Comparison of Machine Learning Methods for Human Activity Recognition Using Pseudo Free-Living Data
Bibliographic record
Abstract
Recognition of human activities has become more critical in recent years. Practical approaches for classifying physical activities are becoming required in the scientific community, and such models are needed explicitly in health promotion and behavior. The data collected in real-world conditions differ from laboratory data, which has been the main focus of much research. As a result, in this work, we analyzed several machine-learning techniques and models for identifying human activity using a pseudo-free-living dataset obtained at the University of Georgia. We found that hierarchical meta-classifiers outperformed deep learning and classical models by 6% for classifying seven activities. Model personalization is promoted since it lowers the inter-subject variability of the dataset. We divided activities based on the Metabolic Equivalent of Task (MET), and we achieved 80% inter-subject accuracy and 87% accuracy by including 50% of the participant's data. Achieving high performance for machine learning models is challenging using real-world data.
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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 | 0.006 | 0.013 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".