We propose an object-oriented calculus with internal concurrency and class-based inheritance that is built upon the join calculus. Method calls, locks, and states are handled in a uniform manner, using asynchronous messages. Classes are partial message definitions that can be combined and transformed. We design operators for behavioral and synchronization inheritance. We also give a type system that statically enforces basic safety properties. Our model is compatible with the JoCaml implementation

We extend the π-calculus with polyadic synchronisation, a generalisation of the communication mechanism which allows channel names to be composite. We show that this operator embeds nicely in the theory of π-calculus, we suggest that it permits divergence-free encodings of distributed calculi, and we show that a limited form of polyadic synchronisation can be encoded weakly in π-calculus. After showing that matching cannot be derived in π-calculus, we compare the expressivity of polyadic synchronisation, mixed choice and matching. In particular we show that the degree of synchronisation of a language increases its expressive power by means of a separation result in the style of Palamidessi's result for mixed choice.

We propose an extension of the asynchronous π-calculus with a notion of random choice. We define an operational semantics which distinguishes between probabilistic choice, made internally by the process, and nondeterministic choice, made externally by an adversary scheduler. This distiction

Workpackage list .................................................................................................................... 17 9.3 Workpackage descriptions ........................................................................................................ 18 9.4 Deliverables list...................................................................................................................... 31 9.5 Project planning and time table (GANTT Chart)............................................................................ 33 9.6 Graphical presentation of project components............................................................................... 34 9.7 PROJECT MANAGEMENT............................................................................................................ 35 10. CLUSTERING..................................................................................................................................

A synchronization is a mechanism allowing two or more processes to perform actions at the same time. We study the expressive power of synchronizations gathering more and more processes simultaneously. We demonstrate the nonexistence of a uniform, fully distributed translation of Milner’s CCS with synchronizations of n + 1 processes into CCS with synchronizations of n processes that retains a “reasonable ” semantics. We then extend our study to CCS with symmetric synchronizations allowing a process to perform both inputs and outputs at the same time. We demonstrate that synchronizations containing more than three input/output items are encodable in those with three items, while there is an expressivity gap between three and two. 1.

We extend the #-calculus with polyadic synchronisation, a generalisation of the communication mechanism which allows channel names to be composite. We show that this operator embeds nicely in the theory of #-calculus, and makes it possible to derive divergence-free encodings of distributed calculi. We give a separation result between the #-calculus with polyadic synchronisation ( #) and the original calculus, in the style of an analogous result given by Palamidessi for mixed choice. We encode Local Area # showing how to control the local use of resources in #.