Automatic field data analyzer for closed-loop vehicle design

2014 ◽  
Vol 259 ◽  
pp. 321-334 ◽  
Author(s):  
Yilu Zhang ◽  
Xinyu Du
Geophysics ◽  
2018 ◽  
Vol 83 (4) ◽  
pp. R297-R305 ◽  
Author(s):  
Mikhail Davydenko ◽  
D. J. Verschuur

Nowadays, it is more widely accepted that multiple reflections should not be considered as noise, but as signal that can provide additional illumination of the subsurface. However, one of the challenges in seismic imaging is including all multiples in the migration process for field data in a reliable manner. Although including surface multiples in imaging has been demonstrated already on field data in recent years, the proper imaging of internal multiples is less established. We have determined successful field data applications on imaging that takes all internal multiples into account. This is done via so-called full-wavefield migration (FWM), an inversion-based method in which, given the migration velocity model, the angle-dependent reflectivity is iteratively estimated by minimizing the misfit between the modeled and the measured data. Its forward model is based on a multidimensional version of the so-called Bremmer series, which allows modeling of transmission effects and any type of multiple scattering in the subsurface and, thereby, is able to minimize the data misfit correctly. An application of FWM on deepwater field data from the Norwegian North Sea validates its capabilities to explain and image internal multiples. Furthermore, it is demonstrated on the same field data that the FWM framework can also be used for data interpolation and primary/multiple separation.


Geophysics ◽  
2021 ◽  
pp. 1-32
Author(s):  
Shan Qu ◽  
Eric Verschuur ◽  
Dong Zhang ◽  
Yangkang Chen

Accurate removal of surface-related multiples remains a challenge in shallow-water cases. One reason is that the success of the surface-related multiple estimation (SRME) related algorithms is sensitive to the quality of the near-offset reconstruction. When it comes to a larger missing gap and a shallower water-bottom, the state-of-the-art near-offset gap construction method — parabolic Radon transform (PRT) — fails to provide a reliable recovery of the shallow reflections due to the limited information from the data and highly curved events at near offsets with strong lateral amplitude variations. Therefore, we propose a novel workflow, which first deploys a deep-learning(DL)-based reconstruction of the shallow reflections and then uses the reconstructed data as the input for the subsequent surface multiple removal. In particular, we use a convolutional neural network architecture --- U-net, which was developed from convolutional autoencoders with extra direct skip connections between different levels of encoders and the corresponding decoders. Instead of using field data directly in network training, the training set is carefully synthesized based on the prior water-layer information of the field data; thus, a fully sampled field dataset, which is hard to obtain, is not needed for training in the proposed workflow. An inversion-based approach — closed-loop surface-related multiple estimation (CL-SRME) -- is used for the surface multiple removal, in which the primaries are directly estimated via full waveform inversion in a data-driven manner. Finally, the effectiveness of the proposed workflow is demonstrated based on a 2D North Sea field data in a shallow-water scenario (92.5 m water depth) with a relatively large minimum offset (150 m).


1961 ◽  
Vol 41 (3) ◽  
pp. 245-250 ◽  
Author(s):  
George H. Bornside ◽  
Isidore Cohn
Keyword(s):  

2012 ◽  
Vol 220 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Sandra Sülzenbrück

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.


2003 ◽  
Vol 14 (5) ◽  
pp. 471-477
Author(s):  
Dejan M. Novakovic ◽  
Markku J. Juntti ◽  
Miroslav L. Dukic

Sign in / Sign up

Export Citation Format

Share Document