360 research outputs found

    Definizione dei requisiti e dell'architettura di un sistema di diagnostica per sensori radar utilizzati in ambito ferroviario

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    Il presente lavoro di tesi si colloca nell’ambito della sicurezza ferroviaria legata alla pericolosità dei passaggi a livello. Tale aspetto viene spesso sottolineato da notizie di eventi catastrofici nei quali vengono coinvolte decine di persone ogni anno. Il continuo aumento di perdite umane ha spinto gli enti gestori delle ferrovie dei paesi più industrializzati ad investire ingenti somme nello sviluppo di tecnologie per la prevenzione degli incidenti ferroviari in prossimità dei passaggi a livello. Tra tutte le innovazioni apportate nel campo della safety ferroviaria, nello svolgimento di questa tesi verrà dato risalto alle funzionalità di rilevamento ostacoli con l’ausilio della tecnologia radar. Oltre che dai vantaggi offerti dall’applicazione di questa tecnica rispetto ad altre, l’approfondimento in materia di sensori radar verrà giustificato dalla possibilità di osservarne le potenzialità su prototipi in via di sviluppo nel contesto di un progetto finanziato dalla regione Toscana. Questo progetto, noto come SIMPLE, si prefigge l’obiettivo di aumentare la sicurezza di alcuni passaggi a livello presenti sul territorio toscano utilizzando la tecnologia radar

    CLEVER: a cooperative and cross-layer approach to video streaming in HetNets

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    We investigate the problem of providing a video streaming service to mobile users in an heterogeneous cellular network composed of micro e-NodeBs (eNBs) and macro e-NodeBs (MeNBs). More in detail, we target a cross-layer dynamic allocation of the bandwidth resources available over a set of eNBs and one MeNB, with the goal of reducing the delay per chunk experienced by users. After optimally formulating the problem of minimizing the chunk delay, we detail the Cross LayEr Video stReaming (CLEVER) algorithm, to practically tackle it. CLEVER makes allocation decisions on the basis of information retrieved from the application layer aswell as from lower layers. Results, obtained over two representative case studies, show that CLEVER is able to limit the chunk delay, while also reducing the amount of bandwidth reserved for offloaded users on the MeNB, as well as the number of offloaded users. In addition, we show that CLEVER performs clearly better than two selected reference algorithms, while being very close to a best bound. Finally, we show that our solution is able to achieve high fairness indexes and good levels of Quality of Experience (QoE)

    The importance of reporting unexpected drug failure

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    Unexpected drug failure is a lack of therapeutic effect, which is not expected based on the characteristics of the drug and patient. Essentially, it may occur either for interactions (with other drugs or foods) or for biopharmaceutical issues. The risk arising from interactions is generally well characterised and physicians are well aware of it, and the importance of reporting cases of failure due to interactions is obvious. Less is known about the mechanisms and potential risk deriving from biopharmaceutical problems, and we will therefore focus on this issue. Biopharmaceutics describes the influence of the physical/chemical properties of the drug and drug product on the rate and extent of systemic drug absorption. Because after oral administration of solid pharmaceutical forms drugs must dissolve in gastrointestinal fluids before being absorbed through the intestinal epithelium, biopharmaceutical problems essentially arise from an insufficient dissolution performance. A typical situation where an insufficient dissolution may cause unexpected drug failure is when a patient is switched from one drug product to a different product. Different drug products with the same active substance may differ in manufacture and excipient composition

    S100B inhibitor pentamidine attenuates reactive gliosis and reduces neuronal loss in a mouse model of Alzheimer's disease

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    Among the different signaling molecules released during reactive gliosis occurring in Alzheimer’s disease (AD), the astrocytederived S100B protein plays a key role in neuroinflammation, one of the hallmarks of the disease. The use of pharmacological tools targeting S100B may be crucial to embank its effects and some of the pathological features of AD. The antiprotozoal drug pentamidine is a good candidate since it directly blocks S100B activity by inhibiting its interaction with the tumor suppressor p53. We used a mouse model of amyloid beta- (A-) induced AD, which is characterized by reactive gliosis and neuroinflammation in the brain, and we evaluated the effect of pentamidine on the main S100B-mediated events. Pentamidine caused the reduction of glial fibrillary acidic protein, S100B, and RAGE protein expression, which are signs of reactive gliosis, and induced p53 expression in astrocytes. Pentamidine also reduced the expression of proinflammatory mediators and markers, thus reducing neuroinflammation in AD brain. In parallel, we observed a significant neuroprotection exerted by pentamidine on CA1 pyramidal neurons. We demonstrated that pentamidine inhibits A-induced gliosis and neuroinflammation in an animal model of AD, thus playing a role in slowing down the course of the disease

    Surgical Implications of Ischemia Reperfusion Damage and Future Perspectives.

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    Flaps are often used in plastic and reconstructive surgery, and random pattern flaps were the first to be described. The indications for their use are numerous and include post-traumatic loss of su..

    What is the best spatial distribution to model base station density? A deep dive into two european mobile networks

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    This paper studies the base station (BS) spatial distributions across different scenarios in urban, rural, and coastal zones, based on real BS deployment data sets obtained from two European countries (i.e., Italy and Croatia). Basically, this paper takes into account different representative statistical distributions to characterize the probability density function of the BS spatial density, including Poisson, generalized Pareto, Weibull, lognormal, and \alpha -Stable. Based on a thorough comparison with real data sets, our results clearly assess that the \alpha -Stable distribution is the most accurate one among the other candidates in urban scenarios. This finding is confirmed across different sample area sizes, operators, and cellular technologies (GSM/UMTS/LTE). On the other hand, the lognormal and Weibull distributions tend to fit better the real ones in rural and coastal scenarios. We believe that the results of this paper can be exploited to derive fruitful guidelines for BS deployment in a cellular network design, providing various network performance metrics, such as coverage probability, transmission success probability, throughput, and delay

    an innovative algorithm to estimate risk optimum path for unmanned aerial vehicles in urban environments

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    Abstract The diffusion of the Unmanned Aerial Vehicles (UAVs) requires a suitable approach to define safe flight operations. In this paper, an innovative algorithm able to quantify the risk to the population and to search for the minimum risk path is proposed. The method has two main phases: in the former, a risk-map is generated quantifying the risk of a specific area, in the latter, a path planning algorithm seeks for the optimal path minimizing the risk. The risk-map is generated with a risk assessment method combining layers related to the population density, the sheltering factor, no-fly zones and obstacles. The risk-aware path planning is based on the well-known Optimal Rapidly-exploring Random Tree, with the minimization of the risk cost with respect to the flight time. Simulation results corroborate the validity of the approach

    Skin graft donor site: a procedure for a faster healing

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    Background: The authors want to evaluate the efficacy of fibrillary tabotamp dressing in skin graftdonor site. A comparison was made with Vaseline gauzes. Tabotamp is an absorbable haemostatic product of Ethicon (Johnson and Johnson) obtained by sterile and oxidized regenerated cellulose (Rayon). It is used for mild to moderate bleeding. Materials and methods: 276 patients were subject to skin graft and divided into two group: Group A and Group B. The donor site of patients in Group A was medicated with fibrillary tabotamp, while the patients of Group B were medicated only with Vaseline gauze. We recorded infection, timing of healing, number of dressing change, the pain felt during and after the dressing change with visual analog scale (VAS) and a questionnaire. Results: Patients allocated in Group A healed faster than the Group B. Questionnaires and VAS analysis showed lower pain felt, lower intake of pain drugs and lower infection rate in the Group A than the Group B. Analysis of coast showed lower dressing change in Group A than the Group B. Conclusion: We believe that the use of tabotamp is a very viable alternative to improve healing. (www.actabiomedica.it)

    Aerodynamic Analysis of the Aerospaceplane HYPLANE in Supersonic Rarefied Flow

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    HyPlane is the Italian aerospaceplane proposal targeting, at the same time, both the space tourism and point-to-point intercontinental hypersonic flights. Unlike other aerospaceplane projects, relying on boosters or mother airplanes that bring the vehicle to high altitude, HyPlane will take off and land horizontally from common runways. According to the current project, HyPlane will fly sub-orbital trajectories under high-supersonic/low-hypersonic continuum flow regimes. It can go beyond the von Karman line at 100 km altitude for a short time, then starting the descending leg of the trajectory. Its aerodynamic behavior up to 70 km have already been studied and the results published in previous works. In the present paper some aspects of the aerodynamic behavior of HyPlane have been analyzed at 80, 90 and 100 km. Computer tests, calculating the aerodynamic parameters, have been carried out by a Direct Simulation Monte Carlo code. The effects of the Knudsen, Mach and Reynolds numbers have been evaluated in clean configuration. The effects of the aerodynamic surfaces on the rolling, pitching and yawing moments, and therefore on the capability to control attitude, have been analyzed at h=100 km. The aerodynamic behavior has been compared also with that of another aerospaceplane at 100 km both in clean and flapped configuration
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