Lexical Paraphrasing for Document Retrieval and Node Identification

We investigate lexical paraphrasing in the context of two distinct applications: document retrieval and node identification. Document retrieval – the first step in question answering – retrieves documents that contain answers to user queries. Node identification – performed in the context of a Bayesian argumentation system – matches users’ Natural Language sentences to nodes in a Bayesian network. Lexical paraphrases are generated using syntactic, semantic and corpus-based information. Our evaluation shows that lexical paraphrasing improves retrieval performance for both applications.