Hierarchical Modeling of Pipeline Defect Growth Subject to ILI Uncertainty
Bibliographic record
Abstract
Pipeline deterioration arises chiefly as the result of various types of internal and external corrosion processes, which are typically subject to several uncertainties. They include material uncertainties, uncertainties in external influences such as loading and environmental variations, uncertainties in operating conditions, various spatial and temporal uncertainties, inspection uncertainties, and modeling uncertainties. Typically, the metal loss time-path at one defect feature may be quite different from the metal loss time-path in a neighboring location even when subject to supposedly similar loading, material and environmental circumstances. On top of that, in-line inspections (ILI) of pipeline systems affected by deterioration are performed infrequently and suffer from considerable uncertainty due to sizing errors and detectability. The present paper provides a Hierarchical Bayes framework for corrosion defect growth. While a full Hierarchical Bayes analysis is practical only for selected critical defect features, we also develop a simplified method based on multi-level generalized least squares. The latter method is useful for scanning large defect inspection data sets. Two detailed examples of the approach are presented.
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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 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".