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Analisi delle condizioni di sicurezza di una cava in esercizio con modelli del discontinuo. Memorie Gruppo Naz. Ing. Geotec
No full textAnalisi delle condizioni di sicurezza di una cava in esercizio con modelli del discontinuo
No full textEmpirical and numerical analysis of the blast - induced structural damage in rock tunnels
No full textOne of the main hazards in rock tunneling by using the drill and blast method is the damage of the nearby pre-existing underground structures due to ground vibrations generated by the explosion. A simplified empirical approach is commonly adopted for the assessment of blast - induced structural damage, based on the peak particle velocity (PPV) and related empirical threshold values. A more sophisticated approach consists in numerical analysis of rock – sup-port interaction under the dynamic load induced by blasting. This allows evaluate ground vibrations and internal forces inside the underground structures. Both approaches are applied in the present paper for evaluating the feasibility of a drill and blast tunnel excavation in the vicinity of a pre-existing tunnel. Based on the presented results, it is possible to conclude that the simplified empirical approach significantly overestimates the risk of the blast - induced structural damage compare to the numerical stress analyses
Stability analysis of an active marble quarry by DEM modelling
No full textThe marble quarry herein considered is located in the Apuan Alps (Italy), at the base of a deep gully cut by vertical walls, reaching a height of 180 m. The rock mass is cut across by different discontinuity sets, whose spacing is generally wide. The various sets significantly differ in persistency and thus affect the overall strength. In this paper the stability of a plane section of a typical steep face is studied by the Distinct Element Method. The stress-strain behaviour of the discontinuities is represented by the Barton-Bandis model and the presence of rock bridges is explicitly accounted for. The influence of different lengths of rock bridges and spacings on the overall stability was investigated by means of sensitivity analyses. Three different indexes were adopted to synthetically represent the severity of the stress state in the successive stages of excavation. Comparison among such parameters highlights similar trends as the excavation advances, thus indicating that the three indexes generally provide a “measure” of stability. The quarry faces exhibit a very limited amount of displacement and stability is obtained in each of the excavation steps
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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