1,721,368 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
Design of reconfigurable radiofrequency power amplifiers for wireless applications
No full textThe continuously growing throughput in wireless applications severely impacts the architecture and design of modern transceivers. One of the most challenging aspects is the design of the power amplifier (PA). Indeed, this block dominantly determines the overall transceiver power efficiency and therefore battery life-time. On the other hand, PA linearity is a key feature that limits the maximum allowed data rate. The goal of this thesis is to investigate and design novel smart architectures circumventing the stringent linearity/efficiency trade-off for third generation cellular and data transmission standards. A demonstrator has been developed on silicon (0.25µm BiCMOS ST Microelectronics technology), and has allowed validating the efficiency/linearity improvement principle.Abstrac
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
Conception de synthèses de fréquences à 24 GHz à base de diviseurs à mémoires D en technologies silicium avancées
No full textFrequency synthesis is almost used in all RF transceivers, where this function is usually achieved by using phase-locked-loop circuits. Most often, the phase-locked-loop includes digital frequency dividers in the feedback that present high power dissipation and low maximum frequency at gigahertz frequencies. This thesis presents a versatile new D latch-based divider that improves these issues and its application to frequency synthesis. The first part presents several frequency synthesis techniques and theirs main characteristics. Then is described various classical frequency dividers and the proposed new D latch-based SRO divider. A detailed study of the SRO divider is presented with two approaches, the digital one and the analogue one. This study demonstrates the benefit of the SRO divider in terms of power dissipation and speed compared with the widely used D flip-flop based dividers. The last part presents several implementations of the SRO divider in CMOS and BiCMOS processes of ST Microelectronics. Particularly, the SRO divider was implemented in two 24 GHz fractional synthesizers, where it demonstrates its interest for reduction of power dissipation while using small silicon area.La synthèse de fréquences est une fonction largement utilisée dans les émetteur-récepteurs radios. En général, la fonction synthèse de fréquence est réalisée à l’aide d’une boucle à verrouillage de phase utilisant des diviseurs de fréquence numériques. Cette thèse présente un nouveau type de diviseur de fréquence faisant appel à des mémoires D et son application à la synthèse de fréquences. Ce nouveau diviseur permet de repousser les limites des diviseurs numériques classiques à bascules D, en matière de fréquence maximale de fonctionnement et de consommation, tout en conservant leur souplesse d’utilisation. La première partie de cette thèse présente les techniques usuelles de réalisation des synthèses de fréquence et des diviseurs de fréquences, ainsi que le nouveau diviseur SRO à base de mémoires D, sujet de ces travaux. Une étude détaillée de ce diviseur est réalisée avec un premier modèle utilisant une approche numérique, puis un second plus réaliste faisant appel à une modélisation de type analogique. Cette étude démontre que ce nouveau diviseur SRO est capable de fonctionner à une fréquence plus élevée ou avec une consommation moindre, tout en réalisant les mêmes facteurs de division, que les diviseurs classiques à bascules D. La dernière partie de cette thèse présente plusieurs implémentations en technologies CMOS et BiCMOS de ST Microelectronics du diviseur SRO. En particulier son implémentation dans deux synthétiseurs de fréquences fractionnaires à 24 GHz montre son intérêt de part la réduction significative de consommation obtenue, tout en conservant une structure simple utilisant une surface de silicium réduit
Study of a Radio Frequency Front End (RFFE) based on Walsh sequences for the 5G standard and beyond.
No full textLes services de télécommunications mobiles ont besoin d’une augmentation continue et exponentielle de leurs capacités. Pour répondre à cette demande, les émetteurs-récepteurs doivent être hautement numériques et flexibles. Une solution prometteuse pour atteindre cet objectif est d'utiliser les séquences de Walsh pour générer des signaux arbitraires. On se base sur le principe d'un émetteur "radio logicielle" comprenant un DAC haut débit à haute résolution. Ainsi, l'architecture étudiée consiste en un DAC très large bande (0 à 6 GHz) très efficace pour une amplification RF directe avec pour cible les applications 5G dites de phase 1 et une mise en forme du signal à base de Transformée de Hilbert pour une montée en fréquences millimétriques (au delà de 20GHz) sans recourir à des techniques de filtrage complexes avec pour cible les applications 5G dites de phase 2 ou 6G. L'objectif de ces travaux est de proposer une nouvelle topologie d'émetteur qui répond à des problématiques telles que: la conversion massive de données (très haut débit), l'agrégation de porteuses et la linéarisation dynamique d’un frontal RF. Le candidat devra faire la démonstration de l'architecture proposée en utilisant la technologie 28nm FDSOI de ST Microelectronics. Le travail comportera des simulations haut niveau (MatLab), un dimensionnement de l'architecture, des simulations schematiques, des dessins de masques, une fabrication du circuit, une conception d'un environnement de mesures adéquat et des mesures exhaustives.Mobile telecommunications services require a continuous and exponential increase of their capacities. To meet this demand, transceivers must be highly digital and flexible. A promising solution to achieve this goal is to use Walsh sequences to generate arbitrary waveforms. This is based on the principle of a "software defined radio" transmitter comprising a high-speed, high-resolution DAC. Thus, the studied architecture consists of a very wide band DAC (0 to 6 GHz) very efficient for a direct RF amplification with 5G phase 1 applications as target and a Hilbert Transform based signal shaping for a millimetric frequency upconversion (beyond 20GHz) without resorting to complex filtering techniques with 5G phase 2 or 6G applications as target. The objective of this work is to propose a new transmitter topology that responds to issues such as: massive data conversion (very high throughput), carrier aggregation and dynamic linearization of an RF front end. The candidate will demonstrate the proposed architecture using ST Microelectronics 28nm FDSOI technology. The work will include high level simulations (MatLab), architecture sizing, schematic simulations, mask designs, circuit fabrication, design of a suitable measurement environment and comprehensive measurements
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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