Research Projects

Ptolemy Project

Edward A. Lee, Ilge Akkaya, Hugo Andrade1, Christopher Brooks, Fabio Cremona, Patricia Derler, Shuhei Emoto2, John Eidson, Barb Hoversten, Hokeun Kim, Akihito Iwai3, Elizabeth Latronico, Gil Lederman, Hendrik Lohstroh, Marco Marazza, Eleftherios Matsikoudis, Tomi Raty4, Christopher Shaver, Mary Stewart, Stavros Tripakis, Armin Wasicek and Michael Zimmer

Center for Hybrid and Embedded Software Systems, National Science Foundation 0931843 (ActionWebs), Naval Research Laboratory N0013-12-1-G015, Robert Bosch GmBH, National Instruments, Denso, Toyota and TerraSwarm, a Semiconductor Research Corporation center, sponsored by MARCO and DARPA.

The Ptolemy Project studies modeling, simulation, and design of concurrent, real-time, embedded systems. The focus is on assembly of concurrent components [1,4]. The key underlying principle in the project is the use of well-defined models of computation that govern the interaction between components. A major problem area being addressed is the use of heterogeneous mixtures of models of computation. Current research thrusts include:

  • Precision-timed (PRET) machines [2]: This effort reintroduces timing into the core abstractions of computing, beginning with instruction set architectures, using configurable hardware as an experimental platform;
  • Real-time software: Models of computation with time and concurrency, metaprogramming techniques, code generation and optimization, domain-specific languages, schedulability analysis, programming of sensor networks;
  • Distributed computing [3]: Models of computation based on distributed discrete events, backtracking techniques, lifecycle management, unreliable networks, modeling of sensor networks;
  • Understandable concurrency: This effort focuses on models of concurrency in software that are more understandable and analyzable than the prevailing abstractions based on threads, and more suitable for implementation on multicore architectures;
  • Systems of systems: This effort focuses on modeling and design of large scale systems, those that include networking, database, grid computing, and information subsystems;
  • Abstract semantics: Domain polymorphism, behavioral type systems, meta-modeling of semantics, comparative models of computation; and
  • Hybrid systems: Blended continuous and discrete dynamics, models of time, operational semantics, and language design.

Figure 1
Figure 1: The Ptolemy project is named after Claudius Ptolemaeus, the second century Greek astronomer, mathematician, and geographer.

[1]
Johan Eker, Jörn W. Janneck, Edward A. Lee, Jie Liu, Xiaojun Liu, Jozsef Ludvig, Stephen Neuendorffer, Sonia Sachs, Yuhong Xiong, " Taming Heterogeneity - the Ptolemy Approach," Proceedings of the IEEE, Jan 2003, Volume: 91, Issue: 1, p127-144.
[2]
S. Edwards and E. A. Lee, " The Case for the Precision Timed (PRET) Machine," UC Berkeley EECS Department Technical Report No. UCB/EECS-2006-149, November 17, 2006.
[3]
Y. Zhao, J. Liu, and E. A. Lee, " A Programming Model for Time-Synchronized Distributed Real-Time Systems," Proceedings of the 13th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS 07), Bellevue, WA, April 3-6, 2007.
[4]
Claudius Ptolemaeus, Editor, System Design, Modeling, and Simulation Using Ptolemy II, Ptolemy.org, 2014.

1National Instruments
2IHI
3Denso
4VTT Technical Research Centre of Finland

More information: http://ptolemy.eecs.berkeley.edu