This paper presents the Virtual Imaging Platform (VIP), a platform accessible at http://*** to facilitate the sharing of object models and medical image simulators, and to provide access to distributedcomputing and s...
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This paper presents the Virtual Imaging Platform (VIP), a platform accessible at http://*** to facilitate the sharing of object models and medical image simulators, and to provide access to distributedcomputing and storage resources. A complete overview is presented, describing the ontologies designed to share models in a common repository, the workflow template used to integrate simulators, and the tools and strategies used to exploit computing and storage resources. Simulation results obtained in four image modalities and with different models show that VIP is versatile and robust enough to support large simulations. The platform currently has 200 registered users who consumed 33 years of CPU time in 2011.
Even though the Italian Grid Infrastructure (IGI) is a general purpose distributed platform, in the past it has been used mainly for serial computations. Parallel applications have been typically executed on supercomp...
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ISBN:
(纸本)9780769549392;9781467353212
Even though the Italian Grid Infrastructure (IGI) is a general purpose distributed platform, in the past it has been used mainly for serial computations. Parallel applications have been typically executed on supercomputer facilities or, in case of "not high-end" HPC applications, on local commodity parallel clusters. Nowadays, with the availability of multiple cores processors, Grid computing is becoming very attractive also for parallel applications but some problems exist in supporting of HPC applications on Grid environment. Here we describe the work made to set up a HPC testbed for "not high-end" HPC applications, based on IGI Grid technologies, to find solutions to those problems. Participating sites have been selected among the ones running HPC clusters in Grid environment. Each of them contributed with their specific HPC experience and their available resources to the present test, which encompasses an unprecedented large set of applications from different disciplines in the fields of astronomy, astrophysics, chemistry, climatology, material science and oceanography. In addition to computing resources sharing, the main contribution of each participant was the identification of the real requirements of his application also related to the current middleware limitations and then the realization of a test platform enhanced with additional HPC solutions and configurations developed in a tight collaboration between HPC administrators, users and IGI managers. The main work was on computational resources selection, data management and the definition, the deployment and the documentation of the software execution environment. The outcoming results of the testbed represent the basis of the HPC support in the IGI production infrastructure.
The WS-PGRADE/gUSE generic DCI gateway framework has been developed to support a large variety of user communities. It provides a generic purpose, workflow-oriented graphical user interface to create and run workflows...
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The WS-PGRADE/gUSE generic DCI gateway framework has been developed to support a large variety of user communities. It provides a generic purpose, workflow-oriented graphical user interface to create and run workflows on various DCIs including clusters, Grids, desktop Grids and clouds. The framework can be used by NGIs to support small user communities who cannot afford to develop their own customized science gateway. The WS-PGRADE/gUSE framework also provides two API interfaces (Application Specific Module API and Remote API) to create application-specific science gateways according to the needs of different user communities. The paper describes in detail the workflow concept of WS-PGRADE, the DCI Bridge service that enables access to most of the popular European DCIs and the Application Specific Module and Remote API concepts to generate application-specific science gateways.
OddCI is a new architecture for distributedcomputing that is, at same time, flexible and highly scalable. Previous works have demonstrated the theoretical feasibility of implementing the proposed architecture on a di...
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ISBN:
(纸本)9780769548159
OddCI is a new architecture for distributedcomputing that is, at same time, flexible and highly scalable. Previous works have demonstrated the theoretical feasibility of implementing the proposed architecture on a digital television (DTV) network, but without taking into consideration any practical issues or details. This paper describes the implementation of a proof of concept for the architecture, called OddCI-Ginga, using a testbed based on DTV receivers compatible with the Brazilian DTV System. Performance tests using real broadcast transmission and the return channel demonstrate the feasibility of the model and its usefulness as a platform for efficient and scalable distributedcomputing.
Scheduling tasks in distributed computing infrastructures (DCIs) is challenging mainly because the scheduler is facing a number of more or less dependent parameters that characterize the hosts coming from a particular...
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ISBN:
(纸本)9781467344661;9781467344678
Scheduling tasks in distributed computing infrastructures (DCIs) is challenging mainly because the scheduler is facing a number of more or less dependent parameters that characterize the hosts coming from a particular computing environment and the tasks. In this paper we introduce a multicriteria scheduling method for DCIs, aiming a better matching between hosts, and tasks waiting in a priority queue at a pull-based scheduler. The novelty of the approach consists in employing the Promethee [1] decision aid for selecting tasks. In the aim of computing preference relationships (priorities) among tasks, this approach performs pairwise comparisons of values that characterize tasks. The method exhibits interesting advantages, such as allowing the user to choose the values for the computation of the priorities, like the expected completion time (ECT) and cost. The approach is also very flexible, allowing through a set of parameters the specification of particular scheduling policies. To validate this method we built an XtrebWeb-like simulator, which is capable of running on real traces. We experiment on internet desktop grid (IDG), cloud and best effort grid (BEG), with various workloads. The results show that the Promethee-based scheduling method obtains good performance especially on IDG when certain fractions of the tasks fail. We also prove that multi-criteria scheduling using Promethee performs better than single-criterion scheduling, improving both makespan and cost. Also, a simple definition of ECT is the most efficient in terms of makespan. In this work we also explain the challenges of using Promethee for scheduling in DCIs.
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