Statistical analysis and modeling of active sonar echoes from a shipwreck
Bibliographic record
Abstract
A statistical analysis of active sonar echoes from a shipwreck at 36° 18.804′ north by 14° 41.136′ east (Malta Plateau region in the Mediterranean Sea) is performed as a function of azimuth at both 2 km and 10 km range for broadband transmit waveforms in low- and mid-frequency bands. The data were taken in May 2007 during the NATO Undersea Research Centre (NURC) Clutter 2007 sea trial. The data are compared with standard probability density function models and seen to be extremely heavy-tailed with respect to Rayleigh and even K envelope distributions. Models containing a coherent scattering component (e.g., Rician and generalized K) are seen to provide a better fit to the data. Statistical measures from the two different ranges and two different frequency bands are seen to be correlated as a function of azimuth indicating minimal changes in the statistics of the scattering. [This work was sponsored by the Office of Naval Research under contract number N0001407C0092 and made possible by the CLUTTER Joint Research Project (JRP), including as Participants the NURC, Pennsylvania State University-ARL-PSU (USA), Defence Research and Development Canada-DRDC-A (CAN), and the Naval Research Laboratory-NRL (USA).]
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".