1,720,957 research outputs found
SEABED NATURE AND MORPHODYNAMICS: HIGH RESOLUTION INTEGRATED ACOUSTIC DATA ANALYSIS
No full textGli ecoscandagli multibeam non sono solo in grado di acquisire dati batimetrici ad alta precisione ma anche di registrare l’intensità del backscatter del fondale ad alta risoluzione. Molti studi sono stati effettuati sul “remote sensing” acustico con lo scopo di classificare il fondale tramite il dato di basckscatter (approccio unsupervised) ed ottenere una rapida, aerea e possibilmente migliore classificazione rispetto il tradizionale campionamento diretto (approccio supervised).
Tramite l’integrazione di dati e l’impiego di tecnologie che consentono il seabed mapping è possibile ottenere uno studio ad alta risoluzione della morfologia del fondale, discriminando feature di fondo e habitat a differenti scale spaziali, a varie profondità e con differenti tipologie di fondale (morfologia e materiali) come i banchi di corallo profondi nel Canyon di Levante (Mar Ligure), il complesso vulcanico di Panarea (Isole Eolie, Mar Tirreno) o evidenziare le dinamiche ambientali nel tempo e nello spazio tramite il monitoraggio idrografico dell’evoluzione del fiume Magra e della costa adiacente. Questo specifico obiettivo è stato raggiunto grazie all’analisi delle serie storiche di dati dell’Istituto Idrografico della Marina e rilievi più recenti resi comparabili poiché conformi al medesimo standard idrografico. Infatti i dati analizzati sono stati raccolti negli ultimi 135 anni con differenti strumenti (dal filo a piombo al multibeam), scale e elaborazione.
Il metodo impiegato per questa ricerca idrografica è basato sulla integrazione di dati ed un approccio iterativo a diverse scale al fine di individuare le aree da investigare ulteriormente con sistemi a differente risoluzione e massimizzare così l’impiego delle risorse e dei dati a disposizione.The multibeam echo sounder system can not only obtain high-precision seabed bathymetry data, but also high-resolution seabed backscatter strength data. A number of studies have applied acoustic remote sensing method to classify seabed sediment type with multibeam backscatter strength data (unsupervised), and to obtain a rapid, areal and therefore better classification results than the traditional sediment sampling method (supervised).
Through data integration and the use of seabed-mapping technologies it is possible to obtain a high-resolution (HR) study of seabed morphology and nature, discriminating specific targets, benthic features and habitats at different spatial scales in various water depth and bottom types (morphology and materials) such the deep coral banks in the Levante Canyon (Ligurian Sea), the volcanic complex of Panarea (Eolian Islands, Tyrrhenian Sea) case studies or highlighting the environmental dynamics trough time and space using hydrographic monitoring like the evolution of the Magra River and its adjacent Ligurian coast. This specific goal was achieved processing the historical data series stored in the archive of the Italian Hydrographic Institute and more recent surveys. Data are completely comparable because they follow the same hydrographic standards during time. In fact, the data available were collected in the last 135 years with different equipment (from lead line to acoustic multibeam system), scale and processing. The method used for this hydrographic research is based upon data integration and multiple focusing approaches to identify areas to be investigated with different resolution systems in order to perform data exploitation and multiple usages of available resources
Last century seabed morphodynamics of the Magra River estuary (Western Mediterranean Sea)
No full textThe estimation of morphological and volumetric changes of the delta system at the mouth of the Magra River is
presented in this paper using bathymetric and sedimentological data. The data series were collected during several
hydro-oceanographic surveys carried out from 1882 to 2014, processed following the hydrographic international
standards and stored in the Italian Navy Hydrographic Institute database. In particular, bathymetric data characterized
by the same standard and accuracy were collected using different devices such as sounding lines, single-beam
and multi-beam acoustic system. This research compares Digital Terrain Models (DTMs), derived from highly
accurate bathymetric data and covering different time scales (secular, half-century and decade) in order to assess
and quantify the seabed morphodynamics in relation with the river sedimentary budget. The methodology and data
exploitation consist mainly in the production of DTMs to study the elevation change, two-dimensional and three
dimensional maps, cross-sections of the seabed, difference surfaces and computation of net volumes as well as
an historical sedimentological map. These products are also an useful contribution to the aim of EU RISC-KIT
Project. The results of the analysis highlight changes in the geometry of the Magra River mouth, of the coastal
profile and bottom features primarily due to variations of the sedimentary budget and secondarily to wave dynamics.
This behaviour is characterized by evident river mouth and coastal retreat, beach erosion and sediment bars
decay and net accretion under periods of high river sediment discharge and elongate bar formation during relatively
fair conditions. In the last century the main change is constituted by the disappearance of the typical constructive
seabed delta morphology and the transformation into the current small estuary, with microtidal condition. This
small estuary has an upper sector where river processes, sediments and bedforms dominate, a lower sector near the
mouth, where wave and tidal processes and marine sediments dominate, and a middle sector, where tidal currents
dominate and both river and marine sediments are present
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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