  Modeling and Simulation (M&S) for system design and prototyping is practiced
today both in the industry and academia. M&S are two different areas altogether
and have specific objectives. However, most of the times these two separate
areas are taken together. The developed code is tightly woven around both the
model and the underlying simulator that executes it. This constraints both the
model development and the simulation engine that impacts scalability of the
developed code. Furthermore, a lot of time is spent in development of a model
because it needs both domain knowledge and simulation techniques, which also
requires communication among users and developers. Unified Modeling Language
(UML) is widely accepted in the industry, whereas Discrete Event Specification
(DEVS) based modeling that separates the model and the simulator, provides a
cleaner methodology to develop models and is much used in academia. DEVS today
is used by engineers who understand discrete event modeling at a much detailed
level and are able to translate requirements to DEVS modeling code. There have
been earlier efforts to integrate UML and DEVS but they haven't succeeded in
providing a transformation mechanism due to inherent differences in these two
modeling paradigms. This paper presents an integrated approach towards
crosstransformations between UML and DEVS using the proposed eUDEVS, which
stands for executable UML based on DEVS. Further, we will also show that the
obtained DEVS models belong to a specific class of DEVS models called Finite
Deterministic DEVS (FD-DEVS) that is available as a W3C XML Schema in XFD-DEVS.
We also put the proposed eUDEVS in a much larger unifying framework called DEVS
Unified Process that allows bifurcated model-continuity based lifecycle
methodology for systems M&S. Finally, we demonstrate the laid concepts with a
complete example.
