A Multi-Level Model for Web Service Composition

Web services are rapidly becoming popular as a vehiclefor the design, integration, composition, and deploymentof distributed and heterogeneous software. However,while industry standards for the description, composition,and orchestration of Web services have been under discussion(and development) for quite some time already, theirconceptual underpinnings are still in their infancy. Indeed,conceptual models for service specification are rare so far,as are investigations based on them. This paper presents amulti-level service composition model that perceives servicespecification as going through several levels of abstraction,from transactional operations to the end user.Importantly, the model allows for specification of desirablecomposition properties at all levels. Different ways ofachieving these properties as well as implications of themodel are addressed.