Information Technology Reference
In-Depth Information
Behavioral and algorithmic complexity (intricate behavior and in-
teraction patterns of system components)
Temporal complexity (time- and state-dependent behavior of system
components)
A key property of complex systems is that no single component
controls the system behavior. Instead, the system behavior results
from multiple and manifold interactions between the components.
The term
emergence
refers to the fact that the system's overall beha-
vior is not obviously derivable from the behavior of its constituting
components. Interactions between the components have to be taken
into account as well as effects of non-linearity [63].
2.1.2 Model
For this thesis a definition of a model is adopted which is not restricted
to a specific domain:
Definition 1 (Model)
A
model
is an idealized, simplifying and with
respect to certain aspects similar representation of an item, system or
some other part of the world. The purpose of the model is to allow a
better study of specific properties than using the original system [54,
p. 103].
In other words, a model is a goal-oriented description of a system
that abstracts some parts of the original system with the intention
to provide an easier explanation or analysis of the original system
(cp. [16, p. 12]). Figure 1.1 illustrates this relation between the original
system (i.e., the system under investigation) and the model as an
idealized and simplified representation of that system. Depending on
the purpose very different types of models are suitable to represent
the original system. Once a model is developed, it may be explored or
analyzed using different techniques, ranging from purely mathematical
solutions to computer simulations. Depending on the chosen technique
to solve a model, more specific terms are common, e.g.,
simulation
model
for a model which is solved by using simulation techniques.
