Artificial intelligence and Expert system
Soft Computing MethodsJ.A. Johnson
Dept. of Math and Computer Science Seminar SeriesFebruary 8, 2013
OutlineFuzzy Sets
Neural Nets Rough Sets
Bayesian Nets
Genetic AlgorithmsFuzzy sets
Fuzzy set theory is a means of specifying how well an object satisfies a vague description.
A fuzzy set can be defined as a set with fuzzy boundaries
Fuzzy sets were first introduced by Zadeh (1965).
First, the membership function must be determined.How do we represent a fuzzy set in a computer?
ExampleConsider the proposition "Nate is tall."
Is the proposition true if Nate is 5' 10"?
The linguistic term "tall" does not refer to a sharp demarcation of objects into two classesthere are degrees of tallness. Fuzzy set theory treats Tall as a fuzzy predicate and says that the truth value of Tall(Nate) is a number between 0 and 1, rather than being either true or false.
Let A denote the fuzzy set of all tall employees and x be a member of the universe X of all employees. What would the function A(x) look like
A(x) = 1 if x is definitely tall
A(x) = 0 if x is definitely not tall
0