Requirements-Driven Adaptation of Choreographed Interactions

Electronic services are emerging as the de-facto enabler of interaction interoperability across organization boundaries. Cross-organizational interactions are often “choreographed”, i.e. specified by a messaging protocol from a global point of view independent of the local view of each interacting organization. Local requirements motivating an interaction as well as the global contextual requirements governing the interaction inevitably evolve over time, requiring adaptation of the corresponding interaction protocol. Adaptation of an interaction protocol must ensure the satisfaction of both sets of interaction requirements while maintaining consistency between the global view and the local views of an interaction specification. Such adaptation is not possible with the current state-of-the-art representations of choreographed interactions, as they capture only operational messaging specifications detached from both local organizational requirements as well as global contextual requirements. This thesis presents three novel contributions that tackle adaptation of choreographed interaction protocols: an automated technique for deriving an interaction protocol from requirements, a formalization of consistency between local and global views, and a framework for guiding the adaptation of a choreographed interaction. A choreographed interaction is specified using models of organizational requirements motivating the interaction. We employ the formal semantics embedded in requirements models to automatically derive an interaction protocol. We propose a framework for relating the global and local views of interaction specification and maintaining consistency between them. We develop a metamodel for interaction specification, from which we enumerate adaptation operations. We build a catalogue that provides guidance on performing each operation and propagating changes between the global and local views. These contributions are evaluated using examples from the literature as well as a real-world case study

WSMO-Lite: lowering the semantic web services barrier with modular and light-weight annotations

Services are an increasingly important part of the Web, and they are a necessary component of the semantic Web. Semantic Web services (SWS) are a research effort towards automation of the use of Web services, enhancing existing SOA capabilities with intelligent and automated integration. We have introduced WSMO-Lite, a lightweight service ontology intended for semantic annotations of the Web Service Description Language WSDL. In contrast to preceding SWS frameworks such as OWL-S and WSMO, WSMO-Lite simplifies the semantic descriptions and enables bottom-up semantic annotation of Web services, but very importantly, it also relaxes the requirements on completeness of semantic descriptions, which enables building incremental layers of semantics on top of existing service descriptions. In this work, we describe various useful subsets of the extent of semantic annotation on Web services with respect to the requirements of SWS automation tasks; and we detail the means of validating SWS descriptions with flexible levels of strictness

On the Reuse of SOA Components on Business Process Analysis Stages

In 2005 four German universities created a research program to improve and standardize its administration processes. Therefore, reams of processes have been analyzed and core functions identified. Automatable core functions have been afterwards implemented as webservices using the Service-oriented architecture (SOA) paradigm. For reasons of reuse these web-services have been documented using a service catalogue. However, a real advantage of SOA does not evolve until complex business services become configurable on business level. Thereby, the problem arises to make the meaning of the services understandable to non-IT employees, like business analysts. In this paper, we introduce a framework for building up a service catalogue addressing business analysts instead of IT engineers. Therefore, we discuss the composition of webservices to more complex business components. These components are described on an ITlevel addressing the catalogue manager, but contain also non-formal information for business analysts. Thus, the redesign of the universities processes can be supported now, using web-services encapsulated by business components. Our findings can help to increase the usage and acceptance of web-services on a business process level

A perspective on service orchestration

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

Flexible coordination techniques for dynamic cloud service collaboration

The provision of individual, but also composed services is central in cloud service provisioning. We describe a framework for the coordination of cloud services, based on a tuple‐space architecture which uses an ontology to describe the services. Current techniques for service collaboration offer limited scope for flexibility. They are based on statically describing and compositing services. With the open nature of the web and cloud services, the need for a more flexible, dynamic approach to service coordination becomes evident. In order to support open communities of service providers, there should be the option for these providers to offer and withdraw their services to/from the community. For this to be realised, there needs to be a degree of self‐organisation. Our techniques for coordination and service matching aim to achieve this through matching goal‐oriented service requests with providers that advertise their offerings dynamically. Scalability of the solution is a particular concern that will be evaluated in detail

Web service composition: A survey of techniques and tools

Web services are a consolidated reality of the modern Web with tremendous, increasing impact on everyday computing tasks. They turned the Web into the largest, most accepted, and most vivid distributed computing platform ever. Yet, the use and integration of Web services into composite services or applications, which is a highly sensible and conceptually non-trivial task, is still not unleashing its full magnitude of power. A consolidated analysis framework that advances the fundamental understanding of Web service composition building blocks in terms of concepts, models, languages, productivity support techniques, and tools is required. This framework is necessary to enable effective exploration, understanding, assessing, comparing, and selecting service composition models, languages, techniques, platforms, and tools. This article establishes such a framework and reviews the state of the art in service composition from an unprecedented, holistic perspective