Conversation Trees: A Grammar Model for Topic Structure in Forums
Annie Louis, Shay B. Cohen · 2015
Online forum discussions proceed differently from face-to-face conversations and any single thread on an online forum contains posts on different subtopics.This work aims to characterize the content of a forum thread as a conversation tree of topics.We present models that jointly perform two tasks: segment a thread into subparts, and assign a topic to each part.Our core idea is a definition of topic structure using probabilistic grammars.By leveraging the flexibility of two grammar formalisms, Context-Free Grammars and Linear Context-Free Rewriting Systems, our models create desirable structures for forum threads: our topic segmentation is hierarchical, links non-adjacent segments on the same topic, and jointly labels the topic during segmentation.We show that our models outperform a number of tree generation baselines.