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Abstract

Conversational question answering (ConvQA) tackles sequential information
needs where contexts in follow-up questions are left implicit. Current ConvQA
systems operate over homogeneous sources of information: either a knowledge
base (KB), or a text corpus, or a collection of tables. This paper addresses
the novel issue of jointly tapping into all of these together, this way
boosting answer coverage and confidence. We present CONVINSE, an end-to-end
pipeline for ConvQA over heterogeneous sources, operating in three stages: i)
learning an explicit structured representation of an incoming question and its
conversational context, ii) harnessing this frame-like representation to
uniformly capture relevant evidences from KB, text, and tables, and iii)
running a fusion-in-decoder model to generate the answer. We construct and
release the first benchmark, ConvMix, for ConvQA over heterogeneous sources,
comprising 3000 real-user conversations with 16000 questions, along with entity
annotations, completed question utterances, and question paraphrases.
Experiments demonstrate the viability and advantages of our method, compared to
state-of-the-art baselines.