OPEN LANGUAGE LEARNING FOR INFORMATION EXTRACTION
Open Information Extraction (IE) systems extract relational tuples from text, without requiring a pre-specified vocabulary, by identifying relation phrases and associated arguments in arbitrary sentences. However, state-of-the-art Open IE systems such as R E V ERB and WOE share two important weaknesses—(1) they extract only relations that are mediated by verbs, and (2) they ignore context, thus extracting tuples that are not asserted as factual. This paper presents OLLIE , a substantially improved Open IE system that addresses both these limitations. First, OLLIE achieves high yield by extracting relations mediated by nouns, adjectives, and more. Second, a context-analysis step increases precision by including contextual information from the sentence in the extractions. OLLIE obtains 2.7 times the area under precision-yield curve (AUC) compared to R E V ERB and 1.9 times the AUC of WOE parse .
1 . A method for learning open patterns within a corpus of text, the method comprising:
for seed tuple and sentence pairs, creating a candidate pattern by:
extracting a dependency path of the sentence connecting the words of the arguments and the relation of the seed tuple; and
annotating dependency path with the word of the relation and a part-of-speech constraint; and
when a candidate pattern is a syntactic pattern, generalizing the candidate pattern to unseen relations and preposition to generate an open pattern; and
when a candidate pattern is not a syntactic pattern, converting lexical constraints of the candidate patterns with similar syntactic restrictions on the relation word into a list of words of sentences with the candidate pattern to generate an open pattern.