886 research outputs found

    Time Aware Knowledge Extraction for Microblog Summarization on Twitter

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    Microblogging services like Twitter and Facebook collect millions of user generated content every moment about trending news, occurring events, and so on. Nevertheless, it is really a nightmare to find information of interest through the huge amount of available posts that are often noise and redundant. In general, social media analytics services have caught increasing attention from both side research and industry. Specifically, the dynamic context of microblogging requires to manage not only meaning of information but also the evolution of knowledge over the timeline. This work defines Time Aware Knowledge Extraction (briefly TAKE) methodology that relies on temporal extension of Fuzzy Formal Concept Analysis. In particular, a microblog summarization algorithm has been defined filtering the concepts organized by TAKE in a time-dependent hierarchy. The algorithm addresses topic-based summarization on Twitter. Besides considering the timing of the concepts, another distinguish feature of the proposed microblog summarization framework is the possibility to have more or less detailed summary, according to the user's needs, with good levels of quality and completeness as highlighted in the experimental results.Comment: 33 pages, 10 figure

    Bombay hypertopologies

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    [EN] Recently it was shown that, in a metric space, the upper Wijsman convergence can be topologized with the introduction of a new far-miss topology. The resulting Wijsman topology is a mixture of the ball topology and the proximal ball topology. It leads easily to the generalized or g-Wijsman topology on the hyperspace of any topological space with a compatible LO-proximity and a cobase (i.e. a family of closed subsets which is closed under finite unions and which contains all singletons). Further generalization involving a topological space with two compatible LO-proximities and a cobase results in a new hypertopology which we call the Bombay topology. The generalized locally finite Bombay topology includes the known hypertopologies as special cases and moreover it gives birth to many new hypertopologies. We show how it facilitates comparison of any two hypertopologies by proving one simple result of which most of the existing results are easy consequences.Di Maio, G.; Meccariello, E.; Naimpally, S. (2003). Bombay hypertopologies. Applied General Topology. 4(2):421-444. doi:10.4995/agt.2003.2042.SWORD4214444

    Graph topologies on closed multifunctions

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    [EN] In this paper we study function space topologies on closed multifunctions, i.e. closed relations on X x Y using various hypertopologies. The hypertopologies are in essence, graph topologies i.e topologies on functions considered as graphs which are subsets of X x Y . We also study several topologies, including one that is derived from the Attouch-Wets filter on the range. We state embedding theorems which enable us to generalize and prove some recent results in the literature with the use of known results in the hyperspace of the range space and in the function space topologies of ordinary functions.Di Maio, G.; Meccariello, E.; Naimpally, S. (2003). Graph topologies on closed multifunctions. Applied General Topology. 4(2):445-465. doi:10.4995/agt.2003.2044.SWORD4454654

    Redox sensitivity of tyrosine hydroxylase activity and expression in dopaminergic dysfunction

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    Oxidant molecules generated during neuronal metabolism appear to play a significant role in the processes of aging and neurodegeneration. Increasing experimental evidence suggests the noteworthy relevance of the intracellular reduction-oxidation (redox) balance for the dopaminergic (DA-ergic) neurons of the substantia nigra pars compacta. These cells possess a distinct physiology intrinsically associated with elevated reactive oxygen species production, conferring on them a high vulnerability to free radical damage, one of the major causes of selective DA-ergic neuron dysfunction and degeneration related to neurological disorders such as Parkinson’s disease. Tyrosine hydroxylase (tyrosine 3-monooxygenase; E.C. 1.14.16.2; TH) activity represents the rate-limiting biochemical event in DA synthesis. TH activity, metabolism and expression are finely tuned by several regulatory systems in order to maintain a crucial physiological condition in which DA synthesis is closely coupled to its secretion. Alterations of these regulatory systems of TH functions have indeed been thought to be key events in the DA-ergic degeneration. TH has seven cysteine residues presenting thiols. Depending on the oxido-reductive (redox) status of the cellular environment, thiols exist either in the reduced form of free thiols or oxidized to disulfides. The formation of disulfides in proteins exerts critical regulatory functions both in physiological and in pathological conditions when oxidative stress is sustained. Several reports have recently shown that redox state changes of thiol residues, as consequence of an oxidative injury, can directly or indirectly affect the TH activity, metabolism and expression. The major focus of this review, therefore, is to report recent evidence on the redox modulation of TH activity and expression, and to provide an overview of a cellular phenomenon that might represent a target for new therapeutic strategies against the DA-ergic neurodegenerative disorders.peer-reviewe

    HISTORICAL RECONSTRUCTION OF FISHERY CATCHES FOR THE LAKE GARDA

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    Fishery activities in the Garda lake had historically played a very important role for the people living along the coasts of the lake. In this work we present updated time series of catches, that could be useful to describe the evolution of the fishery, linking landings with the changes of environmental conditions and biological communities reported in the literature. Total catches peaked in the mid ’60s (ca. 700 metric tons) and then smoothly decreased until the ‘90s, when they started oscillating around a total production of about 400 metric tonnes, similarly to the situation observed before the ‘50s. However, catches composition shows more complex dynamics over time, with the disappearance over the years of species very important for the lake ecosystem and for the fishery itself, both in terms of catches or economic value (e.g. the Common bleak Alburnus alborella or the Carpione del Garda Salmo carpio). Even if some of the zooplankivourous species showed strong declines over time, this feeding category has always been very important for the lake fishery, representing at least 50% of the total caught biomass and reaching more than 80% of total catches since 1980. This is due to the large contribution of the Agone Alosa agone, that has been very important in the whole history of the fishery of the lake, and of the European whitefish Coregonus lavaretus, whose contribution changed over the decades, but that is characterized by an increase in the last period, becoming the most important species during the last decade

    MSF: An Efficient Mobile Phone Sensing Framework

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    Recent evolutions in smartphones, today provided with several sensors, have the strong processing capabilities needed to extract from raw sensed data sensor meaningful high-level views of the physical context around the user. A new promising research area called mobile sensing promotes completely decentralized sensing based on smartphone capabilities only. However, current mobile sensing solutions are not very mature; yet, because they are based on ad hoc software solutions tailored to one specific technical problem (e.g., power management, resource locking, etc.), they are difficult to reuse and integrate in different projects, and they do not focus on the performance efficiency of the monitoring support. To overcome those limitations, this paper proposes Mobile Sensing Framework (MSF), a flexible platform to ease the development of mobile sensing applications through the definition of a common set of facilities that mask all low-level technical details in reading and processing raw sensor data. MSF has been optimized also to enhance performances for Android-based systems, and we report an extensive set of experimental results that assess our architecture and quantitatively compare it with a selection of other mobile sensing systems by showing that MSF outperforms them by presenting lower CPU usage and memory footprints

    Quantum Computation of Thermal Averages for a Non-Abelian D4D_4 Lattice Gauge Theory via Quantum Metropolis Sampling

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    In this paper, we show the application of the Quantum Metropolis Sampling (QMS) algorithm to a toy gauge theory with discrete non-Abelian gauge group D4D_4 in (2+1)-dimensions, discussing in general how some components of hybrid quantum-classical algorithms should be adapted in the case of gauge theories. In particular, we discuss the construction of random unitary operators which preserve gauge invariance and act transitively on the physical Hilbert space, constituting an ergodic set of quantum Metropolis moves between gauge invariant eigenspaces, and introduce a protocol for gauge invariant measurements. Furthermore, we show how a finite resolution in the energy measurements distorts the energy and plaquette distribution measured via QMS, and propose a heuristic model that takes into account part of the deviations between numerical results and exact analytical results, whose discrepancy tends to vanish by increasing the number of qubits used for the energy measurements.Comment: 19 pages, 21 figure
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