Einladung zum Informatik-Kolloquium

======================================

Datum und Zeit: Dienstag, 19. Juni 2012 - 16:00 Uhr

Raum: L 155, Oettingenstraße 67

Es spricht: Prof. Dr. Reynold Cheng

Über: Evaluating Probabilistic Queries over Uncertain Matching


Abstract:
A matching between two database schemas generated by machine learning techniques (e.g., COMA++) is often uncertain. Handling the uncertainty of schema matching has recently raised a lot of research interest, because the quality of applications relies on the matching result. We study query evaluation over an inexact schema matching which is represented as a set of "possible mappings", as well as the probabilities that they are correct. Since the number of possible mappings can be large, evaluating queries through these mappings can be expensive. By observing that the possible mappings between two schemas often exhibit a high degree of overlap, we develop two efficient solutions. We also present a fast algorithm to compute answers with the k highest probabilities. An extensive evaluation on real schemas shows that our approaches improve query performance by almost an order of magnitude.

Bio:

Dr. Reynold Cheng is an Associate Professor of the Department of Computer Science in the University of Hong Kong. He was an Assistant Professor in HKU in 2008-11. He received his BEng (Computer Engineering) in 1998, and MPhil (Computer Science and Information Systems) in 2000, from the Department of Computer Science in the University of Hong Kong. He obtained his MSc and PhD from Department of Computer Science of Purdue University in 2003 and 2005 respectively. Dr. Cheng was an Assistant Professor in the Department of Computing of the Hong Kong Polytechnic University during 2005-08. He was a visiting scientist in the Institute of Parallel and Distributed Systems in the University of Stuttgart during the summer of 2006.

Dr. Cheng was the recipient of the 2010 Research Output Prize in the Department of Computer Science of HKU. He also awarded the U21 Fellowship in 2011. He received the Performance Reward in years 2006 and 2007 awarded by the Hong Kong Polytechnic University. He is the Chair of the Department Research Postgraduate Committee, and is the Vice Chairperson of the ACM (Hong Kong Chapter). He is a member of the IEEE, the ACM, the Special Interest Group on Management of Data (ACM SIGMOD), the UPE (Upsilon Pi Epsilon Honor Society). He is an editorial member of the DAPD journal. He was also a guest editor in TKDE. He received an Outstanding Service Award in the CIKM 2009 conference. He has served as PC members and reviewer for international conferences and journals including TODS, TKDE, TMC, VLDBJ, IS, DKE, DAPD, KAIS, VLDB, ICDE, ICDM, and DASFAA.