• 한국해양환경ㆍ에너지학회지
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• 제15권4호
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• pp.314-322
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• 2012

섬진강 하구에서 수온, 염분, pH, 용존산소, 부유입자물질, 영양염류, 엽록소 a의 시간에 따른 변화 양상을 파악하기 위해서 2006년 3월(건기)과 7월(우기)에 각각 25시간 연속관측을 실시하였다. 또한 공간적인 분포특성을 파악하기 위해서 염분경사에 따라 해양환경 조사를 실시하였다. 섬진강 하구에서 염분의 변화는 건기에는 조석주기, 우기에는 강물 유출량에 영향을 받는 것으로 나타났다. 용존무기영양염류(질산염, 아질산염, 규산염) 농도의 시공간적 분포는 건기에는 염분의 변화와 좋은 상관관계를 보였다. 반면 우기에는 시간에 따라 농도 변화가 작았다. 우기시 영양염류의 평균 농도는 건기에 비해 용존무기질산염의 경우 약 6배, 용존무기인의 경우 약 4배, 용존무기규산염의 경우 약 43배 높게 나타났다. 엽록소 a 농도는 용존무기영양염류의 농도가 높은 우기에 비해 건기에 높게 나타났다. 이 연구결과, 우기와 건기에 해양환경인자의 시공간적 분포는 조석과 강물유출량의 영향에 의해 결정되며, 엽록소 a의 분포는 용존무기영양염류의 분포보다는 담수의 유출량 변화와 연관성이 있는 것으로 판단된다.

• 한국환경과학회지
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• 제21권4호
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• pp.535-543
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• 2012

The aerosol number concentration have measured with an aerodynamic particle sizer spectrometer(APS) at Gosan site, which is known as background area in Korea, from January to September 2011. The temporal variation and the size distribution of aerosol number concentration have been investigated. The entire averaged aerosol number concentration in the size range 0.25~32.0 ${\mu}m$ is about 252 particles/$cm^3$. The number concentration in small size ranges(${\leq}0.5{\mu}m$) are very higher than those in large size ranges, such as, the number concentration in range of larger than 6.5 ${\mu}m$ are almost zero particles/$cm^3$. The contributions of the number concentration to PM10 and/or PM2.5 are about 34%, 20.1% and 20.4% in the size range 0.25~0.28 ${\mu}m$, 0.28~0.30 ${\mu}m$ and 0.30~0.35 ${\mu}m$, respectively, however, the contributions are below 1% in range of larger than 0.58 ${\mu}m$. The monthly variations in the number concentration in smaller size range(<1.0 ${\mu}m$) are evidently different from the variations in range of larger than 1.0 ${\mu}m$, but the variations are appeared similar patterns in smaller size range(<1.0 ${\mu}m$), also the variations in range of larger than 1.0 ${\mu}m$ are similar too. The diurnal variations in the number concentration for smaller particle(<1.0 ${\mu}m$) are not much, but the variations for larger particle are very evident. Size-fractioned aerosol number concentrations are dramatically decreased with increased particle size. The monthly differences in the size-fractioned number concentrations for smaller size range(<0.7 ${\mu}m$) are not observed, however, the remarkable monthly differences are observed for larger size than 0.7 ${\mu}m$.

• 한국물환경학회지
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• 제25권3호
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• pp.394-403
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• 2009

A total of 52 sampling sites were selected in the stream network of the upper Paldang watershed (e.g. Kyonan, Gapyeong, Jojong, Chengmi, Bockha, Yanghwa and Heuk streams). Over the time period of April 2007-February 2008, 1820 samples were collected and analyzed for physico-chemical variables of the upper watershed in order to investigate spatio-temporal water quality variation in particular the relationship with land use. Although temporal variations of water quality in each stream were similar and were significantly influenced by flow, spatial variations in each stream varied as physico-chemical characteristics of upper watershed. As a result of regression analysis, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Nitrogen (T-N), and Total phosphorus (T-P) concentration were the most significantly and positively associated with people population density. It is necessary to manage not only water quality but also land use of upper watershed and flow flux.

• 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.

• International Journal of Contents
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• 제7권4호
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• pp.19-23
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• 2011

This paper proposes a segmentation method for overlapped vehicles based on analysis of the vehicle location and the spatiotemporal association information. This method can be used in an intelligent transport system. In the proposed method, occlusion is detected by analyzing the association information based on a vehicle's location in continuous images, and occlusion segmentation is carried out by using the vehicle information prior to occlusion. In addition, the size variations of the vehicle to which association tracking is applied can be anticipated by learning the variations according to the overlapped vehicles' movements. To assess the performance of the suggested method, image data collected from CCTVs recording traffic information is used, and average success rate of occlusion segmentation is 96.9%.

• 대기
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• 제20권1호
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• pp.1-12
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• 2010

Temporal distributions and characteristics of PWV (Precipitable Water Vapor) and LWP (Liquid Water Path) are investigated by using the microwave radiometric profiler at Haenam NCIO from 1 August 2007 to 31 July 2008. Temporal variations of PWV are closely connected with the thermal response of water vapor in atmosphere. The variations of LWP are characterized by the rainfall variation being basically attributable to the heavy rain-bearing clouds. The frequency distributions of PWV and LWP according to the four sky conditions ('clear', 'lightly cloudy', 'cloudy', and 'deeply cloudy') by total cloud amount at Wando Observatory corresponds with a change of slope in cumulative distribution function for PWV and LWP. There results implies that the classification of sky condition can be applied by using the distribution of PWV and LWP from microwave radiometric profiler.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권7호
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• pp.489-494
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• 2009

멀티미디어 콘텐트는 다양한 대역폭, 해상도, 압축형식으로 독립적으로 인코딩되므로, 동일한 비디오 부분이 다양한 형식의 변형 파일 안에서 다른 시간적 위치에 저장될 수 있다. 이 논문에서는 멀티미디어 콘텐트를 재생 중이거나 혹은 재생 전에, 콘텐트 시청의 끊김이나 중복 없이 임의의 다양한 형식의 변형 파일들 사이에 같은 비디오 부분을 정확히 접근 할 수 있는 견고한 멀티미디어 북마크 메커니즘을 제안한다. 또한 직관적이고 시각적인 인터페이스를 통하여 사용자가 북마크를 관리할 수 있는 새로운 멀티미디어 북마크 재생기를 제안한다.

• 천문학논총
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• 제15권spc2호
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• pp.1-13
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• 2000

Through the coupling between the near-earth space environment and the polar ionosphere via geomagnetic field lines, the variations occurred in the magnetosphere are transferred to the polar region. According to recent studies, however, the polar ionosphere reacts not only passively to such variations, but also plays active roles in modifying the near-earth space environment. So the study of the polar ionosphere in terms of geomagnetic disturbance becomes one of the major elements in space weather research. Although it is an indirect method, ground magnetic disturbance data can be used in estimating the ionospheric current distribution. By employing a realistic ionospheric conductivity model, it is further possible to obtain the distributions of electric potential, field-aligned current, Joule heating rate and energy injection rate associated with precipitating auroral particles and their energy spectra in a global scale with a high time resolution. Considering that the ground magnetic disturbances are recorded simultaneously over the entire polar region wherever magnetic station is located, we are able to separate temporal disturbances from spatial ones. On the other hand, satellite measurements are indispensible in the space weather research, since they provide us with in situ measurements. Unfortunately it is not easy to separate temporal variations from spatial ones specifically measured by a single satellite. To demonstrate the usefulness of ground magnetic disturbance data in space weather research, various ionospheric quantities are calculated through the KRM method, one of the magneto gram inversion methods. In particular, we attempt to show how these quantities depend on the ionospheric conductivity model employed.

• 대한기계학회논문집B
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• 제22권5호
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• pp.651-660
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• 1998

In the LPCVD reactor the temperature variations within the wafer load are the most important factor to maintain the thickness of the materials deposited on the surface of the wafer constant and to affect the deformation of each wafer. In this study the temporal variations of radial and axial temperature nonuniformities of each wafer in the LPCVD reactor are numerically estimated by assuming diffuse reflection. To verify the validity of the present numerical results, the present results obtained from the transient analysis are compared with those of Badgwell's work in which a steady-state condition was assumed. The main objective of this work is to determine the temporal variations of the temperature of each wafer in the LPCVD process since the wafers experience severe change in temperature in the early stage of the process.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.463-466
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• 2009

The numerical simulation optimized by Four Dimensional Data Assimilation (FDDA) with Quick Scatterometer (QuikSCAT) data is carried out to evaluate wind resource characteristics at various heights in the southeastern area of the Korean Peninsula, where wind farms are planned to be built on on- and off-shore as well as comparable diurnal wind variations are characterized at the surface. The temporal and spatial distributions of modeled wind speeds showed good agreement with the observations based on the temporal variation analysis. Model results indicate that the higher model is performed in resolution, the more precise results is at turbine hub height. Occasionally, wind speed variations for each numerical resolution has a different regional and seasonal variations. In the coast area, hub height wind speed of 9km-resolution is simillar to that of 3km-resolution. On the other hand, hub height wind speed of 3km-resolution is simillar to that of 1km-resolution in the Jiri mountainous area.