Pre-training Transformer Models With Sentence-level Objectives For Answer Sentence Selection

Di Liello Luca, Garg Siddhant, Soldaini Luca, Moschitti Alessandro. Arxiv 2022

[Paper]    
BERT Model Architecture Pretraining Methods RAG Training Techniques Transformer

An important task for designing QA systems is answer sentence selection (AS2): selecting the sentence containing (or constituting) the answer to a question from a set of retrieved relevant documents. In this paper, we propose three novel sentence-level transformer pre-training objectives that incorporate paragraph-level semantics within and across documents, to improve the performance of transformers for AS2, and mitigate the requirement of large labeled datasets. Specifically, the model is tasked to predict whether: (i) two sentences are extracted from the same paragraph, (ii) a given sentence is extracted from a given paragraph, and (iii) two paragraphs are extracted from the same document. Our experiments on three public and one industrial AS2 datasets demonstrate the empirical superiority of our pre-trained transformers over baseline models such as RoBERTa and ELECTRA for AS2.

Similar Work