1,721,069 research outputs found
Wireless Passive RFID Crack Width Sensor for Structural Health Monitoring
No full textAll mechanical structures are subjected to deformation and cracks, due to fatigue, stress, and/or environmental factors. It is, therefore, of uttermost importance to monitor the mechanical condition of critical structures, in order to prevent catastrophic failures, but also to minimize maintenance costs, i.e., avoid unnecessary inspections. A number of technologies and systems can be used for this purpose: among them, the ones proposing the use of wireless passive crackmeters have a strong impact potential, in terms of simplicity of installation and measurement and low cost. This paper, hence, shows a crack width wireless radio-frequency identification sensor, developed for applications on various materials (such as concrete and metal) and able to detect submillimeter deformations occurring on the object, on which it is placed. A design method based on high-sensitivity phase detection is shown
Constrained Pole-Zero Synthesis of Phase-Oriented RFID Sensor Antennas
No full textPassive sensing by means of Radiofrequency Identification
has been extensively explored for various application,
such as gas detection, temperature change and deformations.
The sensing indicator is generally based on the amplitude and phase of the backscattered field. However, a degradation of the communication performance must be usually accepted for achieving the sensing capability. This work introduces a design method suitable for phase-based RFID sensors that permits to shape the phase response while preserving the impedance matching between the antenna and the microchip. The RFID sensor is modeled as a two-ports scatterer comprising a lumped sensor at one of the ports and a RFID chip at the other port.
A pole-zero representation of the electromagnetic interaction between the reader and the RFID sensor allows to introduce a constrained design of the antenna with a full control on the sensor dynamic range and on the communication performance. The proposed method is numerically and experimentally validated by means of a pair of strongly coupled dipoles connected to a
voltage-controlled varactor emulating a dynamic sensor response
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
Setup-Independent Phase-Based Sensing by UHF-RFID
No full textAbstract--- By processing the phase of the backscattered field from an RFID-UHF tag antenna, physical information can be derived about the change of the materials and boundary conditions around a sensor-less tag. The phase-based sensing however is strongly referred to the specific set-up arrangement and huge artifacts would arise in successive independent measurements involving temporary (hand-held) readers. The paper introduces a multi-port tag arrangement suitable to achieve distance-independent measurements. The method exploits the use of sensitive and reference tags. Their phase responses are combined within a Double Phase Difference metrics suitable to robust data-inversion. The method is demonstrated through an experiment with a displacement-sensing system
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
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
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