IEEE Robotics and Automation Society, Technical Committee on Discrete Event Dynamic Systems (DEDS TC)
The IEEE Robotics and Automation Society DEDS Technical Committee is chaired by
Professor Tarek Sobh, Department of
Computer Science and Engineering, University
of Bridgeport; and Professor Beno Benhabib of the Department of Mechanical
Engineering, University of Toronto.
Recent committee activities include:
- Organizing a workshop on Discrete Event and Hybrid Systems
for the 1997 IEEE International Conference on Robotics and Automation,
Albuquerque, New Mexico, April 1997. 18 distinguished scientists and
practitioners in the area are scheduled to speak at the workshop.
- Organizing a special issue of the IEEE Robotics and Automation magazine
on DEDS and hybrid systems in robotics and automation.
8 paper submissions received so far, papers are under review.
Issue to appear in June 1997.
- Chairing and organizing a track on Discrete event and
hybrid systems control at the 6th IEEE International Conference on
Emerging Technologies and Factory Automation (ETFA 97) in Tucson,
- Preparing a special issue of the
International Journal on Science and Technology on Robotics and Automation.
9 paper submissions received so far, papers are under review.
Issue to appear in summer 1997.
- Chairing and organizing a track of the Discrete event and
hybrid systems control at the 5th IEEE International Conference on
Emerging Technologies and Factory Automation (ETFA 96) in Hawaii, 11/96
- A review paper has been produced with the title
"A Subject-Indexed Bibliography of DEDS". All interested members
may receive a copy of this paper by contacting either one of the chairpersons.
The paper appeared in the IEEE Robotics and Automation magazine,
Vol. 1, No. 2, June 1994.
- The committee has completed a fairly complete and detailed bibliography
of published books, journal, transaction and conference papers, technical
reports and other research publications related to the DEDS area.
Bibliographic ftp sites have been established for Discrete Event
Systems research (past 10 - 15 years approximately). The above paper
includes directions to access the bibliography.
- The committee co-chairs have edited a special
issue of the Journal of Robotics and Autonomous Systems on
Discrete Event Dynamic Systems in Robotics and Automation.
The special issue appeared in October 1994.
- Working on a graphical software environment the committee
intends to make
public, as a stochastic DEDS automata/petri-net hybrid graphical environment
with timing, control, simulation, and monitoring capabilities.
- Building and maintaining a WWW site for DEDS research,
bibliographies, software, etc.
- Updating and keeping track of the bibliographic ftp sites.
Discrete Event and Hybrid Systems in Robotics and Automation
Hybrid systems, in which digital and analogue devices and sensors interact
over time, is attracting the attention of researchers. Representation
of states and the physical system condition includes continuous and discrete
numerics, in addition to symbols and logical parameters. Most of the current
robotics, automation, and intelligent systems problems, as well as problems
in other domains, fall within
the description of hybrid systems. There are many issues that need to be
resolved, among them, definitions for observability, stability and
stabilizability, controllability in general, uncertainty of state transitions
and identification of the system.
The underlying mathematical representation of complex
computer-controlled systems is still insufficient to create a set of
models which accurately captures the dynamics of the systems over the
entire range of system operation. We remain in a situation where
we must tradeoff the accuracy of our models with the
manageability of the models. Closed-form solutions of mathematical
models are almost exclusively limited to linear system models.
Computer simulation of nonlinear and discrete-event models
provide a means for off-line design of control systems. Guarantees of
system performance are limited to those regions where the
robustness conditions apply. These conditions may not
apply during startup and shutdown or during periods of anomalous
Recently, attempts have been made to model low and high-level system changes
in automated and semi-automatic systems as discrete event dynamic systems
(DEDS). Several attempts to improve the modeling capabilities are focused on
mapping the continuous world into a discrete one. However, repeated results
are available which indicate that large interactive systems evolve into
states where minor events can lead to a catastrophe. Discrete event and hybrid
system formulations have been used in many domains to model and control
system state changes within a
process. Some of the domains include: Manufacturing, Robotics,
Autonomous Agent Modeling, Control Theory, Assembly and Planning,
Concurrency Control, Distributed Systems, Hierarchical Control,
Highway Traffic Control, Autonomous Observation Under Uncertainty,
Operating Systems, Communication Protocols, Real-Time Systems,
Scheduling, and Simulation.
A number of tools and modeling techniques are being used to model
and control discrete event systems in the above domains. Some of the modeling
strategies include: Timed, untimed and stochastic Petri Nets and State
Markovian, Stochastic, and Perturbation models, State Machines,
Hierarchical State Machines, Hybrid Systems Modeling, Probabilistic
Modeling (Uncertainty Recovery and Representation), Queuing Theory,
and Recursive Functions.
The IEEE R&A DEDS TC attempts to serve the robotics and
automation community by organizing and focusing DEDS-related activities
and making different resources available for the DES-related
projects within the R&A domain.
Selected Committee-Related Publications:
- Journal Papers
- T. M. Sobh, J. C. Owen,
K. P. Valavanis, and D. Gracanin, ``A Subject-Indexed Bibliography of Discrete
Event Dynamic Systems.'' In IEEE Magazine on Robotics and Automation,
Vol. 1, No. 2, June 1994.
- T. M. Sobh, J. C. Owen,
and M. Dekhil, ``A Dynamic Recursive Approach for Autonomous Inspection
and Reverse Engineering.'' In Journal of Robotics and Autonomous Systems,
Special Issue on Discrete Event Systems in Robotics and Automation, October
- Conference Papers
- T. M. Sobh, P. Sloan, and M. Dekhil,
``A Graphical Environment and Applications for Discrete Event and Hybrid
Systems in Robotics and Automation''. Submitted to the IEEE/RSJ International
Conference on Intelligent Robots and Systems (IROS 95), Special Session
on Discrete Event and Hybrid Systems, Pittsburgh, August 1995.
Snap shots of the graphical DES environment