Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences

COLLEGE OF ENGINEERING

UC Berkeley

   

2008 Research Summary

Ptolemy Project

View Current Project Information

Edward A. Lee, Hugo Andrade, Christine Avanessians, Christopher Brooks, Dai Bui, Elaine Cheong, Thomas Huining Feng, Shanna-Shaye Forbes, Ben Lickly, Isaac Liu, Thomas Mandl, Eleftherios Matsikoudis, Slobodan Matic, Hwa-yong Oh, Hiren Patel, Mary Stewart, Min Van Ly, Yang Zhao, Gang Zhou and Jia Zou

The Ptolemy Project studies modeling, simulation, and design of concurrent, real-time, embedded systems. The focus is on assembly of concurrent components [1-3]. 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 [4]: 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 [5]: 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;
  • 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]
C. Brooks, E. A. Lee, X. Liu, S. Neuendorffer, Y. Zhao, and H. Zheng (eds.), "Heterogeneous Concurrent Modeling and Design in Java (Volume 1: Introduction to Ptolemy II," UC Berkeley EECS Department Technical Report No. UCB/EECS-2007-7, January 11, 2007.
[2]
C. Brooks, E. A. Lee, X. Liu, S. Neuendorffer, Y. Zhao, and H. Zheng (eds.), "Heterogeneous Concurrent Modeling and Design in Java (Volume 2: Ptolemy II Software Architecture)," UC Berkeley EECS Department Technical Report No. UCB/EECS-2007-8, January 11, 2007.
[3]
C. Brooks, E. A. Lee, X. Liu, S. Neuendorffer, Y. Zhao, and H. Zheng (eds.), "Heterogeneous Concurrent Modeling and Design in Java (Volume 3: Ptolemy II Domains)," UC Berkeley EECS Department Technical Reports, UC Berkeley EECS Department Technical Report No. UCB/EECS-2007-9, January 11, 2007.
[4]
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.
[5]
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.