A cyber-physical system (CPS) has cyber (or computational) components and physical components that communicate. The Kopernic team deals with the problem of studying time properties (execution time of a program or the schedulability of communicating programs, etc.) of the cyber components of a CPS. The cyber components may have functions with different criticalities with respect to time and a solution should come with associated proofs of its appropriateness for each criticality. A solution is appropriate for a criticality level if all functions fulfill the expectations of that criticality level.
Based on their mathematical foundations, the solutions are: either non-probabilistic when all time properties are estimated and/or bounded by numerical values or probabilistic when at least one time property is estimated and/or bounded by probability distributions.
The Kopernic team proposes a system-oriented solution to the problem of studying time properties of the cyber components of a CPS. The solution is expected to be obtained by composing probabilistic and non-probabilistic approaches for these systems.
- Proposing a classification of variability factors of execution times for a program with respect to the processor features.
- Defining a compositional rule of statistical models based on Bayesian approaches for bounds on the execution times of programs.
- Building scheduling algorithms taking into account the interaction between different variability factors.
- Proving schedulability analyses for the proposed scheduling algorithms.
- Deciding the schedulability of programs communicating through predictable and non predictable networks.