8,197 research outputs found
Gravitational fields with sources, regular black holes, quasiblack holes, and analogue black holes
We discuss recent developments in gravitational fields with sources, regular
black holes, quasiblack holes, and analogue black holes, related to the talks
presented at the corresponding Parallel Session AT3 of the 13th Marcel
Grossmann Meeting.Comment: Report of the Parallel Session AT3 at the Marcel Grossmann Meeting
13, Stockholm 2012, Proceedings of the Conference. 9 page
Transformation, partitioning and flowâdeposit interactions during the run-out of megaflows
Funded by BG Brasil E&P LtdaPeer reviewedPostprin
Testing for entanglement with periodic coarse-graining
Continuous variables systems find valuable applications in quantum
information processing. To deal with an infinite-dimensional Hilbert space, one
in general has to handle large numbers of discretized measurements in tasks
such as entanglement detection. Here we employ the continuous transverse
spatial variables of photon pairs to experimentally demonstrate novel
entanglement criteria based on a periodic structure of coarse-grained
measurements. The periodization of the measurements allows for an efficient
evaluation of entanglement using spatial masks acting as mode analyzers over
the entire transverse field distribution of the photons and without the need to
reconstruct the probability densities of the conjugate continuous variables.
Our experimental results demonstrate the utility of the derived criteria with a
success rate in entanglement detection of relative to studied
cases.Comment: V1: revtex4, 10 pages, 4 figures + supp. material (4 pages, 1 figure)
V2: Substantial revisions implemented both in theory and experimental data
analysi
Using customer lifetime value and neural networks to improve the prediction of bank deposit subscription in telemarketing campaigns
Customer lifetime value (LTV) enables using client characteristics, such as recency, frequency and monetary value, to describe the value of a client through time in terms of profitability. We present the concept of LTV applied to telemarketing for improving the return-on-investment, using a recent (from 2008 to 2013) and real case study of bank campaigns to sell long-term deposits. The goal was to benefit from past contacts history to extract additional knowledge. A total of twelve LTV input variables were tested, under a forward selection method and using a realistic rolling windows scheme, highlighting the validity of five new LTV features. The results achieved by our LTV data-driven approach using neural networks allowed an improvement up to 4 pp in the Lift cumulative curve for targeting the deposit subscribers when compared with a baseline model (with no history data). Explanatory knowledge was also extracted from the proposed model, revealing two highly relevant LTV features, the last result of the previous campaign to sell the same product and the frequency of past client successes. The obtained results are particularly valuable for contact center companies, which can improve predictive performance without even having to ask for more information to the companies they serve.info:eu-repo/semantics/acceptedVersio
Microstructure identification via detrended fluctuation analysis of ultrasound signals
We describe an algorithm for simulating ultrasound propagation in random
one-dimensional media, mimicking different microstructures by choosing physical
properties such as domain sizes and mass densities from probability
distributions. By combining a detrended fluctuation analysis (DFA) of the
simulated ultrasound signals with tools from the pattern-recognition
literature, we build a Gaussian classifier which is able to associate each
ultrasound signal with its corresponding microstructure with a very high
success rate. Furthermore, we also show that DFA data can be used to train a
multilayer perceptron which estimates numerical values of physical properties
associated with distinct microstructures.Comment: Submitted to Phys. Rev.
Acoustic inversion of the cold water filaments off the Southwest coast of Portugal
Cold water filaments have important implications in the biological and chemical exchanges between the coastal and offshore ocean. The Cape SĂŁo Vicente area in the Southwest coast of Portugal is a well know region where such phenomenon is observed. In October 2004, the multidisciplinary project ATOMS, involving oceanographers and acousticians, was conducted with the objective to complement the sea surface temperature (SST) satellite observation with a full water column characterization. Due to weather and technical conditions during the project sea trial, only CTD measurements in upper layers of the water column were performed. These at sea collected data together with archival data from the NODC database, allowed to establish realistic scenario of the 3D temperature distribution in the area, including deeper water layers. Archival data of temperature profiles suggest the occurrence of other important oceanic phenomena such as the subduction of warm Mediterrenean water, that should also influence the acoustic propagation. With the
help of forward acoustic modelling the significance and signature of the individual oceanographic phenomena on the acoustic
propagation, regarding different sampling strategies of the area by acoustic means is investigated. These investigations allowed to
develop strategies to settle the main problem addressed by this work: invert the cold water filament structure by acoustic means in a complex environment where acoustic propagation is affected also by other important oceanic and bathymetric features. Since, the objective of this work, is to evaluate the ability to perform a 3D characterization of vertical structure of the ocean, a minimal transmit-receive acquisition composed of a suspended source
from a ship and a drifting vertical array, is assumed. The spatial structure is obtained by a combination of inversions
for âmeanâ sound speed/temperature perturbations obtained for source-array cross-sections covering the area of interest.
Matched-field and ray tracing based tomography techniques are used in the inversion for the âmeanâ perturbations. The planned sampling strategies and necessary acoustic equipment to resolve such oceanic features is discussed having in mind future sea trials.ATOMS -
POCTI/MAR/15296/1999; FCT Program POSI - QCA III
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