Providing efficient query processing in database systems is one step in gaining acceptance of such systems by end users. We propose several techniques for indexing fuzzy sets in databases to improve the query evaluation performance. Three of the presented access methods are based on superimposed coding, while the fourth relies on inverted files. The efficiency of these techniques was evaluated ...

sustainable development is very important especially in environment. in this paper, the value of sustainable development in environment of iran for iron and steel making in comparison with global, determined by fuzzy logic and expressed by continuous value between zero and one. the following steps were taken in turn: 1- obtaining the related data from internal resources. 2- defining membership ...

It is estimated that every 20 months or so the amount of information in the world doubles. In the same way, tools that mine knowledge from data must develop to combat this growth. Such techniques must be able to extract useful, meaningful patterns efficiently in the presence of large amounts of noisy, redundant and sometimes misleading information. To be able to achieve this, data mining is oft...

The use of fuzzy logic for the modeling of processes (such as a technical process or the behavior of a human operator in a process) is often motivated by the interpretability of the resulting fuzzy system/model. In fuzzy models, the dependencies of the variables of the considered process are described by qualitative (linguistic) if–then rules, which correspond to the way in which human knowledg...

This paper deals with closure properties of models of fuzzy attribute implications. Fuzzy attribute implications are particular IF-THEN rules which can be interpreted in data tables with fuzzy attributes and/or ranked data tables over domains with similarity relations. We show that models of any set of fuzzy attribute implications form a fuzzy closure system with hedge. Conversely, we show that...

We present a logic for reasoning with if-then formulas which involve constants for rational truth degrees from the unit interval. We introduce graded semantic and syntactic entailment of formulas. We prove the logic is complete in Pavelka style and depending on the choice of structure of truth degrees, the logic is a decidable fragment of the Rational Pavelka logic (RPL) or the Rational Product...

A fuzzy spatial data mining technique has been developed to extract relationships describing relative position of classes of objects from raster images. Several different rule forms are described which represent different types of directional relationships between classes of objects. The method has been tested with hand-generated, synthetic, and sonar imagery.