Information Technology Reference
In-Depth Information
Definition 5 (Agent)
An
agent
is an entity that is
situated
in some
environment
, and that is capable of
autonomous action
in this envir-
onment in order to meet its
objectives
.
This definition is very close to [148, p. 29] and conforms with the
definitions given in [60, p. 280], [59,p.83],[46], [61, 112]and[68]. In
good accordance with this definition, the following characteristics of
agents are generally agreed on [108, 83, 61, 112]:
Agents are identifiable, discrete (and usually heterogeneous) indi-
viduals [93, p. 214].
Agents are space-aware, i.e., they are situated in some kind of
environment [83, 23, 120].
Agents are capable of autonomous action and independent decisions.
In this sense, agents are actively acting rather than purely passive
objects [148, p. 28ff.], [93, p. 214], [68].
In order to act within the environment and pursue their goals, agents
are capable of perceiving their environment and acting within this
environment [68], [148, p. 32].
Besides these generally agreed characteristics, many more definitions
(partially very specific to certain domains) exist. Also, many more
characteristics for describing an agent are available. Of these, at least
one characteristic is worth mentioning. The
ability to learn
is part of
many definitions of an agent and refers to the capability of an agent
to adapt (and possibly improve) its behavior [93, p. 214]. The aspect
of agents showing some kind of adaptive behavior or learning is not
part of the definition of an agent used within this thesis. This is due
to the fact that this requirement can not be applied to all kinds of
agents (albeit to a huge number) and therefore is to restraining.
Definition 6 (Agent-based model)
An
agent-based model
is a
simulation model that employs the idea of multiple agents situated
and acting in a common environment as central modeling paradigm.
