322 research outputs found
Efficient Localized Inference for Large Graphical Models
We propose a new localized inference algorithm for answering marginalization
queries in large graphical models with the correlation decay property. Given a
query variable and a large graphical model, we define a much smaller model in a
local region around the query variable in the target model so that the marginal
distribution of the query variable can be accurately approximated. We introduce
two approximation error bounds based on the Dobrushin's comparison theorem and
apply our bounds to derive a greedy expansion algorithm that efficiently guides
the selection of neighbor nodes for localized inference. We verify our
theoretical bounds on various datasets and demonstrate that our localized
inference algorithm can provide fast and accurate approximation for large
graphical models
The Cognitive Load of Observation Tasks in 3D Video is Lower Than That in 2D Video
We are exposed to more and more 3D videos, some for entertainment and some
for scientific research. Some experiments using 3D video as a stimulus focus
only on its visual effect. We studied the cognitive difference between 3D and
2D videos by analyzing EEG. This research adopts a 2 x 4 experimental design,
including 2D and 3D versions of 4 video scenes. These four video scenes can be
classified into two simple task scenes and two complex task scenes. The simple
task scenario and the complex task scenario each contain a video with violent
content changes and a calm video. Subjects need to watch eight videos. We
recorded the EEG information of the subjects and analyzed the power of alpha
and theta oscillations. On this basis, we calculated the cognitive load index
(CLI), which can be used as an indicator of cognitive load. The results showed
that 3D videos that required subjects to perform simple tasks brought higher
cognitive load to most subjects. When the video contains complex tasks, the
cognitive load of subjects does not show similar regularity. Specifically, only
half of the people had higher cognitive load when watching the 3D version of
the video than when watching the 2D version. In addition, the cognitive load
level of subjects showed significant individual differencesComment: 7 pages, 18 figure
VarietySound: Timbre-Controllable Video to Sound Generation via Unsupervised Information Disentanglement
Video to sound generation aims to generate realistic and natural sound given
a video input. However, previous video-to-sound generation methods can only
generate a random or average timbre without any controls or specializations of
the generated sound timbre, leading to the problem that people cannot obtain
the desired timbre under these methods sometimes. In this paper, we pose the
task of generating sound with a specific timbre given a video input and a
reference audio sample. To solve this task, we disentangle each target sound
audio into three components: temporal information, acoustic information, and
background information. We first use three encoders to encode these components
respectively: 1) a temporal encoder to encode temporal information, which is
fed with video frames since the input video shares the same temporal
information as the original audio; 2) an acoustic encoder to encode timbre
information, which takes the original audio as input and discards its temporal
information by a temporal-corrupting operation; and 3) a background encoder to
encode the residual or background sound, which uses the background part of the
original audio as input. To make the generated result achieve better quality
and temporal alignment, we also adopt a mel discriminator and a temporal
discriminator for the adversarial training. Our experimental results on the VAS
dataset demonstrate that our method can generate high-quality audio samples
with good synchronization with events in video and high timbre similarity with
the reference audio
Numerical simulation of the effect of flange radial length on strain growth of cylindrical containment vessels
In this paper, the effect of radial length of flange on the strain growth in the elastic range of the cylindrical shell is studied by numerical simulation using LS-DYNA. It is found that the influence of the flange length on the first strain peak is small. As the radial length of the flange increases, the bending disturbance of the various frequencies of the cylindrical shell is excited which makes the linear modal coupling response is enhanced, so that the strain growth factor is increased. When more high-frequency parts are introduced into the strain response, the strain growth time will be correspondingly shortened. Therefore, it is recommended to use a flange as small as possible when designing the explosion containment vessel
The study on the antioxidant activity of polysaccharides isolated from Polygonatum odoratum (Mill.) Druce
The polysaccharides isolated from Polygonatum odoratum (Mill.) Druce (POPs) by water extraction, after precipitation with ethanol were purified through deproteinization, decolorization, dialysis, and column chromatography leading to a purified polysaccharide (POPs-I) content of 90.7 %. The scavenging of oxygen free radicals and inhibition of lipid peroxidation (LPO) by POPs-I were analyzed using a colorimetric method. The results showed that the hydroxyl radical scavenging ability of the polysaccharides was weaker than that of benzoic acid, but stronger than those of ascorbic acid and mannitol, and that the superoxide anion radical scavenging ability was inferior to those of all three. When the concentration was higher than 1.0 mg/mL, the POPs-I could inhibit LPO by superoxide anion radicals to a certain degree. Therefore, this work suggests that POPs-I are potential antioxidant agents in medicine and functional food
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