1,721,003 research outputs found
Contributi innovativi nel campo dell’Analisi Modale Operazionale finalizzati all’identificazione, al monitoraggio e alla damage detection in applicazioni ingegneristiche di frontiera = Novel contributions in the field of Operational Modal Analysis aimed at system identification, monitoring, and damage detection in challenging engineering applications
Full text linkIl presente programma di ricerca individuale si compone di contribuiti innovativi nel campo dell’Analisi Modale Operazionale (abbreviata in OMA) sviluppati in due branche fondamentali. La prima è dedicata alla formulazione della cosiddetta OMA vibro-acustica, quale metodologia semplice ed efficace per la caratterizzazione dinamica di microsistemi. Questa specifica metodologia di analisi modale output-only (la quale impiega un’eccitazione acustica, generata da altoparlanti, e sfrutta l’interferometria laser per la misura delle risposte) viene illustrata attraverso un esempio sperimentale relativo all’identificazione dei modi flessionali in-plane ed out-of-plane di un diapason in quarzo. In aggiunta, viene proposto lo sviluppo di una formulazione OMA detta “generalizzata”: essa mira a superare i principali svantaggi dell’OMA legati all’ipotesi di eccitazione ambientale che descrive le forze esterne quali rumori bianchi non correlati. Tale ipotesi viene difatti violata in tutti quei casi in cui i carichi operazionali sono caratterizzati da colorazione, componenti armoniche o qualsivoglia genere di correlazione (ne fanno esempio sistemi tipici dell’ingegneria meccanica quali veicoli o turbine eoliche). Nello specifico, la tecnica OMA proposta richiede una certa descrizione dei carichi agenti del sistema, risultando così applicabile a tutti quei sistemi per i quali certe caratteristiche degli ingressi sono note a priori. Si deriva, così, una decomposizione modale generalizzata delle funzioni di correlazione e delle densità spettrali di potenza relativamente alle sole risposte strutturali: tali modelli evidenziano una dipendenza non solo dai parametri modali ma anche da alcune caratteristiche spettrali degli ingressi e vengono quindi impiegati nello sviluppo di tecniche ad hoc per l’identificazione. La seconda branca di ricerca è dedicata ad una specifica classe di trasmissibilità, qui denominata come response-based frequency response functions (in breve R-FRFs). Essa approfondisce il processo di misura delle stesse R-FRFs per poi passare alla derivazione del relativo modello modale, impiegabile dai classici stimatori dell’analisi modale per l’identificazione di parametri modali aggiuntivi. Si dimostra, infatti, come i modi ricavabili dalle R-FRFs siano legati al sistema in esame quando considerato virtualmente soggetto a diverse tipologie di condizioni al contorno. Tale peculiarità denota un carattere locale di questi parametri modali addizionali, confermando la potenzialità delle R-FRFs nel campo della rilevazione di danni strutturali. Entrambi i filoni di ricerca sono corroborati da casi studio numerici e sperimentali, i quali offrono svariati scenari applicativi e risultati interessanti.In this dissertation, novel contributions in the field of Operational Modal analysis are presented in two principal branches. The former focuses on a vibro-acoustical OMA formulations as a simple and effective methodology for microsystems dynamic characterization. The particular output-only modal analysis methodology, that includes acoustical excitation via speakers and response measurements through a laser interferometer and microphone, is illustrated through the in-plane and out-of-plane flexural mode identification by experiment on high-quality factor quartz tuning fork (QTF). Additionally, a generalized OMA framework is proposed with the aim to overcome the main drawback of OMA approach consisting in the NExT assumption of uncorrelated white noises excitations. These hypotheses, in fact, are violated in all those cases in which the exerted environmental loads exhibit coloration, harmonic content or some kind of correlation, as in the cases of mechanical engineering systems like vehicles or wind turbines. Specifically, the proposed OMA technique requires some knowledge about the inputs acting on the system and, thus, it is applicable to systems for which something about the inputs is somehow known. The generalized modal structures of the output cross-correlation functions and power spectral densities are derived, as models showing the dependence not only by the modal parameters, but also by the input spectral characteristics, and employed in a customized identification technique. The second research offshoot is dedicated to a specific class of transmissibility functions, here called Response-based Frequency-Response-Functions (R-FRFs), and it comprises a first investigation on the estimation process of R-FRFs followed by a derivation of the relevant modal model, suitable for being tackled through frequency-domain estimators from the field of experimental and operational modal analysis, which let these additional modal parameters to be identified. It is demonstrated how modes retrieved from R-FRFs are related to the system under investigation, but, virtually, with a different set of boundary conditions. The particular properties give this additional modal parameters the advantage of being local, in turn confirming the significance of response-based frequency response functions in the field of damage detection. Both the research lines are corroborated by numerical and real-world experimental case studies that offer a number of application scenarios for results discussion
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
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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