University of Waterloo at TREC 2015 Microblog Track
Bibliographic record
Abstract
Given a topic with title, narrative and description, we start by building a language model for the topic. The top 1000 tweets were retrieved from Twitter commercial search engine by applying the title of the topic as a query. We exploit pseudo relevance feedback technologies to estimate probability distributions of each term in the topic, then comparing these probabilities with a background distribution model. We select the highest dierent terms as our expanded query terms. We then generate a vector for each topic, the features of the vector are non-stop word title terms, selected narrative terms and query expansion terms. Dierent weights are assigned to the dierent types of terms. Since we are allowed to deliver at most 10 tweets every day, and the latency time can not exceed 100 minutes, we solve the tweet notication scenario as a multiple-choice secretary problem. Two dierent solutions were tested.
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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 | 0.006 | 0.012 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.006 | 0.006 |
| Science and technology studies | 0.004 | 0.001 |
| Scholarly communication | 0.006 | 0.007 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.084 | 0.058 |
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".