Fresnel zones and the power of stacking used in the preparation of data for AVO analysis John C. Bancroft, and Shuang Sun, CREWES/University of Calgary Summary
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Bibliographic record
Abstract
The concept of a generalized prestack Fresnel zone is presented to aid in defining a prestack migration aperture for AVO analysis. A large migration aperture requires prestack amplitude scaling that may introduce anomalous results in areas where the acquisition geometry varies. Limiting the prestack migration aperture to the area of specula reflection energy allows the data to be summed into a prestack migration gather and then divided by the fold to balance the amplitudes. The size of the offset Fresnel zone is based on the zero-offset case and represents that portion of the migration operator that sums across a half wavelength of the reflector. In the offset case, that diffraction shape is defined by the double-square-root equation. In the prestack volume (x, h, t) the Fresnel zone can be illustrated by the intersection between the hyperbolic plane of the reflection energy, and the surface defined by the double-square-root equation. Examples show the results of limited aperture gathering on modelled and real data for horizontal events.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
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Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
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