{'fraction_non_alphanumeric': 0.012640449438202247, 'fraction_numerical': 0.004213483146067416, 'mean_word_length': 5.601851851851852, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A Comparative Study on Sentence Retrieval for Definitional Question Answering

Most definitional question answering (QA) systems integrate statistical ranking using Web and WordNet as external resources and pattern matching to retrieve relevant sentences for further processing. We examine the impact of using these two common resources in answering definition questions by varying the use of WordNet and two types of Web resources in statistical ranking, and definition pattern modules in a typical definitional QA system. In particular, we show that an appropriate combination of Webreinforced ranking and soft matching pattern produces an unsupervised system that outperforms the best system at TREC-12 by 6%.