77 research outputs found
Multiscale Representation for Real-Time Anti-Aliasing Neural Rendering
The rendering scheme in neural radiance field (NeRF) is effective in
rendering a pixel by casting a ray into the scene. However, NeRF yields blurred
rendering results when the training images are captured at non-uniform scales,
and produces aliasing artifacts if the test images are taken in distant views.
To address this issue, Mip-NeRF proposes a multiscale representation as a
conical frustum to encode scale information. Nevertheless, this approach is
only suitable for offline rendering since it relies on integrated positional
encoding (IPE) to query a multilayer perceptron (MLP). To overcome this
limitation, we propose mip voxel grids (Mip-VoG), an explicit multiscale
representation with a deferred architecture for real-time anti-aliasing
rendering. Our approach includes a density Mip-VoG for scene geometry and a
feature Mip-VoG with a small MLP for view-dependent color. Mip-VoG encodes
scene scale using the level of detail (LOD) derived from ray differentials and
uses quadrilinear interpolation to map a queried 3D location to its features
and density from two neighboring downsampled voxel grids. To our knowledge, our
approach is the first to offer multiscale training and real-time anti-aliasing
rendering simultaneously. We conducted experiments on multiscale datasets, and
the results show that our approach outperforms state-of-the-art real-time
rendering baselines
Improving Shape Retrieval by Integrating AIR and Modified Mutual k
In computer vision, image retrieval remained a significant problem and recent resurgent of image retrieval also relies on other postprocessing methods to improve the accuracy instead of solely relying on good feature representation. Our method addressed the shape retrieval of binary images. This paper proposes a new integration scheme to best utilize feature representation along with contextual information. For feature representation we used articulation invariant representation; dynamic programming is then utilized for better shape matching followed by manifold learning based postprocessing modified mutual kNN graph to further improve the similarity score. We conducted extensive experiments on widely used MPEG-7 database of shape images by so-called bulls-eye score with and without normalization of modified mutual kNN graph which clearly indicates the importance of normalization. Finally, our method demonstrated better results compared to other methods. We also computed the computational time with another graph transduction method which clearly shows that our method is computationally very fast. Furthermore, to show consistency of postprocessing method, we also performed experiments on challenging ORL and YALE face datasets and improved baseline results
Mesoporous Ti<sub>0.5</sub>Cr<sub>0.5</sub>N for trace H<sub>2</sub>S detection with excellent long-term stability
ALMA High-resolution Spectral Survey of Thioformaldehyde (H2CS) Towards Massive Protoclusters
Investigating the temperature and density structures of gas in massive
protoclusters is crucial for understanding the chemical properties therein. In
this study, we present observations of the continuum and thioformaldehyde
(H2CS) lines at 345 GHz of 11 massive protoclusters using the Atacama Large
Millimeter/submillimeter Array (ALMA) telescope. High spatial resolution and
sensitivity observations have detected 145 continuum cores from the 11 sources.
H2CS line transitions are observed in 72 out of 145 cores, including line-rich
cores, warm cores and cold cores. The H2 column densities of the 72 cores are
estimated from the continuum emission which are larger than the density
threshold value for star formation, suggesting that H2CS can be widely
distributed in star-forming cores with different physical environments.
Rotation temperature and column density of H2CS are derived by use of the
XCLASS software. The results show the H2CS abundances increase as temperature
rises and higher gas temperatures are usually associated with higher H2CS
column densities. The abundances of H2CS are positively correlated with its
column density, suggesting that the H2CS abundances are enhanced from cold
cores, warm cores to line-rich cores in star forming regions.Comment: 23 pages, 7 figures, 6 tables, accepted by Ap
Genetic variants in IL1A and IL1B contribute to the susceptibility to 2009 pandemic H1N1 influenza A virus
Direct observational evidence of the multi-scale, dynamical mass accretion toward a high-mass star forming hub-filament system
There is growing evidence that high-mass star formation and hub-filament
systems (HFS) are intricately linked. The gas kinematics along the filaments
and the forming high-mass star(s) in the central hub are in excellent agreement
with the new generation of global hierarchical high-mass star formation models.
In this paper, we present an observational investigation of a typical HFS
cloud, G310.142+0.758 (G310 hereafter) which reveals unambiguous evidence of
mass inflow from the cloud scale via the filaments onto the forming
protostar(s) at the hub conforming with the model predictions. Continuum and
molecular line data from the ATOMS and MALT90 surveys are used that cover
different spatial scales. Three filaments (with total mass ) are identified converging toward the central hub region where
several signposts of high-mass star formation have been observed. The hub
region contains a massive clump () harbouring a central
massive core. Additionally, five outflow lobes are associated with the central
massive core implying a forming cluster. The observed large-scale, smooth and
coherent velocity gradients from the cloud down to the core scale, and the
signatures of infall motion seen in the central massive clump and core, clearly
unveil a nearly-continuous, multi-scale mass accretion/transfer process at a
similar mass infall rate of over all scales,
feeding the central forming high-mass protostar(s) in the G310 HFS cloud.Comment: Accepted to publish in ApJ. 10 pages with 6 figures and 2 table
Quantitative analysis of late gadolinium enhancement in hypertrophic cardiomyopathy: comparison of diagnostic performance in myocardial fibrosis between gadobutrol and gadopentetate dimeglumine
The purpose of this study was to compare different semi-automated late gadolinium enhancement (LGE) quantification techniques using gadobutrol and gadopentetate dimeglumine contrast agents with regard to the diagnosis of fibrotic myocardium in patients with hypertrophic cardiomyopathy (HCM). Thirty patients with HCM underwent two cardiac MRI protocols with use of gadobutrol and gadopentetate dimeglumine. Contrast-tonoise ratio (CNR) between LGE area and remote myocardium (CNRremote), between LGE area and left ventricular blood pool (CNRpool), and signal-to-noise ratio (SNR) in LGE were compared. The presence and quantity of LGE were determined by visual assessment. With signal threshold versus reference mean (STRM) based thresholds of 2 SD, 5 SD, and 6 SD above the mean signal intensity (SI) of reference myocardium, the full-width at half-maximum (FWHM) technique was used. The volume and segments of the LGE area were compared between the two types of contrast agents. LGE was present in 26 of 30 (86.6%) patients in both protocols. The CNRremote of fibrotic myocardium in gadobutrol and gadopentetate dimeglumine agents was 26.82 ± 14.24 and 21.46 ± 10.59, respectively (P < 0.05). The CNRpool was significantly higher in gadobutrol (9.32 ± 7.64 vs. 6.39 ± 6.11, P < 0.05). The SNR was higher in gadobutrol (33.36 ± 14.35 vs. 27.53 ± 10.91, P < 0.05). The volume of scar size in MR images acquired with gadobutrol were significantly higher than those with gadopentetate dimeglumine (P < 0.05), and the STRM of 5 SD technique showed the greatest agreement with visual assessment (ICC = 0.99) in both examinations. There was no significant difference in fibrotic segments of the fibrotic myocardium in the LGE area (P < 0.05). This study proved that the Gadobutrol was an effective contrast agent for LGE imaging with superior delineation of fibrotic myocardium as compared to gadopentetate dimeglumine. The 5 SD technique yields the closest approximation of the extent of LGE identified by visual assessment
Clinical value of patient-specific three-dimensional printing of congenital heart disease: Quantitative and qualitative assessments
Objective: Current diagnostic assessment tools remain suboptimal in demonstrating complex morphology of congenital heart disease (CHD). This limitation has posed several challenges in preoperative planning, communication in medical practice, and medical education. This study aims to investigate the dimensional accuracy and the clinical value of 3D printed model of CHD in the above three areas. Methods: Using cardiac computed tomography angiography (CCTA) data, a patient-specific 3D model of a 20-month-old boy with double outlet right ventricle was printed in Tango Plus material. Pearson correlation coefficient was used to evaluate correlation of the quantitative measurements taken at analogous anatomical locations between the CCTA images pre- and post-3D printing. Qualitative analysis was conducted by distributing surveys to six health professionals (two radiologists, two cardiologists and two cardiac surgeons) and three medical academics to assess the clinical value of the 3D printed model in these three areas. Results: Excellent correlation (r = 0.99) was noted in the measurements between CCTA and 3D printed model, with a mean difference of 0.23 mm. Four out of six health professionals found the model to be useful in facilitating preoperative planning, while all of them thought that the model would be invaluable in enhancing patient-doctor communication. All three medical academics found the model to be helpful in teaching, and thought that the students will be able to learn the pathology quicker with better understanding. Conclusion: The complex cardiac anatomy can be accurately replicated in flexible material using 3D printing technology. 3D printed heart models could serve as an excellent tool in facilitating preoperative planning, communication in medical practice, and medical education, although further studies with inclusion of more clinical cases are needed
Equity research - BYD Company Limited
Mestrado Bolonha em FinançasThis equity research project is committed to the valuation of BYD and was written in
line with the research report format recommended by the CFA Institute. The research
data and information involved were based on public information disclosed before
September 30, 2022, any other information after this date has not be considered.
As a leader and forerunner in China EV industry, BYD has created a series of miracles.
It is great respect for this company not only for its deep commitment to the green
product, but also for its pioneering spirit of enterprise. The company's share price has
soared since 2020, becoming Chinese “Tesla”, which makes the company more
special and worthy for studying.
Four different methods are adapted to valuate this company. The benchmark method
is based on DCF model, using WACC method to discount the FCFF and the terminal
value to get the enterprise value of CNY 918.89 billion. A BUY recommendation is
concluded according to the predicted price target of CNY 315.14 per share at the end
of 2022, implying an upside potential of 25.1% compared to the closing price of CNY
252.1 on September 30, 2022, with medium risk. Other three supplementary methods
including equity method, APV method, and relative valuation methods initiate the same
buy recommendation.Este projeto de Equity Research é vocacionado para a avaliação da BYD e foi
concluído conforme o formato de relatório de pesquisa recomendado pelo Instituto de
CFA. Os dados da pesquisa e as informações envolvidas foram baseados em
informações públicas divulgadas antes de 30 de setembro de 2022, quaisquer outras
informações após esta data não serão consideradas.
Sendo o líder e a precursora na indústria de EVs da China, a BYD criou uma série de
milagres. Tenho grande respeito por esta empresa não apenas pelo seu profundo
compromisso com o produto verde, mas também pelo seu espírito empreendedor
pioneiro. O preço das ações da empresa tem disparado desde 2020, tornando-se a
“Tesla” da China, o que faz dela uma empresa mais peculiar e digna de ser estudada.
No total, existem quatro métodos para avaliar esta empresa. O método de referência
é baseado no modelo DCF, usando WACC para descontar o FCFF e o valor terminal
para obter o valor da empresa, que é de CNY 918,89 bilhões. Uma recomendação de
COMPRA foi realizada, de acordo com o preço-alvo previsto de CNY 315,14 por ação,
no final de 2022, implicando um potencial de valorização de 25.1% em relação ao
preço de encerramento de CNY 252,1 por ação, em 30 de setembro de 2022, com o
risco médio. Outros três métodos complementares incluem o método de Equity, o
método de APV e o método de avaliação relativa, indicando a mesma recomendação
de compra.info:eu-repo/semantics/publishedVersio
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