Time and Space Compression
Simulation is a discipline for developing a level of understanding
of the interaction of the parts of a system, and of the system
as a whole. The level of understanding which may be developed
via this discipline is seldom achievable via any other discipline.
After some consideration regarding a meaningful way to put
System, Model, and Simulation in an appropriate perspective I
arrived at the following distinction.
A system is an entity which maintains its existence through
the mutual interaction of its parts. A system exists and operates
in time and space.
A model is a simplified representation of a system over some
time period or spatial extent intended to promote understanding
of the real system.
A simulation is the manipulation of a model in such a way
that it operates on time and/or space to compress it, thus enabling
one to perceive the interactions that would otherwise not be
apparent because of their separation in time or space. This compression
also provides a perspective on what happens within the system,
which, because of the complexity of the system, would probably
otherwise not be evident.
Types of Simulation
There are essentially two types of simulation, continuous and
discrete. And, to say there is somewhat of a controversy over
these two would be more than just an understatement. A controversy
which I understand, and don't understand, at the same time. It
seems like both camps want to be "right" and the rest
of the world should learn to sing their tune. Bah humbug!
They're both right, in a way, yet it seems they refuse to have
the lenses in their glasses fixed. As Ben Kuipers said in "Qualitative
Reasoning," "In most ways, and at most times, the world
changes continuously." With considerations for Einstein's
Theory of Relativity this seems to make sense. So what's the difficulty?
The difficulty lies in being disconnected from our own thoughts
and actions. It's very much akin to the difference between "Espoused
Theories" and "Theories in Use" as defined by Chris
Consider a rather mundane example, like filling a bathtub with
water. I can turn on the faucet and fill the tub with a continuous
stream of water, or I can fill it with buckets of water. Either
way the tub gets full, yet one method would be viewed as continuous
filling and the other as discrete. The operative word here is
"viewed." Whether things are continuous or discrete
is a matter of perception on the part of the observer over the
time frame of the observation. This is very similar to the way
electrons seem to act as particles or waves depending on the manner
in which one chooses to look at them.
Discrete Simulation * Continuous Simulation
theWay of Systems
Copyright © 2004 Gene Bellinger