Recent advancements of fuzzy sets: Theory and practice

This special issue encompasses six papers devoted to the recent advancements in the field of fuzzy sets. The seed of the current issue were some of the presentations made in three special sessions organized by the guest editors at the Nineth International Conference on Information Processing and Management of Uncertainty in Knowledge-based Systems (IPMU 2002) that was held in Annecy, France, July 1–5, 2002. These six original contributions have been thoroughly revised and expanded to become the papers currently presented in this issue. Fuzzy sets were introduced in 1965 by Lofti Zadeh with a view to reconcile mathematical modelling and human knowledge in the engineering sciences. The concept of fuzzy sets is one of the most fundamental and influential tools in the development of the computational intelligence. Fuzzy sets can provide solutions to a broad range of problems of control, pattern classification, reasoning, planning, information retrieval, computer vision, computational linguistics, and so on. This special issue offers recent advancements of the use of fuzzy sets in the development of computational linguistics or processes of computing with words (CW). The concept of CW is based on the concept of linguistic variable defined by Zadeh. CW is a methodology in which words are used in place of numbers to accomplish processes of computing and reasoning. According to Zadeh there are two major imperatives for CW. First, CW is a necessity when the available information is too imprecise to justify the use of precise numbers, and second, when there is a tolerance for imprecision which can be exploited to achieve tractability, robustness, low solution cost, and better rapport with reality.