1,720,955 research outputs found
Frequency Diverse Array for Signal Geofencing in Wireless Communications: Does It Work ?
Full text linkFrequency Diverse Array is an advanced antenna technology for clustering received power spatial distribution in specific areas, which has shown significant potential in many applications, including radar or wireless power transfer. In wireless communications, signal geofencing might be beneficial in increasing communication secrecy or reduce interference issues, but system communications through frequency diverse arrays require careful consideration about several design parameters. In this paper, a detailed analysis of the sensitivity of the geofencing effectiveness to the main array parameters is carried out. The analysis covers many aspects of the design, including the selection of the geometrical layout and the number of elements of the array, the frequency increase policy and the frequency offset across the elements and their spacing. The study also discusses the trade-offs between different design choices and provides insights into the performance in terms of focus efficiency and size of the focus area. Results show that bidimensional layouts, e.g. circular or planar, often represent effective solutions, whereas the linear arrangement can be a viable option only in case the frequencies are spread across the elements in a random-like fashion. Frequencies are usually increased according to either a logarithmic or a linear policy. The linear solution in general yields lower performance, but also lower complexity. Frequency offset, number of elements and their spacing represent further project parameters. Finally, a preliminary assessment of the multipath effect on the focus task shows that the performance of frequency diverse arrays can be affected by complex propagation conditions and deserve further investigations
Origin and distribution of different types of sinkholes in the plain areas of Southern Italy
No full textSinkholes constitute a significant risk in many karst areas, and may even, threat human safety, Collapse sinkholes that occur catastrophically without showing premonitory signs may result in severe economic losses and casualties. In the last years, research on sinkholes and related detrimental effects has significantly increased in Italy, in the aftermath of remarkable events. Aimed at analysing the peculiar conditions which lead to sinkhole occurrence in Southern Italy, a set of cases in the plain areas of Campania, Apulia and Calabria is discussed, The considered regions show a wide variety of environmental conditions. In Campania, the plains are underlain by alluvial deposits with, intercalations of volcaniclastic sediments. Sinkholes are generally located along the Tyrrhenian margin, of the carbonate massifs or within intramontane Apennine basins. In Apulia, a flat and elongated, peninsula, most of the cases occur on calcarenites overlying limestone bedrock along the coast. In Calabria, one of the most seismogenic Italian regions, the surveyed cases seem to be attributable mainly to earthquake-induced liquefaction. The article provides a first glance on the variety of sinkholes in the plain areas of Southern Italy, to highlight the possibility of further subsidence events in the considered regions, as well as in other comparable areas of the country. © 2010 Lavoisier SAS. All rights reserved
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
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
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