文档介绍：THESIS ON INFORMATICS AND SYSTEM ENGINEERING
Transparent Fuzzy Systems:
Modeling and Control
Andri Riid
TALLINN TECHNICAL UNIVERSITY
FACULTY OF INFORMATION TECHNOLOGY
DEPARTMENT PUTER CONTROL
Thesis submitted in partial fulfillment of the requirements for the degree
of Doctor of Philosophy in Engineering in Tallinn Technical University
© Andri Riid, 2002
ii
Abstract
During the last twenty years, fuzzy logic has been essfully applied to many
modeling and control problems. One of the reasons of ess is that fuzzy
logic provides human-friendly and understandable knowledge representation
that can be utilized in expert knowledge extraction and implementation. It is
observed, however, that transparency, which is vital for undistorted information
transfer, is not a default property of fuzzy systems, moreover, application of
algorithms that identify fuzzy systems from data will most likely destroy any
semantics a fuzzy system ever had after initialization.
This thesis thoroughly investigates the issues related to transparency. Fuzzy
systems are generally divided into two classes. It is shown here that for these
classes different definitions of transparency apply. For standard fuzzy systems
that use fuzzy propositions in IF-THEN rules, explicit transparency constraints
have been derived. Based on these constraints, exploitation/modification
schemes of existing identification algorithms are suggested, moreover, a new
algorithm for training standard fuzzy systems has been proposed, with a
considerable potential to reduce the gap between accuracy and transparency in
fuzzy modeling. For 1st order Takagi-Sugeno systems that are interpreted in
terms of local linear models, such conditions cannot be derived due to system
architecture and its undesirable interpolation properties of 1st order TS systems.