# solve a fuzzy logic problem

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I have to use fuzzy to find the likelihood of a fire in a car based on the following conditions, The judgment set are as follows: u1—（0.5，0.3，0.1，0.1）Likelihood of a fire occurring while charging a car u2—（0.3，0.2，0.2，0.3）The evaluation set for a car crash fire u3—（ 0 ，0.1，0.4，0.5）The judgment set for a car flooding fire u4—（0.4，0.4，0.1，0.1）The critical set affected and ignited

which means – considering u1 - Likelihood of a fire while charging a car, 50% said it's big, 30% said it was larger, 10% said it was average, 10% said it's small same for u2,u3 and u4

The evaluation set of these four factors is composed of the evaluation matrix：

The fuzzy comprehensive decision-making model of fire risk of new energy vehicles is as follows:

Due to the 0.5＋0.3＋0.2＋0.2＝1.2，In order to find the percentage, the normalization process is performed, namely：

It can be seen from the formula that the comprehensive decision of the four factors affecting the new energy vehicle fire is as follows: 41% people think such accidents are very dangerous, 25% people think relatively dangerous, 17% people think the danger is average, and 17% people think there is no danger.

The above is my question to solve, I have opened fuzzy interface and created 4 inputs Then my doubts are What type of membership function MF type is suitable for this problem, shall i use gaussianmf ? Also have doubt in how to give inputs based on these conditions - like How many MFs (membership functions should i give) What value range shoud i give in params How to set the rules? What is their weight value I should assign? How many outputs should i give, is it one or four I have referred a video on Getting Started with Fuzzy Logic Toolbox, but i'm still not clear to how to solve the problem. I would be of great help if someone could really assist me in solving this?

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### Answers (1)

Sam Chak
on 4 Apr 2022

Take this slowly. First, specify what those 4 inputs to the fuzzy system are, and the outputs of the fuzzy system. (I don't know what symbols you have chosen, so I just use for inputs and for outputs.)

Before determining the type of MF to be used, and the number of MFs, try constructing the structure of the Fuzzy If-Then Rules from your expert opinions:

IF is 𝒜 AND is ℬ AND is 𝒞 AND is 𝒟, THEN is 𝒫 AND is 𝒬 AND is ℛ AND is 𝒮

where

are the input fuzzy sets and are the output fuzzy sets.

##### 4 Comments

Sam Chak
on 5 Apr 2022

Edited: Sam Chak
on 5 Apr 2022

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