In our approach, we use an attentive Seq2Seq rerank model to optimize the joint results.
for a question, we first use an IR model to retrieve a set of QA pairs and use them as candidate answers, and then rerank the candidate answers using an attentive Seq2Seq model: if the top candidate has a score higher than a certain threshold, it will be taken as the answer; otherwise the answer will be offered by a generation based model (see Fig.