The Theta-Model for Distributed Real-Time Systems

The Theta-Model is a time free (i.e., message driven) model for distributed systems, which assumes that the end-to-end delays of the fastest and slowest messages simultaneously in transit are correlated.
This page provides a collection of research papers on the Theta-Model.  Here is an introductory presentation, a poster and some advertising stuff.


INRIA Rocquencourt

Vienna University of Technology

 INRIA  tu-en-voll-blau-pos-kl.gif


Gérard Le Lann

Jean-François Hermant

Embedded Computing Systems

Ulrich Schmid
Daniel Albeseder
Martin Hutle (now at EPFL)
Heinrich Moser
Josef Widder


Project duration: 2004-2008   (final project report)

Project leader: Ulrich Schmid

The work at TU Vienna has been supported by the Austrian


under project number P17757; part of the work has been continued in the FWF project PSRTS. Additionally, this project is related to the FIT-IT project DARTS, which employs Theta-algorithms for fault-tolerant clock generation in VLSI systems-on-chip.

Selected Papers

Josef Widder and Ulrich Schmid. The Theta-Model: Achieving synchrony without clocks. Distributed Computing, 22(1):29-47, April 2009.

Martin Hutle, Dahlia Malkhi, Ulrich Schmid, and Lidong Zhou. Chasing the weakest system model for implementing omega and consensus. IEEE Transactions on Dependable and Secure Computing, 6(4):269-281, 2009.

Josef Widder and Ulrich Schmid. Booting clock synchronization in partially synchronous systems with hybrid process and link failures. Distributed Computing, 20(2):115-140, August 2007.

Heinrich Moser and Ulrich Schmid. Optimal clock synchronization revisited: Upper and lower bounds in real-time systems. In Proceedings of the International Conference on Principles of Distributed Systems (OPODIS), LNCS 4305, pages 95-109, Bordeaux & Saint-Emilion, France, Dec 2006. Springer Verlag.

Gérard Le Lann and Ulrich Schmid. How to implement a timer-free perfect failure detector in partially synchronous systems. Technical Report 183/1-127, Department of Automation, Technische Universität Wien, January 2003. (Replaced by Research Report 28/2005, Institut für Technische Informatik, TU Wien, 2005.).

Full list of papers