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. Announcements
 2.1 Newsletter Moving to Monthly Schedule

3. Conferences
 3.1 African Control Conference 2006, Durban, South Africa, July 5 - 7, 2006
 3.2 CESA2006 Multiconference on, Beijing, China, October 4 - 6, 2006
 3.3 HSCS 06 9th INTERNATIONAL WORKSHOP ON HYBRID SYSTEMS: COMPUTATION AND
     CONTROL, Santa Barbara, California, March 29 - 31, 2006
 3.4 IEEE CIS-RAM 2006, Bangkok, Thailand, June 7 - 9, 2006
 3.5 AUTOMATIC CONTROL, MODELLING and SIMULATION (ACMOS '06), Prague, Czech
     Republic, March 12 - 14, 2006
 3.6 11th International Conference on Algebraic Methodology and Software
     Technology (AMAST '06), Kuressaare, Estonia, July 5 - 8, 2006
 3.7 MECHATRONICS 2006 - 4th IFAC-Symposium on Mechatronic Systems,
     Heidelberg, Germany, September 12 - 14, 2006

4. Journals
 4.1 Selections from IEEE Transactions on Software Engineering, Vol. 31, No.
     11, November 2005
 4.2 Selections from IEEE Systems, Man, and Cybernetics - Part B: Cybernetics,
     Volume 35: Issue:6, December 2005
 4.3 Selections from Control Engineering Practice, Volume: 14 Issue: 4, April
     2006

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

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

Personal note from the editor:

Welcome to the December issue of the DESTC newsletter.

Ryan Leduc

Contributed by: Ryan Leduc <leduc At mcmaster Dot ca>

NEWSLETTER MOVING TO MONTHLY SCHEDULE

As decided at the CDC'05 meeting of the committee, the DESTC newsletter will
be moving to a monthly publication schedule. From now on, the newsletter will
be going out shortly after the 15th of each month.  As long as your
submission has been sent by the 15th, it should appear in that month's
newsletter.

Contributed by: Mariagrazia Dotoli <dotoli@deemail.poliba.it>

AFRICAN CONTROL CONFERENCE 2006
Durban, South Africa
July 5 - 7, 2006

African Control Conference 2006
University of KwaZulu Natal
Durban, South Africa
5-7 July 2006

You are invited to participate in the 2006 African Control Conference. The 
conference aims to stimulate communication between researchers and 
practitioners of automatic control, with particular emphasis on those 
working in Africa, or on problems involving African industries. In 
particular, researchers from Africa who are working internationally are 
encouraged to visit and renew contact with researchers working in Africa.

Application, tutorial, and theoretical papers are invited in the areas of 
control, instrumentation, automation, process industry and intelligent 
systems. Papers in the academic track will be selected based on peer review 
of the full paper. Papers in the industry track will be accepted based on an 
extended (500-word) abstract.

Important Dates
28 April 2006 Receipt of full papers for academic track and extended 
abstracts for industry papers
22 May 2006 Notification of acceptance
9 June 2006 Receipt of camera-ready final papers

To facilitate travel arrangements, the Organising Committee will give early 
notification of acceptance for papers received and reviewed before the above 
deadline dates.

For further information, visit www.sacac.org.za
SACAC (South African Council for Automation and Computation) is the 
nominated National Member Organisation for South Africa to the International 
Federation of Automatic Control.

Web site: click here

Contributed by: Mariagrazia Dotoli <dotoli@deemail.poliba.it>

CESA2006 MULTICONFERENCE ON
Beijing, China
October 4 - 6, 2006

The Multiconference on "Computational Engineering in Systems Applications" 
will be held on October 4-6, 2006 in Beijing, China. http://cesa2006.ec-
lille.fr/

The aim of this important meeting is to make the state of the art of the 
various theoretical and practical aspects of computational engineering 
involved in system theory and its applications. 

The five parts of the Multiconference will be:
Symposium on: Mathematical Modeling, Identification and Simulation 
Symposium on: Cybernetics and Computational Intelligence 
Symposium on: Aeronautics and Astronautics 
Symposium on: Computer Science and Industrial Engineering 
Symposium on: Communication and Electronic Systems  

Important dates:
February 1, 2006:  Submission of organized sessions proposals 
March 1, 2006:	   Submission of draft papers and invited sessions 
April 15, 2006:    Notification of acceptance. 
June 1, 2006:	   Deadline for submission of final papers. 

The main application areas considered during the multiconference will be:
Aeronautics and Astronautics. Automation. Banking and Finance. Biomedical 
Engineering. Car Industry. Chemical Engineering. Components and 
Instrumentation. Economics and Management. Electrical Engineering. Energy 
Systems.  Environmental Systems. Food Industry. Industrial Engineering 
Integrated Manufacturing. Marine and Off-Shore Control. Medicine. Robotics. 
Telecommunications. Textile Industry. Transportation Systems. Utilities.

Web site: click here

Contributed by: Mariagrazia Dotoli <dotoli@deemail.poliba.it>

HSCS 06 9TH INTERNATIONAL WORKSHOP ON HYBRID SYSTEMS: COMPUTATION AND CONTROL
Santa Barbara, California
March 29 - 31, 2006

9th INTERNATIONAL WORKSHOP ON HYBRID SYSTEMS: COMPUTATION AND CONTROL
March 29-31, 2006
Santa Barbara, California
http://hscc06.csl.sri.com/

The 9th International Workshop on Hybrid Systems: Computation and Control 
(HSCC 2006), will be held in Santa Barbara, California, from March 29-31, 
2006. The annual workshop on hybrid systems attracts researchers from 
academia and industry interested in modeling, analysis, and implementation 
of dynamic and reactive systems involving both discrete and continuous 
behaviors.

TOPICS
Submissions are invited in all areas pertaining to the design, analysis, 
implementation, and applications of hybrid systems. Topics of interest 
include, but are not limited to:
. Modeling and representations
. Computability and complexity issues
. Tools for analysis and verification
. Tools for synthesis and design
. Programming language support and implementation . Control and 
optimization . Hybrid models in biology and other sciences . Engineering 
applications such as automotive, avionics, power systems, transportation, 
manufacturing, and robotics 

SUBMISSIONS
The conference proceedings will be published in the Springer Lecture Notes 
in Computer Science series. Submitted papers must present original, 
unpublished research that has not been submitted elsewhere. Instructions for 
submitting the papers electronically will be available on the conference 
webpage. 

POSTER SESSION
This year's workshop will include a poster session in addition to the 
regular oral presentations. The poster session is aimed at advertising new 
or ongoing work, as well as getting feedback from the HSCC community. We are 
particularly interested in presentations of student work. To submit a 
poster, please send a proposal of one page or less describing the nature of 
poster.

IMPORTANT DATES

Submission deadline for regular papers: October 3, 2005   (regular paper 
submission closed)
Submission deadline for posters:	December 2,  2005
Conference:				March 29-31, 2006

Workshop Co-Chairs 
Joao P. Hespanha
University of California, Santa Barbara
E-mail: hespanha@ece.ucsb.edu 

Ashish Tiwari
SRI International, Menlo Park, CA
E-mail: tiwari@csl.sri.com

Web site: click here

Contributed by: Mariagrazia Dotoli <dotoli@deemail.poliba.it>

IEEE CIS-RAM 2006
Bangkok, Thailand
June 7 - 9, 2006

2006 IEEE CIS-RAM
7-9 June 2006, Bangkok, Thailand
http://www.ntu.edu.sg/cis-ram/.

Following the success of CIS-RAM 2004 (http://cis-ram.nus.edu.sg) in 
Singapore, the IEEE R&A and SMC Singapore Chapters are again jointly 
organizing two conferences from 7-9 June, 2006, in Bangkok, Thailand:

(i) IEEE International Conference on Cybernetics and Intelligent Systems 
	(IEEE CIS'06),
(ii) IEEE International Conference on Robotics, Automation and 
	Mechatronics (IEEE RAM'06).

The goal of the 2006 IEEE CIS-RAM is to bring together experts from 
different expertise areas and from different countries to discuss on the 
state-of-the-art and to present new research findings and perspectives of 
future developments with respect to the conference themes. This is an 
integration of the two conferences (CIS'06 and RAM'06) that will be held in 
parallel at the same venue in Bangkok, Thailand.

The proceedings of IEEE CIS and IEEE RAM will be indexed in the EI 
Compendex  Database. Best Student Paper Awards for both IEEE CIS 2006 and 
IEEE RAM 2006 will be presented.

PAPER SUBMISSION:
Papers must be written in English and should describe original research 
work. Author of accepted papers will be required to register and present 
their papers.

Registration to any one of the conferences will entitle a participant to the 
technical sessions and the proceedings of both conferences, as well as the 
joint conference banquet and buffet lunches.

INVITED SESSIONS:
The conferences will feature invited sessions on specialized topics of 
interests. The invited sessions are intended to usher in, in-depth 
discussions in special areas relevant to the conference theme. The session 
organizers will coordinate the associated review process. All accepted 
papers from the invited sessions will be included in the conference 
proceedings.

The conferences are currently soliciting proposals for invited sessions. For 
instructions on proposing and organizing an invited session, please go to 
http://www.ntu.edu.sg/cis-ram/callsessions.htm.

Important dates:
Invited Session Summary Submission		    :  1 January 2006
Conference / Invited Session Paper Submission	    : 15 January 2006
Notification of Acceptance			    :  1 March 2006
Final Camera-Ready Manuscript			    :  1 April 2006
Advance Registration Deadline			    :  1 April 2006
Conference					    :  7 - 9 June 2006

For details, please visit the conference website: 
http://www.ntu.edu.sg/cis-ram/

Web site: click here

Contributed by: Mariagrazia Dotoli <dotoli@deemail.poliba.it>

AUTOMATIC CONTROL, MODELLING AND SIMULATION (ACMOS '06)
Prague, Czech Republic
March 12 - 14, 2006

8th WSEAS  International Conference on
AUTOMATIC CONTROL, MODELLING and SIMULATION (ACMOS '06)
Prague, Czech Republic, March 12-14, 2006 
www.worldses.org/conferences/2006/prague/acmos

Sponsored by WSEAS and WSEAS Transactions

The organizing committee calls you to submit your papers.
   
INDEXES:
The Proceedings related to these meetings are covered: INSPEC (IEE), AMS 
(American Mathematical Soceity), Mathematical Reviews, ZENTRABLATT, ISI 
(ISINET), ELSEVIER, CSA, ELP, NLG, Engineering Index, Directory of Published 
Proceedings,British Library, Swets Information Services, etc... More 
Details:   www.worldses.org/indexes 
 
JOURNAL PUBLICATION: 
The authors of the best papers will be invited to send extended versions of 
their papers to various international reputable journals. However, these 
papers must be of high-quality (break-through work).
 
STUDENTS COMPETITION:
WSEAS will give out prizes for the winners of the students competition:  
First Prize, Second Prize, Third Prize. 

History of WSEAS Conferences on Automatic Control, Modelling and Simulation:
The first WSEAS Conference on Control was held in Vravrona, Greece, December 
2000.
The second one was held in Cairns, Australia, December 2001.
The third one in Miedzyzdroje, Poland, in September of 2002.
The 4th in Malta in September of 2003 
The 5th in Miami, USA, in April 2004
The 6th in Corfu, Greece, in August of 2004
The 7th WSEAS Conference on Control under the name: WSEAS Conference on 
Automatic Control, Modelling and Simulation took place in Prague, Czech 
Republic on March of 2005.

Accomodation in the Hotel - Registration
========================================= 
Contact us

Comments from the recent WSEAS Conferences:
=========================================
www.worldses.org/feedback2005.txt 

SPEAKERS-TOPICS-COMMITTEES:
==========================
http://www.worldses.org/conferences/2006/prague/acmos

CONFERENCE REPORT
====================
See also a report from the most recent WSEAS 
Conferences in the web
www.wseas.org/reports

REVIEWERS: 
=========
The list of the reviewers will be available in the conference proceedings + 
journals
as well as ON-LINE. See for example:
www.worldses.org/reviewers.htm

BEST PAPERS' AWARD:
====================
We will follow a procedure similar to the procedure of the recent
WSEAS conferences
www.wseas.org/reports

E-LIBRARY: 
====================
All the members of WSEAS as well as all the authors and co-authors 
that have published papers in the WSEAS conferences (since 1996) have now a
username and a password without expiry date. The log files of the server 
counts
30000 visits per month now in the on-line E-library. 
www.worldses.org/online/download.htm

Web site: click here

Contributed by: Ryan Leduc <leduc At mcmaster Dot ca>

11TH INTERNATIONAL CONFERENCE ON ALGEBRAIC METHODOLOGY AND SOFTWARE
TECHNOLOGY (AMAST '06)
Kuressaare, Estonia
July 5 - 8, 2006

		       CALL FOR PAPERS

		       Conference colocated with MPC '06

Background

The major goal of the AMAST conferences is to promote research that
may lead to the setting of software technology on a firm, mathematical
basis. This goal is advanced by a large international cooperation with
contributions from both academia and industry. The virtues of a
software technology developed on a mathematical basis have been
envisioned as being capable of providing software that is (a) correct,
and the correctness can be proved mathematically, (b) safe, so that it
can be used in the implementation of critical systems, (c) portable,
i.e., independent of computing platforms and language generations, and
(d) evolutionary, i.e., it is self-adaptable and evolves with the
problem domain.

The previous conferences were held in Iowa City, Iowa, USA (1989, 1991
and 2000), Twente, The Netherlands (1993), Montreal, Canada (1995),
Munich, Germany (1996), Sydney, Australia (1997), Manaus, Amazonia,
Brazil (1998), Reunion Island, France (2002) and Stirling, UK (2004,
colocated with MPC' 04). The 2006 conference will be held at
Kuressaare, Estonia, colocated with MPC '06.

The conference series has become widely known for disseminating
academic and industrial achievements within the broad AMAST areas
of interest. Through these meetings AMAST has attracted an international
following among researchers and practitioners interested in software
technology, programming methodology and their algebraic and logical
foundations.


Important dates

    * Submission of abstracts: 27 January 2006
    * Submission of full papers: 3 February 2006
    * Notification of authors: 17 March 2006
    * Camera-ready version: 14 April 2006

Topics

Topics of interest include, but are not limited to, the following:

SOFTWARE TECHNOLOGY:

    * systems software technology
    * application software technology
    * concurrent and reactive systems
    * formal methods in industrial software development
    * formal techniques for software requirements, design
    * evolutionary software/adaptive systems

PROGRAMMING METHODOLOGY:

    * logic programming, functional programming, object paradigms
    * constraint programming and concurrency
    * program verification and transformation
    * programming calculi
    * specification languages and tools
    * formal specification and development case studies

ALGEBRAIC AND LOGICAL FOUNDATIONS:

    * logic, category theory, relation algebra, computational algebra
    * algebraic foundations for languages and systems, coinduction
    * theorem proving and logical frameworks for reasoning
    * logics of programs
    * algebra and coalgebra

SYSTEMS AND TOOLS (for system demonstrations or ordinary papers):

    * software development environments
    * support for correct software development
    * system support for reuse
    * tools for prototyping
    * component based software development tools
    * validation and verification
    * computer algebra systems
    * theorem proving systems

Submission

Two kinds of submissions are solicited for this conference: technical
papers and system demonstrations.  Papers may report academic or
industrial progress, and papers which deal with both are especially
well-regarded.

Submission is in two stages. Abstracts (plain text) must be submitted
by 27 January 2006. Full papers (pdf) adhering to the llncs style and
not longer than 15 pages (6 pages for system demonstrations) must be
submitted by 3 February 2006. The web-based submission system will
open in early January 2006. Papers must report previously unpublished
work and not be submitted concurrently to another conference with
refereed proceedings. Accepted papers must be presented at the
conference by one of the authors.

All papers will be refereed by the programme committee, and will be
judged based on their significance, technical merit, and relevance
to the conference.

Publication

As in the past the proceedings of AMAST '06 will be published in the
Lecture Notes in Computer Science series of Springer-Verlag.

In the past the best papers from AMAST have been published in a
special issue of the journal Theoretical Computer Science and it
is expected that this practice will be continued for AMAST '06.

Programme Committee Chairs

Michael Johnson, Macquarie University (co-chair)
Varmo Vene, University of Tartu (co-chair)

AMAST steering committee

Egidio Astesiano, Universita degli Studi di Genova
Robert Berwick, MIT
Zohar Manna, Stanford University
Michael Mislove, Tulane University
Anton Nijholt, University of Twente
Maurice Nivat, Universite Paris 7
Charles Rattray, University of Stirling
Teodor Rus, University of Iowa
Giuseppe Scollo, Universita degli Studi di Verona
Michael Sintzoff, Universite Catholique de Louvain
Jeannette Wing, Carnegie Mellon University
Martin Wirsing, Ludwig-Maximilians-Universitaet Muenchen
Michael Johnson, Macquarie University (chair)

Venue

Kuressaare (pop. 16000) is the main town on Saaremaa, the
second-largest island of the Baltic Sea. Kuressaare is a charming
seaside resort on the shores of the Gulf of Riga highly popular with
Estonians as well as visitors to Estonia.

The scientific sessions of MPC/AMAST 2006 will take place at Saaremaa
Spa Hotel Meri, one among the several new spa hotels in the town. The
social events will involve a number of sites, including the
14th-century episcopal castle. Accommodation will be at Saaremaa Spa
Hotels Meri and Ruutli.

To get to Kuressaare and away, one must pass through Tallinn
(pop. 402000), Estonia's capital city. Tallinn is famous for its
picturesque medieval Old Town, inscribed on UNESCO's World Heritage
List.

Local organizers

MPC/AMAST 2006 is organized by Institute of Cybernetics, a research
institute of Tallinn Univ. of Technology.

The local organizers are Tarmo Uustalu (chair), Monika Perkmann, Juhan
Ernits, Ando Saabas, Olha Shkaravska, Kristi Uustalu.

Contact email addresses: mike(at)ics.mq.edu.au, varmo(at)cs.ut.ee.

Web site: click here

Contributed by: Ryan Leduc <leduc At mcmaster Dot ca>

MECHATRONICS 2006 - 4TH IFAC-SYMPOSIUM ON MECHATRONIC SYSTEMS
Heidelberg, Germany
September 12 - 14, 2006

Second Announcement and Call for Papers

Sponsor
IFAC International Federation of Automatic Control
Technical Committee of Mechatronic Systems
In cooporation with
* Institute of Electrical and Electronics Engineers (IEEE)
* American Society of Mechanical Engineers (ASME)

Organizers
* VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik (GMA)
* Technische Universität Dresden, Institute of Automation

Scope:
Mechatronic systems comprise the synergetic functional and
spatial integration of mechanical components with electronic
systems and embedded information technology. This design
paradigm results in innovative, smart and intelligent products.
Faster innovation cycles required by the markets and evolving
advances in materials and microelectronics call for improved
engineering solutions in this challenging multi-disciplinary
field.

Automatic control plays a traditional strong role for the design of
mechatronic systems. The feedback principle forms the basis for
every controlled motion and understanding, influencing the
dynamic interaction between mechatronic components is mandatory
for robust product operation and machine intelligence offers
new perspectives in system autonomy.

The goal of this Symposium is to continue the successful IFAC
symposium series on mechatronic systems (2000 Darmstadt,
2002 Berkeley, 2004 Sydney) and to bring together experts in
this interdisciplinary field from all over the world. The
Symposium will give an overview of the state-of-the-art and
will show the leading-edge research results and developments.
The Symposium on Mechatronic Systems 2006 will be held in
conjunction with the anniversary event "50 Years of IFAC"
which will be celebrated on September 15th in Heidelberg.

Topics:
A. Methods and tools for multi-disciplinary systems
development
modelling, design, simulation, test, verification, rapid
prototyping, manufacturing and assembly
Area Chair: A. Kugi (DE)

B. Control of mechatronic systems
nonlinear control, nonlinear estimation and filtering, robust
control, adaptive control, repetitive control, discrete event
control, hybrid control, optimal control, vibration and motion
control, etc.
Area Chair: M. Tomizuka (US)

C. Reliability, safety and systems integrity
reliability engineering, diagnosis, health monitoring, fault
tolerance, failure management, etc.
Area Chair: R. Isermann (DE)

D. Human-machine interaction
haptic interfaces, force feedback, impedance control, visual
servoing, etc.
Area Chair: H. Hashimoto (JP)

E. Mechatronic components and devices
actuator and sensor systems, non-conventional sensors and
actuators, semi-active and active components, magnetic
bearings, etc.
Area Chair: R. Moheimani (AU)

F. Information processing
identification and adaptation, embedded computer
technology, signal processing, sensor fusion, sensors
networks, machine vision, navigation
Area Chair: B. Yao (US)

G. Mechatronic systems and applications
automotive systems, transportation systems (trains, marine,
aerospace), mobile systems and locomotion, engines, robotics,
micro-/nano-systems, MEMS, precision mechatronic systems
(optical systems, machine tools), data storage systems, smart
structures, medical systems
Area Chair: R. Goodall (UK)

Industrial Contributions Chair
Papers with strong industrial involvement and particular
industry relevant contents (minimum one industrial partner)
Chair: H.P. Schoener, DaimlerChrysler (DE)

Plenary and Semiplenary Sessions
Proposals to be submitted to IPC-chair:
janschek@tu-dresden.de

Best Paper Awards
Awards will be given in 2 categories:
* Young Author Paper Award
(presenter younger than 35 years at registration)
* Conference Best Paper Award

Submission of Papers:
Please submit electronically your draft paper (A4 size) with 4-6
pages in English not later than January 15th, 2006 via the homepage
www.mechatronics2006.com. The draft paper should clearly
indicate the merits of the new contributions and the relevance
to the theme of mechatronic systems. Only un published papers
may be submitted.
Please structure the first page as follows: (1) Title, (2) authors,
complete address(es), affiliations, phone/fax number, email address,
(3) classification symbol according to topics (e.g. D), 10 keywords.
The draft paper should show the main contributions, figures,
equations etc. and related literature to allow a fair reviewing
procedure by the International Program Committee.

Deadlines:
Proposals for invited sessions: 15 January 2006
Submission of contributed papers: 15 January 2006
Notification of acceptance: 15 March 2006
Submission of final papers: 19 June 2006

Venue:
The Symposium will be held at the Ruprecht-Karls-University in
Heidelberg, the city where the event "50 Years of IFAC" will be
celebrated on September 15th, 2006.
Heidelberg
The name stands for the world-famous Castle and a picturesque
Old Town in breathtakingly beautiful surroundings. It stands
both for Germany's oldest university and modern research
facilities, for historic streets and a lively university atmosphere,
for total relaxation and beautiful walks, plus stimulating international
conferences and festivals. It also stands for the longest
and one of the most attractive pedestrian zones in Europe.

Symposium Style:
The Symposium will include plenary papers, contributed and
invited paper presentation, poster sessions and discussion
sessions.
The official Symposium language is English.
The registration fee will be about 490 EUR + VAT for all
participants.

Web site: click here

Contributed by: Ryan Leduc <leduc AT mcmaster DoT ca>

SELECTIONS FROM IEEE TRANSACTIONS ON SOFTWARE ENGINEERING
VOL. 31, NO. 11
NOVEMBER, 2005

1) Correctness Verification and Performance Analysis of Real-Time Systems
Using Stochastic Preemptive Time Petri Nets

Giacomo Bucci, Luigi Sassoli, Enrico Vicario

Abstract: 

Time Petri Nets describe the state of a timed system through a marking and a
set of clocks. If clocks take values in a dense domain, state space analysis
must rely on equivalence classes. These support verification of logical
sequencing and quantitative timing of events, but they are hard to be
enriched with a stochastic characterization of nondeterminism necessary for
performance and dependability evaluation. Casting clocks into a discrete
domain overcomes the limitation, but raises a number of problems deriving
from the intertwined effects of concurrency and timing. We present a
discrete-time variant of Time Petri Nets, called stochastic preemptive Time
Petri Nets, which provides a unified solution for the above problems through
 the adoption of a maximal step semantics in which the logical location
evolves through the concurrent firing of transition sets. We propose an
analysis technique, which integrates the enumeration of a succession relation
among sets of timed states with the calculus of their probability
distribution. This enables a joint approach to the evaluation of performance
and dependability indexes as well as to the verification of sequencing and
timeliness correctness. Expressive and analysis capabilities of the model are
demonstrated with reference to a real-time digital control system.

Web site: click here

Contributed by: Emanuel Almeida <almeidae@umich.edu>

SELECTIONS FROM IEEE SYSTEMS, MAN, AND CYBERNETICS - PART B: CYBERNETICS
VOLUME 35: ISSUE:6
DECEMBER, 2005

1) Dynamic Algorithms for the Shortest Path Routing Problem: Learning 
Automata-Based Solutions

Misra, S.; Oommen, B.J.

Abstract
This paper presents the first Learning Automaton-based solution to the 
dynamic single source shortest path problem. It involves finding the  
hortest path in a single-source stochastic graph topology where there are 
continuous probabilistic updates in the edge-weights. The algorithm is 
significantly more efficient than the existing solutions, and can be used to 
find the "statistical" shortest path tree in the "average" graph topology. 
It converges to this solution irrespective of whether there are new changes 
in edge-weights taking place or not. In such random settings, the proposed 
learning automata solution converges to the set of shortest paths. On the 
other hand, the existing algorithms will fail to exhibit such a behavior, 
and would recalculate the affected shortest paths after each weight-change. 
The important contribution of the proposed algorithm is that all the edges 
in a stochastic graph are not probed, and even if they are, they are not all 
probed equally often. Indeed, the algorithm attempts to almost always probe 
only those edges that will be included in the shortest path graph, while 
probing the other edges minimally. This increases the performance of the 
proposed algorithm. All the algorithms were tested in environments where 
edge-weights change stochastically, and where the graph topologies undergo 
multiple simultaneous edge-weight updates. Its superiority in terms of the 
average number of processed nodes, scanned edges and the time per update 
operation, when compared with the existing algorithms, was experimentally 
established. The algorithm can be applicable in domains ranging from ground 
transportation to aerospace, from civilian applications to military, from 
spatial database applications to telecommunications networking. 

2)Modeling and Deadlock Avoidance of Automated Manufacturing Systems With 
Multiple Automated Guided Vehicles

Wu, N.; Zhou, M.

Abstract
An automated manufacturing system (AMS) contains a number of versatile 
machines (or workstations), buffers, an automated material handling system 
(MHS), and is computer-controlled. An effective and flexible alternative for 
implementing MHS is to use automated guided vehicle (AGV) system. The 
deadlock issue in AMS is very important in its operation and has extensively 
been studied. The deadlock problems were separately treated for parts in 
production and transportation and many techniques were developed for each 
problem. However, such treatment does not take the advantage of the 
flexibility offered by multiple AGVs. In general, it is intractable to 
obtain maximally permissive control policy for either problem. Instead, this 
paper investigates these two problems in an integrated way. First we model 
an AGV system and part processing processes by resource-oriented Petri nets, 
respectively. Then the two models are integrated by using macro transitions. 
Based on the combined model, a novel control policy for deadlock avoidance 
is proposed. It is shown to be maximally permissive with computational 
complexity of O(n^2) where n is the number of machines in AMS if the 
complexity for controlling the part transportation by AGVs is not 
considered. Thus, the complexity of deadlock avoidance for the whole system 
is bounded by the complexity in controlling the AGV system. An illustrative 
example shows its application and power. 

3)Reachability of Nonsynchronized Choice Petri Nets and Its Applications

Chao, D.Y.

Abstract
A new local structure called a second-order structure was proposed to 
generate a new class of nets called synchronized choice nets (SNC). SNC 
covers well-behaved free choice nets. Reachability is no longer P-Space hard 
problem, but can be solved with polynomial time complexity. How to extend 
them to non-SNC and its application to deadlock detection in flexible 
manufacturing systems are discussed. 

4)Monitoring and Fault Diagnosis of Hybrid Systems

Zhao, F.; Koutsoukos, X.; Haussecker, H.; Reich, J.; Cheung, P.

Abstract
Many networked embedded sensing and control systems can be modeled as hybrid 
systems with interacting continuous and discrete dynamics. These systems 
present significant challenges for monitoring and diagnosis. Many existing 
model-based approaches focus on diagnostic reasoning assuming appropriate 
fault signatures have been generated. However, an important missing piece is 
the integration of model-based techniques with the acquisition and 
processing of sensor signals and the modeling of faults to support 
diagnostic reasoning. This paper addresses key modeling and computational 
problems at the interface between model-based diagnosis techniques and 
signature analysis to enable the efficient detection and isolation of 
incipient and abrupt faults in hybrid systems. A hybrid automata model that 
parameterizes abrupt and incipient faults is introduced. Based on this 
model, an approach for diagnoser design is presented. The paper also 
develops a novel mode estimation algorithm that uses model-based prediction 
to focus distributed processing signal algorithms. Finally, the paper 
describes a diagnostic system architecture that integrates the modeling, 
prediction, and diagnosis components. The implemented architecture is 
applied to fault diagnosis of a complex electro-mechanical machine, the 
Xerox DC265 printer, and the experimental results presented validate the 
approach. A number of design trade-offs that were made to support 
implementation of the algorithms for online applications are also described.

Web site: click here

Contributed by: Emanuel Almeida <almeidae@umich.edu>

SELECTIONS FROM CONTROL ENGINEERING PRACTICE
VOLUME: 14 ISSUE: 4
APRIL, 2006

1) Modeling and analysis of fault-tolerant systems for machining operations 
based on Petri nets 

P.E. Miyagi, L.A.M. Riascos

Abstract
This paper introduces a methodology for modeling and analyzing fault-
tolerant manufacturing systems that not only optimizes normal productive 
processes, but also performs detection and treatment of faults. This 
approach is based on the hierarchical and modular integration of Petri nets. 
The modularity provides the integration of three types of processes: those 
representing the productive process, fault detection, and fault treatment. 
The hierarchical aspect of the approach allows us to consider processes on 
different levels of detail (i.e., factory, manufacturing cell, or machine). 
Case studies considering detection and treatment of faults are presented, 
and a simulation tool is applied to verify the models. 

Keywords: Detection and treatment of faults; Manufacturing systems; Fault-
tolerance; Petri nets

Web site: click here