An Algorithm for Automatic Service Composition

Telecommunication companies are struggling to provide their users with value-added services. These services are expected to be context-aware, attentive and personalized. Since it is not economically feasible to build services separately by hand for each individual user, service providers are searching for alternatives to automate service creation. The IST-SPICE project aims at developing a platform for the development and deployment of innovative value-added services. In this paper we introduce our algorithm to cope with the task of automatic composition of services. The algorithm considers that every available service is semantically annotated. Based on a user/developer service request a matching service is composed in terms of component services. The composition follows a semantic graph-based approach, on which atomic services are iteratively composed based on services' functional and non-functional properties

An Introduction to Pervasive Interface Automata

Pervasive systems are often context-dependent, component based systems in which components expose interfaces and offer one or more services. These systems may evolve in unpredictable ways, often through component replacement. We present pervasive interface automata as a formalism for modelling components and their composition. Pervasive interface automata are based on the interface automata of Henzinger et al, with several significant differences. We expand their notion of input and output actions to combinations of input, output actions, and callable methods and method calls. Whereas interfaces automata have a refinement relation, we argue the crucial relation in pervasive systems is component replacement, which must include consideration of the services offered by a component and assumptions about the environment. We illustrate pervasive interface autmotata and component replacement with a small case study of a pervasive application for sports predictions

A Service-Based Component Model: Formalism, Analysis and Mechanization

Component-Based Software Engineering (CBSE) is one of the approaches to master the development of large scale software. In this setting, the verification concern is still a challenge. The objective of our work is to provide the designer of components-based systems with the methods to assist his/her use of the components. In particular, the current work adresses the composability of components and their services. A component model is presented, based on services. An associated simple but expressive formalism is introduced; it describes the services as extended LTS and their structuring as components. The composition of components is mainly based on service composition and encapsulation. The composability of component is defined from the composability of services. To ensure the correctness of component composition, we check that an assembly is possible via the checking of the composabiblity of the linked services, and their behavioral compatibility. In order to mechanize our approach, the services and the components are translated into the MEC and LOTOS formalism. Finally the MEC and LOTOS CADP toolbox is used to perform experiments

Semantic web service composition in IRS-III: The structured approach

Semantic Web Services facilitate activities including automatic discovery and composition of Web Services. Research initiatives such as WSMO have been developing specifications for this technology. This paper describes a model for composition of Web services. The proposed model complements the WSMO orchestration in IRS-III, a framework for Semantic Web Services based on WSMO specification. We present a tool based on the above model that supports a user-guided interactive composition approach, by recommending component Web services according to the composition context

Ontology learning for semantic web services

Semantic Web Services promise automatic service discovery and composition, relying heavily on domain ontology as a core component. With large Web Service repository, manual ontology development is proving a bottleneck (with associated expense and likely errors) to the realisation of a semantic Web of services. Providing the appropriate tools that assist in and automate ontology development is essential for a dynamic service vision to be realised. As a statement of research-in-progress, this paper proposes combining different ontology learning paradigms in Web Services domain, highlighting the need for further research that accommodates the variation in Web Service descriptive and operational sources. A research agenda is proposed that recognises this variation in artefacts as they are selected, pre-processed and analyzed by ontology learning techniques

Using policies to manage composite Web services

Mapping guidelines for a Web service\u27s behavior can ensure an individual Web service\u27s smooth engagement on a composite Web service, which are combinations of Web services. Developing a composite Web service requires a specification that shows elements such as the component Web services\u27 execution order, the data dependencies among the component Web services. The developers and deployers can use the policies defined for Web services composition to manage Web services at both high and low levels. Adopting policies also introduces the possibility of changing Web services\u27 behavior without altering a composition specification. The Web service deployers can continuously adjust multiple aspects such as Web services\u27 conflict-resolution mechanisms to accommodate variations in the environment

Automated Negotiation Among Web Services

Software as a service is well accepted software deployment and distribution model that is grown exponentially in the last few years. One of the biggest benefits of SaaS is the automated composition of these services in a composite system. It allows users to automatically find and bind these services, as to maximize the productivity of their composed systems, meeting both functional and non-functional requirements. In this paper we present a framework for modeling the dependency relationship of different Quality of Service parameters of a component service. Our proposed approach considers the different invocation patterns of component services in the system and models the dependency relationship for optimum values of these QoS parameters. We present a service composition framework that models the dependency relations ship among component services and uses the global QoS for service selection

Considerations of service assembly based on the analysis of data flows between services

Service composition research mostly focuses on the dynamic (workflow) aspects of compositions. In this paper we consider the static component of service composition and focus on analyzing the data flows between services within a composition. We argue that compatibility of service interfaces is a necessary precondition for service composability, and we show that data flow analysis can be applied to the problem of service composition design to identify compatible service interfaces and to minimize data coupling between services. © 2008 IEEE