System dynamics is one approach to model and simulate the
dynamics of complex operational systems such as population,
ecological and economic systems, which usually interact strongly
with each other. In the system dynamical approach, the purpose
is to build model that imitates the real feedback structure of
the system and captures the characteristic behavior of a system,
such as, oscillation, information delays, and stability. The
basic building blocks, stocks and flows, are used to describe
the system feedback loops which create the nonlinearity found so
frequently in every day problems. Operational systems containing
both high hierarchy entities, such as, budget cuts or company
culture and lower hierarchy entities, such as, production
inventories and supply lines are difficult to analyze and design
– the scope, dynamics, nonlinearities, time dependencies and
complexity limit the available theoretical tools. In many cases
modeling and simulation are the only viable tools that can be
used to analyze the behav