Section: Scientific Foundations

Fondation

In order to check for the timing behavior and the reliability of distributed systems, the TRIO team developed several techniques based on deterministic approaches ; in particular, we apply and extend analytical evaluation of worst case response times and when necessary, e.g. for large-scale communication systems as Internet based applications, we use techniques based on network calculus.

When the environment might lead to hazards (e.g. electromagnetic interferences causing transmission errors and bit-flips in memory), or when some characteristics of the system are not perfectly known or foreseeable beforehand, we model and analyze the uncertainties using stochastic models, for instance, models of the frame transmission patterns or models of the transmission errors. In the context of real time computing, we are in general much more interested by worst-case results over a given time window than by average and asymptotic results, and dedicated analyses in that area have been developed in our team over the last 10 years.

In the design of discrete event systems with hard real time constraints, the scheduling of the system’s activities is of crucial importance. This means that we have to devise scheduling policies that ensure the respect of time constraints on line and / or optimize the behavior of the system according to some other application-dependent performance criteria.

In order to foster the best quality for programs, their understanding has to be automated, or at made significantly easier. Thus, we focus on analyzing and modeling program code, program structure and program behavior, and presenting these pieces of information to the user (in our case, program designers and program developers). Modeling user interaction is to come as well.

In the design of embedded, autonomous systems, power and energy usage is of paramount importance. We thus strive to model energy usage, based on actual hardware, and derive context-aware optimizations to decrease peak power and overall energy usage.