Fuzzy set

From Biocrawler, the free encyclopedia.

Fuzzy sets are an extension of the classical set theory used in fuzzy logic. A fuzzy set is characterized by a membership function, which maps the members of the universe into the unit interval [0,1]. The value 0 means that the member is not included in the given set, 1 describes a fully included member (this behaviour corresponds to the indicator function of classical sets). The values between 0 and 1 characterize fuzzy members.

For the universe X and given the membership-degree function f : X→[0,1], the fuzzy set A is defined as A = {(x, f(x)) | x ∈ X}.

The fuzzy set B, where B = {(3,0.3), (4,0.7), (5,1), (6,0.4)} would be enumerated as B = {0.3/3, 0.7/4, 1/5, 0.4/6} using standard fuzzy notation. Note that any value with a membership grade of zero does not appear in the expression of the set. The standard notation for finding the membership grade of the fuzzy set B at 6 is μB(6) = 0.4.

See also

• Defuzzification
• Fuzzy logic
• fuzzy set operations
• Rough set

External links

Fuzzy Image Processing (http://pami.uwaterloo.ca/tizhoosh/set.htm)

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Wikipedia (http://en.wikipedia.org/wiki/Main_Page) Fuzzy_set (http://en.wikipedia.org/wiki/Fuzzy_set) version history (http://en.wikipedia.org/w/index.php?title=Fuzzy_set&action=history) GNU Free Documentation Lizenz (http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License) CC-by-sa (http://creativecommons.org/licenses/by-sa/2.5/)

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