1,722,218 research outputs found
La crisis de representación política. El caso argentino
No full textFil: Oltra Santa Cruz, Fernando. Universidad Católica de Santa Fe ; Argentin
Fabrication of structured GLS-Se glass preforms for fibre drawing
No full textGallium lanthanum sulfide (GLS) with the addition of selenium (Se) glasses, have been proven as a reliable medium to transmit light in the range from the visible to the longwave infrared (LWIR). This family of chalcogenide glasses offer a broad transparency window depending on the composition. Their optical, mechanical and thermal properties have been exploited in their bulk form. Increasing interest in chalcogenide photonics research includes sensing for the civil, medical and military areas, as the molecular fingerprint region is within the GLS-Se glass transmission window. These application areas exploit the GLS-Se characteristics in an optical fibre geometry. The aim of this work was to explore the feasibility of obtaining glass rods and structured preforms from GLS-Se glass that could be drawn into optical fibres. For this, the extrusion process is explored by emphasizing the need to maintain the desirable glass characteristics throughout the entire process, from the glass melting to the fibre drawing. For this purpose, each step was studied and defined to maximise the exploitation of the equipment and the materials involved. For the first time it is shown that GLS-Se glasses can be extruded with a minimum alteration of their optical, thermal and mechanical properties. The amorphous phase was maintained, and corroborated by refractive index measurements, Raman spectroscopy and XRD. Several challenges were arisen during this work, using each of them to fully complete and develop a methodology to be able to obtain optical fibres. Further work might include reducing the losses of the optical fibres using this process
Enabling secure passwords via Deep Learning: Towards a new generation of attacks and defenses
Full text linkIn the present thesis, we aim at alleviating the inherent limitations affecting current solu- tions in password security. First and foremost, this process requires to devise adversary models that accurately describe real-world guessing attacks. Then, it necessitates the im- plementation of techniques that are capable of guiding users to choose secure and usable passwords at composition time.
Unfortunately, despite more than three decades of active research dedicated to define and improve these methodologies, existing approaches still present two major drawbacks: (1) current adversary models rely on simplistic adversarial behaviors that only imperfectly describe the guessing strategies adopted by real-world attackers; (2) existing proactive techniques such as password strength meters, by construction, are unable to fully support users during the password composition process.
Here, we show how Deep Learning techniques allow us to define novel approaches, that were either unfeasible or unpractical before and that move towards addressing those issues:
(1) We introduce dynamic adversary models in password guessing. Similarly to real-world adversaries, dynamic models automatically adjust their guessing strategy for the current attacked-set of passwords by exploiting information collected during the running attack.
(2) We introduce new guessing techniques that make dictionary attacks consis- tently more resilient to inadequate configurations. This novel framework allows dictionary attacks to self-heal and move towards optimal attacks’ performance, requiring no supervision.
(3) We introduce Interpretable Probabilistic Password Strength Meters. This novel class of meters exhibits a natural and general feedback mechanism capable of de- scribing to the users the latent relation between password strength and password struc- ture. Unlike existing heuristic constructions, this method is free from any human bias, and, more importantly, its feedback has a clear probabilistic interpretation.
Eventually, these general techniques allow us to increase the rigorousness and reliabil- ity of password security analysis and proactive methodologies that stem on top of them
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
L'Alhambra. Traduite par Jules Boutellier...
No full textDonado a la biblioteca universitaria de Granada por D. Fernando Gómez de la Cruz, en memoria de la poetisa granadina Dª. Enriqueta Lozan
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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