John Christopher McCabe-Dansted

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It can be desirable to specify polices that require a system to achieve some outcome even if a certain number of failures occur. This paper proposes a logic, RoCTL*, which extends CTL* with operators from Deontic logic, and a novel operator referred to as “Robustly”. This novel operator acts as variety of path quantifier allowing us to consider paths which(More)
Nurmi (1987) investigated the relationship between voting rules by determining the frequency that two rules pick the same winner. We use statistical techniques such as hierarchical clustering and multidimensional scaling to further understand the relationships between rules. We also investigate how the relationships change when elections with Condorcet(More)
It is known that Dodgson’s rule is computationally very demanding. Tideman (1987) suggested an approximation to it but did not investigate how often his approximation selects the Dodgson winner. We show that under the Impartial Culture assumption the probability that the Tideman winner is the Dodgson winner tend to 1. However we show that the convergence of(More)
The existing pure tableau technique for satisfiability checking BCTL* [7] begins by constructing all possible colours. Traditional tableaux begin with a single root node, and only construct formulae that are derived from that root. These rooted tableaux provide much better performance on most real world formulae, as they only need to construct a fraction of(More)
It is known that there is an exponential decision procedure for CTL. Given that important properties cannot be expressed in CTL, we seek a pure tableau based decision procedure (that does not rely on translations into automata) that is exponential for formulas that have only a bounded number of non-CTL properties. In this paper we present such a tableau for(More)
The logic RoCTL* is an extension of the branching time temporal logic CTL* to represent robustness of systems to transient failures such as loss of data packets. New operators are introduced dealing with obligation (where no failures occur) and robustness (where at most one additional failure occurs). The only known decision procedures for the temporal(More)