854 research outputs found

    The NASA master directory: Quick reference guide

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    This is a quick reference guide to the NASA Master Directory (MD), which is a free, online, multidisciplinary directory of space and Earth science data sets (NASA and non-NASA data) that are of potential interest to the NASA-sponsored research community. The MD contains high-level descriptions of data sets, other data systems and archives, and campaigns and projects. It provides mechanisms for searching for data sets by important criteria such as geophysical parameters, time, and spatial coverage, and provides information on ordering the data. It also provides automatic connections to a number of data systems such as the NASA Climate Data System, the Planetary Data System, the NASA Ocean Data System, the Pilot Land Data System, and others. The MD includes general information about many data systems, data centers, and coordinated data analysis projects, It represents the first major step in the Catalog Interoperability project, whose objective is to enable researchers to quickly and efficiently identify, obtain information about, and get access to space and Earth science data. The guide describes how to access, use, and exit the MD and lists its features

    Development of a virtual personal video recorder based on a set top box

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    Estágio realizado na Fraunhofer Portugal ResearchTese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Telecomunicações). Faculdade de Engenharia. Universidade do Porto. 200

    QoS SOLUTIONS FORVIDEOCONFERENCING

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    This project is intended to gain knowledge and apply the theory leamt about the need of QoS in videoconferencing and the various options available. Today's conferencing applications are now IP friendly, it can run on either dedicated lines (like ISDN or telephone lines) or IP networks. However, as most network administrators know, conferencingapplications can wreak havoc on unprepared corporate networks. The key to successfully deploying conferencing applications is the activation of Quality of Service (QoS). QoS refers to a network's ability to reliably and consistently provide a certain level of throughput and performance. QoS for conferencing typically involves network availability, bandwidth, end-to-end delay, jitter, and packet loss. Simply stated, if the network doesn't conform to the minimum requirements in any of these areas, the conferences are doomed to fail. QoS can be achieved in a variety of ways, including over-provisioning (deploying additional bandwidth), data prioritization, and the use of QoS-enabled overlay or converged networks. Organizations have two main options for deploying QoS within their organizations; convergence or overlay. Convergence requires the use of QoS-capable WAN links throughout the organization. In many cases, this requires a fork-lift upgrade and migration of all network resources, which can place convergence out of reach of many cost-sensitive organizations. On the other hand, overlay networks allow a step-by-step migration from a non-QoS to a QoS network without the high cost and inherent risk of major network reconfigurations. In this way, overlay networks are a first step toward convergenc

    Proceedings of the Second Annual NASA Science Internet User Working Group Conference

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    Copies of the agenda, list of attendees, meeting summaries, and all presentations and exhibit material are contained. Included are plenary sessions, exhibits of advanced networking applications, and user subgroup meetings on NASA Science Internet policy, networking, security, and user services and applications topics

    A framework for usage management

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    This thesis proposes a formal framework for usage management in distributed systems. The principles of system design are applied in order to standardize certain features of the framework, such as the operational semantics, and leave free of standards areas that necessitate choice and innovation. The framework enables use of multiple policy languages, and dynamic interpretation of usage policies in different computing environments. In addition, the framework provides formal semantics to reason about interoperability of policies with respect to computing environments. The use of this framework in different usage management scenarios is demonstrated including multi-level security, cloud computing and digital rights management (DRM) systems. Furthermore, DRM is cast in a setting that allows the modeling of a number of current approaches within a game theoretic setting. Current strategies that attempt to influence the outcome of such games are analyzed, and a new type of architectural infrastructure that makes novel use of a trust authority is considered in order to create a suitable environment for constructing DRM games that may prove useful in the future

    The Use of Firewalls in an Academic Environment

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    OSI in the NASA science internet: An analysis

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    The Open Systems Interconnection (OSI) protocol suite is a result of a world-wide effort to develop international standards for networking. OSI is formalized through the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). The goal of OSI is to provide interoperability between network products without relying on one particular vendor, and to do so on a multinational basis. The National Institute for Standards and Technology (NIST) has developed a Government OSI Profile (GOSIP) that specified a subset of the OSI protocols as a Federal Information Processing Standard (FIPS 146). GOSIP compatibility has been adopted as the direction for all U.S. government networks. OSI is extremely diverse, and therefore adherence to a profile will facilitate interoperability within OSI networks. All major computer vendors have indicated current or future support of GOSIP-compliant OSI protocols in their products. The NASA Science Internet (NSI) is an operational network, serving user requirements under NASA's Office of Space Science and Applications. NSI consists of the Space Physics Analysis Network (SPAN) that uses the DECnet protocols and the NASA Science Network (NSN) that uses TCP/IP protocols. The NSI Project Office is currently working on an OSI integration analysis and strategy. A long-term goal is to integrate SPAN and NSN into one unified network service, using a full OSI protocol suite, which will support the OSSA user community

    Communication Architecture For Distributed Interactive Simulation (CADIS): Military Standard (draft)

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    Report establishes the requirements for the communication architecture to be used in a distributed interactive simulation, including the standards and the recommended practices for implementing the communication architecture and the rationales behind them

    System for acquisition, processing and presentation of energy consumption

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    Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Telecomunicações). Faculdade de Engenharia. Universidade do Porto. 200

    The SIMBAD astronomical database

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    Simbad is the reference database for identification and bibliography of astronomical objects. It contains identifications, `basic data', bibliography, and selected observational measurements for several million astronomical objects. Simbad is developed and maintained by CDS, Strasbourg. Building the database contents is achieved with the help of several contributing institutes. Scanning the bibliography is the result of the collaboration of CDS with bibliographers in Observatoire de Paris (DASGAL), Institut d'Astrophysique de Paris, and Observatoire de Bordeaux. When selecting catalogues and tables for inclusion, priority is given to optimal multi-wavelength coverage of the database, and to support of research developments linked to large projects. In parallel, the systematic scanning of the bibliography reflects the diversity and general trends of astronomical research. A WWW interface to Simbad is available at: http://simbad.u-strasbg.fr/SimbadComment: 14 pages, 5 Postscript figures; to be published in A&A
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