A study of equivalence in uncertain deductive databases:
When does classical equivalence coincide with
equivalence under uncertainty?
Project Success and Impact
This project is funded under RUI program,
Research in Undergraduate Institutions.
Currently, we have an undergraduate program in Computer Science,
offering a B.S. degree (recently accredited by CSAB).
Our proposal to establish an M.S. degree in Computer Science
is in its last step of (final) approval,
and we are looking forward to starting our MS in Computer Science
in Fall 1998.
The following undergraduate students have worked with me on research
in the past three years:
(1) Mr. Jonathan Blakely (now a masters student at Duke University),
(2) Mr. Bryan Marsh (now with Intelligent Information Systems; he is
planning to attend the University of North Carolina at Chapel Hill
for graduate studies),
(3) Mr. Stephen Slocum (now a masters student at NC State University),
and
(4) Ms. Salley Wilson (now with IBM Global Services).
I also supervised a Masters (in Mathematics).
Mr. Patrick Shouse defended his thesis in April 97.
He was with US Airways, and
has recently joined the Aon Consulting services.
I will present a tutorial on
"Uncertainty Management in Database and Knowledge-base Systems",
jointly with Dr. V. S. Lakshmanan,
at the 1998 IEEE International Conference on Data Engineering,
February 23-27, 1998, Orlando, Florida.
Project References
(Please refer to
http://www.uncg.edu/~sadrif/papers.html
for a more complete listing.)
V. S. Lakshmanan, and F. Sadri,
``On A Theory of Probabilistic Deductive Databases.''
October 1997. Submitted to JLP.
V. S. Lakshmanan, and F. Sadri,
``Uncertain Deductive Databases: A Hybrid Approach,''
Information Systems,
Vol. 22, No. 8, pp 483-508, December 1997.
V. S. Alagar, F. Sadri, and J. N. Said,
``Semantics of an Extended Relational Model for Managing
Uncertain Information.''
Proceedings of Fourth International Conference on Information
and Knowledge Management, 1995, (CIKM'95), pp 234-240.
F. Sadri,
``Information Source Tracking Method: Efficiency Issues.''
IEEE Transactions on Knowledge and Data Engineering,
Vol. 7, No. 6, December 1995, pp 947-954.
F. Sadri,
``Integrity Constraints in the
Information Source Tracking Method.''
IEEE Transactions on Knowledge and Data Engineering,
Vol. 7, No. 1, February 1995, pp 106-119.
Area Background
Approaches to the modeling and management of uncertainty and
inaccuracy in database and knowledge-base systems can be categorized into
two broad categories, quantitative and qualitative.
Quantitative techniques use numerical factors for uncertainty,
and manipulate these factors to obtain numerical measures for
the uncertainty of derived data.
Numerous methods based on various mathematical concepts,
such as probability theory, fuzzy sets and fuzzy logic, and
Dempster Shafer theory of evidence have been developed so far.
Qualitative techniques are often based on partitioning the data into
``definite'' and ``indefinite'' components, and extend the classical
query processing techniques to manipulate these components.
Disjunctive logic programming and disjunctive databases are also
examples of qualitative approaches to the modeling of uncertainty.
We advocate a hybrid approach: In the
Information Source Tracking (IST) method,
the certainty of data is modeled by the reliability of
the sources of data. The system keeps track of the association
between data and sources, and computes this information for
derived data (such as answers to queries). Then, if desired,
a numerical factor of certainty can be calculated for derived
data as a function of the reliabilities of the contributing sources,
and their nature of contribution. This two-phase approach
makes it also possible to use different paradigms, such as
probability theory and fuzzy sets theory, for the numeric
phase while maintaining the non-numeric phase intact.
Area References
A recent survey has appeared in
Zaniolo et al,
Advanced Database Systems,
Morgan Kaufmann, 1997
(Part V: Uncertainty in Databases and Knowledge Bases).
We recently gave a tutorial at the 14th IEEE International Conference
on Data Engineering, Orlando, Fl., February 23-27, 1998:
V. S. Lakshmanan and F. Sadri,
"Uncertainty Management in Database and Knowledge-Base Systems."
Slides are available from
http://www.uncg.edu/~sadrif/papers/icde98tute.ps.
Our works on Information Source Tracking and Probabilistic Deductive
Databases are listed in
http://www.uncg.edu/~sadrif/papers.html.
Some papers are available on-line.
A bibliography of recent publications on
uncertainty in database and knowledge-base systems
is available from
http://www.uncg.edu/~sadrif/papers/uncer-biblio.ps.
Potential Related Projects
Relationship / applications of ideas from this project to
integration of information from multiple sources merit
further investigation.
This page was last modified on March 24, 98