Reduced Dependent Ordered Binary Decision Diagrams: An Extension of ROBDDs for Dependent Variables

In this report, we presented an extension of robdds that is able to accommodate certain dependencies among their (Boolean) variables. In particular, this extension shows evidence of being applicable to evaluating the dependability (reliability, availability) of systems whose structures are representable by a Boolean function. This extension consists of three main parts. The first part is the notion of a phratry with its associated new definitions and constraints. The second part consists of the adaptation and complementation of the original rules used in the construction of robdds. The final part concerns additional custom-made steps needed to determine the functional valuations that are specific to solving measure in question.