181,414 research outputs found

    Ontologizing Lexicon Access Functions based on an LMF-based Lexicon Taxonomy

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    This paper discusses ontologization of lexicon access functions in the context of a service-oriented language infrastructure, such as the Language Grid. In such a language infrastructure, an access function to a lexical resource, embodied as an atomic Web service, plays a crucially important role in composing a composite Web service tailored to a user?s specific requirement. To facilitate the composition process involving service discovery, planning and invocation, the language infrastructure should be ontology-based; hence the ontologization of a range of lexicon functions is highly required. In a service-oriented environment, lexical resources however can be classified from a service-oriented perspective rather than from a lexicographically motivated standard. Hence to address the issue of interoperability, the taxonomy for lexical resources should be ground to principled and shared lexicon ontology. To do this, we have ontologized the standardized lexicon modeling framework LMF, and utilized it as a foundation to stipulate the service-oriented lexicon taxonomy and the corresponding ontology for lexicon access functions. This paper also examines a possible solution to fill the gap between the ontological descriptions and the actual Web service API by adopting a W3C recommendation SAWSDL, with which Web service descriptions can be linked with the domain ontology

    A middleware for service oriented computing in dynamic environments

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    Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia InformáticaThe last years have witnessed a convergence on the SOA paradigm from industrial processes enterprises (like logistics or manufacturing), using standards for data and communication. SOA promotes reusability, interoperability and loose-coupling of applications. The convergence towards SOA shows that we are leading to an infrastructure composed by several heterogeneous devices, the "Internet of Things". In this infrastructure everything can be abstracted as a service, such as household appliances, mobile devices, or industrial machinery. It is expected that this trend will continue, and as these devices interoperate in service composition, new functionalities may be discovered. Existing approaches for service composition, namely in business processes, are too bound to BPEL. Several alternatives and extensions of BPEL have been developed, but they feel more like patches than solutions. In this context SeDeUse [29] model has been proposed as an exercise to define new language constructs promoting a separation from service awareness and use. The model also relies on a middleware layer to support the execution of the application in dynamic environments. The goal of this dissertation is to instantiate the SeDeUse model in a widely used programming language in order to provide a framework for its assessment and for its future development. The work consists on implementing a concrete syntax for the model, a compilation process, and a middleware layer. The syntax contains the new language constructs that are integrated in the hosting language. The compilation process is responsible for service definition and code generation. Finally, the middleware acts as a support for the application (generated code) requests. We have seamlessly integrated SeDeUse in the Java programming language and developed a functional prototype. To assess the prototype capability, three scenarios were developed in which we demonstrated that our implementation provides a new, and simpler, approach for abstracting resources as services

    A metadata service for service oriented architectures

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    Service oriented architectures provide a modern paradigm for web services allowing seamless interoperation among network applications and supporting a flexible approach to building large complex information systems. A number of industrial standards have emerged to exploit this paradigm with the development o f the J2E E and .N E T infrastructure platforms, communication protocol SOAP, d e scription language WSDL and orchestration languages BPEL, XLANG and WSCI. At the same time the Semantic Web enables automated use of ontologies to describe web services in a machine interpretable language. To enable process composition and large scale resource integration over heterogeneous sources a new research in itiative is needed. Current initiatives have identified the role of Peer-to-Peer networks and Service Oriented Architectures to enable large scale resource communication an d integration. However this approach neglects to identify or utilise the role of Semantic Web technologies to promote greater automation and reliability using service semantics, thus a new framework is required adopting Peer-to-Peer networks, Service Oriented Architectures and Semantic Web technologies. In this context, this thesis presents a management an d storage framework for a distributed service repository over a super peer network to facilitate process composition

    Dynamic adaptation of service compositions with variability models

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    Web services run in complex contexts where arising events may compromise the quality of the whole system. Thus, it is desirable to count on autonomic mechanisms to guide the self-adaptation of service compositions according to changes in the computing infrastructure. One way to achieve this goal is by implementing variability constructs at the language level. However, this approach may become tedious, difficult to manage, and error-prone. In this paper, we propose a solution based on a semantically rich variability model to support the dynamic adaptation of service compositions. When a problematic event arises in the context, this model is leveraged for decision-making. The activation and deactivation of features in the variability model result in changes in a composition model that abstracts the underlying service composition. These changes are reflected into the service composition by adding or removing fragments of Business Process Execution Language (WS-BPEL) code, which can be deployed at runtime. In order to reach optimum adaptations, the variability model and its possible configurations are verified at design time using Constraint Programming. An evaluation demonstrates several benefits of our approach, both at design time and at runtime.This work has been developed with the support of MICINN under the project everyWare TIN2010-18011 and co-financed with ERDF.Alférez Salinas, GH.; Pelechano Ferragud, V.; Mazo, R.; Salinesi, C.; Díaz, D. (2014). Dynamic adaptation of service compositions with variability models. Journal of Systems and Software. 91:24-47. https://doi.org/10.1016/j.jss.2013.06.034S24479

    Towards the Composition of Services by End-Users

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    Nowadays, we live surrounded by heterogeneous and distributed services that are available to people anytime and anywhere. Even though these services can be used individually, it is through their synchronized and combined usage that end-users are provided with added value. However, existing solutions to service composition are not targeted at ordinary end-users. In fact, these solutions require technical knowledge to deal with the technological heterogeneity in which they are offered to the market. To this end, the paper presents a tool-supported platform that is aided by: (1) EUCalipTool, an end-user mobile tool that implements a Domain Specific Visual Language, which has been specifically designed to compose services on mobile devices; (2) a Faceted Service Registry, which plays the role of gateway between service implementations and end-users, hiding technological issues from the latter when including services in a composition; and (3) a Generation Module, which transforms end-user descriptions into BPMN specification that are interpreted by an execution infrastructure developed for that purpose

    A conceptual architecture for semantic web services development and deployment

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    Several extensions of the Web Services Framework (WSF) have been proposed. The combination with Semantic Web technologies introduces a notion of semantics, which can enhance scalability through automation. Service composition to processes is an equally important issue. Ontology technology – the core of the Semantic Web – can be the central building block of an extension endeavour. We present a conceptual architecture for ontology-based Web service development and deployment. The development of service-based software systems within the WSF is gaining increasing importance. We show how ontologies can integrate models, languages, infrastructure, and activities within this architecture to support reuse and composition of semantic Web services

    A QoS-Aware BPEL Framework for Service Selection and Composition Using QoS Properties

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    Abstract—The promise of service oriented computing, and the availability of web services in particular, promote delivery of services and creation of new services composed of existing services – service components are assembled to achieve integrated computational goals. Business organizations strive to utilize the services and to provide new service solutions and they will need appropriate tools to achieve these goals. As web and internet based services grow into clouds, inter-dependency of services and their complexity increases tremendously. The cloud ontology depicts service layers from a high-level, such as Application and Software, to a low-level, such as Infrastructure and Platform. Each component resides at one layer can be useful to others as a service. It hints the amount of complexity resulting from not only horizontal but also vertical integrations in building and deploying a composite service. Our framework tackles the complexity of the selection and composition issues with additional qualitative information to the service descriptions using Business Process Execution Language (BPEL). Engineers can use BPEL to explore design options, and have the QoS properties analyzed for the design. QoS properties of each service are annotated with our extension to Web Service Description Language (WSDL). In this paper, we describe our framework and illustrate its application to one QoS property, performance. We translate BPEL orchestration and choreography into appropriate queuing networks, and analyze the resulting model to obtain the performance properties of the composed service. Our framework is also designed to support utilizations of other QoS extensions of WSDL, adaptable business logic languages, and composition models for other QoS properties

    A look at cloud architecture interoperability through standards

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    Enabling cloud infrastructures to evolve into a transparent platform while preserving integrity raises interoperability issues. How components are connected needs to be addressed. Interoperability requires standard data models and communication encoding technologies compatible with the existing Internet infrastructure. To reduce vendor lock-in situations, cloud computing must implement universal strategies regarding standards, interoperability and portability. Open standards are of critical importance and need to be embedded into interoperability solutions. Interoperability is determined at the data level as well as the service level. Corresponding modelling standards and integration solutions shall be analysed

    Enabling IoT stream management in multi-cloud environment by orchestration

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    (c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Every-Day lives are becoming increasingly instrumented by electronic devices and any kind of computer-based (distributed) service. As a result, organizations need to analyse an enormous amounts of data in order to increase their incomings or to improve their services. Anyway, setting-up a private infrastructure to execute analytics over Big Data is still expensive. The exploitation of Cloud infrastructure in IoT Stream management is appealing because of costs reductions and potentiality of storage, network and computing resources. The Cloud can consistently reduce the cost of analysis of data from different sources, opening analytics to big storages in a multi-cloud environment. Anyway, creating and executing this kind of service is very complex since different resources have to be provisioned and coordinated depending on users' needs. Orchestration is a solution to this problem, but it requires proper languages and methodologies for automatic composition and execution. In this work we propose a methodology for composition of services used for analyses of different IoT Stream and, in general, Big Data sources: in particular an Orchestration language is reported able to describe composite services and resources in a multi-cloud environment.Peer ReviewedPostprint (author's final draft

    Aspects of Assembly and Cascaded Aspects of Assembly: Logical and Temporal Properties

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    Highly dynamic computing environments, like ubiquitous and pervasive computing environments, require frequent adaptation of applications. This has to be done in a timely fashion, and the adaptation process must be as fast as possible and mastered. Moreover the adaptation process has to ensure a consistent result when finished whereas adaptations to be implemented cannot be anticipated at design time. In this paper we present our mechanism for self-adaptation based on the aspect oriented programming paradigm called Aspect of Assembly (AAs). Using AAs: (1) the adaptations process is fast and its duration is mastered; (2) adaptations' entities are independent of each other thanks to the weaver logical merging mechanism; and (3) the high variability of the software infrastructure can be managed using a mono or multi-cycle weaving approach.Comment: 14 pages, published in International Journal of Computer Science, Volume 8, issue 4, Jul 2011, ISSN 1694-081
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