3,653 research outputs found

    A Chemistry-Inspired Framework for Achieving Consensus in Wireless Sensor Networks

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    The aim of this paper is to show how simple interaction mechanisms, inspired by chemical systems, can provide the basic tools to design and analyze a mathematical model for achieving consensus in wireless sensor networks, characterized by balanced directed graphs. The convergence and stability of the model are first proven by using new mathematical tools, which are borrowed directly from chemical theory, and then validated by means of simulation results, for different network topologies and number of sensors. The underlying chemical theory is also used to derive simple interaction rules that may account for practical issues, such as the estimation of the number of neighbors and the robustness against perturbations. Finally, the proposed chemical solution is validated under real-world conditions by means of a four-node hardware implementation where the exchange of information among nodes takes place in a distributed manner (with no need for any admission control and synchronism procedure), simply relying on the transmission of a pulse whose rate is proportional to the state of each sensor.Comment: 12 pages, 10 figures, submitted to IEEE Sensors Journa

    Numerical simulations of mountain winds in an alpine valley

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    The meteorological model WRF is used to investigate the wind circulation in Valle Camonica, Italy, an alpine valley that includes a large subalpine lake. The aim was to obtain the information necessary to evaluate the wind potential of this area and, from a methodological point of view, to suggest how numerical modeling can be used to locate the most interesting spots for wind exploitation. Two simulations are carried out in order to analyze typical scenarios occurring in the valley. In the first one, the diurnal cycle of thermally-induced winds generated by the heating-cooling of the mountain range encircling the valley is analyzed. The results show that the mountain slopes strongly affect the low-level winds during both daytime and nighttime, and that the correct setting of the lake temperature improves the quality of the meteorological fields provided by WRF significantly. The second simulation deals with an event of strong downslope winds caused by the passage of a cold front. Comparisons between simulated and measured wind speed, direction and air temperature are also shown

    Dense bidisperse suspensions under non-homogenous shear

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    We study the rheological behaviour of bidisperse suspensions in three dimensions under a non-uniform shear flow, made by the superimposition of a linear shear and a sinusoidal disturbance. Our results show that i) only a streamwise disturbance in the shear-plane alters the suspension dynamics by substantially reducing the relative viscosity, ii) with the amplitude of the disturbance determining a threshold value for the effect to kick-in and its wavenumber controlling the amount of reduction and which of the two phases is affected. We show that, iii) the rheological changes are caused by the effective separation of the two phases, with the large or small particles layering in separate regions. We provide a physical explanation of the phase separation process and of the conditions necessary to trigger it. We test the results in the whole flow curve, and we show that the mechanism remains substantially unaltered, with the only difference being the nature of the interactions between particles modified by the phase separation

    Production cost model of the multi-jet-fusion technology

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    ¬© IMechE 2019. The paper presents a model of the production costs of the multi-jet-fusion technology that is based on a model of production costs of the selective laser sintering technology. The model is developed using the methodology of analysis of the event-driven process chain, which consists of modeling, batch assembly, setup, building, removal, and blasting activities. Production costs of each of the activities are separated to direct (labor, material, and energy) costs and indirect (equipment, overheads, and other indirect) costs. The developed model represents a basis for the development of algorithms and software tools for the calculation of the production costs of the multi-jet-fusion technology, since it defines all the necessary inputs and calculation procedures that enable the calculation of the total costs of a batch of products. Besides, the paper presents a procedure for the estimation of production costs that are attributed to a single product or product type.The authors wish to acknowledge the support of European Commission through the project ‚ÄúAdvanced design rules for optimal dynamic properties of additive manufacturing products ‚Äď A_MADAM‚ÄĚ, which has received funding from the European Union‚Äôs Horizon 2020 research and innovation programme under the Marie SkŇāodowska-Curie grant agreement No 734455

    D-mannose: a promising support for acute urinary tract infections in women. A pilot study

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    Urinary tract infections still represent a significant bother for women and result in high costs to the health system. D-mannose is a simple sugar; it seems able to hinder bacteria adhesion to the urothelium. The present study aimed to determine whether D-mannose alone is effective in treating acute urinary tract infections in women and its possible utility in the management of recurrences

    Characterization of DNA methylation as a function of biological complexity via dinucleotide inter-distances

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    We perform a statistical study of the distances between successive occurrencies of a given dinucleotide in the DNA sequence for a number of organisms of different complexity. Our analysis highlights peculiar features of the dinucleotide CG distribution in mammalian DNA, pointing towards a connection with the role of such dinucleotide in DNA methylation. While the CG distributions of mammals exhibit exponential tails with comparable parameters, the picture for the other organisms studied (e.g., fish, insects, bacteria and viruses) is more heterogeneous, possibly because in these organisms DNA methylation has different functional roles. Our analysis suggests that the distribution of the distances between dinucleotides CG provides useful insights in characterizing and classifying organisms in terms of methylation functionalities.Comment: 13 pages, 5 figures. To be published in the Philosophical Transactions A theme issue "DNA as information

    Evoluzione con la distanza delle proprietà non termiche degli ammassi di galassie

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    Questo percorso di tesi affronta lo studio dell'emissione radio da parte di aloni presenti in ammassi di galassie - ossia le strutture massive pi√Ļ estese dell'Universo in equilibrio viriale - a diversi valori di redshift, per indagare se e come le propriet√† degli ammassi si distinguano a seconda della diversa distanza da noi. E' stato considerato un campione di ammassi catalogati fino al 2018, integrando un campione precedente risalente al 2011, per un totale di 83 ammassi in fase di merger con aloni radio al centro. In termini della potenza radio, della luminosit√† in X e della massima dimensione lineare radio non si evince una netta separazione in funzione dei redshift; tuttavia, gli aloni radio a redshift maggiori di z=0.30 presentano valori di potenza, luminosit√† in X e dimensione tendenzialmente maggiori rispetto agli aloni a redshift minori di z=0.30. Un ulteriore allargamento del campione e il miglioramento della sensibilit√† degli strumenti di osservazione consentiranno una analisi statistica pi√Ļ approfondita e dettagliata
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