Mitigating the Curse of Dimensionality for Exact kNN Retrieval
Bibliographic record
Abstract
Efficient data indexing and exact k-nearest-neighbor (kNN) retrieval are still challenging tasks in high-dimensional spaces. This work highlights the difficulties of indexing in high-dimensional and tightly-clustered dataspaces by exploring several important tunable parameters for optimizing kNN query performance using the iDistance and iDStar algorithms. We experiment on real and synthetic datasets of varying size, cluster density, and dimensionality, and compare performance primarily through filter-and-refine efficiency and execution time. Results show great variability over parameter values and provide new insights and justifications in support of prior best-use practices. Local segmentation with iDStar consistently outperforms iDistance in any clustered space below 256 dimensions, setting a new benchmark for efficient and exact kNN retrieval in high-dimensional spaces. We propose several directions of future work to further increase performance in high-dimensional real-world settings.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.008 | 0.044 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.003 | 0.005 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.005 | 0.010 |
| Open science | 0.003 | 0.004 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
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".