p.3 Models are central to our understanding of the real world because they enable us to represent and manipulate
real phenomena, then explore the results.
p.3-4 We develop models to better understand the impact of alternative decisions on... performance,
resource use... Models are essential tools in generating new knowledge. They help us simplify
complex phenomena by eliminating everything we believe is extraneous to what we want to study... With the right models
we can explore... dynamic as well as static phenomena. through such knowledge, we can explain the world around us and, possibly,
anticipate future happenings.
p.4 Real-world phenomena can be difficult to study... Models, as abstractions of reality, force
us to consider the results of our structural and dynamic assumptions... After you narrow down the details to those
that describe the problem, you must specify the relationships among them. The relevant details (the variables) and their relationships
establish your model.
p.6 Dynamic models are those that try to reflect changes in real or simulated time and take into account
that the model components are constantly evolving as a result of previous actions... The world is not a static or
comparative static process, and so the models treating it in that way will become obsolete and perhaps even misleading.
p.6 Through computer modeling we can study processes in the real world by sketching simplified versions
of the forces assumed to underlie them.
p.7 Models study cause and effect; they are causal. The modeler specifies initial conditions
and relations among these elements. The model then describes how each condition will change in response to changes in other
conditions.
p.20 identify what you hope to achieve in modeling the system. Ask yourself if the problem is descriptive
or predictive. 2. Define your state variables
p.24 The predictive ability of models is further reduced by the possibility of the occurrence of previously
unencountered constraints on, and development possibilities for, the systems.
