1,720,984 research outputs found
Millimeter-Wave Microstrip to Waveguide Transition for use in Gap-Waveguide-Integrated Grid Amplifiers and Antenna Arrays
Get PDFTo realize next generation mm-wave wireless systems it is vitally important to utilize cost effective manufacturing technologies and to develop low-loss waveguides and transmission lines. Furthermore, being able to interface system components through contactless transitions is another key objective. In fact, recently, optical connections between chips through fibers is being researched heavily in the photonics science field, while the quasi-optical connection as proposed in this MSc thesis between chips through waveguides presents a similar breakthrough, albeit in the mm-wave range. The proposed contactless connection between a waveguide and chip obviates the need to use RF bond wires. Furthermore, the proposed solution is also compatible with the gap waveguide technology enabling the resonance-free electromagnetic packaging of the entire RF front end.\u3cbr/\u3eThere are numerous challenges to overcome to realize future mm-wave antenna systems. Standard waveguide components are rather low loss but are manufactured in split blocks which may lead to power leakage. Mechanical assembly of the two split blocks requires a very good electrical contact as well as precise alignment of the two blocks to achieve good electrical performance. Furthermore, the physical dimensions of the waveguide components decrease as the frequency of operation increases. This renders the manufacturing of conventional waveguide components more costly and time consuming, particularly at mm-wave frequencies.\u3cbr/\u3eThe gap waveguide structure has the advantage of reducing the manufacturing cost and time, because the gap waveguide structure can be realized without requiring any metal contact between the upper and the lower metal surfaces of the structure. Also, the Perfect Magnetic Conductor (PMC) condition realized by the lid of nails, parallel to a PEC surface, has the ability of suppressing unwanted parallel-plate modes between the two metal blocks and allows for the resonance-free packaging of RF electronics, thereby high isolation between the RF components can be achieved.\u3cbr/\u3eAt the same time a low-loss transition between the gap waveguide components and the active ICs, such as Monolithic Microwave/Millimeter Integrated circuits (MMIC), is necessary in order to integrate active components with passive waveguide components together with antennas in a single module. It is common practice to establish a connection between a transmission line and a chip through RF bondwiring. However, the large impedance mismatch between the inductive bond wire and the MMIC requires a matching capacitor. But impedance matching can only be achieved over a certain bandwidth, depending on the Q-factor of the LC circuit. Furthermore, the matching network takes up the space, and may excite cavity modes when packaged resulting in device oscillations and cross talk effects. It is therefore the objective of this thesis to provide a novel, low-loss and broadband contactless microstrip line to groove gap waveguide transition.\u3cbr/\u3eAn MMIC-to-waveguide transition has been designed at W-band and in such a way that it can be integrated easily in a groove gap waveguide structure, for example by using a pick-and-place technique. Both the PCB and the gap waveguide were designed and manufactured. Tolerances are allowed up to ± 10 microns. The simulation results of a back-to-back transition are excellent; the S11 is below -21 dB, while S21 is better than -0.35 dB over the entire W-band (75-110 GHz). Unfortunately the experimental validation of the transition is not as expected. A thorough error analysis revealed that the dimensions of the PCB were not within the tolerances as specified by the manufacturer, which is the main reason for the performance degradation. Future steps are recommended to resolve these issues
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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