2,126 research outputs found
Equivalence between Time Series Predictability and Bayes Error Rate
Predictability is an emerging metric that quantifies the highest possible
prediction accuracy for a given time series, being widely utilized in assessing
known prediction algorithms and characterizing intrinsic regularities in human
behaviors. Lately, increasing criticisms aim at the inaccuracy of the estimated
predictability, caused by the original entropy-based method. In this brief
report, we strictly prove that the time series predictability is equivalent to
a seemingly unrelated metric called Bayes error rate that explores the lowest
error rate unavoidable in classification. This proof bridges two independently
developed fields, and thus each can immediately benefit from the other. For
example, based on three theoretical models with known and controllable upper
bounds of prediction accuracy, we show that the estimation based on Bayes error
rate can largely solve the inaccuracy problem of predictability.Comment: 1 Figure, 1 Table, 5 Page
Cloze Test Helps: Effective Video Anomaly Detection via Learning to Complete Video Events
As a vital topic in media content interpretation, video anomaly detection
(VAD) has made fruitful progress via deep neural network (DNN). However,
existing methods usually follow a reconstruction or frame prediction routine.
They suffer from two gaps: (1) They cannot localize video activities in a both
precise and comprehensive manner. (2) They lack sufficient abilities to utilize
high-level semantics and temporal context information. Inspired by
frequently-used cloze test in language study, we propose a brand-new VAD
solution named Video Event Completion (VEC) to bridge gaps above: First, we
propose a novel pipeline to achieve both precise and comprehensive enclosure of
video activities. Appearance and motion are exploited as mutually complimentary
cues to localize regions of interest (RoIs). A normalized spatio-temporal cube
(STC) is built from each RoI as a video event, which lays the foundation of VEC
and serves as a basic processing unit. Second, we encourage DNN to capture
high-level semantics by solving a visual cloze test. To build such a visual
cloze test, a certain patch of STC is erased to yield an incomplete event (IE).
The DNN learns to restore the original video event from the IE by inferring the
missing patch. Third, to incorporate richer motion dynamics, another DNN is
trained to infer erased patches' optical flow. Finally, two ensemble strategies
using different types of IE and modalities are proposed to boost VAD
performance, so as to fully exploit the temporal context and modality
information for VAD. VEC can consistently outperform state-of-the-art methods
by a notable margin (typically 1.5%-5% AUROC) on commonly-used VAD benchmarks.
Our codes and results can be verified at github.com/yuguangnudt/VEC_VAD.Comment: To be published as an oral paper in Proceedings of the 28th ACM
International Conference on Multimedia (ACM MM '20). 9 pages, 7 figure
Strangeon matter and strangeon stars in a linked bag model
Inspired by various astrophysical phenomenons, it was suggested that
pulsar-like compact stars may in fact be strangeon stars, comprised entirely of
strangeons (quark-clusters with three-light-flavor symmetry) and a small amount
of electrons. To examine such possibilities, in this work we propose a linked
bag model, which can be adopted for strong condensed matter in both 2-flavoured
(nucleons) and 3-flavoured (hyperons, strangeons, etc.) scenarios. The model
parameters are calibrated to reproduce the saturation properties of nuclear
matter, which are later applied to hyperonic matter and strangeon matter. The
obtained energy per baryon of strangeon matter is reduced if we adopt larger
quark numbers inside a strangeon, which stiffens the equation of state and
consequently increases the maximum mass of strangeon stars. In a large
parameter space, the maximum mass and tidal deformability of strangeon stars
predicted in the linked bag model are consistent with the current astrophysical
constraints. It is found that the maximum mass of strangeon stars can be as
large as , while the tidal deformability of a
strangeon star lies in the range of .
More refined theoretical efforts as well as observational tests to these
results are necessary in the future
Influence of excipients on spray-dried powders for inhalation
Two areas attracting considerable attention when developing effective pulmonary drug delivery systems include the improvement of aerosolisation efficiency of the inhaled formulation and the controlled release of drug from the formulation following deposition within the lung. In this study, four saccharides were employed as excipients in the preparation of spray-dried powder formulations for the pulmonary drug delivery. Beta-cyclodextrin-, starch-, and sodium carboxymethylcellulose (NaCMC)-based spray-dried powders showed a significant (one-way ANOVA, Duncan's test, p < 0.05) increase in lower stage drug deposition in the Next Generation Impactor (NGI) when compared to lactose-based spray-dried powders. Furthermore, NaCMC-based spray-dried powder formulations exhibited a sustained drug release profile in dissolution testing; approximately 80% of salbutamol sulphate was released after an hour, whereas drug from the lactose-based spray-dried powder formulation was released within 5 min. Our results clearly demonstrate that the inclusion of NaCMC in spray-dried powder formulations increases the aerosolisation efficiency of the powder and also offers the potential for sustained drug release, which may be of benefit in the treatment of local and systemic conditions
Numerical model for the non-linear dynamic analysis of multi-storey structures with semi-rigid joints with specific reference to the Algerian code
Epididymis rhabdomyoma: A case report and literature review
Genital rhabdomyoma is very rare tumor that usually occurs in the vulvar of young women. Epididymis rhabdomyoma in a young man is extremely uncommon and has rarely been reported. Here, we report a case of epididymis rhabdomyoma of a 17-year-old man and review the literatures. VIRTUAL SLIDE: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/117762822469279
Food Markets with Live Birds as Source of Avian Influenza
A patient may have been infected with highly pathogenic avian influenza virus H5N1 in Guangzhou, People's Republic of China, at a food market that had live birds. Virus genes were detected in 1 of 79 wire cages for birds at 9 markets. One of 110 persons in the poultry business at markets had neutralizing antibody against H5N1.link_to_subscribed_fulltex
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Unprecedented and highly stable lithium storage capacity of (001) faceted nanosheet-constructed hierarchically porous TiO2/rGO hybrid architecture for high-performance Li-ion batteries.
Active crystal facets can generate special properties for various applications. Herein, we report a (001) faceted nanosheet-constructed hierarchically porous TiO2/rGO hybrid architecture with unprecedented and highly stable lithium storage performance. Density functional theory calculations show that the (001) faceted TiO2 nanosheets enable enhanced reaction kinetics by reinforcing their contact with the electrolyte and shortening the path length of Li+ diffusion and insertion-extraction. The reduced graphene oxide (rGO) nanosheets in this TiO2/rGO hybrid largely improve charge transport, while the porous hierarchy at different length scales favors continuous electrolyte permeation and accommodates volume change. This hierarchically porous TiO2/rGO hybrid anode material demonstrates an excellent reversible capacity of 250 mAh g-1 at 1 C (1 C = 335 mA g-1) at a voltage window of 1.0-3.0 V. Even after 1000 cycles at 5 C and 500 cycles at 10 C, the anode retains exceptional and stable capacities of 176 and 160 mAh g-1, respectively. Moreover, the formed Li2Ti2O4 nanodots facilitate reversed Li+ insertion-extraction during the cycling process. The above results indicate the best performance of TiO2-based materials as anodes for lithium-ion batteries reported in the literature
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