Comparison of Methods for Characterizing Sound Absorbing Materials
Bibliographic record
Abstract
Open-cell porous materials are widely used as acoustic absorbent media in the transport industry.In order to have a prior knowledge o f their acoustic behaviour, different models have been developed [1][2][3][4].Among all these models, the Johnson-Champoux-Allard [2,4] is widely used because o f it simplicity and accuracy.This model uses five parameters (open porosity, static airflow resistivity, tortuosity, viscous characteristic length and thermal characteristic length) which describe the internal structure of porous materials at the macroscopic scale.Different methods have been developed in order to characterize those parameters.Some of them are based on the physical and mathematical definition o f the parameters.However, these methods, qualified as direct methods, require dedicated equipments.The second approach is based on the acoustical model from which analytical expressions linking the material parameters to acoustical measurements are derived.The methods using this approach are qualified as analytical inversion or indirect methods.Finally, the last approach is based on an optimisation problem where the material parameters are adjusted in the acoustic model to reproduce acoustical measurements.The methods o f this group are qualified as inverse methods.
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How this classification was reachedexpand
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 | 0.000 | 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)
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 teacher head, 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".