2,677 research outputs found

    Non-recursive equivalent of the conjugate gradient method without the need to restart

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    A simple alternative to the conjugate gradient(CG) method is presented; this method is developed as a special case of the more general iterated Ritz method (IRM) for solving a system of linear equations. This novel algorithm is not based on conjugacy, i.e. it is not necessary to maintain overall orthogonalities between various vectors from distant steps. This method is more stable than CG, and restarting techniques are not required. As in CG, only one matrix-vector multiplication is required per step with appropriate transformations. The algorithm is easily explained by energy considerations without appealing to the A-orthogonality in n-dimensional space. Finally, relaxation factor and preconditioning-like techniques can be adopted easily.Comment: 9 page

    Banking Performance in South-Eastern Europe During the Interwar Period

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    In the framework of the broader political and economic development of the individual states on Balkan Peninsula the author has made the comparison between the performance of the banking sector in Yugoslavia, Romania, Greece and Bulgaria. The analysis was carried out on the sample of balance sheets for the most important joint stock banking companies in the respective countries in the years 1928 and 1929 which represent the peak of the activity and performance of banks in region. In the following years the whole region sank in the abyss of the Great Depression of the thirties when the issue of banking performance was considered on the different way. One of the common features of the banks in region is certainly the prevailing role of short-term resources and a huge imbalance in interest incomes and incomes from other bank transactions. This fact does not only testify to high margins and effective interest rates, but also to a limited portfolio in bank services and other transactions, which was the consequence of the social and economic environment that banks had to operate in.South-eastern Europe; Banks; Banking; Balance sheets.

    Resource and Application Models for Advanced Grid Schedulers

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    As Grid computing is becoming an inevitable future, managing, scheduling and monitoring dynamic, heterogeneous resources will present new challenges. Solutions will have to be agile and adaptive, support self-organization and autonomous management, while maintaining optimal resource utilisation. Presented in this paper are basic principles and architectural concepts for efficient resource allocation in heterogeneous Grid environment

    A Study of Grid Applications: Scheduling Perspective

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    As the Grid evolves from a high performance cluster middleware to a multipurpose utility computing framework, a good understanding of Grid applications, their statistics and utilisation patterns is required. This study looks at job execution times and resource utilisations in a Grid environment, and their significance in cluster and network dimensioning, local level scheduling and resource management

    Enabling Adaptive Grid Scheduling and Resource Management

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    Wider adoption of the Grid concept has led to an increasing amount of federated computational, storage and visualisation resources being available to scientists and researchers. Distributed and heterogeneous nature of these resources renders most of the legacy cluster monitoring and management approaches inappropriate, and poses new challenges in workflow scheduling on such systems. Effective resource utilisation monitoring and highly granular yet adaptive measurements are prerequisites for a more efficient Grid scheduler. We present a suite of measurement applications able to monitor per-process resource utilisation, and a customisable tool for emulating observed utilisation models. We also outline our future work on a predictive and probabilistic Grid scheduler. The research is undertaken as part of UK e-Science EPSRC sponsored project SO-GRM (Self-Organising Grid Resource Management) in cooperation with BT

    Managing Uncertainty: A Case for Probabilistic Grid Scheduling

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    The Grid technology is evolving into a global, service-orientated architecture, a universal platform for delivering future high demand computational services. Strong adoption of the Grid and the utility computing concept is leading to an increasing number of Grid installations running a wide range of applications of different size and complexity. In this paper we address the problem of elivering deadline/economy based scheduling in a heterogeneous application environment using statistical properties of job historical executions and its associated meta-data. This approach is motivated by a study of six-month computational load generated by Grid applications in a multi-purpose Grid cluster serving a community of twenty e-Science projects. The observed job statistics, resource utilisation and user behaviour is discussed in the context of management approaches and models most suitable for supporting a probabilistic and autonomous scheduling architecture
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