8,787 research outputs found
RMD (Resource Management in Diffserv) QoS-NSLP model
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
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
LC-PCN: The Load Control PCN Solution
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
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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
RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv
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
The role of organic matter in determining the distribution of pelecypods in marine sediments
Sediments in the region of Mt. Desert Island, Maine, indicate that their organic content and its state of decomposition
Surface spin flip probability of mesoscopic Ag wires
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
Characterization of hormone and protein release from alpha-toxin- permeabilized chromaffin cells in primary culture
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
Evidence of Vortex Jamming in Abrikosov Vortex Flux Flow Regime
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
Utilisation des incertitudes associées aux mesures altimétriques satellitaires de plan d'eau
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
Molecular evidence for increased regulatory conservation during metamorphosis, and against deleterious cascading effects of hybrid breakdown in Drosophila
<p>Abstract</p> <p>Background</p> <p>Speculation regarding the importance of changes in gene regulation in determining major phylogenetic patterns continues to accrue, despite a lack of broad-scale comparative studies examining how patterns of gene expression vary during development. Comparative transcriptional profiling of adult interspecific hybrids and their parental species has uncovered widespread divergence of the mechanisms controlling gene regulation, revealing incompatibilities that are masked in comparisons between the pure species. However, this has prompted the suggestion that misexpression in adult hybrids results from the downstream cascading effects of a subset of genes improperly regulated in early development.</p> <p>Results</p> <p>We sought to determine how gene expression diverges over development, as well as test the cascade hypothesis, by profiling expression in males of <it>Drosophila melanogaster</it>, <it>D. sechellia</it>, and <it>D. simulans</it>, as well as the <it>D. simulans </it>(♀) × <it>D. sechellia </it>(♂) male F1 hybrids, at four different developmental time points (3rd instar larval, early pupal, late pupal, and newly-emerged adult). Contrary to the cascade model of misexpression, we find that there is considerable stage-specific autonomy of regulatory breakdown in hybrids, with the larval and adult stages showing significantly more hybrid misexpression as compared to the pupal stage. However, comparisons between pure species indicate that genes expressed during earlier stages of development tend to be more conserved in terms of their level of expression than those expressed during later stages, suggesting that while Von Baer's famous law applies at both the level of nucleotide sequence and expression, it may not apply necessarily to the underlying overall regulatory network, which appears to diverge over the course of ontogeny and which can only be ascertained by combining divergent genomes in species hybrids.</p> <p>Conclusion</p> <p>Our results suggest that complex integration of regulatory circuits during morphogenesis may lead to it being more refractory to divergence of underlying gene regulatory mechanisms - more than that suggested by the conservation of gene expression levels between species during earlier stages. This provides support for a 'developmental hourglass' model of divergence of gene expression in <it>Drosophila </it>resulting in a highly conserved pupal stage.</p
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