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given sex to the amount of subjects of another sex [89, 155, 158] gives new interesting
possibilities of the development and applications of the evolution algorithms.
5.4.4 Examples of the Co-evolution Systems
The co-evolution agent system we consider, consists of an environment and agents.
The environment has the form of a graph consisting of vertices in which the
agents may exist, and edges through which the agents may relocate between the
vertices. The environment is composed of resources and information accessible to
the agents. The agents existing in a given vertex of the graph may contact only those
agents which exist in the same vertex and use the resources which are placed in that
vertex.
The agents existing in the system are divided into groups referred to as species.
Actions characteristic of the agents of a given species are specified. The agents of a
given species may be divided into groups of sexes characterized by actions specific
to a particular sex. A set of relationships is specified for the agents of a given species,
which may occur in relation to agents of other species. There are specific interaction
processes between species (and alternatively between sexes).
The agents existing in the system are realized on the basis of the multi-profile
architecture of the
M
-
agent
.The
reproductive profile
, which includes such strate-
gies as
finding and acceptance
of the partner for
reproduction
, and
migration
,is
responsible for the most important process of the evolution system. There is one
accessible type of the resource in the system whose total amount is constant. Part of
this resource is placed in the environment and the rest is possessed by the agents (the
resource gained by agents). The resources that are possessed by the agents may be
used by the agent for the realization of different actions: the selection and acceptance
of partners for reproduction, migration and the agent's existence itself (“energetic”
resource ensuring “life energy” of the agent).
The origin of species is the result of the emergence of a group of agents isolated
reproductively from other agents (other groups, other species). So, compared with the
EMAS
systems, the
CoEMAS
systems allow for the appearance (and disappearance)
of new species, as well as for interactions between the representatives of particular
species.
The appearance of species may be particularly useful for solving certain tasks
which include searching for the local extrema of the multi-modal functions. The
task of the co-evolution system concentrates here on finding all local extrema
(in practice as large number of extrema as possible) of a given multi-modal
function
f
. A given local extremum is considered as found if there is an appropriate
number of subjects (larger than minimum) in the immediate environment of a given
extremum.
Further, the results of the operation of the system applied to the search for the
local extrema of the multi-modal function
f
R
referred to as the Rastrigin function were
presented [77]. This task involves finding all (or at least as large number as possible)
