361 research outputs found
Benchmark on the numerical simulations of the hydrodynamic and morphodynamic evolution of tidal channels and tidal inlets
No full textA correct understanding of the hydrodynamics and morphodynamics of tidal basins is of fundamental
importance for the fate of the Venice Lagoon, Italy. If on one hand, the development of sophisticated
numerical models is called for in order to reproduce the complexity of the mechanisms governing the
morphodynamic evolution of many natural environments, including lagoons, on the other hand, a clear
knowledge of the reliability and limits of the results provided by these models is crucial in order to
establish the condition under which they can be safely applied. To this aim, researchers involved in
numerical modeling in the framework of the recent Corila research programmes, agreed to perform an
accurate comparison of results provided by three different numerical models, applying them to the test
case offered by the experimental investigations performed under controlled conditions by Tambroni
et al. (2005a). Here, we consider the following numerical models: (i) a 2D finite element hydrodynamic
model coupled with a 2D finite volume morphodynamic model (Defina, 2000; Canestrelli et al., 2007);
(ii) a 2D finite element morphodynamic model (Ferrarin et al., 2008); (iii) a 2D depth-averaged model
for the inlet region, coupled with a 1D model for the channel (Tambroni et al., 2005b). A first set of
simulations concerns the fixed bed case and shows that all the models provide similar results: in
particular, they are able to predict the observed free surface oscillations satisfactorily, while comparison
with the measured velocity field is less satisfactory. Moreover, as far as the flow field at the inlet is
concerned, the models describe accurately the potential flow into the channel during the flood phase,
while they are not able to adequately reproduce the occurrence of the fine structure of the shear layers
shed by the inlet edges during the ebb phase. This limit is related to the shallow water character of the
models. As for the morphodynamics, the long term equilibrium configurations of the bottom of the
channel and of the near inlet region show qualitative agreement with the experimental observations,
although in this case the differences between the results provided by the distinct numerical approaches
are more marked
A New Translation of Canestrelli\u27s \u3cem\u3eA Kootenai Grammar\u3c/em\u3e
No full textPhilip Canestrelli\u27s grammar of Kutenai (a language indigenous to northern Idaho), A Kootenai Grammar, was originally published in Latin in 1894. The grammar\u27s few English translations have not been linguistically informed, which has rendered the grammar, the earliest documentation of Kutenai, unavailable for revitalization efforts. To make Canestrelli\u27s work accessible to English speakers, I am referencing multiple editions of the grammar, a partial translation, and modern linguistic work on Kutenai to produce an English translation that is true to Canestrelli\u27s original meaning but still useful for modern linguists.
A Kootenai Grammar contains 144 pages. To date I have completed translation of approximately 40 pages. I am supplementing the English translation with notes that compare Canestrelli\u27s analysis of Kutenai, which is based on Latin grammatical categories, to modern analyses of Kutenai. These annotations include notes on Canestrelli\u27s interpretation of various proximate and obviative morphemes—key features in the grammar of Kutenai. The translation and annotations I provide are equally informed by knowledge of Latin and modern linguistics so that A Kootenai Grammar, a key part of the documentation of the Kutenai language, is accessible in English
Funzioni di penalità esterna in problemi di controllo ottimo quadratico a tempo discreto
No full textIn molti problemi di ottimizzazione a tempo discreto viene costruito un modello dinamico del sistema in termini di variabili di stato e di controllo, in cui le equazioni vettoriali alle differenze finite della dinamica sono lineari e la funzione costo è quadratica sia nelle variabili di stato che di controllo. Esistono numerosi approcci a tale problema non vincolato, il migliore dei quali in presenza di matrici (semi)definite positive si riconduce alla cosidetta equazione di Riccati. Spesso nelle applicazioni economico-finanziarie accade, però, di dover considerare variabili di stato e di controllo soggette a vincoli lineari. Scopo del presente lavoro è illustrare una soluzione del problema che fa uso della equazione di Riccati (per minimizzare la funzione costo) e delle funzioni di penalità esterna (per tener conto dei vincoli)
Un modello di simulazione per il porto di Venezia
No full textQuesto lavoro descrive la metodologia seguita nella stesura di un modello di simulazione relativo al sistema portuale veneziano. Si tratta di uno strumento quantitativo che, prendendo in considerazione alcuni importanti fattori naturali e umani che intervengono nella realtà in esame (numero navi in arrivo, ore di inagibilità per marea o nebbia, efficienza dei servizi di movimentazione navi e merci, disponibilità di accosti, pescaggio dei canali), tenta di leggerne le relazioni fondamentali e di prevedere gli effetti conseguenti a possibili variazioni dello scenario di riferimento, quali, ad esempio, quelle causate dalla progettata chiusura delle bocche di porto allo scopo di salvaguardare Venezia dalle acque alte
Lidar data at Sapelo Island, Georgia, USA
No full textThis is the data corresponding to figure 9 of the paper:
Sergio Fagherazzi, Giulio Mariotti, Nicoletta Leonardi, Alberto Canestrelli, William Nardin, William S. Kearney, Morphodynamics of salt marshes in a period of accelerated sea level rise, Submitted to Journal of Geophysical Research, Centennial Edition.</p
Mettete gli stivali: arriva l'acqua alta
No full textDopo aver brevemente presentato gli effetti dell'acqua alta a Venezia e i relativi mezzi di allertamento, l'articolo elenca e brevemente discute su alcuni modelli, dai più semplici ai più complessi, capaci di fornire buone previsioni sul livello di marea in tempi computazionalmente contenuti
Applications of Multidimensional Stochastic Processes to Financial Investments
No full textIn this paper we study a possible numerical method to reach the solution for a general selevtion model for investments in financial securities whose prices follow an Ito stochastic process. The core of this method is the approximations of the stochastic processes by Markov chains. In these situations, we show some applications to the Italian Stock Exchange Market, in order to verify the practical applicability of the models
A simulation model for water traffic in the historical city centre of Venice
No full textSimulation is a widely used technique to analize and predict the urban traffic. Models for road traffic simulation based on paths between origin/destination pairs have been deeply studied due to the growing importance of transportation planning. Water traffic differ substantially from road traffic for the behaviour of vehicles and needs appropriate models of evaluation. In this work we present a simulation model based on queue networks that has been projected and implemented for Venice historical city
centre
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