How are the lower and upper bound values of the moths determined in the Moth-Flame Optimization algorithm?

I am currently implementing the Moth-Flame Optimization (MFO) Algorithm, based on the paper: Moth-Flame Optimization Algorithm: A Novel Nature-inspired Heuristic Paradigm.

To calculate the values of the Moths, it uses two arrays of values, which contain upper and lower values for each variable. However, as far as I can see. it mentions nothing about what these values are. Quoting from the paper:

As can be seen, there are two other arrays called $$ub$$ and $$lb$$. These matrixes define the upper and lower bounds of the variables as follows:

$$ub = [ub_1, ub_2, ub_3, \dots,ub_{n-1}, ub_n]$$

where $$ub_i$$ indicates the upper bound of the $$i$$-th variable.

$$lb = [lb_1, lb_2, lb_3, \dots, ub_{n-1}, ub_n]$$

where $$lb_i$$ indicates the lower bound of the $$i$$-th variable