1,720,970 research outputs found
Optimal Design of an Ultra-Wideband Antenna with the Irregular Shape on Radiator using Particle Swarm Optimization
No full text[[abstract]]An ultra-wideband antenna with an irregular shape radiator for ultra-wideband applications has been designed by particle swarm optimization along with the simulator, HFSS. The proposed antenna design process is automated. Also, the better results can be obtained efficiently. The proposed antenna is fed by a coplanar waveguide line. The optimized antenna has a compact substrate size of 34.0 mm by 33.35 mm. Results show that the optimized irregular shape of the proposed antenna outperforms the antennas with uniform rectangular shapes in impedance matching. The optimized antenna can cover the spectrum of ultra-wideband (3.1 GHz - 10.6 GHz). The current distributions are investigated for describing the antenna characteristics. Moreover, the proposed UWB antenna has good characteristics of radiation, transmission, and impedance bandwidth.[[note]]SC
DESIGN AND OPTIMIZATION OF A LOGO-TYPE ANTENNA FOR MULTIBAND APPLICATIONS
No full text[[abstract]]This study respectively uses two optimizers, iterative Taguchi's method and particle swarm optimization, combined with the method of moments to optimize a logotype planar antenna for multiband applications. The proposed antenna consists of four metal letters, NCNU, which is the abbreviation of the authors' university name. This antenna can be used for university logo or advertisement applications. The antenna also serves as an example to compare the optimization performance of these two optimizers. Optimization results show that Taguchi's method achieves much better optimization performance than particle swarm optimization. This study also investigates the electromagnetic characteristics of the proposed antenna by parametric study using simulation. The presented optimization methods could be applied to designing similar logotype antennas.[[note]]SC
A COMPACT OPEN-ENDED SLOT ANTENNA DESIGN FOR ULTRAWIDEBAND APPLICATIONS
No full text[[abstract]]A compact size slot antenna designed for ultrawideband (UWB) applications is proposed. The slot embedded into the antenna was comprised an open-ended hemicircular slot and a narrow rectangular slot. To achieve good impedance matching within the desired band of interest, the 50 Omega microstrip feed-line is loaded with an elliptical slot, while an extended substrate was protruded above the upper edge of the antenna. The experimental results such as return losses, radiation patterns, and gain properties are studied, and good characteristics are demonstrated. Typical frequency domain responses are also measured to ensure that the proposed antenna can provide stable signal transmission within the UWB spectrum. (C) 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:86-91, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26514[[note]]SC
Optimal Design of CPW Slot Antennas Using Taguchi's Method
No full text[[abstract]]In this study, a one-element coplanar-waveguide (CPW) slot antenna and a two-element series aperiodic CPW slot antenna array are optimized by Taguchi's method, in conjunction with a full-wave simulator to analyze the antennas, to achieve the desired goals. As a comparison, particle swarm optimization (PSO) is also used to design the two antennas. Optimization results show that the desired frequency responses of the antenna are successfully achieved by the two approaches. The optimization results from the Taguchi's method significantly outperformed the PSO method in these two slot-antenna configurations.[[note]]SC
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
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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