1,721,193 research outputs found
Ital'jancy v stalinskich lagerjach, Moskva, Rosspen, 2009 (titolo originale dell'opera "Italiani nei lager di Stalin", Roma-Bari, Laterza, 2006)
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Destructive interference from three partially coherent point sources
No full textA simple experiment performed with a three-pinhole interferometer is presented. It is shown that, as predicted by
Gbur, Visser, and Wolf [Opt. Commun. 239 (2004) 15], complete destructive interference can take place even if the fields
emerging from the pinholes are not fully coherent with respect to each other. An intuitive interpretation of this effect is
suggested
Phase and Amplitude Retrieval in Ghost Diffraction from Field-Correlation Measurements
No full textWe report the results of experiments about the inversion of ghost diffraction with pseudothermal light. A complete retrieval of the complex transmission function of planar transparencies, illuminated by spatially incoherent, quasimonochromatic light, is achieved. This is obtained by measuring the field (instead of the intensity) correlation function. In particular, the determination of the phase of the correlation function is made particularly easy and robust by the use of a suitably modified Young interferometer. The presented results r
Maximizing Young’s fringe visibility through reversible optical transformations
No full textWhen a Young's interferometer is fed by an electromagnetic beam, fringes of low, or even zero, visibility do not necessarily indicate lack of correlation between two typical field components at the pinholes. The passage of light that emerges from one of the pinholes through a nonabsorbing anisotropic optical element may enhance the visibility. We inquire about the maximum visibility that can be attained through such a reversible transformation (polarizers being excluded). We find that such a quantity can be evaluated in closed form. Its value is directly related to the Ky Fan 1-norm of the correlation matrix of the illuminating beam
Evaluation of Stereo Algorithms for 3D Object Recognition
No full textThis work aims at evaluating stereo matching algorithms
in a 3D object recognition scenario, wherein objects have
to be found and their 3D pose estimated efficiently and in
presence of clutter and occlusions. Unlike all other surveys
and evaluations of stereo methods, which compare accuracy
based on a dataset of disparity maps with ground-truth, this
work proposes an evaluation in terms of recognition ability
which leverages on state-of-the-art approaches for 3D
object recognition. The proposed evaluation methodology
comprises a novel dataset characterized by realistic working
conditions and compares state-of-the-art stereo algorithms
potentially suitable to 3D object recognition applications
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