It is a dynamic tiered process, which is of practical activities, is not a simple binding factor, but binding nature combined with the move is a further stratification strength.
Cleaning, which was once a simple decision among a few cleaning agents and types of equipment, is now recognized as a major factor in process control and product improvement.
The first model is a simple one-factor model in which the logarithm of the spot price of the commodity is assumed to follow o-u process which has a mean reverting character.