Fast and accurate 3-D ray tracing using bilinear traveltime interpolation and the wave front group marching
Bibliographic record
Abstract
We propose a new ray tracing technique in a 3-D heterogeneous isotropic media based on bilinear traveltime interpolation and the wave front group marching. In this technique, the media is discretized into a series of rectangular cells. There are two steps to be carried out: one is a forward step where wave front expansion is evolved from sources to whole computational domain and the subsequent one is a backward step where ray paths are calculated for any source–receiver configuration as desired. In the forward step, we derive a closed-form expression to calculate traveltime at an arbitrary point in a cell using a bilinear interpolation of the known traveltimes on the cell's surface. Then the group marching method (GMM), a fast wave front advancing method, is applied to expand the wave front from the source to all girds. In the backward step, ray paths starting from receivers are traced by finding the intersection points of potential ray propagation vectors with the surfaces of relevant cells. In this step, the same TI scheme is used to compute the candidate intersection points on all surfaces of each relevant cell. In this process, the point with the minimum traveltime is selected as a ray point from which the similar step is continued until sources. A number of numerical experiments demonstrate that our 3-D ray tracing technique is able to achieve very accurate computation of traveltimes and ray paths and meanwhile take much less computer time in comparison with the existing popular ones like the finite-difference-based GMM method, which is combined with the maximum gradient ray tracing, and the shortest path method.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| 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".