Les ambivalences du risque

This thesis describes a task model-based approach for developing interactive systems, where task models succeeded in supporting the various phases of the software development life cycle: from design, to verification, to evaluation. Different techniques have been used in the phases, all of them taking benefits from the expressiveness and flexibility provided by the CTT notation and the related tool.An application of the proposed approach to a case study in the Air Traffic Control domain has been illustrated in the thesis.