838 research outputs found

    A Low Cost Ultrasound-based Localisation System

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    This paper presents a low-cost localisation system based on ultrasonic sensing and time of flight measurements. A compact ultrasound emitter has been designed to generate omnidirectional train of ultrasound pulses which are then picked up by several fixed receivers measuring the time difference of arrival. A least squares approach is used to analytically obtain a first estimate of the emitter position, which is then refined through steepest descent optimisation. All processing is done via a standard Arduino platform, proving the low computational demands of the method. Localisation results are validated against a state-of-the-art Optitrack motion capture system. It is shown that the system can cover a 4.3x3.1m arena with a mean error localisation error of 1.57cm and an average standard deviation of 1.39cm throughout the arena

    Datacenter optimization methods for Softwarized Network Services

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    This paper tackles the problem of optimum Virtual Machine placement, focusing on an industrial use-case dealing with capacity planning for Virtualized Network Functions. The work is framed within an industrial collaboration with the Vodafone network operator, where a particularly important problem is the one of optimum deployment of Softwarized Network Functions within their Virtualized Networking Infrastructure, spanning across several EU countries. The problem is particularly difficult due to the presence of a multitude of placement constraints that are needed in the industrial use-case, including soft affinity constraints, that should be respected only as secondary objective; furthermore, in some EU regions, the size of the problem makes it unfeasible to solve it with traditional MILP-based techniques. In this work, we review and address limitations of previously proposed heuristics for this kind of problems, and propose a new placement strategy that is shown experimentally to be more effective in dealing with soft affinity constraints. The paper includes an extensive experimental evaluation encompassing a multitude of optimization strategies, applied to a set of problems including both real-world problems that we made available as an open data-set, and additional randomly generated problems mimicking the structure of the original real-world problems

    Network Orchestration in Reliable 5G/NFV/SDN Infrastructures

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    In this paper, we elaborate an SDN orchestration solution aiming at the dynamic adaptation of service chain paths thereby addressing high-availability requirements of 5G applications. We present an SDN orchestrator that periodically monitors the availability of the network and, if necessary, promptly adapts service chain paths to recover from congestion events and to preserve network QoS performance of service data flows. A set of performance results are finally presented.This work has been partially supported by the EU H2020 5G Exchange (5GEx) innovation project (grant no. 671636) and by EU H2020 5G-Transformer Project (grant no. 761536

    Widening use of dexamethasone implant for the treatment of macular edema

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    Sustained-release intravitreal 0.7 mg dexamethasone (DEX) implant is approved in Europe for the treatment of macular edema related to diabetic retinopathy, branch retinal vein occlusion, central retinal vein occlusion, and non-infectious uveitis. The implant is formulated in a biodegradable copolymer to release the active ingredient within the vitreous chamber for up to 6 months after an intravitreal injection, allowing a prolonged interval of efficacy between injections with a good safety profile. Various other ocular pathologies with inflammatory etio­pathogeneses associated with macular edema have been treated by DEX implant, including neovascular age-related macular degeneration, Irvine–Gass syndrome, vasoproliferative retinal tumors, retinal telangiectasia, Coats’ disease, radiation maculopathy, retinitis pigmentosa, and macular edema secondary to scleral buckling and pars plana vitrectomy. We undertook a review to provide a comprehensive collection of all of the diseases that benefit from the use of the sustained-release DEX implant, alone or in combination with concomitant therapies. A MEDLINE search revealed lack of randomized controlled trials related to these indications. Therefore we included and analyzed all available studies (retrospective and prospective, com­parative and non-comparative, randomized and nonrandomized, single center and multicenter, and case report). There are reports in the literature of the use of DEX implant across a range of macular edema-related pathologies, with their clinical experience supporting the use of DEX implant on a case-by-case basis with the aim of improving patient outcomes in many macular pathologies. As many of the reported macular pathologies are difficult to treat, a new treat­ment option that has a beneficial influence on the clinical course of the disease may be useful in clinical practice

    Modeling microevolution in a changing environment: The evolving quasispecies and the Diluted Champion Process

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    Several pathogens use evolvability as a survival strategy against acquired immunity of the host. Despite their high variability in time, some of them exhibit quite low variability within the population at any given time, a somehow paradoxical behavior often called the evolving quasispecies. In this paper we introduce a simplified model of an evolving viral population in which the effects of the acquired immunity of the host are represented by the decrease of the fitness of the corresponding viral strains, depending on the frequency of the strain in the viral population. The model exhibits evolving quasispecies behavior in a certain range of its parameters, ans suggests how punctuated evolution can be induced by a simple feedback mechanism.Comment: 15 pages, 12 figures. Figures redrawn, some additional clarifications in the text. To appear in Journal of Statistical Mechanics: Theory and Experimen

    Seed morphobiometry of wild and cultivated taxa of Phaseolus L. (Fabaceae)

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    A morphobiometric analysis of seeds of Phaseolus L. from 50 populations belonging to 31 wild and cultivated taxa was carried out. Based on the outcome of the study an identifi cation key was developed comprising 25 morphotypes of which 23 related to individual taxa The different patterns of seminal tegument allowed 31 taxa to cluster into three groups: (1) Phaseolus angustissimus Gray group (wrinkled seed coat) with two morphotypes, (2) Phaseolus lunatus L. group (smooth tegument with striae) with ten morphotypes and (3) Phaseolus vulgaris L. group (smooth tegument without striae) with 13 morphotypes. All the taxa exhibited uniformity in size and variability in tegument colour of seeds irrespective of the source of population and the type of habitat. Characterization of taxa into defi nite morphotypes and the groups could be useful for biosystematic investigations and the markerbased genetic selection approaches in this important leguminous crop
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