1,720,963 research outputs found
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Détecteurs moyen-infrarouge à multi-puits quantiques ultra-rapides, à base d'antennes patch
No full textThis Thesis is devoted to the conception, fabrication and experimental characterization of semiconductor-based ultra-fast photodetectors operating in the mid-infrared range (~3-12um). More specifically, the detectors that I have developed, generally known as multi-quantum-well infrared photodetectors (QWIPs), rely on intersubband (ISB) transitions in a GaAs-Al_0.2Ga_0.8As heterostructure, where an electron occupying the ground state of a quantum-well is photoexcited into an upper state, lying next to the energy continuum above the AlGaAs barriers.In my work I have exploited a specific device geometry that allows light-coupling at normal incidence, based on a two-dimensional array of electrically connected metallic patch-antennas. Each antenna is obtained by sandwiching the GaAs-AlGaAs multi-quantum-well heterostructure between a top contact metal layer and a bottom metallic ground plane, effectively forming a square metal-dielectric-metal microcavity, where the fundamental TM electromagnetic mode is resonant with the energy of the ISB transition. Finally, to allow for broadband microwave extraction, the antenna array is connected to a 50Ohm, monolithically integrated coplanar waveguide.In the first part of my work I have designed the antennas for optimum detection at 10um wavelength. This was done by running a set of simulations using a commercial electromagnetic solver based on the finite-difference time-domain (FDTD) method. Based on the results of the simulations I have fabricated a set of preliminary structures, without coplanar waveguide, to characterize the optical properties of the antenna array through Fourier transform micro-reflectance measurements. These measurements have allowed me to select the optimum patch array dimensions, namely the lateral size of the square-patch and the array periodicity.The second part of my work has been dedicated to the fabrication of the complete QWIP detector, including the monolithically integrated coplanar waveguide. In these detectors the size of the two-dimensional antenna array has been kept to a minimum, without compromising the radiation collection, in order to reduce as much as possible the device parasitic RC time constant and therefore maximize the detector speed. I have fabricated two generations of detectors relying on two slightly different active regions, respectively based on a bound-to-bound and a bound-to-continuum design. In the final part of my PhD I have also fabricated a third generation of devices, where the patch array, rather than to a coplanar waveguide, is connected to a spiral THz antenna. This device has not been characterized in this work and I present its relevance in the context of this Thesis in the perspectives.The last part of the Thesis is dedicated to the electro-optical characterization of the fabricated detectors. First, I have measured the dark current, the polarization dependence, and the dc photoresponse, that allowed me to determine the responsivity at 77K and 300K. Then I characterized the microwave frequency response of the detectors. To this end I have participated to the setup of an experimental apparatus based a high-speed (67GHz) cryogenic probe station. In this apparatus the beams of two quantum cascade lasers (QCLs) emitting at 10.3um wavelength, are simultaneously focused on the QWIP detector to generate a hererodyne signal at their difference frequency. By temperature/current tuning the emission wavelength of one QCL the heterodyne frequency can be swept continuously, thus allowing the measurement of the detector frequency response with the help of a spectrum analyzer. At room-temperature I obtain a flat frequency response up to 70GHz, solely limited by the bandwidth of the acquisition electronics. This is the broadest RF- bandwidth reported to date for a QWIP photodetector. To analyze the experimental data, I have modelled the electrical behavior of the QWIP using a small-signal equivalent circuit model.Cette thèse est consacrée à la conception, la fabrication et la caractérisation expérimentale de photodétecteurs ultra-rapides à base de semi-conducteurs fonctionnant dans le moyen infrarouge (~3-12um). Plus précisément, les détecteurs que j'ai développés, généralement appelés photodétecteurs infrarouges à multi-puits quantiques (QWIP), reposent sur des transitions inter-sous-bandes (ISB) dans une hétérostructure GaAs-Al_0.2Ga_0.8As, où un électron occupant l'état fondamental d'un puits quantique est photoexcité dans un état supérieur, se trouvant en proximit du continuum d'énergie au-dessus des barrières d'AlGaAs.Dans mon travail, j'ai exploité une géométrie de dispositif spécifique qui permet le couplage de la lumière à incidence normale, basée sur un réseau bidimensionnel d'antennes patch métalliques connectées électriquement. Chaque antenne est obtenue en intercalant l'hétérostructure multipuits quantique GaAs-AlGaAs entre une couche métallique de contact supérieure et un plan de masse métallique inférieur, formant ainsi une microcavité carrée métal-diélectrique-métal, où le mode électromagnétique TM fondamental est en résonance avec le l'énergie de la transition ISB. Enfin, pour permettre l'extraction de micro-ondes sur une large bande, le réseau d'antennes est connecté à un guide d'onde coplanaire 50Ohm, intégré de façon monolithique.Dans la première partie de mon travail, j'ai conçu les antennes pour une détection optimale à une longueur d'onde de 10 µm. Cela a été fait par le biais de simulations à l'aide d'un solveur électromagnétique commercial basé sur la méthode des éléments finis (FDTD). Sur la base des résultats des simulations, j'ai fabriqué un ensemble de structures préliminaires, sans guide d'onde coplanaire, afin de caractériser les propriétés optiques du réseau d'antennes par des mesures de micro-réflectance par transformée de Fourier. Ces mesures m'ont permis de sélectionner les dimensions optimales du réseau de patchs, à savoir la taille latérale du patch carré et la périodicité du réseau.La deuxième partie de mon travail a été consacrée à la fabrication du détecteur QWIP complet, y compris le guide d'onde coplanaire intégré. Dans ces détecteurs, la taille du réseau d'antennes bidimensionnelles a été réduite au minimum, sans pour autant compromettre la collection de la radiation incidente, afin de réduire autant que possible la constante de temps RC du dispositif et donc de maximiser la vitesse du détecteur. J'ai fabriqué deux générations de détecteurs reposant sur deux régions actives légèrement différentes, respectivement basées sur une transition ISB de type lié-lié et lié-continu. Dans la dernière partie de mon doctorat, j'ai également fabriqué une troisième génération de dispositifs, où le réseau de patchs, plutôt qu'à un guide d'onde coplanaire, est connecté à une antenne THz spirale. Ce dispositif n'a pas été caractérisé dans ce travail et je présente sa pertinence dans le cadre de cette Thèse dans les perspectives.La dernière partie de la thèse est consacrée à la caractérisation électro-optique des détecteurs fabriqués. Tout d'abord, j'ai mesuré le courant d'obscurité, la dépendance à la polarisation et la photoréponse continue, ce qui m'a permis de déterminer la responsivité à 77K et 300K. Ensuite, j'ai caractérisé la réponse en fréquence micro-onde des détecteurs. A cet effet, j'ai participé à la mise en place d'un banc expérimental basé sur une station sous pointes cryogénique large bande (67GHz). Dans ce banc, les faisceaux de deux lasers à cascade quantique (QCL) émettant à une longueur d'onde de 10.3 µm sont focalisés simultanément sur le détecteur QWIP pour générer un signal de battement hétérodyne à leur différence de fréquence. En changeant la température/courant d’un QCL, la fréquence de battement hétérodyne peut être balayée en continu, permettant ainsi d’obtenir la réponse en fréquence du détecteur à l'aide d'un analyseur de spectre. A température ambiante j'obtiens une réponse
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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