CLAVS/ODVS: Combining Class/Object Diagrams and DEVS

The Discrete EVent system Specification (DEVS) formalism is a modular discrete-event modeling formalism. It has a formal specification in terms of systems theory and is supported by several efficient and usable simulator implementations. In these implementations, the DEVS formalism is often "grafted" onto an existing Object-Oriented programming language. Examples are C++ in the case of ADEVS and Python in the case of PythonPDEVS. To match this grafting, we present CLAVS, the CLAss diagram and deVS formalism and its instance counterpart ODVS, the Object Diagram and deVS formalism, and their visual notations. These languages use an automaton-like visual notation for Atomic DEVS models and a Class Diagram notation augmented with port information and event structure specification. An implementation of a visual CLAVS/ODVS modeling environment built on draw.io is presented. The use and usefulness of the formalism is demonstrated by means of a simple traffic model whose detailed specification is presented.