الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
In the context of regular relational databases, functional dependencies(FD) have received a ( lot of attention, since they capture some semantics about the data related to redundancy Informally, a FD is a property valid on a relation, stating that tuples with the same value on a set A of attributes have the same value on a set 13 of attributes. The need to incorporate and treat information given in fuzzy terms in Relational Databases has concentrated a great effort in the last years. A fuzzy extension of this concept has been introduced to overcome the previous anomalous behaviors and study its properties when defining a Fuzzy Functional Dependency, if antecedent values are. very similar then consequent values must he slightly similar.
However, the definition of Fuzzy Functional Dependencies – the more resemblant antecedent values are, the more consequent values must be – forbids to have resemblant antecedent values and distinct consequent values, which is not realistic in practice. Indeed two tall persons might have different weights. There may be some (but very few) tuple values breaking the fuzzy dependency- This is called the problem of the outliers.
In this thesis, we arc concerned with the problem of detecting the outliers, i.e, the exceptional tuple values breaking the fuzzy dependency. Using the typology of fuzzy rules, we distinguish three kinds of Fuzzy Functional Dependency and propose a general framework for extending the definition of Fuzzy Functional Dependency.
According to a semantical view of fuzzy rules for handling exceptions, this framework is based on the graded certainty/possibility of the resemblance of the consequent attributes rathel than the graduality of the resemblance of these attributes. or, primary interest is the exceptionality computation, which is represented by the Fuzzy Certainty Rule Dependency or the Fuzzy Possibility Rule Dependency proposed in the thesis, and which will be taken if consideration by both the designer, and the database user. A combined approach has been proposed to combine both the Fuzzy Certainty Rule Dependency and the Fuzzy Possibility Rule Dependency for a better view of the system