Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!decwrl!ads.com!rlee From: rlee@ADS.COM (Richard Lee) Newsgroups: comp.ai Subject: Re: What is "fuzzy logic"? Message-ID: <74W&JP$@ads.com> Date: 3 Apr 91 18:49:39 GMT References: > Sender: usenet@ads.com (USENET News) Organization: Advanced Decision Systems, Mtn. View, CA Lines: 27 In article kadie@herodotus.cs.uiuc.edu (Carl M. Kadie) writes: |In mikeb@wdl35.wdl.loral.com (Michael H Bender) writes: | |>It is my understanding that in Dr.Zadeh's originial work he DID |>specify various combination functions (e.g., how AND and OR would |>operate.) However, his specifications seemed to be arbitrary and did |>not stand up well to the force of criticism. | |Are these new combination functions less arbitrary? | |(Alternatively, do they show that any choice of combination function |is arbitrary?) I strongly recommend reading "Foundations of Fuzzy Reasoning" by B.R. Gaines (Int'l Journal of Man-Machine Studies #8, 1976, pp 623-668). This paper provides an interesting introduction to fuzzy logic and fuzzy set theory. More to the point, it also has a lengthy discussion of the constraints one might want to impose on a fuzzy logic -- e.g. reducibility to classical logic, associativity, and certain intuitive properties -- and how various choices of functions for And, Or, Not, Implies, etc. meet those constraints. It is worth noting that what constitutes the "right" choice of functions may depend on what the logic is to be used for. The cognitive psychologist Greg Oden has written a number of papers which claim that different choices are appropriate for modelling human cognitive processing on different types of tasks.