1,187 research outputs found
Genome-wide Identification, Characterization, and Expression Analysis of PHT1 Phosphate Transporters in Wheat
Efficient Approximation of the Labeled Multi-Bernoulli Filter for Online Multitarget Tracking
Online tracking time-varying number of targets is a challenging issue due to measurement noise, target birth or death, and association uncertainty, especially when target number is large. In this paper, we propose an efficient approximation of the Labeled Multi-Bernoulli (LMB) filter to perform online multitarget state estimation and track maintenance efficiently. On the basis of the original LMB filer, we propose a target posterior approximation technique to use a weighted single Gaussian component representing each individual target. Moreover, we present the Gaussian mixture implementation of the proposed efficient approximation of the LMB filter under linear, Gaussian assumptions on the target dynamic model and measurement model. Numerical results verify that our proposed efficient approximation of the LMB filer achieves accurate tracking performance and runs several times faster than the original LMB filer
Distributed Multiagent Control Approach for Multitarget Tracking
In multiagent systems, tracking multiple targets is challenging for two reasons: firstly, it is nontrivial to dynamically deploy networked agents of different types for utility optimization; secondly, information fusion for multitarget tracking is difficult in the presence of uncertainties, such as data association, noise, and clutter. In this paper, we present a novel control approach in distributed manner for multitarget tracking. The control problem is modelled as a partially observed Markov decision process, which is a NP-hard combinatorial optimization problem, by seeking all possible combinations of control commands. To solve this problem efficiently, we assume that the measurement of each agent is independent of other agents’ behavior and provide a suboptimal multiagent control solution by maximizing the local Rényi divergence. In addition, we also provide the SMC implementation of the sequential multi-Bernoulli filter so that each agent can utilize the measurements from neighbouring agents to perform information fusion for accurate multitarget tracking. Numerical studies validate the effectiveness and efficiency of our multiagent control approach for multitarget tracking
Atomic oxygen adsorption and incipient oxidation of the Pb(111) surface: A density-functional theory study
We study the atomic oxygen adsorption on Pb(111) surface by using
density-functional theory within the generalized gradient approximation and a
supercell approach. The atomic and energetic properties of purely on-surface
and subsurface oxygen structures at the Pb(111) surface are systematically
investigated for a wide range of coverages and adsorption sites. The fcc and
tetra-II sites (see the text for definition) are found to be energetically
preferred for the on-surface and subsurface adsorption, respectively, in the
whole range of coverage considered. The on-surface and subsurface oxygen
binding energies monotonically increase with the coverage, and the latter is
always higher than the former, thus indicating the tendency to the formation of
oxygen islands (clusters) and the higher stability of subsurface adsorption.
The on-surface and subsurface diffusion-path energetics of atomic oxygen, and
the activation barriers for the O penetration from the on-surface to the
subsurface sites are presented at low and high coverages. In particular, it is
shown that the penetration barrier from the on-surface hcp to the subsurface
tetra-I site is as small as 65 meV at low coverage (=0.25). The other
properties of the O/Pb(111) system, including the charge distribution, the
lattice relaxation, the work function, and the electronic density of states,
are also studied and discussed in detail, which consistently show the gradually
stabilizing ionic O-Pb bond with increase of the oxygen coverage.Comment: 31 pages, 16 figure
Suppression of Superconductivity by Twin Boundaries in FeSe
Low-temperature scanning tunneling microscopy and spectroscopy are employed
to investigate twin boundaries in stoichiometric FeSe films grown by molecular
beam epitaxy. Twin boundaries can be unambiguously identified by imaging the
90{\deg} change in the orientation of local electronic dimers from Fe site
impurities on either side. Twin boundaries run at approximately 45{\deg} to the
Fe-Fe bond directions, and noticeably suppress the superconducting gap, in
contrast with the recent experimental and theoretical findings in other iron
pnictides. Furthermore, vortices appear to accumulate on twin boundaries,
consistent with the degraded superconductivity there. The variation in
superconductivity is likely caused by the increased Se height in the vicinity
of twin boundaries, providing the first local evidence for the importance of
this height to the mechanism of superconductivity.Comment: 6 pages, 7 figure
Poly[(aquacalcium)-μ4-pyrazine-2,3-dicarboxylato]
The polymeric title compound, [Ca(C6H2N2O4)(H2O)]n, was synthesized from pyrazine-2,3-dicarboxylic acid and calcium dichloride under hydrothermal conditions. The Ca2+ cation is seven-coordinated by five O atoms and one N atom of four pyrazine-2,3-dicarboxylate anions, and one water molecule. The complete deprotonated pyrazine-2,3-dicarboxylate anion adopts a μ4-coordination mode, resulting in the formation of a three-dimensional structure
Magnon-bandgap controllable artificial domain wall waveguide
In this paper, a magnon-bandgap controllable artificial domain wall waveguide
is proposed by means of micromagnetic simulation. By the investigation of the
propagation behavior and dispersion relationship of spin waves in artificial
domain wall waveguides, it is found that the nonreciprocal propagation of spin
waves in the artificial domain walls are mainly affected by the local effective
exchange field, and the magnon bandgap can be controlled by changing the
maximum value of the effective exchange field. In addition, it is observed that
the artificial domain wall waveguides are structurally more stable than the
natural domain wall waveguides under the same spin wave injection conditions,
and the magnon bandgap of the artificial domain wall waveguides can be adjusted
by its width and magnetic anisotropy parameters. The bandgap controllable
artificial domain wall scheme is beneficial to the miniaturization and
integration of magnon devices and can be applied to future magnonic technology
as a novel frequency filter
Cicatricial Alopecia
Cicatricial alopecia represents a group of disorders sharing a final pathway of destruction followed by replacement with fibrous tissue of the hair follicle unit. Cicatricial alopecia is classified into two categories, namely primary cicatricial alopecia, in which the hair follicle is the sole target of a progressive inflammatory process in a group of diverse skin or systemic diseases, and secondary cicatricial alopecia, referring to the hair follicle destruction as a result of a nonspecific disruption of the dermis. Permanent hair loss may also occur in the late phases of some nonscarring alopecias that are called “biphasic alopecias.” Based on the pathological characteristics, the lesions of primary cicatricial alopecia are divided into lymphocyte-predominant subgroup, neutrophil-predominant subgroup, or mixed subgroup. In principle, the primary goal of the treatment aims to attenuate the progression of the inflammatory and the scarring processes at the earliest phase of the disease. In clinical practice, the lymphocyte-predominant lesions are treated with immunosuppressive agents, whereas the neutrophil-predominant lesions are treated with antimicrobials or dapsone. As the efficacy of medication treatment against the cicatricial alopecia varies significantly, autologous hair transplantation is recommended to patients who have a relatively stable primary or a secondary cicatricial alopecia
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