1,720,992 research outputs found
A NEW BROADBAND MICROSTRIP QUADRATURE HYBRID WITH VERY FLAT PHASE RESPONSE
Get PDFA new broadband microstrip branch-line quadrature
hybrid with very flat phase response is presented. The device is
made by cascading four branch-line couplers with arbitrary power
division. The novel design is based on the microstrip transposition of a
broadband waveguide polariser [4]. Across a 32% bandwidth centred at
9.3 GHz, the RL and the IL are respectively -15 dB and -3 dB/-4 dB;
the phase difference is very flat, i.e., 90°± 1.5°
A wideband quadruple-ridged horn antenna for the multifeed S-band receiver of the Sardinia radio telescope
Get PDFA feed horn for the multifeed S-band receiver of the Sardinia Radio Telescope (SRT) has been designed. The antenna consists of a truncated circular waveguide with four ridges of variable height inside. The horn antenna has been designed and tested using Ansys HFSS and, then, the multifeed system has been coupled with the SRT using GRASP by TICRA. The return loss of the feed horn is larger than 20dB over a 60% bandwidth (between 2.3 and 4.3GHz), and the edge taper and the cross-polarization level of the multifeed system meet the specifications of the SRT S-band receiver
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 microwave subsystems for radio astronomical receivers
Get PDFThe radio astronomical receivers are devices that they measure the radio emissions coming from celestial sources. Therefore, the aim of these devices is to convert the weak electromagnetic energy from space into a measurable electrical signal. The nature of the signal emitted by celestial sources imposes that such receivers must be broadband, very sensitive and designed to measure noise. In fact, the electromagnetic signal that the receivers must capture and measure, in addition to being very weak, is a random signal with components uncorrelated with each other, with different frequencies and with zero mean value (i.e. it is like the thermal noise produced by a resistor subject to a temperature). Therefore, the weakness and the peculiarity of these signals make the radio astronomy receivers other than those used in the telecommunications.
It is in this context that the work of my PhD thesis has been developed. Three different projects, that regard to the microwave subsystems of the radio astronomical receiver, have been treated.
The first project is focus on the development of a new configuration of broadband polarizer with very flat phase response in microtrip technology.
The second project is a feasibility study on the optics of a 3mm SIS receiver in order to install it in the Gregorian focus of the Sardinia Radio Telescope.
The third project is fully dedicated on the development of a high performance wideband feed-horn for a state-of-the-art multi-beam S-band (2.3 - 4.3 GHz) receiver to install in the primary focus of the Sardinia Radio Telescope
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
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
- …
