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sets (version 0.1-1)

fuzzy: Fuzzy logic

Description

Fuzzy Logic

Usage

fuzzy_logic(new, ...)
.N.(x)
.T.(x, y)
.S.(x, y)
.I.(x, y)

Arguments

x, y
Numeric vectors.
new
A character string specifying one of the available fuzzy logic families (see details).
...
optional parameters for the selected family.

encoding

UTF-8

Details

A call to fuzzy_logic() without arguments returns the currently set fuzzy logic, i.e., a named list with four components N, T, S, and I containing the corresponding functions for negation, conjunction ($t$-norm), disjunction ($t$-conorm), and implication (which may not be available).

The package provides several fuzzy logic families. A concrete fuzzy logic is selected by calling fuzzy_logic with a character string specifying the family name, and optional parameters. Let us refer to $N(x) = 1 - x$ as the standard negation, and, for a $t$-norm $T$, let $S(x, y) = 1 - T(1 - x, 1 - y)$ by the dual (or complementary) $t$-conorm. Available specifications and corresponding families are as follows, with the standard negation used unless stated otherwise. [object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

The following parametric families are obtained by combining the corresponding families of $t$-norms with the standard negation.

[object Object],[object Object],[object Object],[object Object],[object Object]

By default, the Zadeh family is used.

.N., .T., .S., and .I. are dynamic functions, i.e., wrappers that call the corresponding function of the current fuzzy logic family. Thus, the behavior of code using these functions will change according to the chosen family.

References

C. Alsina, M. J. Frank and B. Schweizer (2006), Associative Functions: Triangular Norms and Copulas. World Scientific. ISBN 981-256-671-6. J. Dombi (1982), A general class of fuzzy operators, the De Morgan class of fuzzy operators and fuzziness measures induced by fuzzy operators, Fuzzy Sets and Systems 8, 149--163.

J. Fodor and M. Roubens (1994), Fuzzy Preference Modelling and Multicriteria Decision Support. Kluwer Academic Publishers, Dordrecht.

B. Schweizer and A. Sklar (1983), Probabilistic Metric Spaces. North-Holland, New York. ISBN 0-444-00666-4.

Examples

Run this code
x <- c(0.7, 0.8)
y <- c(0.2, 0.3)

## Use default family ("Zadeh")
.N.(x)
.T.(x, y)
.S.(x, y)
.I.(x, y)

## Switch family and try again
fuzzy_logic("Fodor")
.N.(x)
.T.(x, y)
.S.(x, y)
.I.(x, y)

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