Answers to Multiple Choice Questions

Q1. Which of the following is not true regarding the principles of fuzzy logic ?

Answer: B. Fuzzy logic follows the principle of Aristotle and Buddha.
Explanation: Aristotle and Buddha followed principles which contradicted each other. Aristotle stated that a something is true or not true, whereas Buddha stated that something can be true and also not true to a certain extent. Aristotle followed the concept of bivalence and Buddha followed the concept of multivalence.

Why the others are wrong?

A.Fuzzy logic is a concept of `certain degree'.
Fuzzy logic differs to Boolean logic in a sense that something can be true to a certain extent and does not have to be just true or false.
C.Japan is currently the most active users of fuzzy logic.
When it was founded in the 60s the Americans and the rest of the world totally ignored the idea. Instead, it was adopted by the Japanese followed by Korea and other parts of the East. Currently 70% of Japanese products use fuzzy logic.
D. Boolean logic is a subset of fuzzy logic.
Since Boolean logic only holds for values of 1 or 0 and fuzzy logic holds for a range of values from 1 to 0.

Back to Question 1.

Q2. Where is the minimum criterion used ?

Answer: A. When there is an AND operation .
Explanation: The minimum criterion takes the least value in the set given. In an AND operation all the values have to be true in order for the whole expression to be true. Hence taking the least of the values ensures that the range of all values are met.

Why the others are wrong?

B. When there is an OR operation.
In an OR operation any value in the set can be true in order for the whole operation to be true. In this case the maximum criterion is used
C. In De Morgan's Theorem.
This is clearly wrong as any of the criterions have nothing to do with De Morgan's theorem.
D. None of the above.
Since A has already been justified as correct, this is clearly wrong as well.

Back to Question 2.

Q3. Considering a graphical representation of the `tallness' of people using its appropriate member function, which of the following combibnations are true ?
i. TALL is usually the fuzzy subset.
ii. HEIGHT is usually the fuzzy set.
iii. PEOPLE is usually the universe of discourse.

Answer B. i & iii
When doing a graphical representation of fuzzy subsets, it is important to the definitions clear before the actual drawing.
i. TALL is usually the fuzzy subset.
ii. HEIGHT is usually the actual membership function in which we define.
iii. The variable `people' is usually the universe of discourse because it covers the whole subset.
Hence the answer is i & iii.

Back to Question 3.

Q4. What is the Fuzzy Appoximation Theorem(FAT)?

Answer: A. A fuzzy sytem can model any continous sytem.
Explanation: The Fuzzy Approximation Theorem(FAT) as stated by Bart Kosko shows a fuzzy sytem can model any contionous system. Each of the rules acts as a fuzzy patch that the system places so as to resemble the response of the continous system.

Why the others are wrong

B. The conversion of fuzzy logic to probability.
Fuzzy logic and probability are two completely different concepts and cannot be converted to one another.
C. A continous sytem can model any fuzzy system.
This is vice-versa of the answer and is clearly wrong.
D. Fuzzy patches covering a series of fuzzy rules.
The fuzzy rules are represented by fuzzy patches, and the patches are suppose to be able to cover any curve in a continous system.

Back to Question 4.

Q5. What is the main difference between probability and fuzzy logic

Answer: C. Probability is ADDITIVE, meaning all its values must add up to one.
Eplanation: This is the main difference between fuzzy logic and probability. Although, both probability and fuzzy logic contain values between the ranges 1 and 0, fuzzy logic tells the extent of a specific member function, whereas probability gives the frequency, hence all values of its set must add up to one.

Why the others are wrong.

A. Fuzzy logic is probability in disguise.
This is an assumtion that pro-probability scientists usually make. It is clearly untrue or this question would not be asked. B. Fuzzy logic is the likelihood of an event occuring and probablility is the extent of that event.
Quite the contrary. Probablity is the likelihood of an event occuring and fuzzy logic is the extent of that event occuring.
D. Probability dissipates with decreasing information.
Probability dissipates, in fact with increasing information. This means that the more information we have, the more likely the probability of that event occuring.

Back to Question 5.

Q6

In an adaptive fuzzy system
i. The machine learns as more data are fed into it.
ii. Nueral network is used to find the fuzzy rules.
iii. The system creates rules without the intevention of human beings.

Answer: B. i & ii
Explanation:
i. An adaptive fuzzy machine works using the DIRO(Data In Rules Out) principle. This means that as data is fed into a black box, rules are generated. The black box is a nuearal network and is beyond the scope of the two articles.
ii. As said in i. , nueral networks are used to generate the fuzzy rules, and is beyond thescope of this article.
iii. This is a bit ambigous as we are led to believe that the main concept of an adaptive fuzzy sytem is that machines should be able to think for themselves. However, it is still the user(human being) that feeds in data, hence there still is human intervention.
Hence the answer is B. i & ii

Back to Question 6.

Q7

What are the following sequence of steps taken in designing a fuzzy logic machine?

Answer A:Fuzzification->Rule evaluation->Defuzzification
Explanation: When designing a fuzzy logic, we first have to define the fuzzy sets, and make appropriate member functions. Then rule evaluation comes in which matches the sets to its corresponding rules(a series of if-then statements). More about this can be found in the fuzzy rules section on Shahariz Aziz's second article by clicking
here .
Why other's are wrong?
The other's are simply rearrangements of the correct answer and are obviously wrong.

Back to Question 7.

Q8. Fuzzy logic has rapidly become one of the most successful of today's technologies for developing sophisticated control systems. The reason for this is:
i. Fuzzy logic mimics the human way of thinking.
ii. Fuzzy logic enables the ability to generate precise solutions from certain or approximate information.
iii. Fuzzy logic is easy to implement.
Answer: B. i & ii

Explanation:
i. Fuzzy logic applies the concept of `certain degree' which is similar to the way human beings think. Instead of just being either true or false, fuzzy logic can be true partially and also false partially at the same time. This is similar to the human mind.
ii. Fuzzy logic can uses exact points representing to what degree an event occurs, and with fuzzy rules, generate precise outcomes.
iii. This is not true because a fuzzy machine with just 5 fuzzy rules, take weeks to design and months or even years to simulate and work properly. It is relatively easy to think of, but difficult to implement.
Please refer to Parthiban's first article for a more thorough explanation by clicking
here

Back to Question 8.

Q9

Answer: A
Explanation: Since this is an OR operation, we use the maximum criterion in which the maximum value of the set is taken.
Please click
here to refer to the fuzzy logic operations section in Shahariz Aziz's article#1.

Back to Question 9.

Q10. Who is the founder of fuzzy logic?

Answer: D. Zader Lotfi. Explanation. This is clearly bookwork as there can only be one answer. The only ambiguity that may occur is B. Buddha. This is still false however, because Fuzzy logic was inspired bu Buddha but was only officially found in the 60s including the word `fuzzy' itself.

Back to Question 10.

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