Treffer: Natural language information retrieval : TREC-3 report

In this paper we report on the recent developments in NYU's natural language information retrieval system especially as related to the 3rd Text Retrieval conference (TREC-3). The main characteristic of this system is the use of advanced natural language processing to enhance the effectiveness of term-based document retrieval. The system is designed around a traditional statiscal backbone consisting of the indexer module, which builds inverted index files from pre-processed documents, and a retrieval engine which searches and ranks the documents in response to user queries. Natural language processing is used to (1) preprocess the documents in order to extract content-carrying terms, (2) discover inter-term dependencies and build a conceptual hierarchy specific to the database domain, and (3) process user's natural language requests into effective search queries. For the present TREC-3 effort, the total of 3.3 GBytes of text articles have been processed (Tipster disks 1 through 3), including material from the Wall Street Journal, the Associated Press newswire, the Federal Register, Ziff Communication's Computer Library, Department of Energy abstract, U.S. Patents and the San Jose Mercury News, totaling more than 500 million words of English. Since the TREC-2 conference, many components of the system have been redesigned to facilitate its scalability to deal with ever increasing amounts of data. In particular, a randomized index-splitting mechanism has been installed which allows the system to create a number of smaller indexes that can be independently searched.