Project : popart
Section: Scientific Foundations
Main Research Directions
We intend to exploit our knowledge of formal techniques and their use, and of control theory, according to aspects of the definition of fundamental tools, and applications.
The integration of formal methods in an automated process of generation/compilation is founded on the formal modeling of the considered mechanisms. This modeling is the base for the automation, which operates on models well-suited for their efficient exploitation, by analysis and synthesis techniques that are difficult to use by end-users.
The creation of easily usable models aims at giving the user the role rather of a pilot than of a mechanic, i.e., to offer her/him pre-defined functionalities which respond to concrete demands, for example in the generation of fault-tolerant or distributed executives, by the intermediary use of dedicated environments and languages.
The proposal of validated models with respect to their faithful representation of the application domain is done through case studies in collaboration with our partners, where the typical multidisciplinarity of questions across control theory and computer science is exploited.
The overall consistency of our approach comes from the fact that the main research directions address, under different aspects, the specification and generation of safe real-time control executives based on formal models.
We explore this field by linking, on the one hand, the techniques we use, with on the other hand, the functionalities we want to offer. We are interested in questions concerning:
Dedicated languages and models for automatic control which are the interface between the techniques we develop and the end-users on the one hand, and the designers of formal models on the other hand.
Compositional modeling and analysis which aim at deriving crucial system properties from component properties, without the need to actually build and check the global system.
Implementations of synchronous programs
can be tackled differently depending on the execution platform. Our approach is to obtain, by compilation (thus automatically), founded on a formal model of the program to be implemented:
the distribution on a multiprocessor architecture, with code partitioning according to directives, and insertion of the necessary communication actions to ensure the coherence of control, in a way that is guaranteed to be correct with respect to the original specification, and optimized;
fault-tolerance by replication of computations on a multiprocessor architecture, and scheduling of computations according to the faults to be tolerated.
where the interaction of the very nature of the control we consider, with its real-time implementation can be tackled in two ways:
scheduling for regulation where the scheduling scheme and parameters are designed to capture the control system requirements and improve the quality of the implemented controller;
regulation for scheduling where the latter is made adaptive and is dynamically controlled by using techniques from control theory.
Automatic generation of correct controllers
multi-mode multi-tasking systems where the management of interactions (exclusions, optimization of cost or quality criteria...) is obtained by synthesis ,
a locally imperative, globally declarative language whose compilation comprises a phase of discrete controller synthesis.