87,036 research outputs found

    Design and Implementation of a Measurement-Based Policy-Driven Resource Management Framework For Converged Networks

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    This paper presents the design and implementation of a measurement-based QoS and resource management framework, CNQF (Converged Networks QoS Management Framework). CNQF is designed to provide unified, scalable QoS control and resource management through the use of a policy-based network management paradigm. It achieves this via distributed functional entities that are deployed to co-ordinate the resources of the transport network through centralized policy-driven decisions supported by measurement-based control architecture. We present the CNQF architecture, implementation of the prototype and validation of various inbuilt QoS control mechanisms using real traffic flows on a Linux-based experimental test bed.Comment: in Ictact Journal On Communication Technology: Special Issue On Next Generation Wireless Networks And Applications, June 2011, Volume 2, Issue 2, Issn: 2229-6948(Online

    Network emulation focusing on QoS-Oriented satellite communication

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    This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication

    Flexible protection architectures using distributed optical sensors

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    In this paper we describe recent developments in flexible protection schemes that make use of passive fibre Bragg grating (FBG) based transducers for the distributed measurement of voltage and current. The technology underpinning the passive optical approach is described in detail, and both the present development and the future potential of the approach are discussed. In co-operation with Toshiba, the integration of the technique with an existing busbar protection relay is demonstrated, illustrating the flexibility offered by protection schemes that are based on the use of small, passive, multiplexable, dielectric transducers

    MScMS-II: an innovative IR-based indoor coordinate measuring system for large-scale metrology applications

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    According to the current great interest concerning large-scale metrology applications in many different fields of manufacturing industry, technologies and techniques for dimensional measurement have recently shown a substantial improvement. Ease-of-use, logistic and economic issues, as well as metrological performance are assuming a more and more important role among system requirements. This paper describes the architecture and the working principles of a novel infrared (IR) optical-based system, designed to perform low-cost and easy indoor coordinate measurements of large-size objects. The system consists of a distributed network-based layout, whose modularity allows fitting differently sized and shaped working volumes by adequately increasing the number of sensing units. Differently from existing spatially distributed metrological instruments, the remote sensor devices are intended to provide embedded data elaboration capabilities, in order to share the overall computational load. The overall system functionalities, including distributed layout configuration, network self-calibration, 3D point localization, and measurement data elaboration, are discussed. A preliminary metrological characterization of system performance, based on experimental testing, is also presente

    Increasing resilience of ATM networks using traffic monitoring and automated anomaly analysis

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    Systematic network monitoring can be the cornerstone for the dependable operation of safety-critical distributed systems. In this paper, we present our vision for informed anomaly detection through network monitoring and resilience measurements to increase the operators' visibility of ATM communication networks. We raise the question of how to determine the optimal level of automation in this safety-critical context, and we present a novel passive network monitoring system that can reveal network utilisation trends and traffic patterns in diverse timescales. Using network measurements, we derive resilience metrics and visualisations to enhance the operators' knowledge of the network and traffic behaviour, and allow for network planning and provisioning based on informed what-if analysis

    Broadband equivalent circuit derivation for multi-port circuits based on eigen-state formulation

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    In this paper a passive guaranteed wide-band equivalent circuit derivation methodology, attempting to bridge physical geometry considerations with equivalent circuits model extractions, is proposed. Electromagnetic (EM) eigen-states formulation is introduced to bridge between physical topology (geometry) and equivalent network architectures. Instead of casting global Z or Y parameters in pole-residue expansions following or T-networks, the proposed methodology considers eigen-states input impedances/admittances as primary goal functions to derive in canonical equivalent circuit models. While classical or T representations are based on global ground assumptions, the proposed methodology refers to local ground references. The validity of the broadband extraction methodology is demonstrated through correlations with RF measurement carried out on CPW transmission lines and coupled RF inductors up to very high frequencies
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