5,215 research outputs found
Threshold for the Outbreak of Cascading Failures in Degree-degree Uncorrelated Networks
In complex networks, the failure of one or very few nodes may cause cascading
failures. When this dynamical process stops in steady state, the size of the
giant component formed by remaining un-failed nodes can be used to measure the
severity of cascading failures, which is critically important for estimating
the robustness of networks. In this paper, we provide a cascade of overload
failure model with local load sharing mechanism, and then explore the threshold
of node capacity when the large-scale cascading failures happen and un-failed
nodes in steady state cannot connect to each other to form a large connected
sub-network. We get the theoretical derivation of this threshold in
degree-degree uncorrelated networks, and validate the effectiveness of this
method in simulation. This threshold provide us a guidance to improve the
network robustness under the premise of limited capacity resource when creating
a network and assigning load. Therefore, this threshold is useful and important
to analyze the robustness of networks.Comment: 11 pages, 4 figure
Ultrasonic measurement of lubricant film thickness distribution of journal bearing
Most film thickness measurement methods damage the working surface of a bearing and cannot measure the minimum film thickness, making it difficult to reveal the lubrication state and warn of wear. Two non-intrusive ultrasonic methods were proposed for measuring the film thickness distribution of the bearing, i.e., the full circumferential measurement and the prediction based on limited measuring points. The ultrasonic recognition model of film thickness was built. A film thickness measuring device and its calibration device were constructed. A calibration experiment in the range of 1–150 µm and a measurement experiment of the bearing’s film thickness distribution were carried out. The results showed that in the calibration range, the relative error of most recognition values was less than ±5%, and some are less than 3%. The identification accuracy of the spring model has a zoned phenomenon. The relative difference between the experimental and the simulated values of the film thickness was less than 8% under most working conditions. The predicted values of eccentricity, attitude angle, and minimum film thickness have a small difference from the simulated values, indicating that the accuracy of the measurement method is high
3D Interacting Hand Pose Estimation by Hand De-occlusion and Removal
Estimating 3D interacting hand pose from a single RGB image is essential for
understanding human actions. Unlike most previous works that directly predict
the 3D poses of two interacting hands simultaneously, we propose to decompose
the challenging interacting hand pose estimation task and estimate the pose of
each hand separately. In this way, it is straightforward to take advantage of
the latest research progress on the single-hand pose estimation system.
However, hand pose estimation in interacting scenarios is very challenging, due
to (1) severe hand-hand occlusion and (2) ambiguity caused by the homogeneous
appearance of hands. To tackle these two challenges, we propose a novel Hand
De-occlusion and Removal (HDR) framework to perform hand de-occlusion and
distractor removal. We also propose the first large-scale synthetic amodal hand
dataset, termed Amodal InterHand Dataset (AIH), to facilitate model training
and promote the development of the related research. Experiments show that the
proposed method significantly outperforms previous state-of-the-art interacting
hand pose estimation approaches. Codes and data are available at
https://github.com/MengHao666/HDR.Comment: ECCV202
Differential Diagnosis of Solitary Pulmonary Inflammatory Lesions and Peripheral Lung Cancers with Contrast-enhanced Computed Tomography
OBJECTIVES: To clarify differences between solitary pulmonary inflammatory lesions and peripheral lung cancers with contrast-enhanced computed tomography. METHODS: In total, 64 and 132 patients with solitary pulmonary inflammatory masses/nodules and peripheral lung cancers, respectively, were enrolled in this study. Their computed tomographic findings were summarized and compared retrospectively. RESULTS: Compared with the peripheral lung cancers, the inflammatory lesions were located closer to the pleura (
Controlling mass and energy diffusion with metamaterials
Diffusion driven by temperature or concentration gradients is a fundamental
mechanism of energy and mass transport, which inherently differs from wave
propagation in both physical foundations and application prospects. Compared
with conventional schemes, metamaterials provide an unprecedented potential for
governing diffusion processes, based on emerging theories like the
transformation and the scattering cancellation theory, which enormously
expanded the original concepts and suggest innovative metamaterial-based
devices. We hereby use the term ``diffusionics'' to generalize these remarkable
achievements in various energy (e.g., heat) and mass (e.g., particles and
plasmas) diffusion systems. For clarity, we categorize the numerous studies
appeared during the last decade by diffusion field (i.e., heat, particles, and
plasmas) and discuss them from three different perspectives: the theoretical
perspective, to detail how the transformation principle is applied to each
diffusion field; the application perspective, to introduce various intriguing
metamaterial-based devices, such as cloaks and radiative coolers; and the
physics perspective, to connect with concepts of recent concern, such as
non-Hermitian topology, nonreciprocal transport, and spatiotemporal modulation.
We also discuss the possibility of controlling diffusion processes beyond
metamaterials. Finally, we point out several future directions for diffusion
metamaterial research, including the integration with artificial intelligence
and topology concepts.Comment: This review article has been accepted for publication in Rev. Mod.
Phy
Theaflavin Ameliorates Cerebral Ischemia-Reperfusion Injury in Rats Through Its Anti-Inflammatory Effect and Modulation of STAT-1
Theaflavin, a major constituent of black tea, possesses biological functions such as the antioxidative, antiviral, and anti-inflammatory ones. The purpose of this study was to verify whether theaflavin reduces focal cerebral ischemia injury in a rat model of middle cerebral artery occlusion (MCAO). Male Sprague-Dawley rats were anesthetized and subjected to 2 hours of MCAO followed 24 hours reperfusion. Theaflavin administration (5, 10, and 20 mg/kg, IV) ameliorated infarct and edema volume. Theaflavin inhibited leukocyte infiltration and expression of ICAM-1, COX-2, and iNOS in injured brain. Phosphorylation of STAT-1, a protein which mediates intracellular signaling to the nucleus, was enhanced 2-fold over that of sham group and was inhibited by theaflavin. Our study demonstrated that theaflavin significantly protected neurons from cerebral ischemia-reperfusion injury by limiting leukocyte infiltration and expression of ICAM-1, and suppressing upregulation of inflammatory-related prooxidative enzymes (iNOS and COX-2) in ischemic brain via, at least in part, reducing the phosphorylation of STAT-1
- …