1,721,003 research outputs found
Design and Implementation of Reconfigurable and MIMO Antennas for Future Heterogeneous Wireless Systems
No full textThe recent progress in electronics and communication technologies has driven the unprecedented demand for multi-functional wireless communication in most single wireless devices. However, employing the limited spectrum effectively on communication equipment poses a key design challenge, as most antennas often suffer from bandwidth limitations and restricted frequency rarge. Onekey approach to overcome this problem without significantly affecting the antenna size is to apply antenna tuneability and reconfigurability. This is achieved by electronically changing some properties of the antenna usually by loading the reactive loading of the resonator by means of active electronic elements including varactor diode or PIN diode with extra circuitry.
The main objective of this research is to design and investigate low-profile antennas for heterogeneous wireless systems using the antenna reconfigurability concept through tuning and/or using the MIMO antenna techniques. The research focuses on antenna design and implementation to cover various wireless standards and applications within the electromagnetic spectrum including UMTS (1.92-2.17 GHz), Cognitive Radio such as WLAN and WiMAX (2.4GHz), Wi-Fi (5.2GHz), 5G (600MHz - 6GHz) and MBAN applications. A family of compact microstrip printed reconfigurable antennas for various cognitive radio applications is presented. Effects of various slots on the antenna performance are also investigated, and the final version was reconfigured across a broad frequency range (1.5 - 2.4 GHz)
Furthermore, four new variants of the miniaturised hexagonal-shaped monopole printed antennas for different UWB applications are proposed. Prototypes of the four versions are fabricated and compared to establish their results. Two reconfigurable rejection bands are introduced to avoid anticipated interference with other systems working within the UWB range.
Finally, a novel low-profile four-element MIMO antenna was designed and fabricated to operate at the 2.4 GHz ISM band. both measurements and simulation results revealed strong agreement. Furthermore, the designed antenna was also tested on human tissues, with acceptable results when compared to its performance in free space. it is proved to be a good fit for wireless, mobile communications, medical systems and WBAN applications.Libyan Ministry of Higher Education.Subtitle: Simulation and Measurement of Reconfigurable Antennas for Cognitive Radio, UWB Applications, Investigation of Antenna Gain and Efficiency, Frequency Tuneable Range, Antenna Radiation Performance and Antenna Design Optimization using Parametric Studies as well as using MIMO antenna for wireless body area network
Investigation, design and implementation of frequency tuneable antennas for mobile handset and UWB applications. Simulation and measurement of tunable antennas for handheld mobile handsets and UWB system, investigations of frequency tuneable range, antenna radiation performance and antenna design optimisation using parametric studies
No full textGeneral Secretariat of Education and Scientific Research, Libya.The only available copy is the print version kept in the J.B.Priestley Library for reference
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
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