Toward a realistic estimate of octave band sound levels for electric transformers
Bibliographic record
Abstract
The typical starting point, when evaluating the sound emissions of a proposed transformer, is to obtain the manufacturer's sound level data or develop an estimate using generic prediction equations from a published textbook.If sound level information is available from the transformer manufacturer -whether measured or estimated -it is usually given only in terms of an overall A-weighted ("dBA") value.So, for detailed analysis in octave frequency bands, textbook information is still usually required, in terms o f the spectral weightings needed to apportion the single dBA level into its component octave band sound levels.Unfortunately, the information in the published reference texts varies enormously with regard to the suggested spectral weighting corrections.The corrections in some texts are internally inconsistent, and the discrepancy among different texts (even those which cite the same primary references) is severe enough to call the whole body of data into question.This paper enumerates the inconsistencies and discrepancies within and among several commonly used acoustical engineering text books and compares the textbook levels to a wide body o f data collected at numerous outdoor transformer installations throughout Ontario.Suggestions are provided for realistic spectral weightings and sound level estimates for transformers, on the basis of the measured data. r é s u m éLe point de départ typique lors du processus de prédiction des émissions sonores d'un futur transformateur est d'obtenir des données de niveaux sonores du fabricant ou de développer une estimation en utilisant des équations de prédiction génériques à partir d'un manuel publié.Si des données de niveaux sonores sont disponibles auprès du fabricant de transformateur -qu'elle soit mesurées ou estimées -elles le sont généralement seulement en termes de valeurs pondérées selon la courbe A. («dBA»).Ainsi, pour une analyse détaillée par bandes d'octaves, il est habituellement nécessaire de convertir une valeur dBA avec l'aide d'une pondération spectrale suggérée par un manuel publié.Malheureusement, les informations contenues dans les textes de référence publiés varient énormément en ce qui concerne les corrections suggérées pour la pondération spectrale.Les corrections dans certains textes sont en soi incompatibles, et l'écart entre les différents textes (même ceux qui citent les mêmes références primaires) mérite d'appeler l'ensemble des données en question.Ce document énumère les contradictions et les divergences au sein et entre plusieurs manuels d'ingénierie acoustique couramment utilisés et compare les manuels publiés à un vaste ensemble de données de transformateur à ciel ouvert collectées en Ontario.Des suggestions réalistes, basées sur les données mesurées, sont fournies à titre de coefficients spectraux et d'estimations de niveaux sonores pour les transformateurs.
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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 | 0.003 | 0.016 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
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".