2.3.1. System dynamics in manufacturing
System dynamics modelling deals with the question of how
a system reacts to dynamic forces and how those reactions
shape its behavior during a specific time frame [20]. Stocks
and flows are the fundamental parts of a system dynamics
model. Stocks, which can be seen as state variables are altered
by flows, which are also called rates. The dynamic behavior is
simulated by calculus and differential equations. The
coherence between stocks and flows can by explained easily
with a bathtub example. The water in the tub represents the
stock. It is filled by the inflow from the water tap and drained
by the outflow, if someone puts out the plug [21]. This
coherence is described mathematically with equation 1.