Section: Overall Objectives

Objectives of the team

The goal of the TRIO team is to provide a set of techniques and methods that can be applied to design, validate and dimension real time distributed applications. In order to tackle this problem as a whole, our work is structured along two complementary points of view:

• specification of real-time on-line mechanisms (protocols, schedulers, middleware) offering services to the application with a quality of service that ensures the satisfaction of real time constraints; this includes fault detection, fault recovery and fault tolerance,

• modeling, analysis and evaluation of real time distributed systems for the verification of temporal properties and the optimisation of distributed deployment.

Furthermore, we continue to study the modeling process of real time distributed applications that allows the description of both functional and non-functional aspects of these applications and therefore a formal use of these models for quantitative evaluation and optimal scaling.

The problems to solve are mainly due to three particularities of the targeted applications:

• They are discrete event systems with temporal characteristics (temporal performances of hardware support, temporal properties); this increases the complexity of their modeling and of their analysis. Hence a part of our research objectives is to master this complexity while achieving a satisfactory trade-off between the accuracy of a model and its ability to be analyzed.

• A second aspect is the environment of these systems that can be the cause of perturbations. We need to take into account the impact of an uncertain environment (for example, the impact of electro-magnetic perturbations on a hardware support) on the required properties. Therefore we have to develop probabilistic approaches.

• Finally, the main characteristic of our work is based on the fact that we consider the performances of the hardware support. Consequently, the time that we manipulate is a physical (continuous) time and the studied systems are event driven timed systems.

These above mentioned main directions contribute to cover the full spectrum from formal modeling and evaluation of real time distributed systems up to their use in industrial problems.