In this presentation we will report on a number of projects where we have successfully applied the ASM methodology to provide abstract models for a number of problems that are commonly found in Service Oriented Architectures (SOAs). In particular, we will provide solutions for the following topics: (1) service behaviour mediation, (2) service discovery, and (3) service composition. Introduction. Service Oriented Architecture (SOA) serve as an architectural blueprint for designing flexible information systems. SOAs are built from au- tonomous functional entities, services, which inter-operate through well-defined, message-based interfaces that abstract from both programming languages and implementation platforms. The most prominent incarnation of this architectural blueprint is based on the technical specification set defined by the World Wide Web Consortium (W3C) where services expose their functionality as so-called Web1 services. The corre- sponding W3C technical report on the Web Services Architecture (7) describes a basic engagement model that identifies, among others, the following three fundamental entities: the service requester invoking functionality from a service provider through message exchanges. The definition of these message exchanges has been published and thus can be retrieved through a public service discovery service.
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"Though they provide a definition for job scheduling, they do not detail brokering steps and mechanisms at different levels. Altenhofen et al. investigated Service Oriented Architectures in , more specifically service discovery, mediation and composition. These components have some similar functionalities but this work is more focused on a unified, higher level service framework, and do not explore resource manager components. "
[Show abstract][Hide abstract] ABSTRACT: Coordination in distributed environments, like Grids, involves selecting the most appropriate services, resources or compositions to carry out the planned activities. Such functionalities appear at various levels of the infrastructure and in various means forming a blurry domain, where it is hard to see how the participating components are related and what their relevant properties are. In this paper we focus on a subset of these problems: resource brokering in Grid middleware. This paper aims at establishing a semantical model for brokering and related activities by defining brokering agents at three levels of the Grid middleware for resource, host and broker selection. The main contribution of this paper is the definition and decomposition of different brokering components in Grids by providing a formal model using Abstract State Machines.
[Show abstract][Hide abstract] ABSTRACT: Formal design methods, that might serve as a basis for specifying and analyzing abstract models of service orchestrations, are needed to complement the wide range of domain-specific languages (mainly based on graphical notations) that are currently being defined for engineering service-oriented systems. This paper presents a formal and executable semantic framework for UML4SOA models of service-oriented systems. The UML4SOA language is a UML profile developed in the EU SENSORIA project for modeling services behavior focusing on service orchestration aspects. We complement the graphical model of a service orchestration scenario with a formal description that is suitable for rigorous execution-platform-independent analysis. We map the behavioral primitives of UML4SOA activity diagrams into a particular class of Abstract State Machines (ASMs) able to model notions of service interactions and orchestrations.
[Show abstract][Hide abstract] ABSTRACT: This book constitutes the refereed proceedings of the First International Conference of Abstract State Machines, B and Z, ABZ 2008, held in London, UK, in September 2008. The conference simultaneously incorporated the 15th International ASM Workshop, the 17th International Conference of Z Users and the 8th International Conference on the B Method. The 44 revised full papers presented together with 4 invited contributions were carefully reviewed and selected from numerous submissions. The conference fosters the cross-fertilization of three rigorous methods for the design and analysis of hardware and software systems - both in academia and industry - namely Abstract State Machines, B, and Z. Covering a wide range of research spanning from theoretical and methodological foundations to tool support and practical applications, the contributions are organized in topical sections on abstract state machines, B papers, Z papers, ABZ short papers, and the papers of the Verified Software Repository Network (VSR-net) workshop.