1,720,956 research outputs found
Contributions to modeling of Venice coastal peatlands and wetlands
Full text linkThe present Thesis reports an articulated research work that covers several aspects connected with the modeling of subsurface hydrology of organic soils in connection to the main hazards induced by land subsidence of peatlands and the conservation and wise use of wetlands in the Venetian area.
The dynamics of peatland surface deformation both at long and short time scale is studied and a novel two-step modeling approach is proposed to separate the reversible and irreversible components of the land surface displacement.
An empirical relationship is calibrated on the estimated irreversible component of the ground displacements recorded in a 4-year long experimental study in a field site located in the Zennare Basin,Italy. The expected evolution of the Venetian peatland over the present century is then investigated.
The study of the hydrology of organic soils is then focused on the hysteretical behavior of the moisture retention curve measured in the peat soils of the Zennare Basin. The results of the application of a modeling approach that couples an hysteresis model with a relationship that links the soil matrix porosity dynamic to water saturation bring out the importance of including the swelling/shrinkage phenomenon in the description and prediction of water flow into organic soils.
In the last part of the Thesis the focus is shifted to the hydrological dynamics of salt marshes, delicate intertidal zones characterized by a strong hydrological connection between the atmosphere and the subsurface mainly in terms of air fluxes. A two-phase flow model is developed in order to investigate the effects of air flow in the wetlands dynamics. A pressure-based formulation is chosen to allow for natural treatment of the complex and nonlinear boundary conditions to be imposed at the soil-atmosphere interface to take into account the interplay between evapo-transpiration during emersion periods and tidal fluctuations during soil submersion. The results of the application of the model to some test cases aimed at verifying the effect of the inclusion of the air dynamics in the simulation of the water flow in the vadose zone are presented.La presente Tesi riferisce di un articolato lavoro di ricerca che ha coperto diversi aspetti connessi con la modellazione dei processi idrologici sotterranei nei suoli organici in relazione ai principali rischi indotti dalla subsidenza delle aree torbose e alla conservazione e all’uso consapevole delle aree umide nel comprensorio lagunare veneziano.
Sono state analizzate le dinamiche delle deformazioni dei terreni torbosi sia su lunga che su breve scala temporale e si propone un approccio modellistico in due step finalizzato alla separazione dei contributi reversibile e irreversibile della dello spostamento della superficie.
Una relazione empirica per la stima degli spostamenti indotti dalla bio-ossidazione della matrice organica è stata quindi calibrata a partire dalla stimata determinata porzione irreversibile degli spostamenti registrati nell’ambito di una campagna sperimentale di 4 anni nel Bacino Zennare, Italia,
Si è infine investigato l’evoluzione attesa delle zone torbose nell’area di Venezia nel secolo in corso.
Lo studio dell’idrologia dei suoli organici è proseguito con l’analisi del comportamento isteretico della curva di ritenzione capillare misurata nei suoli del Bacino Zennare. I risultati dell’applicazione di un modello che accoppia un modello di isteresi con una relazione empirica che lega la variazione di porosità della matrice solida al grado di saturazione in acqua hanno messo in luce l’importanza delle deformazioni reversibili nella definizione delle curve di risalita capillare nei suoli organici.
L’ultima parte è focalizzata sulle dinamiche idrologiche delle zone barenali, delicate aree intertidali caratterizzate da un forte feedback tra l’atmosfera e il sottosuolo, principalmente in termini di flussi d’aria. Si è sviluppato un modello bifase al fine di approfondire gli effetti del flusso d’aria nelle dinamiche sotterranee. È stato adottata una formulazione alle pressioni che consente il trattamento naturale delle complesse condizioni al contorno non lineari sull’interfaccio suolo/atmosfera al fine di includere gli effetti di evapotraspirazione durante i periodi di emersione e le fluttuazioni mareali in quelle di sommersione della superficie barenale. I risultati dell’applicazione del modello ad alcuni casi test finalizzati al verificare l’importanza di considerare il flusso d’aria nella descrizione del flusso idrico nella zona insatura sono infine proposti
Efficient coupling between a turbulent flow and mobile bed by means of the level-set method and immersed boundaries
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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
CoCAI: Copula-Based Conformal Anomaly Identification for Multivariate Time-Series
No full textWe propose a novel framework that harnesses the power of generative artificial intelligence and copula-based modeling to address two critical challenges in multivariate time-series analysis: delivering accurate predictions and enabling robust anomaly detection. Our method, Copula-based Conformal Anomaly Identification for Multivariate Time-Series (CoCAI), leverages a diffusion-based model to capture complex dependencies within the data, enabling high quality forecasting. The model’s outputs are further calibrated using a conformal prediction technique, yielding predictive regions which are statistically valid, i.e., cover the true target values with a desired confidence level. Starting from these calibrated forecasts, robust outlier detection is performed by combining dimensionality reduction techniques with copula-based modeling, providing a statistically grounded anomaly score. CoCAI benefits from an offline calibration phase that allows for minimal overhead during deployment and delivers actionable results rooted in established theoretical foundations. Empirical tests conducted on real operational data derived from water distribution and sewerage systems confirm CoCAI’s effectiveness in accurately forecasting target sequences of data and in identifying anomalous segments within them
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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