286 research outputs found

    Integrating Foundational Data Management Course into STEM

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    This presentation was delivered at the IOLUG conference-Tackling Data in Libraries: Opportunities and Challenges in Serving User Communities in Indianapolis, IN in May 2019. Data literacy is critical for today’s college graduates. Data science education is fundamentally an interdisciplinary endeavor. Since summer 2018, the presenters, information professionals from the libraries, have been working with instructors from Philosophy and Computer and Electrical Engineering to develop three interlocking one-credit courses at the Midwest, public research university, Purdue University. Spring 2019, the courses are offered to engineering sophomore and junior students to explore three key areas of data literacy: management; ethics; and analysis. In this session, participants learned how we developed the libraries’ one-credit course on data management and we discussed how this course could be interlocked with two other courses. Welcome to contact and work with the presenters for class implementation and research collaboration

    Search for Lambda^2/p^2 corrections to the QCD running coupling

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    We investigate the occurrence of power terms (Lambda2/p2(Lambda^2/p^2 in the running QCD coupling by analysing non-perturbative measurements of αs(p)\alpha_s(p) at quite low momenta obtained from the lattice three-gluon vertex. Our study provides some evidence for such a contribution. The phenomenological implications of such a presence are reviewed.Comment: 3 pages, 1 figure, LaTeX, LATTICE98(Confinement

    Monopole clusters at short and large distances

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    We present measurements of various geometrical characteristics of monopole clusters in SU(2) lattice gauge theory. The maximal Abelian projection is employed and both infinite, or percolating cluster and finite clusters are considered. In particular, we observe scaling for average length of segments of the percolating cluster between self-crossings, correlators of vacuum monopole currents, angular correlation between links along trajectories. Short clusters are random walks and their spectrum in length corresponds to free particles. At the hadronic scale, on the other hand, the monopole trajectories are no longer random walks. Moreover, we argue that the data on the density of finite clusters suggest that there are long-range correlations between finite clusters which can be understood as association of the clusters with two-dimensional surfaces, whose area scales.Comment: 9 pages, 11 figure

    Valley Bifurcation in an O(3)O(3) σ\sigma Model: Implications for High-Energy Baryon Number Violation

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    The valley method for computing the total high-energy anomalous cross section SanomS_{anom} is the extension of the optical theorem to the case of instanton-antiinstanton backgrounds. As a toy model for baryon number violation in Electroweak theory, we consider a version of the O(3)O(3) σ\sigma model in which the conformal invariance is broken perturbatively. We show that at a critical energy the saddle-point values of the instanton size and instanton-antiinstanton separation bifurcate into complex conjugate pairs. This nonanalytic behavior signals the breakdown of the valley method at an energy where SanomS_{anom} is still exponentially suppressed. (Figures replaced 5/3/93).Comment: (14 pages, Los Alamos Preprint LA-UR-93-811). 3 uuencoded figures include

    Stopping Light on a Defect

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    Gap solitons are localized nonlinear coherent states which have been shown both theoretically and experimentally to propagate in periodic structures. Although theory allows for their propagation at any speed vv, 0vc0\le v\le c, they have been observed in experiments at speeds of approximately 50% of cc. It is of scientific and technological interest to trap gap solitons. We first introduce an explicit multiparameter family of periodic structures with localized defects, which support linear defect modes. These linear defect modes are shown to persist into the nonlinear regime, as {\it nonlinear defect modes}. Using mathematical analysis and numerical simulations we then investigate the capture of an incident gap soliton by these defects. The mechanism of capture of a gap soliton is resonant transfer of its energy to nonlinear defect modes. We introduce a useful bifurcation diagram from which information on the parameter regimes of gap soliton capture, reflection and transmission can be obtained by simple conservation of energy and resonant energy transfer principles.Comment: 45 pages, Submitted to Journal of the Optical Society

    HAAR: Text-Conditioned Generative Model of 3D Strand-based Human Hairstyles

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    We present HAAR, a new strand-based generative model for 3D human hairstyles. Specifically, based on textual inputs, HAAR produces 3D hairstyles that could be used as production-level assets in modern computer graphics engines. Current AI-based generative models take advantage of powerful 2D priors to reconstruct 3D content in the form of point clouds, meshes, or volumetric functions. However, by using the 2D priors, they are intrinsically limited to only recovering the visual parts. Highly occluded hair structures can not be reconstructed with those methods, and they only model the ''outer shell'', which is not ready to be used in physics-based rendering or simulation pipelines. In contrast, we propose a first text-guided generative method that uses 3D hair strands as an underlying representation. Leveraging 2D visual question-answering (VQA) systems, we automatically annotate synthetic hair models that are generated from a small set of artist-created hairstyles. This allows us to train a latent diffusion model that operates in a common hairstyle UV space. In qualitative and quantitative studies, we demonstrate the capabilities of the proposed model and compare it to existing hairstyle generation approaches.Comment: For more results please refer to the project page https://haar.is.tue.mpg.de

    Homogeneous AlGaN/GaN superlattices grown on free-standing (1(1)over-bar00) GaN substrates by plasma-assisted molecular beam epitaxy

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    Two-dimensional and homogeneous growth of m-plane AlGaN by plasma-assisted molecular beam epitaxy has been realized on free-standing (1 (1) over bar 00) GaN substrates by implementing high metal-to-nitrogen (III/N) flux ratio. AlN island nucleation, often reported for m-plane AlGaN under nitrogen-rich growth conditions, is suppressed at high III/N flux ratio, highlighting the important role of growth kinetics for adatom incorporation. The homogeneity and microstructure of m-plane AlGaN/GaN superlattices are assessed via a combination of scanning transmission electron microscopy and high resolution transmission electron microscopy (TEM). The predominant defects identified in dark field TEM characterization are short basal plane stacking faults (SFs) bounded by either Frank-Shockley or Frank partial dislocations. In particular, the linear density of SFs is approximately 5 x 10(-5) cm(-1), and the length of SFs is less than 15 nm. (C) 2013 AIP Publishing LLC

    Flux-Tube Formation and Holographic Tunneling

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    We consider correlator of two concentric Wilson loops, a small and large ones related to the problem of flux-tube formation. There are three mechanisms which can contribute to the connected correlator and yield different dependences on the radius of the small loop. The first one is quite standard and concerns exchange by supergravity modes. We also consider a novel mechanism when the flux-tube formation is described by a barrier transition in the string language, dual to the field-theoretic formulation of Yang-Mills theories. The most interesting possibility within this approach is resonant tunneling which would enhance the correlator of the Wilson loops for particular geometries. The third possibility involves exchange by a dyonic string supplied with the string junction. We introduce also t'Hooft and composite dyonic loops as probes of the flux tube. Implications for lattice measurements are briefly discussed.Comment: 15 pages, 3 figure

    A novel probe of the vacuum of the lattice gluodynamics

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    We introduce a notion of minimal number of negative links on the lattice for a given original configuration of SU(2) fields. Negative links correspond to a large potential, not necessarily large action. The idea is that the minimal number of negative links is a gauge invariant notion. To check this hypothesis we measure correlator of two negative links, averaged over all the directions, as function of the distance between the links. The inverse correlation length coincides within the error bars with the lightest glueball mass.Comment: 6 pages, 2 figure
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