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A syntactic framework called SGSOS, for defining well-behaved Mar-kovian stochastic transition systems, is introduced by analogy to the GSOS congruence format for nondeterministic processes. Stochastic bisimilarity is guaranteed a congruence for systems defined by SGSOS rules. Associativity of parallel composition in stochastic process algebras is also(More)
In a reputation-based trust-management system, agents maintain information about the past behaviour of other agents. This information is used to guide future trust-based decisions about interaction. However, while trust management is a component in security decision-making, many existing reputation-based trust-management systems provide no formal(More)
We introduce weighted GSOS, a general syntactic framework to specify well-behaved transition systems where transitions are equipped with weights coming from a commu-tative monoid. We prove that weighted bisimilarity is a congruence on systems defined by weighted GSOS specifications. We illustrate the flexibility of the framework by instantiating it to(More)
Models for concurrency can be classified with respect to three relevant parameters: be-haviour/system, interleaving/noninterleaving, linear/branching time. When modelling a process, a choice concerning such parameters corresponds to choosing the level of abstraction of the resulting semantics. In this paper, we move a step towards a classification of models(More)
Boxed Ambients (BA) replace Mobile Ambients'ÓÔÒ capability with communication primitives acting across ambient boundaries. Expressiveness is achieved at the price of communication interferences on message reception whose resolution requires synchronisation of activities at multiple, distributed locations. We study a variant of BA aimed at controlling(More)
We exploit a notion of interface for Petri nets in order to design a set of net combinators. For such a calculus of nets, we focus on the behavioural congruences arising from four simple notions of behaviour, viz., traces, maximal traces, step, and maximal step traces, and from the corresponding four notions of bisimulation, viz., weak and weak step(More)
An intuitionistic, hybrid modal logic suitable for reasoning about distribution of resources was introduced in [14, 15]. The modalities of the logic allow us to validate properties in a particular place, in some place and in all places. We give a sound and complete Kripke semantics for the logic extended with disjunctive connectives. The extended logic can(More)
Probabilistic trust has been adopted as an approach to taking security sensitive decisions in modern global computing environments. Existing proba-bilistic trust frameworks either assume fixed behaviour for the principals or incorporate the notion of 'decay' as an ad hoc approach to cope with their dynamic behaviour. Using Hidden Markov Models (HMMs) for(More)