My interests are in the areas of databases, information retrieval, data
mining, and Web. I work on data/information retrieval and exploration,
ranking and top-k queries, query processing and optimization, Web data search,
management and integration, and XML query processing. In my PhD work I built a
"Google" for databases. The system, RankSQL, is built inside the kernel
of a full-fledged DBMS, PostgreSQL. It enables intuitive, efficient, and robust
data retrieval by ranking and mechanisms beyond ranking. It helps users to
efficiently retrieve data by non-traditional fuzzy queries with soft criteria,
and to explore what choices are available in databases and how they match the
query criteria. This line of work has broad applications in many domains
including E-commerce, Web search, multimedia retrieval, health data management,
and bioinformatics.
A Structure-Driven Yield-Aware Web Form
Crawler:
Building a Database of Online Databases. Bin He, Chengkai Li, David
Killian, Mitesh Patel, Yuping Tseng, and Kevin Chen-Chuan Chang.
UIUCDCS-R-2006-2752, Department of Computer Science, UIUC, July
2006. [PDF]
Structured
Databases on the Web: Observations and Implications.
K. C.-C. Chang, B. He, C. Li, M. Patel, and
Z. Zhang.
SIGMOD Record, 33(3):61-70, September 2004.
[PDF]
Supporting Ranking and Clustering as Generalized Order-By and Group-By.
Chengkai Li, Min Wang, Lipyeow Lim, Haixun Wang, and Kevin Chen-Chuan Chang.
To appear in Proceedings of the 2007 ACM SIGMOD Conference (SIGMOD
2007), Beijing, China, June 2007. (69/480=14%).
[PDF] [Slides PPT]
Supporting Ad-hoc Ranking
Aggregates.
Chengkai Li, Kevin Chen-Chuan Chang, and Ihab F. Ilyas.
In Proceedings of the 2006 ACM SIGMOD Conference (SIGMOD
2006),
pages 61-72, Chicago, Illinois, June 2006. (58/446=13%).
[PDF]
[Slides PPT]
RankSQL: Query Algebra
and Optimization for Relational Top-k Queries.
Chengkai Li, Kevin Chen-Chuan Chang, Ihab F. Ilyas, and Sumin Song.
In Proceedings of the 2005 ACM SIGMOD Conference (SIGMOD
2005),
pages 131-142, Baltimore, Maryland, June 2005. (65/431=15%).
[PDF]
[Slides PPT]
Composing XSL
Transformations with XML Publishing Views.
Chengkai Li, Philip Bohannon, Henry F. Korth, and PPS Narayan.
In Proceedings of the 2003 ACM SIGMOD Conference (SIGMOD
2003),
pages 515-526, San Diego, California, June 2003. (52/342=15%).
[PDF]
[Slides PPT]
Query Routing:
Finding Ways in the Maze of the Deep Web.
Govind Kabra, Chengkai Li, and Kevin Chen-Chuan Chang.
In Proceedings of the ICDE Workshop on Challenges in Web
Information Retrieval and Integration (ICDE-WIRI 2005),
Tokyo, Japan, April 2005. (14/47=30%).
[PDF]
RankSQL: Supporting
Ranking Queries in Relational Database Management Systems.
Chengkai Li, Mohamed Ali, Kevin Chen-Chuan Chang, and Ihab F. Ilyas.
In Proceedings of the 31st International Conference on Very
Large Data Bases (VLDB 2005),
pages 1342-1345, Trondheim, Norway, August 2005. Demonstration
description.
[PDF]
Relational On-Line
Exchange with XML.
Philip Bohannon, Xin (Luna) Dong, Sumit Ganguly, Henry F. Korth,
Chengkai Li, P.P.S. Narayan, and Pradeep Shenoy.
In Proceedings of the 2003 ACM SIGMOD Conference (SIGMOD
2003),
pages 673, San Diego, California, June 2003. Demonstration
description.
[PDF]
Beyond SQL: Structured Data Retrieval by Ranking.[Slides PPT]
Florida State University, Tallahassee, FL, April 2007.
University of Texas at Arlington, Arlington, TX, March 2007.
Purdue University, West Lafayette, IN, November 2006.
Indiana University, Bloomington, IN, November 2006.
Illinois Institute of Technology, Chicago, IL, October 2006.
University of Texas at Arlington, Arlington, TX, September 2006.
Supporting Ranking and Clustering as Generalized Order-By and Group-By.
In the 2007 ACM SIGMOD Conference (SIGMOD
2007), Beijing, China, June 11, 2007.[Slides PPT]
Supporting Ad-hoc
Ranking Aggregates.
In the 2006 ACM SIGMOD Conference (SIGMOD 2006), Chicago, Illinois,
June 27, 2006.
[Slides PPT]
RankSQL: Query
Algebra and Optimization for Relational Top-k Queries.
In the 2005 ACM SIGMOD Conference (SIGMOD 2005), Baltimore, Maryland,
June 14, 2005.
[Slides PPT]
Composing XSL
Transformations with XML Publishing Views.
In the 2003 ACM SIGMOD Conference (SIGMOD 2003), San Diego,
California, June 12, 2003.
[Slides PPT]
Reviewer:
VLDB Journal, IEEE Transactions on Knowledge and Data Engineering (TKDE),
IEEE Transactions on Parallel and Distributed Systems (TPDS), Information
Systems
External reviewer of journals:
ACM Transactions on Database Systems (TODS),
