를 증명한다. 즉 라운드 함수에 대한 확률의 최대 값이 p이면 15라운드 후에 p4이 됨을 보인다. 따라서 본 논문에서 고려한 구조는 현재까지 DC 및 LC에 대한 안전성을 증명할 수 있는 구조인 Feistel 구조 및 MISTY 구조와 더불어 블록 암호의 설계 방법에 대한 다양성을 제공한다.

Effects of Nitrogen Addition on Thermal Stability of Ta-Al Alloy Films (Ta-Al 합금박막의 열적안정성에 미치는 질소첨가 효과)

  • Jo, Won-Gi;Kim, Tae-Yeong;Gang, Nam-Seok;Kim, Ju-Han;An, Dong-Hun
    • Korean Journal of Materials Research
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    • v.7 no.10
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    • pp.877-883
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    • 1997
  • Ar 및 Ar과 $N_{2}$ 분위기하에서 rf 마그네트론 스퍼터링방법으로 Ta-AI과 Ta-AI-N합금막을 제조하였다. Ta-7.9at.% AI계열, Ta-26.7 at% AI게열과 Ta-45.4at.%AI계열에 Ar에 대한 질서유량비로 26%까지 질소를 첨가하여 Ta-AI-N박막을 증착한후, 300-$600^{\circ}C$온도 구산에서 열처리 전후의 구조 및 전기적 특성과 열적안정성을 통하여 레지스터의 적용가능성을 조사하였다. 구조 및 조성 분석은 X-선 회절과 Rutherford Backscattering Spectrometry(RBS)로 관찰하였고 열적안정성은 4단자법(four point probe method)을 이용한 저항변화를 통하여 측정하였다. 순수 Ta에 AI을 첨가하면 확장된 $\beta$($\beta$-Ta)N 합금박막에서 가장 열적안정성이 우수하게 나타났던 질소첨가 범위는 Ta $N_{hcp}$또는 TaN/ sub fcc/또는 Ta $N_{fcc}$와 비정질과의 혼합상순으로 상천이를 나타내었다. Ta-AI-N 합금박막에서 가장 열적안정성이 우수하게 나타났던 질서첨가 범위는 Ta-26.7at. % AI계열의 경우 19-36at.% $N_{2}$구간이었고, Ta-45.5at.% AI계열의 경우는 30-45at.%구간이었다. Ta-AI합금박막은 질소가 첨가되지 않아도 열처리 온도 및 시간에 따라 약 10% 이내의 비교적 작은 저항변화를 보여 열적안정성이 우수하지만 질소를 첨가하여 Ta-AI-N합금박막을 형성시킬경우, 증착된 상태에서 이미 큰 비저항을 나타내었고 열처리 동안 3%이내의 매우 작은 저항변화를 나타내었기 때문에 레지스터용 재료로써 열적안정성에 대한 잠재력이 크다.

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Study on the structure of cAMP receptor protein(CRP) by temperature change (온도변화에 의한 cAMP 수용성 단백질(CRP)의 구조)

  • 주종호;구미자;강종백
    • Journal of Life Science
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    • v.10 no.3
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    • pp.279-285
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    • 2000
  • CRP (cyclic AMP receptor protein) regulate transcription of catabolite-sensitive genes in Escherichia coli. Wild-type and mutant CRP (S83G and S128A) proteins were used to measure the thermal stability and the temperature-dependent structural change by proteolytic digestion, UV spectrophotometer and CD spectrapolarimeter. The result indicated that wild-type CRP was more thermally stable than the mutant CRPs in the presence of cAMP. At a low temperature, wild-type CRP with cAMP was more sensitive to subtilisin than the mutant CRPs. At a high temperature, there was no difference of sensitivity to subtilisin among wild-type, S83G and S128A CRPs. CD spectra suggested that the secondary structure of CRP was destroyed partially at a high temperature.

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Derivation of Important Factors the Resilience of Purchased Land in the Riparian Zone Using AHP Analysis (AHP분석을 활용한 수변구역 매수토지의 회복탄력성 중요인자 도출)

  • Back, Seung-Jun;Lee, Chan;Jang, Jae-Hoon;Kang, Hyun-Kyung;Lee, Soo-Dong
    • Korean Journal of Environment and Ecology
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    • v.35 no.4
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    • pp.387-397
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    • 2021
  • This study aims to present reference data necessary for developing evaluation indicators to analyze the actual resilience of purchased land by investigating the factors that affect the restoration of the purchased land in the riparian zone and quantitatively calculating its importance. The main results are as follows. Firstly, this study identified 34 potential resilience factors through a literature review encompassing domestic and overseas studies and derived seven ecological responsiveness factors, six physical responsiveness factors, and four managerial responsiveness factors through the Delphi survey. Secondly, reliability analysis and Analytic Hierarchy Process (AHP) analysis derived the following important factors: structural stability of the vegetation restored in the purchased land, species diversity of wildlife, structural stability of wildlife, the size of restored wetland after purchase, number of plant species, and the land cover status adjacent to the purchased land. The study results are expected to be helpful information for ecological restoration and management plans reflecting reinforcing factors for resilience at each stage of land purchase, restoration, and management.

Reliable and Effective Overlay Network based Dissemination System for Flash Dissemination (플래쉬 디세미네이션을 위한 안정적이고 효과적인 오버레이 네트워크 기반 전송 시스템)

  • Kim, Kyung Baek
    • Smart Media Journal
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    • v.2 no.1
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    • pp.8-16
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    • 2013
  • The significant enhancement of the edge portion of computer networks including user-side machines and last mile network links encourages the research of the overlay network based data dissemination systems. Varieties of overlay network based data dissemination systems has distinct purposes, and each of them has a proper structure of an overlay network and a efficient communication protocol. In this paper, overlay network based data dissemination systems for Flash Dissemination, whose target is the distribution of relatively small size data to very large number of recipients within very short time, are explored. Mainly two systems, RECREW and FaReCAST, are introduced and analyzed in the aspects of design considerations for overlay networks and communication protocols. According to evaluations for flash dissemination scenarios, it is observed that the proposed overlay network based flash dissemination systems outperforms the previous overlay network based multicasting systems, in terms of the reliability and the dissemination delay. Moreover, the theoretical analysis of the reliability of data dissemination is provided by analysing FaReCAST.

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