Comparison of surrogate 50th percentile human headforms to an adult male sample using three-dimensional modeling and principal component analysis
Bibliographic record
Abstract
Ice hockey helmets are required to be impact tested while mounted to a surrogate 50th percentile adult male headform. However, head shape and size can vary substantially from user to user. Furthermore, the contact area between a headform and helmet interior has been identified as an important factor affecting the protective capabilities of a helmet. The objective of this study was to compare quantitative measures of head shapes between three 50th percentile adult male headforms and a sample of adult human subjects who wore a medium-sized helmet. Using three-dimensional models of the human subjects and headforms, head shape was quantified by assessing radial distances in two transverse planes of the head and by using principal component analysis to determine the largest components of fit. Notable differences were found between the headforms and human subjects. The headforms were smaller than the human subjects, demonstrating smaller radial distances for the entire head. The principal components of head shape were overall size and roundness of the head. The results of this study demonstrate the headforms are not representative of the sample median.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.002 | 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".