where [PHI] is standard normal distribution function. Provided that the condition of independent normal variables is not satisfied, a series of approximate reliability algorithm are proposed such as the aforementioned FOSM method and SOSM method.

So the Y(u) transform from the uniform distribution to the cumulative standard normal distribution function, Moro algorithm has a high degree of accuracy.

Cumulates and normal distribution function, built on the results of experimental determination of the values of time intervals [t.sub.bI] and [t.sub.bO], corresponding on and off operations of the RT relay with winding rated supply voltage US = 48 V: 1--relay on, voltage of the control circuit (source) [U.sub.C] = 48 V; 2--relay off at [U.sub.C] = 48 V; 3--relay on at [U.sub.C] = 336 V; 4--relay off at [U.sub.C] = 336 V

The most common condition for the random variable [[epsilon].sub.t] is the fact it follows a normal distribution function, except the fact that it represents a white noise, condition that generates a certain formal commonness.

(2003) proposed the following three objective functions: (1) a likelihood distribution based on the t distribution (if the degrees of freedom exhibit small values, then the t distribution results in fatter tails than the normal distribution), (2) the tail size of the normal distribution is increased by adding a constant number in the normal distribution function (the constant is a small fixed value such as 0.01), and (3) a distribution function is used with tails having a suitable size, such as a two-component mixture probability distribution function.

In case the value of the standard normal distribution function is equal to the service level, the stock level q barely covers the expected utilization demand [mu] that can be characterized with an a standard deviation by an SSL reliability level:

To determine the theoretical frequency of variation range of the studied trait was used the normal distribution function I (f (t)), for which the equation of Gauss--Laplace was exposed to following contraction: