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    • Publications

    2001

    • Marti, P., Lanzi, P., Pucci, F.,

      Evaluating safety and usability of ATM systems.
      In Proceedings of the 4th International seminar on ATM R&D Seminar, FAA and Eurocontrol, 3-7 December 2001, Santa Fe, NM, USA.

      show abstract

      In the paper we present methodologies and results of validation carried out within the ITI project, aninnovative user interface for the En-Route and Approach Controller Working Positions for the new Ciampino ACC. The project developed as a cooperationbetween the Italian National AdministrationENAV S.p.A. (Ente Nazionale Assistenza al Volo) andthe Eurocontrol Experimental Centre (Bretigny,France). The evaluation was articulated along twodimensions, usability and safety, using a set ofdifferent methodologies. The assessment was based onthe idea that critical situations are not due only to theavailability of a certain information during the taskexecution but to the way in which differentcomponents in the process (software applications, organisational and cultural aspects, the physical layout,human operators) are balanced and interact to avoid or provoke breakdowns in the activity. The validationmethodology we adopted allows to pro-actively assess which aspects of the system may impair or enhancesafety after the introduction of new artefacts in the work setting. 

    • Pasquini A., Pistolesi G., Rizzo A.,

      Reliability Analysis of Systems Based on Software and Human Resources.
      IEEE Transactions in Reliability, December 2001.show abstract

      Safety-critical systems require an assessment activity to verify that they are able to perform their functions in specified use environments. This activity would benefit from evaluation methodologies that consider these systems as a whole and not as the simple sum of their parts. Indeed, analysis of accidents involving such systems as shown that they are rarely due to the simple failure of one from their components. Accidents are the outcome of a composite causal scenario where human, software and hardware failures combine in a complex pattern. On the contrary, dependability analysis and evaluation of safety critical systems are based on techniques and methodologies that concern human and computer separately, and whose results can hardly be integrated. The analogies between the processes of: (1) software reliability growth due to testing and the related fault removal; (2) improvement of man-machine interface due to preliminary operative feedback; (3) improvement of the operator performances due to his learning activity; suggest an effort for a common evaluation approach. Only the first one of these processes is currently modeled using mathematical methods. This paper considers extending these methods to study the reliability growth process of other system components, i.e. the operator and the man-machine interface. To study the feasibility of the approach, the paper analyses the results of an experiment in which the reliability of a system is evaluated using trend analysis. The evaluation concerns: the graphic man-machine interface and the operators, and could easily be extended to the software control system.