• Journal of the Korean Society of Groundwater Environment
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• v.1 no.2
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• pp.73-79
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• 1994

1957년 인류중 처음 외계로부터 지구를 바라본 소련의 우주비행사 가가린은"지구는 푸르다"라고 말했다. 이 우주에는 무수한 행성이 있지만 그중에서 단 하나 지구만이 그 표면에 가득히 물을 저장하고 있다. 따라서 지구를 물의 행성이라고도 한다. 그런데 어째서 지구에만 물이 존재하며, 그 물의 기원은 무엇인가. Table 1에 지구 수권에 있어서의 물의 분포가 표시되어 있다. 이를 보면 지구상의 물의 중요도는 해양, 만년빙 또는 빙하 그리고 지하수의 순임을 알 수 있다. 따라서 우리들은 육지에 있어서 지하수의 중요성을 다시 인식해야 할 것이다.식해야 할 것이다.

• Aerospace Industry
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• s.105
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• pp.48-49
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• 2009

21세기 최대 화두는 바로 환경문제. 극지방의 빙하가 녹아 사라지고 기상이변으로 인한 자연재해 빈도가 급증함에 따라 이제 환경문제는 먼 미래가 아닌 바로 오늘의 문제로 인식되고 있다. 환경문제가 대두되면서 항공 산업분야 역시 현실적인 친환경 계획을 속속 발표하고 실천에 옮기고 있다. 그 중에서도 가장 눈에 띄는 것이 바로 퇴역 항공기의 재활용 프로젝트다. 퇴역과 동시에 고절 취급을 받는 항공기를 어떻게 재활용 하겠다는 것인지 관련 기술에 대해 알아본다.

• Journal of the KSME
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• v.44 no.7
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• pp.14-17
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• 2004

지난달부터 상영 중인 영화 ‘Tomorrow(원제 : The Day After Tomorrow)’ 는 이상기후라는 색다른 주제를 다루고 있다. 기상 이변으로 지구 북반구 전체에 빙하기가 시작되어 인류가 최악의 위기를 접하게 된다는 설정의 블록버스터 재난 영화이다. 이상기후현상과 관련하여 가장 심각하게 인식되고 있는 것이 바로 지구온난화일 것이다. 지구온난화라는 말이 학술적으로 사용되기 시작한 지 그리 오래되지 않았음에도 불구하고 현재 대부분의 사람들이 이 용어에 친숙해 있는 것은 그만큼 이러한 지구온난화현상의 심각성에 대해 폭넓게 이해하고 있다는 것을 의미할 것이다.(중략)

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.27 no.5
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• pp.461-470
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• 1998

"인류가 물 관리를 이렇게 하다가는 2025년경 심각한 문제가 생긴다."라고 유엔이 98년 3월 22일 "세계 물의 날"을 맞아 이렇게 경고했다. 지구상의 물은 97% 이상이 소금물이고 2.5% 정도만 민물, 민물의 1/3은 지하 대수층에서 얻어진다. 나머지는 빙하와 만년설, 강에서 충당된다. 전 세계는 지하수의 60%를 사용중이며 선진국에서 이 가운데 20~40%를 쓴다. 세계기상기구(WMO)는 "지하수는 자연적으로 채워지는 속도보다 훨씬 빠르게 고갈되고 있다"며 세계 58억 인구의 1/5이 먹을 물이 부족하고 절반 이상이 적절한 위생시설이 없다."고 우려하고 있다.반 이상이 적절한 위생시설이 없다."고 우려하고 있다.고 있다.

• Journal of the Korean Geographical Society
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• v.33 no.3
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• pp.377-394
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• 1998

The magnetic record of loess deposits may be one of the most detailed and useful records of Quatermary climate change on the continents. Stratigraphic variations of magnetic parameters define alternating zones of high and low concentrations of magnetic minerals. All the concentration-sensitive magnetic parameters show an increase within the interstadial Gilman Canyon Formation and interglacial Brady soil and a systematic decrease within the Wisconsinan Peoria loess. The influence of climate change on magnetic records is confirmed by a high correlation between the magnetic parameters and biological proxies. Rock magnetic data appear to be better correlated with temperature-sensitive biological proxies than does a precipitation-sensitive index such as the aridity index derived from opal phytoliths. Simultaneous, higher resolution sampling of magnetic and biological proxies proved to be a better sampling tactic, and enhanced the feasibility of rock magnetic parameters as independent climate proxies.

• Journal of Ocean Engineering and Technology
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• v.28 no.2
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• pp.126-132
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• 2014

In this study, a method for analyzing the collision and interaction between ice bergy bits and a Mark III type liquid natural gas (LNG) carrier was considered, and the structural safety of a ship's hull and cargo containment system (CCS) was evaluated. In the analysis, a constitutive model implementing the strain rate dependant mechanical property was used to consider the typical material characteristics of ice rationally. A relatively simple and easy ice structure interaction analysis procedure, compared with the accurate but complicated FSI analysis scheme, was suggested. When the ice bergy bits collided with ship's side hull under the four assumed scenarios, the structural behaviors of the ship structure and LNG CCS were simulated by applying the suggested ice collision analysis procedure using the commercial hydro-code LS-DYNA. In addition, the effects of the shapes and colliding speed of the ice bergy bits on the ice-structure interaction and safety of the CCS were examined in detail.

• Journal of the Korean earth science society
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• v.26 no.6
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• pp.541-550
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• 2005

Molluscan shells were sampled from the continental shelf of South Sea: 19 stations in the southeast continental shelf and 5 in the southwest sea, in order to understand characteristics of sea level changes and time-averaging since the last glacial age. Radiocarbon dates were made on 42 dominant and specific species which were sampled from 24 stations. Time-averaging was observed and showed to be 11,939 years in age difference. The sea-level ranged from 150 to 160 m below sea level during the LGM (about 15,000 yrs B.P). The sea-level significantly rose to 60 m at around 9,000 yrs B.P. and became stable at 50 to 60 m between periods between 4,000 and 5,000 yrs B.P. Between 3,000 and 4,000 yrs B.P, the sea-level rapidly rose to a depth of $10\~20m$ below today’s present sea level.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.3
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• pp.375-384
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• 2009

The GRACE satellite, Launched in March 2002, is applied to research on glacial melt of polar regions, glacial isostatic adjustment(GIA), sea level change, terrestrial water storage(TWS) variation of river basin and large-scale earthquake etc. In this research, the TWS variation of Yangtze river basin from August, 2002 to January, 2009 is analyzed using Level-2 GRACE monthly gravity field model. Particularly, gravity changes of the Three Gorges Dam during the impoundment process in 2003, 2006 and 2008 is observed by estimating equivalent water thickness(EWT). The research results show the distinct annual and seasonal changes of Yangtze river basin, and its amplitude of annual variation is 2.3cm. In addition, we compare the results with water resource statistics and hydrologic observation data to confirm the possibility of research of TWS variation of river basin using GRACE observation data, and also the satellite gravity data is of great help for the research on the movement and periodic changes of river basin.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.2
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• pp.85-91
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• 2016

The most important factor in the structural design of ships and offshore structures operating in arctic region is ice load, which results from ice-structure interaction during the ice collision process. The mechanical properties of ice related to strength and failure, however, show very complicated aspect varying with temperature, volume fraction of brine, grain size, strain rate and etc. So it is nearly impossible to establish a perfect material model of ice satisfying all the mechanical characteristics completely. Therefore, in general, ice collision analysis was carried out by relatively simple material models considering only specific aspects of mechanical characteristics of ice and it would be the most significant cause of inevitable errors in the analysis. Especially, it is well-known that the most distinctive mechanical property of ice is high dependency on strain rate. Ice shows brittle attribute in higher strain rate while it becomes ductile in lower strain rate range. In this study, the simulation method of ice collision to ship hull using the nonlinear dynamic FE analysis was dealt with. To consider the strain rate effects of ice during ice-structural interaction, strain rate dependent constitutive model in which yield stress and hardening behaviors vary with strain rate was adopted. To reduce the huge amount of computing time, the modeling range of ice and ship structure were restricted to the confined region of interest. Under the various scenario of ice-ship hull collision, the structural behavior of hull panels and failure modes of ice were examined by nonlinear FE analysis technique.

• Journal of Ocean Engineering and Technology
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• v.9 no.2
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• pp.156-166
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• 1995

Regrading the development of offshore natural gas field near Sakhalin Island which is an ice-infested area, this study aims to estimate the dynamic ice load for construction of offshore structures operating in this region. In this paper the design ice load and dynamic responses of a slender Arctic structure upon continuous ice movement are sutdied. Crushing agter a certain elastic deformation is assumed as a primary failure mechanism at the contact zone between semi-infinite level ice edge and the face of structure. Dynamic interaction forces are calculated using a modified Korzhavin's equation and a two-dimensional ice-structure interaction model is adopted. To verify the numerical model, dynamic analysis is performed for on of the Baltic Sea channel markers whose response patterns were presiously observed.