Finite Deterministic DEVS (FDDEVS)  

FDDEVS, finite deterministic DEVS, is a sub-class of DEVS that exploits its finite state description to provide benefits in ease of use and leaning as well as ability to support analysis, verification, and automation. FDDEVS offers an approach to complex system development that is similar to the finite state specification of objects in UML ??with some major differences that include its origins in DEVS from which it inherits mathematical rigor, well-definition, and theoretical foundation. FDDEVS is at just the right level of abstraction where its descriptions are complete enough to map into models capable of simulation in DEVS environments such as DEVSJAVA while serving as skeletons for extension into full-fledged DEVS models. In this way, a GUI for FDDEVS can support easier specification of DEVS models that can be analyzed and verified at the finite state level. At the same time, they can provide the basis for automation in specific application domains.

The properties of FDDEVS are very useful from an educational perspective. It is relatively simple and straightforward to provide an easy introduction to DEVS while still preserving the essential nature of the discrete event dynamic system properties such as events, timings, and model composition. It is amenable to automation in which a natural language model description is transformed into a working DEVS model which can be manipulated in a simulation viewer. Although limited in its expressive power, FDDEVS models can serve as a skeleton from which to develop full-scale DEVS model by elaboration.

FDDEVS enables a gentle introduction to essential DEVS concepts, including:

  • Finite DEVS : Atomic models
    • Ports: input, output
    • States, including starting state
    • Functions: time advance, internal transition, external transition, output
  • Behavior of Finite DEVS
    • Injecting inputs
    • Observing state transitions, outputs
  • Compositions of Finite DEVS
    • Coupled models via automated port-matching coupling
  • Behavior of Coupled Models:
    • Message exchange
    • State trajectory
    • Output trajectory

An in-depth, hands-on, introduction to FDDEVS is provided at the ACIMS Education Page.

FDDEVS supports integrated system development and testing through its facilitation of automated mapping in DEVS models.