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relation to the other is defined as the close location when the distance in the domain
of the function is shorter than a certain established breakpoint, and there is no mutual
isolation of the agents. The mutual isolation of two agents takes place when in the
section joining the points being the locations of these agents there are points for
which the value of the adaptation function
f
R
is lower than in the points of agents'
location (when the search for the local extrema gives the local maxima, and higher
when the search gives the local minima).
The following interactions take place between the agents and the niches:
At the level of agents that are subjects which may be included in the niches. At
the moment of creation of the system, the agent has its individual niche where it
is only “inhabitant”. Agents may make decisions, join the niches and be included
in them. Hence, two agents may join their niches and still exist in one common
niche. Inside the niche, the agents are governed by the evolution operations such
as crossing and mutation, as well as rivalry for access to the resource in the niche.
At the level of the relationship agent-niche, the agents may join the existing niches
and leave them. The agent joins the niche when the location of the agent towards
the niche is close, and the agent is not isolated from the agent of the niche. If the
location of the agent towards the location of the niche is that the agent is isolated
from the niche, then the agent leaves a given niche.
At the level of niches (aggregators), the niches are capable of relocating in the
environment. It is realized by the change of the location of the niche as the centre
of gravity of the agents belonging to the niche. If the location of two niches is
close enough, and there is no mutual isolation, then the unification of niches into
one niche may take place. Niches take part in the rivalry for access to the resource
existing in the environment. The resource obtained by the niches is made accessible
by a given niche to the agents of a given species (belonging to a given niche) which
take part in the rivalry for this resource within the niche.
The agents belonging to a given niche create species corresponding to the niche.
In effect, the dynamic system of niches is created in which changing generative
isolation takes place (i.e. making it difficult or even impossible for some agents to
take part in reproduction) allowing for the development of species. On the other
hand, the interactions between the niches result in the fact that they constitute a new
entity “at a more advanced (higher) level”. The above-mentioned interactions are
schematically presented in Fig.
5.22
.
EMAS
System constitutes a system in which the evolution of agents was used
by using basic evolution operations: crossing and mutations, as well as operations
characteristic of the agent, i.e. operations of migrations. In this system there are no
mechanisms allowing for the origin of species.
The simulation research of the systems described above were carried out [77]
on the basis of the agent systems constructed according to the above-mentioned
rules with the use of the architecture of the multi-profile M-agent. Individual profiles
realize appropriate groups of behaviours of the agent (we may consider here: a
resource profile, a reproductive profile, an interaction profile as well as a migration
profile).
