1,721,006 research outputs found
Metrological characterization of a low-cost portable stereo vision system for dynamic measurements
No full textIn recent years, camera and computer systems have been miniaturized considerably. The market now offers several low-cost products to assemble a small scale portable stereo vision system which can be completely autonomous (since it can acquire and process image). However, the metrological characteristics of such a portable stereo vision device should be assessed and compared with the state of the art of stereo vision system. In this work a portable stereo vision system composed by small board cameras and a single board computer is metrologically characterized and validated with respect to fixed non-portable systems. The analysis focused on the application of such a stereo rig to DIC and stereoscopic measurements performed with commercial software. For these tests two algorithms with different correlation techniques are evaluated in Matlab and in Halcon, moreover, a 3D DIC analysis is conducted on a H-shape specimen. To perform a metrological characterization, the points clouds obtained from the triangulations are confined to a region of the scene containing only a part of the specimen, after that they are fitted with a LOWESS fitting model. The uncertainty is assessed by computing the discrepancy between the points of the cloud and the ones of the fitting model. In some algorithms more than others the errors distribute in a strongly periodic manner with a period linked to integer values of disparity. Eventually the experimental analysis demonstrated that the accuracy of such a lightweight stereo system is similar to the accuracy of traditional not-portable ones
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Impianto di condrociti autologhi su membrana collagenica (MACI): analisi a medio termine dei risultati clinici e di imaging
No full textBirth after direct intraperitoneal insemination with frozen semen of donor.
No full textFor the first time, as least as far we known, a pregnancy and a normal baby obtained with DII with frozen semen of donor are reported. Our experience not only shows DII with frozen semen may be used successfully in AID but that it poses interesting hypotheses, to be verified in future, of its use in association with, or as an alternative to, GIFT and IVF/ET in cases of AID failure and as a first approach to an insemination technique in AID in general
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