Inventory based system, proposed theoretically by Takahashi
(2003), is an alternative for competitive environments with
unstable changes in demand. The inventory level is monitored
to detect unstable fluctuations. Every time instability is detected,
the number of signals in a unity is increased or decreased,
differently from the other systems in which the additional signals
number is also defined a priori. This is another system that
considers the important issue of changing the number of signals
to adapt the kanban system.