Information Technology Reference
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well as the ability to distinguish data based on inaccurate observation and
measurement.
Rough set was widely studied by computer scientists and mathematicians
since the 1980s and has grown more and more mature in its theory. Its successful
application in the area of knowledge discovery during the later 1980s and early
1990s brought pervasive international attention to this subject. Compared to other
theoretical tools handling uncertainty and fuzziness, rough set theory has many
unique desirable features. In recent years, it has been successfully applied to
information system analysis, artificial intelligence and application, decision
support system, knowledge and data discovery, pattern recognization and
classification, and fault diagnosis, etc.
In some extent, the concept of rough set is similar to many other
mathematical tools that aim to handle vague and inaccurate problems, especially
the evidence theory proposed by Dempster-Shafer (Shafer1976). The major
difference between them is that the main tool used by Dempster-Shafer's theory
is credibility function whereas rough set uses upper approximate and lower
approximate sets as its main tool. Another relationship exists between rough set
theory and fuzzy set theory. Rough set theory is related to fuzzy set theory in
many aspects, and it tries not to compete with the later but to supplement it. In
general, for incomplete knowledge, rough set theory and fuzzy set theory are two
independent methodologies. Moreover, there're also relations between rough set
theory and discriminant analysis, Boolean inference method and decision
analysis.
One of the major advantages of rough set theory is that it does not require any
preliminary or additional information about the data such as: probability
distribution in statistic, basic probability assignment in Dempster-Shafer theory
or membership/probability in fuzzy set theory.
In the 1980s, intensive study on the rough set theory is done by Polish
scholars, including extensive analysis on the mathematical characteristics of
rough set theory and its logic systems. Most of these findings are published on
“Bulletin of The Polish Academic of Science: Mathematics” and “Bulletin of The
Polish Academic of Science: Technical Science”. Application systems were also
developed by them.
Professor Z. Pawlak published the first monograph on rough set theory in
1991, and R. Slowinski chief-edited the symposium on applications and
comparative studies on rough set in 1992. More and more researchers began to
study the applications and theoretical research on rough set theory. The first
