771 research outputs found

    Destination Scheduling for Secure Pinhole-Based Power-Line Communication

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    We propose an optimal destination scheduling scheme to improve the physical layer security (PLS) of a power-line communication (PLC) based Internet-of-Things system in the presence of an eavesdropper. We consider a pinhole (PH) architecture for a multi-node PLC network to capture the keyhole effect in PLC. The transmitter-to-PH link is shared between the destinations and an eavesdropper which correlates all end-to-end links. The individual channel gains are assumed to follow independent log-normal statistics. Furthermore, the additive impulsive noise at each node is modeled by an independent Bernoulli-Gaussian process. Exact computable expressions for the average secrecy capacity (ASC) and the probability of intercept (POI) performance over many different networks are derived. Approximate closed-form expressions for the asymptotic ASC and POI are also provided. We find that the asymptotic ASC saturates to a constant level as transmit power increases. We observe that the PH has an adverse effect on the ASC. Although the shared link affects the ASC, it has no effect on the POI. We show that by artificially controlling the impulsive to background noise power ratio and its arrival rate at the receivers, the secrecy performance can be improved

    Skin Substitutes

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    On tissue engineering field the research about skin substitutes represents historically the most promising approach to heal acute and chronic skin wounds, reducing requirements for donor skin autografts. Aim of this chapter is to made the state of art of the most important skin substitutes and to resume the principal tissue engineering techniques for its in vitro reconstruction. In the first part we will pay the attention to the description of the evolutive course of skin substitutes, stressing the main steps happened thanks to the important inputs coming from biotechnologies progresses and clinical practice. Since then the research in bioengineering skin, moved by clinical pressing of reconstructive and burn surgery, made progresses trying to develop cutaneous substitutes very similar to native skin by a morpho-functional point of view. So it has been possible, starting from a 2X2 cm skin human biopsy, to realize completely autologous cutaneous substitutes not only composed of two many structures of skin, dermis and epidermis, but containing also other important components: microvascular network, micro nervous network, skin immonocompetent system and melanocyte system. The final goal is to develop effective and easy handling skin substitutes that could be reproduce human skin anatomy and physiology, introducing new advantages linked to successful grafting and then to satisfactory clinical results by functional and aesthetic point of view

    High Pressure Processing Applications in Plant Foods

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    High pressure processing (HPP) is a cold pasteurization technology by which products, prepacked in their final package, are introduced to a vessel and subjected to a high level of isostatic pressure (300–600 MPa). High-pressure treatment of fruit, vegetable and fresh herb homogenate products offers us nearly fresh products in regard to sensorial and nutritional quality of original raw materials, representing relatively stable and safe source of nutrients, vitamins, minerals and health effective components. Such components can play an important role as a preventive tool against the start of illnesses, namely in the elderly. An overview of several food HPP products, namely of fruit and vegetable origin, marketed successfully around the world is presented. Effects of HPP and HPP plus heat on key spoilage and pathogenic microorganisms, including the resistant spore form and fruit/vegetable endogenous enzymes are reviewed, including the effect on the product quality. Part of the paper is devoted to the industrial equipment available for factories manufacturing HPP treated productsinfo:eu-repo/semantics/publishedVersio

    Control of near-infrared supercontinuum bandwidth by adjusting pump pulse duration

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    We experimentally and numerically investigated the impact of input pump pulse duration on the near-infrared bandwidth of supercontinuum generation in a photonic crystal fiber. We continuously stretched the temporal duration of the input pump laser (centered at 1030 nm) pulses from 500 fs up to 10 ps, while keeping fixed the pump peak power. We observed that the long-wavelength edge of the supercontinuum spectrum is increased by 200 nm as the pump pulse duration grows from 500 fs to 10 ps. We provide a quantitative fit of the experimental results by means of numerical simulations. Moreover, we have explained the observed spectral broadening enhancement induced by pump pulse energy by developing an approximate yet fully analytical model for soliton energy exchange through a series of collisions in the presence of stimulated Raman scattering

    Fungal aneurism of the right posterior inferior cerebellar artery (PICA)

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    In this case-report, the Authors show the case of a sudden death occurred in a 38-year-old woman submitted to surgical excision of a right acoustic neurinoma. At the autopsy, was detected a cerebral hemorrhage with multifocal localization by a ruptured rare fungal aneurysm of the Posterior Inferior Cerebellar Arthery (PICA). The PCR analysis, carried out on formalin-fixed paraffin-embedded tissue, identified the Aspergillus Penicillioides as the involved pathogen. We discuss the main points of infectious aneurysms, being a potential neurosurgical complication

    Spatiotemporal Characterization of Supercontinuum Extending from the Visible to the Mid-Infrared in Multimode Graded-Index Optical Fiber

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    We experimentally demonstrate that pumping a graded-index multimode fiber with sub-ns pulses from a microchip Nd:YAG laser leads to spectrally flat supercontinuum generation with a uniform bell-shaped spatial beam profile extending from the visible to the mid-infrared at 2500\,nm. We study the development of the supercontinuum along the multimode fiber by the cut-back method, which permits us to analyze the competition between the Kerr-induced geometric parametric instability and stimulated Raman scattering. We also performed a spectrally resolved temporal analysis of the supercontinuum emission.Comment: 5 pages 7 figure

    O uso de centeio como cultura intercalar em videiras.

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    bitstream/CNPT-2010/40571/1/p-co206.pd

    Opportunistic channel estimation with LTE signals of limited bandwidth for positioning applications

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    The positioning problem is interesting in a variety of applications, especially in indoor environments or in urban canyons, where the position information obtainable with traditional Global Navigation Satellite Systems is limited. In this paper, we deal with the problem of estimating, for the purposes of positioning, the time of arrival (TOA) and the angle of arrival (AOA) by processing LTE 3GPP signals, with particular attention to the uplink signals. The main contribution of this paper is the definition of new opportunistic methods to estimate the TOA and the AOA using the upstream demodulation reference signal (DM-RS) instead of the Sounding Reference Signal. We will show that the use of DM-RS and of estimation algorithms such as the Space-Alternating Generalized Expectation-Maximization and the Iterative Adaptive Approach for Amplitude and Phase estimation (IAA-APES) allows an efficient estimate of the parameters, in spite of the small, occupied bandwidth
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