An Online Sequential Update Method for Reduced-Order-Model-Based Digital Twin
Bibliographic record
Abstract
Abstract Digital twin (DT) refers to any model that reflects a physical system and remains updated with the real-time data from the physical system. Recently, DT constructed with a reduced-order model (DT-ROM) has been applied to aerodynamics and structure health monitoring tasks, whose partial differential equations (PDEs) are used to design the online update formula for reduced bases and coefficients in DT-ROM. Although such online update methods improve the performance of DT-ROM, they are not applicable when the PDEs of a system are unknown. This paper focuses on the online update task where a system is modeled with a DT-ROM, but the system’s PDEs are unknown. To tackle the task, an online sequential update method is proposed. During the update process, the projection residual of online data on the reduced bases is applied to determine whether to update the reduced bases in ROM, and the prediction residual of online data obtained by the offline DT-ROM is adopted to infer whether to update the coefficient models. By checking both criteria sequentially, the online update method selects the necessary online data for the DT update. Three numerical problems and one engineering problem are designed to test the proposed online update method. Testing results demonstrate that (a) the proposed online update method reduces both the projection and prediction residuals gradually, and (b) the performance of the offline DT-ROM model on the testing data is improved gradually during the online update process. Both indicate that the proposed method could be applied to online DT update tasks where the PDEs of the system are unknown.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".