32 research outputs found

    Representing software usage models with stochastic automata networks

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    Organisational Size Metrics in IS Research: A Critical Survey of the Literature 1989 - 2000

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    A number of disciplines pursue research into organisations. This organisational research serves to improve knowledge regarding the interaction, behaviour and direction of humans and groups. Many of these disciplines use proprietary methods for and approaches to such research. Because Information Systems (IS) has drawn on several of these disciplines for foundation, a number of research approaches exist for examining organisations within the IS domain. Organisational size measurement, as one research approach in the IS literature, has received considerable application but little critical examination. This study examines six leading IS journals over an eleven year period in order to document and classify the metrics used for organisational size measurement in the IS research literature. The results show a large number of metrics in scholarly use, with studies offering little supportive discussion regarding the application of these metrics. The findings raise a number of issues that are out of the scope of this study: these issues merit further research

    Parallel performance prediction using lost cycles analysis

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    Monitoring Computer Systems: An Intelligent Approach

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    Monitoring modern computer systems is increasingly difficult due to their peculiar characteristics. To cope with this situation, the dissertation develops an approach to intelligent monitoring. The resulting model consists of three major designs: representing targets, controlling data collection, and autonomously refining monitoring performance. The model explores a more declarative object-oriented model by introducing virtual objects to dynamically compose abstract representations, while it treats conventional hard-wired hierarchies and predefined object classes as primitive structures. Taking the representational framework as a reasoning bed, the design for controlling mechanisms adopts default reasoning backed up with ordered constraints, so that the amount of data collected, levels of details, semantics, and resolution of observation can be appropriately controlled. The refining mechanisms classify invoked knowledge and update the classified knowledge in terms of the feedback from monitoring. The approach is designed first and then formally specified. Applications of the resulting model are examined and an operational prototype is implemented. Thus the dissertation establishes a basis for an approach to intelligent monitoring, one which would be equipped to deal effectively with the difficulties that arise in monitoring modern computer systems

    Engineering the performance of parallel applications

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    Parameter dependencies for reusable performance specifications of software components

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    To avoid design-related per­for­mance problems, model-driven performance prediction methods analyse the response times, throughputs, and re­source utilizations of software architectures before and during implementation. This thesis proposes new modeling languages and according model transformations, which allow a reusable description of usage profile dependencies to the performance of software components. Predictions based on this new methods can support performance-related design decisions

    A dynamic prediction and monitoring framework for distributed applications

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    This research builds on an application performance prediction and characterisation environment (known as PACE), whose aim is to characterise the performance-critical elements of both an application and its target execution environment and deduce from this model a predicted behaviour of the application prior to its execution. Underlying the research presented in this thesis are a number of themes: the tasks involved in the performance characterisation of applications and how this might be semi- automated: the level of abstraction at which these characterisations are performed in order to maintain a sufficient predictive accuracy: the automated refinement of these characterisations from runtime performance data: the extension of both the target programming languages and the class of application at which these techniques are aimed. In this thesis a number of novel extensions to PACE are described. These include: a new transaction-based performance characterisation language that provides a flexible framework for describing broader classes of application; a performance monitoring framework (based on an extension to the OpenGroup’s Application Response Measurement (ARM) standard) for the runtime monitoring of an application's data-dependent components and the automated refinement of performance models: an adaptation of this performance characterisation for the prediction of Java applications. These contributions are demonstrated through their application to a number of scientific kernels. This thesis also documents how these predictive results can be used in a real-time distributed runtime management environment, and also how these techniques can be applied to non-scientific codes, in particular to an IBM request-driven distributed web services demonstrator
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