13 research outputs found
The Fast Medical Image Segmentation of Target Region Based on Improved FM Algorithm
AbstractThis paper studies several kinds of image segmentation algorithm,and region-growing algorithm and fast level set matching algorithm FM are programmed by VC and verified,thereinto,the speed of segmentation of region-growing algorithm is fast.It is primarily affected by the identity of gray level of object region, for the inconsistent object region, excessive segmentation and missing segmentation will happen.The fast matching method can easily handle the geometric objects which topological structure is complex or changing, but the evolving curve also easily leak from the boundary, if there are holes in an object which has been segmented, it will not quite separate the interior outline of the object,so,aiming at the characteristics of medical image,an improved fast matching algorithm is presented in this paper, it can effectively enhance the image segmentation effect and prevent the loss of details of lines, and the internal change of topological structures of the objects can also be segmented better by it
Castling-ViT: Compressing Self-Attention via Switching Towards Linear-Angular Attention During Vision Transformer Inference
Vision Transformers (ViTs) have shown impressive performance but still
require a high computation cost as compared to convolutional neural networks
(CNNs), one reason is that ViTs' attention measures global similarities and
thus has a quadratic complexity with the number of input tokens. Existing
efficient ViTs adopt local attention (e.g., Swin) or linear attention (e.g.,
Performer), which sacrifice ViTs' capabilities of capturing either global or
local context. In this work, we ask an important research question: Can ViTs
learn both global and local context while being more efficient during
inference? To this end, we propose a framework called Castling-ViT, which
trains ViTs using both linear-angular attention and masked softmax-based
quadratic attention, but then switches to having only linear angular attention
during ViT inference. Our Castling-ViT leverages angular kernels to measure the
similarities between queries and keys via spectral angles. And we further
simplify it with two techniques: (1) a novel linear-angular attention
mechanism: we decompose the angular kernels into linear terms and high-order
residuals, and only keep the linear terms; and (2) we adopt two parameterized
modules to approximate high-order residuals: a depthwise convolution and an
auxiliary masked softmax attention to help learn both global and local
information, where the masks for softmax attention are regularized to gradually
become zeros and thus incur no overhead during ViT inference. Extensive
experiments and ablation studies on three tasks consistently validate the
effectiveness of the proposed Castling-ViT, e.g., achieving up to a 1.8% higher
accuracy or 40% MACs reduction on ImageNet classification and 1.2 higher mAP on
COCO detection under comparable FLOPs, as compared to ViTs with vanilla
softmax-based attentions.Comment: CVPR 202
The Extended Distribution of Baryons Around Galaxies
We summarize and reanalyze observations bearing upon missing galactic
baryons, where we propose a consistent picture for halo gas in L >~ L*
galaxies. The hot X-ray emitting halos are detected to 50-70 kpc, where
typically, M_hot(<50 kpc) ~ 5E9 Msun, and with density n \propto r^-3/2. When
extrapolated to R200, the gas mass is comparable to the stellar mass, but about
half of the baryons are still missing from the hot phase. If extrapolated to
1.9-3 R200, the baryon to dark matter ratio approaches the cosmic value.
Significantly flatter density profiles are unlikely for R < 50 kpc and they are
disfavored but not ruled out for R > 50 kpc. For the Milky Way, the hot halo
metallicity lies in the range 0.3-1 solar for R < 50 kpc. Planck measurements
of the thermal Sunyaev-Zeldovich effect toward stacked luminous galaxies
(primarily early-type) indicate that most of their baryons are hot, near the
virial temperature, and extend beyond R200. This stacked SZ signal is nearly an
order of magnitude larger than that inferred from the X-ray observations of
individual (mostly spiral) galaxies with M_* > 10^11.3 Msun. This difference
suggests that the hot halo properties are distinct for early and late type
galaxies, possibly due to different evolutionary histories. For the cooler gas
detected in UV absorption line studies, we argue that there are two absorption
populations: extended halos; and disks extending to ~50 kpc, containing most of
this gas, and with masses a few times lower than the stellar masses. Such
extended disks are also seen in 21 cm HI observations and in simulations.Comment: 22 pages, 20 figures, 2 tables, submitted to Ap
Rapid Determination of the Freshness of Lotus Seeds Using Surface Desorption Atmospheric Pressure Chemical Ionization-Mass Spectrometry with Multivariate Analyses
<p>Biomimetic piezoelectric nanocomposite membranes synergistically enhance osteogenesis of deproteinized bovine bone grafts</p>
Fluorographene with High Fluorine/Carbon Ratio: A Nanofiller for Preparing LowâÎș Polyimide Hybrid Films
Sufficient amounts of fluorographene
sheets with different sheet-size
and fluorine/carbon ratio were synthesized for preparing of fluorographene/polyimide
hybrids in order to explore the effect of fluorographene on the dielectric
properties of hybrid materials. It is found that the fluorine/carbon
ratio, width of band gap, and sheet-size of fluorographene play the
important roles in determining the final dielectric properties of
hybrids. The fluorographene with high fluorine/carbon ratio (F/C â
1) presents broaden band gap, enhanced hydrophobicity, good dispersity
and thermal stability, etc. Even at a very low filling, only 1 wt
%, its polyimide hybrids exhibited drastically reduced dielectric
constants as low as 2.1 without sacrificing thermal stability, improved
mechanical properties obviously and decreased water absorption by
about 120% to 1.0 wt %. This provides a novel route for improving
the dielectric properties of materials and a new thought to carry
out the application of fluorographene as an advanced material
Electroactive BaTiO<sub>3</sub> nanoparticle-functionalized fibrous scaffolds enhance osteogenic differentiation of mesenchymal stem cells
High-Yield Production of Highly Fluorinated Graphene by Direct Heating Fluorination of Graphene-oxide
By
employing honeycomb GO with large surface area as the starting
materials and using elemental fluorine, we developed a novel, straightforward
topotactic route toward highly fluorinated graphene in really large
quantities at low temperature. The value of F/C molar ratio approaches
to 1.02. Few-layer fluorinated graphene sheets are obtained, among
which the yield of monolayered FG sheet is about 10% and the number
of layers is mainly in the range of 2â5. Variations in morphology
and chemical structure of fluorinated graphene were explored, and
some physical properties were reported
Preparing Highly Fluorinated Multiwall Carbon Nanotube by Direct Heating-Fluorination during the Elimination of Oxygen-Related Groups
Pristine
and oxidized multiwalled carbon nanotubes (MWCNTs) were separately
prepared and directly fluorinated with F<sub>2</sub> through two different
routes: heating-fluorination and isothermal-fluorination. The amount
of fluorine atoms (hereinafter referred to as âF-contentâ)
bonding to the fluorinated samples was largely dependent on the modifing
route and chemical bonding of MWCNTs. The F-content of heating-fluorinated
pristine and oxidized MWCNTs was 3.2% and 9.2% respectively, which
were about 8 times and 18 times that of the corresponding isothermal-fluorinated
MWCNTs. According to structural analysis of samples before and after
fluorination, it was found that thermal elimination of oxygen-related
groups bonding to MWCNTs contributed to the formation of strongly
covalent CâF bonds during heating-fluorination. It was considered
that the oxygen-related groups provided reactive sites for the fluorination.
The fluorination reaction took place at an sp<sup>3</sup> carbon linking
with the oxygen-related groups and did not increase the density of
defect on MWCNTs. A radical-mediated mechanism is accepted for this
reaction. Thus, MWCNTs could be first oxidized to increase the number
of oxygen-related groups and then heating-fluorinated by F<sub>2</sub> directly to get highly fluorinated MWCNTs with stable CâF
bonds