Abstract
This paper characterises refinement of state-based software components modelled as pointed coalgebras for some Set endofunctors. The proposed characterisation is parametric on a specification of the underlying behaviour model introduced as a strong monad. This provides a basis to reason about (and transform) state-based software designs. In particular, it is shown how refinement can be applied to the development of the inequational subset of a calculus of generic software components.

Abstract
Current software development often relies on non-trivial coordination logic for combining autonomous services, eventually running on different platforms. As a rule, however, such a coordination layer is strongly woven within the application at source code level. Therefore, its precise identification becomes a major methodological (and technical) problem and a challenge to any program understanding or refactoring process. The approach introduced in this paper resorts to slicing techniques to extract coordination data from source code. Such data are captured in a specific dependency graph structure from which a coordination model can be recovered either in the form of an ORC specification or as a collection of code fragments corresponding to the identification of typical coordination patterns in the system. Tool support is also discussed.

Abstract
Service-oriented computing is an emerging paradigm with increasing impact on the way modern software systems are designed and developed. Services are autonomous, loosely coupled and heterogeneous computational entities able to cooperate to achieve common goals. This paper introduces a model for service orchestration, which combines a exogenous coordination model, with services' interfaces annotated with behavioural patterns specified in a process algebra which is parametric on the interaction discipline. The coordination model is a variant of REO for which a new semantic model is proposed. (C) 2009 Published by Elsevier B.V.

Abstract
Even though concurrent programming has been a hot topic of discussion in Computer Science for the past 30 years, the community has yet to settle on a, or a few standard approaches to implement concurrent programs. But as more and more cores inhabit our CPUs and more and more services are made available on the web the problem of coordinating different tasks becomes increasingly relevant. The present paper addresses this problem with an implementation of the orchestration language Orc as a domain specific language in Haskell. Orc was, therefore, realized as a combinator library using the lightweight threads and the communication and synchronization primitives of the Concurrent Haskell library. With this implementation it becomes possible to create orchestrations that re-use existing Haskell code and, conversely, re-use orchestrations inside other Haskell programs. The complexity inherent to distributed computation, entails the need for the classification of efficient, reusable, concurrent programming patterns. The paper discusses how the calculus of recursive schemes used in the derivation of functional programs, scales up to a distributed setting. It is shown, in particular, how to parallelize the entire class of binary tree hylomorphisms.

Abstract
Labelled transition systems admit different but equivalent characterizations either as relational structures or coalgebras for the powerset functor, each of them with their own merits. Notions of simulation and bisimulation, for example, are expressed in the pointfree relational calculus in a very concise and precise way. On the other hand, the coalgebraic perspective regards processes as inhabitants of a final universe and allows for an intuitive definition of the semantics of process' combinators. This paper is an exercise on such a dual characterisation. In particular, it discusses how a notion of weak bisimilarity can be lifted from the relational to the coalgebraic level, to become an effective reasoning tool on coinductively defined process algebras.

Abstract
The quest for sound foundations for the orchestration of web services is still open. To a great extent its relevance comes from the possibility of defining formal semantics for new language standards (like BPEL4WS or WS-CDL) in this emerging and challenging technology. As a step in that direction, this paper resorts to a notion of configuration, developed by the authors in the context of a Reo-like exogenous coordination model for software components, to formally express service orchestration. The latter is regarded as involving both the architectural assembly of independent services and the description of their interactions.