1,720,979 research outputs found
Assessment of the seismic risk associated with small earth dams: a simplified approach
Full text linkSmall earth dams are characterized by a reduced height of the retaining structure and by a limited reservoir volume of water. They are often located along slopes close to populated areas, therefore the risk associated with their potential rupture could be considerable. Also for this reason, the evaluation of their seismic vulnerability is of paramount importance for Civil Protection purposes. In addition, the usual lack of technical information represents a significant further challenge. In this regards, a simplified methodology based on a reduced number of parameters was required for vulnerability assessment studies. A simplified procedure was developed to systematically classify a large number of small earth dams. The proposed methodology is based on the compilation of data-sheets that lead to a preliminary classification of structures in terms of their associated seismic risk. The application of this procedure to about a hundred earth dams in the Piedmont region allowed
identifying the most critical structures, which require a priority in the planning of further investigations and analyses
A new geostatistical model for shear wave velocity profiles
No full textA consistent procedure is required to deal with uncertainties in seismic hazard studies. In particular, uncertainties in shear wave velocity (VS) profiles are important for 1D numerical simulations of site response conducted within a probabilistic framework. This work proposes a new geostatistical model for shear wave velocity profiles. The main characteristic of the model is the separation of the random variables space and time. The model is calibrated using a database of surface wave tests compiled for this purpose. The flexibility of the model is then demonstrated by presenting a first prototype version for down-hole tests. The proposed geostatistical model is validated through an application to a real case study at Mirandola (Italy), one of the sites included in the InterPACIFIC project. The results show a significant improvement in the management (i.e., treatment) of uncertainties for ground response analyses, compared to the methods usually adopted for this purpose. The new geostatistical model allows for a rigorous quantification of the uncertainties introduced in the hazard study; these uncertainties depend on both the characteristics of the investigated site and the performed test. It is also shown that the randomization procedure provides a set of profiles which are fully consistent with the independent experimental “site signatures” available at the site
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
Time-weighted average shear wave velocity profiles from surface wave tests through a wavelength-depth transformation
No full textWe investigate the possibility of obtaining time-weighted average shear wave velocity profiles through a wavelength-depth transformation of experimental dispersion curves from surface wave tests, without a formal solution of the inverse problem. We evaluate this approach on a wide flat-file database (Polito Surface Wave Database, PSWD) of experimental dispersion curves and related shear wave velocity profiles, both from dispersion curve inversion and invasive tests. The results show that the proposed wavelength-depth transformation can be valuable for seismic site evaluations offering an estimation of time-weighted average shear wave velocity profiles very similar to a state-of-the-art inversion of the experimental dispersion curves and with similar uncertainty with respect to invasive tests. This transformation has the advantage of avoiding time-consuming inversion processes, with related uncertainty sources, and any assumption on layer parameterization and a-priori information. Moreover, in conjunction with an experimental evaluation of the fundamental frequency of the site, from independent surveys, the wavelength-depth transformation can be used to get a direct and fast estimate of the position of the engineering bedrock
Geophysical monitoring of blast-induced liquefaction at the Mirabello (NE Italy) test site
No full textA blast-induced liquefaction test was conducted in the surroundings of Mirabello (NE Italy), where extensive liquefaction phenomena were observed after the 2012 Emilia earthquake. This experiment is the first blast-induced liquefaction test carried out in Italy. Several geophysical investigations were performed at the site to define initial soil condition and to evaluate the variations of the geophysical parameters over time. Specifically compressional (VP) and shear (VS) wave velocities were measured using both invasive (down-hole) and non-invasive (surface wave) tests. Electric Resistivity Tomography (ERT) tests were also carried out. Tests results before and after the blast-induced liquefaction are here presented and discussed with respect to the observed liquefaction effects. The evolution of measured geophysical parameters suggests that the soil modifications due to blasting (i.e., changes in porosity and soil structure) can be imaged with the adopted approaches
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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