The overall dependability of an interactive system is one of its weakest components, which is usually its user interface. The presented approach integrates techniques from the dependable computing field and elements of the user-centered design. Risk analysis and fault-tolerance techniques are used in combination with task analysis and modeling to describe and analyze the impact of system faults on human activities and the impact of human deviation or errors on system performance and overall mission performance. A technique for systematic analysis of human errors, effects, and criticality (HEECA) is proposed. It is inspired and adapted from the Failure Mode, Effects, and Criticality Analysis technique. The key points of the approach are: 1) the HEECA technique combining a systematic analysis of the effects of system faults and of human errors; and 2) a task modeling notation to describe and to assess the impact of system faults and human errors on operators' activities and system performance. These key points are illustrated on an example extracted from a case study of the space domain. It demonstrates the feasibility of this approach as well as its benefits in terms of identifying opportunities for redesigning the system, redesigning the operations, and for modifying operators' training.

This paper addresses an aircraft mission operational reliability as resulting from component failures, environment changes, and maintenance facilities offered at the various stops involved in the mission. We will show how the on-line assessment of operational reliability will help adjust an aircraft mission, in case of major changes to equipment availability during the mission. The assessment is made possible thanks to the building and validation of a generic dependability model that is easily i) processed for the assignment of an initial mission, and ii) updated during mission accomplishment, following the occurrence of some specific major events. The generic model can be built as early as the design phase, by engineers who are specialist in dependability assessment, based on stochastic processes. Model update and processing, during aircraft operation, can be achieved by operators who are not necessarily familiar with stochastic processes in the way that they are being applied in this research. We will present examples of results that show the valuable role of operational dependability re-assessment during aircraft mission.

This paper presents an approach to automate test generation from a formal specification and a set of functional test objectives while taking into account coverage constraints at the specification level. We use existing test generation techniques and tools, our contribution is on the methodological side. We define an innovative approach adapted to the industrial domain and its constraints

This paper describes the prototype of a software environment that was devised for helping the formal validation of user interfaces systems. The paper suggests an approach to include such formal operations in the design process. An abstract and formal representation of the user interface system is produced to perform formal verifications on it. The paper explains why the user interface system can be modelled properly by a dataflow system and how this model can be expressed by using equations of flows in the language Lustre. It describes then some main tools of the environment.