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Simone Speziale - One of the best experts on this subject based on the ideXlab platform.
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Twisted Geometries Coherent States for Loop Quantum Gravity
Classical and Quantum Gravity, 2020Co-Authors: Etera R. Livine, Andrea Calcinari, Laurent Freidel, Simone SpezialeAbstract:We introduce a new family of coherent states for loop quantum gravity, inspired by the twisted geometry parametrization. We compute their Peakedness properties and compare them with the heat-kernel coherent states. They show similar features for the area and the holonomy operators, but improved Peakedness in the direction of the flux. At the gauge-invariant level, the new family is built from tensor products of coherent intertwiners. To study the Peakedness of the holonomy operator, we introduce a new shift operator based on the harmonic oscillator representation associated with the twisted geometry parametrization. The new shift operator captures the components of the holonomy relevant to disentangle its action into a simple positive shift of the spins.
Tanos Elfouhaily - One of the best experts on this subject based on the ideXlab platform.
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importance of Peakedness in sea surface slope measurements and applications
Journal of Geophysical Research, 2000Co-Authors: Bertrand Chapron, Vincent Kerbaol, D Vandemark, Tanos ElfouhailyAbstract:We recall the simple statistical concept that non-Gaussian distribution Peakedness results from the compounding of random processes. This idea is applied to observations and analysis of sea surface slopes as inferred using optical and microwave-scattering measurements. Our study emphasizes the importance of identifying and quantifying the distribution variance and kurtosis from observations. Data are shown to indicate consistently non-Gaussian Peakedness, to indicate the need to report at least two parameters in an even order analysis, and to indicate near equivalence between radar and optical data. Physical interpretation for observed infrequent steep slopes is given via compounding statistical processes where normally distributed short-scale waves are modulated because of random fluctuations mainly associated with the underlying long wave field. Implications of non-Gaussian Peakedness are provided for altimeter backscatter theory and for modeling wave-breaking probability.
Gopalakrishnan Ramamurthy - One of the best experts on this subject based on the ideXlab platform.
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Peakedness measures for traffic characterization in high speed networks
International Conference on Computer Communications, 1997Co-Authors: Brian L Mark, D L Jagerman, Gopalakrishnan RamamurthyAbstract:In high-speed networks based on asynchronous transfer mode (ATM), variable bit rate (VBR) sources generate bursty cell streams which share the link bandwidth wherever multiplexing occurs. In theory, the bandwidth requirement per stream to support a given quality-of-service at a multiplexer should generally decrease as the number of streams increases. In practice, high statistical multiplexing gain is difficult to achieve because good traffic characterizations are usually not available. This paper proposes the use of Peakedness-based measures to capture the statistical information from traffic streams needed to determine bandwidth allocations. The standard definition of Peakedness applies only to point process models of traffic. Yet fluid models of traffic have certain advantages in terms of tractability. Hence, we introduce a new measure called modified Peakedness, which encompasses point process and fluid models under a common framework. We develop some of its properties and specialize it to several common traffic models. Finally, we study the effectiveness of the Peakedness/modified Peakedness as burstiness measures for real-time traffic.
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Peakedness of stochastic models for high speed network traffic
International Symposium on Information Theory, 1995Co-Authors: Brian L Mark, D L Jagerman, Gopalakrishnan RamamurthyAbstract:In networks based on the asynchronous transfer mode (ATM), information is transmitted asynchronously over high-speed links in the form of 53-byte units called cells. Accurate traffic characterization is a crucial step in performing network resource allocation and dimensioning. Peakedness was originally developed by teletraffic engineers as a tool for characterizing call arrival processes at a trunk group. We generalize the Peakedness theory to include a class of stochastic models used in studies of high-speed networks and apply it to the approximate analysis of a statistical multiplexer.
Ferreira M. A. M. - One of the best experts on this subject based on the ideXlab platform.
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Study of a collection of service time distributions and impact in the respective M|G|8 system busy period parameters
Slovak University of Technology, 2018Co-Authors: Ferreira M. A. M., Filipe J. A.Abstract:The problems arising when computing the moments of a particular service time distributions collection, for which the M|G|? queue system busy period becomes very easy to study, are presented and it is shown how to overcome them. Some results, precisely about the moment’s computation of random variables with distribution functions given by this collection are given. The busy period “Peakedness” and “modified Peakedness” for the M|G|? queue in the case of those service time distributions are also computed
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A particular collection of service time distributions parameters study and impact in some M|G|? system busy period and busy cycle parameters
Universum Research E-Center, 2017Co-Authors: Ferreira M. A. M.Abstract:The problems arising when the moments of service time distributions, for which the M|G|? queue system busy period and busy cycle become very easy to study, are presented and it is shown how to overcome them. The busy cycle renewal function and the “Peakedness” and the “modified Peakedness” for the M|G|? busy period and busy cycle in the case of those service time distributions are also computed.info:eu-repo/semantics/publishedVersio
Etera R. Livine - One of the best experts on this subject based on the ideXlab platform.
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Twisted Geometries Coherent States for Loop Quantum Gravity
Classical and Quantum Gravity, 2020Co-Authors: Etera R. Livine, Andrea Calcinari, Laurent Freidel, Simone SpezialeAbstract:We introduce a new family of coherent states for loop quantum gravity, inspired by the twisted geometry parametrization. We compute their Peakedness properties and compare them with the heat-kernel coherent states. They show similar features for the area and the holonomy operators, but improved Peakedness in the direction of the flux. At the gauge-invariant level, the new family is built from tensor products of coherent intertwiners. To study the Peakedness of the holonomy operator, we introduce a new shift operator based on the harmonic oscillator representation associated with the twisted geometry parametrization. The new shift operator captures the components of the holonomy relevant to disentangle its action into a simple positive shift of the spins.
