Topic-Oriented Dialogue Summarization.

A multi-turn dialogue often contains multiple discussion topics. In several scenarios (e.g., customer service dispute, public opinion monitoring), people are only interested in the gist of a specific topic in the dialogue. Therefore, we propose a novel summarization task, i.e., Topic-Oriented Dialogue Summarization (TODS). Given a dialogue with a topic label, TODS aims to produce a summary covering the main content of the given topic in the dialogue. To model the relationship between dialogues and topics, three key abilities are needed for TODS: (1) Learning the semantic information of different topics. (2) Locating the topic-related content in the dialogue. (3) Distinguishing summaries for different topics in the same dialogue. Thus, we propose three topic-related auxiliary tasks to make the summarization model learn the three abilities above. First, the topic identification task aims at generating all the topics in the dialogue. Second, the topic attention restriction task tries to constrain the attention distribution on topic-related utterances. Third, the topic summary distinguishing task focuses on increasing the difference of summaries for different topics in the same dialogue. Experimental results on two public TODS datasets show that all auxiliary tasks are critical for TODS and help generate high-quality summaries. We also point out the expansions and challenges in TODS for future research.