101,650 research outputs found
SPLODE: Semi-Probabilistic Point and Line Odometry with Depth Estimation from RGB-D Camera Motion
Active depth cameras suffer from several limitations, which cause incomplete
and noisy depth maps, and may consequently affect the performance of RGB-D
Odometry. To address this issue, this paper presents a visual odometry method
based on point and line features that leverages both measurements from a depth
sensor and depth estimates from camera motion. Depth estimates are generated
continuously by a probabilistic depth estimation framework for both types of
features to compensate for the lack of depth measurements and inaccurate
feature depth associations. The framework models explicitly the uncertainty of
triangulating depth from both point and line observations to validate and
obtain precise estimates. Furthermore, depth measurements are exploited by
propagating them through a depth map registration module and using a
frame-to-frame motion estimation method that considers 3D-to-2D and 2D-to-3D
reprojection errors, independently. Results on RGB-D sequences captured on
large indoor and outdoor scenes, where depth sensor limitations are critical,
show that the combination of depth measurements and estimates through our
approach is able to overcome the absence and inaccuracy of depth measurements.Comment: IROS 201
Probabilistic teleportation of unknown two-particle state via POVM
We propose a scheme for probabilistic teleportation of unknown two-particle
state with partly entangled four-particle state via POVM. In this scheme the
teleportation of unknown two-particle state can be realized with certain
probability by performing two Bell state measurements, a proper POVM and a
unitary transformation.Comment: 5 pages, no figur
Consistency of shared reference frames should be reexamined
In a recent Letter [G. Chiribella et al., Phys. Rev. Lett. 98, 120501
(2007)], four protocols were proposed to secretly transmit a reference frame.
Here We point out that in these protocols an eavesdropper can change the
transmitted reference frame without being detected, which means the consistency
of the shared reference frames should be reexamined. The way to check the above
consistency is discussed. It is shown that this problem is quite different from
that in previous protocols of quantum cryptography.Comment: 3 pages, 1 figure, comments are welcom
Searching for high- isomers in the proton-rich mass region
Configuration-constrained potential-energy-surface calculations have been
performed to investigate the isomerism in the proton-rich mass
region. An abundance of high- states are predicted. These high- states
arise from two and four-quasi-particle excitations, with and
, respectively. Their excitation energies are comparatively
low, making them good candidates for long-lived isomers. Since most nuclei
under studies are prolate spheroids in their ground states, the oblate shapes
of the predicted high- states may indicate a combination of isomerism
and shape isomerism
Optimal Controlled Teleportation
We give the analytic expressions of maximal probabilities of successfully
controlled teleportating an unknown qubit via every kind of tripartite states.
Besides, another kind of localizable entanglement is also determined.
Furthermore, we give the sufficient and necessary condition that a three-qubit
state can be collapsed to an EPR pair by a measurement on one qubit, and
characterize the three-qubit states that can be used as quantum channel for
controlled teleporting a qubit of unknown information with unit probability and
with unit fidelity.Comment: 4 page
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Performance of bolted steel-beam to CFST-column joints using stiffened angles in column-removal scenario
This paper presents three experimental investigations on the performance of steel-beam to CFST-column joints using stiffened angle, long bolts and fin plate under a middle column removal scenario. Three specimens were designed and tested. The failure modes and catenary action are investigated in detail. The test results show that increasing the angle plate thickness at the joint could not only improve its performance significantly, but also trigger an early formation of catenary action. Increasing the length of short-limb had influence on the deformation ability of the proposed joint, rather than the load capacity. The buckling of stiffeners could prevent the brittle failure of the joints. With the contribution of catenary action, the joint shows much higher rotation capacities than that required in DoD design guidance. The initial stiffness of the joint was calculated using an analytical model with consideration of bolt pretension. Good agreement to the test results is achieved. A numerical analysis is also carried out, whose results show that adding additional row of bolts would improve the redundancy of the joint under column loss. An equivalent dynamic response evaluation of the joints was also performed. The results show that dynamic amplification coefficient should be worked out considering catenary action under large deformation
The surface and inner temperatures of magnetars
Assuming that the timescale of the magnetic field decay is approximately
equal to that of the stellar cooling via neutrino emission, we obtain a
one-to-one relationship between the effective surface thermal temperature and
the inner temperature. The ratio of the effective neutrino luminosity to the
effective X-ray luminosity decreases with decaying magnetic field.Comment: 3 Pages, 3 Figures, Published in IAU Symposium, 2013, V.291
p.386-388. 2013IAU Symposiu
Analytic description of atomic interaction at ultracold temperatures II: Scattering around a magnetic Feshbach resonance
Starting from a multichannel quantum-defect theory, we derive analytic
descriptions of a magnetic Feshbach resonance in an arbitrary partial wave ,
and the atomic interactions around it. An analytic formula, applicable to both
broad and narrow resonances of arbitrary , is presented for ultracold atomic
scattering around a Feshbach resonance. Other related issues addressed include
(a) the parametrization of a magnetic Feshbach resonance of arbitrary , (b)
rigorous definitions of "broad" and "narrow" resonances of arbitrary and
their different scattering characteristics, and (c) the tuning of the effective
range and the generalized effective range by a magnetic field.Comment: 13 pages, 4 figure
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