3,698 research outputs found
Retrospective Reader for Machine Reading Comprehension
Machine reading comprehension (MRC) is an AI challenge that requires machine
to determine the correct answers to questions based on a given passage. MRC
systems must not only answer question when necessary but also distinguish when
no answer is available according to the given passage and then tactfully
abstain from answering. When unanswerable questions are involved in the MRC
task, an essential verification module called verifier is especially required
in addition to the encoder, though the latest practice on MRC modeling still
most benefits from adopting well pre-trained language models as the encoder
block by only focusing on the "reading". This paper devotes itself to exploring
better verifier design for the MRC task with unanswerable questions. Inspired
by how humans solve reading comprehension questions, we proposed a
retrospective reader (Retro-Reader) that integrates two stages of reading and
verification strategies: 1) sketchy reading that briefly investigates the
overall interactions of passage and question, and yield an initial judgment; 2)
intensive reading that verifies the answer and gives the final prediction. The
proposed reader is evaluated on two benchmark MRC challenge datasets SQuAD2.0
and NewsQA, achieving new state-of-the-art results. Significance tests show
that our model is significantly better than the strong ELECTRA and ALBERT
baselines. A series of analysis is also conducted to interpret the
effectiveness of the proposed reader.Comment: Accepted by AAAI 202
Simple and Effective Curriculum Pointer-Generator Networks for Reading Comprehension over Long Narratives
This paper tackles the problem of reading comprehension over long narratives
where documents easily span over thousands of tokens. We propose a curriculum
learning (CL) based Pointer-Generator framework for reading/sampling over large
documents, enabling diverse training of the neural model based on the notion of
alternating contextual difficulty. This can be interpreted as a form of domain
randomization and/or generative pretraining during training. To this end, the
usage of the Pointer-Generator softens the requirement of having the answer
within the context, enabling us to construct diverse training samples for
learning. Additionally, we propose a new Introspective Alignment Layer (IAL),
which reasons over decomposed alignments using block-based self-attention. We
evaluate our proposed method on the NarrativeQA reading comprehension
benchmark, achieving state-of-the-art performance, improving existing baselines
by relative improvement on BLEU-4 and relative improvement on
Rouge-L. Extensive ablations confirm the effectiveness of our proposed IAL and
CL components.Comment: Accepted to ACL 201
Controlling Risk of Web Question Answering
Web question answering (QA) has become an indispensable component in modern
search systems, which can significantly improve users' search experience by
providing a direct answer to users' information need. This could be achieved by
applying machine reading comprehension (MRC) models over the retrieved passages
to extract answers with respect to the search query. With the development of
deep learning techniques, state-of-the-art MRC performances have been achieved
by recent deep methods. However, existing studies on MRC seldom address the
predictive uncertainty issue, i.e., how likely the prediction of an MRC model
is wrong, leading to uncontrollable risks in real-world Web QA applications. In
this work, we first conduct an in-depth investigation over the risk of Web QA.
We then introduce a novel risk control framework, which consists of a qualify
model for uncertainty estimation using the probe idea, and a decision model for
selectively output. For evaluation, we introduce risk-related metrics, rather
than the traditional EM and F1 in MRC, for the evaluation of risk-aware Web QA.
The empirical results over both the real-world Web QA dataset and the academic
MRC benchmark collection demonstrate the effectiveness of our approach.Comment: 42nd International ACM SIGIR Conference on Research and Development
in Information Retrieva
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