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Abstract—Grid computing offers significant enhancements to our capabilities for computation, information processing and collaboration, and has exciting ambitions in many fields of endeavour. In this paper we argue that the full richness of the Grid vision, with its application in e-Science, e-Research or e-Business, requires the ‘Semantic Grid’. The Semantic Grid is an extension of the current Grid in which information and services are given well-defined meaning, better enabling computers and people to work in cooperation. To this end, we outline the requirements of the Semantic Grid, discuss the state of the art in achieving them, and identify the key research challenges in realising this vision.

High quality domain ontologies are essential for successful employment of semantic Web services. However, their acquisition is difficult and costly, thus hampering the development of this field. In this paper we report on the first stage of research that aims to develop (semi-)automatic ontology learning tools in the context of Web services that can support domain experts in the ontology building task. The goal of this first stage was to get a better understanding of the problem at hand and to determine which techniques might be feasible to use. To this end, we developed a framework for (semi-)automatic ontology learning from textual sources attached to Web services. The framework exploits the fact that these sources are expressed in a specific sublanguage, making them amenable to automatic analysis. We implement two methods in this framework, which differ in the complexity of the employed linguistic analysis. We evaluate the methods in two different domains, verifying the quality of the extracted ontologies against high quality hand-built ontologies of these domains. Our evaluation lead to a set of valuable conclusions on which further work can be based. First, it appears that our method, while tailored for the Web services context, might be applicable across different domains. Second, we concluded that deeper linguistic analysis

When describing Web services, one of the obvious aspects that needs representing is Quality of Service ” (QoS), the capability of a Web service to meet an acceptable level of service as per factors such as availability and accessibility. However too much of a focus on developing functional QoS ontologies has led to an over-emphasis on representing solely QoS metrics and units of measurement. For instance, what does round trip time actually mean? Is the round trip time of every data item measured? Is it an average, or is every nth item measured? Is it the actual time that is important or just the % of items that are beyond a certain range? Arguably existing QoS ontologies cannot readily answer many of these design questions because these questions have less to do with evaluating QoS and more to do with representing “what is quality? ” Therefore, there is an unmet need for Web services ontologies that are designed at a higher level encompassing domain independent concepts, and generally applicable beyond QoS evaluations. The MOQ set of ontologies designed from the premise that quality is “conformance to requirements ” aims to fill this need. Comprised of ontologies of requirement, measurement, traceability, and quality management systems, MOQ can be extended to encompass QoS metrics and measurement units or be designed to interoperate with existing QoS ontology. Either way MOQ use promises to ensure that ambiguity in QoS evaluations is minimized.

The GRIA project set out to make the Grid usable by industry. The GRIA middleware is based on Web Services, and designed to meet the needs of industry for security and business-to-business (B2B) service procurement and operation. It provides well-defined B2B models for accounting and QoS agreement, and proxy-free delegation to support account management and service federation. The GRIA v3 software is now being used by industry. By taking a business-oriented approach independent of the evolving Open Grid Services Architecture proposals from the Global Grid Forum, GRIA has demonstrated the need for a wider understanding of Virtual Organizations (VOs). Traditional academic VOs are persistent, resourceful and have logically centralized, membership-oriented management structures. In contrast, the GRIA experience has been that business VOs are likely to be projectfocused and have distributed, process-oriented management structures. 1.

Abstract. The power of Web Service (WS) technology lies in the fact that it establishes a common, vendor-neutral platform for integrating distributed computing applications, in intranets as well as the Internet at large. Semantic Web Services (SWSs) promise to provide solutions to the challenges associated with automated discovery, dynamic composition, enactment, and other tasks associated with managing and using service-based systems. One of the barriers to a wider adoption of SWS technology is the lack of tools for creating SWS specifications. OWL-S is one of the major SWS description languages. This paper presents an OWL-S Editor, whose objective is to allow easy, intuitive OWL-S service development and to provide a variety of special-purpose capabilities to facilitate SWS design. The editor is implemented as a plugin to the Protégé OWL ontology editor, and is being developed as open-source software. 1

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Researchers are beginning to realize the potential of web services that can use the web as a place for information publication and access as opposed to the traditional webservices paradigm that merely uses the web as a transport medium. Traditional web services can be difficult to discover, can have complex invocation APIs, and require strong coupling between communicating applications. In previous work, we presented ontology-based techniques in which users make service requests using free-form, naturallanguage-like specifications. This paper shows how we can use these ontological techniques to automatically create ontology-based web services that (1) are easy for software agents to discover because they are created based on machine-processable formalisms (ontologies), (2) have invocation APIs requiring only simple read and write operations, and (3) require no a priori agreements regarding types and data formats between communicating applications. Experiments with our prototype implementation in several domains show that our approach can effectively create web services with these characteristics. 1.

The increasing ubiquity of wireless mobile devices is promoting unprecedented levels of electronic collaboration among devices interoperating to achieve a common goal. Issues related to host interoperability are addressed partially by the principles of the service-oriented computing paradigm. However, certain technical concerns relating to predictable interactions among hosts in mobile ad hoc networks have not yet received much attention. We introduce “follow-me sessions, ” where interactions occur between a client and a service, rather than a specific service provider. A client may thus exploit several service providers during the course of its interaction with a given service. This redundancy mitigates the effects of mobility-induced disconnections, thereby facilitating reliable communication. The switching of service providers is done using a combination of strong process migration, context-sensitive binding, and location-agnostic communication protocols. This paper covers the architecture and implementation of a middleware that supports follow-me sessions and shows how this middleware mitigates issues related to proxy-based service-oriented architectures in mobile ad hoc networks. We support our claims via a technical evaluation of our approach. KEY WORDS: Mobile computing, Service-oriented computing, Software architecture, Ad hoc Networks

Abstract. This paper presents a context-driven approach that aims at supporting semantic mediation between composed Web services. Despite the widespread adoption of Web services by the IT community, innovative solutions are needed in order to overcome the challenging issue that relates to the semantic disparity of exchanged data. Indeed, there is a lack of means for interpreting these data according to the contextual requirements of each Web service. The context-driven approach suggests two steps. The first step consists of developing a model for anchoring context to data flowing between Web services. In the second step, we use this model to support the semantic mediation between Web services engaged in a composition. 1