• Title/Summary/Keyword: 정착성

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Analysis of Annual Variability of Landfast Sea Ice near Jangbogo Antarctic Station Using InSAR Coherence Images (InSAR 긴밀도 영상을 이용한 남극 장보고기지 인근 정착해빙의 연간 변화 분석)

  • Han, Hyangsun;Kim, Yeonchun;Jin, Hyorim;Lee, Hoonyol
    • Korean Journal of Remote Sensing
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    • v.31 no.6
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    • pp.501-512
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    • 2015
  • Landfast sea ice (LFI) in Terra Nova Bay, East Antarctica where the Jangbogo Antarctic Research Station is located, has significant influences on marine ecosystem and the sailing of an icebreaker. Therefore, it is essential to analyze the spatio-temporal variation of the LFI in Terra Nova Bay. In this study, we chose interferometric pairs with the temporal baseline from 1 to 9 days out of a total of 62 COSMO-SkyMed synthetic aperture radar (SAR) images over Terra Nova Bay obtained from December 2010 to January 2012, and then constructed the coherence image of each pair. The LFI showed coherence values higher than 0.3 even in the interferometric SAR (InSAR) pairs of up to 9-days of temporal baseline. This was because the LFI was fixed at coastline and thus showed low temporal phase decorrelation. Based on the characteristics of the coherence on LFI, We defined the areas of LFI that show spatially homogeneous coherence values higher than 0.5. Pack ice (PI) and open water showed low coherence values due to large temporal phase decorreation caused by current and wind. Distinguishing PI from open water in the coherence images was difficult due to their similarly low coherence values. PI was identified in SAR amplitude images by investigating cracks on the ice. The extents of the LFI and PI were estimated from the coherence and SAR amplitude images and their temporal variations were analyzed. The extent of the LFI increased from March to July (maximum extent of $170.7km^2$) and decreased from October. The extent of the PI increased from February to May and decreased from May to July when the LFI increases dramatically. The extent of the LFI and air temperature showed an inverse correlation with a time lag of about 2 months, i.e., the extent of the LFI decreases after 2 months of the increase in the air temperature. Meanwhile the correlation between wind speed and the extent of the LFI was very low. This represents that the extent of LFI in Terra Nova Bay are influenced more by the air temperature than wind speed.

Study on the Legal Establishment of u-City Management Center (u-City 통합운영센터의 제도적 정착방안에 관한 연구 - 정의 및 위상을 중심으로 -)

  • Cho, Chun-Man;Kim, Jung-Hoon
    • Spatial Information Research
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    • v.17 no.1
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    • pp.15-23
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    • 2009
  • For the development and management of u-City(ubiquitous city), Ubiquitous City Construction Law was enacted(March 3, 2008) to form the legal basis of u-City plan, construction and managements afterwards. Among u-City elements, the u-City Management Center has its own meaning and importance in roles which are crucial to the u-City developments, and its legal establishment is one of the core u-City realization factors. In spite of its crucial position for u-City, the legal arrangement of its basis concept, physical/systematic structures, and managerial finance sources and their standardizations are very immature. Therefore, the purpose of this study is to analyse its overall problem issues and then to suggest the basic directions and enforcement strategies to form its legal basis.

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A Study on the Physical Behavior and the Applicability of Rock Anchorage System of a Suspension Bridge in Domestic Island (현수교 지중정착식 앵커리지의 거동특성과 국내 도서지역에서의 적용성에 대한 연구)

  • Yang, Euikyu;Choi, Youngseok;Choi, Kyungseob;Kim, Daehak;Jeon, Yongjun
    • Journal of the Korean Geotechnical Society
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    • v.37 no.2
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    • pp.33-48
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    • 2021
  • The rock anchorage of a suspension bridge is an outstanding anchorage type from environmental and economical perspective, although it should be applied when the bearing foundation is fresh enough to resist large cable loads. In practice, geotechnical engineers have encountered difficulties in designing the anchorage structure due to the fact that the physical behaviors of rocks against cable loads have not yet been fully proved and its design method was not established yet. In this study, model tests and numerical studies were performed to evaluate the behavior of the rock anchorage system planned under hard rock layers in domestic islands, and results suggest that the shape of asymmetric rock wedges can resist the tension loads with self weight and shear resistance. Additionally, real scale trial tests were carried out to verify the accuracy of an inclined drilling penetrating hard rock layers to install tendon to the bearing plate.