RESUMEN
In the last decade, a signed diagram, often
called the Causal Loop Diagram, has become a premodeling technique in the
simulation of socioeconomic systems. This research expresses qualitative and
quantitative properties of this diagram. Two different versions of causal maps
are presented. The first one corresponds to the well-known Causal Loop Diagram,
which depicts the interactions between the changes in the state variables. The
second one has been formalized from individual components encountered in
biological and chemical applications. This second diagram is called the
Detailed Causal Loop Diagram, and it depicts the interactions between the
levels or storages in the systems. The structures of both kinds of diagrams and
the transformation of one into the other are studied. Moreover, mathematical
transformations to represent their properties are introduced.
Qualitative principles of the causal diagrams
relating dynamic properties such as stability, oscillations, controllability,
and observability, are introduced.
Computer simulations of both causal diagrams
are performed. The programs are written in DYNAMO, using two special FORTRAN
functions called CAUSE and CAUSA. Documentation and listing of the computer
programs and functions is provided.