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    Publicado el 19.7.2013 por Pablo Hermoso de Mendoza González

    Bigtable is a distributed storage system for managing structured data that is designed to scale to a very
    large size: petabytes of data across thousands of commodity servers. Many projects at Google store data
    in Bigtable, including web indexing, Google Earth, and Google Fi-nance.
     
    These applications place very different demands on Bigtable, both in terms of data size (from URLs to web
    pages to satellite imagery) and latency requirements.

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    Publicado el 20.6.2013 por Pablo Hermoso de Mendoza González

    Shubham Gupta, Pedro Szekely, Craig A. Knoblock, Aman Goel, Mohsen Taheriyan, and Maria Muslea
    University of Southern California
    Information Sciences Institute and Department of Computer Science
     
    The Linked Data cloud contains large amounts of RDF data generated from databases. Much of this RDF data, generated using tools such as D2R, is expressed in terms of vocabularies automatically derived from the schema of the original database. The generated RDF would be signicantly more useful if it were expressed in terms of commonly used vocabularies. Using today's tools, it is labor-intensive to do this. For example, one can first use D2R to automatically generate RDF from a database and then use R2R to translate the automatically generated RDF into RDF expressed in a new vocabulary. The problem is that dening the R2R mappings is dicult and labor intensive because one needs to write the mapping rules in terms of SPARQL graph patterns.
     
    In this work, we present a semi-automatic approach for building mappings that translate data in structured sources to RDF expressed in terms of a vocabulary of the user's choice. Our system, Karma, automatically derives these mappings, and provides an easy to use interface that enables users to control the automated process to guide the system to produce the desired mappings. In our evaluation, users need to interact with the system less than once per column (on average) in order to construct the desired mapping rules. The system then uses these mapping rules to generate semantically rich RDF for the data sources.
    We demonstrate Karma using a bioinformatics example and contrast it with other approaches used in that community. Bio2RDF [7] and Semantic MediaWiki Linked Data Extension (SMW-LDE) [2] are examples of efforts that integrate bioinformatics datasets by mapping them to a common vocabulary. We applied our approach to a scenario used in the SMW-LDE that integrate ABA, Uniprot, KEGG Pathway, PharmGKB and Linking Open Drug Data datasets using a common vocabulary. In this demonstration, we rst show how a user can inter-actively map these datasets to the SMW-LDE vocabulary, and then we use thesemappings to generate RDF for these sources.

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    Compartido el 9.3.2011 por Equipo GNOSS

    Ontology-Based RFID System Model for Supporting Semantic Consistency in Ubiquitous Environment

    The emerging ubiquitous computing is changing the current computing paradigm, and lets the ubiquitous RFID applications consistently and independently utilize the sensed information from the intelligent and powerful tags which are in a variety of applications fields. One of the most important issues is how to support the semantic consistency between data from various tags in different RFID applications under ubiquitous environment. This paper proposes a new RFID model to resolve the issue and to support the application-independent semantic maintenance in the ubiquitous computing environment based on WordNet, a widely used ontology. Our noble RFID model provides an infrastructure support for the semantic consistency and enables the RFID application-independent informat

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    Compartido el 13.1.2010 por Ricardo Alonso Maturana

    Freebase es una base de datos social abierta con más de 10.000.000 de conceptos interconectados. El producto pertenece a Metaweb Technologies, empresa creada en 2005 con base en San Francisco. Este es su primer producto. Entre sus usuarios cabe destacar a Bing o Zemanta. Muy interesante para los que trabajan en la creación de contextos web semánticamente enriquecidos.

    "Freebase, created by Metaweb Technologies, is an open database of the world’s information. It’s built by the community and for the community – free for anyone to query, contribute to, build applications on top of, or integrate into their websites.

    Already, Freebase covers millions of topics in hundreds of categories. Drawing from large open data sets like Wikipedia, MusicBrainz, and the SEC archives, it contains structured information on many popular topics, including movies, music, people and locations – all reconciled and freely available via an open API. This information is supplemented by the efforts of a passionate global community of users who are working together to add structured information on everything from philosophy to European railway stations to the chemical properties of common food ingredients"

    By structuring the world’s data in this manner, the Freebase community is creating a global resource that will one day allow people and machines everywhere to access information far more easily and quickly than they can today"

     

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