The goal of the project is related to the modelling, analysis and formal synthesis of artificial systems that are interesting from a technical point of view (logistic systems, production systems, computer systems, coordination systems, etc.). These kinds of systems are usually more adequately modelled by means of discrete event systems formalisms (automata, Petri nets, process algebra, queuing networks,...). However, 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. Under this approach, a partial relaxation of discrete models leads to hybrid systems.

More specifically, the project 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. Given a net structure, and an initial state, part of the effort will be devoted to contribute in the definition of the most appropriate evolution semantics. To do that, a catalog of reference models will be compiled, whose evolution will be compared with the original discrete ones. The design of analysis and synthesis methods will also be studied (parametrical optimization, optimal control-scheduling). The appropriate computer tools will also be developed. In a complementary way, continuous Petri nets models will be compared with alternative models like positive or compartmental systems.

Technical questions to consider:

1.- Modelling
2.- Analysis and verification
3.- Optimization of design (situation and size of buffers, equipment selection, ...) and operation (control or scheduling)
4.- Development of adequate computer tools for the modelling, analysis and synthesis.

 
Profile: Computer Science, Electrical/Electronics Eng., Communications Eng., Mathematics, Physics

Tasks: 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.

Availability: Starting on January 2004

Salary: around 12000 EUR/year

Contact: Applicants should send their CVs and a letter of intentions before October 17th to

Prof. Laura Recalde (lrecaldeunizar [dot] es)
Departamento de Informática e Ingeniería de Sistemas
Universidad de Zaragoza
Maria de Luna 1,
50018 Zaragoza, España