1,721,020 research outputs found
Le nuove frontiere del contrasto alla criminalità: dalle investigazioni tecnologiche alla Predictive Policing al servizio della Urban Security
No full textIn questi ultimi anni è innegabile la crescita di una percezione generale di insicurezza nei contesti urbani. Il lavoro, muovendo da tali percezioni, ripercorre alcune esperienze italiane e straniere in materia di "predictive policing", vagliandone opportunità, affidabilità e utilità nella prevenzione e nella lotta alla criminalità e nell'ottica delle garanzie richieste dal sistema di giustizia penal
Validation of a strain gauge rosette setup on a cantilever specimen: Application to a calibration bench for residual stresses
Full text linkIt is commonly known that the most difficult part of measuring residual stresses through diffraction or relaxation methods is the high sensitivity of the results to input errors, such as noise in the strain data. Then, quantifying and minimizing stress uncertainties is at least as important as the residual stress results themselves. Results are often validated by leveraging different measurement techniques, although each method is somehow specialized at detecting residual stresses at different locations and length scales. This leads to a fundamental lack of ground truth data and an inherent difficulty in detecting biases.
The authors have introduced a calibration bench that facilitates the application of a well-known bending stress distribution on a specimen while conducting residual stress measurements using either the Hole-Drilling Method (HDM) or X-ray Diffraction (XRD). By leveraging Bueckner's superposition principle, the bench allows for determination of both the residual stress distribution and the reference stress distribution through a single experimental setup. This approach not only enables direct evaluation of accuracy but also identification of any procedural systematic errors, as the reference stress distribution is known with a high degree of certainty.
In this work, a detailed characterization of the stress and strain fields generated by the externally applied load was pursued. Then, the calibration bench was used to perform a validated characterization of residual stresses produced by two shot peening treatments, through both XRD and HDM. Additionally, both techniques were employed to verify the recognized bending stresses, thereby validating the findings of the residual stress measurements
Per un « benessere urbano »: prospettive di tutela penale e non solo. L’esempio paradigmatico del contrasto al (cyber) bullismo
No full textIl contributo analizza i profili criminologici e penali del bullismo e del cyberbullism
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
Dynamic behavior of a power re-circulating gear test rig including periodic variation of mesh stiffness and static transmission error
Full text linkWe characterized the dynamic behavior of a pair of high performance aeronautical gears which are part of a complex transmission system. The gear pair was tested using a mechanical recirculating power test rig designed to simulate the severe operating conditions of transmitted torque and angular speed. The test rig and the most important phenomena that influence its dynamic behavior are described. A (static) finite element model, developed to calculate the input parameters for the dynamic analysis of the tested gears, is also presented. Using the results of the FE model, we developed a lumped dynamical model with which it is possible to reproduce the most significant dynamic phenomena of the test rig. We characterized the behavior of the test rig focusing on the actual loads transmitted by the tested gears. The dynamic model was validated by comparing its results with the experimental outcomes in various test conditions. The comparison highlights the limitations of the design procedures based on common standards for assessing the dynamic overload experienced by heavy-duty gear transmission systems
Improved model for the prediction of the residual stress field in autofrettaged cylinders
No full textThe stress-strain curve in a loading-unloading process of high-strength steels can be significantly affected by the previous stress-strain history. In particular, if the material has accumulated plastic strain, the elastic modulus can decrease and the Bauschinger effect can impact the plastic response.
The combined effect of the reduction of the elastic modulus and the Bauschinger effect can affect the residual stress field in autofrettaged cylindrical pressure vessels. In particular, the value of the compressive residual stress at the bore is, at the same time, the one most impacted by the loss of either strength or stiffness and the one that bottle-necks the pressure vessel performances.
An experimental campaign has been performed to accurately measure the constitutive behavior for the high-strength steel of an autofrettaged component. Uniaxial tests were performed on specimens extracted from the above mentioned autofrettaged component. A complete 3-D incremental elastic-plastic constitutive model has been tuned to reproduce the observed behavior. This model, implemented in the ANSYS® commercial Code via User Programmable Features, has then been used to simulate the autofrettage process.
The residual stress field, obtained via the proposed FE simulation, was compared with the distribution measured on the component by means of the slitting method. The comparison was used to assess the validity of the proposed constitutive model and its numerical implementatio
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
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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