environment design (defined in a particular
formalism).
After introducing the required background
information, the proposed model-driven scenario
development process is presented. Then the process
is illustrated with a simple example.
2 BACKGROUND
The definition of scenario has long been a subject of
discussion. Siegfried et al. (Siegfried et al., 2012)
define a scenario as a specification of conditions and
situations to be represented by a simulation
environment for its purpose.
In IEEE 1278 (IEEE, 1993), the standard for
Distributed Interactive Simulation, a scenario is
defined as the description of initial conditions and
timeline of significant events. The definition given
in the High Level Architecture Glossary (US
Department of Defense, 1996) stresses that a
scenario shall identify the major entities with their
capabilities, behavior and interactions over time with
all related environmental conditions. The NATO
Science and Technology Organization Modeling and
Simulation Group 053 (MSG-053, 2010) defines a
scenario as a description of the hypothetical or real
area, environment, means, objectives and events
during a specified time frame related to events of
interest.
The operational scenarios are provided in the
early stages of a simulation environment
development process by the user or the sponsor. The
operational scenarios can be documented in any
textual or graphical form. The key elements in a
scenario are the initial state, the desired end state,
the course of actions to reach the prescribed end
state, and the entities with their capabilities and
relations.
The operational scenarios provide a coarse
description of the intended situation and its
dynamics, but they need to be refined and
augmented with additional information pertaining to
simulation. This refinement is usually done by M&S
experts and results in conceptual scenarios.
Conceptual scenarios provide a detailed
specification of the piece of the world to be
represented in the simulation environment and
should provide crucial information for everyone who
is involved in the later stages of the simulation
environment engineering process.
Once a simulation environment is designed and
set up, the executable scenarios have to be available
for all simulation systems and other member
applications of the simulation environment. For this
purpose, the conceptual scenarios need to be
transformed into executable scenarios. An
executable scenario is the specification of a specific
situation providing all information necessary for the
preparation, initialization, and execution of a
simulation environment and for supporting scenario
management activities such as scenario distribution
and role casting (Topçu & Oğuztüzün, 2010). The
transformation from conceptual scenarios to
executable scenarios is undertaken primarily by the
operator of the member applications of the
simulation environment (possibly assisted by M&S
experts or subject matter experts). Ideally, the
resulting executable scenarios are specified in a way
that they are directly processable by the member
applications (e.g. as a file containing parameters or
via a web service).
3 DEVELOPMENT PROCESS
A standard perspective for the utilisation of
scenarios in simulation development and execution
is introduced in IEEE Recommended Practice for
Distributed Simulation Engineering and Execution
Process (DSEEP) (IEEE, 2010a). DSEEP describes
a process framework for development and execution
of distributed simulation environments. The DSEEP
recommends scenario development activity as a part
of the problem conceptual analysis. The outcome of
this activity is defined as the major entities that must
be represented in the simulation environment,
description of their capabilities, behaviors and
relationships, event timelines, the environment, and
the initial and terminal conditions. The DSEEP then
prescribes the utilization of scenarios: a) for the
design of a simulation environment and for the
design of the member applications, and b) for
designing and establishing the simulation
environment agreements in simulation environment
development. These agreements enable the
simulation applications to interoperate. From an
HLA perspective, this corresponds to defining
federates, a Federation Object Model (IEEE, 2010b),
and Federation Agreements (Johns Hopkins
University Applied Physics Laboratory, 2010).
MDE has also been employed in systems
development in the simulation domain to generate
elements of a simulation system or simulation
environment from models via model transformations
(Topçu et al., 2008) (Adak et al., 2009) (Gaševic et
al., 2009) (Durak et al., 2009) (Tolk, 2002)
(Cetinkaya et al., 2011). The MDE methodology is
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