Sensitivity Analysis of an Evolutionary-Based Time-Dependent Origin/Destination Estimation Framework
Bibliographic record
Abstract
This paper presents sensitivity analysis results for a distributed evolutionary implementation of the estimation of time-dependent origin-destination (TDOD) matrices. The system uses a noniterative origin-destination (OD) estimation process, which attempts to minimize the discrepancy between observed link flow counts and assigned counts. At the same time, the system anchors the search process to the vicinity of an a priori OD matrix to maintain travel patterns and OD structure. The sensitivity analysis examines various factors that are expected to affect the performance of the evolutionary-based TDOD estimation method. The factors examined are congestion levels, network size, size of the search space, and degree of precision of the a priori matrix. Simulation results for the waterfront network in Toronto, ON, Canada, show that the algorithm is robust in terms of replicating observed vehicle counts and the closeness to the real demand. The use of distributed evolutionary algorithm is also shown to provide good results for a large network and within fast computing speeds. However, the quality of the estimated OD relative to the true OD is shown to deteriorate if a totally random a priori matrix is used as a starting point, which has no structural resemblance to the prevailing OD patterns in the network. In addition, the quality of the estimated OD matrix was found to deteriorate as congestion levels and the network size increased. It is notable that, in all cases, the estimated OD matrix resulted in better matching flows.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".