Sepia : semantic parsing for named entities

People's names, dates, locations, organizations, and various numeric expressions, collectively called Named Entities, are used to convey specific meanings to humans in the same way that identifiers and constants convey meaning to a computer language interpreter. Natural Language Question Answering can benefit from understanding the meaning of these expressions because answers in a text are often phrased differently from questions and from each other. For example, "9/11" might mean the same as "September 11th" and "Mayor Rudy Giuliani" might be the same person as "Rudolph Giuliani". Sepia, the system presented here, uses a lexicon of lambda expressions and a mildly context-sensitive parser to create a data structure for each named entity. The parser and grammar design are inspired by Combinatory Categorial Grammar. The data structures are designed to capture semantic dependencies using common syntactic forms. Sepia differs from other natural language parsers in that it does not use a pipeline architecture. As yet there is no statistical component in the architecture. To evaluate Sepia, I use examples tp illustrate its qualitative differences from other named entity systems, I measure component performance on Automatic Content Extraction (ACE) competition held-out training data. and I assess end-to-end performance in the Infolab's TREC-12 Question Answering competition entry. Sepia will compete in the ACE Entity Detection and Tracking track at the end of September.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Marton, Gregory A. (Gregory Adam), 1977-

Advisor dc:contributor.advisor

• Boris Katz.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/28336

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/28336