10,615 research outputs found

    RMD (Resource Management in Diffserv) QoS-NSLP model

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    This draft describes a local QoS model, denoted as Resource Management in Diffserv (RMD) QoS model, for NSIS that extends the IETF Differentiated Services (Diffserv) architecture with a scalable admission control and resource reservation concept. The specification of this QoS model includes a description of its QoS parameter information, as well as how that information should be treated or interpreted in the network

    Gradual Program Analysis

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    Dataflow analysis and gradual typing are both well-studied methods to gain information about computer programs in a finite amount of time. The gradual program analysis project seeks to combine those two techniques in order to gain the benefits of both. This thesis explores the background information necessary to understand gradual program analysis, and then briefly discusses the research itself, with reference to publication of work done so far. The background topics include essential aspects of programming language theory, such as syntax, semantics, and static typing; dataflow analysis concepts, such as abstract interpretation, semilattices, and fixpoint computations; and gradual typing theory, such as the concept of an unknown type, liftings of predicates, and liftings of functions

    RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv

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    This document describes a Next Steps in Signaling (NSIS) Quality-of- Service (QoS) Model for networks that use the Resource Management in Diffserv (RMD) concept. RMD is a technique for adding admission control and preemption function to Differentiated Services (Diffserv) networks. The RMD QoS Model allows devices external to the RMD network to signal reservation requests to Edge nodes in the RMD network. The RMD Ingress Edge nodes classify the incoming flows into traffic classes and signals resource requests for the corresponding traffic class along the data path to the Egress Edge nodes for each flow. Egress nodes reconstitute the original requests and continue forwarding them along the data path towards the final destination. In addition, RMD defines notification functions to indicate overload situations within the domain to the Edge nodes

    LC-PCN: The Load Control PCN Solution

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    There is an increased interest of simple and scalable resource provisioning solution for Diffserv network. The Load Control PCN (LC-PCN) addresses the following issues:\ud o Admission Control for real time data flows in stateless Diffserv Domains\ud o Flow Termination: Termination of flows in case of exceptional events, such as severe congestion after re-routing.\ud Admission control in a Diffserv stateless domain is a combination of:\ud o Probing, whereby a probe packet is sent along the forwarding path in a network to determine whether a flow can be admitted based upon the current congestion state of the network\ud o Admission Control based on data marking, whereby in congestion situations the data packets are marked to notify the PCN-egress-node that a congestion occurred on a particular PCN-ingress-node to PCN-egress-node path.\ud \ud The scheme provides the capability of controlling the traffic load in the network without requiring signaling or any per-flow processing in the PCN-interior-nodes. The complexity of Load Control is kept to a minimum to make implementation simple.\u

    Utilisation des incertitudes associées aux mesures altimétriques satellitaires de plan d'eau

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    On cherche comment utiliser les incertitudes I associées aux mesures altimétriques satellitaires de plan d'eau Y, pour quantifier l'imprécision des régressions établies entre de telles mesures et des cotes X mesurées au sol. Le but consiste à connaître les erreurs types résiduelles de régression qu'on obtiendrait si chaque valeur Yi de la série de base était remplacée par une distribution normale de moyenne Yi et d'écart type Ii. Par une méthode numérique basée sur l'utilisation de nombreux jeux de données différents, on montre les résultats suivants de portée générale, dont certains sont justifiés de façon théorique : Pour la régression exprimant Y en fonction de X : Les droites de régression sont identiques sur la série de base et la série étendue ; L'erreur type résiduelle de régression E1re sur la série étendue est fonction de l'erreur type résiduelle de régression E1rb sur la série de base et de la moyenne quadratique MQIb des incertitudes I sur la série de base : E1re = (E1rb2 + MQIb2)0.5 (0). Pour la régression exprimant X en fonction de Y : Les droites de régression calculées sur la série de base et la série étendue diffèrent. Leurs coefficients directeurs respectifs A2b et A2e sont tels que le rapport A2e/A2b, toujours inférieur ou égal à 1, décroît en fonction du rapport MQIb/ETYb, où ETYb désigne l'écart type de Y sur la série de base ; Sur la série étendue, les écarts de X par rapport à la droite de régression calée sur la série de base ont une moyenne nulle. La moyenne quadratique E3re de ces écarts est fonction de MQIb et de l'erreur type résiduelle de régression E2rb calculée sur la série de base : E3re = (E2rb2 + (A2b x MQIb)2)0.5 (Résumé d'auteur

    Evidence of Vortex Jamming in Abrikosov Vortex Flux Flow Regime

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    We report on dynamics of non-local Abrikosov vortex flow in mesoscopic superconducting Nb channels. Magnetic field dependence of the non-local voltage induced by the flux flow shows that vortices form ordered vortex chains. Voltage asymmetry (rectification) with respect to the direction of vortex flow is evidence that vortex jamming strongly moderates vortex dynamics in mesoscopic geometries. The findings can be applied to superconducting devices exploiting vortex dynamics and vortex manipulation, including superconducting wires with engineered pinning centers.Comment: 5 pages, 3 figure

    Characterization of hormone and protein release from alpha-toxin- permeabilized chromaffin cells in primary culture

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    Addition of Staphylococcus aureus alpha-toxin to adult bovine chromaffin cells maintained in primary culture causes permeabilization of cell membrane as shown by the release of intracellular 86Rb+. The alpha-toxin does not provoke a spontaneous release of either catecholamines or chromogranin A, a protein marker of the secretory granule, showing the integrity of the secretory vesicle membrane. However the addition of micromolar free Ca2+ concentration induced the co-release of noradrenaline and chromogranin A. In alpha-toxin-treated cells, the released chromogranin A could not be sedimented and lactate dehydrogenase was still associated within cells, which provides direct evidence that secretory product is liberated by exocytosis. By contrast, permeabilization of cells with digitonin caused a Ca2+- dependent but also a Ca2+-independent release of secretory product, a dramatic loss of lactate dehydrogenase, as well as release of secretory product in a sedimentable form. Ca2+-dependent exocytosis from alpha- toxin-permeabilized cells required Mg2+-ATP and did not occur in the presence of other nucleotides. Thus alpha-toxin is a convenient tool to permeabilize chromaffin cells, and has the advantage of keeping intracellular structures, specifically the exocytotic machinery, intact

    Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers

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    Spin pumping is a mechanism that generates spin currents from ferromagnetic resonance (FMR) over macroscopic interfacial areas, thereby enabling sensitive detection of the inverse spin Hall effect that transforms spin into charge currents in non-magnetic conductors. Here we study the spin-pumping-induced voltages due to the inverse spin Hall effect in permalloy/normal metal bilayers integrated into coplanar waveguides for different normal metals and as a function of angle of the applied magnetic field direction, as well as microwave frequency and power. We find good agreement between experimental data and a theoretical model that includes contributions from anisotropic magnetoresistance (AMR) and inverse spin Hall effect (ISHE). The analysis provides consistent results over a wide range of experimental conditions as long as the precise magnetization trajectory is taken into account. The spin Hall angles for Pt, Pd, Au and Mo were determined with high precision to be 0.013±0.0020.013\pm0.002, 0.0064±0.0010.0064\pm0.001, 0.0035±0.00030.0035\pm0.0003 and 0.0005±0.0001-0.0005\pm0.0001, respectively.Comment: 11 page

    Surface spin flip probability of mesoscopic Ag wires

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    Spin relaxation in mesoscopic Ag wires in the diffusive transport regime is studied via nonlocal spin valve and Hanle effect measurements performed on permalloy/Ag lateral spin valves. The ratio between momentum and spin relaxation times is not constant at low temperatures. This can be explained with the Elliott-Yafet spin relaxation mechanism by considering the momentum surface relaxation time as being temperature dependent. We present a model to separately determine spin flip probabilities for phonon, impurity and surface scattering and find that the spin flip probability is highest for surface scattering.Comment: 5 pages, 4 figure

    Kinetic Energy Density Study of Some Representative Semilocal Kinetic Energy Functionals

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    There is a number of explicit kinetic energy density functionals for non-interacting electron systems that are obtained in terms of the electron density and its derivatives. These semilocal functionals have been widely used in the literature. In this work we present a comparative study of the kinetic energy density of these semilocal functionals, stressing the importance of the local behavior to assess the quality of the functionals. We propose a quality factor that measures the local differences between the usual orbital-based kinetic energy density distributions and the approximated ones, allowing to ensure if the good results obtained for the total kinetic energies with these semilocal functionals are due to their correct local performance or to error cancellations. We have also included contributions coming from the laplacian of the electron density to work with an infinite set of kinetic energy densities. For all the functionals but one we have found that their success in the evaluation of the total kinetic energy are due to global error cancellations, whereas the local behavior of their kinetic energy density becomes worse than that corresponding to the Thomas-Fermi functional.Comment: 12 pages, 3 figure
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