Distributed Computing
ETH Zurich

Discrete Event Systems (HS 2017)

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 exploring the limits of what is computable and what is not. In doing so, we will consider three distinct models of computation which are often used to model discrete event systems: finite automata, push-down automata and Turing machines (ranked in terms of expressiveness power). 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 continuous time markov chains and queueing theory for an understanding of the typical behavior of a system. Then we analyze discrete event systems from a worst-case perspective using the theory of online algorithms and adversarial queueing. In the last part of the course we introduce methods that allow to formally verify certain properties of Finite Automata and Petri Nets. These are some typical analysis questions we will look at: Do two given systems behave the same? Does a given system behave as intended? Does the system eventually enter a dangerous state?

Course language: English and German

Lecture by Prof. Lothar Thiele, Prof. Laurent Vanbever, and Prof. Roger Wattenhofer, Thursday 13.15-15.00 @ ETZ E 6, starting 21.09.2017.

Exercises by Sebastian Brandt, Romain Jacob, Xiaoxi He, Ahmed El-Hassany and Maria Apostolaki, Thursday 15.15-16.45 @ ETZ E 6

Exercise Proceedings

At the beginning of every lecture week, we will publish a new exercise sheet here. This exercise sheet is intended to be solved during the exercise session on Thursday where two tutors will be available to assist you and to answer potential questions. The exercises often require information from the lecture notes, so please make sure that you have them available in some way.

You can hand in your solutions for correction after the exercise session on a voluntary basis. But this is not mandatory or required to be admitted to the exam.

Lecture material


Title Lecturer Slides Additional Material References

Chapter 0
Introduction
21/09/2017
Prof. Vanbever PDF 1:1
PDF 4:1
[cassandras]
[sipser]
[exorciser]

Chapter 1
Automata and Languages (Part 1)
21/09/2017
Prof. Vanbever PDF 1:1
PDF 4:1
[sipser]
[exorciser]

Chapter 2
Automata and Languages (Part 2)
27/09/2017
Prof. Vanbever PDF 1:1
PDF 4:1
[sipser]

Chapter 3
Non-regular Languages and Context Free Grammars
05/10/2017
Prof. Vanbever PDF 1:1
PDF 4:1
[sipser]

Chapter 4
Context Free Languages
12/10/2017
Prof. Vanbever PDF 1:1
PDF 4:1
[sipser]

Chapter 5
Push-Down Automatas and Turing Machines
19/10/2017
Prof. Vanbever PDF 1:1
PDF 4:1
[sipser]

Chapter 6
Queueing
26/10/2017
02/11/2017
Prof. Wattenhofer PDF 1:1
PDF 4:1
[bertsekas]
[schickinger]

Chapter 7
Online
02/11/2017
09/11/2017
Prof. Wattenhofer PDF 1:1
PDF 4:1
[borodin]
[fiat]
[hochbaum]

Chapter 8
Verification of Finite Automata
23/11/2017
07/12/2017
Prof. Thiele PDF 1:1
PDF 4:1
[burch]

Chapter
NO LECTURE
30/11/2017
NO LECTURE PDF 1:1
PDF 4:1


Chapter 8
Verification of Finite Automata (continued)
07/12/2017
Prof. Thiele PDF 1:1
PDF 4:1
[burch]

Chapter 9
Petri Nets
14/12/2017
21/12/2017
Prof. Thiele PDF 1:1
PDF 4:1
[murata]


Exercise material


Title Exercise Sample Solution

Exercise 1
21/09/2017
Download Download

Exercise 2
28/09/2017
Download Download

Exercise 3
05/10/2017
Download Download

Exercise 4
19/10/2017
Download Download

Exercise 5
26/10/2017
Download Download

Exercise 6
02/11/2017
Download Download

Exercise 7
09/11/2017
Download Download

Exercise 8
16/11/2017
Download Download

Exercise 9
23/11/2017
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Exercise NO EXERCISE
30/11/2017
Download


References

[bertsekas] Data Networks
Dimitri Bertsekas, Robert Gallager.
Prentice Hall, 1991, ISBN: 0132009161
[borodin] Online Computation and Competitive Analysis
Allan Borodin, Ran El-Yaniv.
Cambridge University Press, 1998
[burch] Symbolic Model Checking
Burch, J. R. and Clarke, E. M. and McMillan, K. L. and Dill, D. L. and Hwang, L. J.
Inf. Comput. 98, 2 (June 1992), pp. 142-170
Download
[cassandras] Introduction to Discrete Event Systems
Christos Cassandras, Stephane Lafortune.
Kluwer Academic Publishers, 1999, ISBN 0-7923-8609-4
[exorciser] Exorciser - Interaktive Lernsoftware für theoretische Informatik
Download
[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
Download
[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