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Secondary Microseisms Characterization and Green’s Function Extraction at the Larderello-Travale Geothermal Field (Italy)Zupo, Maria <1983> 30 April 2015 (has links)
Over the past ten years, the cross-correlation of long-time series of ambient
seismic noise (ASN) has been widely adopted to extract the surface-wave
part of the Green’s Functions (GF). This stochastic procedure relies on the
assumption that ASN wave-field is diffuse and stationary. At frequencies <1Hz, the ASN is mainly composed by surface-waves, whose origin is attributed
to the sea-wave climate. Consequently, marked directional properties may be
observed, which call for accurate investigation about location and temporal
evolution of the ASN-sources before attempting any GF retrieval. Within
this general context, this thesis is aimed at a thorough investigation about
feasibility and robustness of the noise-based methods toward the imaging
of complex geological structures at the local (∼10-50km) scale. The study
focused on the analysis of an extended (11 months) seismological data set
collected at the Larderello-Travale geothermal field (Italy), an area for which
the underground geological structures are well-constrained thanks to decades
of geothermal exploration.
Focusing on the secondary microseism band (SM;f>0.1Hz), I first
investigate the spectral features and the kinematic properties of the noise
wavefield using beamforming analysis, highlighting a marked variability with
time and frequency. For the 0.1-0.3Hz frequency band and during Spring-
Summer-time, the SMs waves propagate with high apparent velocities and
from well-defined directions, likely associated with ocean-storms in the south-
ern hemisphere. Conversely, at frequencies >0.3Hz the distribution of back-
azimuths is more scattered, thus indicating that this frequency-band is the
most appropriate for the application of stochastic techniques. For this latter
frequency interval, I tested two correlation-based methods, acting in the time
(NCF) and frequency (modified-SPAC) domains, respectively yielding esti-
mates of the group- and phase-velocity dispersions. Velocity data provided
by the two methods are markedly discordant; comparison with independent
geological and geophysical constraints suggests that NCF results are more
robust and reliable.
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Exploring Quantum Speed-up Through Cluster-state ComputersAnnovi, Filippo <1986> 28 May 2015 (has links)
The aim of this thesis is to investigate the nature of quantum computation and the question of the quantum speed-up over classical computation by comparing two different quantum computational frameworks, the traditional quantum circuit model and the cluster-state quantum computer. After an introductory survey of the theoretical and epistemological questions concerning quantum computation, the first part of this thesis provides a presentation of cluster-state computation suitable for a philosophical audience. In spite of the computational equivalence between the two frameworks, their differences can be considered as structural. Entanglement is shown to play a fundamental role in both quantum circuits and cluster-state computers; this supports, from a new perspective, the argument that entanglement can reasonably explain the quantum speed-up over classical computation. However, quantum circuits and cluster-state computers diverge with regard to one of the explanations of quantum computation that actually accords a central role to entanglement, i.e. the Everett interpretation. It is argued that, while cluster-state quantum computation does not show an Everettian failure in accounting for the computational processes, it threatens that interpretation of being not-explanatory. This analysis presented here should be integrated in a more general work in order to include also further frameworks of quantum computation, e.g. topological quantum computation. However, what is revealed by this work is that the speed-up question does not capture all that is at stake: both quantum circuits and cluster-state computers achieve the speed-up, but the challenges that they posit go besides that specific question. Then, the existence of alternative equivalent quantum computational models suggests that the ultimate question should be moved from the speed-up to a sort of “representation theorem” for quantum computation, to be meant as the general goal of identifying the physical features underlying these alternative frameworks that allow for labelling those frameworks as “quantum computation”.
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Intuizione e visualizzazione in matematica con particolare riferimento a Felix Klein / Intuition and visualization in mathematics with particular reference to Felix KleinMuttini, Daniele <1976> 19 November 2012 (has links)
Questo lavoro trae spunto da un rinnovato interesse per l’«intuizione» e il «pensiero visivo» in matematica, e intende offrire un contributo alla discussione contemporanea su tali questioni attraverso lo studio del caso storico di Felix Klein. Dopo una breve ricognizione di alcuni dei saggi più significativi al riguardo, provenienti sia dalla filosofia della matematica, sia dalla pedagogia, dalle neuroscienze e dalle scienze cognitive, l’attenzione si concentra sulla concezione epistemologia di Klein, con particolare riferimento al suo uso del concetto di ‘intuizione’. Dai suoi lavori e dalla sua riflessione critica si ricavano non solo considerazioni illuminanti sulla fecondità di un approccio «visivo», ma argomenti convincenti a sostegno del ruolo cruciale dell’intuizione in matematica. / Arising from the renewed interest in ‘intuition’ and ‘visual thinking’ in mathematics, this work intends to take part to the contemporary debate on these topics by investigating the ‘historical case’ of Felix Klein. After a brief survey of studies both from philosophy of mathematics and from neuroscience, pedagogy, and cognitive sciences, that have contributed to such revival, the attention is focused on Klein’s epistemological views, with particular reference to his use of the concept of intuition. The analysis aims at clarifying how his reflections provide not only ingenious observations on the effectiveness of a ‘visual’ approach, but also convincing arguments to support the crucial role of intuition in mathematics.
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Studio della deformazione geodetica delle isole Eolie con particolare riferimento al vulcano di PanareaEsposito, Alessandra <1963> 25 June 2007 (has links)
No description available.
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Studio di maremoti prodotti da frane e terremoti mediante simulazioni numerichePagnoni, Gianluca <1975> 25 June 2007 (has links)
No description available.
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Sviluppo di un sistema di monitoraggio sismico da fondale marino: applicazioni all'area vulcanica dei Campi FlegreiVassallo, Maurizio <1975> 23 May 2007 (has links)
No description available.
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L'approccio subcognitivo allo studio della mente: modelli, concetti, analogieBianchini, Francesco <1976> 30 March 2007 (has links)
No description available.
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Contributi sulla teoria delle nozioni comuni in SpinozaCeccarelli, Alessandro <1972> 30 March 2007 (has links)
No description available.
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Da Angelo Clareno a Jan Amos Comenius: fatti e protagonisti del millenarismo boemoComi, Armando <1978> 30 March 2007 (has links)
No description available.
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L'immaginazione, i demoni e il dubbio: demonologia e scetticismo in Pierre Baylede Lorenzis, Tommaso <1976> 30 March 2007 (has links)
No description available.
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