The authors are interested in mapping hard real-time applications on distributed heterogeneous architectures. An application is modeled as a set of tasks, and they consider a fixed-priority preemptive scheduling policy. They target the early design phases, when decisions have a high impact on the subsequent implementation choices. However, due to a lack of information, the early design phases are characterized by uncertainties, e.g., in the worst-case execution times (wcets), or in the functionality requirements. They model uncertainties in the wcets using the \"Percentile method\".