randomly generate node sensor data(matlab)

[pakitos]

Hi there,
I have x nodes which read temperature

I want to randomly make sensors be either

1) faulty (random wrong reading) <normal or >normal
2) normal reading
3) fire detection reading

but want the probability of 2 higher than the other condition

how to do that?
thanks in advance

 

[zorro]

Hi pakitos,

use rand() function. It returns random numbers uniformly distributed between 0 and 1.
Let x=rand(1);
The probability that x is between 0 and p is p (p between 0 and 1);
The probability that x is between p1 and p2 is p2-p1 (p1, p2 between 0 and 1; p2>p1); ...etc...
Regards

Z

 

[pakitos]

Hi, thanks for the reply
I am using the (rand(1,noNodes)>=0.8) formula
that generates 0 and 1 with the prob I have chosen.
I want if zero to generate randomly specific abnormal values if 1 random normal values

then another case if fire detection happens generate other set of data

my prob how to update data
thanks

 

[zorro]

It is not completely clear for me what do you mean by "randomly specific abnormal values", "random normal values", and " another case", but I guess you want something like this:
Suppose the probabilities of the different cases are P1 and P2 (and P3=1-P1-P2).

x = rand(1,noNodes);
faulty = (x<P1);
normal = ((x>=P1) & (x<P1+P2));
fire = (x>=P1+P2);
reading(faulty) = .............. random values with some distribution
reading(normal) = .............. random values with another distribution
reading(fire) = ............ other values


There are other ways (perhaps more clear if you are not familiar with Matlab) to have the same result, but ths is rather compact.
Regards

Z