831 research outputs found

    A signaling protocol for service function localization

    Get PDF
    Current proposals for chaining service functions (SFs) do not address some critical management issues, such as the discovery of SF instances close to IP data paths. This information is crucial for deploying complex services both in large cloud networks, where SFs may be moved or replicated, and in the emerging fog/mobile edge computing systems. For this purpose, in this letter, we propose the distributed off-path signaling protocol. We show the protocol functions and demonstrate its scalability and effectiveness by experimental results

    T cell subpopulations in the physiopathology of fibromyalgia : Evidence and perspectives

    Get PDF
    Fibromyalgia is one of the most important \u201crheumatic\u201d disorders, after osteoarthritis. The etiology of the disease is still not clear. At the moment, the most defined pathological mechanism is the alteration of central pain pathways, and emotional conditions can trigger or worsen symptoms. Increasing evidence supports the role of mast cells in maintaining pain conditions such as musculoskeletal pain and central sensitization. Importantly, mast cells can mediate microglia activation through the production of proinflammatory cytokines such as IL-1\u3b2, IL-6, and TNF\u251. In addition, levels of chemokines and proinflammatory cytokines are enhanced in serum and could contribute to inflammation at systemic level. Despite the well-characterized relationship between the nervous system and inflammation, the mechanism that links the different pathological features of fibromyalgia, including stress-related manifestations, central sensitization, and dysregulation of the innate and adaptive immune responses is largely unknown. This review aims to provide an overview of the current understanding of the role of adaptive immune cells, in particular T cells, in the physiopathology of fibromyalgia. It also aims at linking the latest advances emerging from basic science to envisage new perspectives to explain the role of T cells in interconnecting the psychological, neurological, and inflammatory symptoms of fibromyalgia

    Extensible Signaling Framework for Decentralized Network Management Applications

    Get PDF
    The management of network infrastructures has become increasingly complex over time, which is mainly attributed to the introduction of new functionality to support emerging services and applications. To address this important issue, research efforts in the last few years focused on developing Software-Defined Networking solutions. While initial work proposed centralized architectures, their scalability limitations have led researchers to investigate a distributed control plane, with controller placement algorithms and mechanisms for building a logically centralized network view, being examples of challenges addressed. A critical issue that has not been adequately addressed concerns the communication between distributed decision-making entities to ensure configuration consistency. To this end, this paper proposes a signaling framework that can allow the exchange of information in distributed management and control scenarios. The benefits of the proposed framework are illustrated through a realistic network resource management use case. Based on simulation, we demonstrate the flexibility and extensibility of our solution in meeting the requirements of distributed decision-making processes

    Advanced Caching for Distributing Sensor Data through Programmable Nodes

    Full text link
    This paper shows an innovative solution for distributing dynamic sensor data by using distributed caches. Our proposal is based on the concepts of service modularization and virtualization of network nodes made available by the NetServ hosting environment, which has been defined and implemented with the aim of extending the functions of the network nodes. Through a lab experiment involving tens of nodes, we have demonstrated a significant performance improvements in term of traffic saving and download time in comparison with a legacy, Internet-based, approach. Beyond this performance improvements, the proposed solution holds also functional improvements, in terms of dynamic deployment and easy integration with services making use of sensor data.Comment: Accepted for publication in IEEE LANMAN 201

    Reduced order isogeometric analysis approach for PDEs in parametrized domains

    Get PDF
    In this contribution, we coupled the isogeometric analysis to a reduced order modelling technique in order to provide a computationally efficient solution in parametric domains. In details, we adopt the free-form deformation method to obtain the parametric formulation of the domain and proper orthogonal decomposition with interpolation for the computational reduction of the model. This technique provides a real-time solution for any parameter by combining several solutions, in this case computed using isogeometric analysis on different geometrical configurations of the domain, properly mapped into a reference configuration. We underline that this reduced order model requires only the full-order solutions, making this approach non-intrusive. We present in this work the results of the application of this methodology to a heat conduction problem inside a deformable collector pipe

    Assessing the spatio-temporal spread of COVID-19 via compartmental models with diffusion in Italy, USA, and Brazil

    Full text link
    The outbreak of COVID-19 in 2020 has led to a surge in interest in the mathematical modeling of infectious diseases. Such models are usually defined as compartmental models, in which the population under study is divided into compartments based on qualitative characteristics, with different assumptions about the nature and rate of transfer across compartments. Though most commonly formulated as ordinary differential equation (ODE) models, in which the compartments depend only on time, recent works have also focused on partial differential equation (PDE) models, incorporating the variation of an epidemic in space. Such research on PDE models within a Susceptible, Infected, Exposed, Recovered, and Deceased (SEIRD) framework has led to promising results in reproducing COVID-19 contagion dynamics. In this paper, we assess the robustness of this modeling framework by considering different geometries over more extended periods than in other similar studies. We first validate our code by reproducing previously shown results for Lombardy, Italy. We then focus on the U.S. state of Georgia and on the Brazilian state of Rio de Janeiro, one of the most impacted areas in the world. Our results show good agreement with real-world epidemiological data in both time and space for all regions across major areas and across three different continents, suggesting that the modeling approach is both valid and robust.Comment: 23 pages, 19 figure

    Directional Receivers for Diffusion-Based Molecular Communications

    Get PDF
    The particle motion in diffusion-based molecular communication systems is typically modeled by using Brownian processes. In particular, this model is used to characterize the propagation of signal molecules after their release from the transmitter. This motion cannot include directionality in the propagating signal and translates into omnidirectional broadcast communications. In order to make such molecular communications system suitable for supporting communications protocols at the molecular scales, we propose to improve the receiver capabilities by introducing a form of directionality while receiving biological signals. Inspired by the directionality introduced in electromagnetic communications by means of directional antennas, we designed a nanomachine receiver having directionality properties. Our aim is to increase the average concentration of signal molecules, also referred to as carriers, in the area around the receiver surface. In this way, it is possible to increase the signal strength at the receiver. For this purpose, we propose to use a purely reflecting shell to be placed at a configurable distance from the receiver surface. The shape of the shell can be modeled as either a spherical cap or a cylinder with an empty basis. The presence of this surface causes a number of signal molecules to remain trapped in a region close to the receiver surface for a sufficiently long time. In this way, the probability of assimilating additional carriers by the compliant receptors present on the receiver surface increases. By means of an extensive simulation campaign, we identified the most suitable configuration able to provide a significant advantage with respect to those not adopting the proposed solution. The resulting approach can be regarded as an enabler of protocols for diffusive molecular communications taking advantage of directionality properties at the receiver site. It can result in an increased communication range or in improved capabilities of discriminating signals of coexisting molecular communication systems

    Laser system generating 250-mJ bunches of 5-GHz repetition rate, 12-ps pulses.

    Get PDF
    We report on a high-energy solid-state laser based on a master-oscillator power-amplifier system seeded by a 5-GHz repetition-rate mode-locked oscillator, aimed at the excitation of the dynamic Casimir effect by optically modulating a microwave resonator. Solid-state amplifiers provide up to 250 mJ at 1064 nm in a 500-ns (macro-)pulse envelope containing 12-ps (micro-)pulses, with a macro/micropulse format and energy resembling that of near-infrared free-electron lasers. Efficient second-harmonic conversion allowed synchronous pumping of an optical parametric oscillator, obtaining up to 40 mJ in the range 750-850 nm
    • 

    corecore