2,697 research outputs found
Eight-potential-well order-disorder ferroelectric model and effects of random fields
An eight-potential-well order-disorder ferroelectric model was presented and
the phase transition was studied under the mean-field approximation. It was
shown that the two-body interactions are able to account for the first-order
and the second order phase transitions. With increasing the random fields in
the system, a first-order phase transition is transformed into a second-order
phase transition, and furthermore, a second-order phase transition is
inhibited.
However, proper random fields can promote the spontaneous appearance of a
first-order phase transition by increasing the overcooled temperature. The
connections of the model with relaxors were discussed.Comment: 8 pages, 5 figures. Submitted to Applied Physics Letter
Automatic fall incident detection in compressed video for intelligent homecare
[[abstract]]This paper presents a compressed-domain fall incident detection scheme for intelligent homecare applications. First, a compressed-domain object segmentation scheme is performed to extract moving objects based on global motion estimation and local motion clustering. After detecting the moving objects, three compressed-domain features of each object are then extracted for identifying and locating fall incidents. The proposed system can differentiate fall-down from squatting by taking into account the event duration. Our experiments show that the proposed method can correctly detect fall incidents in real time.[[fileno]]2030144030047[[department]]電機工程å¸
Anonymizing Periodical Releases of SRS Data by Fusing Differential Privacy
Spontaneous reporting systems (SRS) have been developed to collect adverse
event records that contain personal demographics and sensitive information like
drug indications and adverse reactions. The release of SRS data may disclose
the privacy of the data provider. Unlike other microdata, very few
anonymyization methods have been proposed to protect individual privacy while
publishing SRS data. MS(k, {\theta}*)-bounding is the first privacy model for
SRS data that considers multiple individual records, mutli-valued sensitive
attributes, and rare events. PPMS(k, {\theta}*)-bounding then is proposed for
solving cross-release attacks caused by the follow-up cases in the periodical
SRS releasing scenario. A recent trend of microdata anonymization combines the
traditional syntactic model and differential privacy, fusing the advantages of
both models to yield a better privacy protection method. This paper proposes
the PPMS-DP(k, {\theta}*, {\epsilon}) framework, an enhancement of PPMS(k,
{\theta}*)-bounding that embraces differential privacy to improve privacy
protection of periodically released SRS data. We propose two anonymization
algorithms conforming to the PPMS-DP(k, {\theta}*, {\epsilon}) framework,
PPMS-DPnum and PPMS-DPall. Experimental results on the FAERS datasets show that
both PPMS-DPnum and PPMS-DPall provide significantly better privacy protection
than PPMS-(k, {\theta}*)-bounding without sacrificing data distortion and data
utility.Comment: 10 pages, 11 figure
Determination of the superconducting gap in near optimally doped Bi_2Sr_{2-x}La_xCuO_{6+\delta} (x ~ 0.4) from low-temperature specific heat
Low-temperature specific heat of the monolayer high-Tc superconductor
Bi_2Sr_{2-x}La_xCuO_{6+\delta} has been measured close to the optimal doping
point (x ~ 0.4) in different magnetic fields. The identification of both a T^2
term in zero field and a \sqrt{H} dependence of the specific heat in fields is
shown to follow the theoretical prediction for d-wave pairing, which enables us
to extract the slope of the superconducting gap in the vicinity of the nodes
(v_{\Delta}, which is proportional to the superconducting gap \Delta_0 at the
antinodes according to the standard d_{x^2-y^2} gap function). The v_{\Delta}
or \Delta_0 (~ 12 meV) determined from this bulk measurement shows close
agreement with that obtained from spectroscopy or tunneling measurements, which
confirms the simple d-wave form of the superconducting gap.Comment: 5 pages, 4 figures, 1 tabl
The scorpions of Hainan Island, China (Arachnida: Scorpiones)
The redescriptions and illustrations of three species, Isometrus (Isometrus) maculatus (DeGeer, 1778), Lychas mucronatus (Fabricius, 1798) (Buthidae), and Liocheles australasiae (Fabricius, 1775) (Hemiscorpiidae) from Hainan Island, China are presented. Distribution data and updated key of Hainan scorpions are provided
Effect of magnetic field on the spin resonance in FeTe(0.5)Se(0.5) as seen via inelastic neutron scattering
Inelastic neutron scattering and susceptibility measurements have been
performed on the optimally-doped Fe-based superconductor FeTe(0.5)Se(0.5),
which has a critical temperature, Tc of 14 K. The magnetic scattering at the
stripe antiferromagnetic wave-vector Q = (0.5,0.5) exhibits a "resonance" at ~
6 meV, where the scattering intensity increases abruptly when cooled below Tc.
In a 7-T magnetic field parallel to the a-b plane, Tc is slightly reduced to ~
12 K, based on susceptibility measurements. The resonance in the neutron
scattering measurements is also affected by the field. The resonance intensity
under field cooling starts to rise at a lower temperature ~ 12 K, and the low
temperature intensity is also reduced from the zero-field value. Our results
provide clear evidence for the intimate relationship between superconductivity
and the resonance measured in magnetic excitations of Fe-based superconductors.Comment: 4 pages, 3 figure
Short-range incommensurate magnetic order near the superconducting phase boundary in Fe(1+d)Te(1-x)Se(x)
We performed elastic neutron scattering and magnetization measurements on
Fe(1.07)Te(0.75)Se(0.25) and FeTe(0.7)Se(0.3). Short-range incommensurate
magnetic order is observed in both samples. In the former sample with higher Fe
content, a broad magnetic peak appears around (0.46,0,0.5) at low temperature,
while in FeTe(0.7)Se(0.3) the broad magnetic peak is found to be closer to the
antiferromagnetic (AFM) wave-vector (0.5,0,0.5). The incommensurate peaks are
only observed on one side of the AFM wave-vector for both samples, which can be
modeled in terms of an imbalance of ferromagnetic/antiferromagnetic
correlations between nearest-neighbor spins. We also find that with higher Se
(and lower Fe) concentration, the magnetic order becomes weaker while the
superconducting temperature and volume increase.Comment: Version as appeared in PR
Weak gravitational lensing by an ESTGB black hole in the presence of a plasma
This paper is devoted to studying the weak-field gravitational lensing
properties of a 4D ESTGB black hole, which is surrounded by the plasma medium.
The effects of the magnetic charges and the three plasma distribution models in
the deflection of light around a 4D ESTGB black hole are investigated in
detail. We find that the uniform plasma leads to a larger deflection of light
rays in comparison with the singular isothermal sphere (SIS), the non-singular
isothermal sphere (NSIS) models. Moreover, the deflection angle increases
slightly as the absolute value of the magnetic charge decreases. Finally, we
analyze the total magnification of image due to weak gravitational lensing
around the black hole. The result shows that the presence of a uniform plasma
medium remarkably enhances the total magnification whereas the non-uniform
plasma reduces the total magnification.Comment: 24 pages, 15 figure
Gray-body factor and absorption of the Dirac field in ESTGB gravity
The gray-body factor and the absorption cross section of the 4D ESTGB gravity
with a mode of nonlinear electrodynamics for the massless Dirac field are
studied in this paper. The magnetic charge value varies between
and as well as the ADM mass is set to , which
corresponds to a non-extreme black hole. The gray-body factor is obtained using
the semi-analytic WKB method after solving the massless Dirac equation. When
the absolute value of magnetic charge is increasing, the gray-body factor
is decreasing. In addition, the partial absorption cross
section and the total absorption cross section are calculated by using the
partial wave method. We find that the maximum value of partial absorption cross
section decreases as increases. And the existence of magnetic charge
causes the diminishing of the total absorption cross section. Finally, we find
that the absorption cross section of the Dirac field is more sensitive to
electric charge than magnetic charge by comparing the absorption cross section
of the Reissner-Nordstrm and ESTGB-NLED black holes.Comment: 11 pages, 7 figure
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