1,720,962 research outputs found
Optimization of a Stern-Gerlach Magnet by Magnetic Field-Circuit Coupling and Isogeometric Analysis
No full textStern-Gerlach magnets are used to magnetically separate a beam of atoms or atom clusters. The design is difficult, since both the magnetic field gradient and its homogeneity should be maximized. This paper proposes the numerical optimization of the device's pole-shoe shapes, starting from a reference geometry given in the literature. The main contributions of this paper are the generalization of a magnetic field-magnetic circuit coupling and the application of isogeometric analysis (IGA), which are shown to reduce the computational complexity and increase the accuracy. The field-circuit coupling significantly reduces the size of the field model part, in which the IGA's spline-based framework enables a highly accurate evaluation of local field quantities, even across elements
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
Numerical methods for the simulation of particle motion in electromagnetic fields
No full textIn questa tesi vengono studiati metodi numerici per la risoluzione di problemi in elettromagnetismo. Le principali applicazioni presentate provengono dall'ambito della fisica degli acceleratori ad alte energie. In questo contesto, viene confrontata l'efficienza di diversi metodi numerici per il calcolo delle traiettorie di particelle che attraversano il campo magnetico generato dal prototipo di un quadrupolo magnetico per il progetto High Luminosity - Large Hadron Collider (HL-LHC). Per la descrizione del campo è stato considerato un potenziale vettore in uno specifico Gauge che permette di ridurre il costo computazionale.
I risultati di questa prima analisi motivano lo studio sull'accuratezza dei metodi numerici per l'approssimazione del campo. È stato perciò sviluppato un nuovo tipo di discretizzazione per la ricostruzione del potenziale scalare magnetico in domini cilindrici e questo è stato applicato per la ricostruzione di un campo magnetico a partire da misurazioni realistiche utilizzando un metodo Bayesiano. Questo è stato confrontato con un metodo classico basato sulla separazione di variabili, evidenziando i benefici di questo nuovo tipo di discretizzazione e la sua applicabilità per la ricostruzione del campo.
La necessità di metodi efficienti per la descrizione dei campi elettromagnetici ha motivato l'estensione dello studio a generici domini assialsimmetrici, che hanno una forte rilevanza nelle applicazioni legate agli acceleratori di particelle. Viene perciò proposto un metodo basato sull'uso della serie di Fourier e dell'analisi isogeometrica (IGA) per sfruttare, da un lato, l'efficienza computazionale ottenibile grazie alla simmetria del dominio e, dall'altro, la possibilità di descrivere esattamente la geometria e le buone proprietà di approssimazioni tipiche dell'analisi isogeometrica. Con il metodo proposto è possibile formare un complesso di de Rham. Questa proprietà è cruciale per ottenere metodi numerici stabili che producono approssimazioni fisicamente corrette. Infine, Il metodo proposto è stato applicato per il calcolo dei modi risonanti in un cavità accelerante TESLA.In this thesis we study numerical methods for the approximate solution of problems arising in electromagnetism. Its main motivations come from applications to the modelling of high-energy particle accelerators. In this framework, we first compare the efficiency of several numerical methods for the omputation of particle trajectories in the design of a magnetic quadrupole for the High Luminosity - Large Hadron Collider (HL-LHC) project and we analyse the use of a specific vector potential gauge to reduce the computational cost. The results from this first comparison motivate the subsequent investigation of the accuracy of the numerical approximation of the field. We therefore develop a new type of discretization for the reconstruction of the magnetic scalar potential in cylindrical domains and we apply it to the field reconstruction from a realistic measurement process in a Bayesian framework. We compare this method with the reconstruction obtained by a more classical method based on the separation of variables, highlighting the benefits of the new type of discretization and its applicability to the reconstruction process.
Motivated by the need of efficient methods for the description of electromagnetic fields, we extend the study to other types of problems for axisymmetric domains, which have a high practical relevance in particle accelerator applications. In this context, we propose the use of a method based on the Fourier basis and IsoGeometric Analysis (IGA) to exploit, on one hand, the computational efficiency that can be achieved
thanks to the symmetry of the domain and, on the other, the exact representation of the geometry and the good approximation properties achievable in a IGA framework. Moreover, the proposed method forms a de Rham complex, which is a crucial property that allows to obtain a stable method which produces physically correct approximations. We finally apply the method to the computation of resonant modes of an accelerating TESLA cavity.DIPARTIMENTO DI MATEMATICA32SABADINI, IRENE MARIASABADINI, IRENE MARI
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
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