Approaches to big data analysis of interface pressure measurements from continuous pressure imaging technology
Bibliographic record
Abstract
IntroductionOver 4.5 TB of data will be collected in a randomized clinical trial assessing continuous pressure imaging technology in reducing pressure injuries. To permit efficient analysis we examined different approaches to generating a reduced representation of the data that still produced similar analytical results to the full data set.
 Objectives and ApproachOur primary objective was to develop an approach for reducing the pressure data to a manageable size, without loss of information. Frame by frame analysis of excluded participant imaging data allows us to identify changes in patient position. We explored different sampling frequencies (q5, 30, 60, 120, \& 240 seconds) for analysis, coalesced frames with periods of stillness, and used correlation coefficients as a measure of similarity between adjacent frames to identify patient position changes. Heat maps and plots were used to evaluate the performance characteristics and usefulness of different sampling frequencies and correlation coefficients to compress the data.
 ResultsA sampling frequency q60 seconds provided reasonable representation of changes in interface pressure over time. This translates to using only 1.7\% of the collected data in our analyses. When the threshold of correlation coefficient was set at 0.99 for coalescing the information based on position changes, then there was a maximum of 80 position changes detected. Therefore, approximately 160 frames q24 hours is sufficient to represent pressure states of participants at high risk of developing pressure injuries. In total we would require 480 frames (160*3) from 72 hours of collected data for our analyses without loss of position changes and pressure information. This represents approximately 0.185\% of the data collected.
 Conclusion/ImplicationsDecreasing the sampling frequency significantly reduced our data size without compromising resolution, while the use of correlation coefficients was effective at coalescing the continuous pressure imaging data. These methods of data reduction may be applicable to pre-processing large datasets obtained from other device monitoring technologies.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.003 | 0.001 |
| 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".