Jesús Carretero

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Simulation techniques have become a powerful tool for deciding the best starting conditions on pay-as-you-go scenarios. This is the case of public cloud infrastructures, where a given number and type of virtual machines (in short VMs) are instantiated during a specified time, being this reflected in the final budget. With this in mind, this paper introduces(More)
Data replication is a practical and effective method to achieve efficient and fault-tolerant data access in grids. Traditionally, data replication schemes maintain an entire replica in each site where a file is replicated, providing a read-onlymodel. These solutions require huge storage resources to store thewhole set of replicas and do not allow efficient(More)
In this work, we propose new techniques to analyze the behavior, the performance, and specially the scalability of High Performance Computing (in short, HPC) applications on different computing architectures. Our final objective is to test applications using a wide range of architectures (real or merely designed) and scaling it to any number of nodes or(More)
This special issue of the cluster computing journal will feature articles that discuss tools and applications for cloud computing. Specifically, it aims at delivering the state-of-the-art research on current cloud computing tools topics, and at promoting the cloud applications discipline by bringing to the attention of the community novel problems that must(More)
Workload variations on Internet platforms such as YouTube, Flickr, LastFM require novel approaches to dynamic resource provisioning in order to meet QoS requirements, while reducing the Total Cost of Ownership (TCO) of the infrastructures. The economy of scale promise of cloud computing is a great opportunity to approach this problem, by developing elastic(More)
power growth has not been corresponded with an equivalent improvement in I /O bandwidth. As a result, computation, memory and I /O are more unbalanced every year, with more MPP applications being I /O bounded. This paper gives an overview of ParFiSys, a parallel file system developed at the UPM to provide I /O services to the GPMIMD machine, an MPP(More)
We studied the effect on journal impact factors (JIF) of citations from documents labeled as articles and reviews (usually peer reviewed) versus citations coming from other documents. In addition, we studied the effect on JIF of the number of citing records. This number is usually different from the number of citations. We selected a set of 700 journals(More)
Data management is one of the most important problems in grid environments. Most of the efforts in data management in grids have been focused on data replication. Data replication is a practical and effective method to achieve efficient data access in grids. However all data replication schemes lack in providing a grid file system. One important challenge(More)