12,428 research outputs found

    Convergence to the Critical Attractor at Infinite and Tangent Bifurcation Points

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    The dynamics of the convergence to the critical attractor for the logistic map is investigated. At the border of chaos, when the Liapunov exponent is zero, the use of the non-extensive statistical mechanics formalism allows to define a weak sensitivity or insensitivity to initial conditions. Using this formalism we analyse how a set of initial conditions spread all over the phase space converges to the critical attractor in the case of infinite bifurcation and tangent bifurcation points. We show that the phenomena is governed in both cases by a power-law regime but the critical exponents depend on the type of bifurcation and may also depend on the numerical experiment set-up. Differences and similarities between the two cases are also discussed.Comment: 5 figures, accepted for publication in Int. J. of Bifurcation and Chaos (July 2006

    Numerical Study of the Oscillatory Convergence to the Attractor at the Edge of Chaos

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    This paper compares three different types of ``onset of chaos'' in the logistic and generalized logistic map: the Feigenbaum attractor at the end of the period doubling bifurcations; the tangent bifurcation at the border of the period three window; the transition to chaos in the generalized logistic with inflection 1/2 (xn+1=μxn1/2x_{n+1} = \mu x_{n}^{1/2}), in which the main bifurcation cascade, as well as the bifurcations generated by the periodic windows in the chaotic region, collapse in a single point. The occupation number and the Tsallis entropy are studied. The different regimes of convergence to the attractor, starting from two kinds of far-from-equilibrium initial conditions, are distinguished by the presence or absence of log-log oscillations, by different power-law scalings and by a gap in the saturation levels. We show that the escort distribution implicit in the Tsallis entropy may tune the log-log oscillations or the crossover times.Comment: 10 pages, 5 figure

    Fractures and lineaments of Sicily Island: Preliminary results on analog optical techniques

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    There are no author-identified significant results in this report

    Results of Skylab investigation over Italy

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    The author has identified the following significant results. Multispectral high resolution photography of S190A was successfully applied to the detection of paleoriverbeds in flat lands. Results of SL-3 mission were compared to those of LANDSAT for two regional geological surveys (linear structures) on the islands of Sicily and Sardinia. On Sicily, the seasonal conditions were unfavorable for Skylab while LANDSAT played a major role in discovering long, unknown lineaments of great interest for the geodynamics of the area. On Sardinia, owing to the vegetation type and to the geomorphic conditions, the Skylab imagery was successfully employed to describe the network of linears, both regional and local. Results can be used to study the relationship between linears, actual fracturing and the occurrence of mineral deposits

    Dante's Inferno and the McGill Pain Questionnaire

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    Aims of the study: To study the images which depict the damned's sufferings in Dante's Inferno, in their expression of the several meanings of "pain", the semantics of "pain" in the poem has been analyzed, eventually trying to determine whether the organization of punishments of Inferno may somehow mirror a disability scale. Methods: A detailed analysis of the text was carried out, which proved a valuable tool for interpreting the organization of punishments as a possible disability scale. The semantics of pain in the Divine Comedy was studied through all the forms of the pain descriptors (included the archaic terminological forms) from the Italian version of the McGill Pain Questionnaire (MGPQ) by Maiani and Sanavio. Results and Conclusions: In Dante's Inferno a classification of pain is provided, based on the experience of sufferings; Dante's images seem not only instrumental to investigating the sensorial but also the affective and intellectual spheres by introducing a number of characters and describing the impact of punishment onto their souls. Our research highlighted that 46 out of 78 terms from the MGPQ are present in Inferno, though with different forms; the Groups the MGPQ is divided into are also represented with the exception of Group XII, the most frequently detected being Groups XIII-which studies the fear-related sensations in the emotional sphere - XIV, XIX and XX. The great attention emerges that Dante devoted to describing simple sensorial experiences as well as the way punishments affected the soul. As a whole, the terms pertaining to the sensorial sphere are the most frequently encountered. The lack of motion which increases circle after circle in Hell, well matches the progressing physical and psychological impairment caused by some invalidating diseases. Noticeably, Dante created such a complex system centuries before the studies were released on the impact of pain and its quantitative and mostly qualitative definition. In conclusion, this interpretation suggests that the writing on the door to Hell which leads Dante into the inaccessible world of "the miserable race, those who have lost the good of intellect", may well be the title of a precise and incredibly up to date classification of painful sensations which are wonderfully described with simple and suggestive examples each time transforming into powerful images. …"Through me road to the city of desolation, / Through me the road to sorrows diuturnal, / Through me the road among the lost creation"

    Bitcoin as Safe Haven during Covid-19 Disease

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    In this paper, we investigate the role of Bitcoin as a safe haven against the stock market losses during the spread of COVID-19. The performed analysis was based on a regression model with dummy variables defined around some crucial dates of the pandemic and on the dynamic conditional correlations. To try to model the real dynamics of the markets, we studied the safe-haven properties of Bitcoin against thirteen of the major stock market indexes losses using daily data spanning from 1 July 2019 until 20 February 2021. A similar analysis was also performed for Ether. Results show that this pandemic impacts on the Bitcoin status as safe haven, but we are still far from being able to define Bitcoin as a safe haven

    A System Proposal for Information Management in Building Sector Based on BIM, SSI, IoT and Blockchain

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    This work presents a Self Sovereign Identity based system proposal to show how Blockchain, Building Information Modeling, Internet of Thing devices, and Self Sovereign Identity concepts can support the process of building digitalization, guaranteeing the compliance standards and technical regulations. The proposal ensures eligibility, transparency and traceability of all information produced by stakeholders, or generated by IoT devices appropriately placed, during the entire life cycle of a building artifact. By exploiting the concepts of the Self Sovereign Identity, our proposal allows the identification of all involved stakeholders, the storage off-chain of all information, and that on-chain of the sole data necessary for the information notarization and certification, adopting multi-signature approval mechanisms where appropriate. In addition it allows the eligibility verification of the certificated information, providing also useful information for facility management. It is proposed as an innovative system and companies that adopt the Open Innovation paradigm might want to pursue it. The model proposal is designed exploiting the Veramo platform, hence the Ethereum Blockchain, and all the recommendations about Self Sovereign Identity systems given by the European Blockchain Partnership, and by the World Wide Web Consortium

    Blockchain and self sovereign identity to support quality in the food supply chain

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    This work presents how a digital identity management system can support food supply chains in guaranteeing the quality of the products marketed and the compliance of the several supplychain’s nodes to standards and technical regulations. Specific goal of this work is to present a system that provides full visibility of process/food certifications, which nowadays are issued by accredited and approved certification bodies (issuers) and delivered and stored in paper version by the several participants (holders) of the supply chain. The system is designed and implemented by combining the latest most innovative and disruptive technologies in the market—Self Sovereign Identity system, Blockchain, and Inter Planetary File System. The crucial aspects that it aims to hit are the storage and access of food/process certifications, and the proper eligibility verification of these certifications exploiting the concepts of the Self Sovereign Identity-based models. The proposed system, realized by using standards that are WWW Consortium-compatible and the Ethereum Blockchain, ensures eligibility, transparency, and traceability of the certifications along a food supply chain, and could be an innovation model/idea that the companies that adopt the Open Innovation paradigm might want to pursue
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