Information Technology Reference
In-Depth Information
supports the development of conceptual models. Additionally it may
guide the development of formal models as well and can therefore be
applied in two phases of a model development process (see Figure 6.9):
While developing a
conceptual model
the GRAMS reference model
acts as a guideline for model developers. It helps to ensure that all
important aspects are thought of and that they are documented
in a uniform way. Thus, the GRAMS reference model helps to
create a better common understanding between the involved model
developers and may prevent misunderstandings. The common un-
derstanding of a model and its documentation enables and improves
reuse of single model components and forms the basis for V&V-
activities.
Similarly, the GRAMS reference model provides a (semi-) formal
description of an agent-based model and its simulation. Just as
providing guidance for developing conceptual models, the GRAMS
reference model provides guidance for developing
formal models
.
The GRAMS reference model does not impose the use of a specific
formalism, but leaves this decision open to the developers.
Ideally, the ideas laid out in the GRAMS reference model are strictly
followed in an implementation. The transformation from a conceptual
or formal model to an executable model could easily be done and
benefits could be fully exploited (e. g., a strict separation of model
and simulation engine allows to execute the same model on different
simulation engines).
The GRAMS reference model is quite abstract on the conceptual
level and is not constrained by any formalization- or implementation-
specific issues. This may be illustrated by an example regarding the
definition of simulation time. Whereas for a specific model, it may
be completely sucient to define simulation time on a conceptual
level as continuous, this specification may be refined during the form-
alization phase to real numbers. Regarding the executable model,
implementation-specific issues have to taken into account (e. g., time
may be discretized and represented as an integer).
