1,721,002 research outputs found
An Alternative to Commercial Optical Fibre Sensors for Shallow Landslide Monitoring – Interferometric Optical Fibre Sensing
No full textOptical fibre-based monitoring has settled in the field of geohazards monitoring. Interferometric optical fibre sensors are the least used in landslide monitoring, while classical approaches rely on Fibre Bragg Grating and Brillouin Optical Time Domain Reflectometry/Analysis. Landslide monitoring goes hand by hand with the development of technology. While authors tend to focus on the unprecedented accuracy and reduced costs of the sensor itself, the economic and practical aspects related to the interrogating systems are often disregarded. Recently, a simpler and significantly more cost-effective approach has been introduced through “integral coherent measurements” because they yield an integral of the signal response over the entire length of the optical fibre sensor. This sensing system proves to be suitable to provide an overall indication of the state of the entire monitored domain and yield indications of the onset of motion with a high temporal resolution. The sensor has been tested in controlled conditions as a monitoring tool in a downscaled landslide model. We exploit the large bandwidth and high frequency of acquisition in order to detect high frequency elastic waves. The proposed sensor is able to distinguish the vibration footprint generated by ground movement. The results obtained from the experimental tests demonstrate that the proposed sensing system is able to recognize the onset of motion some minutes before a visual indication of instability could be observed
Enhanced Neural Network Implementation for Temperature Profile Extraction in Distributed Brillouin Scattering-based Sensors
No full textIn this work two Neural Network (NN) based solutions are proposed to recover the distributed temperature profile of a sensing fiber, measured using a commercial Brillouin Optical Time-Domain Analysis (BOTDA) interrogator. A detailed analysis in terms of temperature accuracy and processing speed is carried out for both the proposed methods, comparing the results with the ones obtained from the application of classical fitting techniques, namely cross-correlation (CORR), Lorentzian fitting (LF) and Pseudo-Voigt fitting (PV), through both simulations and real measurements carried out in laboratory environment. The results show that the first NN implementation, which aims to maximize the accuracy of the temperature profile and the processing speed, can handle different width of frequency acquisition window but needs to be optimized for a specific frequency acquisition scanning step. The second NN implementation, however, can also handle different values of the acquisition scanning step with a minor performance drop. Simulations and experimental data show a massive advantage of NN implementations in terms of processing speed with respect to classical fitting techniques, with a slightly better accuracy of the estimated temperature profiles
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
RSOA-based self-seeded transmitters: The ERMES project results and offsprings
No full textThe EU FP7 ERMES project focused on the development of a wavelength division multiplexed passive optical network (WDM PON) colourless self-tuning transmitter based on reflective semiconductor optical amplifiers (RSOAs) self-seeding. These transmitters represent low cost solutions to achieve self-organized wavelength access networks. The EU ERMES project developed self-tuning transmitters both in the C- and O- band with tens of kilometres reach up to 10 Gb/s. During the project we developed different self-seeding architectures with single RSOA exploitation (standard self-seeding) or two-RSOA exploitation (amplified or face-to-face self-seeding). The employment of Faraday rotators and mirrors in retracing configurations ensured polarization insensitive operation of the self-seeded architectures allowing for the exploitation of high gain C and O-band RSOAs, which present a very high polarization dependent gain. The project evaluated the coexistence of time division multiplexing (TDM) and WDM PON supporting high-numbers of users: although the burst mode operation was limited by the build-up time of the long-cavity laser, the rise time is compatible with a sleep mode for energy saving. After the project conclusion self-seeded transmitters have been exploited with alternative modulation formats including polarization division multiplexing and frequency division multiplexing in order to increase the achievable bit rates. Finally further studies to increase modulation cancellation inside self-seeded transmitters have been performed
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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