1,108 research outputs found
Perfect Information vs Random Investigation: Safety Guidelines for a Consumer in the Jungle of Product Differentiation
We present a graph-theoretic model of consumer choice, where final decisions
are shown to be influenced by information and knowledge, in the form of
individual awareness, discriminating ability, and perception of market
structure. Building upon the distance-based Hotelling's differentiation idea,
we describe the behavioral experience of several prototypes of consumers, who
walk a hypothetical cognitive path in an attempt to maximize their
satisfaction. Our simulations show that even consumers endowed with a small
amount of information and knowledge may reach a very high level of utility. On
the other hand, complete ignorance negatively affects the whole consumption
process. In addition, rather unexpectedly, a random walk on the graph reveals
to be a winning strategy, below a minimal threshold of information and
knowledge.Comment: 27 pages, 12 figure
Anatomy of the quantum melting of the two dimensional Wigner crystal
The Fermi liquid-Wigner crystal transition in a two dimensional electronic
system is revisited with a focus on the nature of the fixed node approximation
done in quantum Monte Carlo calculations. Recently, we proposed (Phys. Rev.
Lett. 94, 046801 (2005)) that for intermediate densities, a hybrid phase (with
the symmetry of the crystal but otherwise liquid like properties) is more
stable than both the liquid and the crystal phase. Here we confirm this result
both in the thermodynamic and continuum limit. The liquid-hybrid transition
takes place at rs=31.5 +/- 0.5. We find that the stability of the hybrid phase
with respect to the crystal one is tightly linked to its delocalized nature. We
discuss the implications of our results for various transition scenarii
(quantum hexatic phase, supersolid, multiple exchange, microemulsions) proposed
in the literature.Comment: 14 pages, 16 figure
Riprogettazione e ristrutturazione della stazione video di Stromboli e nuovo sistema di acquisizione e trasferimento immagini da Vulcano
La sorveglianza visiva dei vulcani attivi siciliani è una delle attività dell’unità funzionale monitoraggio Sistema Poseidon dell’INGV di Catania e consiste nel monitoraggio video continuo di detti vulcani mediante stazioni permanenti.
In questo lavoro è stata rappresentata l’opera di riprogettazione e ristrutturazione della stazione video di Stromboli posta in località “Il Pizzo Sopra la Fossa” in cima al vulcano Stromboli. Tale ristrutturazione è stata necessaria poiché il materiale della stazione video, ormai obsoleto e mal funzionante, non garantiva un servizio continuo, affidabile e qualitativamente accettabile.
Contemporaneamente è stato progettato e messo in opera al Centro Marcello Carapezza di Vulcano un nuovo sistema automatico di acquisizione, digitalizzazione, salvataggio su memoria di massa e trasferimento in internet ed in intranet delle immagini dei vulcani Stromboli e Vulcano. Ciò è stato effettuato utilizzando un software appositamente realizzato ed una linea trasmissione dati dedicata che hanno permesso di superare i continui inconvenienti nel trasferimento di tali immagini da Lipari
Collective Charge Fluctuations in Single-Electron Processes on Nano-Networks
Using numerical modeling we study emergence of structure and
structure-related nonlinear conduction properties in the self-assembled
nanoparticle films. Particularly, we show how different nanoparticle networks
emerge within assembly processes with molecular bio-recognition binding. We
then simulate the charge transport under voltage bias via single-electron
tunnelings through the junctions between nanoparticles on such type of
networks. We show how the regular nanoparticle array and topologically
inhomogeneous nanonetworks affect the charge transport. We find long-range
correlations in the time series of charge fluctuation at individual
nanoparticles and of flow along the junctions within the network. These
correlations explain the occurrence of a large nonlinearity in the simulated
and experimentally measured current-voltage characteristics and non-Gaussian
fluctuations of the current at the electrode.Comment: 10 pages, 7 figure
The Gamma--Ray Burst catalog obtained with the Gamma Ray Burst Monitor aboard BeppoSAX
We report on the catalog of Gamma--Ray Bursts (GRBs) detected with the Gamma
Ray Burst Monitor aboard the BeppoSAX satellite. It includes 1082 GRBs with
40--700 keV fluences in the range from to erg cm, and with 40--700 keV peak fluxes from to erg cms. We report in the catalog
some relevant parameters of each GRB and discuss the derived statistical
properties.Comment: 48 pages, 14 figures, 4 Tables. Accepted for publication in The
Astrophysical Journal Supplemen
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