310 research outputs found
MovePose: A High-performance Human Pose Estimation Algorithm on Mobile and Edge Devices
We present MovePose, an optimized lightweight convolutional neural network
designed specifically for real-time body pose estimation on CPU-based mobile
devices. The current solutions do not provide satisfactory accuracy and speed
for human posture estimation, and MovePose addresses this gap. It aims to
maintain real-time performance while improving the accuracy of human posture
estimation for mobile devices. The network produces 17 keypoints for each
individual at a rate exceeding 11 frames per second, making it suitable for
real-time applications such as fitness tracking, sign language interpretation,
and advanced mobile human posture estimation. Our MovePose algorithm has
attained an Mean Average Precision (mAP) score of 67.7 on the COCO
\cite{cocodata} validation dataset. The MovePose algorithm displayed efficiency
with a performance of 69+ frames per second (fps) when run on an Intel
i9-10920x CPU. Additionally, it showcased an increased performance of 452+ fps
on an NVIDIA RTX3090 GPU. On an Android phone equipped with a Snapdragon 8 + 4G
processor, the fps reached above 11. To enhance accuracy, we incorporated three
techniques: deconvolution, large kernel convolution, and coordinate
classification methods. Compared to basic upsampling, deconvolution is
trainable, improves model capacity, and enhances the receptive field. Large
kernel convolution strengthens these properties at a decreased computational
cost. In summary, MovePose provides high accuracy and real-time performance,
marking it a potential tool for a variety of applications, including those
focused on mobile-side human posture estimation. The code and models for this
algorithm will be made publicly accessible
Photonic nodal lines with quadrupole Berry curvature distribution
In periodic systems, nodal lines are loops in the three-dimensional momentum
space where two bands are degenerate with each other. Nodal lines exhibit rich
topological features as they can take various configurations such as rings,
links, chains and knots. These line nodes are usually protected by mirror or PT
symmetry. Here we propose and demonstrate a novel type of photonic straight
nodal lines in a D2d meta-crystal which are protected by roto-inversion time
(roto-PT) symmetry. The nodal lines are located at the central axis and hinges
of the Brillouin zone. They appear as quadrupole sources of Berry curvature
flux and allow for the precise control of the quadrupole strength.
Interestingly, there exist topological surface states at all three cutting
surfaces, as guaranteed by the pi-quantized Zak phases along all three
directions. As frequency changes, the surface state equi-frequency contours
evolve from closed to open contours, and become straight lines at a critical
transition frequency, at which diffraction-less surface wave propagation are
demonstrated, paving way towards development of super-imaging photonic devices
Intrinsic triple degeneracy point bounded by nodal surfaces in chiral photonic crystal
In periodic systems, band degeneracies are usually protected and classified
by spatial symmetries. However, the Gamma point at zero-frequency of a photonic
system is an intrinsic degeneracy due to the polarization degree of freedom of
electromagnetic waves. We show here that in chiral photonic crystals, such an
intrinsic degeneracy node carries +(-)2 chiral topological charge and the
topological characters is the same as a spin-1 Weyl point manifested as a
triple degeneracy of two linear propagating bands intersecting a flat band
representing the electrostatic solution. Such an intrinsic triple degeneracy
point (TDP) at Gamma is usually buried in bulk band projections and the
topological charge at photonic zero-frequency has never been observed. Here, by
imposing space-group screw symmetry to the chiral photonic crystal, the
Brillouin zone boundary is transformed into an oppositely charged nodal surface
enclosing the Gamma point. The emergent Fermi-arcs on sample surface are then
forced to connect the bulk band projections of these topological singularities,
revealing the embedded non-trivial topology
Characterization of a thermostable β-glucosidase from Aspergillus fumigatus Z5, and its functional expression in Pichia pastoris X33
<p>Abstract</p> <p>Background</p> <p>Recently, the increased demand of energy has strongly stimulated the research on the conversion of lignocellulosic biomass into reducing sugars for the subsequent production, and β-glucosidases have been the focus because of their important roles in a variety fundamental biological processes and the synthesis of useful β-glucosides. Although the β-glucosidases of different sources have been investigated, the amount of β-glucosidases are insufficient for effective conversion of cellulose. The goal of this work was to search for new resources of β-glucosidases, which was thermostable and with high catalytic efficiency.</p> <p>Results</p> <p>In this study, a thermostable native β-glucosidase (nBgl3), which is secreted by the lignocellulose-decomposing fungus <it>Aspergillus fumigatus </it>Z5, was purified to electrophoretic homogeneity. Internal sequences of nBgl3 were obtained by LC-MS/MS, and its encoding gene, <it>bgl3</it>, was cloned based on the peptide sequences obtained from the LC-MS/MS results. <it>bgl</it>3 contains an open reading frame (ORF) of 2622 bp and encodes a protein with a predicted molecular weight of 91.47 kDa; amino acid sequence analysis of the deduced protein indicated that nBgl3 is a member of the glycoside hydrolase family 3. A recombinant β-glucosidase (rBgl3) was obtained by the functional expression of <it>bgl</it>3 in <it>Pichia pastoris </it>X33. Several biochemical properties of purified nBgl3 and rBgl3 were determined - both enzymes showed optimal activity at pH 6.0 and 60°C, and they were stable for a pH range of 4-7 and a temperature range of 50 to 70°C. Of the substrates tested, nBgl3 and rBgl3 displayed the highest activity toward 4-Nitrophenyl-β-D-glucopyranoside (pNPG), with specific activities of 103.5 ± 7.1 and 101.7 ± 5.2 U mg<sup>-1</sup>, respectively. However, these enzymes were inactive toward carboxymethyl cellulose, lactose and xylan.</p> <p>Conclusions</p> <p>An native β-glucosidase nBgl3 was purified to electrophoretic homogeneity from the crude extract of <it>A. fumigatus </it>Z5. The gene <it>bgl</it>3 was cloned based on the internal sequences of nBgl3 obtained from the LC-MS/MS results, and the gene <it>bgl3 </it>was expressed in <it>Pichia pastoris </it>X33. The results of various biochemical properties of two enzymes including specific activity, pH stability, thermostability, and kinetic properties (Km and Vmax) indicated that they had no significant differences.</p
Experimental demonstration of non-adjacent band topology connecting multiple nodal links
Nodal links are special configurations of band degeneracies in the momentum
space, where nodal line branches encircle each other. In PT symmetric systems,
nodal lines can be topologically characterized using the eigenvector frame
rotations along an encircling loop and the linking structure can be described
with non-Abelian frame charges interacting among adjacent bands. In this paper,
we present a photonic multiple nodal links system, where non-adjacent band
topology is proposed to characterize the hidden relation between nodal lines
from non-adjacent band pairs. Through an orthogonal nodal chain, the nodal line
from the lower two bands predicts the existence of nodal lines formed between
the higher bands. We designed and fabricated a metamaterial, with which the
multiple nodal links and non-adjacent band topology are experimentally
demonstrated
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