PolyU IR
 

PolyU Institutional Repository >
Computing >
COMP Theses >

Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/973

Title: Finding and estimating near optimal queries
Authors: Wong, Wing-sze
Subjects: Information retrieval
Information storage and retrieval systems
Machine learning
Hong Kong Polytechnic University -- Dissertations
Issue Date: 2007
Publisher: The Hong Kong Polytechnic University
Abstract: The ultimate objective of IR systems is to obtain optimal retrieval effectiveness. However, the best MAP values of the state-of-the-art IR systems are typically below 35% in the ad hoc automatic retrieval of TREC evaluations. This value is still far below the theoretical optimal retrieval effectiveness of 100%. In this study, we investigate whether it is possible to achieve near optimal retrieval effectiveness using the existing IR systems by formulating effective queries. These effective queries are called near optimal queries because they lead the IR systems to achieve near optimal retrieval effectiveness. Our near optimal queries are defined so as not to include the trivially good effective terms. We propose two strategies, the Idealized Relevance Feedback, and the Combinatorial Optimization Search, to find the near optimal queries under some idealized conditions. We have experimented with a substantial number of query-formulating methods based on the strategies and have evaluated these by using TREC test collections. The best MAP values of our near optimal queries for TREC-6, TREC-7 and TREC-8 test collections are 73%, 76% and 75%, respectively. It appears that a suitable choice of terms and a suitable choice of weights can substantially enhance the retrieval effectiveness of the existing IR systems. Based on the observations of the terms in the near optimal queries, we develop a classifier to estimate a near optimal query. The experimental results show that our classifier can improve the retrieval effectiveness of the user query in existing IR systems.
Degree: M.Phil., Dept. of Computing, The Hong Kong Polytechnic University, 2007.
Description: xii, 136 p. : ill. ; 31 cm.
PolyU Library Call No.: [THS] LG51 .H577M COMP 2007 Wong
Rights: All rights reserved.
Type: Thesis
URI: http://hdl.handle.net/10397/973
Appears in Collections:COMP Theses
PolyU Electronic Theses

Files in This Item:

File Description SizeFormat
b20940464_ir.pdfFor All Users (Non-printable)2.98 MBAdobe PDFView/Open
b20940464_link.htmFor PolyU Users167 BHTMLView/Open



Facebook Facebook del.icio.us del.icio.us LinkedIn LinkedIn


All items in the PolyU Institutional Repository are protected by copyright, with all rights reserved, unless otherwise indicated.
No item in the PolyU IR may be reproduced for commercial or resale purposes.

 

© Pao Yue-kong Library, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
Powered by DSpace (Version 1.5.2)  © MIT and HP
Feedback | Privacy Policy Statement | Copyright & Restrictions - Feedback