1,722,007 research outputs found
Grid Assembly-Free 60-GHz Antenna Module Embedded in FR-4 Transceiver Carrier Board
No full textA novel antenna module solution which dramatically alleviates cost and fabrication related limitations of traditional 60-GHz antenna modules is demonstrated. The antenna topology is wholly devised using industry standard FR-4 PCB and is integrated into the 60-GHz transceiver carrier board. As a result, the proposed approach effectively bypasses the need for any complicated grid array assemblies for the first time to the author's best knowledge. The antenna element is first designed and confirmed to exhibit more than 9-GHz bandwidth and 71% average radiation efficiency from 57-66 GHz. The design is further expanded into an 8-element phased array module and integrated with a 60-GHz RFIC transceiver and digital interface. The overall footprint of the antenna module within the carrier board is 20 x 20 x 0.838 mm(3). System-level evaluation confirms the 8-element phased array module to be highly sufficient in scan range, side lobe levels and radiation efficiency for 60-GHz wireless systems, particularly in the field of consumer electronics.111213sciescopu
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
Radiation Efficiency-Improvement Using a Via-Less, Planar ZOR Antenna for Wireless ECG Sensors on a Lossy Medium
No full textThe critical issues involving severe radiation efficiency degradations during wireless electrocardiogram (ECG) health monitoring sessions are addressed by devising a monolithic zeroth-order resonance (ZOR) antenna. The presented antenna consists of a composite right/left-handed (CRLH) structure that is realized on a single, planar surface of the flexible printed circuit board (PCB) without the use of any via-holes. This significantly alleviates the complexity and fabrication cost involved with vertically polarized antennas with monopole-like radiation patterns, which are important factors in consumer electronics. Moreover, this letter investigates the practical issues associated with effects of the in-house designed ECG device circuit board, feeding mechanism with the RFIC, as well as the polycarbonate chassis. The finalized antenna is less than in total horizontal dimension with zero height profile. Measurement confirms the presented antenna features more than 30% radiation efficiency across 80 MHz bandwidth when completely integrated within the ECG sensor device and placed on the human body phantom.110sciescopu
Measurement accuracy enhancement using an optical probe system for electrically small MIMO antennas
No full textWell-known measurement inaccuracy issues for electrically small multiple-input-multiple-output (MIMO) antennas incurred by conventional metallic cable and feed effects are mitigated by adopting an optical probe based measurement method. To demonstrate this, a closely packed MIMO antenna consisting of a pair of spirally wound antenna elements is designed and characterized using both the metallic cable feeding and the optical probe feeding methods. The measured MIMO antenna parameters, such as envelope correlation, radiation efficiency, and diversity gain, ascertain significantly improved agreement with simulation, when the optical probe feeding method is used. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:238-241, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27302110sciescopu
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
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