Database Lab in NTOU
Introduction
Background
The lab is located in Department of
Computer Science, National Taiwan Ocean University, Keelung, Taiwan. It was established
by Associate Professor Ya-hui Chang since 1999, and have master students
graduated since 2002. We encourage our group members to have free mind and
strong motivation to investigate the research problem encountered, and hope to
have real impact on the database field.
Research direction
Heterogeneous database
We develop techniques to produce interoperable queries with object and relational databases. A user poses a local query in a local query language, against a local object or relational schema. We transparently produce appropriate queries with respect to a remote target object or relational schema, corresponding to some remote database which contains data relevant to the user’s query. Mapping knowledge to resolve representational heterogeneities in local and remote schemas is expressed in a canonical representation. A canonical representation is also used to resolve heterogeneities of query languages.
Mobile database
The advance of the mobile computing
environment allows data to be accessed in any place at any time, but currently
only simple and ad-hoc queries are supported. People are eager for mobile
information systems with more functionality and powerful querying facilities.
We design a graphical query language called MoSQL to be the basis of general
mobile information systems. It provides a uniform way for users to access
alphanumerical data and to query current or future location information, based
on an icon-based interface. The interface is particularly suitable for the
mobile environment, since it is easily operated by clicking or dragging the
mouse.
XML database
Providing an efficient way to
support XML query processing has become a very important issue. This field is
currently the main focus of the lab. Specifically, we are working on the
following problems:
encoding XML data
and constructing indexes to provide XQuery processing;
building a wrapper
for XML document so that queries could be efficiently answered;
translating SQL
and XQuery so that RDB and XML documents could share information
Lab director: Ya-Hui Chang
Education
background
·
B.S., Dept of Computer Science and
Information Engineering from National Taiwan University, Taiwan.
· M.S., Dept of Computer Science from University of Maryland at College Park, USA.
·
PhD, Dept of Computer Science from
University of Maryland at College Park, USA.
publication
Journal Papers
1.
Raschid,
L., Chang, Y., “Interoperable Query Processing from Object to Relational
Schemas Based on a Parameterized Canonical Representation”, International
Journal of Cooperative Information systems, Vol. 4, No. 1, 81-120, 1995, World
Scientific Publisher.
2.
Chang,
Y. and Raschid, L., “Producing Interoperable Queries for Relational and
Object-Oriented Databases”, Journal of Intelligent Information Systems, Vol.
14, No. 1, 2000, Kluwer Publisher.
3.
Ya-Hui
Chang, Ben-Hsu Chen, Chun-Chieh Wu, “The Design and Implementation of an
Efficient Library Management System by XML”, Journal of Internet Technology,
volume 2, number 4, 2001.
4. Chang, Y., “A Graphical Query
Language for Mobile Information Systems”, to appear in ACM SIGMOD Record, 2003.
Conference
Papers
1.
Raschid,
L., Chang, Y., and Dorr, B., “Interoperable query processing with multiple
heterogeneous knowledge servers”, Proceedings of the second international
conference on information and knowledge management, 1993.
2.
Raschid,
L., Chang, Y., and Dorr, B., “Query transformation techniques for interoperable
query processing in cooperative information systems”, Proceedings of the second
international conference on cooperative information systems, 1994.
3.
Chang,
Y., Raschid, L., and Dorr, B., “Transforming queries from a relational schema
to an equivalent object schema: a prototype based on F-logic”, Proceedings of
the eighth international symposium on methodologies for intelligent systems,
1994.
4.
Chang,
Y., Raschid, L., “Building Parameterized Canonical Representations to Achieve
Interoperability Among Heterogeneous Databases”, Proceedings of the Sixth
International Hong Kong Computer Society Database Workshop on Database
Reengineering and Interoperability, Hong Kong, March, 1995.
5.
Chang,
Y., “An Algorithm to Extract Semantics from relational Query Languages”, Proceedings
of the Thirteenth Workshop on Combinatorial Mathematics and Computation Theory,
Shalu, Taiwan, R. O. C., June, 1996.
6.
Chang,
Y., Koh, J. And Chen, A. “An Object-Oriented Approach to Modeling and Querying
in Multimedia Information Systems”, Proceedings of the Second Conference on
Multimedia Information Systems, 1997.
7.
Chang,
Y., “A Query Translator to Achieve Interoperability for Relational and
Object-Oriented Databases”, Proceedings of the Conference on Distributed System
Technologies and Applications, 1998.
8. Chang, Y., “A Query Language
for Mobile Information Systems”, Proceedings of IEEE ICDCS workshop on wireless
network and mobile computing, 2000.
9. Ya-Hui
Chang and Tsan-Lung Hsieh, “A document-based approach to indexing XML data”,
Proceedings of the fourth international conference on information integration
and web-based applications & services, 2002.
10.
Ya-Hui Chang and Cheng-Ta Lee, “Supporting
selection-projection XQuery Processing based on encoding paths”, to appear in
the Proceedings of DASFAA, 2003.
Contact information:
email address: yahui@mail.ntou.edu.tw
Last updated: January 1st, 2003