8,677 research outputs found
An evaluation of entropy measures for microphone identification
Research findings have shown that microphones can be uniquely identified by audio recordings since physical features of the microphone components leave repeatable and distinguishable traces on the audio stream. This property can be exploited in security applications to perform the identification of a mobile phone through the built-in microphone. The problem is to determine an accurate but also efficient representation of the physical characteristics, which is not known a priori. Usually there is a trade-off between the identification accuracy and the time requested to perform the classification. Various approaches have been used in literature to deal with it, ranging from the application of handcrafted statistical features to the recent application of deep learning techniques. This paper evaluates the application of different entropy measures (Shannon Entropy, Permutation Entropy, Dispersion Entropy, Approximate Entropy, Sample Entropy, and Fuzzy Entropy) and their suitability for microphone classification. The analysis is validated against an experimental dataset of built-in microphones of 34 mobile phones, stimulated by three different audio signals. The findings show that selected entropy measures can provide a very high identification accuracy in comparison to other statistical features and that they can be robust against the presence of noise. This paper performs an extensive analysis based on filter features selection methods to identify the most discriminating entropy measures and the related hyper-parameters (e.g., embedding dimension). Results on the trade-off between accuracy and classification time are also presented
Pressure induced magnetic phase separation in LaCaMnO manganite
The pressure dependence of the Curie temperature T in
LaCaMnO was determined by neutron diffraction up to 8
GPa, and compared with the metallization temperature T \cite{irprl}.
The behavior of the two temperatures appears similar over the whole pressure
range suggesting a key role of magnetic double exchange also in the pressure
regime where the superexchange interaction is dominant. Coexistence of
antiferromagnetic and ferromagnetic peaks at high pressure and low temperature
indicates a phase separated regime which is well reproduced with a dynamical
mean-field calculation for a simplified model. A new P-T phase diagram has been
proposed on the basis of the whole set of experimental data.Comment: 5 pages, 4 figure
Aportación al estudio de prácticas mortuorias durante el Período de Desarrollos Regionales. Entierros en vasijas utilitarias del sector central del valle Calchaquí (Salta, Argentina)
In this paper we analyze published and unpublished information on sub-adults´ burials in urns from settlements of the Regional Development Period (9th - 15th centuries) in central Calchaquí Valley, Salta, Argentina. We deepen into information about late children´ burials in ordinary vessels, the use of certain words and ideas, and about signs related to mortuary practices
On -- the basic ingredients for strangeness production in heavy ion collisions
The strangeness production in heavy ion collisions was proposed to be probes
of the nuclear equation of state, Kaon potential in nuclear medium, strange
quark matter and quark-gluon plasma, etc. However, to act as reliable probes,
proper understanding of the basic ingredients for the strangeness production,
such as , and is
necessary. Recent study of these reactions clearly shows that previously
ignored contributions from the spin-parity resonances, and
, are in fact very important for these reactions, especially
for near-threshold energies. It is necessary to include these contributions for
getting reliable calculation for the strangeness production in heavy ion
collisions.Comment: 12 pages, 12 figures, Contributed to the proceedings of the
International workshop on nuclear dynamics in heavy-ion reactions and neutron
stars, July, 10-14, Beijing, Chin
decay in the isobar resonance model
Based on the effective Lagrangian approach, the
decay is studied in an isobar resonance model with the assumption that the
-meson is produced from intermediate nucleon resonances. The
contributions from the , ,
and states are considered. In terms of
the coupling constants and
extracted from the data of the partial decay widths of the s to the
channel, the reaction cross section of the process
and the partial decay widths of the and
processes, respectively, the invariant mass
spectrum and the Dalitz plot for are predicted. It
is shown that there are two types of results. In the type I case, a large peak
structure around 2.09GeV implies that a considerable mount of or
component may exist in the narrow-width state,
but for the wide-width state, it has little
component. In the type II case, a small peak around 2.11GeV may only indicate
the existence of a certain mount of or component in the
narrow-width state, but no information for the wide-width
state. Further BESIII data with high statistics would help
us to distinguish the strange structures of these s
The role of the N*(1535) resonance and the pi^- p --> KY amplitudes in the OZI forbidden pi N --> phi N reaction
We study the pi N --> phi N reaction close to the phi N threshold within the
chiral unitary approach, by combining the pi^- p --> K^+ Sigma^-, pi^- p -->
K^0 Sigma^0 and pi^- p --> K^0 Lambda amplitudes with the coupling of the phi
to the K components of the final states of these reactions via quantum loops.
We obtain a good agreement with experiment when the dominant pi^- p --> K^0
Lambda amplitude is constrained with its experimental cross section. We also
evaluate the coupling of the N*(1535) to phi N and find a moderate coupling as
a consequence of partial cancellation of the large KY components of the
N*(1535). We also show that the N*(1535) pole approximation is too small to
reproduce the measured cross section for the pi N --> phi N reaction.Comment: 10 pages, 6 figure
Evidence for an Excited Hyperon State in pp -> p K^+ Y^{0*}
Indications for the production of a neutral excited hyperon in the reaction
pp -> p K^+ Y^{0*} are observed in an experiment performed with the ANKE
spectrometer at COSY-J\"ulich at a beam momentum of 3.65 GeV/c. Two final
states were investigated simultaneously, viz. Y^{0*} -> pi^+X^- and pi^-X^+,
and consistent results were obtained in spite of the quite different
experimental conditions. The parameters of the hyperon state are M(Y^{0*})=
(1480 +/- 15) MeV/c^2 and Gamma(Y^{0*})= (60 +/- 15) MeV/c^2. The production
cross section is of the order of few hundred nanobarns. Since the isospin of
the Y^{0*} has not been determined here, it could either be an observation of
the Sigma(1480), a one-star resonance of the PDG tables, or alternatively a
Lambda hyperon. Relativistic quark models for the baryon spectrum do not
predict any excited hyperon in this mass range and so the Y^{0*} may be of
exotic nature.Comment: 4 pages, 3 figures, accepted for publication in Phys.Rev.Let
The role of in and reactions
The near threshold meson production in proton-proton and
collisions is studied with the assumption that the production mechanism is due
to the sub--threshold resonance. The , and
-meson exchanges for proton-proton collisions are considered. It is
shown that the contribution to the reaction from the t-channel
meson exchange is dominant. With a significant
coupling ( = 0.13), both and
data are very well reproduced. The significant coupling of
the resonance to is compatible with previous indications
of a large component in the quark wave function of the
resonance and may be the real origin of the significant enhancement of the
production over the naive OZI-rule predictions.Comment: 15 pages, 6 figure
Aerosol Jet Printing of a Benzocyclobutene-Based Ink as Adhesive Material for Wafer Bonding Application
Aerosol jet printing (AJP) is an emerging additive manufacturing technology that is gaining increasing attention in the electronic field. Several studies have been carried out on the AJP of conductive, semiconductive, and dielectric polymers for electronic applications. However, wafer bonding is an application that is still uncovered by literature. Therefore, in this work, the AJP of benzocyclobutene (BCB) as a polymeric adhesive for wafer bonding is presented for the first time. A thorough characterization of the processing parameters is carried out to identify the most ideal conditions for printing at a relatively high speed. Then, square patterns are printed, proving the versatility of the AJP technology in terms of the reachable thickness of the deposited BCB patterns. Complex patterns with a resolution of approximate to 60 mu m are also printed. The bonding properties of the BCB are characterized from a morphological and mechanical point of view. In particular, the shear strength of the BCB coatings deposited with AJP is approximate to 39 MPa and it is comparable with the shear strength of BCB coating deposited by spin-coating. Consequently, AJP represents a valid alternative for the deposition of polymeric adhesive for wafer bonding
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