56,686 research outputs found

    Engineering Secure Adaptable Web Services Compositions

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    Service-oriented architecture defines a paradigm for building applications by assembling autonomous components such as web services to create web service compositions. Web services are executed in complex contexts where unforeseen events may compromise the security of the web services composition. If such compositions perform critical functions, prompt action may be required as new security threats may arise at runtime. Manual interventions may not be ideal or feasible. To automatically decide on valid security changes to make at runtime, the composition needs to make use of current security context information. Such security changes are referred to as dynamic adaptation. This research proposes a framework to develop web services compositions that can dynamically adapt to maintain the same level of security when unforeseen security events occur at runtime. The framework is supported by mechanisms that map revised security requirements arising at runtime to a new security configuration plan that is used to adapt the web services composition

    Development Of A Cloud Computing Application For Water Resources Modelling And Optimization Based On Open Source Software

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    Cloud computing is the latest advancement in Information and Communication Technology (ICT) that provides computing as a service or delivers computation, software, data access, storage service without end-user knowledge of the physical location and system configuration. Cloud computing, service oriented architecture and web geographic information systems are new technologies for development of the cloud computing application for water resources modelling and optimization. The cloud application is deployed and tested in a distributed computer environment running on three virtual machines (VMs). The cloud application has five web services for: (1) spatial data infrastructure – 1 (SDI), (2) SDI – 2, (3) support for water resources modelling (4) water resources optimization and 5) user authentication. The cloud application is developed using several programming languages (PHP, Ajax, Java, and JavaScript), libraries (OpenLayers and JQuery) and open-source software components (GeoServer, PostgreSQL and PostGIS) and OGC standards (WMS, WFS and WFT-T). The web services for support of water resources modelling and user authentication are deployed on Amazon Web Services and are communicating using WFS with the two SDI web services. The two SDI web services are working on the two separate VMs providing geospatial data and services. The fourth web service is deployed on a separate VM because of the expected large computational requirements. The cloud application is scalable, interoperable, creates a real time multi-user collaboration platform. All code and components used are open source. The cloud application was tested with concurrent multiple users. The performance, security and utilization of the distributed computer environment are monitored and analysed together with the users’ experience and satisfaction. The applicability of the presented solution and its future are elaborated

    Web based system architecture for long pulse remote experimentation

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    Remote experimentation (RE) methods will be essential in next generation fusion devices. Requirements for long pulse RE will be: on-line data visualization, on-line data acquisition processes monitoring and on-line data acquisition systems interactions (start, stop or set-up modifications). Note that these methods are not oriented to real-time control of fusion plant devices. INDRA Sistemas S.A., CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas) and UPM (Universidad Politécnica de Madrid) have designed a specific software architecture for these purposes. The architecture can be supported on the BeansNet platform, whose integration with an application server provides an adequate solution to the requirements. BeansNet is a JINI based framework developed by INDRA, which makes easy the implementation of a remote experimentation model based on a Service Oriented Architecture. The new software architecture has been designed on the basis of the experience acquired in the development of an upgrade of the TJ-II remote experimentation system

    Two ways to Grid: the contribution of Open Grid Services Architecture (OGSA) mechanisms to service-centric and resource-centric lifecycles

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    Service Oriented Architectures (SOAs) support service lifecycle tasks, including Development, Deployment, Discovery and Use. We observe that there are two disparate ways to use Grid SOAs such as the Open Grid Services Architecture (OGSA) as exemplified in the Globus Toolkit (GT3/4). One is a traditional enterprise SOA use where end-user services are developed, deployed and resourced behind firewalls, for use by external consumers: a service-centric (or ‘first-order’) approach. The other supports end-user development, deployment, and resourcing of applications across organizations via the use of execution and resource management services: A Resource-centric (or ‘second-order’) approach. We analyze and compare the two approaches using a combination of empirical experiments and an architectural evaluation methodology (scenario, mechanism, and quality attributes) to reveal common and distinct strengths and weaknesses. The impact of potential improvements (which are likely to be manifested by GT4) is estimated, and opportunities for alternative architectures and technologies explored. We conclude by investigating if the two approaches can be converged or combined, and if they are compatible on shared resources

    Aligning a Service Provisioning Model of a Service-Oriented System with the ITIL v.3 Life Cycle

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    Bringing together the ICT and the business layer of a service-oriented system (SoS) remains a great challenge. Few papers tackle the management of SoS from the business and organizational point of view. One solution is to use the well-known ITIL v.3 framework. The latter enables to transform the organization into a service-oriented organizational which focuses on the value provided to the service customers. In this paper, we align the steps of the service provisioning model with the ITIL v.3 processes. The alignment proposed should help organizations and IT teams to integrate their ICT layer, represented by the SoS, and their business layer, represented by ITIL v.3. One main advantage of this combined use of ITIL and a SoS is the full service orientation of the company.Comment: This document is the technical work of a conference paper submitted to the International Conference on Exploring Service Science 1.5 (IESS 2015

    Quality-aware model-driven service engineering

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    Service engineering and service-oriented architecture as an integration and platform technology is a recent approach to software systems integration. Quality aspects ranging from interoperability to maintainability to performance are of central importance for the integration of heterogeneous, distributed service-based systems. Architecture models can substantially influence quality attributes of the implemented software systems. Besides the benefits of explicit architectures on maintainability and reuse, architectural constraints such as styles, reference architectures and architectural patterns can influence observable software properties such as performance. Empirical performance evaluation is a process of measuring and evaluating the performance of implemented software. We present an approach for addressing the quality of services and service-based systems at the model-level in the context of model-driven service engineering. The focus on architecture-level models is a consequence of the black-box character of services
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