• 제목/요약/키워드: Spatial variation

검색결과 1,358건 처리시간 0.031초

Bayesian Spatial Modeling of Precipitation Data

  • Heo, Tae-Young;Park, Man-Sik
    • 응용통계연구
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    • 제22권2호
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    • pp.425-433
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    • 2009
  • Spatial models suitable for describing the evolving random fields in climate and environmental systems have been developed by many researchers. In general, rainfall in South Korea is highly variable in intensity and amount across space. This study characterizes the monthly and regional variation of rainfall fields using the spatial modeling. The main objective of this research is spatial prediction with the Bayesian hierarchical modeling (kriging) in order to further our understanding of water resources over space. We use the Bayesian approach in order to estimate the parameters and produce more reliable prediction. The Bayesian kriging also provides a promising solution for analyzing and predicting rainfall data.

시공간적 변동성을 고려한 지하수 함양량의 산정방안 (Estimation of Groundwater Recharge with Spatial-Temporal Variability)

  • 김남원;정일문;원유승
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2004년도 학술발표회
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    • pp.691-695
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    • 2004
  • In recent years, mary studies for efact estimation of groudwater recharge has been performed. They can be categorized into three groups : analytical method by means of groundwater recession curve, water budget analysis based on watershed, and the method using groundwater model. Since groundwater recharge rate shows the spatial-temporal variability due to hydrogeological heterogeneity, existing studies have various limits to deal with these characteristics. The method of estimating daily recharge rate with spatial-temporal variation based on rainfall-runoff model is suggested in this study for this purpose. This method is expected to enhance existing indirect method by means of reflecting climatic conditions, land use and hydrogeological heterogeneity.

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Spatial and Temporal Characteristics of LG StudioWorks 500LC (Flat Panel LCD)

  • Park, Seung-Ok;Kim, Hong-Suk;Lim, Yong-Jin;Yang, Jae-Youl
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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    • pp.165-166
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    • 2000
  • Spatial independence and temporal stability of flat-panel LCD monitor, LG StudioWorks 500LC, were evaluated. The luminance and chromaticity of stimulus color were measured according to the variation of the size, background color, and location on the screen. The spatial independence at center location is very good and not a limiting factor in its colorimetric characterization, however the spatial non-uniformity is a little severe. The warmup time to stabilize after initial power is about 100 minutes and short-term variance of white stimulus is within 0.1 ${\Delta}E^*\;_{ab}$.

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공간적 확률 과정 기반의 수율 정보를 이용한 번인과 신뢰성 검사 정책 (Differential Burn-in and Reliability Screening Policy Using Yield Information Based on Spatial Stochastic Processes)

  • 황정윤;심영학
    • 산업경영시스템학회지
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    • 제35권4호
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    • pp.1-9
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    • 2012
  • Decisions on reliability screening rules and burn-in policies are determined based on the estimated reliability. The variability in a semiconductor manufacturing process does not only causes quality problems but it also makes reliability estimation more complicated. This study investigates the nonuniformity characteristics of integrated circuit reliability according to defect density distribution within a wafer and between wafers then develops optimal burn-in policy based on the estimated reliability. New reliability estimation model based on yield information is developed using a spatial stochastic process. Spatial defect density variation is reflected in the reliability estimation, and the defect densities of each die location are considered as input variables of the burn-in optimization. Reliability screening and optimal burn-in policy subject to the burn-in cost minimization is examined, and numerical experiments are conducted.

마산만에 출현하는 난자치어 종조성과 출현량의 시공간 변동 (Temporal and Spatial Variation in Species Composition and Abundances of Ichthyoplankton in Masan Bay)

  • 곽석남;박주면
    • 한국어류학회지
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    • 제26권1호
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    • pp.42-49
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    • 2014
  • 조사기간 동안 총 4종의 부유성 어란과 24종의 자치어가 마산만에서 채집되었다. 어란의 우점종은 멸치 (Engraulis japonicus) 어란이었다. 그러나 자치어는 앞동갈베도라치 (Omobranchus elegan), 고등어 (Scomber japonicus), 문절망둑 (Acanthogobius flavimanus), 쥐노래미 (Hexagrammos otakii), 돛양태류 (Repomucenus sp.), Scartella cristata, 망둥어과(Gobiidae sp.) 순으로 우점하였다. 이들 7종은 전체 출현개체수의 78.5%를 차지하였다. 어란과 자치어는 시공간적으로 큰 변동을 보였다. 어란과 자치어의 현존량은 2007년 7월에 가장 높았으며, 2007년 2월에 가장 낮았다. 그리고 난자치어는 다른 정점에 비해 정점 5에서 현존량이 높았다. 어란과 자치어 현존량의 시간적 변화는 수온에 영향을 받았다. 부유성 어란과 자치어는 수심, 지형 등과 같은 물리적 환경 요인에 따라 좀 더 얕은 만 안쪽 정점과 깊은 만 외곽 정점 간 군집 차이를 보였다.

2007년 여름 북서태평양 이산화탄소 분압의 공간 변동성 (Spatial Variability of Surface fCO2 in the Western North Pacific during Summer 2007)

  • 최상화;김동선;김경희;민홍식
    • Ocean and Polar Research
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    • 제30권3호
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    • pp.335-345
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    • 2008
  • In order to study spatial variabilities and major controlling factors, we measured fugacity of $CO_2(fCO_2)$, temperature, salinity and nutrients in surface waters of the North Pacific($7^{\circ}30'{\sim}33^{\circ}15'N$, $123^{\circ}56'E{\sim}164^{\circ}24'W$) between September$\sim$October 2007. The North Pacific and the marginal sea were distinguished by $fCO_2$ distribution as well as unique characteristics of temperature and salinity. There was a distinct diurnal SST variation in the tropical North Pacific area, and surface $fCO_2$ coincidently showed diurnal variation. In the North Pacific area, surface $fCO_2$ was mainly controlled by temperature, while in the marginal sea area it was primarily dependent on alkalinity and dissolved inorganic carbon concentrations. Air-sea $CO_2$ flux showed a large spatial variation, with a range of $-6.10{\sim}5.06\;mmol\;m^{-2}day^{-1}$. The center of subtropical gyre of North Pacific acted as a source of $CO_2(3.09{\pm}0.95\;mmol\;m^{-2}day^{-1})$. Tropical western North Pacific (i.e. the 'warm pool' area and the subtropical western North Pacific) acted as weak sources of $CO_2$($1.07{\pm}1.20\;mmol\;m^{-2}day^{-1}$ and $0.50{\pm}0.53\;mmol\;m^{-2}day^{-1}$, respectively). In the marginal sea, however, the flux was estimated to be $-0.68{\pm}1.17\;mmol\;m^{-2}day^{-1}$, indicating that this area acted as a sink for $CO_2$.