• 제목/요약/키워드: weak layers

검색결과 169건 처리시간 0.02초

스마트융합시대 취약계층에 대한 정보격차 해소 방안 (A Study on Efficient Policies of solving the Digital Divide for Weak Layers in the Smart Phone Convergence Era)

  • 강월석;양해술
    • 디지털융복합연구
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    • 제10권1호
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    • pp.29-38
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    • 2012
  • 새롭게 다가오고 급변하는 스마트 융합환경속에서 정보격차 해소 이슈가 새롭게 조명되고 있다. 전통적인 정보격차의 개념과 범주에 대해 정의하고 그동안 정부가 정보격차 해소를 위해 펼쳐온 노력 사항에 대해 알아보고 해외주요 국가들의 스마트 융합환경속에서의 정보격차 현황에 대해 살펴보았다. 해외 주요국과 한국과의 스마트폰 환경 하에서의 장노년층, 장애인, 저소득층등 취약 계층별 정보 격차 현상에 대해 살펴보고 특별한 차별점을 인식하려 노력하였다. 이에 따른 시사점 분석을 통해 필요한 정책방안을 제시하고 그 달성을 위해 우리 정부나 산업계, 학계, 사회단체 등에서 어떠한 노력을 기울여야 할 것인가를 제시하였다. 정보통신 일등국가로서의 위치를 계속 유지해나가는 것은 전 국민이 평등하게 정보를 공유하여 모두가 삶이 행복한 사회를 구현할 때 비로소 가능해 지는 것이라고 믿는다. 본 연구에서 제시하는 전략안이나 제언이 정부의 정보통신정책 마련에 도움이 되었으면 한다.

지구통계학적 기법을 이용한 연약 지반 분포 추정 (Estimation of Distribution of the Weak Soil Layer for Using Geostatistics)

  • 정진;장원일
    • Journal of Advanced Marine Engineering and Technology
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    • 제35권8호
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    • pp.1132-1140
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    • 2011
  • 해상풍력발전단지 건설 시 기초지반이 해상 점성토층의 지반일 경우 플랜트 자체 하중의 영향과 풍력과 같은 외부 모멘트 영향으로 인해 침하 발생을 야기할 수 있기 때문에 연약지반 분포를 파악하는 것은 풍력플랜트 입지를 위해 매우 중요한 사항이다. 이러한 연약지반 분포를 파악하는 방법은 시추조사 방법이 가장 최적의 방법이지만, 현장의 여건이나 경제적 제약이 큰 단점을 가지고 있다. 따라서 이러한 문제점을 보완하기 위해 현재 지구통계학적 방법을 이용한 연구가 활발하게 진행되고 있다. 본 연구에서는 풍력 플랜트 설치를 가정한 해상 영역을 설정하여 지구통계학적 기법을 통하여 연약 지반층 두께 분포의 추정을 연구 수행하였다. 연약 지반층은 표준 관입시험치의 결과를 이용하여 구분하였으며, 지구통계학적 기법은 정규크리깅과 순차가우시안 시뮬레이션을 이용하여 결과를 비교하였다. 그 결과 비슷한 영역에서 최대 점성토의 두께를 가지는 영역이 나타남을 파악할 수 있었으며, 그 결과의 불확실성을 정량적으로 평가할 수 있었다.

미고결 퇴적암층에서의 현장타설말뚝 지지력 특성 연구 (Bearing Capacity of In-situ Cast Piles in Weak Sedimentary Rocks)

  • 심동현;김기섭;유석준
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2004년도 춘계학술발표회
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    • pp.100-109
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    • 2004
  • Is this study, results of static pile load tests of in-situ cast piles in weak or uncemented sedimentary rock layers have been analyzed and presented. Consdierations on the characteristics of soils sedimentary rocks have been made. From the measurements of strain gauges and extensometers the relationship of unit skim friction versus displacement and that of unit end bearing versus displacement have been obatined to verity the characteristics of bearing capacity of this uncemented sedimentary rock layers. Also, a comparison has been made between ultimate skin friction in compression and tension.

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A UNIFORMLY CONVERGENT NUMERICAL METHOD FOR A WEAKLY COUPLED SYSTEM OF SINGULARLY PERTURBED CONVECTION-DIFFUSION PROBLEMS WITH BOUNDARY AND WEAK INTERIOR LAYERS

  • CHAWLA, SHEETAL;RAO, S. CHANDRA SEKHARA
    • Journal of applied mathematics & informatics
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    • 제33권5_6호
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    • pp.635-648
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    • 2015
  • We consider a weakly coupled system of singularly perturbed convection-diffusion equations with discontinuous source term. The diffusion term of each equation is associated with a small positive parameter of different magnitude. Presence of discontinuity and different parameters creates boundary and weak interior layers that overlap and interact. A numerical method is constructed for this problem which involves an appropriate piecewise uniform Shishkin mesh. The numerical approximations are proved to converge to the continuous solutions uniformly with respect to the singular perturbation parameters. Numerical results are presented which illustrates the theoretical results.

A STRESS ANALYSIS FOR A COATED FUEL PARTICLE OF A HTGR USING A FINITE ELEMENT METHOD

  • Kim, Young-Min;Cho, Moon-Sung
    • Nuclear Engineering and Technology
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    • 제41권8호
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    • pp.1087-1100
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    • 2009
  • A finite element method utilizing the Galerkin form of the weighted residuals procedure was developed to estimate the mechanical behavior for a coated fuel particle (CFP) of a high temperature gas-cooled reactor (HTGR). Through a weak formulation, finite element equations for multiple layers were set up to calculate the displacements and stresses in a CFP. The finite element method was applied to the stress analyses for three coating layers of a tri-isotropic coated fuel particle (TRISO) of a HTGR. The stresses calculated by the finite element method were in good agreement with those from a previously developed computer code and depicted the typical stress behavior of the coating layers very well. The newly developed finite element method performs a stress analysis for multiple bonded layers in a CFP by changing the material properties at any position in the layers during irradiation.

Performance-based seismic design of eccentrically braced steel frames using target drift and failure mode

  • Li, Shen;Tian, Jian-bo;Liu, Yun-he
    • Earthquakes and Structures
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    • 제13권5호
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    • pp.443-454
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    • 2017
  • When eccentrically braced steel frames (EBFs) are in the desired failure mode, links yield at each layer and column bases appear plastically hinged. Traditional design methods cannot accurately predict the inelastic behavior of structures owing to the use of capacity-based design theory. This paper proposes the use of performance-based seismic design (PBSD) method for planning eccentrically braced frames. PBSD can predict and control inelastic deformation of structures by target drift and failure mode. In buildings designed via this process, all links dissipate energy in the rare event of an earthquake, while other members remain in elastic state, and as the story drift is uniform along the structure height, weak layers will be avoided. In this condition, eccentrically braced frames may be more easily rehabilitated after the effects of an earthquake. The effectiveness of the proposed method is illustrated through a sample case study of ten-story K-type EBFs and Y- type EBFs buildings, and is validated by pushover analysis and dynamic analysis. The ultimate state of frames designed by the proposed method will fail in the desired failure mode. That is, inelastic deformation of structure mainly occurs in links; each layer of links involved dissipates energy, and weak layers do not exist in the structure. The PBSD method can provide a reference for structural design of eccentrically braced steel frames.

Study on slope stability of waste dump with a weak layer using finite element limit analysis method

  • Chong Chen;Huayong Lv;Jianjian Zhao;Zhanbo Cheng;Huaiyuan Wang;Gao Xu
    • Structural Engineering and Mechanics
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    • 제89권3호
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    • pp.253-263
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    • 2024
  • Slope stability is generally paid more attention to in slope protection works, especially for slope containing weak layers. Two indexes of safety factor and failure model are selected to perform slope stability. Moreover, the finite element limit analysis method comprehensively combines the advantage of the limit analysis method and the finite element method obtaining the upper and lower bounds of the safety factor and the failure mode under the slope stability limit state. In this study, taking a waste dump containing a weak layer as an engineering background, the finite element limit analysis method is adopted to explore the potential failure mode. Meanwhile, the sensitivity analysis of slope stability is performed on geometrical and geotechnical parameters of the waste dump. The results show that the failure mode of the waste dump slope is two wedges if the weak layer is located on the ground surface (Model A), while the slope can be observed as three wedges failure if the weak layer is below the ground surface (Model B). In addition, both failure modes are highly sensitive to the friction angle of the weak layer and the shear strength of waste disposal, and moderately sensitive to the heap height, the dip angle and cohesion of the weak layer, while the toe cutting has limited effect on the slope stability. Moreover, the sensitivity to the excavation of the ground depends on the location of the weak layer and failure mode.

Compressible Boundary Layer Stability Analysis With Parabolized Stability Equations

  • Bing, Gao;Park, S.O.
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2006년도 추계 학술대회논문집
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    • pp.110-119
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    • 2006
  • An accurate and cost efficient method PSE is used for the stability analysis of 2D or 3D compressible boundary layers. A highly accurate finite difference PSE code has been developed at a general curvilinear coordinate system using an implicit marching procedure to deal with a broad range of transition predictions problems. Evolution of disturbances in compressible flat plate boundary layers are studied for free-stream Mach numbers ranging from 0 to 1.5. The effect of mean-flow nonparallelism is found to be weak on two dimensional waves and strong on three dimensional waves. The maximum amplification rate increases monotonically with Mach number. The present PSE solutions are compared with previous numerical investigations and experimental results and are found to be in good agreement.

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Fracture Behavior of Silicon Nitride-silicon Carbide-boron Nitride Multi-layer Composites with Different Layer Thickness

  • Cho, Byoung-Uk;Park, Dong-Soo;Park, Hong-Chae
    • 한국세라믹학회지
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    • 제39권7호
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    • pp.622-627
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    • 2002
  • Multi-layer composites consisting of silicon nitride, silicon nitride-silicon carbide and boron nitride-alumina layers were prepared fly stacking the corresponding ceramic tapes. The composites demonstrated self-diagnostic capability and non-catastrophic failure behavior. The composites consisting of many thin layers exhibited high strength and stepwise increase of the electrical resistance during the flexure test. The strength of the composite with too thick silicon nitride layers was low and the electrical resistance was abruptly increased to the detection limit of the digital multi-meter during the test. An extensive crack branching was observed in the weak (BN + Al$_2$O$_3$)layer.

Ideal structure for tunneling magnetoresistance and spin injection into semiconductros: Ni(111)/BN/Co(111)

  • Arqum, Hashmi;Son, Jicheol;Hong, Jisang
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2013년도 자성 및 자성재료 국제학술대회
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    • pp.32-32
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    • 2013
  • Using the Vienna ab initio simulation package (VASP) incorporating van der Waals interaction, we have explored structural, adsorption, and magnetic properties of Ni(111)/BN/Co(111) systems. We have found that both Ni(111) and Co(111) layers shows half metallic state, while the spacer BN layer becomes weak metal for one monolayer (ML) thickness and an insulating barrier for two ML thickness. The half metallic states in both Ni(111) and Co(111) layers are robust because it is unchanged independently on the magnetic coupling of Ni(111) and Co(111). This finding suggests that the Ni(111)/BN/Co(111) systems can be utilized for perfect tunneling magnetoresistance system. Moreover, it can be applied for potential spin injecting into semiconductor in FM/semiconductor system due to the fact that the half metallic state in FM layers at the interface will be unchanged.

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