2,255 research outputs found

    Which quantum states are dual to classical spacetimes?

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    It is commonly accepted that states in a conformal field theory correspond to classical spacetimes with Anti-de-Sitter asymptotics. In this work we give a prescription for the CFT states with a dual classical spacetime and, using basic holographic rules, show that they are holographically connected to coherent states in the large-N limit, or by considering linearized perturbations. We also point out implications in the spacetime emergence mechanism, for instance, the (entangled) state dual to the black hole should be properly described as a quantum superposition of products of these states. This also complements the quantum interpretation of the Hawking-Page transition.Comment: 14 pages, 8 figure

    BGP-like TE Capabilities for SHIM6

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    In this paper we present a comprehensive set of mechanisms that restore to the site administrator the capacity of enforcing traffic engineering (TE) policies in a multiaddressed IPv6 scenario. The mechanisms rely on the ability of SHIM6 to securely perform locator changes in a transparent fashion to transport and application layers. Once an outgoing path has been selected for a communication by proper routing configuration in the site, the source prefix of SHIM6 data packets is rewritten by the site routers to avoid packet discarding due to ingress filtering. The SHIM6 locator preferences exchanged in the context establishment phase are modified by the site routers to influence in the path used for receiving traffic. Scalable deployment is ensured by the stateless nature of these mechanisms.Publicad

    Fault Tolerant Scalable Support for Network Portability and Traffic Engineering

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    The P-SHIM6 architecture provides ISP independence to IPv6 sites without compromising scalability. This architecture is based on a middle-box, the P-SHIM6, which manages the SHIM6 protocol exchange on behalf of the nodes of a site, which are configured with provider independent addresses. Incoming and outgoing packets are processed by the P-SHIM6 box, which can assign different locators to a given communication, either when it is started, or dynamically after the communication has been established. As a consequence, changes required for provider portability are minimized, and fine-grained Traffic Engineering can be enforced at the P-SHIM6 box, in addition to the fault tolerance support provided by SHIM6.This project has been supported by the RiNG project IST-2005-035167 and by the IMPROVISA project TSI2005-07384-C03-02.Publicad

    Ventajas y desventajas del sistema de rotación de enfermeros

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    El presente trabajo se ha realizado teniendo en cuenta las situaciones que se plantean con el sistema de rotación en los servicios de enfermería en relación al nivel de satisfacción del personal, sus ventajas y desventajas. Se utilizó como universo el total de enfermeros del Hospital J.N. Lencinas. Se realizo un estudio de tipo cuali-cuantitativo, descriptivo transversal. Los datos fueron obtenidos a través de encuesta personal y anónima. Y se proceso a través de planilla Excel. Dentro del Marco teórico se utilizaron las distintas teorías del placer y el displacer, las distintas teorías motivacionales, y los tipos de rotación que se utilizan en los servicios de salud, buscando explicar las motivaciones del ser humano, y su relación con el entorno laboral, Intentando establecer, como el sistema de rotación hospitalaria, repercuten en la vida social, familiar y laboral del personal de enfermería. Buscando que el presente trabajo sirva de referencia para posteriores estudios que involucren la rotación de servicio dentro de la problemática laboral del personal de enfermería. RESULTADOS: Las ventajas más significativas en general fueron A (el mayor conocimiento y habilidades) y E (26%) crecimiento profesional (22%), pero a la hora de comparar dicho beneficios, con las desventajas, aun cuando su rotación fue consensuada, no dejaron de sentir la sensación de amenaza a su vida social y familiar, ya que el 17% eligió la opción E (rompimiento en la vida social y familiar) , el 12 % la opción I (actitud negativa al cambio) y el 11% la opción A (adaptación disfuncional al nuevo equipo). Como una conclusión final y relacionando que debido al tipo de trabajo que realiza el personal de enfermería durante todos los días del año y las 24 hs, el cual requiere una mayor necesidad de seguridad en cuanto a su ámbito laboral y familiar, por lo cual la rotación es percibida como una amenaza al mismo.Fil: Dellafazia, Julia. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería..Fil: Maldonado. Marcelo. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería..Fil: Martínez, Marcelo. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería.

    An Architecture for Network Layer Privacy

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    We present an architecture for the provision of network layer privacy based on the SHIM6 multihoming protocol. In its basic form, the architecture prevents on-path eavesdroppers from using SHIM6 network layer information to correlate packets that belong to the same communication but use different locators. To achieve this, several extensions to the SHIM6 protocol and to the HBA (Hash Based Addresses) addressing model are defined. On its full-featured mode of operation, hosts can vary dynamically the addresses of the packets of on-going communications. Single-homed hosts can adopt the SHIM6 protocol with the privacy enhancements to benefit from this protection against information collectors.IEEE Communications SocietyPublicad

    Efficient security for IPv6 multihoming

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    In this note, we propose a security mechanism for protecting IPv6 networks from possible abuses caused by the malicious usage of a multihoming protocol. In the presented approach, each multihomed node is assigned multiple prefixes from its upstream providers, and it creates the interface identifier part of its addresses by incorporating a cryptographic one-way hash of the available prefix set. The result is that the addresses of each multihomed node form an unalterable set of intrinsically bound IPv6 addresses. This allows any node that is communicating with the multihomed node to securely verify that all the alternative addresses proposed through the multihoming protocol are associated to the address used for establishing the communication. The verification process is extremely efficient because it only involves hash operationsPublicad

    An API for IPv6 Multihoming based on HBA and CGA

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    EUNICE 2005. IFIP International Workshop on Networked Applications, Colmenarejo, Madrid/Spain, 6–8 July, 2005. (Proceedings of the 11th Open European Summer School EUNICE 2005: Networked Applications)This paper proposes an API for Multihoming in IPv6. This API is based on the Hash Based Addresses and Cryptographically Generated Addresses approaches, which are being developed by the IETF multi6 Working Group. The support of Multihoming implies several actions such as failure detection procedures, reachability tests, re-homing procedures and exchange of locators. Applications can benefit from transparent access to Multihoming services only if per host Multihoming parameters are defined. However, more benefits could be obtained by applications if they will be able to configure these parameters. The proposed Multihoming API provides different functions to applications which can modify some parameters and invoke some functions related with the Multihoming Layer.This work has been partly supported by the European Union under the E-Next Project FP6506869 and by OPTINET6 project TIC-2003-09042-C03-01

    Traffic engineering in multihomed sites

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    It is expected that IPv6 multihomed sites will obtain as many global prefixes as direct providers they have, so traffic engineering techniques currently used in IPv4 multihomed sites is no longer suitable. However, traffic engineering is required for several reasons, and in particular, for being able to properly support multimedia communications. In this paper we present a framework for traffic engineering in IPv6 multihomed sites with multiple global prefixes. Within this framework, we have included several tools such as DNS record manipulation and proper configuration of the policy table defined in RFC 3484. To provide automation in the management of traffic engineering, we analyzed the usage of two mechanisms to configure the policy table.This work has been partly supported by the European Union under the E-Next Project FP6-506869 and by the OPTINET6 project TIC-2003-09042-C03-01.Publicad

    An API for IPv6 Multihoming

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    IFIP International Workshop on Networked Applications, Colmenarejo, Madrid/Spain, 6?8 July, 2005This paper proposes an API for Multihoming in IPv6. This API is based on the Hash Based Addresses and Cryptographically Generated Addresses approaches, which are being developed by the IETF multi6 Working Group. The support of Multihoming implies several actions such as failure detection procedures, reachability tests, re-homing procedures and exchange of locators. Applications can benefit from transparent access to Multihoming services only if per host Multihoming parameters are defined. However, more benefits could be obtained by applications if they will be able to configure these parameters. The proposed Multihoming API provides different functions to applications which can modify some parameters and invoke some functions related with the Multihoming Layer.Publicad

    IPv6 Multihoming Support in the Mobile Internet

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    Fourth-generation mobile devices incorporate multiple interfaces with diverse access technologies. The current Mobile IPv6 protocol fails to support the enhanced fault tolerance capabilities that are enabled by the availability of multiple interfaces. In particular, established MIPv6 communications cannot be preserved through outages affecting the home address. In this article, we describe an architecture for IPv6 mobile host multihoming that enables transport layer survivability through multiple failure modes. The proposed approach relies on the cooperation between the MIPv6 and the SHIM6 protocols.Publicad
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