An efficient soft computing-based calibration method for microscopic simulation models
Bibliographic record
Abstract
In recent years, vehicular microscopic simulation models have become one of the main tools used by transportation professionals to analyze transportation policies and projects. Effective use of the existing simulation packages is limited by the calibration of specific parameters based on observed real-life conditions. However, because the calibration of the packages is a resource-intensive process, one might resort to using the default parameter values. In this study, a soft-computing based methodology is proposed that considerably reduces the computation time in comparison to other commonly used methods. The proposed methodology is based on a synergistic combination of artificial neural networks (ANN) and genetic algorithms (GA). First, a Latin hypercube sampling method is used to select representative sets of values for the simulation model's calibration parameters. Second, the effect of each set of parameter values on the simulated traffic stream speed is evaluated. Third, an ANN is trained to determine the relationship between the input parameter values and the output vehicular speed. Finally, a genetic algorithm uses the trained ANN to determine the calibration parameters. Applications of the proposed methodology shows that it allows for less time-consuming calibration of microscopic traffic models compared to other commonly used methods.
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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 | 0.001 | 0.001 |
| Open science | 0.001 | 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".