This paper presents a conceptual framework for service modelling and refinement, called the COSMO (COnceptual Service MOdelling) framework. This framework provides concepts to model and reason about services, and to support operations, such as composition and discovery, which are performed on them at design and run-time. In particular, the framework should facilitate the use of different service description languages tailored to different service aspects, such as the behaviour of a service and the information it manipulates, or design tasks, such as modelling, analysis and implementation. The idea is that models produced by these languages can be mapped onto the concepts of the framework, thereby facilitating one to relate these models, e.g., to verify consistency. Therefore, a requirement on the framework is to provide concepts that capture all elementary and generic service properties that are relevant during the service development process. We capture these properties by analysing existing service definitions and from earlier experience. Furthermore, we want the same concepts to be applicable throughout the service development process when modelling and refining services at successive abstraction levels. The framework distinguishes three generic abstraction levels, and describes an approach to assess the conformance between the service models produced at these abstraction levels.

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This paper discusses theoretical background for the use of Z as a language for partial specification, in particular techniques for checking consistency between viewpoint specifications. The main technique used is unification, i.e. finding a (candidate) least common refinement. The corresponding notion of consistency between specifications turns out to be different from the known notions of consistency for single Z specifications. A key role is played by correspondence relations between the data types used in the various viewpoints.

The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record.

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