1,721,410 research outputs found
A BAYESIAN MODEL FOR THE SHORT-TERM USE OF BUILDINGS AFFECTED BY AFTERSHOCKS
No full textSeismic risk is usually estimated under the hypothesis of stationarity. It is known that in some cases this is not sufficiently accurate. One example is the aftershock seismic risk evaluation, used to classify buildings, in terms of their usability. The proposed approach considers the occurrence of events as a Poisson process with variable rate. The number of events in the unit time is given by the Omori modified law and the magnitude distribution by the Gutenberg-Richter relationship. Since in the early days after the event, field data are not accurate enough to evaluate the model parameters, a Bayesian approach is used. The prior data, coming from the recent Italian sequences, and the posterior data, coming from the field, are merged, considering their uncertainties. An oriented NS fault (normal, inverse or strike slip) and a main shock of given magnitude is considered. Elastic spectral ordinates are attenuated from source to site, considering a given soil type. Buildings are considered to be uniformly distributed at every distance from the fault. Each building has similar seismic response, represented by a bilinear relationship. The performance point is obtained through the N2 method. The response of the damaged structure to aftershocks is still assumed bilinear, passing thorough the origin and the performance point in the main shock. For a given main shock, soil type and building type, uncertainties on the attenuation relationships, on the aftershock magnitude and epicentre and on the Life Safety limit state are considered. The probability of unusability in the main shock and in the aftershocks at each location from the epicenter, given the main shock, soil type and building type, has been evaluated. Results are sensitive to the exposure interval T1-T2, where T1 is the starting and T2 the ending time, measured from the main shock. The results are then compared against the minimum requirement concept, reported in ATC20 and in the Italian usability methodology. In the paper the full methodology is described and several important items are discussed, such as the effects of the spatial localization of strong aftershocks, the aftershock activity decay and the building resilience
RIFLESSI PROGETTUALI DEL DECADIMENTO DELLE CARATTERISTICHE MECCANICHE COME EFFETTO DI FATICA
No full textIL DECADIMENTO DELLE CARATTERISTICHE MECCANICHE DEL CALCESTRUZZO SOTTOPOSTO A FATICA HCF SI RIFLETTE SUL MODULO DI ELASTICITA' E SI INCROCIA CON IL COMPORTAMENTO VISCOSO
Performance of Lifelines During the 2002 Molise, Italy, Earthquake
No full textThe Molise earthquake affected a wide rural area with sparse houses, villages and towns. The paper investigates the response of water, electric power, telecommunications, natural gas, rail and motorway systems. Despite the amount of damage to buildings, lifeline systems reported only minor damage. The damage was light not only because the event caused relatively moderate ground motion in the affected area but also because the main lifelines do not cross the epicentral region and were in a fair state of maintenance. [DOI: 10.1193/1.1768542
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
Damage to buildings due to 1997 Umbria-Marche earthquake
No full textA short description of the structural damage to buildings, observed by the authors after the 1997 Umbria and Marche earthquake, is made. Buildings are grouped in four types, according to their seismic response. In the first type buildings of the historical centers, that have generally shown a good seismic behaviour, are included. A second type includes poor quality stone masonry buildings, heavily damaged by the earthquake near the epicenter. The buildings that were previously retrofitted and the reinforced concrete buildings are respectively included in a third and fourth building type
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
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