Improved Random Walk Method Verified in a Large-Scale Urban Network for the Sampling of Alternatives in Route Choice Modeling
Bibliographic record
Abstract
The first stage in route choice modeling is the generation of the route choice sets, which directly affects the accuracy of model estimation. The random walk method proposed by Frejinger et al. for this purpose has the advantage of directly calculating the probabilities of paths chosen. However, its application has seldom been seen in a large-scale network of a real large city in the literature. To fill this gap, the performance of the random walk algorithm is examined on a real network in Shanghai, China. It is found that it cannot avoid loops and frequently produces overlong alternative paths. By locating the root cause, an improved random walk algorithm is proposed in this paper. The idea of the new algorithm is to change the value of the shape parameters. Instead of a fixed value in Frejinger et al.’s method, the shape parameter in this approach is dynamically changing, controlled by the allowable probability difference and generalized minimum cost. The algorithm is validated in a large-scale network using real travel survey data. The results of the empirical analysis suggest that the proposed random walk algorithm has a significant improvement with respect to the number and length of generated alternative paths compared to those from the original algorithm. This study's primary contribution is to significantly improve the adaptability of the random walk method in large-scale road networks, which is crucial for improving the accuracy of route choice models and understanding of route choice behaviors.
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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 | 0.010 |
| 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 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| 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".