1,721,116 research outputs found

    Channel characterization at 2.4 GHz for aerial base station

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    The paradigm shift towards high data rate demands of mobile users in IMT-2020 commonly known as 5G, led to the possibility of using Aerial Base Stations (ABS) to fulfill such requirements. However, for implementation of ABS, an appropriate air-to-ground channel model is needed. It is an important factor to incorporate the understanding of the channel fading behavior before designing the system. In this article, we present novel channel propagation results obtained from ray tracing simulations for different environments, such as Suburban, Urban and Urban-High-Rise, according to ITU Radio-communication parameters. The details of different channel characteristics such as Spatial Correlation and Cumulative Distribution Function for Small Scale Parameters as Delay Spread and Angle-of-Arrival are presented for different ABS heights. We also focus on various channel modeling approaches and frameworks for 3D channel models

    Efficient and environmentally friendly techniques for extracting lignin from lignocellulose biomass and subsequent uses: A review

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    The development of sustainable and effective methods for extracting lignin is crucial for achieving the advantages and promoting the shift towards a more sustainable and circular bioeconomy. This study addresses the use of environmentally friendly processes, including organosolv technique, supercritical fluid (SCF), non-thermal plasma (NTP), ionic liquids (ILs), deep eutectic solvents (DES), and microwave assisted extraction (MAE) techniques for lignin extraction. Organosolv treatment offers high selectivity and purity of lignin make this process economically feasible. Using supercritical water, carbon dioxide, or ethanol to extract lignin without harmful solvents is successful and customizable. NTP technologies break down lignin, simplifying processing and increasing its value. Whereas ILs may boost lignin synthesis and change its properties via solvent design. DES-based extraction methods can efficiently and specifically extract lignin. The rapid and effective MAE method employs microwave radiation to reduce extraction times and boost yields for lignin extraction. These methods feature high selectivity, little environmental impact, and the capacity to target lignin fractions. The study describes the fundamentals, benefits, and drawbacks of each extraction process, focusing on their ability to extract lignin on a large scale and its future usage. Additionally, this review explores the most recent advancements in the application sector, as well as the challenges and potential advantages of valorizing streams derived from extraction, thereby fostering the development of environmentally friendly and sustainable solutions. This research concludes that to overcome future challenges, need to address scale concerns, cost, emissions, and efficient lignin use

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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
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