1,720,979 research outputs found
Marine GIS as a Tool to Support Backscatter Data Analysis for Zooplankton Investigations
No full textEcho-sounders and Vessel-Mounted Acoustic Doppler Current Profilers (VM-ADCP) are widely operating onboard research vessels with the aim of providing real-time backscatter and ocean current profiles along the route, while the vessel is moving. Backscatter data are exploited to infer important information about zooplankton presence and distribution. Nevertheless, as these organisms daily vertically migrate even below the depth of the instrument range, the combination of space and time variability make their mapping from a moving vessel quite complex. The objective of this work is to describe a GIS application developed for the management and analysis of these data. The GIS capability as a tool to facilitate zooplankton investigations is assessed by means of a test-case in the area of the Ligurian Sea (Western Mediterranean) by using VM-ADCP backscatter data made available during oceanographic campaigns. The system, which includes a high-resolution bathymetry, environmental parameters, ephemeris, allows to select and visualize data sorted according to all the possible layer combinations. Moreover, different backscatter profiles, characterizing the identified migration phases can be enlightened by means of false color scale representation
A spar buoy-mounted ADCP measurement station in the Ligurian Sea: A metrological approach to correct current measures for bias effects and evaluate uncertainties
No full textSince the '70s, the ENEA Marine Environment Research Centre of S. Teresa has been involved in monitoring and analysis of physical, chemical and biological processes in marine environment. In order to provide a deeper view of the real marine dynamics, based on the integrated use of data and models, some of these activities have been recently focused on the measurement of current profiles in the open sea. A dedicated experimental methodology and data analysis were carried out to design and install a system for measuring current profiles in the surface layer in the Ligurian Sea: the measurement station, based on an Acoustic Doppler Current Profiler (ADCP) mounted on the surface buoy of W1-M3A (Western 1 Mediterranean Moored Multisensor) weather-oceanographic observatory, led to the acquisition of a time series of data continuously acquired for five months (from April to August 2017). The collected dataset, together with the implemented post-processing techniques, were aimed to realize a monitoring system able to support (and verify by comparison) marine current numerical models, with the final purpose of improving their performances. Main object of this work are both the correction of bias effects due to the buoy influence on ADCP measures and the evaluation of the overall uncertainty associated with the current velocities. In the following, an overall view of the performed experimental activity is briefly reported, ranging from the design of the measuring station to its implementation, from recovery to preliminary data processing and uncertainty analysis applied to a sub-set of data, used as a test case
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
A Supervised Learning Approach for Rainfall Detection From Underwater Noise Analysis
No full textUnderwater noise analysis allows estimation of parameters of meteorological interest, difficult to monitor with in situ devices, especially in very harsh environments such as polar waters. Rainfall detection is a fundamental step of acoustical meteorology toward quantifying precipitation and, indirectly, wind. To date, this task has been conducted with some success by using a few frequency bins of the noise spectrum and combining their absolute values and slopes into some inequalities. Unfortunately, these algorithms do not perform well when applied to spectra obtained by averaging multiple noise recordings made over the course of an hour. Supervised, machine learning models allow the use of all the frequency bins in the spectrum, exploiting relationships that are difficult for a human observer to identify. Among the different models tested, a binary classifier based on random forest performed well with moderate computational load. Using a dataset consisting of over 18 000 hourly averaged spectra (approximately 25 months of in situ recordings) and comparing the results with measurements from a surface-mounted rain gauge, the proposed system detects precipitations greater than 1 mm/h with 90% probability, keeping the false alarm probability below 0.5%. This system has demonstrated remarkable robustness as performance is achieved without intentionally excluding any spectra corrupted by sounds produced by other sources, such as naval traffic and wind blowing over the sea surface
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
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