• Title/Summary/Keyword: Ground observation

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The Application of Observational Method for Tunnel Analysis in Gneiss Rock (편마암에서 계측결과와 RMR을 이용한 터널의 거동 연구)

  • Jeong, Kang-Jin;Kim, Chan-Kuk;Hwang, Eui-Seok;Kim, Hak-Moon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.916-924
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    • 2006
  • This research concentrates on presenting a more reasonable and engineering tunnel interpretation method with the numerical value observation data using the Hoek-Brown Model that uses mining observation data gained during construction, and the experience material constant of m and s for Seoul Underground tunnel field, which was evaluated as RMR III and RMR IV for its bedrock ratings, and by modifying and complementing the properties of ground materials with the direct method, one method in back analysis, and by using the field measurement value.

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동남해안지역의 피압단열 대수층에서 조석 분석법을 이용한 수리상수 추정

  • 심병완;정상용;성익환;이병대;조병욱
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.497-500
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    • 2003
  • If ground water levels of a confined fractured rock aquifer fluctuate with sea tides, individual values of hydrogeologic parameters can be determined. Tidal efficiency and time lag are first calculated from the water level data recorded at an observation device situated inland from the sea. The tidal efficiency factor of the aquifer at the seacoast is then determined from the observation in monitoring wells and used to calculate storage coefficient. Tidal efficiency factor and the tidal time lag are utilized to calculate storage coefficient and the results are compared. This method is tested in the southeastern coastal area of Busan, Korea. This is a simple and inexpensive way to test confined aquifer but the analysis should be performed according to the coastal environment.

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Effects of Rock Weathering on the Degradation of Engineering Properties (암반풍화도에 따른 지질공학적 특성 저감효과)

  • Lee Chang-Sup;Cho Taechin
    • Tunnel and Underground Space
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    • v.15 no.6 s.59
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    • pp.411-424
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    • 2005
  • Weathering is defined as a process by which surface rock, once formed in the deep ground, is broken down and altered to keep the equilibrium with the ambient environment. In this study granitic rock samples of different weathering grades were collected in the field and the microscopic observation, X-ray diffraction analysis, electron microscopic observation, chemical analysis, and rock property tests were carried out. Formation of secondary minerals, especially clay minerals, by weathering was identified and the mechanism for the change of engineering properties such as rock strength degradation was analyzed. Tunnel model test, Failure behaviour, Shallow tunnel, Unsupproted tunnel length.

The consideration about prevention ways of discovery of emergency situation which is based on guard techniques (경호기법에 의한 위급상황의 발견과 대처 방안에 관한 고찰)

  • Gong, Bae-wan
    • Journal of the Society of Disaster Information
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    • v.6 no.2
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    • pp.11-20
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    • 2010
  • All of the people or objects which are contacted during the activity of guard are added to range of objects. guard has to notice decision, question proposal, observation, accomplish to be happened them at the same time recognizing the steps as soon as possible. Before a lot of information of client are shown, guard expert has to search observation of materialization, extension of reservation, notification of business and causes of danger through personal interviews. Rapid communication system has to be assumed and effective caution, protection and shelter and following prevention are cooperated as well as has to care about safe of guard object by a protective wall. And also has to get out of the ground, keep the large shape when moves, prevent the trials of attack from the assassinators after takeing control over weapons.

A Study on the Verifying Structural Safety of Satellite Structure by Coupled Load Analysis (열변형으로 인한 인공위성 관측장비 지향오차 연구)

  • Kim, Sun-Won;Hyun, Bum-Seok;Kim, Chang-Ho;Hwang, Do-Soon
    • Journal of Satellite, Information and Communications
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    • v.5 no.1
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    • pp.75-79
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    • 2010
  • Satellite structure is distorted by thermal load in orbit. The structural distortion induces the pointing errors of observation unit that is difference between initial pointing direction at ground integration and at in-orbit. In that case, satellite is not able to point along required direction. As observation capability becomes higher, structural distortion due to thermal load should be smaller to achieve successful mission. In this paper, the method to predict pointing error and results are described.

Vulnerability assessment of residential steel building considering soil structure interaction

  • Kailash Chaudhary;Kshitij C. Shrestha;Ojaswi Acharya
    • Earthquakes and Structures
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    • v.25 no.2
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    • pp.79-87
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    • 2023
  • Special moment resisting steel frame structures are now being used commonly in highly seismic regions as seismically reliable structures. However, a very important parameter describing the dynamics of steel structures during earthquake loading, Soil Structure Interaction (SSI), is generally neglected. In this study, the significance of consideration of flexibility of soil in being able to obtain a result closer to reality is asserted. The current paper focuses on calculation of seismic fragility curves special moment resisting steel frame structures under different earthquake loadings for fixed-base and SSI models. The observation of obtained fragility curves lead to the conclusion that the SSI has a considerable effect on component fragility for the steel structures, with its effects decreasing for higher peak ground acceleration. The results show that the structures when considered SSI have a higher probability of exceeding a damage limit state. This observation attests the role of SSI in the accurate study of structural performance.

Visibility Estimated from the Multi-wavelength Sunphotometer during the Winter 2011 Intensive Observation Period at Seoul, Korea (2011년 겨울철 서울시 대기 집중 관측 기간 동안 다파장 복사계로 분석된 에어러솔 연직분포와 시정 거리)

  • Lee, Kwon-Ho;Kim, Kyung-Won;Kim, Gwanchul;Jung, Kweon;Lee, Soon-Hee
    • Journal of Korean Society for Atmospheric Environment
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    • v.29 no.5
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    • pp.682-691
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    • 2013
  • The aerosol extinction vertical profile and surface visibility have been derived from the Microtops-II sunphotometer observation during the winter 2011 intensive observation period (IOP) at Seoul, Korea. Using models of degradation of aerosol optical thickness (AOT) and aerosol scale height, we have performed extinction-visibility modulation to determine the height dependent aerosol extinction and visibility. It is shown that the aerosol loading is relatively low during IOP (mean $AOT_{550}=0.22{\pm}0.08$, ${\AA}$ngstr$\ddot{o}$m exponent=$1.14{\pm}0.26$). Modeled extinction by use of Microtops II sunphotometer data shows good agreement with measurements by the Multi-wavelenth Polarization Lidar (MPoLAR), and the derived surface visibility are consistent with data from the transmissometer. These results emphasize the use of a vertically resolved extinction from AOT to predict visibility conditions at ground level.

MTF Measurement for Flight Model of MAC, a 2.5m GSD Earth Observation Camera (2.5m 해상도 지구관측 카메라 MAC 비행모델의 지상 MTF 성능 측정)

  • Kim, Eugene-D.;Choi, Young-Wan;Yang, Ho-Soon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.10
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    • pp.98-103
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    • 2005
  • The Flight Model of MAC (Medium-sized Aperture Camera), a 2.5m GSD class earth observation camera has been aligned and assembled. Topics discussed in this paper include the ground MTF performance of the MAC system, and the alignment of the focal plane assembly. MTF was measured by a knife-edge scanning technique, and a 450 mm diameter Cassegrain collimator with diffraction-limited performance was made and used for the MTF measurements. System MTF was used as the figure-of-merit to find the best focus of the focal plane assembly.

DEFORMATION OF AUGUSTINE VOLCANO, ALASKA, 1992-2006, MEASURED BY ERS AND ENVISAT SAR INTERFEROMETRY

  • Lee, Chang-Wook;Lu, Zhong;Kwoun, Oh-Ig
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.582-585
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    • 2006
  • Augustine volcano is an active stratovolcano located southwest of Anchorage, Alaska. Augustine volcano experienced seven significantly explosive eruptions in 1812, 1883, 1908, 1935, 1963, 1976, and 1986, and a minor eruption in January 2006. To measure ground surface deformation of Augustine volcano, we applied satellite radar interferometry with ERS-1/2 and ENVISAT SAR images acquired from three descending and three ascending satellite tracks. Multiple interferograms are stacked to reduce artifacts due to changes in atmospheric condition and retrieve temporal deformation sequence. For this, we used Least Square (LS) method for reducing atmospheric effects and Singular Value Decomposition (SVD) method for the retrieval of a temporal deformation sequence. Interferograms before 2006 eruption show about 3 cm/year subsidence by contraction of pyroclastic flow deposits from the 1986 eruption. Interferograms during 2006 eruption do not show significant deformation around volcano crater. Interferograms after 2006 eruption show again a several cm subsidence by compaction and contraction of pyroclastic flow deposits for a few months. This study demonstrates that satellite radar interferometry can monitor deformation of Augustine volcano to help understand the magma plumbing system driving surface deformation.

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Evaluation of Phase Calibration Performance with KVN

  • Jung, Dawoon;Sohn, Young-Jong;Byun, Do-Young;Jung, Taehyun
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.36.2-36.2
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    • 2016
  • In mm-VLBI, the quality of observation data is largely affected by atmospheric effect. The most challenging matter is that the phase of correlator output fluctuates rapidly resulting from a variation of atmospheric propagation delay. Consequently, it is demanding to achieve high Signal-to-Noise ratio by integrating data in time domain before calibrating atmospheric delay. However, Korean VLBI Network (KVN) has a unique system to make a 4-frequency (22/43/86/129 GHz) simultaneous observation in mm-wavelength and Frequency Phase Transfer (FPT) calibration technique has effectively removed atmospheric delay in the simultaneous multi-frequency observation of the KVN. For astrometric and astrophysical studies, we evaluated the FPT performance of KVN in various observing conditions. Using the total 38 bright AGNs, we have compared atmospheric conditions such as ground-based weather information, system temperature, atmospheric delay with the calibration results of FPT at 22/43/86/129 GHz during the five experiments in 2013, and quantified its performance in terms of coherence function and Allan variance. We present the analysis result of the relation between the FPT performance and observing conditions.

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