Three-dimensional ionospheric tomography reconstruction using the model function approach in Tikhonov regularization

2016 ◽  
Vol 121 (12) ◽  
pp. 12,104-12,115 ◽  
Author(s):  
Sicheng Wang ◽  
Sixun Huang ◽  
Jie Xiang ◽  
Hanxian Fang ◽  
Jian Feng ◽  
...  



Radio Science ◽  
1998 ◽  
Vol 33 (6) ◽  
pp. 1793-1805 ◽  
Author(s):  
Chaitali Biswas ◽  
Helen Na


2018 ◽  
Vol 10 (1) ◽  
pp. 196-201 ◽  
Author(s):  
Julien Le Moal ◽  
Christophe Peillon ◽  
Jean-Nicolas Dacher ◽  
Jean-Marc Baste


2018 ◽  
Vol 11 (12) ◽  
pp. 4873-4888 ◽  
Author(s):  
Christopher J. Skinner ◽  
Tom J. Coulthard ◽  
Wolfgang Schwanghart ◽  
Marco J. Van De Wiel ◽  
Greg Hancock

Abstract. The evaluation and verification of landscape evolution models (LEMs) has long been limited by a lack of suitable observational data and statistical measures which can fully capture the complexity of landscape changes. This lack of data limits the use of objective function based evaluation prolific in other modelling fields, and restricts the application of sensitivity analyses in the models and the consequent assessment of model uncertainties. To overcome this deficiency, a novel model function approach has been developed, with each model function representing an aspect of model behaviour, which allows for the application of sensitivity analyses. The model function approach is used to assess the relative sensitivity of the CAESAR-Lisflood LEM to a set of model parameters by applying the Morris method sensitivity analysis for two contrasting catchments. The test revealed that the model was most sensitive to the choice of the sediment transport formula for both catchments, and that each parameter influenced model behaviours differently, with model functions relating to internal geomorphic changes responding in a different way to those relating to the sediment yields from the catchment outlet. The model functions proved useful for providing a way of evaluating the sensitivity of LEMs in the absence of data and methods for an objective function approach.



2019 ◽  
Vol 112 (2) ◽  
pp. 137-140
Author(s):  
Martin J. C. Gemert ◽  
Geert J. Streekstra ◽  
Frank P. H. A. Vandenbussche ◽  
Peter G. J. Nikkels ◽  
Jeroen P. H. M. Wijngaard


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Norio Baba ◽  
Kenji Kaneko ◽  
Misuzu Baba

AbstractWe report a new computed tomography reconstruction method, named quantisation units reconstruction technique (QURT), applicable to electron and other fields of tomography. Conventional electron tomography methods such as filtered back projection, weighted back projection, simultaneous iterative reconstructed technique, etc. suffer from the ‘missing wedge’ problem due to the limited tilt-angle range. QURT demonstrates improvements to solve this problem by recovering a structural image blurred due to the missing wedge and substantially reconstructs the structure even if the number of projection images is small. QURT reconstructs a cross-section image by arranging grey-level quantisation units (QU pieces) in three-dimensional image space via unique discrete processing. Its viability is confirmed by model simulations and experimental results. An important difference from recently developed methods such as discrete algebraic reconstruction technique (DART), total variation regularisation—DART, and compressed sensing is that prior knowledge of the conditions regarding the specimen or the expected cross-section image is not necessary.



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