Indexing a Fuzzy Database Using the Technique of Superimposed Coding { Cost Models and Measurements Indexing a Fuzzy Database Using the Technique of Superimposed Coding { Cost Models and Measurements

Recently, new applications have emerged that require database management systems with uncertainty capabilities. Many of the existing approaches to modelling uncertainty in database management systems are based on the theory of fuzzy sets. High performance is a necessary precondition for the acceptance of such systems by end users. However, performance issues have been quite neglected in research on fuzzy database management systems so far. In this article they are addressed explicitly. We propose new index structures for fuzzy database management systems based on the well known technique of superimposed coding together with detailed cost models. The correctness of the cost models as well as the eeciency of the index structures proposed is validated by a number of measurements on experimental fuzzy databases.