2,433 research outputs found
Supervised and Unsupervised Detections for Multiple Object Tracking in Traffic Scenes: A Comparative Study
In this paper, we propose a multiple object tracker, called MF-Tracker, that
integrates multiple classical features (spatial distances and colours) and
modern features (detection labels and re-identification features) in its
tracking framework. Since our tracker can work with detections coming either
from unsupervised and supervised object detectors, we also investigated the
impact of supervised and unsupervised detection inputs in our method and for
tracking road users in general. We also compared our results with existing
methods that were applied on the UA-Detrac and the UrbanTracker datasets.
Results show that our proposed method is performing very well in both datasets
with different inputs (MOTA ranging from 0:3491 to 0:5805 for unsupervised
inputs on the UrbanTracker dataset and an average MOTA of 0:7638 for supervised
inputs on the UA Detrac dataset) under different circumstances. A well-trained
supervised object detector can give better results in challenging scenarios.
However, in simpler scenarios, if good training data is not available,
unsupervised method can perform well and can be a good alternative.Comment: Accepted for ICIAR 202
In vitro responses of dracaena fragrans cv. massangeana to growth regulators
In vitro studies on Dracaena fragrans cv. Massangeana revealed that young stem segments were capable of
proliferating shoots on agar-solidified Murashige and Skoog (MS) basal medium containing different combinations
and concentrations of BAP and NAA. Highest percentage of explants forming shoots was obtained on medium
supplemented with 3.0 mgll BAP and 0.1 mgll NAA. The highest number ofshoots per explant occurred on medium
containing 2.0 mgll BAP only. Highest percentage of callus formation and highest mean fresh weight of callus from
young stem segments were achieved on MS medium supplemented with 1.0 mgll2,4-D. Adventitious rooting occurred
after transferring excised shoots onto a hormone-free MS medium. Rooting was 100% for shoots derived from media
with 0-2.0 mg/l BAP and a relatively low concentration of NAA (0.1 mg/l)
Gravitational radiation from nonaxisymmetric spherical Couette flow in a neutron star
The gravitational wave signal generated by global, nonaxisymmetric shear
flows in a neutron star is calculated numerically by integrating the
incompressible Navier--Stokes equation in a spherical, differentially rotating
shell. At Reynolds numbers \Rey \gsim 3 \times 10^{3}, the laminar Stokes
flow is unstable and helical, oscillating Taylor--G\"ortler vortices develop.
The gravitational wave strain generated by the resulting kinetic-energy
fluctuations is computed in both and polarizations as a function
of time. It is found that the signal-to-noise ratio for a coherent,
-{\rm s} integration with LIGO II scales as for a star at 1 {\rm kpc} with angular velocity
. This should be regarded as a lower limit: it excludes pressure
fluctuations, herringbone flows, Stuart vortices, and fully developed
turbulence (for \Rey \gsim 10^{6}).Comment: (1) School of Physics, University of Melbourne, Parkville, VIC 3010,
Australia. (2) Departamento de Fisica, Escuela de Ciencias,Universidad de
Oriente, Cumana, Venezuela, (3) Department of Mechanical Engineering,
University of Melbourne, Parkville, VIC 3010, Australia. Accepted for
publication in The Astrophysical Journal Letter
Rotational Cooling of Polar Molecules by Stark-tuned Cavity Resonance
A general scheme for rotational cooling of diatomic heteronuclear molecules
is proposed. It uses a superconducting microwave cavity to enhance the
spontaneous decay via Purcell effect. Rotational cooling can be induced by
sequentially tuning each rotational transition to cavity resonance, starting
from the highest transition level to the lowest using an electric field.
Electrostatic multipoles can be used to provide large confinement volume with
essentially homogeneous background electric field.Comment: 10 pages, 6 figure
Global three-dimensional flow of a neutron superfluid in a spherical shell in a neutron star
We integrate for the first time the hydrodynamic
Hall-Vinen-Bekarevich-Khalatnikov equations of motion of a -paired
neutron superfluid in a rotating spherical shell, using a pseudospectral
collocation algorithm coupled with a time-split fractional scheme. Numerical
instabilities are smoothed by spectral filtering. Three numerical experiments
are conducted, with the following results. (i) When the inner and outer spheres
are put into steady differential rotation, the viscous torque exerted on the
spheres oscillates quasiperiodically and persistently (after an initial
transient). The fractional oscillation amplitude () increases
with the angular shear and decreases with the gap width. (ii) When the outer
sphere is accelerated impulsively after an interval of steady differential
rotation, the torque increases suddenly, relaxes exponentially, then oscillates
persistently as in (i). The relaxation time-scale is determined principally by
the angular velocity jump, whereas the oscillation amplitude is determined
principally by the gap width. (iii) When the mutual friction force changes
suddenly from Hall-Vinen to Gorter-Mellink form, as happens when a rectilinear
array of quantized Feynman-Onsager vortices is destabilized by a counterflow to
form a reconnecting vortex tangle, the relaxation time-scale is reduced by a
factor of compared to (ii), and the system reaches a stationary state
where the torque oscillates with fractional amplitude about a
constant mean value. Preliminary scalings are computed for observable
quantities like angular velocity and acceleration as functions of Reynolds
number, angular shear, and gap width. The results are applied to the timing
irregularities (e.g., glitches and timing noise) observed in radio pulsars.Comment: 6 figures, 23 pages. Accepted for publication in Astrophysical
Journa
Controlling laser spectra in a phaseonium photonic crystal using maser
We study the control of quantum resonances in photonic crystals with
electromagnetically induced transparency driven by microwave field. In addition
to the control laser, the intensity and phase of the maser can alter the
transmission and reflection spectra in interesting ways, producing hyperfine
resonances through the combined effects of multiple scattering in the
superstructure.Comment: 7 pages, 4 figure
Vortex Matter Transition in BiSrCaCuO under Tilted Fields
Vortex phase diagram under tilted fields from the axis in
BiSrCaCuO is studied by local magnetization
hysteresis measurements using Hall probes. When the field is applied at large
angles from the axis, an anomaly () other than the well-known
peak effect () are found at fields below . The angular dependence of
the field is nonmonotonic and clearly different from that of
and depends on the oxygen content of the crystal. The results suggest existence
of a vortex matter transition under tilted fields. Possible mechanisms of the
transition are discussed.Comment: Revtex, 4 pages, some corrections are adde
Characterization of a Plain Broadband Textile PIFA
Bandwidth characteristic of a wearable antenna is one of the major factors in determining its usability on the human body. In this work, a planar inverted-F antenna (PIFA) structure is proposed to achieve a large bandwidth to avoid serious antenna reflection coefficient detuning when placed in proximity of the body. The proposed structure is designed based on a simple structure, in order to provide practicality in application and maintain fabrication simplicity. Two different types of conductive textiles, namely Pure Copper Polyester Taffeta Fabric (PCPTF) and ShieldIt, are used in order to proof its concept, in comparison with a metallic antenna made from copper foil. The design is spaced and fabricated using a 6 mm thick fleece fabric. To cater for potential fabrication and material measurement inaccuracies, both antennas' performance are also investigated and analyzed with varying physical and material parameters. From this investigation, it is found that the proposed structure's extended bandwidth enabled the antenna to function with satisfactory on-body reflection coefficients, despite unavoidable gain and efficiency reduction
Hydrogels that listen to cells:a review of cell-responsive strategies in biomaterial design for tissue regeneration
The past decade has seen a decided move from static and passive biomaterials to biodegradable, dynamic, and stimuli responsive materials in the laboratory and the clinic. Recent advances towards the rational design of synthetic cell-responsive hydrogels-biomaterials that respond locally to cells or tissues without the input of an artificial stimulus-have provided new strategies and insights on the use of artificial environments for tissue engineering and regenerative medicine. These materials can often approximate responsive functions of a cell's complex natural extracellular environment, and must respond to the small and specific stimuli provided within the vicinity of a cell or tissue. In the current literature, there are three main cell-based stimuli that can be harnessed to create responsive hydrogels: (1) enzymes (2) mechanical force and (3) metabolites/small molecules. Degradable bonds, dynamic covalent bonds, and non-covalent or supramolecular interactions are used to provide responsive architectures that enable features ranging from cell selective infiltration to control of stem-cell differentiation. The growing ability to spatiotemporally control the behavior of cells and tissue with rationally designed responsive materials has the ability to allow control and autonomy to future generations of materials for tissue regeneration, in addition to providing understanding and mimicry of the dynamic and complex cellular niche
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