10 research outputs found

    A federated information management system for the Deep Space Network

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    General requirements for an information management system for the deep space network (DSN) are examined. A concise review of available database management system technology is presented. It is recommended that a federation of logically decentralized databases be implemented for the Network Information Management System of the DSN. Overall characteristics of the federation are specified, as well as reasons for adopting this approach

    Exploiting Information-centric Networking to Federate Spatial Databases

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    This paper explores the methodologies, challenges, and expected advantages related to the use of the information-centric network (ICN) technology for federating spatial databases. ICN services allow simplifying the design of federation procedures, improving their performance, and providing so-called data-centric security. In this work, we present an architecture that is able to federate spatial databases and evaluate its performance using a real data set coming from OpenStreetMap within a heterogeneous federation formed by MongoDB and CouchBase spatial database systems

    Towards Accessible, Usable Knowledge Frameworks in Engineering

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    A substantial amount of research has been done in the field of engineering knowledge management, where countless ontologies have been developed for various applications within the engineering community. However, despite the success shown in these research efforts, the techniques have not been adopted by industry. This research aims to uncover the reasons for the slow adoption of engineering knowledge frameworks, namely ontologies, in industry. There are two projects covered in this thesis. The first project is the development of a cross-domain ontology for the Biomesh Project, which spans the fields of mechanical engineering, biology, and anthropology. The biology community is known for its embrace of ontologies and has made their use quite popular with the creation of the Gene Ontology. This ontology spawned the establishment of the Open Biological and Biomedical Ontologies (OBO) Foundry, a consortium which approves and curates ontologies in the biology field. No such consortium exists in the field of engineering. This project demonstrates the usefulness of curated reference ontologies. Ontological knowledge bases in four different domains were imported and integrated together to connect previously disparate information. A case study with data from the Biomesh Project demonstrates cross-domain queries and inferences that were not possible before the creation of this ontology. In the second part of this thesis we investigate the usability of current ontology tools. Protégé, the most popular ontology editing tool, is compared to OntoWiki, a semantic wiki. This comparison is done using proven techniques from the field of Human-computer interaction to uncover usability problems and point out areas where each system excels. A field of 16 subjects completed a set of tasks in each system and gave feedback based on their experience. It is shown that while OntoWiki offers users a satisfying interface, it lacks in some areas that can be easily improved. Protégé provides users with adequate functionality, but it is not intended for a novice user

    Configuração e interrogação com sistemas federados

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    Apesar da existência de produtos comerciais e da investigação na área, a construção de sistemas de informação com diversos componentes distribuídos, heterogéneos e autónomos - conhecidos como sistemas de informação federados - é ainda um desafio. Estes sistemas de informação oferecem uma visão global unificada sobre os vários modelos de dados (parciais). No entanto, a modelação destes sistemas é um desafio, já que modelos de dados como o relacional não incluem informação sobre a distribuição e tratamento de heterogeneidade. É também necessário interagir com estes sistemas de informação, através de interrogações sobre os diversos componentes dos sistemas, sem ser necessário conhecer os detalhes dos mesmos. Este trabalho propõe uma abordagem a estes desafios, através da utilização de modelos para descrição semântica, e.g. linguagem OWL (Ontology Web Language), para construir uma descrição unificada dos seus diversos modelos parciais. O modelo criado para dar suporte a esta descrição é, em parte, baseado em ontologias existentes, que foram alteradas e extendidas para resolver diversos desafios de modelação. Sobre este modelo, é criado um componente de software que permite a execução de interrogações SQL (Structured Query Language) sobre o sistema federado, resolvendo os problemas de distribuição e heterogeneidade existentes

    Interactive on-line conferences

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    Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1984.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.Vita.Bibliography: leaves 223-234.by Sunil Kumar Sarin.Ph.D

    Evaluation of Functional Data Models for Database Design and Use

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    The problems of design, operation, and maintenance of databases using the three most popular database management systems (Hierarchical, CQDASYL/DBTG, and Relational) are well known. Users wishing to use these systems have to make conscious and often complex mappings between the real-world structures and the data structuring options (data models) provided by these systems. In addition, much of the semantics associated with the data either does not get expressed at all or gets embedded procedurally in application programs in an ad-hoc way. In recent years, a large number of data models (called semantic data models) have been proposed with the aim of simplifying database design and use. However, the lack of usable implementations of these proposals has so far inhibited the widespread use of these concepts. The present work reports on an effort to evaluate and extend one such semantic model by means of an implementation. It is based on the functional data model proposed earlier by Shipman[SHIP81). We call this 'Extended Functional Data Model' (EFDM). EFDM, like Shipman's proposals, is a marriage of three of the advanced modelling concepts found in both database and artificial intelligence research: the concept of entity to represent an object in the real world, the concept of type hierarchy among entity types, and the concept of derived data for modelling procedural knowledge. The functional notation of the model lends itself to high level data manipulation languages. The data selection in these languages is expressed simply as function application. Further, the functional approach makes it possible to incorporate general purpose computation facilities in the data languages without having to embed them in procedural languages. In addition to providing the usual database facilities, the implementation also provides a mechanism to specify multiple user views of the database

    A federated architecture for database systems

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