1,720,986 research outputs found
The Application of Video-Monitoring Data to Understand Coastal and Estuarine Processes
No full textLa presente tesi riguarda l’uso dei dati raccolti da una nuova stazione di video monitoraggio, denominata SGS allo scopo di accrescere la conoscenza dei processi idro-morfodinamici caratteristici di una spiaggia sabbiosa naturale tipica della costa Adriatica, in prossimità di un estuario. La stazione è stata installata all’interno del porto di Senigallia e ogni ora registra un video di dieci minuti a 2Hz. In questa tesi, sono stati elaborati i video raccolti dal 2015 al 2017. Le immagini derivanti sono state utilizzate in due differenti analisi: 1) lo studio della capacità di stimare la batimetria applicando il codice cBathy (un algoritmo ampiamente utilizzato per la valutazione della profondità dell’acqua tramite analisi inversa) ai dati ottici provenienti dalla stazione e 2) lo studio della dinamica di un sistema di barre sommerse. La stima della profondità dell’acqua varia, in termini di qualità, in funzione della posizione spaziale e delle condizioni ondose e si è osservata una generale sottostima della profondità in gran parte del dominio. Si è quindi eseguita una dettagliata analisi per comprendere il motivo di tale risultato. La causa principale è stata attribuita al grande angolo presente tra l’asse ottico della telecamera e la direzione di propagazione delle onde incidenti. Dei test sintetici sono stati usati per analizzare più in profondità questo aspetto. La procedura utilizzata può essere applicata anche per il progetto di nuove stazioni di video-monitoraggio. Per quanto riguarda la seconda analisi, le immagini disponibili permettono di ben identificare la complessa variabilità 3D (commutazione e biforcazione) del sistema di barre sommerse, sottolineando la capacità della stazione SGS di monitorare le caratteristiche del fondale dell’area oggetto di studio. Tre principali ordini di barre sono stati identificati in accordo con gli studi precedenti basati su dati raccolti da indagini in situ e la loro migrazione è stata correlata con il clima ondoso. Durante il periodo analizzato, è stata riscontrata una generale stabilità del sistema di barre in risposta a eventi di tempesta con onde provenienti da NNE, mentre è stato osservato un netto movimento delle barre verso il largo durante l’unica tempesta con onde provenienti da ESE. Il diverso comportamento è stato collegato alla diversa orientazione delle onde e alla riflessione delle onde provenienti da ESE dal molo del fiume.The present thesis concerns the application of the data coming from a new video-monitoring station, called SGS, to improve knowledge of the hydro-morphodynamic processes on a typical natural sandy beach near an estuary along the Adriatic coast (Italy). The SGS station was installed in the Senigallia harbour and collects ten minutes of full-frame images at 2Hz each hour. In this work, the videos of the period 2015-2017 have been post-processed. The elaborated images have been used to perform two different analyses: 1) the study of the capability of the SGS data to estimate the water depth using cBathy (a widely used algorithm for depth-inversion) and 2) the study of the dynamics of a multiple sandbars system. The results of the first analysis varied in quality as a function of the location and wave conditions and a general underestimation of the depth has been found in a large portion of the domain. A detailed debugging analysis was carried out to find the reasons of this poor performance. The main source of error was found to be the large angle between the camera viewing direction and the direction of propagation of the incident waves. A synthetic analysis was performed to analyse in depth this aspect. The synthetic procedure can be applied also to design future shore-based video monitoring stations. With reference to the second analysis, the complex 3D-variability (switching and bifurcation) of the multiple sandbars system has been recognized from the images, this highlighting the capability of the SGS station to monitor the seabed features of the study field. Three orders of bars have been identified, in agreement with previous studies based on data collected by in-situ surveys and their motion has been correlated with the wave climate. In the analysed period, a general stability of the bar system in response to storm events with waves coming from NNE has been found, while a net offshore migration has been observed under the only storm with waves coming from ESE. The different behaviour has been related to the wave direction and to the reflection of the ESE waves off the wall of the nearby river pier
Application of hydrokinetic turbines in microtidal rivers: The Misa River test site
Get PDFThe present study focuses on the potential application of Archimedes screw turbines in microtidal rivers. The Misa River, a 48-km long Italian course flowing into the Adriatic Sea, is taken as the reference test. Since hydrokinetic turbines operate with low discharges and require little engineering facilities, an Archimedes turbine was recently tested both in laboratory and numerically, showing performance coefficients up to 23.8%. To investigate its functioning within the Misa River, observed river stages are statistically analyzed and then used at the upstream boundary of a hydraulic model. The flow results are analyzed to evaluate the potential energy production of turbine configurations built upon a range of: (i) potential installation zones along the river, (ii) turbine radii, (iii) streamwise inclinations of the turbine axis. The energetic analysis of each configuration is performed accounting for one or more turbines installed along selected river cross-sections. A direct dependence is found between generated power and turbine size, especially for the inclined configurations. The optimal size and number of devices to be deployed at specific cross-sections are identified. The total annual energy for the best configurations is around 1MWh, which may find application to supply energy to community buildings, like schools or kindergarten
Monitoring for Coastal Resilience: A Project for Five Italian Beaches
No full textThis paper presents the COPEMAP project, fruit of a research collaboration between the Università Politecnica delle Marche and the Istituto Superiore per la Protezione e la Ricerca Ambientale. The project focuses on developing a methodology for the assessment of beach resilience as a function of both natural forcing (e.g. incoming wave fields) and natural protection (e.g. underwater sand bars). This is accomplished through simplified analyses of available video-monitoring data
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
Entomological survey in a LLIN-protected village of Burkina Faso shows unexpectedly low Human Blood Index associated to high Plasmodium sporozoite rates in the malaria vector Anopheles coluzzii
No full textBackground & Objective: Despite the effectiveness of mass distribution of long-lasting insecticidal nets (LLINs) in reducing malaria transmission in the continent of Africa, in hyperendemic countries such as Burkina Faso the burden of malaria remains high.
Materials & Method: We here report the results of a longitudinal survey (August - November 2011) on human blood index (HBI) and Plasmodium sporozoite rate (SR) in malaria vectors from a LLIN-protected village in Burkina Faso one year following a national bednet distribution programme.
Results & Discussion: The HBI was 20.2% and 5.8% in Anopheles coluzzii (N=263) and An. arabiensis (N=103), the two most abundant malaria vectors in the area, respectively. These values are much lower than usually reported for a highly anthropophilic species such as An. coluzzii, consistent with the hypothesis that LLINs reduced the availability of human hosts to mosquitoes, and with the high presence of cattle breeding in the village. Unexpectedly, SR was found to be relatively high (An. coluzzii: 7.6%, N=503; An. arabiensis: 5.3%, N=225) particularly in relation to the low HBI observed. A regression analysis of data from a systematic review of published studies reporting HBI and SR for An. gambiae complex confirms that the observed SR values are out of the expected ranges, reinforcing the hypothesis that in the study site the reduced human/vector contact caused by LLINs was not sufficient to decrease mosquito infection rates.
Conclusion & Recommendation: These results could contribute to the observed partial effectiveness of LLINs in reducing malaria transmission in the region. Moreover, they highlights the need of constant entomological surveys in these areas, in particular to assess the risk levels of outdoor transmission
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
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