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RISS 인기검색어
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- 저자 : Yaoguo Li (검색결과 4 건)
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최적 4진트리 격자화를 이용한 중력 및 중력 변화율 탐사에서의 고속 지형보정
( Kristofer Davis ),( M. Andy Kass ),( Yaoguo Li ) 한국지구물리·물리탐사학회 2011 지구물리와 물리탐사 Vol.14 No.1
최적화된 4진트리 격자화 기법을 이용한 중력변화율 탐사의 지형 효과 계산 방법을 제시하고자 한다. 제시하고자 하는 방법은 항공탐사의 자료처리를 위하여 지형 자료에 최적화된 빠르고 정확한 지형효과 계산법이다. 각 지점에서의 지형효과 계산에 이용되는 지표 고도 자료는 자동적으로 원하는 정밀도를 제공할 수 있는 최대 크기로 격자화 되어 최대 해상도 자료를 이용하는 방법에 비하여 빠른 계산이 가능하다. 이러한 최적화된 격자 크기는 각 지점에서의 거리와 지표의 고도 변화를 고려하여 구성된다. 새로운 접근 방법을 검증하기 위하여 수치모델링과 현장자료에 적용하였다. 현장 자료에 적용한 결과 최적 4진트리 기법은 최고 해상도 자료를 모두 이용한 방법과 비교하여 중력 변화율 자료에서 1EU(Eotvos unit)의 정밀도를 유지하면서 계산양은 1/351로 줄일 수 있었다. 또한, 중력탐사 결과의 지형보정에 이용한 결과 모든 DEM자료를 이용한 계산에 비하여 310배나 빠른 계산이 가능하였다. We present a method for modelling the terrain response of gravity gradiometry surveys utilising an adaptive quadtree mesh discretization. The data- and terrain-dependent method is tailored to provide rapid and accurate terrain corrections for draped and barometric airborne surveys. The surface used in the modelling of the terrain effect for each datum is discretized automatically to the largest cell size that will yield the desired accuracy, resulting in much faster modelling than full-resolution calculations. The largest cell sizes within the model occur in areas of minimal terrain variation and at large distances away from the datum location. We show synthetic and field examples for proof of concept. In the presented field example, the adaptive quadtree method reduces the computational cost by performing 351 times fewer calculations than the full model would require while retaining an accuracy of one Eotvos for the gradient data. The method is also used for the terrain correction of the gravity field and performed 310 times faster compared with a calculation of the full digital elevation model.
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Feasibility and Limitations of Void Detection Using Gravity Gradiometry
McKenna, Jason R.,Hyoungrea Rim,Yaoguo Li IEEE 2016 IEEE transactions on geoscience and remote sensing Vol.54 No.2
<P>Detecting and characterizing near-surface voids is a long-standing problem in near-surface geophysics primarily because of the low signal-to-noise ratio due to the typically small sizes of these targets. Anticipated advances in gravity gradiometry instrumentation and data acquisition may provide the improved resolution required to address these targets. In this paper, we investigate void detection using simulated full tensor gravity gradiometry data. We show through numerical simulations that low-altitude gravity gradiometry can observe signals from voids well above the modern instrument noise level. We develop a practical detection algorithm to determine the tunnel orientation and its location in the subsurface. The algorithm first finds the tunnel orientation through a tensor rotation and then solves for the tunnel location in the subsurface based on the directional vectors obtained from the rotated tensor data. We use this algorithm to study the feasibility and limitations of the gravity gradiometry technique in void detection. We conclude that the method can be effective in many practical scenarios.</P>
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Davis, Kristofer,Kass, M.Andy,Li, Yaoguo Korean Society of Earth and Exploration Geophysici 2011 지구물리와 물리탐사 Vol.14 No.1
We present a method for modelling the terrain response of gravity gradiometry surveys utilising an adaptive quadtree mesh discretization. The data- and terrain-dependent method is tailored to provide rapid and accurate terrain corrections for draped and barometric airborne surveys. The surface used in the modelling of the terrain effect for each datum is discretized automatically to the largest cell size that will yield the desired accuracy, resulting in much faster modelling than full-resolution calculations. The largest cell sizes within the model occur in areas of minimal terrain variation and at large distances away from the datum location. We show synthetic and field examples for proof of concept. In the presented field example, the adaptive quadtree method reduces the computational cost by performing 351 times fewer calculations than the full model would require while retaining an accuracy of one E$\"{o}$tv$\"{o}$s for the gradient data. The method is also used for the terrain correction of the gravity field and performed 310 times faster compared with a calculation of the full digital elevation model.
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