1,721,003 research outputs found
L’ORO, IL BIANCO CALCE E LA POLVERE DI MARMO Stucchi e stuccatori nella Vicenza del Palladio
No full textRigorous modeling of mid-range wireless power transfer systems based on Royer oscillators
No full textResonant Wireless Power Transfer over variable distances requires adaptive frequency change in order to preserve efficiency. The Royer oscillator provides the capability of correctly tracking the most efficient resonant frequency without the need of cumbersome control systems. In this paper, a rigorous modeling, including frequency-dependent losses, of a wireless power transfer system based on Royer oscillators is presented and experimentally verified
A MEMS-Based Wide-Band Multi-State Power Attenuator for Radio Frequency and Microwave Applications
No full textIn this work we present a novel implementation of a multi-state RF (Radio Frequency) power attenuator, entirely realized in MEMS (MicroElectroMechanical-Systems) technology. The network, based on a CPW (Coplanar Waveguide) structure and fabricated in FBK technology, features several resistors realized with an highly-doped poly-silicon layer. Each resistor can load the RF line or can be shorted, depending on the state (actuated/not actuated) of electrostatically controlled suspended membrane-based MEMS switches. The network realizes 128 attenuation levels with flat characteristics over broad frequency ranges. The network features two sections, namely a series and a parallel one, that are experimentally characterized in a few of the possible configurations up to 30 GHz and simulated within CSTTM Microwave Studio. After validating the simulated results for the two sections, simulated results of the whole RF-MEMS-based power attenuator are presented and discussed
Power-Handling Capabilities Optimization of MEMS-Reconfigurable Antennas
No full textThe paper discusses a rigorous simulation of reconfigurable integrated antennas operated by MEMS switches, based on a combined nonlinear/electromagnetic (EM)/structural approach. The patch antenna is characterized as a linear multiport network by EM analysis. The MEMS are described as nonlinear components by means of their structural-based electromechanical equations. The accuracy of the nonlinear model is validated by comparison with measures. A rigorous analysis of the entire nonlinear (sub)system behavior is then performed by the harmonic balance (HB) technique combined with a numerical implementation of bifurcation theory. This allows an in-depth investigation of the complex stability pattern of the reconfigurable patch antenna including power-handling capabilities depending on MEMS switches position
Circuit-level nonlinear/EM co-simulation and co-design of UWB receivers
No full textThe paper describes an efficient and accurate circuit-level approach to the co-design of UWB receivers integrated with broadband antennas. A full nonlinear simulation of the front end is integrated with the electromagnetically (EM)-based description of the antenna impedance and far-field performance. For each direction of incidence of the transmitted UWB pulse, a circuit description of the receiver excitation under the form of a set of Norton equivalent current sources is generated by EM theory. The source internal impedance is the antenna impedance deter-mined by full-wave EM analysis. The receiver nonlinear analysis is carried out by a model-order reduction Harmonic Balance (HB) technique based on Krylov subspaces. The procedure allows the actual receiver sensitivity to be accurately evaluated by tak-ing into account the amplitude and phase distortion introduced by the antenna, which may significantly change with the UWB pulse direction of incidence. It also allows an effective prediction of the link power budget, which is particularly critical in ultra-low power Impulse Radio (IR) -UWB applications
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
Resonant Inductive WPT link with Load–Independent Voltage Gain
No full textThis paper investigates the possibility of achieving a load–
independent output voltage for a resonant inductive Wireless
Power Transfer (WPT) link
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
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