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From: ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University)
Newsgroups: comp.ai
Subject: What is "fuzzy logic"?
Message-ID: <1991Mar28.192533.3272@waikato.ac.nz>
Date: 28 Mar 91 19:25:32 +1200
Organization: University of Waikato, Hamilton, New Zealand
Lines: 34

This is a novice question. I've read precisely one article on
"fuzzy logic" so far that was at all informative, and the
understanding I got from it goes like this:

* Traditional feedback systems are analog in implementation. Their
control signals can be characterized as analytic functions of their
present and past error inputs (e g the classic example of the
engine governor). Sophisticated control algorithms require more
complex analytic functions, which rapidly become unmanageable
in an analog-only implementation.

* With computers, it becomes possible to have control outputs
which are arbitrary combinatorial functions of present and
past error inputs.

* "Fuzzy logic" lies somewhere between a purely analytic and
an arbitrarily combinatorial form; control functions are now
_piecewise analytic_ (a hybrid digital/analog approach). A
combinatorial decision procedure selects a different analytic
function, depending on the ranges of the error inputs. The
resulting compound function is continuous across the decision
boundaries.

Does this agree with what other people understand by "fuzzy logic"?
If so, there isn't really anything in it that can be described
as "fuzzy". Please correct me if I'm wrong.

Lawrence D'Oliveiro                       fone: +64-71-562-889
Computer Services Dept                     fax: +64-71-384-066
University of Waikato            electric mail: ldo@waikato.ac.nz
Hamilton, New Zealand    37^ 47' 26" S, 175^ 19' 7" E, GMT+12:00
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