IEEE CONTROL SYSTEMS SOCIETY TECHNICAL COMMITTEE
ON DISCRETE EVENT SYSTEMS

    Ryan J. Leduc
    Chair, IEEE CSS Technical Committee on DES
    Dept. of Computing and Software
    McMaster University
    1280 Main Street West
    Hamilton, Ontario
    Canada L8S 4K1

    Phone: (905) 525-9140 Ext. 27962
    Fax: (905) 524-0340
    e-mail: leduc@mcmaster.ca
    WWW: http://www.cas.mcmaster.ca/~leduc/

DESTC Web Page: http://www.cas.mcmaster.ca/destc/

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Contents:

1. Editorial


2. Conferences
 2.1 2009 American Control Conference, St. Louis, Missouri, USA, June 10
     - 12, 2009
 2.2 IFAC Safeprocess Symposium, Barcelona, Spain, June 30 - July 3,
     2009
 2.3 2nd IFAC Workshop on Dependable Control of Discrete Systems, Bari,
     Italy, June 10 - 12, 2009
 2.4 17th IEEE Mediterranean Conference on Control and Automation,
     MAKEDONIA PALACE HOTEL, THESSALONIKI, GR, June 24 - 26, 2009

3. Journals
 3.1 Selections from IEEE Transactions on Automatic Control, Volume: 53,
      Issue: 4, May 2008
 3.2 Selections from Control Engineering Practice,  Volume 16, Issue 9,
     September 2008
 3.3 Discrete Event Dynamic Systems, Volume 18 Number 3, September 2008
 3.4 Selections from IEEE Transactions on Software Engineering, Volume:
     34, Issue: 3, May 2008

Welcome to the newsletter of the IEEE Control Systems Technical Committee on Discrete Event Systems!

See http://www.cas.mcmaster.ca/destc/ for information on the DESTC.

Personal note from the editor:

Welcome to the June  2008 edition of the DESTC newsletter.

It was great to see many of you again at the WODES'08 in Sweden.  My
compliments to all involved in organizing a wonderful workshop!

Ryan

Contributed by: Larry Holloway <holloway@engr.uky.edu>

2009 AMERICAN CONTROL CONFERENCE
St. Louis, Missouri, USA
June 10 - 12, 2009

Call for Papers --  2009 American Control Conference
June 10-12, 2009
Hyatt Regency St. Louis Riverfront, St. Louis, Missouri, USA 

Submissions are invited for the the 2009 American Control Conference
(ACC), the annual conference of the American Automatic Control 
Council, the U.S. national member organization of the International 
Federation for Automatic Control. The 2009 ACC technical program will 
cover new developments related to theory, application, and education 
in control science and engineering. In addition to regular technical 
sessions the program will also feature interactive and tutorial 
sessions and preconference workshops. 

Submissions are invited in the following categories: Contributed 
papers (long or short), Invited Sessions, Education/Tutorial 
sessions, Preconference workshop proposals, and Exhibit proposals.  
More information is available on the website 
www.a2c2.org/conferences/acc2009 .  Submissions are due September 15, 
2008.

web site: click here

Contributed by: Ryan Leduc <leduc aT mcmaster dOt ca>

IFAC SAFEPROCESS SYMPOSIUM
Barcelona, Spain
June 30 - July 3, 2009

Sponsored by
The IFAC Technical Committee on Fault Detection, Supervision and Safety
of Technical Processes

Co-Sponsored by the IFAC Technical Committees on Modelling,
Identification and Signal Processing; Mechatronics Systems; Chemical
Process Control; Mining, Mineral and Metal Processing; Power Plants 
and Power Systems; Automotive Control; Aerospace; Intelligent 
Autonomous Vehicles.

INTERNATIONAL PROGRAM COMMITTEE
Gertler J. Chair
Patton R. Co-Chair
Isaksson A, Industrial Vice-Chair

Asano K., Biswas G., Blanke M., Ding S., Dixon R., Dodd T., Edelmayer
A., Gentil S., Gustafsson F., Hangos K., Isermann R., Jin J., Kinnaert M.,
Korbicz J., Koscielny J., Lunze J., Malik O., Nikoukhah R., Qin S-Z.,
Ribeiro I., Rizzoni G., Sauter D., Staroswiecki M., Varga A., Wu E., Ye H.,
Zhou D.

NATIONAL ORGANIZING COMMITTEE
Quevedo J. Chair and co-editor
Peran, J.R. Vice-Chair from Industry
Escobet T., facilities director and co-editor
Puig V., logistics and support director and co-editor
Quesada, A., administrative director
Morcego B., web and software support director

Nejjari F., Figueras J., Contreras J., Ginesta R., Sarrate R., Tornil
S., Comasolivas R., Cuguero M.A., Marquez A., Melendez J., Armengol J.,
Pulido B., Vehi J.

TOPICS

Model-based methods: observers, parity relations and identification
Linear, nonlinear and robust methods
Statistical and PCA-based methods
Discrete event and hybrid systems
Computational intelligence in fault diagnosis
Design for reliability and safety
Fault tolerant systems design
Networked systems
Health & condition monitoring of machines and structures
Industrial applications and case studies
Aeronautics and aerospace
Electrical, mechanical and mechatronic systems
Chemical and biomedical processes
Marine systems
Power systems
Robotics
Transportation, traffic and automotive systems

PAPER SUBMISSION
Authors are invited to submit full draft papers (6 pages, two columns)
electronically, by October 31, 2008. Detailed formatting instructions,
and a link to the paper submission site, are found at the symposium web-site.
The submission site will open on September 1, and will close at midnight
(GMT), October 31.

Invited session proposals should be sent to the IPC chair, by September
30, at jgertler@gmu.edu. The proposal should include the title of the session,
name, affiliation and address of the organizer, and a list of invited
authors. Upon receipt of the proposal, a session identification number will be
assigned. Authors of the invited sessions must also submit their full draft
papers by the October 31 deadline, specifying the invited session to which they
belong. Decision on the acceptance of the session will be made on the basis of
the availability and quality of its papers.

SYMPOSIUM MATERIAL AND PUBLICATIONS
Symposium participants will receive the following materials:
- a CD-ROM containing the full text of all accepted papers,
- a printed volume containing the full text of the plenary papers and a
  one-page summary of all regular papers.

The full text of all papers presented at the symposium will be
published, after the symposium, on the IFAC Papers Online website. The best
papers will be recommended for publication in the various IFAC journals

BEST CASE STUDY AWARD
The electrical and automation company ABB will sponsor an award for
the best industrial application/case study paper.

VENUE
The Symposium will be held in Barcelona, Catalonia, Spain, at Sants
Hotel near the central train station and close to the center of Barcelona.

IMPORTANT DATES
October 31, 2008: Electronic submission of full draft papers (6 pages)
February 28, 2009: Notification of draft paper acceptance
March 31, 2009: Final manuscript (full paper + one-page summary) due
June 30, July 1, 2, 3, 2009: SAFEPROCESS 2009 Symposium.

SYMPOSIUM FEES
Standard fee is 360 Euros (225 Euros for full-time students) for
registration before 20th of April 2009. The standard fee includes symposium
attendance, welcome event, preprints (CD + summary volume) and coffee breaks.

Full fee is 450 Euros for registration before 20th of April 2009. The
full fee includes confernce attendance, welcome event, preprints, coffee breaks,
fast lunches, city tour and banquet.

ACCOMMODATION
A block of rooms has been reserved at Sants Hotel for the symposium
participants and accompanying persons. Room rates: Single (Breakfast
included) 135 euros, double (Breakfast included) 150 euros. Restaurant lunch 32
euros. Hotel web site: www.barcelo.com

INFORMATION
Prof. Joseba Quevedo (joseba.quevedo@upc.edu)

web site: click here

Contributed by: Ryan Leduc <leduc aT mcmaster dOt ca>

2ND IFAC WORKSHOP ON DEPENDABLE CONTROL OF DISCRETE SYSTEMS
Bari, Italy
June 10 - 12, 2009

First Announcement and call for papers.

Aims and Scope:

The aim of the workshop is to provide the communities of
safety/reliability analysis and of DES (Discrete Event
Systems) with an opportunity to exchange information
and new ideas, and to discuss new developments in the
field of dependable control of DES. Researches in this
field are driven by the needs of many different application
domains, such as production systems, transport systems,
embedded systems, computers and communication
systems, to name a few.

Several research results recently issued by the two
communities are able to bring partial solutions to
dependability requirements of these application domains.
Fault-forecasting methods for systems dependability,
dependability modeling thanks to Bayesian networks,
fault-tolerant systems design, formal verification of
control software, timed and probabilistic model-checking,
fault detection and diagnosis of DES for instance, provide
promising solutions for increasing control systems
dependability. Nevertheless, none of these approaches is
able to provide a global solution. Hence, there is a need to
bridge the gaps between the different models, methods
and tools that are proposed so as to improve design and
operation of dependable control of DES.

Gathering researchers of these two communities, this
workshop will favour exchanges and will contribute to a
better interdisciplinary approach for control dependability
improvement. Works focusing on dependability
improvement when designing and implementing the
system ("off-line" approaches) as well as during system
operation ("on-line" approaches) will be considered.

Topics: 

The workshop will cover all topics related to
specification, design, implementation and operation of
dependable controllers for critical DES, including (but not
limited to) the following:

- Recent advances in fault-forecasting methods
- Formal methods for timed and probabilistic systems
- Modeling and analysis of stochastic systems
- Monitoring and diagnosis of discrete event systems
- Control of fault-tolerant discrete event systems
- Reconfiguration methods
- Interdisciplinary approaches for dependability
  improvement
- Applications to manufacturing and production
  systems, transport, power plants, mechatronics and
  embedded systems
- Safety-critical systems
- System security

Special Sessions:

Proposals for special sessions related to specification,
design, implementation and operation of dependable
controllers for critical discrete systems are encouraged.
A special session should consist of 4 to 6 papers in the
format described for individual contributions and a onepage
abstract summarising the aim and content of the
session. This abstract should contain: a title for the
session, the name and full address of the session
organizer, a list of keywords and the list of the papers
included. Survey papers at the beginning of special
sessions are encouraged.

Paper Submissions:

On-line electronic full paper submission is required (PS,
PDF or Word file). Papers must be submitted not later
than January 8, 2009 only by web server application :
http://dcds09.poliba.it

To be included in preprints and proceedings, papers are
limited to 6 pages and have to conform to IFAC
instructions, which can be found at the following address:
http://www.elsevier.com/homepage/saf/ifac/site/IPV%20overview.htm
The copyright transfer form can be downloaded at:
http://www.elsevier.com/homepage/saf/ifac/site/IPV%20copyright.htm

Important Dates:

January 08, 2009: Submission of full papers and
                  special sessions.
March 12, 2009 : Notification of acceptance.
April 12, 2009 : Submission of final camera-ready
                 papers and registration.

Conference Secretariat:

DCDS'09 DEE, Politecnico di Bari
200, via Re David
70125 Bari, Italy
Phone: +39 080 5963643 Fax: +39 080 5963410
http://dcds09.poliba.it
For inquiries, email conference secretariat at:
dcds09@deemail.poliba.it

web site: click here

Contributed by: Ryan Leduc <leduc aT mcmaster dOt ca>

17TH IEEE MEDITERRANEAN CONFERENCE ON CONTROL AND AUTOMATION
MAKEDONIA PALACE HOTEL, THESSALONIKI, GR
June 24 - 26, 2009

January 15, 2009: Contributed, papers, invited session proposals,
Workshop / Tutorial proposals, due.

The 17th IEEE Mediterranean Conference on Control and Automation,
MED'09, will be held in Thessaloniki, Greece. Thessaloniki, the
Cultural Capital of Europe 1997, is a beautiful port city on the Aegean
Sea. It is the centre of the Greek North and the country' s second
largest city. The conference venue is the seafront Makedonia Palace
Hotel.

The conference, through its technical program, will provide a unique
opportunity for the academic and industrial community to address new
challenges, share solutions and discuss future research directions. A
broad range of topics is proposed, following current trends of
combining control/systems theory with software/communication
technologies. For up-to-date information on MED'09, visit
http://www.med09.org


Topics
 
Adaptive control
Aerospace control
Agents & agent-based systems
Approximation-based control
Biologically inspired systems, control
Computational intelligence
Computer controlled systems
Computing & communications
Decentralized control
Discrete event systems
Distributed systems
Education & training
Embedded control systems
Fuzzy systems
Genetic & evolutionary computation
Hybrid systems
Image processing
Industrial automation, manufacturing
Intelligent control systems
Intelligent transportation systems
Linear systems
Marine control
Modeling & simulation
Network control
Neural networks
Non-linear systems
Optimization
Petri nets
Power systems
Predictive control
Process control
Real-time control
Robotics
Robust control
Spectral estimation
Swarms
Systems biology


General Chairs:
Vassilios Petridis, Automation & Robotics Lab, Dept. of Electrical &
Computer Engineering, Aristotle University of Thessaloniki, Greece,
petridis@eng.auth.gr

Frank L. Lewis, Automation & Robotics Research Institute, The
University of Texas at Arlington, lewis@uta.edu

web site: click here

Contributed by: Ryan Leduc <leduc aT mcmaster dOt ca>

SELECTIONS FROM IEEE TRANSACTIONS ON AUTOMATIC CONTROL
VOLUME: 53, ISSUE: 4
MAY, 2008

1) Consensus in Noncooperative Dynamic Games: A Multiretailer Inventory
Application

Bauso, D.; Giarra, L.; Pesenti, R.

Abstract: 

We focus on Nash equilibria and Pareto optimal Nash equilibria for a
finite horizon noncooperative dynamic game with a special structure of
the stage cost. We study the existence of these solutions by proving
that the game is a potential game. For the single-stage version of the
game, we characterize the aforementioned solutions and derive a
consensus protocol that makes the players converge to the unique Pareto
optimal Nash equilibrium. Such an equilibrium guarantees the interests
of the players and is also social optimal in the set of Nash
equilibria. For the multistage version of the game, we present an
algorithm that converges to Nash equilibria, unfortunately, not
necessarily Pareto optimal. The algorithm returns a sequence of joint
decisions, each one obtained from the previous one by an unilateral
improvement on the part of a single player. We also specialize the game
to a multiretailer inventory system.

2) Passivity Analysis and Passification of Discrete-Time Hybrid Systems

Bemporad, A.; Bianchini, G.; Brogi, F.

Abstract: 

For discrete-time hybrid systems in piecewise affine or piecewise
polynomial (PWP) form, this note proposes sufficient passivity analysis
and synthesis criteria based on the computation of piecewise quadratic
or PWP storage functions. By exploiting linear matrix inequality
techniques and sum of squares decomposition methods, passivity analysis
and synthesis of passifying controllers can be carried out through
standard semidefinite programming packages, providing a tool
particularly important for stability of interconnected heterogenous
dynamical systems.

web site: click here

Contributed by: Ryan Leduc <leduc aT mcmaster dOt ca>

SELECTIONS FROM CONTROL ENGINEERING PRACTICE
VOLUME 16, ISSUE 9
SEPTEMBER, 2008

1) Systematic supervisory control solutions for under-load tap-changing
transformers

A. Afzalian, Ali Saadatpoor, W.M. Wonham

Abstract: 

Discrete-event systems (DES) can be found as essential integrated
subsystems in many complex systems, e.g. electrical power systems.
Under-load tap-changing (ULTC) transformers which obviously have
discrete-event behavior are widely used in transmission systems to take
care of instantaneous variations in the load conditions in substations.
In this paper, the voltage control problem in ULTC is solved in
different modes of operation, using DES-based solutions. These
solutions include: DES supervisory control, timed DES supervisory
control and a hierarchical structure for the control system. It is
shown that the specifications are controllable and the closed-loop
control system is non-blocking.

web site: click here

Contributed by: Ryan Leduc <leduc aT mcmaster dOt ca>

DISCRETE EVENT DYNAMIC SYSTEMS
VOLUME 18 NUMBER 3
SEPTEMBER, 2008

1) Lose Fat, Not Muscle: An Examination of Supervisor Reduction in
Discrete-Event Systems

Sarah-Jane Whittaker and Karen Rudie  

Abstract: 

This paper is concerned with the elimination of unnecessary states in
discrete-event system control agents. Several approaches to supervisor
reduction are studied and a new relation between agents, comparability,
is defined to encapsulate most of the concepts found in the
aforementioned methods. This relation is also proven to be preserved
under conjunction, which is commonly employed to determine the
centralized representation of two decentralized DES supervisors.

2) On-Line Monitoring of Large Petri Net Models Under Partial
Observation

 George Jiroveanu, Rene K. Boel and Behzad Bordbar  

Abstract: 

We consider a Petri Net model of the plant. The observation is given by
a subset of transitions whose occurrence is always and immediately
sensed by a monitoring agent. Other transitions not in this subset are
silent (unobservable). Classical on-line monitoring techniques, which
are based on the estimation of the current state of the plant and the
detection of the occurrence of undesirable events (faults), are not
suitable for models of large systems due to high spatial complexity
(exponential in the size of the entire model). In this paper we propose
a method based on the explanation of plant observation. A legal trace
minimally explains the observation if it includes all unobservable
transitions whose firing is needed to enable the observed transitions.
To do so, starting from an observable transition, using backward search
techniques, a set of minimal explanations is derived, which are
sufficient for detecting whether a fault event must have occurred for
sure in the plant or not. The technique also allows production of a set
of basis markings for the estimation of the current state of the plant.
The set of all possible current markings can then be characterized as
the unobservable reach of these basis markings. The computational
complexity of the algorithm depends on the size of the largest
connected subnet which includes only unobservable transitions. This
allows monitoring of plants of any size in which there is no large
unobservable subnet. We also illustrate the applicability of the method
for the monitoring of a class of infinite state systems, unbounded
Petri Nets with unobservable trap circuits, and we show how this can be
useful for distributed implementations.

3) Full access to content Throughput-Optimal Sequences for Cyclically
Operated Plants 

Eckart Mayer, Utz-Uwe Haus, Joerg Raisch and Robert Weismantel	

In this paper, we present a method to determine globally optimal
schedules for cyclically operated plants where activities have to be
scheduled on limited resources. In cyclic operation, a large number of
entities is processed in an identical time scheme. For strictly cyclic
operation, where the time offset between entities is also identical for
all entities, the objective of maximizing throughput is equivalent to
the minimization of the cycle time. The resulting scheduling problem is
solved by deriving a mixed integer optimization problem from a discrete
event model. The model includes timing constraints as well as open
sequence decisions for the activities on the resources. In an
extension, hierarchical nesting of cycles is considered, which often
allows for schedules with improved throughput. The method is motivated
by the application to high throughput screening plants, where a
specific combination of requirements has to be obeyed (e.g. revisited
resources, absence of buffers, or time window constraints).

4) Diagnosability Analysis of a Class of Hierarchical State Machines

Andrea Paoli and Stephane Lafortune  

This paper addresses the problem of fault detection and isolation for a
particular class of discrete event dynamical systems called
hierarchical finite state machines (HFSMs). A new version of the
property of diagnosability for discrete event systems tailored to HFSMs
is introduced. This notion, called L1-diagnosability, captures the
possibility of detecting an unobservable fault event using only high
level observations of the behavior of an HFSM. Algorithms for testing
L1-diagnosability are presented. In addition, new methodologies are
presented for studying the diagnosability properties of HFSMs that are
not L1-diagnosable. These methodologies avoid the complete expansion of
an HFSM into its corresponding flat automaton by focusing the expansion
on problematic indeterminate cycles only in the associated extended
diagnoser.

5) On the Minimization of Communication in Networked Systems with a
Central Station

Weilin Wang, Stephane Lafortune and Feng Lin  

The problem of minimizing communication in a distributed networked
system is considered in a discrete-event formalism where the system is
modeled as a finite-state automaton. The system consists of a central
station and a set of N local agents, each observing a set of local
events. The central station needs to know exactly the state of the
system, whereas local agents need to disambiguate certain pre-specified
pairs of states for purposes of control or diagnosis. This requirement
is achieved by communication, which occurs only between the central
station and the local agents but not among the local agents. A
communication policy is defined as a set of event occurrences to be
communicated between the central station and the local agents. A
communication policy is said to be minimal if any removal of
communication of event occurrences will affect the correctness of the
solution. Under an assumption on the absence of cycles (other than
self-loops) in the system model, this paper presents an algorithm that
computes a minimal communication policy in polynomial time in all
parameters of the system. These results improve upon previous
algorithms for solving minimum communication problems.

web site: click here

Contributed by: Ryan Leduc <leduc aT mcmaster dOt ca>

SELECTIONS FROM IEEE TRANSACTIONS ON SOFTWARE ENGINEERING
VOLUME: 34, ISSUE: 3
MAY, 2008

1)  Characterizing Communication Channel Deadlocks in Sequence Diagrams

 Mitchell, Bill 

Abstract: 

UML sequence diagrams (SDs) are a mainstay of requirements
specifications for communication protocols. Mauw and Reniers' algebraic
(MRA) semantics formally specifies a behaviour for these SDs that
guarantees deadlock free processes. Practitioners commonly use
communication semantics that differ from MRA, which may result in
deadlocks. For example FIFO, token ring, etc. We define a process
algebra that is an extension of the MRA semantics for regular sequence
diagrams. Our algebra can describe several commonly used communication
semantics. Regular SDs are constructed from concurrent message flows
via iteration, branching, and sequential composition. Their behaviour
is defined in terms of a set of partial orders on the events in the SD.
Such partial orders are known as causal orders. We define partial order
theoretic properties of a causal order that are particular kinds of
race condition. We prove any of the common communication semantics we
list either guarantees deadlock free SDs or can result in a deadlock if
and only if a causal order of an SD contains one of these types of race
condition. This describes a complete classification of deadlocks as
specific types of race condition.

web site: click here