Ptolemy ‡ is an open-source and extensible modelling and simulation framework. It offers heterogeneous modeling capabilities by allowing different models of computation, both untimed and timed, to be composed hierarchically in an arbitrary fashion. This paper proposes a formal semantics for Ptolemy that is modular in the sense that atomic actors and their compositions are treated in a unified w...

The Discrete Time (DT) domain in Ptolemy II is a timed extension of the Synchronous Dataflow (SDF) domain. Although not completely backward compatible with SDF, DT keeps most of the desirable properties of SDF like static scheduling, regular/periodic execution, bounded memory usage, and a guarantee that deadlock will never occur. In addition, DT has some desirable temporal properties such as un...

Synchronous Dataflow (SDF) is useful in modeling communications and signal processing systems. We describe a communication actor library based on the SDF semantics in Ptolemy II and show how to use these actors to simulate communication systems. However, many communication and signal processing systems nowadays use adaptive algorithms and control protocols. These sometimes violate SDF principle...

Ptolemy II [2] supports the modeling of heterogeneous systems by using a hierarchical component-based architecture and well-defined models of computation. The basic component in Ptolemy II is called an actor. Actors have por t s , which are their communication interface to other actors. An aggregation of actors and their connections is called a comp o s i t e ac tor . A composi te actor can hav...

Simulating computer architecture as a cyber-physical system has many potential use cases including simulation of side channels and software-in-the-loop modeling and simulation. This paper presents an integrated simulation tool using a computer architecture simulator, gem5 and Ptolemy II. As a case study of this tool, we build a power and thermal model for a DRAM using the proposed tool integrat...

We consider the Ptolemy cluster algebras, which are cluster algebras of finite type A (with non-trivial coefficients) that have been described by Fomin and Zelevinsky using triangulations of a regular polygon. Given any seed Σ in a Ptolemy cluster algebra, we present a formula for the expansion of an arbitrary cluster variable in terms of the cluster variables of the seed Σ. Our formula is give...

The problem addressed by this paper is that real-time embedded software today is commonly built using programming abstractions with little or no temporal semantics. The paper discusses the use of an extension to the Ptolemy II framework as a coordination language for the design of distributed real-time embedded systems. Specifically, the paper shows how to use modal models in the context of the...

tics. For example, the co-design finite state machines We implement a finite state machine (FSM) domain for specifying and simulating control functionality of a system within the Ptolemy software environment. The FSM domain is successfully integrated with synchronous dataflow (SDF) and discrete-event (DE) concurrency domains in Ptolemy. In this heterogeneous combination, the semantics of FSM, c...

A model of computation (MoC) is a formal abstraction of execution in a computer. There is a need for composing diverse MoCs in e-science. Kepler, which is based on Ptolemy II, is a scientific workflow environment that allows for MoC composition. This paper explains how MoCs are combined in Kepler and Ptolemy II and analyzes which combinations of MoCs are currently possible and useful. It demons...