• Title/Summary/Keyword: 역대합

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Enhanceement of Vertical Resolution of GPR data through Signature Deconvolution (신호파형 역대합을 통한 지중레이다 자료의 수직해상도 향상)

  • Kim, Gi-Yeong;Son, Ho-Ung;Lee, Ju-Han;Hong, Myeong-Ho
    • Journal of the Korean Geophysical Society
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    • v.9 no.1
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    • pp.1-6
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    • 2006
  • To remove ringing and increase vertical resolution of GRP data, signature deconvolution was applied to GPR data obtained using a 100 MHz antenna in the Soyang Lake. The signature was extracted through stacking reflection signals from the lake bottom. Results of this deterministic deconvolution was compared with those from the conventional Wienner method. Due to increased vertical resolution, both deconvolution methods are able to resolve three or more layers in an apparent single layer on the input data. However, identification of reflection boundaries from ringing is not easy due to poor definition in the output data of the Wienner filter. On the contrary, the signature deconvolution greatly enhances both vertical resolution and definition of reflection boundaries, showing detailed internal stratigraphic features of the three sedimentary layers. Since extraction of signature at various depths is possible, this deconvolution method can be appled effectively to unstationary GPR data.

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A Study on the Introduction and Explanation of the sum of the Angles of a Triangle in Elementary School Mathematics (초등학교 수학에서 삼각형의 내각의 합의 도입과 설명 방법)

  • Hong, Gap ju;Oh, Seong hun
    • Education of Primary School Mathematics
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    • v.21 no.1
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    • pp.75-91
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    • 2018
  • This study examines the educational meaning of the sum of the angles of a triangle in elementary school mathematics and discusses the introduction and explanation methods to convey the meaning faithfully. First, we investigated how to introduce the sum of the angles of a triangle in the Korean national mathematics curriculums from the past to the present and surveyed the experiences and opinions of the teachers. The results of the survey are summarized and discussed in three parts: The context of 'arranging angles activities' and 'measuring angles activities', the methods to convey the meaning of the sum of the angles of a triangle as an invariance, and other details.

The Study of Writer Who Wrote a Dongmongseonseup ("동몽선습(童蒙先習)"의 저자(著者)에 관한 연구(硏究))

  • Yoo, Boo-Hyeon
    • Journal of Korean Library and Information Science Society
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    • v.40 no.3
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    • pp.389-402
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    • 2009
  • This study is focused on finding a clue that can establish a sound argument about who the writer of Dongmongseonseup was. Several significant materials that hadn't been examined before were studied so now is examined more specific. The conclusion is that Dongmongseonseup was a collaboration between Park Se-Mu and Min Je-In. Park Se-Mu wrote the moral rules to govern the Five Human Relations that is the part of the Kyeong, the first part of Dongmongseonseup. Min Je-In wrote the last part of it, the historical work Yeokdaeyoui, and then put the two works together.

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Helicopter-borne and ground-towed radar surveys of the Fourcade Glacier on King George Island, Antarctica (남극 킹조지섬 포케이드 빙하의 헬리콥터 및 지상 레이다 탐사)

  • Kim, K.Y.;Lee, J.;Hong, M.H.;Hong, J.K.;Shon, H.
    • Geophysics and Geophysical Exploration
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    • v.13 no.1
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    • pp.51-60
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    • 2010
  • To determine subglacial topography and internal features of the Fourcade Glacier on King George Island in Antarctica, helicopter-borne and ground-towed ground-penetrating radar (GPR) data were recorded along four profiles in November 2006. Signature deconvolution, f-k migration velocity analysis, and finite-difference depth migration applied to the mixed-phase, single-channel, ground-towed data, were effective in increasing vertical resolution, obtaining the velocity function, and yielding clear depth images, respectively. For the helicopter-borne GPR, migration velocities were obtained as root-mean-squared velocities in a two-layer model of air and ice. The radar sections show rugged subglacial topography, englacial sliding surfaces, and localised scattering noise. The maximum depth to the basement is over 79m in the subglacial valley adjacent to the south-eastern slope of the divide ridge between Fourcade and Moczydlowski Glaciers. In the ground-towed profile, we interpret a complicated conduit above possible basal water and other isolated cavities, which are a few metres wide. Near the terminus, the GPR profiles image sliding surfaces, fractures, and faults that will contribute to the tidewater calving mechanism forming icebergs in Potter Cove.

Effect of Bond Action of Longitudinal Bars on Shear Transfer Mechanism in RC Beams (RC 보에서의 전단저항기구와 주철근의 부착 작용과의 관계)

  • Kim Kil-Hee
    • Journal of the Korea Concrete Institute
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    • v.17 no.4 s.88
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    • pp.513-520
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    • 2005
  • The uniform truss mechanism is widely accepted as a shear transfer mechanism in reinforced concrete members. However, the uniform truss action cannot be expected when the bond stress distribution is not constant along longitudinal bars. A test method in which only the truss action takes place is developed and conducted to investigate the truss actions under various bond contributions. Based on the experimental results and analysis, the following findings can be obtained: 1) The bond stress distribution depends on the axial compression force, the amount of shear reinforcement and loading conditions. 2) The analysis using the combined truss model consisting of uniform and fan-shape trusses can predict the experimental results