Saturday 4 July 2015

Fuzzy Logic


Fuzzy Logic

11)      It is a form of multivalued logic derived from set theory to deal with reasoning that is approximate rather than premise.

22)      It is a form of mathematical logic in which truth can assume a values in between 0 and 1.

33)      It can be implemented in hardware, software or a combination of both.

44)      It is a superset of conventional or Boolean logic that has been extended to handle the concept of partial truth values between complement true and completely false.

55)      In a fuzzy logic, everything is a matter of degree.

66)      Any logic system can be fuzzified.

77)      In fuzzy logic, knowledge is interpreted as a collection of fuzzy constraint on a collection of variables.

Fuzzy Set

 A fuzzy set A in U where U={u1,u2,u3,......, up to n times} be the universe of discourse, is defined as the set of ordered pairs

A={ (u1.µA(u) : u belongs to U) },

where µA(u) is grade of membership of element u in the set.

The greater µA(u), the greater is the truth of statement that the element u belongs to the set.

The membership function for fuzzy system sets can take values from the closed interval [0,1]

Fuzzy logic is a convenient way to map an input space to an output space. Mapping input to output is starting point for everything.

 

Diagram:

 A black box contains any number of things fuzzy systems, linear systems, expert systems, neural networks, etc.

Why use Fuzzy Logic:

1) conceptually easy to understand

2) flexible

3) can model non linear functions.

4) can be built on top of experienced of exports.

5) based on natural language

6) can control non linear systems.

Components of Fuzzy Systems: