Ptolemy II is the third generation of software produced within the Ptolemy project [Hylands et al., 2003; Ptolemy Project, 2004] at the University of California at Berkeley. Ptolemy II supports heterogeneous, hierarchical modeling, simulation, and design of concurrent systems, especially embedded systems. The focus is on complex systems mixing various technologies and operations. Simulation models are constructed under models of computation that govern the interaction of the components in the model. Different models of computation are used for modeling different types of systems. The abstraction provided by the model of computation also simplifies code generation from the Ptolemy models.
Ptolemy is component-based and models are constructed by connecting a set of components and have them interact under the model of computation. Components in Ptolemy are called actors. An important feature of Ptolemy is its focus on heterogeneous, hierarchical modeling, meaning that each system may be composed of a number of subsystems at different
levels where each subsystem can have its own model of computation. This makes it easier to deal with complexity. Ptolemy is Java-based and provides graphical user interfaces for model construction and result visualization.
More information on Ptolemy II (p.51)
Ptolemy II website