1,212 research outputs found

    The Dynamic Phase Transition for Decoding Algorithms

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    The state-of-the-art error correcting codes are based on large random constructions (random graphs, random permutations, ...) and are decoded by linear-time iterative algorithms. Because of these features, they are remarkable examples of diluted mean-field spin glasses, both from the static and from the dynamic points of view. We analyze the behavior of decoding algorithms using the mapping onto statistical-physics models. This allows to understand the intrinsic (i.e. algorithm independent) features of this behavior.Comment: 40 pages, 29 eps figure

    Asynchronous Distributed Execution of Fixpoint-Based Computational Fields

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    Coordination is essential for dynamic distributed systems whose components exhibit interactive and autonomous behaviors. Spatially distributed, locally interacting, propagating computational fields are particularly appealing for allowing components to join and leave with little or no overhead. Computational fields are a key ingredient of aggregate programming, a promising software engineering methodology particularly relevant for the Internet of Things. In our approach, space topology is represented by a fixed graph-shaped field, namely a network with attributes on both nodes and arcs, where arcs represent interaction capabilities between nodes. We propose a SMuC calculus where mu-calculus- like modal formulas represent how the values stored in neighbor nodes should be combined to update the present node. Fixpoint operations can be understood globally as recursive definitions, or locally as asynchronous converging propagation processes. We present a distributed implementation of our calculus. The translation is first done mapping SMuC programs into normal form, purely iterative programs and then into distributed programs. Some key results are presented that show convergence of fixpoint computations under fair asynchrony and under reinitialization of nodes. The first result allows nodes to proceed at different speeds, while the second one provides robustness against certain kinds of failure. We illustrate our approach with a case study based on a disaster recovery scenario, implemented in a prototype simulator that we use to evaluate the performance of a recovery strategy

    Teatro romano di Vallebuona a Volterra. Proposta di musealizzazione del sito archeologico

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    Il progetto della tesi è una proposta che rappresenta l'ipotesi di valorizzare un monumento dal grande valore storico, sociale, culturale, attraverso la sua reintroduzione nel contesto attivo e dinamico della vita contemporanea. Nel caso del teatro romano di Volterra, l'ipotesi progettuale prevede il riutilizzo dello stesso per mezzo di una strategia che lo renda disponibile sia come grande spazio per eventi sia come luogo eminente per la conoscenza delle radici culturali della città. Il presupposto cardine dell'intero intervento è quello secondo cui la valorizzazione del patrimonio storico, così come la sua trasmissione, debbano necessariamente passare attraverso un utilizzo che sia in grado di innescare un interesse culturale che non si limiti al semplice nozionismo "ingenuo" ma che vivifichi l'attività che in tali monumenti viene svolta

    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 “Advanced design rules for optimal dynamic properties of additive manufacturing products – A_MADAM”, which has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 734455

    An integrated study of the biodiversity within the Pseudechiniscus suillus-facettalis group (Heterotardigrada:Echiniscidae):Echiniscidae)

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    Pseudechiniscus is the second most species-rich genus in Heterotardigrada and in the family Echiniscidae. However, previous studies have pointed out polyphyly and heterogeneity in this taxon. The recent erection of the genus Acanthechiniscus was another step in making Pseudechiniscus monophyletic, but species identification is still problematic. The present investigation aims at clarifying biodiversity and taxonomy of Pseudechiniscus taxa, with a special focus on species pertaining to the so-called \u2018suillus\u2013facettalis group\u2019, by using an integrated approach of morphological and molecular investigations. The analysis of sequences from specimens sampled in Europe and Asia confirms the monophyly of the genus Pseudechiniscus. Inside the genus, two main evolutionary lineages are recognizable: the P. novaezeelandiae lineage and the P. suillus\u2013facettalis group lineage. Inside the P. suillus\u2013facettalis group, COI molecular data points out a very high variability between sampled localities, but in some cases also among specimens sampled in the same locality (up to 33.3% p-distance). The integrated approach to the study of Pseudechiniscus allows confirmation of its monophyly and highlights the relationships in the taxon, pointing to its global distribution

    A Decidable Characterization of a Graphical Pi-calculus with Iterators

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    This paper presents the Pi-graphs, a visual paradigm for the modelling and verification of mobile systems. The language is a graphical variant of the Pi-calculus with iterators to express non-terminating behaviors. The operational semantics of Pi-graphs use ground notions of labelled transition and bisimulation, which means standard verification techniques can be applied. We show that bisimilarity is decidable for the proposed semantics, a result obtained thanks to an original notion of causal clock as well as the automatic garbage collection of unused names.Comment: In Proceedings INFINITY 2010, arXiv:1010.611

    In vitro probiotic properties and in vivo anti-ageing effects of Lactoplantibacillus plantarum PFA2018AU strain isolated from carrots on Caenorhabditis elegans

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    Lactic acid bacteria (LAB) share and provide several beneficial effects on human health, such as the release of bioactive metabolites, pathogen competition, and immune stimulation. The two major reservoirs of probiotic microorganisms are the human gastro-intestinal tract and fermented dairy products. However, other sources, such as plant-based foods, represent important alternatives thanks to their large distribution and nutritive value. Here, the probiotic potential of autochthonous Lactiplantibacillus plantarum PFA2018AU, isolated from carrots harvested in Fucino highland, Abruzzo (Italy), was investigated through in vitro and in vivo approaches. The strain was sent to the biobank of Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna in Italy for the purpose of patent procedures under the Budapest Treaty. The isolate showed high survival capability under in vitro simulated gastro-intestinal conditions, antibiotic susceptibility, hydrophobicity, aggregation, and the ability to inhibit the in vitro growth of Salmonella enterica serovar Typhimurium, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus pathogens. Caenorhabditis elegans was used as the in vivo model in order to analyse prolongevity and anti-ageing effects. L. plantarum PFA2018AU significantly colonised the gut of the worms, extended their lifespan, and stimulated their innate immunity. Overall, these results showed that autochthonous LAB from vegetables, such as carrots, have functional features that can be considered novel probiotic candidates

    Terahertz absorption-saturation and emission from electron-doped germanium quantum wells

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    We study radiative relaxation at terahertz frequencies in n-type Ge/SiGe quantum wells, optically pumped with a terahertz free electron laser. Two wells coupled through a tunneling barrier are designed to operate as a three-level laser system with non-equilibrium population generated by optical pumping around the 1→3 intersubband transition at 10 THz. The non-equilibrium subband population dynamics are studied by absorption-saturation measurements and compared to a numerical model. In the emission spectroscopy experiment, we observed a photoluminescence peak at 4 THz, which can be attributed to the 3→2 intersubband transition with possible contribution from the 2→1 intersubband transition. These results represent a step towards silicon-based integrated terahertz emitters
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