5,983 research outputs found
Multi-species mean-field spin-glasses. Rigorous results
We study a multi-species spin glass system where the density of each species
is kept fixed at increasing volumes. The model reduces to the
Sherrington-Kirkpatrick one for the single species case. The existence of the
thermodynamic limit is proved for all densities values under a convexity
condition on the interaction. The thermodynamic properties of the model are
investigated and the annealed, the replica symmetric and the replica symmetry
breaking bounds are proved using Guerra's scheme. The annealed approximation is
proved to be exact under a high temperature condition. We show that the replica
symmetric solution has negative entropy at low temperatures. We study the
properties of a suitably defined replica symmetry breaking solution and we
optimise it within a ziggurat ansatz. The generalized order parameter is
described by a Parisi-like partial differential equation.Comment: 17 pages, to appear in Annales Henri Poincar\`
Evolution and strengthening of the Calabrian Regional Seismic Network
The Calabrian Arc is an area of high seismic hazard,
in the past often affected by destructive earthquakes. The
seismicity of the Calabrian region is monitored by the Italian
National Seismic Network integrated by the Calabrian Regional
one and, in the last three years, by the Pollino temporary
array. We have applied the Seismic Network Evaluation
through Simulation to assess the individual contribution of
each network in locating earthquakes with epicentres in the
Calabrian region and surrounding. We shows that the Calabrian
Regional Seismic Network greatly improves the quality
of the coverage in almost the Calabria territory except in
the Crotone Basin, in the Serre and in the offshore areas. We
show that the contribution of the Pollino temporary array is
instead restricted to a very small area centred on the Pollino
Chain. Due to the presence in the Serre of important seismogenic
volumes, which in the past have generated destructive
earthquakes, it would be opportune to add at least several
seismic stations in this area and surrounding to improve the
seismic monitoring
La rete sismica della Calabria
L’installazione e gestione di una rete di sismografi finalizzata al monitoraggio della sismicità della Calabria risale agli inizi degli anni ‘70, quando furono attribuiti come compiti prima all’IRPI-CNR e quindi al Dipartimento di Scienze della Terra
dell’Università della Calabria (UniCal). Tuttavia le prime stazioni furono attivate solo a partire dal 1978, sostanzialmente nell’ambito del Progetto Finalizzato Geodinamica (PFG). La crescita della
struttura fu rallentata dalla carenza di personale tecnico, problema che tuttora rappresenta una difficoltà e, dopo la chiusura del PFG, anche di risorse finanziarie
About the ergodic regime in the analogical Hopfield neural networks. Moments of the partition function
In this paper we introduce and exploit the real replica approach for a
minimal generalization of the Hopfield model, by assuming the learned patterns
to be distributed accordingly to a standard unit Gaussian. We consider the high
storage case, when the number of patterns is linearly diverging with the number
of neurons. We study the infinite volume behavior of the normalized momenta of
the partition function. We find a region in the parameter space where the free
energy density in the infinite volume limit is self-averaging around its
annealed approximation, as well as the entropy and the internal energy density.
Moreover, we evaluate the corrections to their extensive counterparts with
respect to their annealed expressions. The fluctuations of properly introduced
overlaps, which act as order parameters, are also discussed.Comment: 15 page
Three years of gravity continous obsevations in the Calabria Arc System: a model of the gravity tide and the tidal field
Remarkable mass displacements of different origin and nature are currently active in the
geological domain known as Calabrian-Peloritani Arc and in the adjacent Tyrrhenian and Ionian Seas. Geophysical, geological and archeological evidence exists that the Ionian coasts
are interested by intense subsidence phenomena(e.g. Marino et al., 2010; Minelli et al., 2013; Stanley and Bernasconi, 2012). However, over geological times, the whole Calabrian region has been rapidly rising relatively to the sea level. The region can be subdivided into several blocks that move upwards with different mean vertical velocities, estimated in some areas up to
about 2 mm/yr in the last 700,000 years (e.g. Sorriso-Valvo, 1993; Westaway, 1993; Antonioli al., 2006). Finally, as shown by the intermediate and deep local seismicity the subduction under the Tyrrhenian Sea is still active and should be taken into account, whatever its stage of
development (e.g. Monna et al., 2013; Piana Agostinetti et al., 2009, and reference therein).
Although since over a century the Calabrian region is going through a period of relative seismic quietness, its seismic hazard is at the highest levels in the Mediterranean basin due to several catastrophic earthquakes present in the historical records
Testing M2T/T2M Transformations
Presentado en: 16th International Conference on Model Driven Engineering Languages and Systems (MODELS 2013). Del 29 de septiembre al 4 de octubre. Miami, EEUU.Testing model-to-model (M2M) transformations is becoming a prominent topic in the current Model-driven Engineering landscape. Current approaches for transformation testing, however, assume having explicit model representations for the input domain and for the output domain of the transformation. This excludes other important transformation kinds, such as model-to-text (M2T) and text-to-model (T2M) transformations, from being properly tested since adequate model representations are missing either for the input domain or for the output domain. The contribution of this paper to overcome this gap is extending Tracts, a M2M transformation testing approach, for M2T/T2M transformation testing. The main mechanism we employ for reusing Tracts is to represent text within a generic metamodel. By this, we transform the M2T/T2M transformation specification problems into equivalent M2M transformation specification problems. We demonstrate the applicability of the approach by two examples and present how the approach is implemented for the Eclipse Modeling Framework (EMF). Finally, we apply the approach to evaluate code generation capabilities of several existing UML tools.Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech. Proyecto TIN2011-2379
Continuous gravity and tilt observations in an active geodynamic area of southern Italy: the Calabrian Arc system
Calabria (southern Italy) is a site of considerable seismic activity related to the ongoing evolution of the Calabrian Arc system, where a complex lithospheric structure is present. For over a century the Calabrian region has been going through a period of relative seismic quietness, yet its seismic hazard is at the highest levels in the Mediterranean basin due to several catastrophic earthquakes present in the historical records. In order to strengthen the geophysical monitoring of this region, a gravity and tilt recording station was set up in the premises of the University of Calabria. The recorded signals should allow to estimate a tidal anomaly, possibly correlated with the difference between some local feature of the lithosphere or geodynamic activity and the corresponding characteristics of the model used to calculate the reference gravity tide. We report here on the results obtained by the analysis of more than two years of continuous gravity and tilt observations at a site in the northern part of the region. The tidal analysis of the gravity records, covering the time interval May 2011 - September 2013, has provided amplitudes, amplification factors and phases of the main lunar and solar gravity tidal waves. A reliable model of the gravity tide is necessary for accurate processing of discrete absolute and relative gravimetric
measurements and to detect in the gravity signals possible components correlated to
major seismic activity. The Ocean Tide Load (OTL) effect was accounted for in the
determination of the tidal field spectral parameters. The most widespread DDW99/
NH Earth’s model, adopted here as reference, fits the obtained results well enough.
The tidal residual vectors do not highlight any significant anomaly ascribable to the
complex structure of the lithosphere beneath the region. The analysis of the tilt records
points out a manifest influence of the fluctuations of the air temperature on ground
slope, at annual and diurnal periods. The spectral analysis highlights the presence, on
both E-W and N-S components, of a significant S1 solar wave. Values of the thermal admittance, at diurnal period, have been estimated for both tilt components. A weak energy at the frequency of 1.932 cycles/day, at the limit of statistical significance, is also observed, identifiable as the main semidiurnal lunar wave M2 of the crustal tide. The amplitude and the amplification factors of such a wave are consistent with the values expected by the DDW99/NH model. Beyond everything, the obtained results of the analyses of gravity and tilt records have provided models for the gravity tide and tidal field in the Calabrian region. Moreover, it turns out that the response of the complex lithospheric structure in the Calabrian Arc system to the tidal stress field does not produce any significant anomaly related to the adopted model. Moreover, the absolute measurements of the gravity acceleration, carried out in 1994 and 2013, yielded coinciding values, implying that during the time interval of 20 years not any significant vertical movement and/or mass redistribution in the underground occurred
in the area, despite its intense geodynamic activity
The 1998-1999 Pollino (Southern Apennines, Italy) seismic crisis: tomography of a sequence
In 1998-1999 a seismic sequence occurred in the Southern Apennines, after the moderate size (mb=5.0) 9th September
1998 Pollino earthquake. It lasted about 14 months and was clearly localized to the sole north-west area
of the main shock epicenter. Its peculiarity consisted in sudden changes of activity from a series of normal faults
with Apenninic (NW-SE) trend and transfer, presumably strike slip, faults with Antiapenninic (NE-SW) and E-W
trend. The complexity of the behavior and the different orientations of the activated systems suggest that the area
acts as a hinge between the NW-SE trending Southern Apennines and the locally N-S trending Calabrian Arc
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