712 research outputs found

    The Tale of the Roman Theater of Philadelphia, Amman. Representative and experiential methodology of the theatrical space

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    The project aims to present the 3D reconstruction of the Roman Theater of Amman, the ancient Philadelphia of the Palestinian Decapolis, through rigorous representative models. The outcomes will be part of a future exhibition providing site-specific installations and user experience artifacts based on digital interaction and tactile models. The paper illustrates the multidisciplinary approach associated with using 3D virtual reconstruction and game engine tools to reflect on the practice of representing ancient monuments and digital museology. Travelers of the 18th and 19th centuries drafted the fascination of discovery as an experience in their notebooks. At the same time, their written records could address contemporary visitors to an extensive cultural knowledge of places and buildings, the historia of Philadelphia. Investigations are shifting scientific models towards a dynamic cultural experience representative of cultural heritage, including intangible heritage, stories, and new technological paradigms, increasingly rapidly making it possible to duplicate art and heritage. This shift is pinpointing the role of representation for cultural studies and humanities, experimenting with practices and tools to drill methodologies, and producing models for interaction design, socialization, gaming, and museum experience

    Dynamical instability of a spin spiral in an interacting Fermi gas as a probe of the Stoner transition

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    We propose an experiment to probe ferromagnetic phenomena in an ultracold Fermi gas, while alleviating the sensitivity to three-body loss and competing many-body instabilities. The system is initialized in a small pitch spin spiral, which becomes unstable in the presence of repulsive interactions. To linear order the exponentially growing collective modes exhibit critical slowing down close to the Stoner transition point. Also, to this order, the dynamics are identical on the paramagnetic and ferromagnetic sides of the transition. However, we show that scattering off the exponentially growing modes qualitatively alters the collective mode structure. The critical slowing down is eliminated and in its place a new unstable branch develops at large wave vectors. Furthermore, long-wavelength instabilities are quenched on the paramagnetic side of the transition. We study the experimental observation of the instabilities, specifically addressing the trapping geometry and how phase-contrast imaging will reveal the emerging domain structure. These probes of the dynamical phenomena could allow experiments to detect the transition point and distinguish between the paramagnetic and ferromagnetic regimes

    SOM-Based Approach for the Analysis and Classification of Synchronous Impulsive Noise of an In-Ship PLC System

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    The interest in wideband data transmission over power line communications has increased rapidly. This technology offers a convenient and inexpensive medium to transmit data, reducing the number of cables. This advantage is particularly appealing in many fields, like the railway, naval, and aeronautical ones. Nevertheless, several problems have to be faced to obtain a high data rate. In particular, the presence of noise makes the transmission difficult, degrading the quality of received signals and prohibiting the full application of these communication frameworks. In this paper the behaviour of an in-ship powerline communication system is analyzed in the presence of synchronous periodic impulsive noise. Such noise is modelled at source and its effects on the transmission of wideband signals are evaluated by means of a simulation circuit model. The obtained results allow to identify the characteristics of the channel and the critical conditions due to noise. Subsequently, an unsupervised technique based on principal component analysis and fuzzy c-mean classifier detects the presence and classifies the specific noises. Numerical results show that the proposed approach enables to achieve this target accurately under different operating conditions, proving to be an effective tool to enhance the performances of the considered technology

    Energy balance of a laser ablation plume expanding in a background gas

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    The energy balance of a laser ablation plume in an ambient gas for nanosecond pulses has been investigated on the basis of the model of Predtechensky and Mayorov (PM), which provides a relatively simple and clear description of the essential hydrodynamics. This approach also leads to an insightful description in dimensionless units of how the initial kinetic energy of the plume is dissipated into kinetic and thermal energy of the background gas. Eventually when the plume has stopped, the initial kinetic energy of the plume is converted into thermal energy of the plume and background gas

    Reshaping the Museum of Zoology in Rome by Visual Storytelling and Interactive Iconography

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    This article summarizes the concept of a new immersive and interactive setting for the Zoology Museum in Rome, Italy. The concept, co-designed with all the museum’s curators, is aimed at enhancing the experiential involvement of the visitors by visual storytelling and interactive iconography. Thanks to immersive and interactive technologies designed by Centro Studi Logos, developed by Logosnet and known as e-REALâ and MirrorMeä, zoological findings and memoirs come to life and interact directly with the visitors in order to deepen their understanding, visualize stories and live experiences, and interact with the founder of the Museum (Mr. Arrigoni degli Oddi) who is now a virtualized avatar, or digital human, able to talk with the visitors. All the interactions are powered through simple hand gestures and, in a few cases, vocal inputs that transform into recognized commands from multimedia systems

    Zero sound in a single component fermion - Bose Einstein Condensate mixture

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    The resonant dynamics of mediated interactions supports zero-sound in a cold atom degenerate mixture of a single component fermion gas and a Bose-Einstein condensate (BEC). We characterize the onset of instability in the phase separation of an unstable mixture and we find a rich collective mode structure for stable mixtures with one undamped mode that exhibits an avoided crossing and a Landau-damped mode that terminates.Comment: 4 pages, 2 figure

    Subextensive singularity in the 2D ±J\pm J Ising spin glass

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    The statistics of low energy states of the 2D Ising spin glass with +1 and -1 bonds are studied for L×LL \times L square lattices with L≤48L \le 48, and pp = 0.5, where pp is the fraction of negative bonds, using periodic and/or antiperiodic boundary conditions. The behavior of the density of states near the ground state energy is analyzed as a function of LL, in order to obtain the low temperature behavior of the model. For large finite LL there is a range of TT in which the heat capacity is proportional to T5.33±0.12T^{5.33 \pm 0.12}. The range of TT in which this behavior occurs scales slowly to T=0T = 0 as LL increases. Similar results are found for pp = 0.25. Our results indicate that this model probably obeys the ordinary hyperscaling relation dν=2−αd \nu = 2 - \alpha, even though Tc=0T_c = 0. The existence of the subextensive behavior is attributed to long-range correlations between zero-energy domain walls, and evidence of such correlations is presented.Comment: 13 pages, 7 figures; final version, to appear in J. Stat. Phy

    Phonon spectrum and dynamical stability of a quantum degenerate Bose-Fermi mixture

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    We calculate the phonon excitation spectrum in a zero-temperature boson-fermion mixture. We show how the sound velocity changes due to the boson-fermion interaction and we determine the dynamical stability regime of a homogeneous mixture. We identify a resonant phonon-exchange interaction between the fermions as the physical mechanism leading to the instability.Comment: 4 pages, 3 figure

    Computing the Loewner driving process of random curves in the half plane

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    We simulate several models of random curves in the half plane and numerically compute their stochastic driving process (as given by the Loewner equation). Our models include models whose scaling limit is the Schramm-Loewner evolution (SLE) and models for which it is not. We study several tests of whether the driving process is Brownian motion. We find that just testing the normality of the process at a fixed time is not effective at determining if the process is Brownian motion. Tests that involve the independence of the increments of Brownian motion are much more effective. We also study the zipper algorithm for numerically computing the driving function of a simple curve. We give an implementation of this algorithm which runs in a time O(N^1.35) rather than the usual O(N^2), where N is the number of points on the curve.Comment: 20 pages, 4 figures. Changes to second version: added new paragraph to conclusion section; improved figures cosmeticall

    Collisionless collective modes of fermions in magnetic traps

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    We present a Random-Phase-Approximation formalism for the collective spectrum of two hyperfine species of dilute 40K atoms, magnetically trapped at zero temperature and subjected to a repulsive s-wave interaction between atoms with different spin projections. We examine the density-like and the spin-like oscillation spectra, as well as the transition density profiles created by external multipolar fields. The zero sound spectrum is always fragmented and the density and spin channels become clearly distinguishable if the trapping potentials acting on the species are identical. Although this distinction is lost when these confining fields are different, at selected excitation frequencies the transition densities may display the signature of the channel.Comment: 10 pages, 9 figure
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