Bibliographic record
Abstract
Previous works have shown that it is possible to create a pulsed beam of acoustic energy which maintains amplitude and beam width better than either conventional single frequency or wide-band beams of comparable frequency content. The reconstruction technique to date uses Helmholtz' approximation on a planar array composed of individually addressable elements. In this work, a new array geometry is studied. Simulated focused scalar fields representing approximations to the Focus Wave Modes (FWM) are generated from a finite cylindrical aperture. The driving functions are derived using Huygens' representation for an infinite cylindrical surface. Performance of this new launching scheme is compared to the planar array launch of FWMs and Gaussian pulses. Through the course of simulations, we illustrate how the array spacing or discretization and the surface truncation affect the reconstruction quality and performance. The influence of array size and shape defined by the ratio of length over radius on the spreading and attenuation of the radiated beam is studied. The beam width, amplitude and sidelobe intensity are compared to those obtained from a planar array. It is shown that the cylinder length can be truncated to a certain value, Z[sub pc1], without affecting the pulse reconstruction at the origin. A shorter array can also be used with some loss in reconstruction quality. The generated localized wave from the cylindrical aperture is also compared to the Gaussian pulse. It is shown that a sufficient cylinder length will generate a field with better quality close to the array and similar performance and quality for further distances than that synthesized by a planar array of the same radius. Finally we use an approximation of the source functions to solve the problem caused by space-time inseparability of localized waves. We show that it is possible to find a simple relation between the various functions that drive the array elements. Without affecting significantly the radiated field, this method reduces dramatically the number of independent generators that are necessary to launch the pulse. The pulse can be generated from a cylindrical aperture using a single generator—while for a planar array of the same radius, more than 4000 independent generators would be required to obtain a similar beam quality.
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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 | 0.000 | 0.001 |
| 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) | 0.001 | 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".