Limitation of using absorbing boundary condition to solve the problem of scattering from a cavity in metallic screens
Bibliographic record
Abstract
In this study, we reviewed the methods used to truncate the solution region of infinite structures while using FEM and highlight the inherent limitation in truncation the infinite structure using local boundary operators such as ABC or PML in the context of the problem of scattering from infinite gratings. It is showed that there is inherent error in the solution due to the truncation of the solution region and ignoring the portion of PEC walls located outside the solution region. Numerical example of single cavity engraved in an infinite PEC wall were presented to calculate the error in field computation using the ABC as local boundary condition. The root mean square error in field computation using ABC is calculated for the FEMbased method using non-local boundary condition and mode matching technique as the accurate solutions. We showed that the error in the solution due to truncation increases exponentially as the incident angle increases. Also we showed that the error decreases by receding the boundary but can not be eliminated completely since the ABC is inefficient to enclose the infinite scatterer body. However it results in prohibitive increase of the computational cost and resources.
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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 | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".