82,139 research outputs found

    H2O: An Autonomic, Resource-Aware Distributed Database System

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    This paper presents the design of an autonomic, resource-aware distributed database which enables data to be backed up and shared without complex manual administration. The database, H2O, is designed to make use of unused resources on workstation machines. Creating and maintaining highly-available, replicated database systems can be difficult for untrained users, and costly for IT departments. H2O reduces the need for manual administration by autonomically replicating data and load-balancing across machines in an enterprise. Provisioning hardware to run a database system can be unnecessarily costly as most organizations already possess large quantities of idle resources in workstation machines. H2O is designed to utilize this unused capacity by using resource availability information to place data and plan queries over workstation machines that are already being used for other tasks. This paper discusses the requirements for such a system and presents the design and implementation of H2O.Comment: Presented at SICSA PhD Conference 2010 (http://www.sicsaconf.org/

    Extending Eventually Consistent Cloud Databases for Enforcing Numeric Invariants

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    Geo-replicated databases often operate under the principle of eventual consistency to offer high-availability with low latency on a simple key/value store abstraction. Recently, some have adopted commutative data types to provide seamless reconciliation for special purpose data types, such as counters. Despite this, the inability to enforce numeric invariants across all replicas still remains a key shortcoming of relying on the limited guarantees of eventual consistency storage. We present a new replicated data type, called bounded counter, which adds support for numeric invariants to eventually consistent geo-replicated databases. We describe how this can be implemented on top of existing cloud stores without modifying them, using Riak as an example. Our approach adapts ideas from escrow transactions to devise a solution that is decentralized, fault-tolerant and fast. Our evaluation shows much lower latency and better scalability than the traditional approach of using strong consistency to enforce numeric invariants, thus alleviating the tension between consistency and availability

    Security oriented e-infrastructures supporting neurological research and clinical trials

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    The neurological and wider clinical domains stand to gain greatly from the vision of the grid in providing seamless yet secure access to distributed, heterogeneous computational resources and data sets. Whilst a wealth of clinical data exists within local, regional and national healthcare boundaries, access to and usage of these data sets demands that fine grained security is supported and subsequently enforced. This paper explores the security challenges of the e-health domain, focusing in particular on authorization. The context of these explorations is the MRC funded VOTES (Virtual Organisations for Trials and Epidemiological Studies) and the JISC funded GLASS (Glasgow early adoption of Shibboleth project) which are developing Grid infrastructures for clinical trials with case studies in the brain trauma domain

    Towards data grids for microarray expression profiles

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    The UK DTI funded Biomedical Research Informatics Delivered by Grid Enabled Services (BRIDGES) project developed a Grid infrastructure through which research into the genetic causes of hypertension could be supported by scientists within the large Wellcome Trust funded Cardiovascular Functional Genomics project. The BRIDGES project had a focus on developing a compute Grid and a data Grid infrastructure with security at its heart. Building on the work within BRIDGES, the BBSRC funded Grid enabled Microarray Expression Profile Search (GEMEPS) project plans to provide an enhanced data Grid infrastructure to support richer queries needed for the discovery and analysis of microarray data sets, also based upon a fine-grained security infrastructure. This paper outlines the experiences gained within BRIDGES and outlines the status of the GEMEPS project, the open challenges that remain and plans for the future

    The NASA Astrophysics Data System: Architecture

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    The powerful discovery capabilities available in the ADS bibliographic services are possible thanks to the design of a flexible search and retrieval system based on a relational database model. Bibliographic records are stored as a corpus of structured documents containing fielded data and metadata, while discipline-specific knowledge is segregated in a set of files independent of the bibliographic data itself. The creation and management of links to both internal and external resources associated with each bibliography in the database is made possible by representing them as a set of document properties and their attributes. To improve global access to the ADS data holdings, a number of mirror sites have been created by cloning the database contents and software on a variety of hardware and software platforms. The procedures used to create and manage the database and its mirrors have been written as a set of scripts that can be run in either an interactive or unsupervised fashion. The ADS can be accessed at http://adswww.harvard.eduComment: 25 pages, 8 figures, 3 table

    Why Print and Electronic Resources Are Essential to the Academic Law Library

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    Libraries have supported multiple formats for decades, from paper and microforms to audiovisual tapes and CDs. However, the newest medium, digital transmission, has presented a wider scope of challenges and caused library patrons to question the established and recognized multiformat library. Within the many questions posed, two distinct ones echo repeatedly. The first doubts the need to sustain print in an increasingly digital world, and the second warns of the dangers of relying on a still-developing technology. This article examines both of these positions and concludes that abandoning either format would translate into a failure of service to patrons, both present and future

    Designing privacy for scalable electronic healthcare linkage

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    A unified electronic health record (EHR) has potentially immeasurable benefits to society, and the current healthcare industry drive to create a single EHR reflects this. However, adoption is slow due to two major factors: the disparate nature of data and storage facilities of current healthcare systems and the security ramifications of accessing and using that data and concerns about potential misuse of that data. To attempt to address these issues this paper presents the VANGUARD (Virtual ANonymisation Grid for Unified Access of Remote Data) system which supports adaptive security-oriented linkage of disparate clinical data-sets to support a variety of virtual EHRs avoiding the need for a single schematic standard and natural concerns of data owners and other stakeholders on data access and usage. VANGUARD has been designed explicit with security in mind and supports clear delineation of roles for data linkage and usage

    User-Based Data Collection Techniques and Strategies for Evaluating Networked Information Services

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