Fuzzy Logic example that's simple?

Question

I'm rather crap at maths, and while I rather liked the basic programming in pascal lessons I was taught in high school I'm fairly crap at programming also. I'm also kind of a nerd though however and I try to understand things I think are interesting as best I can despite my deficits in appropriate skills.

I tried to look up fuzzy logic on wikipedia and while it was pretty detailed, I'd like to know an example of how it works and in the example an explanation why traditional binary logic would not work. They give an example on the page but it was a little tricky for me to understand - it looked rather a lot like traditional binary logic to me except devoid of an 'else' function. I guess it's the mathematics that set the example a little above my understanding. Anyone think they can have a crack at another more simplified example and explanation of why it's useful in opposition to binary logic?

http://en.wikipedia.org/wiki/Fuzzy_logic

Answer 1

Trader Logic:



When the stock price is $14.67 buy 100000 shares at $14.67



Very precise.



Trader Fuzzy Logic



When the momentum in the market sector "feels" right on a busy day buy 100000 shares in several lots around $14.67



How experts actually do things.

Answer 2

Fuzzy logic involves variables who's values are not precise. A very good example is given in the website itself:



IF temperature IS very cold THEN stop fan

IF temperature IS cold THEN turn down fan

IF temperature IS normal THEN maintain level

IF temperature IS hot THEN speed up fan



Here, words such as 'cold', 'very cold', 'normal' and 'hot' have been used. But what exactly do these mean? What is cold to a person living in the tropics may be hot to a person living in Greenland. So, the value ranges of the variables are not well defined.



Fuzzy logic cannot be used to program computers. If you feed this program into a computer, it will not know what to do because computers don't know what 'cold' or 'hot' mean. You need to give it a definite range of values to operate in, such as:



IF temperature < 15 THEN stop fan

IF 15 < temperature < 20 THEN turn down fan

IF 20< temperature < 25 THEN maintain level

IF temperature >25 THEN speed up fan



Fuzzy logic programming is integral to the development of artificial intelligence. If we can 'tell' a computer what 'hot' or 'cold' is, we can let it do the 'thinking' during a situation and act accordingly.



Hope this helps.

Answer 3

Te main difference between fuzzy logic and binary logic is that in binary logic we can predict 100% outcome of an event with true(1) or false(0).

For example take the tossing of a coin,its either head or tails.if we assign head as true(1) and tail has false(0).



In Fuzzy logic,for example the tallness of a person has to be decided we cannot apply binary logic and hence we go for a range of truth values assigned to them like

4.3 inch 5.0 inch --> short where 4.3 inch may be 20% true,5.0 may be 100% true 4.5 be 40% true

5.1inch 5.7 inch-->medium.

5.8 and above-->tall.

Coming to the wikipedia example



IF temperature IS very cold THEN stop fan(for example 8 C to -4 C)

IF temperature IS cold THEN turn down fan(-3 C to 20 C

IF temperature IS normal THEN maintain level(21 C to 32 C)

IF temperature IS hot THEN speed up fan(33 C and above)



NOT x = (1 - truth(x)) means that if x->0.6 true then NOT (x)->1 - 0.6:=0.4(40%).



x AND y = minimum(truth(x), truth(y)means that if the truth of x is 0.4 and y is 0.6 then x AND y gives 0.4.



x OR y = maximum(truth(x), truth(y)) similarly for x OR y it is 0.6



hope this helped you in some way.

Answer 4

Fuzzy logic is taken under consideration one of those multi-valued logic derived from fuzzy set thought to handle reasoning it quite is approximate particularly than precise. the furry logic variables would have a club fee of no longer in basic terms 0 or a million. in simple terms as in fuzzy set thought with fuzzy logic the set club values can variety (inclusively) between 0 and a million, in fuzzy logic the degree of certainty of a fact can variety between 0 and a million and isn't any longer limited to the two certainty values {real (a million), fake (0)} as in classic propositional logic.

Answer 5

Logic: A + B = C



Fuzzy logic: A + B = C +/- 1



With pure logic a machine might have to register (detect) an exact quantity (C) to actuate, whereas with fuzzy logic the machine would actuate if C is 'close enough' for practical purposes. Some machines using artificial intelligence can use fuzzy logic and can 'learn' what is close enough.