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.

Abstract
Composing and orchestrating software components is a fundamental concern in modern software engineering. This paper addresses the possibility of such orchestration being dynamic, in the sense that the structure of component's interconnection patterns can change at run-time. The envisaged approach extends previous work by the authors on the use of coalgebraic models for the specification of software connectors.

Abstract
This paper reports on the development of specific slicing techniques for functional programs and their use for the identification of possible coherent components from monolithic code. An associated tool is also introduced. This piece of research is part of a broader project on program understanding and re-engineering of legacy code supported by formal methods.

Abstract
Over the last decade, software architecture emerged as a critical issue in Software Engineering. This encompassed a shift from traditional programming towards software development based on the deployment and assembly of independent components. The specification of both the overall systems structure and the interaction patterns between their components gbecame a major concern for the working developer. Although a number of formalisms to express behaviour and to supply the indispensable calculational power to reason about designs, are available, the task of deriving architectural designs on top of popular component platforms has remained largely informal. This paper introduces a systematic approach to derive, from CCS behavioural specifications the corresponding architectural skeletons in the Microsoft. Net framework, in the form of executable C# and C? code. The prototyping process is fully supported by a specific tool developed in Haskell.

Abstract
This paper introduces a generic semantic framework for component-based development, expressed in the unified modelling language UML. The principles of a coalgebraic semantics for class, object and statechart diagrams as well as for use cases, are developed. It is also discussed how to formalize the refinement steps in the development process based upon a suitable notion of behavior refinement. In this way, a formal basis for component-based development in UML is studied, which allows the construction of more complex and specific systems from independent components. © 2005 Published by Elsevier B.V.