1,964 research outputs found

    An interactive, generative Punch and Judy show using institutions, ASP and emotional agents

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    Using Punch and Judy as a story domain, we describe an interactive puppet show, where the flow and content of the story can be influenced by the actions of the audience. As the puppet show is acted out, the audience reacts to events by cheering or booing the characters. This affects the agents’ emotional state, potentially causing them to change their actions, altering the course of the narrative. An institutional normative model is used to constrain the narrative so that it remains consistent with the Punch and Judy canon. Through this vignette of a socio-technical system (STS), comprising human and software actors, an institutional model – derived from narrative theory – and (simplistic) technological interaction artifacts, we begin to be able to explore some of the issues that can arise in STS through the prism of the World-Institution-Technology (WIT) model

    Epitaxial Growth of La1/3_{1/3}Sr2/3_{2/3}FeO3_3 thin films by laser ablation

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    We report on the synthesis of high quality La1/3_{1/3}Sr2/3_{2/3}FeO3_3 (LSFO) thin films using the pulsed laser deposition technique on both SrTiO3_3 (STO) and LaAlO3_3 (LAO) substrates (100)-oriented. From X-Ray diffraction (XRD) studies, we find that the films have an out-of-plane lattice parameter around 0.3865nm, almost independent of the substrate (i.e. the nature of the strains). The transport properties reveal that, while LSFO films deposited on STO exhibit an anomaly in the resistivity vs temperature at 180K (corresponding to the charge-ordered transition and associated with a transition from a paramagnetic to an antiferromagnetic state), the films grown on LAO display a very small magnetoresistance behavior and present an hysteresis around 270K under the application of a 4T magnetic field. The changes in transport properties between both substrates are discussed and compared with the corresponding single crystals.Comment: 9 pages, 4 figure

    Irreducible Hamiltonian approach to the Freedman-Townsend model

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    The irreducible BRST symmetry for the Freedman-Townsend model is derived. The comparison with the standard reducible approach is also addressed.Comment: 18 pages, LaTeX 2.0

    Sparsity driven ultrasound imaging

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    An image formation framework for ultrasound imaging from synthetic transducer arrays based on sparsity-driven regularization functionals using single-frequency Fourier domain data is proposed. The framework involves the use of a physics-based forward model of the ultrasound observation process, the formulation of image formation as the solution of an associated optimization problem, and the solution of that problem through efficient numerical algorithms. The sparsity-driven, model-based approach estimates a complex-valued reflectivity field and preserves physical features in the scene while suppressing spurious artifacts. It also provides robust reconstructions in the case of sparse and reduced observation apertures. The effectiveness of the proposed imaging strategy is demonstrated using experimental data

    Multi-Resolution Analysis and Fractional Quantum Hall Effect: an Equivalence Result

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    In this paper we prove that any multi-resolution analysis of \Lc^2(\R) produces, for some values of the filling factor, a single-electron wave function of the lowest Landau level (LLL) which, together with its (magnetic) translated, gives rise to an orthonormal set in the LLL. We also give the inverse construction. Moreover, we extend this procedure to the higher Landau levels and we discuss the analogies and the differences between this procedure and the one previously proposed by J.-P. Antoine and the author.Comment: Submitted to Journal Mathematical Physisc

    Atmospheric Variability Of Methyl Chloride During the Last 300 Years From an Antarctic Ice Core and Firn Air

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    Measurements of methyl chloride (CH3Cl) in Antarctic polar ice and firn air are used to describe the variability of atmospheric CH3Cl during the past 300 years. Firn air results from South Pole and Siple Dome suggest that the atmospheric abundance of CH3Cl increased by about 10% in the 50 years prior to 1990. Ice core measurements from Siple Dome provide evidence for a cyclic natural variability on the order of 10%, with a period of about 110 years in phase with the 20th century rise inferred from firn air. Thus, the CH3Cl increase measured in firn air may largely be a result of natural processes, which may continue to affect the atmospheric CH3Cl burden during the 21st century

    Temperature-dependent soft x-ray photoemission and absorption studies of charge disproportionation in La1x_{1-x}Srx_xFeO3_3

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    We have measured the temperature dependence of the photoemission and x-ray absorption spectra of La1x_{1-x}Srx_xFeO3_3 (LSFO) epitaxial thin films with x=0.67x=0.67, where charge disproportionation (3Fe3.67+2Fe3++Fe5+3{Fe}^{3.67+}\to 2{Fe}^{3+}+ {Fe}^{5+}) resulting in long-range spin and charge ordering is known to occur below TCD=190T_{CD}=190 K. With decreasing temperature we observed gradual changes of the spectra with spectral weight transfer over a wide energy range of 5\sim 5 eV. Above TCDT_{CD} the intensity at the Fermi level (EFE_F) was relatively high compared to that below TCDT_{CD} but still much lower than that in conventional metals. We also found a similar temperature dependence for x=0.4x=0.4, and to a lesser extent for x=0.2x=0.2. These observations suggest that a local charge disproportionation occurs not only in the x=0.67x=0.67 sample below TCDT_{CD} but also over a wider temperature and composition range in LSFO. This implies that the tendency toward charge disproportionation may be the origin of the unusually wide insulating region of the LSFO phase diagram.Comment: 6 pages, 8 figure

    Chiral Perturbation Theory for τρπντ\tau \to \rho \pi\nu_\tau, τKπντ\tau \to K^* \pi \nu_\tau, and τωπντ\tau \to \omega \pi \nu_\tau

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    We use heavy vector meson SU(2)L×SU(2)RSU(2)_L \times SU(2)_R chiral perturbation theory to predict differential decay distributions for τρπντ\tau \rightarrow \rho \pi \nu_\tau and τKπντ\tau \rightarrow K^* \pi \nu_\tau in the kinematic region where pVpπ/mVp_V \cdot p_\pi/m_V (here V=ρV = \rho or KK^*) is much smaller than the chiral symmetry breaking scale. Using the large number of colors limit we also predict the rate for τωπντ\tau \rightarrow \omega \pi \nu_\tau in this region (now V=ωV = \omega). Comparing our prediction with experimental data, we determine one of the coupling constants in the heavy vector meson chiral Lagrangian.Comment: 14 pages, latex 2e. We include the decay of the tau into the omega, pi minus and the tau neutrino, and extract a value for the coupling constant g2, using experimental dat

    A provenance task abstraction framework

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    Visual analytics tools integrate provenance recording to externalize analytic processes or user insights. Provenance can be captured on varying levels of detail, and in turn activities can be characterized from different granularities. However, current approaches do not support inferring activities that can only be characterized across multiple levels of provenance. We propose a task abstraction framework that consists of a three stage approach, composed of (1) initializing a provenance task hierarchy, (2) parsing the provenance hierarchy by using an abstraction mapping mechanism, and (3) leveraging the task hierarchy in an analytical tool. Furthermore, we identify implications to accommodate iterative refinement, context, variability, and uncertainty during all stages of the framework. A use case describes exemplifies our abstraction framework, demonstrating how context can influence the provenance hierarchy to support analysis. The paper concludes with an agenda, raising and discussing challenges that need to be considered for successfully implementing such a framework
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