PhD position (profile continuous Petri nets)

Wed, 17/01/2007 (All day)
PhD position


Systems Engineering and Discrete Event Systems Group
Department of Computer Science and Systems Engineering
University of Zaragoza,

The activities of the group are related to the modelling, analysis and formal synthesis of some classes of artificial systems that are interesting from a technical point of view (production systems, computer systems, logistic systems, coordination systems, etc.). Usually more adequately modelled by means of discrete event systems formalisms (automata, Petri nets, process algebra, queuing networks,...), the state explosion problem puts a limit to most of the analysis or synthesis techniques. Relaxations based on continuization appear as a possible way to overcome these difficulties when largely populated systems, or systems with high cadence are considered.

The position will be mainly focused on the formalism of continuous Petri nets, defined relaxing the integrality constraint in a similar way as in fluid queuing networks, and more specifically in optimization problems.

On the one hand, static optimization problems like resources optimization (initial marking optimization), equipment selection (rate and firing optimization) or processes and production subsystems (structural optimization).

On the other hand, dynamic control of continuous Petri nets. The desired continuous system controlling is based on the limitation of the firing rate of transitions, in other words, limiting the speed of system actions realization. In this way, the possible actions are restricted: only system slowdown is possible and the actions have a local marking dependent (state) upper limit. This fact makes difficult to use many classical control techniques. Also robustness and sensibility aspects on the controlled system will be addressed.

Once the relaxed model has been analysed or a control synthesized, it is necessary to interpret and to adapt the results for the original model. It may be necessary, for instance, to apply a post-optimization to the discrete reconstruction (reduce the relaxation) from the obtained results. If we are considering a control policy design, we will need to study how to build from that policy a new one for the discrete system but fulfilling the specified requirements.

The main task for the accepted candidate will be to conduct research towards his/her PhD. The candidate is expected to complete the degree within 4 years.

Applicants must have MSc (or equivalent) degree in Computer Science, Mathematics, Electrical/Electronics or Communications Engineering. Knowledge on operational research, automatic control and computer science will be specially welcome.

Application must be done at the web page of the Ministry of Education

For further information contact:

Laura Recalde (lrecaldeatunizar [dot] es)
Departamento de Informática e Ingeniería de Sistemas
Universidad de Zaragoza
Maria de Luna 1,
50018 Zaragoza, Spain