6,661 research outputs found

    A middleware framework for constraint-based deployment and autonomic management of distributed applications

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    Submitted to Middleware 04 Funded by the EPSRC UK grant GR/S44501 "Secure LocationIndependent Autonomic Storage Architectures"We propose a middleware framework for deployment and subsequent autonomic management of component-based distributed applications. An initial deployment goal is specified using a declarative constraint language, expressing constraints over aspects such as component-host mappings and component interconnection topology. A constraint solver is used to find a configuration that satisfies the goal, and the configuration is deployed automatically. The deployed application is instrumented to allow subsequent autonomic management. If, during execution, the manager detects that the original goal is no longer being met, the satisfy/deploy process can be repeated automatically in order to generate a revised deployment that does meet the goal

    An automated ETL for online datasets

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    While using online datasets for machine learning is commonplace today, the quality of these datasets impacts on the performance of prediction algorithms. One method for improving the semantics of new data sources is to map these sources to a common data model or ontology. While semantic and structural heterogeneities must still be resolved, this provides a well established approach to providing clean datasets, suitable for machine learning and analysis. However, when there is a requirement for a close to real time usage of online data, a method for dynamic Extract-Transform-Load of new sources data must be developed. In this work, we present a framework for integrating online and enterprise data sources, in close to real time, to provide datasets for machine learning and predictive algorithms. An exhaustive evaluation compares a human built data transformation process with our system’s machine generated ETL process, with very favourable results, illustrating the value and impact of an automated approach

    A Middleware Framework for Constraint-Based Deployment and Autonomic Management of Distributed Applications

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    We propose a middleware framework for deployment and subsequent autonomic management of component-based distributed applications. An initial deployment goal is specified using a declarative constraint language, expressing constraints over aspects such as component-host mappings and component interconnection topology. A constraint solver is used to find a configuration that satisfies the goal, and the configuration is deployed automatically. The deployed application is instrumented to allow subsequent autonomic management. If, during execution, the manager detects that the original goal is no longer being met, the satisfy/deploy process can be repeated automatically in order to generate a revised deployment that does meet the goal.Comment: Submitted to Middleware 0

    An automated ETL for online datasets

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    While using online datasets for machine learning is commonplace today, the quality of these datasets impacts on the performance of prediction algorithms. One method for improving the semantics of new data sources is to map these sources to a common data model or ontology. While semantic and structural heterogeneities must still be resolved, this provides a well established approach to providing clean datasets, suitable for machine learning and analysis. However, when there is a requirement for a close to real time usage of online data, a method for dynamic Extract-Transform-Load of new sources data must be developed. In this work, we present a framework for integrating online and enterprise data sources, in close to real time, to provide datasets for machine learning and predictive algorithms. An exhaustive evaluation compares a human built data transformation process with our system’s machine generated ETL process, with very favourable results, illustrating the value and impact of an automated approach

    Demonstration of sustained and useful converter responses during balanced and unbalanced faults in microgrids

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    In large power grids where converter penetration is presently low and the network impedance is predominantly reactive, the required response from converters during faults is presently specified by phrases such as “maximum reactive output”. However, in marine and aero power systems most faults are unbalanced, the network impedance is resistive, and converter penetration may be high. Therefore a balanced reactive fault current response to an unbalanced fault may lead to over-voltages or over/under frequency events. Instead, this paper presents a method of controlling the converter as a balanced voltage source behind a reactance, thereby emulating the fault response of a synchronous generator (SG) as closely as possible. In this mode there is a risk of converter destruction due to overcurrent. A new way of preventing destruction but still providing fault performance as close to a SG as possible is presented. Demonstrations are presented of simulations and laboratory testing at the 10kVA 400V scale, with balanced and unbalanced faults. Currents can be limited to about 1.5pu while still providing appropriate unbalanced fault response within a resistive network

    A Flexible and Secure Deployment Framework for Distributed Applications

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    This paper describes an implemented system which is designed to support the deployment of applications offering distributed services, comprising a number of distributed components. This is achieved by creating high level placement and topology descriptions which drive tools that deploy applications consisting of components running on multiple hosts. The system addresses issues of heterogeneity by providing abstractions over host-specific attributes yielding a homogeneous run-time environment into which components may be deployed. The run-time environments provide secure binding mechanisms that permit deployed components to bind to stored data and services on the hosts on which they are running.Comment: 2nd International Working Conference on Component Deployment (CD 2004), Edinburgh, Scotlan

    Utilising Facebook: immersing Generation-Y students into first year university

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    This case study explores the use of the online social networking site, Facebook, in helping immerse first year students into university culture, by furthering the development of academic and social relationships between peers. Facebook was chosen as the host site on account of the uniform strength of its features as compared to other popular social networking sites such as MySpace and Friendster, the image-sharing site Flickr, and the open-source software Moodle. The site’s popularity ensured that many students would be familiar with its layout and operation, while the ‘group’ and ‘event’ applications enabled the creation of an accessible, easily-maintained, and highly interactive online forum. Lastly, the 24/7 availability of the site conformed with the ‘anytime, anywhere’ work attitude of Generation-Y students. 100 first year design students took part in the study, within the course Imaging Our World at the University of Adelaide. Every two weeks, students were required to submit images to an online gallery in Facebook, and to provide critiques on peers’ submissions. The gallery topics were broad in nature, and open to the student’s own interpretations, allowing for a wide range of images in each: this produced a concurrently wide range of discussions. The galleries allowed students to connect with each other in a virtual environment, and thus to develop academic relationships freed from the constraints of the classroom and their own inhibitions. Through the use of such collaborative learning, students were able to engage with their peers and develop a sense of belonging within the learning community. Discussions often evolved from formal academic critiques to informal social interactions as the students became more comfortable with each other. In summary, the study was considered to have been a success, due to Facebook’s engaging and interactive qualities, the students’ existing interest and experience with the software, and their eagerness to connect with their peers. The project will be adapted in 2009 based on the initial findings of this study and the design of course-specific Facebook applications.Joshua McCarth

    Applying constraint solving to the management of distributed applications

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    Submitted to DOA08We present our approach for deploying and managing distributed component-based applications. A Desired State Description (DSD), written in a high-level declarative language, specifies requirements for a distributed application. Our infrastructure accepts a DSD as input, and from it automatically configures and deploys the distributed application. Subsequent violations of the original requirements are detected and, where possible, automatically rectified by reconfiguration and redeployment of the necessary application components. A constraint solving tool is used to plan deployments that meet the application requirements.Postprin
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