Fuzzy models present a singular Janus-face: On the one hand, they are
knowledge-based software environments constructed from a collection of
linguistic IF-THEN rules, and on the other hand, they realize nonline
ar mappings which have interesting mathematical properties like ''low-
order interpolation'' and ''universal function approximation''. Neuro-
fuzzy basically provides fuzzy models with the capacity, based on the
available data, to compensate for the missing human knowledge by an au
tomatic self-tuning of the structure and the parameters. A first conse
quence of this hybridization between the architectural and representat
ional aspect of fuzzy models and the learning mechanisms of neural net
works has been to progressively increase and fuzzify the contrast betw
een the two Janus faces: readability or performance. (C) 1997 Elsevier
Science B.V.