In the Simpop framework the agents are
geographical entities : towns and cities
The level of formalization is then different from most applications
of MAS in social sciences. This choice refers to evolutionary urban
theory : the hypothesis is that the dynamics of a town or a city depends
on its ability to interact with other towns and cities, which in turn
depends on its relative situation in the settlement system (in terms of
hierarchical level, specialization, accessibility). The city is then
seen as a coherent entity, whose potential of growth depends first on
its external interactions (core rules of the model) and second on
internal specificities (governance). The interurban interactions are
the driving forces shaping the emergence and evolution of the system of
cities.
Description of the city-agent
- the agents have three main categories of abilities :
to produce, to consume and to exchange. The evolution of a city
(decline, stagnation or growth) is a consequence of its
ability to succeed in these activities, given the
environment and the economico-historical context. The
effects of different kind of perturbations can be
studied;
- the agents are autonomous : they handle and
apply locally a set of rules referring to these
activities and to their consequences in matter of
evolution;
- the agents have knowledge about their
environment : they got information on production and
demand of the cities with which they are interacting;
- the agents have the ability to exchange information,
goods and wealth. The core of the model is built around
two steps : the constitution of the different networks
within which the city will exchange; the formalization
of the exchanges themselves.
Attributes
Each city-agent is characterized by several attributes :
- Localization on a Map
- Population (reevaluated at the end of each iteration)
- Wealth (reevaluated at the end of each iteration)
- Functions port-folio (see below)
- Supply and demand (amount per function, reevaluated at the end
of each
iteration)
The type and level of function can evolve through time, depending on the ability of
the city to adopt innovations and to become attractive for some dynamic and leading activities.
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