Basic Observables for a Calculus for Global Computing

Abstract

We develop the semantic theory of a foundational language for modelling applications over global computers whose interconnection structure can be explicitly manipulated. Together with process distribution, process mobility and remote asynchronous communication through distributed data repositories, the language provides constructs for explicitly modelling inter-node connections and for dynamically activating and deactivating them. For the proposed language, we define natural notions of extensional observations and study their closure under operational reductions and/or language contexts to obtain barbed congruence and may testing equivalence. For such equivalences, we provide alternative characterizations in terms of a labelled bisimulation and a trace equivalence that can be used for actual proofs. We discuss how the language and its theory can be extended to include more sophisticated features that enable a finer control on the activation of connections. To asses practical usability of the semantic theory, we model a scenario for communications between mobile devices and use the introduced proof techniques to analyze it and verify some relevant properties. * This paper is an extended and revised version of [15] and was mainly written when the second author was a PhD student in Florence.

An Analysis of Formal Languages for Dynamic Adaptation

“…Localities are treated as first-class elements and can be dynamically created and communicated. Communication is effected via distributed repositories and remote operations [18], [19]. DA in KLAIM can therefore be modelled as mobile components being dynamically created and their communication links updated accordingly.…”

Bigraphical Models of Context-Aware Systems

“…The naive model of the previous section shares an important characteristic with recent proposals of formal models for context-aware computation [4,8,25] that comprise agents and contexts only: These models take the agent's ability to determine what is the present context as given. We contend that for some systems, it is natural to model not only the actual context but also the agent's representation of the actual context.…”

“…The dynamics of P state that if there is a job and a known, idle PCLprinter, the proxy may activate this printer (5); that if there is a job, no known PCL-printer, and an idle raw-printer, the context may activate that printer (6); and finally, that the proxy may discover a previously unknown printer (7,8).…”

Pattern Matching over a Dynamic Network of Tuple Spaces

“…In [7], we developed the behavioural theory of a language derived from µK by introducing explicit inter-node connections and process actions to dynamically change them. The syntax of the resulting calculus, that is called K (topological K), can be obtained by adding the following productions to those in Table 1:…”