A Computational Model for Determining the Optimal Preventive Maintenance Policy With Random Breakdowns and Imperfect Repairs
Bibliographic record
Abstract
We consider a system that is subject to random failures, and investigate the decision rule for performing renewal maintenance or preventive replacement (PR). This type of maintenance policy involves two decision variables. The first decision variable is the time between preventive replacements, or a fixed cycle time. To avoid unnecessary renewals or replacements at the end of a cycle, a cut-off age is introduced as the second decision variable. At the end of every cycle, if the system's virtual age is equal to or greater than the cut-off age, it will undergo a renewal or replacement; otherwise the renewal decision will be postponed until the end of the next cycle. Random failures can occur, however; and the system receives emergency imperfect repairs (ER) at these times. Hence, within a PR cycle, a second decision time is identified. If an ER occurs between the start of a cycle and this second decision time, then the planned PR would still be performed at the end of the cycle. However, if the first ER occurs after this second decision time, then the PR at the end of the cycle is skipped over, and the next planned PR would take place at the end of the subsequent cycle. With this simple mechanism, PR which follow on too closely after an ER are avoided, thus saving the unnecessary expense. We develop a computational model to determine the optimal maintenance policy with these two decision variables
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".