6,871 research outputs found
Bearing angle based cooperative source localization
© 2014 IEEE. This paper deals with the cooperative source localization problem with the goal of having an accurate estimate of the coordinate of the source cooperatively by a group of unicycle-type mobile agents. Neither absolute positioning information nor a common sense of direction is shared by the agents. Each agent gets its estimate about the source's coordinate in its own local frame based on the bearing measurements about its neighbors (that may or may not include the source) together with its own linear and angular speed information. A continuous time estimation scheme and a distributed fusion scheme are proposed for this goal such that the source's relative coordinate can be estimated at any time by each agent no matter whether it can directly detect the source or not. The globally asymptotic convergence of the estimation scheme and the fusion scheme is rigorously analyzed. Simulation results are also provided to verify the effectiveness of the proposed algorithms
Multiresolution Feature Guidance Based Transformer for Anomaly Detection
Anomaly detection is represented as an unsupervised learning to identify
deviated images from normal images. In general, there are two main challenges
of anomaly detection tasks, i.e., the class imbalance and the unexpectedness of
anomalies. In this paper, we propose a multiresolution feature guidance method
based on Transformer named GTrans for unsupervised anomaly detection and
localization. In GTrans, an Anomaly Guided Network (AGN) pre-trained on
ImageNet is developed to provide surrogate labels for features and tokens.
Under the tacit knowledge guidance of the AGN, the anomaly detection network
named Trans utilizes Transformer to effectively establish a relationship
between features with multiresolution, enhancing the ability of the Trans in
fitting the normal data manifold. Due to the strong generalization ability of
AGN, GTrans locates anomalies by comparing the differences in spatial distance
and direction of multi-scale features extracted from the AGN and the Trans. Our
experiments demonstrate that the proposed GTrans achieves state-of-the-art
performance in both detection and localization on the MVTec AD dataset. GTrans
achieves image-level and pixel-level anomaly detection AUROC scores of 99.0%
and 97.9% on the MVTec AD dataset, respectively
Electrochemical Properties of Boron-Doped Diamond Electrodes Prepared by Hot Cathode Direct Current Plasma CVD
A series of boron-doped diamond (BDD) films were deposited by using a hot cathode direct current plasma chemical vapor deposition(HCDC-PCVD) system with different ratios of CH4/H2/B(OCH3)3 (trimethylborate) gas mixture. The morphology, structure and quality of BDD films were controled by SEM, XRD and Raman measurements. The electrochemical properties of the BDD films were investigated by electrochemical methods. Cyclic voltammetric performances of the BDD films indicated that the main determinant in the electrochemical characteristics of BDD films was the boron doping amount. The threshold potential for oxygen evolution increased from 1 V to 2.5 V. Meanwhile, the electrochemical potential window of BDD films was enlarged from 2.2 V to 4.5 V when the B content was increased from 1.75 × 1019cm-3 to 2.4 × 1021 cm−3. The cyclic voltammograms of BDD films in K4Fe(CN)6 and K3Fe(CN)6 mixed solution indicated that the behavior of Fe(CN)6-3/-4 redox couple could be regarded as semi-reversible
DeepFlame: A deep learning empowered open-source platform for reacting flow simulations
In this work, we introduce DeepFlame, an open-source C++ platform with the
capabilities of utilising machine learning algorithms and pre-trained models to
solve for reactive flows. We combine the individual strengths of the
computational fluid dynamics library OpenFOAM, machine learning framework
Torch, and chemical kinetics program Cantera. The complexity of cross-library
function and data interfacing (the core of DeepFlame) is minimised to achieve a
simple and clear workflow for code maintenance, extension and upgrading. As a
demonstration, we apply our recent work on deep learning for predicting
chemical kinetics (Zhang et al. Combust. Flame vol. 245 pp. 112319, 2022) to
highlight the potential of machine learning in accelerating reacting flow
simulation. A thorough code validation is conducted via a broad range of
canonical cases to assess its accuracy and efficiency. The results demonstrate
that the convection-diffusion-reaction algorithms implemented in DeepFlame are
robust and accurate for both steady-state and transient processes. In addition,
a number of methods aiming to further improve the computational efficiency,
e.g. dynamic load balancing and adaptive mesh refinement, are explored. Their
performances are also evaluated and reported. With the deep learning method
implemented in this work, a speed-up of two orders of magnitude is achieved in
a simple hydrogen ignition case when performed on a medium-end graphics
processing unit (GPU). Further gain in computational efficiency is expected for
hydrocarbon and other complex fuels. A similar level of acceleration is
obtained on an AI-specific chip - deep computing unit (DCU), highlighting the
potential of DeepFlame in leveraging the next-generation computing architecture
and hardware
A knowledge regularized hierarchical approach for emotion cause analysis
Emotion cause analysis, which aims to identify the reasons behind emotions, is a key topic in sentiment analysis. A variety of neural network models have been proposed recently, however, these previous models mostly focus on the learning architecture with local textual information, ignoring the discourse and prior knowledge, which play crucial roles in human text comprehension. In this paper, we propose a new method to extract emotion cause with a hierarchical neural model and knowledge-based regularizations, which aims to incorporate discourse context information and restrain the parameters by sentiment lexicon and common knowledge. The experimental results demonstrate that our proposed method achieves the state-of-the-art performance on two public datasets in different languages (Chinese and English), outperforming a number of competitive baselines by at least 2.08% in F-measure
Elevation of Inducible Nitric Oxide Synthase and Cyclooxygenase-2 Expression in the Mouse Brain after Chronic Nonylphenol Exposure
The present study was performed to investigate the effects of chronic administration of nonylphenol (NP) on the expression of inflammation-related genes in the brains of mice. NP was given orally by gavages at 0, 50, 100, and 200 mg/kg/d. The expression of inflammatory enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), was evaluated by immunohistochemistry and immunoblotting assays. The nitric oxide (NO) level and nitric oxide synthase (NOS) activity were also measured by biochemical analyses. The results showed that NP at a high dose (200 mg/kg/d) significantly increased the expression of iNOS and COX-2 in both the hippocampus and cortex. In parallel with the increase in iNOS expression, the NO level was significantly greater at the dose of 200 mg/kg/d, compared to the control. The activity of NOS was also increased in the brain of mice at the dose of 100 and 200 mg/kg/d. These findings demonstrate that NP may have the potential to induce the chronic inflammation or cause neurotoxicity in the mouse brain
Neural Free-Viewpoint Relighting for Glossy Indirect Illumination
Precomputed Radiance Transfer (PRT) remains an attractive solution for
real-time rendering of complex light transport effects such as glossy global
illumination. After precomputation, we can relight the scene with new
environment maps while changing viewpoint in real-time. However, practical PRT
methods are usually limited to low-frequency spherical harmonic lighting.
All-frequency techniques using wavelets are promising but have so far had
little practical impact. The curse of dimensionality and much higher data
requirements have typically limited them to relighting with fixed view or only
direct lighting with triple product integrals. In this paper, we demonstrate a
hybrid neural-wavelet PRT solution to high-frequency indirect illumination,
including glossy reflection, for relighting with changing view. Specifically,
we seek to represent the light transport function in the Haar wavelet basis.
For global illumination, we learn the wavelet transport using a small
multi-layer perceptron (MLP) applied to a feature field as a function of
spatial location and wavelet index, with reflected direction and material
parameters being other MLP inputs. We optimize/learn the feature field
(compactly represented by a tensor decomposition) and MLP parameters from
multiple images of the scene under different lighting and viewing conditions.
We demonstrate real-time (512 x 512 at 24 FPS, 800 x 600 at 13 FPS) precomputed
rendering of challenging scenes involving view-dependent reflections and even
caustics.Comment: 13 pages, 9 figures, to appear in cgf proceedings of egsr 202
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