221 research outputs found

    Evaluator services for optimised service placement in distributed heterogeneous cloud infrastructures

    Get PDF
    Optimal placement of demanding real-time interactive applications in a distributed heterogeneous cloud very quickly results in a complex tradeoff between the application constraints and resource capabilities. This requires very detailed information of the various requirements and capabilities of the applications and available resources. In this paper, we present a mathematical model for the service optimization problem and study the concept of evaluator services as a flexible and efficient solution for this complex problem. An evaluator service is a service probe that is deployed in particular runtime environments to assess the feasibility and cost-effectiveness of deploying a specific application in such environment. We discuss how this concept can be incorporated in a general framework such as the FUSION architecture and discuss the key benefits and tradeoffs for doing evaluator-based optimal service placement in widely distributed heterogeneous cloud environments

    Service oriented networking

    Get PDF
    This paper introduces a new paradigm for service oriented networking being developed in the FUSION project(1). Despite recent proposals in the area of information centric networking, a similar treatment of services - where networked software functions, rather than content, are dynamically deployed, replicated and invoked - has received little attention by the network research community to date. Our approach provides the mechanisms required to deploy a replicated service instance in the network and to route client requests to the closest instance in an efficient manner. We address the main issues that such a paradigm raises including load balancing, resource registration, domain monitoring and inter-domain orchestration. We also present preliminary evaluation results of current work

    Service-centric networking

    Get PDF
    This chapter introduces a new paradigm for service centric networking. Building upon recent proposals in the area of information centric networking, a similar treatment of services – where networked software functions, rather than content, are dynamically deployed, replicated and invoked – is discussed. Service-centric networking provides the mechanisms required to deploy replicated service instances across highly distributed networked cloud infrastructures and to route client requests to the closest instance while providing more efficient network infrastructure usage, improved QoS and new business opportunities for application and service providers. </jats:p

    Wine industry perceptions and reactions to the COVID-19 crisis in the Old and New Worlds: Do business models make a difference?

    Get PDF
    The COVID-19 crisis has severely impacted the wine industry, with producers in different countries affected differently and, therefore, differing in their perceptions toward it. These differing perceptions are assumed to be due to different business models, mainly linked to the distribution system adopted and resulting in varying distances of producers to distributors and consumers. While upstream integration characterizes the Old World, the New World applies a downstream business model, being more closely linked to distributors and consumers and, therefore, more vulnerable to shocks, which should lead to higher perceived impacts of the COVID-19 crisis. This study analyzes 542 surveys collected from wineries in nine countries, divided into New World, historical Old World, and emerging Old World. Econometric results show statistically significant differences in both the perceived impact of COVID-19 and wineries'' responses in terms of planned investments, with the New World being more affected. A common desire by wineries to direct future investments towards direct-to-consumer sales and communication was found, to the detriment of investments in vineyards and cellars. This desire is particularly strong in the New World, in line with their focus on the downstream part of the value chain, underlying their greater reactivity to shocks and capacity to innovate. EconLit Citations: [D22; L21; L66; Q13]

    Vlasov moments, integrable systems and singular solutions

    Full text link
    The Vlasov equation for the collisionless evolution of the single-particle probability distribution function (PDF) is a well-known Lie-Poisson Hamiltonian system. Remarkably, the operation of taking the moments of the Vlasov PDF preserves the Lie-Poisson structure. The individual particle motions correspond to singular solutions of the Vlasov equation. The paper focuses on singular solutions of the problem of geodesic motion of the Vlasov moments. These singular solutions recover geodesic motion of the individual particles.Comment: 16 pages, no figures. Submitted to Phys. Lett.

    Computational and Mathematical Modelling of the EGF Receptor System

    Get PDF
    This chapter gives an overview of computational and mathematical modelling of the EGF receptor system. It begins with a survey of motivations for producing such models, then describes the main approaches that are taken to carrying out such modelling, viz. differential equations and individual-based modelling. Finally, a number of projects that applying modelling and simulation techniques to various aspects of the EGF receptor system are described

    Observation and characterization of laser-driven Phase Space Electron Holes

    Get PDF
    The direct observation and full characterization of a Phase Space Electron Hole (EH) generated by laser-matter interaction is presented. This structure has been detected via proton radiography during the interaction between an intense laser pulse (t=1ns temporally flat-top, I= 10^14W/cm^2) and a gold 26 micron thick hohlraum. This technique has allowed us the simultaneous detection of propagation velocity, potential and electron density spatial profile across the EH with fine spatial and temporal resolution providing an unprecedentedly detailed experimental characterization

    Activation of the B cell receptor leads to increased membrane proximity of the Igα cytoplasmic domain.

    Get PDF
    Binding of antigen to the B cell receptor (BCR) induces conformational changes in BCR's cytoplasmic domains that are concomitant with phosphorylation of the immunoreceptor tyrosine-based activation motifs (ITAMs). Recently, reversible folding of the CD3ε and ξ chain ITAMs into the plasma membrane has been suggested to regulate T cell receptor signaling. Here we show that the Igα and Igβ cytoplasmic domains of the BCR do not associate with plasma membrane in resting B cells. However, antigen binding and ITAM phosphorylation specifically increased membrane proximity of Igα, but not Igβ. Thus, BCR activation is accompanied by asymmetric conformational changes, possibly promoting the binding of Igα and Igβ to differently localized signaling complexes

    Modulational Instability in Equations of KdV Type

    Full text link
    It is a matter of experience that nonlinear waves in dispersive media, propagating primarily in one direction, may appear periodic in small space and time scales, but their characteristics --- amplitude, phase, wave number, etc. --- slowly vary in large space and time scales. In the 1970's, Whitham developed an asymptotic (WKB) method to study the effects of small "modulations" on nonlinear periodic wave trains. Since then, there has been a great deal of work aiming at rigorously justifying the predictions from Whitham's formal theory. We discuss recent advances in the mathematical understanding of the dynamics, in particular, the instability of slowly modulated wave trains for nonlinear dispersive equations of KdV type.Comment: 40 pages. To appear in upcoming title in Lecture Notes in Physic
    corecore