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101.
102.
Gianluca Sottili Danilo M. Palladino Biagio Giaccio Paolo Messina 《Mathematical Geosciences》2012,44(5):619-634
Benford’s analysis is applied to the recurrence times of approximately 17,000 seismic events in different geological contexts
of Italy over the last 6 years, including the Mt. Etna volcanic area and the seismic series associated with the destructive
M
w 6.3, 2009 L’Aquila earthquake. A close conformity to Benford’s law and a power-law probability distribution for the recurrence
times of consecutive events is found, as typical of random multiplicative processes. The application of Benford’s law to the
recurrence event times in seismic series of specific seismogenic regions represents a novel approach, which enlarges the occurrence
and relevance of Benford-like asymmetries, with implications on the physics of natural systems approaching a power law behaviour.
Moreover, we propose that the shift from a close conformity of Benford’s law to Brownian dynamics, observed for time separations
among non-consecutive events in the study seismic series, may be ruled by a periodical noise factor, such as the effects of
Earth tides on seismicity tuning. 相似文献
103.
Indoor GNSS signals are typically received with poor signal-to-noise ratio, which impairs the acquisition stage of common
global positioning system (GPS) receivers. Extending the coherent integration time increases the acquisition sensitivity,
but the data-bit-rate limits the maximum achievable performance. Non-coherent processing also improves the detection performance,
but indoor signals require a large amount of accumulations resulting in significant squaring loss. Moreover, both strategies
have high computational complexity which fixes demanding requirements for stand alone mass-market terminals operating in real
time. A sensitivity–complexity trade-off is therefore mandatory. Assisted-GPS, which is included in 3GPP specifications, reduces the overall acquisition complexity and enhances sensitivity. In this paper
we describe a low-complexity-assisted data-wipe-off technique that enables the high-sensitivity acquisition of GPS signals.
The method is based on the acquisition of the strongest signal in order to obtain information that eases the acquisition of
the weaker ones. The analysis also addresses sources of sensitivity loss, such as Doppler effects and local oscillator inaccuracies.
A test campaign with real signals and integration times up to 2 s validates the method, demonstrating the effectiveness of
the proposed technique in indoor environments. 相似文献
104.
Alessandro Pisa Filippo Frontera Gianluca Loffredo Damiano Pellicciotta Natalia Auricchio 《Experimental Astronomy》2005,20(1-3):219-228
We report on preliminary results obtained with a Monte Carlo (MC) code developed to study the optical properties of Laue lenses for astro-physical observations. The MC code is written in the Python programming language and uses open source libraries. Among the physical quantities which can be investigated with the MC code, we paid our attention mainly to the estimation of the effective area, field of view (FOV) and point spread function (PSF) of the lens for observation of sources on-axis and off-axis. 相似文献
105.
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108.
Jochen Woessner Danciu Laurentiu Domenico Giardini Helen Crowley Fabrice Cotton Gottfried Grünthal Gianluca Valensise Ronald Arvidsson Roberto Basili Mine Betül Demircioglu Stefan Hiemer Carlo Meletti Roger W. Musson Andrea N. Rovida Karin Sesetyan Massimiliano Stucchi The SHARE Consortium 《Bulletin of Earthquake Engineering》2015,13(12):3553-3596
109.
Giuseppe Maddaloni Nicola Caterino Gianluca Nestovito Antonio Occhiuzzi 《Bulletin of Earthquake Engineering》2013,11(6):2407-2428
The seismic events occurred in recent years highlighted the extreme vulnerability of large part of the existing constructed facilities and the need to adopt innovative solutions to improve their seismic performance. With this purpose, the possible exploitation of a seismic early warning system (SEWS) in the framework of semi-active structural control using magnetorheological (MR) dampers is herein investigated. The main idea consists in the use of these time-varying properties devices to control an hosting structure by changing their behaviour according to an anticipate estimate, provided by the SEWS, of the peak ground acceleration (PGA) of the incoming earthquake. In this way, the dampers are able to adapt their mechanical characteristics to the specific earthquake obtaining the optimal seismic response. The present paper describes the application of this protection technique to a case-study problem, a highway bridge located in Southern California. The seismic response of the benchmark bridge is investigated by nonlinear time-history analyses by adopting 16 real earthquake ground excitations. These accelerograms cover a wide variety of magnitudes, distances to fault and soil types. Possible errors on estimation of PGA provided by SEWS and their effects on the proposed control system are also considered. The results obtained confirm that unavoidable errors in the PGA estimates provided by the SEWS do not propagate to the seismic response. Conversely, the proposed strategy turns out to damp these errors, resulting in a robust seismic behaviour of the protected structure. 相似文献
110.