State robust planning

In previous work (Karagiannis et al. 2010) develop a method laying on models to assess robustness of Emergency Response Plan in industrial context. This method is based on questionnaires to assess probability of resource failure modes, organize and combine them in a Fault-Tree (FT) specific to each category (human, technical, organizational and informational). In this way plan failure scenarios can be built. Authors developed also a resource taxonomy for Emergency Response Plan to build patterns of Fault-Tree. A limit of this work is that it considered for model elements (both resource and function) only two binary states and so does not take into account partial failures of these elements, specifically function element. As it can be noticed in real world many elements of a system may have more than two possible states of failure. Moreover, these states may be qualified by a real value (not only 0 and 1). 

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