• 수산해양기술연구
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• 제56권4호
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• pp.322-339
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• 2020

Temporal and spatial fluctuations of surface water temperature in Yeosu Bay for the period from 2010 to 2011 were studied using the data from temperature monitoring buoys deployed at 32 stations in the south coast of Korea. Temperatures in the northern part of the bay are higher in summer and lower in winter than in the southern part of the bay. The lowest and highest temperature of the annual mean are found at the eastern coast of POSCO and at the west of Dae Island, respectively. Cold water masses appear at estuarine area when the discharge of Sumjin river is affluent. Amplitude of temperature fluctuation whose period is less than semi-diurnal is largest at Hadong coast and around Dae Island. Spectral analysis of surface water temperature shows a significant peak at a periodic fluctuation of 0.5 to 24 days and about 15-day period of predominant fluctuation is most frequent in Yeosu Bay. From the cross-correlation analysis of temperature fluctuations, Yeosu Bay can be classified into six areas; the south area affected by South Sea of Korea, the mixed area in the center of the bay, the estuarine area affected by river discharge at the north of the bay, the hot waste water area near Hadong coast, the area around Dae Island and the area near Noryang Channel affected by the water in Jinju Bay, respectively.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1260-1264
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• 2009

Precipitation time series is a mixture of complicate fluctuation and changes. The monthly precipitation data of 61 stations during 36 years (1973-2008) in Korea are comprehensively analyzed using the EOFs technique and CSEOFs technique respectively. The main motivation for employing this technique in the present study is to investigate the physical processes associated with the evolution of the precipitation from observation data. The twenty-five leading EOF modes account for 98.05% of the total monthly variance, and the first two modes account for 83.68% of total variation. The first mode exhibits traditional spatial pattern with annual cycle of corresponding PC time series and second mode shows strong North South gradient. In CSEOF analysis, the twenty-five leading CSEOF modes account for 98.58% of the total monthly variance, and the first two modes account for 78.69% of total variation, these first two patterns' spatial distribution show monthly spatial variation. The corresponding mode's PC time series reveals the annual cycle on a monthly time scale and long-term fluctuation and first mode's PC time series shows increasing linear trend which represents that spatial and temporal variability of first mode pattern has strengthened. Compared with the EOFs analysis, the CSEOFs analysis preferably exhibits the spatial distribution and temporal evolution characteristics and variability of Korean historical precipitation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권1호
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• pp.114-130
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• 2021

With the drastic growth of Information and Communication Technology (ICT) industry, global energy consumption is exponentially increased by mobile communications. The huge energy consumption and increased environmental awareness have triggered great interests on the research of dynamic distribution of cell user and traffic, and then designing the energy efficient cellular network. In this paper, we explore the temporal and spatial characteristics of human mobility and traffic distribution using real data set. The analysis results of cell traffic illustrate the tidal effect in temporal and spatial dimensions and obvious periodic characteristics which can be used to design Base Station (BS) dynamic with sleeping or shut-down strategy. At the same time, we designed a new Cell Zooming and BS cooperation mode. Through simulation experiments, we found that running in this mode can save about 35% of energy consumption and guarantee the required quality of service.

• 한국지역지리학회지
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• 제18권4호
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• pp.414-432
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• 2012

지가는 도시의 구조와 변화를 읽어 낼 수 있는 공간 텍스트이다. 본 연구의 목적은 대구시를 대상으로 상세한 공간 및 시간 해상도를 갖는 지가의 시공간적 변화를 탐색적으로 분석하여 공간구조 특성과 변동을 파악하는 것이다. 이를 위하여 1995년부터 2011년까지 2년 단위 표준지 공시지가를 이용하여 지가면(land value surface)을 생성하였다. 시기별 지가분포 및 변동률 패턴을 비교하여 지구적 혹은 국가적 수준의 경기변동 및 정책변화, 국지적 수준의 지역개발과 관련된 의사결정이 도시공간구조 변화에 어떻게 투영되었는지 파악하였다. 또한 음지수모형을 이용하여 도심으로부터의 거리 변수가 지가 분포의 공간적 변이를 얼마나 설명하는지를 분석하여 교외화 추세와 도시구조의 다핵화 경향을 파악하였다. 상이한 수준의 공간 의사결정을 반영하는 지가를 이용한 도시 분석은 도시 내부구조 변화에 대한 보다 상세한 이해를 제공할 뿐만 아니라 도시 및 지역개발 정책을 수립하고 그 영향을 평가하는데 유용한 정보를 제공할 것으로 기대한다.

• 해양환경안전학회지
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• 제21권4호
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• pp.315-326
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• 2015

진주만해역 수온의 시공간적 변동특성을 장기 연속수온관측 자료를 이용하여 분석하였다. 수온은 1월 말 최저, 8월 초 최대이고 만 북쪽이 중앙과 남쪽보다 계절변동이 작다. 하계 최고수온의 최저와 최고는 지족수로 주변에 출현한다. 노량수로와 대방수로는 조류 유 출입에 따른 수층 간 연직혼합으로 수온변동이 작다. 외해수 영향이 작은 만 남쪽은 동계 해면냉각과 하계 가열에 의한 변동이 현저하다. 바람은 대방수로 주변이 강해 조류와 함께 이 해역 표층의 혼합정도에 큰 영향을 준다. 만내수온이 균일하게 낮고 소조기 서풍이 강해져 노량수로에 동쪽방향 항류가 출현할 때 만 북쪽 해역에 난수가 유입되는 양상을 보여준다. 노량수로 해역은 7~20일의 장주기, 창선도 서쪽과 지족수로는 장주기와 반일주기, 만 중앙은 장주기와 일일주기 수온변동이 우세하다. Coherence 분석결과, 노량수로의 수온변동은 만 내 정점과 상관성이 크고 위상이 앞서나 대방수로보다는 느리다. 대방수로의 수온변동은 만 서쪽과 중앙 일부에 영향을 준다. 상호상관계수분석으로 진주만은 노량수로역, 만 북쪽 수렴발산역, 대방수로역, 창선도연안수역, 만 중앙혼합수역, 만 중앙내 만수역으로 분류되었다.

• 한국농림기상학회지
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• 제4권3호
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• pp.175-196
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• 2002

The increase of meteorological uncertainty and unstable fluctuation of its behavior due to the global warming affect the temporal variation and spatial distribution of water resources and water use patterns in agriculture. There have been steady efforts to understand hydrological components and deal with such water related problems. This paper reviews firstly, the future effect of water resources due to climate changes, secondly, recent progress for precipitation, evapotranspiration, soil moisture, and thirdly, GIS/RS based integrated information systems conducted by both researchers and government ministries. There should be continuous studies and investments to cope with climate changes, and to accomplish sustainable development with the help of agricultural water resources. Some research topics were suggested to attempt with substantial contents considering our present capability and situation.

• Journal of electromagnetic engineering and science
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• 제1권1호
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• pp.18-23
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• 2001

A fast-sweep broadband FM reflectometer system has been successfully developed and operacted at the DIII-D tokamak, producing reliable density Profiles with excellent spatial (1 $\leq$ cm) and temporal resolution (~100 $\mu$ s). The system uses a solid-state microwave oscillator and an active quadrupler, covering full Q-band frequencies (33~50 GHz) and providing relatively high output power (20~60 mW). The system hardware allows fu11band frequency sweep in 10 $\mu$ s, but due to digitization rate limit on DIII-D, sweep time was limited to 75~100 $\mu$ s. Fast frequency sweep has helped to reduce density fluctuation effects on the reflectometer phase measurements, thus improving reliability for individual sweeps. The fast-sweep system with high spatial and temporal resolution has allowed to measure fast-changing edge density profiles during plasma ELMS and L-H transitions, thus enabling fast-time sca1e physics studies.

• 비파괴검사학회지
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• 제32권3호
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• pp.263-268
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• 2012

It is important to know the mechanism of cell membrane fluctuation because it can be readout for the nanomechanical interaction between cytoskeleton and plasma membrane. Traditional techniques, however, have drawbacks such as probe contact with the cell surface, complicate analysis, and limit spatial and temporal resolution. In this study, we developed a new system for non-contact measurement of nano-scale localized-cell surface dynamics using modified-scanning ion-conductance microscopy. With 2 nm resolution, we determined that endothelial cells have local membrane fluctuations of ~20 nm, actin depolymerization causes increase in fluctuation amplitude, and ATP depletion abolishes all membrane fluctuations.

• Journal of Construction Engineering and Project Management
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• 제2권4호
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• pp.32-41
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• 2012

In recent times, multi-centralization and decentralization as well as large Capital area and suburbanization in the spatial structure of capital area. With rapid growth, urbanization and industrialization are unsystematic, and growth inequality between regions caused negative effects such as discordant centralization and decentralization, fluctuating land value, and gap between living conditions. Accordingly, this study analyzed urban spatial indexes by the self-governed body in the capital area such as Seoul, Incheon, and Gyeonggi province for the analysis of the regional inequality phenomenon. We examined the characteristics of temporal and spatial changes in urban spatial structure in the capital area by utilizing the distribution pattern and density of city indexes such as population, employment, etc, and then drew the commonality of those factors through factor analysis. We evaluated the drawn results through the city standard index by each city, conducted factor score analysis, and identified the interaction between each factor and Housing Purchase Price Composite Indices index, housing rent price index(Housing Jeonse Price Composite Indices), land price fluctuation rate, diffusion ratio of house, and financial independence.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.63-66
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• 2003

This study applied a hydrogeological field survey and isotope investigation to identify source locations and delineate pathways of groundwater contamination by nitrogen compounds. The infiltration and recharge processes were analyzed with groundwater-level fluctuation data and oxygen-hydrogen stable isotope data. The groundwater flow pattern was investigated through groundwater flow modeling and spatial and temporal variation of oxygen isotope data. Based on the flow analysis and nitrogen isotope data, source types of nitrate contamination in groundwater are identified. Groundwater recharge largely occurs in spring and summer due to precipitation or irrigation water in rice fields. Based on oxygen isotope data and cross-correlation between precipitation and groundwater level changes, groundwater recharge was found to be mainly caused by irrigation in spring and by precipitation at other times. The groundwater flow velocity calculated by a time series of spatial correlations, 231 m/yr, is in good accordance with the linear velocity estimated from hydrogeologic data. Nitrate contamination sources are natural and fertilized soils as non-point sources, and septic and animal wastes as point sources. Seasonal loading and spatial distribution of nitrate sources are estimated by using oxygen and nitrogen isotopic data.