This volume contains the proceedings of FOCLASA 2014, the 13th International Workshop on the Foundations of Coordination Languages and Self-Adaptive Systems. FOCLASA 2014 was held in Rome, Italy, on September 9, 2014 as a satellite event of CONCUR 20
14, the 25th International Conference on Concurrency Theory. Modern software systems are distributed, concurrent, mobile, and often involve composition of heterogeneous components and stand-alone services. Service coordination and self-adaptation constitute the core characteristics of distributed and service-oriented systems. Coordination languages and formal approaches to modelling and reasoning about self-adaptive behaviour help to simplify the development of complex distributed service-based systems, enable functional correctness proofs and improve reusability and maintainability of such systems. The goal of the FOCLASA workshop is to put together researchers and practitioners of the aforementioned fields, to share and identify common problems, and to devise general solutions in the context of coordination languages and self-adaptive systems.
Wegner describes coordination as constrained interaction. We take this approach literally and define a coordination model based on interaction constraints and partial, iterative and interactive constraint satisfaction. Our model captures behaviour de
scribed in terms of synchronisation and data flow constraints, plus various modes of interaction with the outside world provided by external constraint symbols, on-the-fly constraint generation, and coordination variables. Underlying our approach is an engine performing (partial) constraint satisfaction of the sets of constraints. Our model extends previous work on three counts: firstly, a more advanced notion of external interaction is offered; secondly, our approach enables local satisfaction of constraints with appropriate partial solutions, avoiding global synchronisation over the entire constraints set; and, as a consequence, constraint satisfaction can finally occur concurrently, and multiple parts of a set of constraints can be solved and interact with the outside world in an asynchronous manner, unless synchronisation is required by the constraints. This paper describes the underlying logic, which enables a notion of local solution, and relates this logic to the more global approach of our previous work based on classical logic.
