Please note: This PhD seminar will take place online.
Ji
Xin,
PhD
candidate
David
R.
Cheriton
School
of
Computer
Science
Supervisors: Professors Jimmy Lin, Yaoliang Yu
Dense retrieval methods conduct text retrieval by first encoding texts in the embedding space and then matching them by nearest neighbor search. This requires strong locality properties from the representation space, e.g., close allocations of each small group of relevant texts, which are hard to generalize to domains without sufficient training data.
In this paper, we aim to improve the generalization ability of dense retrieval models from source training domains with rich supervision signals to target domains without any relevance label, in the zero-shot setting. To achieve that, we propose momentum adversarial domain invariant representation learning, which introduces a momentum method to train a domain classifier that distinguishes source versus target domains, and then adversarially updates the dense retrieval encoder to learn domain invariant representations. Our experiments show that our model robustly outperforms its baselines on 10+ ranking datasets collected in the BEIR benchmark in the zero-shot setup, with more than 10% relative gains on datasets with enough sensitivity for DR models’ evaluation.
To join this PhD seminar on Zoom, please go to https://uwaterloo.zoom.us/j/94349250988.