• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.259-261
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• 2008

GIS-based spatial data integration tasks have used exhaustive thematic maps generated from sparsely sampled data or satellite-based exhaustive data. Due to a simplification of reality and error in mapping procedures, such spatial data are usually imperfect and of different accuracy. The objective of this study is to carry out a sensitivity analysis in connection with input topographic data for landslide hazard mapping. Two different types of elevation estimates, elevation spot heights and a DEM from ASTER stereo images are considered. The geostatistical framework of kriging is applied for generating more reliable elevation estimates from both sparse elevation spot heights and exhaustive ASTER-based elevation values. The effects of different accuracy arising from different terrain-related maps on the prediction performance of landslide hazard are illustrated from a case study of Boeun, Korea.

• Journal of the Korean Statistical Society
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• 제36권1호
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• pp.57-76
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• 2007

Kriging is a nonparametric regression method used in geostatistics for estimating curves and surfaces for spatial data. It may come as a surprise that the Kriging estimator, normally derived as the best linear unbiased estimator, is also the solution of a particular variational problem. Thus, Kriging estimators can also be interpreted as generalized smoothing splines where the roughness penalty is determined by the covariance function of a spatial process. We build off the early work by Silverman (1982, 1984) and the analysis by Cox (1983, 1984), Messer (1991), Messer and Goldstein (1993) and others and develop an equivalent kernel interpretation of geostatistical estimators. Given this connection we show how a given covariance function influences the bias and variance of the Kriging estimate as well as the mean squared prediction error. Some specific asymptotic results are given in one dimension for Matern covariances that have as their limit cubic smoothing splines.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.262-265
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• 2000

In order to estimate spatial physicochemical properties of the spring waters in the study area, spring waters at 57 sites were investigated for measuring ten items (temperature, pH, Eh, EC, TDS, DO, salinity, alkalinity, discharge rate, and surface elevation), To compare each component with one another, regression analysis was carried out. Kriging was used to estimate the spatial characteristics and continuity of data in the study area. To solve kriging equation, the semivariogram was calculated using geostatistical software GS$^{+}$(version 3.1). As a result of semivariogram analysis, the data of nine components but surface elevation could be assumed as stationary random function, and ordinary kriging method was used for making contour maps.s.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.302-302
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• 2006

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.555-555
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• 2009

A web GIS based database system of thermophysical property of rocks in Korea is under construction. Rock samples were randomly collected over the whole country and sample spacings were generally 1 to 10 km. Thermal diffusivity, spedific heat, thermal conductivity, specific heat, density and porosity were measured on a collection of 1,560 rock samples in the laboratory. The sampled rocks were classified into igneous, metamorphic and sedimentary rock types and the variables were statistically studied. The thermal conductivity were compared with thermal diffusivity, porosity and dry density to define any correlations and the distribution of thermal conductivity is characterized by the geostatistical analysis. The optimal mapping of thermal conductivity is very useful as a practical design component for any geothermal systems.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.229-232
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• 2003

본 연구는 울산지역 지하수오염 저감기술의 개발에 필요한 대수층의 공간적 분포특성을 파악하는 데 목적이 있다. 울산 공업도시의 대수층에서 공간적 분포특성을 파악하기 위하여 시추조사가 많이 필요 하지만 비용 및 시간 관계상 어려움이 있기 때문에, 지질조사 보고서나 논문 등에서 지하수자료와 시추 자료를 획득하여 지구통계기법을 이용한 울산지역 대수층의 공간적 분포를 모사하였다. 그리고 인구가 밀집되어 있는 남구와 중구를 중심으로 대수층 단면 분포를 모사하였다. 이와 같은 분석결과는 표토층 하부경계부와 풍화대 하부경계부에서 유사한 분포심도로 나타났으며, 지하수 수위는 표토층 하부경계와 암반층 상부경계부인 풍화대에 분포하는 것으로 나타났다.

• 자원환경지질
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• 제32권1호
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• pp.63-72
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• 1999

In order to examine the contamination levels of trace elements in stream sediments in the Chungnam coal mine area, stream sediment and water samples were collected and analyzed for trace elements. The pH of stream water was neutral or weak-alkaline and the mobility of metal in stream sediments was supposed to be low. From the result of cluster analysis, non-polluted sampling stations can be distinguished from polluted sampling stations influenced by mining activities. The trace element concentrations in sediments from non-polluted zone were considered to be the natural backround concentrations of this area. The trace element concentrations in sediment samples from the mining area were higher than those from non-polluted area, and contaminated area of enriched trace element levels need to be properly managed. From the results of discriminant and regression analyses, concentrations of Cd, Cu, Pb AND zN and predicted values of Be, Mo, and Ni in Chungnam coal mine area were found to be lower than those in metal mining areas in Korea.

• Journal of the Korean Data and Information Science Society
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• 제26권2호
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• pp.495-504
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• 2015

The Gaussian geostatistical model has been widely used for modeling spatial data. However, this model suffers from a severe difficulty in computation because inference requires to invert a large covariance matrix in evaluating log-likelihood. In addressing this computational challenge, three strategies have been employed: likelihood approximation, lower dimensional space approximation, and Markov random field approximation. In this paper, we reviewed statistical approaches attacking the computational challenge. As an illustration, we also applied integrated nested Laplace approximation (INLA) technology, one of Markov approximation approach, to real data to provide an example of its use in practice dealing with large spatial data.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.48-53
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• 2007

A new way to integrate various geophysical information for evaluation of RQD was developed. In this study, we did not directly define the RQD value where borehole data are not sampled. Instead, we infer the probability of RQD values with prior probability from borehole direct data, and secondary supporting probability from resistivity and seismic tomography data. For the integration, we applied the geostatstical indicator kriging to get prior probability of RQD value, and indicator kriging with soft data to get the supporting probability from resistivity and seismic data. And we finally use the permanence ratio rule to integrate these information. The finally obtained result was also analyzed to fully utilize the probabilistic features. We show the probability of wrongly classifying the RQD evaluation and vice versa. This result may be used for decision making process based on the geophysical exploration.

• 한국농공학회논문집
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• 제49권1호
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• pp.3-13
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• 2007

In this study, spatial characteristics of rainfall in Imha basin were investigated by cross-correlation analysis among rainfall gaging stations and rainfall-runoff analysis used in HEC-HMS model for analysis of influence on observed rainfall. The Kriging technique was applied to rain(all analysis in Imha basin to reflect spatial characteristics of regional rainfall. Their results are compared to rainfall-runoff data with spatially distributed rainfall data as well as the classical thiessen method. The results by kriging technique approached by geostatistical method could reflect spatial characteristics of regional rainfall properly in Imha basin.