1,720,974 research outputs found
Approcci innovativi all’identificazione dinamica delle strutture e del danno strutturale per le costruzioni in muratura
No full textIl presente lavoro riguarda lo studio e lo sviluppo di approcci innovativi all’identificazione dinamica delle strutture e del danno strutturale per le costruzioni storiche in muratura. Il patrimonio storico architettonico, prevalentemente costituito da costruzioni in muratura, rappresenta una parte fondamentale del patrimonio culturale di una nazione; la sua salvaguardia è dunque un’attività strettamente necessaria per la conservazione nel tempo dell’identità culturale dei popoli. Questa necessità si scontra spesso con la scarsa conoscenza del comportamento strutturale di questo genere di costruzioni. Le tecniche di identificazione dinamica delle strutture e del danno si inseriscono in questo contesto. Il loro utilizzo combinato, infatti, consente di ottenere informazioni sulle caratteristiche meccaniche globali e locali delle strutture, necessarie a calibrare i modelli strutturali e progettare interventi di conservazione mirati ed efficaci. Tuttavia, queste tecniche presentano ancora diverse problematiche che ne limitano l’applicazione alle costruzioni in muratura: il tradizionale set-up sperimentale per l’identificazione dinamica delle strutture è alquanto complesso e impegnativo; inoltre, gran parte delle tecniche di identificazione dinamica del danno è troppo generale e non tiene conto delle peculiari caratteristiche di queste costruzioni.
In questo lavoro vengono proposte soluzioni originali ad entrambe le problematiche, attraverso la combinazione di approcci teorici originali e di tecniche sperimentali avanzate, applicate in modo innovativo. Per l’identificazione dinamica delle strutture, sono state esplorate le potenzialità e i limiti dell’interferometria radar, una tecnica innovativa per la misurazione a distanza delle vibrazioni strutturali. In particolare, considerata l’incapacità di ricostruire lo sviluppo tridimensionale e spaziale delle forme modali di una struttura con un solo interferometro, sono stati sviluppati modelli teorici e approcci sperimentali speditivi che prevedono l’utilizzo simultaneo di due interferometri. Per l’identificazione dinamica del danno, dato il ruolo portante che gli archi rivestono all’interno delle costruzioni in muratura, è stato sviluppato un approccio ad hoc che, dalla variazione delle frequenze naturali, permette di localizzare e quantificare danni multipli in questi elementi strutturali. L’approccio è stato sviluppato considerando le principali caratteristiche strutturali degli archi in muratura e dei fenomeni di danneggiamento di maggiore rilevanza per tale tipo di strutture. Tutti gli approcci proposti sono stati validati attraverso prove sperimentali in laboratorio e in situ.This work concerns the study and development of innovative approaches to dynamic structural identification and dynamic damage identification for masonry constructions. The architectural heritage, mainly composed of masonry constructions, represents a fundamental part of the cultural heritage of countries; therefore, its preservation is an essential goal for our society and for the scientific community. Anyway, one of the most critical issue is the lack of knowledge on the structural behavior of these constructions. Dynamic testing and dynamic-based structural damage identification techniques could play a major role for overcoming this obstacle. Indeed, the combined use of these techniques makes it possible to get information about the global and the local structural features, essential for calibrating structural models and designing specific and effective conservation interventions. However, these techniques still show some drawbacks which hinder their application to masonry constructions: the traditional experimental setup for dynamic testing of structures is complex and highly demanding; moreover, most dynamic-based damage identification methods are too general and do not take into account the peculiar characteristics of masonry constructions.
This thesis proposes original solutions to both problems, through the combination of original theoretical approaches and advanced experimental techniques, applied in an innovative way. As to dynamic testing, the potentials and limitations of the radar interferometry – a highly innovative technique for remotely measuring structural vibrations – were explored. In particular, because of the inability to reconstruct the three-dimensional and spatial characteristics of mode shapes of structures by using a single radar interferometer, theoretical models and expeditious experimental approaches involving the simultaneous use of two radar interferometers were developed. As to dynamic-based structural damage identification techniques, due to the fundamental role played by arches in masonry constructions, an ad hoc natural frequency-based approach for the localization and quantification of multiple damages in masonry arches was proposed. This approach has been developed considering the main structural features of blocky masonry arches and the most relevant damage phenomena possible for this type of structures. All of the proposed approaches have been validated through laboratory and in situ experimental tests
PSG (Pad System for Georadar), a new positioning system to perform 3D georadar investigations for utility mapping
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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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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