4,996 research outputs found

    Finding Person Relations in Image Data of the Internet Archive

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    The multimedia content in the World Wide Web is rapidly growing and contains valuable information for many applications in different domains. For this reason, the Internet Archive initiative has been gathering billions of time-versioned web pages since the mid-nineties. However, the huge amount of data is rarely labeled with appropriate metadata and automatic approaches are required to enable semantic search. Normally, the textual content of the Internet Archive is used to extract entities and their possible relations across domains such as politics and entertainment, whereas image and video content is usually neglected. In this paper, we introduce a system for person recognition in image content of web news stored in the Internet Archive. Thus, the system complements entity recognition in text and allows researchers and analysts to track media coverage and relations of persons more precisely. Based on a deep learning face recognition approach, we suggest a system that automatically detects persons of interest and gathers sample material, which is subsequently used to identify them in the image data of the Internet Archive. We evaluate the performance of the face recognition system on an appropriate standard benchmark dataset and demonstrate the feasibility of the approach with two use cases

    In the Interest of Everyone? Support for Social Movement Unionism among Union Officials in Quebec (Canada)

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    Using a mixed-method research design involving interviews and a survey, we examined how union officials in Quebec perceive social movement unionism (SMU). We show that union officials view SMU as a multifaceted phenomenon with ideal and pragmatic dimensions. They are torn between strong support for the ideals of SMU and a practical reluctance to use members’ dues to provide services to non-members. Experience with civil society organisations mitigates this tension, encouraging union officials to defend the interests of everyone not only as an ideal, but also as a strategy that allows unions to protect members and unrepresented workers.1. WITHIN AND BEYOND UNIONS: INTRODUCTION 2. ROOTS AND RAMIFICATIONS OF SMU: THEORETICAL FRAMEWORK 3. A MIXED-METHOD APPROACH APPLIED TO THE CASE OF QUEBEC TUs 4. SMU AS A MULTIDIMENSIONAL CONSTRUCT: AN EXPLORATIVE QUANTITATIVE ANALYSIS 5. IDEALLY INCLINED, PRAGMATICALLY RELUCTANT: DISCUSSION 6. IDEAL VERSUS PRAGMATIC TENSION IN SMU: DELVING DEEPER AND WIDER ACKNOWLEDGEMENTS Supporting Information REFERENCE

    On the Use of Wavelet Transform for Quench Precursors Characterisation in the LHC Superconducting Dipole Magnets

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    Premature training quenches are caused by transient energy released within the magnet coil while it is energized. Signals recorded across the so-called quench antenna carry information about these disturbances. A new method for identifying and characterizing those events is proposed, which applies the wavelet transform approach to the recorded signals. Such an approach takes into account the time of occurrence as well as frequency content of the events. The choice of the optimal mother wavelet is discussed, and the results obtained from the application of the method to actual signals are given. The criteria to recognize the interesting events are presented as well as the methodology to classify their global behavior

    Crossing Over from Attractive to Repulsive Interactions in a Tunneling Bosonic Josephson Junction

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    We explore the interplay between tunneling and interatomic interactions in the dynamics of a bosonic Josephson junction. We tune the scattering length of an atomic 39^{39}K Bose-Einstein condensate confined in a double-well trap to investigate regimes inaccessible to other superconducting or superfluid systems. In the limit of small-amplitude oscillations, we study the transition from Rabi to plasma oscillations by crossing over from attractive to repulsive interatomic interactions. We observe a critical slowing down in the oscillation frequency by increasing the strength of an attractive interaction up to the point of a quantum phase transition. With sufficiently large initial oscillation amplitude and repulsive interactions the system enters the macroscopic quantum self-trapping regime, where we observe coherent undamped oscillations with a self-sustained average imbalance of the relative well population. The exquisite agreement between theory and experiments enables the observation of a broad range of many body coherent dynamical regimes driven by tunable tunneling energy, interactions and external forces, with applications spanning from atomtronics to quantum metrology.Comment: 10 pages, 8 figures, supplemental materials are include

    Low-resolution spectroscopy of the Sunyaev-Zel'dovich effect and estimates of cluster parameters

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    The Sunyaev-Zel'dovich (SZ) effect is a powerful tool for studying clusters of galaxies and cosmology. Large mm-wave telescopes are now routinely detecting and mapping the SZ effect in a number of clusters, measure their comptonisation parameter and use them as probes of the large-scale structure and evolution of the universe. We show that estimates of the physical parameters of clusters (optical depth, plasma temperature, peculiar velocity, non-thermal components etc.) obtained from ground-based multi-band SZ photometry can be significantly biased, owing to the reduced frequency coverage, to the degeneracy between the parameters and to the presence of a number of independent components larger than the number of frequencies measured. We demonstrate that low-resolution spectroscopic measurements of the SZ effect that also cover frequencies >270> 270 GHz are effective in removing the degeneracy. We used accurate simulations of observations with lines-of-sight through clusters of galaxies with different experimental configurations (4-band photometers, 6-band photometer, multi-range differential spectrometer, full coverage spectrometers) and different intracluster plasma stratifications. We find that measurements carried out with ground-based few-band photometers are biased towards high electron temperatures and low optical depths, and require coverage of high frequency and/or independent complementary observations to produce unbiased information; a differential spectrometer that covers 4 bands with a resolution of $\sim 6 \ GHz$ eliminates most if not all bias; full-range differential spectrometers are the ultimate resource that allows a full recovery of all parameters.Comment: in pres
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