87,036 research outputs found
Design and Implementation of a Measurement-Based Policy-Driven Resource Management Framework For Converged Networks
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
This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication
Flexible protection architectures using distributed optical sensors
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
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
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
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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