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New England Database
Society sponsored by Sun Microsystems |
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NEDS |
Similarity-based Search of Time Series and Trajectory Data
M. Tamer Ozsu
University
of Waterloo, Canada
Friday, May 20, 2005, 4:00
PM
Volen 101, Brandeis
University
(preceded by a wine and cheese reception at 3:00 pm)
Abstract:
Time series data have been used in many applications, such as financial data analysis and weather forecasting. Similarly, trajectories of moving objects are often used to perform movement pattern analysis in surveillance video and sensor monitoring systems. These applications require finding, from among a large set of time series or trajectory data, those that are similar to a query data (the similarity-based retrieval problem). Most of this data are unclean, containing local time shifting and noise, while most of the work in this area has developed techniques that work on clean data. In this talk, I address similarity-based retrieval of time series and trajectory data in the presence of local time shifting and noise. In particular, I will present two novel distance functions: metric distance function, called Edit distance with Real Penalty (ERP), that can support local time shiftin, and, Edit Distance on Real sequence (EDR) that can handle noise as well as local time shifting, but is not metric. Since the proposed distance functions are computationally expensive, I propose several indexing and pruning methods to improve the retrieval efficiency. For ERP, a framework is developed to index time series or trajectory data under a metric distance function, which exploits the pruning power of lowering bounding and triangle inequality. For EDR, three pruning techniques mean value Q-grams, near triangle inequality, and trajectory histograms are developed to improve the retrieval efficiency.
Joint work with Lei chen.
Speaker Bio:
M. Tamer Özsu is a Professor of Computer Science and University Research Chair at the University of Waterloo. His current research focuses on three areas: (a) Internet-scale data distribution that emphasizes stream data management and peer-to-peer databases; (b) multimedia data management, concentrating on similarity-based retrieval of time series and trajectory data; and (c) structured document management mainly within the context of XML query processing and optimization.
He is the current Chair of ACM SIGMOD and the Coordinating Editor-in-Chief of The VLDB Journal. He also serves on the editorial boards of ACM Computing Surveys, Distributed and Parallel Databases Journal, World Wide Web Journal, Information Technology and Management, and Springer Book Series on Advanced Information & Knowledge Processing. He has served as the Program Chair of VLDB (2004), WISE (2001), IDEAS (2003), and CIKM (1996) conferences and the General Chair of CAiSE (2002) conference. He will serve as the co-PC chair of ICDE 2007 to be held in Istanbul, Turkey.
Maintained by Dina Goldin dqg AT cse.uconn.edu