Experimental Study of the Low-Frequency Noise Characteristics of Empty and Fitted Workshops
Bibliographic record
Abstract
In order to investigate the temporal and steady-state low-frequency characteristics of sound in industrial workshops, measurements were made of reverberation times and sound-pressure levels in a machine shop and in a 1/8-scale-model workshop when empty and fitted. Low-frequency pure tones and octave-band noise were used as the source excitation. Fittings generally reduced reverberation times. In the empty machine shop, levels showed strong spatial variations due to modal effects, as expected. When fitted with machine tools, levels changed by up to 20 dB, and local variations increased, despite the fittings being small compared to the sound wavelengths. In the scale model, smaller and larger fittings were tested. Results for the model when empty and when fitted with the larger fittings were similar to those in the machine shop. With the smaller fittings, the results suggested that fittings can act to diffuse sound, reducing spatial variations. Tests were also done in an empty and fitted hemi-anechoic chamber to study the effect of fittings in the absence of the room. Fittings alone only slightly affected the sound field, demonstrating that modal effects are predominantly due to the room, possible modified by the presence of fittings.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".