A Process Based on the Model-Driven Architecture to Enable the Definition of Platform-Independent Simulation Models - Simulation and Modeling Methodologies, Technologies and Application - page 113

models can be defined through a hierarchical visual editor and represented by XML
documents [38] which are exploited for the generation of PSMs and related code.
Starting from the AMF proposal, the PIM metamodel of the MDA4ABMS process
(see Figure 3) has been effortlessly defined. This metamodel is centered on the con-
cept of (Simulation) Context ( SContext ) which represents an abstract environment in
which (Simulation) Agents ( SAgents ) can act. An SAgent is provided with an internal
state consisting of a set of SAttributes , a visualization style SStyle , and a group of
AActs ( AGroup ) which constitute its behavior. An AAct is characterized by an Execu-
tion Setting which establishes when its execution can start, its periodicity and its
priority.
SContexts , which are themselves SAgents , can be organized hierarchically and con-
tain sub-SContexts . SAgents in an SContext can be organized by using SProjections
which are structures designed to define and enforce relationships among SAgents in
the SContext . In particular, a SNetwork projection defines the relationships of both
acquaintance and influence between SAgents whereas SGrid, SSpace, SGeography
and SValueLayer projections define either the physical space or logical structures in
which the agents can be situated.

SPr oje c tion SContext SAgent AGroup AAct

Execution Setting

0..*

1 1

0. .* 1..*

0..*

1 1

0.. *

SSt yle SA tt ribute

1 AI nizialize ARule ASchedule APerform

SGrid SNe twork SSpace SGeography SValueLayer

Fig. 3. The PIM metamodel

3.3 From CIM to PIM

With reference to an MDA-based process, a target model can be obtained by trans-
forming a source model (M1 Layer in Figure 1) on the basis of the mapping between
the source and target metamodels (M2 Layer in Figure 1). To this end, to enable the
definition of instances of concepts of the target metamodel from instances of concepts
of the source metamodel, mapping rules among the corresponding concepts along
with additional guidelines should be provided [24, 32].
This section, which deals with the mapping between the CIM and PIM metamodels
(see Section 3.1 and 3.2) of the MDA4ABMS process, provides the mapping rules
(Section 3.3.2) and some guidelines (Section 3.3.3) enabling to transform the CIM
entities into PIM entities by taking into account specific aspects (see Section 3.3.1) of
the AMF-based PIM metamodel. The subsequent generation of several PSMs (and
code for the related ABMS platforms) from the obtained PIM can be then easily car-
ried out by the visual and Eclipse-based modelling environment provided by the AMF
framework [3].