• 제목/요약/키워드: geophysics

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Construction of calibration models and calibrating experiment for efficient Held application of density log (밀도검층의 효과적인 현장 적용을 위한 모형 보정공 건설과 밀도 보정 기초연구)

  • Kim Ji-hoon;Kong Nam-young;Zhao Weijun;Kim Yeong-hwa
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.09a
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    • pp.73-82
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    • 2005
  • We constructed a series of calibration models in the campus of Kangwon National University. A series of experiment for calibrating sonde response as well as casing effect in field measurement. Here we explained the process of construction of calibrating facility which consists of three model holes of different density and three model holes of different diameter. It was discussed the calibration equations obtained from its sonde response calibration test. A density correction chart for different separation of detector from hole wall was suggested, and verified the possibility of determining true density from measurements in cased hole.

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Automatic Extraction of Building Heights from Aerial Digital Images

  • Yom, Jae-Hong;Lee, Dong-Cheon;Kim, Jeong-Woo;Kwon, Jay-Hyon;Kim, Deok-In
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.517-517
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    • 2002
  • Recently in the field of telecommunication, there is much interest in geo-surface characteristics of urban areas. Geophysical properties of urban features are now incorporated with accurate positional information to model the telecommunication environment. In this study, three-dimensional buildings are geometrically reconstructed from existing vector maps and aerial images. Accurate digital vector maps are easily available in Korea. However existing maps, which had been produced for GIS applications, do not have height information which is critical to three dimensional building reconstruction. Image matching techniques were applied to aerial image stereopairs to automatically extract the height information of buildings. Planimetric coordinates from vector maps were used as initial guides in the process. Future studies will be undertaken to link geophysical properties to the three-dimensional spatial objects reconstructed from this study thus bringing the telecommunication environment model closer to reality.

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Integration of Geophysical Properties and Geospatial Information for Telecommunication Modeling

  • Kim, Jeong-Woo;Lee, Dong-Cheon;Pack, Jeong-Ki;Yom, Jae-Hong;Kwon, Jay-Hyon;Jeong, Nam-Ho
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.745-745
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    • 2002
  • Both geophysical and geospatial data provide important information in the establishment of the optimal telecommunication systems especially in the mobile telecommunication environment. The objective of this study is to utilize geophysical properties and geospatial information in the analysis of the telecommunication environment through point-to-point wave property modeling. Geophysical properties associated with wave propagation parameters of the earth surface were analyzed based on hierarchical land classification using Landsat ETM+ and IKONOS images. Three-dimensional geospatial information was obtained by processing stereo aerial images. The results show that the accurate geospatial information and reliable geosphysical property of the surface improve the prediction of receiving power of the receivers located near corners of the buildings where diffractions occur. The wave property model developed from accurate telecommunication environment could be applied to optimal cell planning and delay time analysis.

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Geophysics of Vowel Space in Bahasa Malaysia and Bahasa Indonesia (말레이시아어와 인도네시아어 모음 공간의 지형도)

  • Park Han-Sang;Park Jeong-Sook;Chun Tai-Hyun
    • MALSORI
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    • no.58
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    • pp.19-34
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    • 2006
  • The present study investigates the vowels of Bahasa Malaysia and Bahasa Indonesia in terms of the first two formant frequencies and provides a three-dimensional formant chart of vowels by plotting F1, F2, and the frequency of datapoints on 4 different scales: Hz, mel, bark, and the number of ERB. For this study, we recruited 30 male native speakers of Bahasa Malaysia and Bahasa Indonesia (15 each) which include 6 vowels (i, e, a, o, u, e) in various contexts. The three-dimensional formant chart showed geophysics of vowel space, such that mountain peaks stand in particular locations with a higher frequency of occurrence of datapoints. The geophysics of vowel space may shed lights on the perceptual structure of vowel space. The results also showed that vowels in utterance-final positions have a significantly higher F1 and a significantly lower F2 than those in utterance-medial or utterance-initial positions, which means that vowels in utterance-final positions are more back and lower in vowel space than those in utterance-medial or utterance-initial positions.

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A Study on the 2-D distribution of Dynamic Poisson's Ratio using 3-C Geophones (3성분 지오폰을 이용한 동포아송비의 2차원 분포 연구)

  • Hong, Myung-Ho;Hwang, Yoon-Gu;Cho, Cheol-Hee;Lee, Yoon-Jung;Kim, Ki-Young
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.05a
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    • pp.223-226
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    • 2005
  • In order to acquire 3 components data which has the good signal to noise ratio with only one shot, 3-C geophones were used, As a result, the vertical component showed the distinct first arrival of P-wave, and the horizontal component was improved the signal to noise ratio of S-wave, while was attenuated P-wave. The 2-D Poisson's ratio section was computed from P- and S-wave cell velocities included velocity tomograms of the P- and S-waves. The Poisson's ratio values were computed in the range of $0.2{\~}0.3$. With one shot, we can obtain 2-D distribution of dynamic Poisson's ratio as well as velocity tomograms of P- and S-waves.

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Resistivity Survey Using Long Electrodes (긴 전극을 사용하는 전기비저항 탐사)

  • Cho, In-Ky;Lee, Keun-Soo;Kim, Yeon-Jung;Kim, Rae-Young
    • Geophysics and Geophysical Exploration
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    • v.19 no.1
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    • pp.45-50
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    • 2016
  • Generally, a point source has been routinely used in the electrical resistivity measurements because of easy installation. If steel-cased wells are used as long electrodes, we can expect the better depth of investigation. However, the resistivity data with long electrodes can not be processed with a conventional inversion algorithm because a long electrode produces the different primary potential distribution compared with the point source. In this study, we proposed a new technique to process the electrical resistivity data with long electrodes by replacing the long electrode with a sequence of point electrodes. Comparing the potentials obtained from the technique with the analytic/numerical solution, we ensure that the proposed technique can be used for the numerical resistivity modeling based on the finite difference or finite element method.