1,720,960 research outputs found
Design, realization and measurement of micro-magnetic radiators inside pipes filled with water
No full textThe paper presents the design, realization and measurement of micro magnetic antennas for the construction of wireless sensors and active RFID components. Small magnetic antennas are suitable for applications requiring the transmission through a dissipative medium. Furthermore, they exhibit a good omnidirectional radiation diagram and, especially for sensing applications, small antennas are necessary to reduce space occupation. Unfortunately, small antennas are characterized by light efficiency and high mismatch. This manuscript introduces an efficient way to reduce the overall antenna dimensions by selecting an efficient geometrical shape and embedding the matching circuit inside the antenna. The return loss has a 0.6% bandwidth at -10 dB, larger in comparison to other realizations than can be found in the literature. Although several realizations at different frequencies have been carried out, two solutions, at 433 MHz and 900 MHz, with simulations and measurements, are presente
An efficient technique for the design of miniaturized wireless sensors within liquids
No full textRecently, novel wireless sensor network architectures, suitable to monitor fluids characteristics from inside a conduit, have been proposed in the literature. These techniques require the implementation of a sensor equipped with an electromagnetic front-end able to transmit through a dissipative medium. This requires antennas with high transmission efficiency, even if inserted in liquids, in confined spaces, hence with high attention to the reduction of the dimensions. The present paper introduces an efficient design procedure that allows an easy and fast definition of the microwave circuit. The procedure is particularly suitable when the antenna is inserted in a complex scenario, with several media in the near field of the radiato
An Efficient Method to Design Planar Arrays for High Power Applications by Mutual Coupling Optimization
No full textInnovative ad-hoc wireless sensor networks to significantly reduce leakages in underground water infrastructures
No full textThis paper presents an ICT solution to overcome the problem of water dispersion in water distribution networks. Leakage prevention and breaks identification in water distribution networks are fundamental for an adequate use of natural resources. Nowadays, all over the world, water wasting along the distribution path reaches untenable percentages (up to 80 % in some regions). Since the pipes are buried within the terrain, typically only relevant breaks are considered for restorations: excavations are very expensive and consequently the costs to identify the position of the leakage or just the position of the pipe itself are too high. To address this problem, and simplify the leakage identification process, the authors have designed a wireless network system making use of mobile wireless sensors able to detect breaks and reveal unknown tracks and monitor the pressure spectrum of the fluid flowing in the pipe. The sensors transmit the acquired data from the terrain to the surface by use of a wireless connection. On the surface ground there are stations that receive the signal, process it, and communicate with a central unit where necessary intelligent signal processing techniques are used to detect leakage sources. Compared to other leakage detection solutions already available in the market (such as: Ground penetrating radar (GPR), pure acoustic techniques and tracer gases), the proposed technique appears very efficient and much more inexpensive
Wireless sensors as an efficient way to improve sustainability in water management by a significant reduction of water wasting
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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
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