Distributed Computing
ETH Zurich

Discrete Event Systems (HS 2008)

Over the past few decades the rapid evolution of computing, communication, and information technologies has brought about the proliferation of new dynamic systems. A significant part of activity in these systems is governed by operational rules designed by humans. The dynamics of these systems are characterized by asynchronous occurrences of discrete events, some controlled (e.g. hitting a keyboard key, sending a message), some not (e.g. spontaneous failure, packet loss).

The mathematical arsenal centered around differential equations that has been employed in systems engineering to model and study processes governed by the laws of nature is often inadequate or inappropriate for discrete event systems. The challenge is to develop new modeling frameworks, analysis techniques, design tools, testing methods, and optimization processes for this new generation of systems.

In this lecture we give an introduction to discrete event systems. We start out the course by studying popular models of discrete event systems, such as automata and Petri nets. In the second part of the course we analyze discrete event systems. We first examine discrete event systems from an average-case perspective: we model discrete events as stochastic processes, and then apply Markov chains and queuing theory for an understanding of the typical behavior of a system. In the last part of the course we analyze discrete event systems from a worst-case perspective using the theory of online algorithms and adversarial queuing.

Course language: German

Lecture by Prof. Roger Wattenhofer and Dr. Kai Lampka Thursday 13.15-15.00 @ ETF E1.

Exercises by Raphael Eidenbenz and Roland Flury Thursday 15.15-17.00 @ ETF E1.

Exam Review

To look at your exam, please go to our secretary Monica Fricker during the following office hours:
Monday: 15-17
Wednesday: 9-11

Her office is ETZ G88.


The exam is scheduled for Tuesday, 20. January 2009, from 9:00 to 12:00 at HG E5.
You may use any material except communication devices and computers. Please bring your hand-held calculator.

In order to get a feeling of our exam style, you may have a look at this sample exam and the sample solutions.

As some contents of Chapter 3 is new to this lecture, you will not find any questions on some topics (Model Checking, BDDs) in the sample exam. For that matter, you might find this repetition exercises and their sample solutions helpful.

Question Session

We will hold a question session in which we (try to) answer your questions about this lecture. The session is on Tuesday, 13. January 2009, 14:00 - 15:00 at ETZ F78.1
Please send us your questions ahead of time, at the latest until Monday, 12. January 2009 at 14:00 by email to either of the assistants.

Question Wiki

We try to keep all answered questions (not the ones we answer in the question session, though) publicly available on this Question Wiki such that everyone can profit.

Lecture Notes

The following documents are lecture notes from former students. (We provide no guarantee that these documents are correct!)
HS_05 HS_06 HS_07

Lecture material

Title Slides Additional Material References

Chapter 0
PDF 1:1
PDF 4:1

Chapter 1
Automata and Languages
PDF 1:1
PDF 4:1

Chapter 2
Smarter Automata
PDF 1:1
PDF 4:1

Chapter 3a
Specification Models - Intro
PDF 1:1
PDF 4:1
Hinweise zu SDL

Chapter 3b
Specification Models - SDL and MSC
PDF 1:1
PDF 4:1

Chapter 3c
Specification Models - Petri Nets and BDDs
PDF 1:1
PDF 4:1

Chapter 3d
Specification Models - Model Checking and Timed Automata
PDF 1:1
PDF 4:1
Equivalence rules for LTL

Chapter 4
Stochastic Discrete Event Systems
PDF 1:1
PDF 4:1

Chapter 5
Worst Case Event Systems
PDF 1:1
PDF 4:1
Mario und Luigi

Chapter 6
Network Calculus
PDF 1:1
PDF 4:1

Exercise material

Title Exercise Sample Solution

Exercise 1
Assigned: 18/09/2008
Due: 25/9/2008
Download Download

Exercise 2
Assigned: 25/9/2008
Due: 2/10/2008
Download Download

Exercise 3
Assigned: 2/10/2008
Due: 9/10/2008
Download Download

Exercise 4
Assigned: 9/10/2008
Due: 16/10/2008
Download Download

Exercise 5
Assigned: 16/10/2008
Due: 23/10/2008
Download Download

Exercise 6
Assigned: 23/10/2008
Due: 30/10/2008
Download Download

Exercise 7
Assigned: 30/10/2008
Due: 6/11/2008
Download Download Sample solutions updated on 31.10. 15:30 to version 2
Solution for questions 5 and 6

Exercise 8
Assigned: 6/11/2008
Due: 13/11/2008
Download Download Material for Question 3 and 4

Exercise 9
Assigned: 13/11/2008
Due: 20/11/2008
Download Download

Exercise 10
Assigned: 20/11/2008
Due: 27/11/2008
Download Download

Exercise 11
Assigned: 27/11/2008
Due: 4/12/2008
Download Download

Exercise 12
Assigned: 4/12/2008
Due: 11/12/2008
Download Download

Exercise 13
Assigned: 11/12/2008
Due: 18/12/2008
Download Download Notes

Exercise 14
Assigned: 18/12/2008
Due: 24/12/2008
Download Download

Exercise 15
Assigned: 24/12/2008
Due: 24/12/2008
Download Download This is the repetition series to Lampka's part


You do not need a Testat to attend the final exam. However, if you need a Testat, e.g. because you don't intend to take the final exam, but need an attestation that you attended the class, you need to hand in at least 80% of the exercises.


[exorciser] Exorciser - Interaktive Lernsoftware für theoretische Informatik
[bertsekas] Data Networks
Dimitri Bersekas, Robert Gallager
Prentice Hall, 1991, ISBN: 0132009161
[borodin] Online Computation and Competitive Analysis
Allan Borodin, Ran El-Yaniv.
Cambridge University Press, 1998
[boudec] Network Calculus
J.-Y. Le Boudec, P. Thiran
Springer, 2001
[cassandras] Introduction to Discrete Event Systems
Christos Cassandras,Stéphane Lafortune.
Kluwer Academic Publishers, 1999, ISBN 0-7923-8609-4
[fiat] Online Algorithms: The State of the Art
A. Fiat and G. Woeginger
[hochbaum] Approximation Algorithms for NP-hard Problems (Chapter 13 by S. Irani, A. Karlin)
D. Hochbaum
[murata] Petri Nets: Properties, Analysis and Applications
Tadao Murata
Proceedings of the IEEE, vol. 99, issue 4, April 1989. pp. 541--580
[schickinger] Diskrete Strukturen (Band 2: Wahrscheinlichkeitstheorie und Statistik)
T. Schickinger, A. Steger
Springer, Berlin, 2001
[sipser] Introduction to the Theory of Computation
Michael Sipser.
PWS Publishing Company, 1996, ISBN 053494728X
[time] TIMe Electronic Textbook version 4.0 September 1999.
Tutorial on SDL
Tutorial on MSC-96
[doldi] Validation of communications systems with SDL :
the art of SDL simulation and reachability analysis, Chichester Wiley, 2003.
[clarke] Model Checking
Clarke, Grumberg, Peled
MIT Press
[baier] Principles of Model Checking
Christel Baier and Joost-Pieter Katoen
MIT Press
[biere] Symbolic Model Checking without BDDs
Armin Biere, Alessandro Cimatti, Edmund M. Clarke and Yunshan Zhu
TACAS 1999, S. 193-207
[uppaal] Tutorial on Uppaal
Gerd Behrmann, Alexandre David, and Kim G. Larsen
Proceedings of the 4th International School on Formal Methods for the Design of Computer, Communication, and Software Systems (SFM-RT 04). LNCS 3185.