210 research outputs found

    Facial Motion Prior Networks for Facial Expression Recognition

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    Deep learning based facial expression recognition (FER) has received a lot of attention in the past few years. Most of the existing deep learning based FER methods do not consider domain knowledge well, which thereby fail to extract representative features. In this work, we propose a novel FER framework, named Facial Motion Prior Networks (FMPN). Particularly, we introduce an addition branch to generate a facial mask so as to focus on facial muscle moving regions. To guide the facial mask learning, we propose to incorporate prior domain knowledge by using the average differences between neutral faces and the corresponding expressive faces as the training guidance. Extensive experiments on three facial expression benchmark datasets demonstrate the effectiveness of the proposed method, compared with the state-of-the-art approaches.Comment: VCIP 2019, Oral. Code is available at https://github.com/donydchen/FMPN-FE

    Adaptive Sliding Mode Fault Tolerant Control for Autonomous Vehicle With Unknown Actuator Parameters and Saturated Tire Force Based on the Center of Percussion

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    With consideration of tire force saturation in vehicle motions, a novel path-following controller is developed for autonomous vehicles with unknown-bound disturbances and unknown actuator parameters. An adaptive sliding-mode fault-tolerant control (ASM-FTC) strategy is designed to stabilize the path-following errors without any information of disturbance boundaries, actuator fault boundaries and steering ratio from the steering wheel to the front wheels. By selecting the distance from the center of gravity to the center of percussion as the preview length, the effects of the lateral rear-tire force are decoupled and cancelled out, and then the preview error, which represents the path-following performance, can be only commanded by the front-tire force. To further address the issue of unknown tire-road friction limits, a modified ASM-FTC strategy is presented to improve the path-following performance as the lateral tire force is saturated. Simulation results show that the modified ASM-FTC controller demonstrates superior tracking performance over the normal ASM-FTC while the autonomous vehicle follows desired paths

    Enhanced photocatalytic oxidation of SO2 on TiO2 surface by Na2CO3 modification

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    The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.cej.2018.05.128 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/The effects of Na2CO3 on the photocatalytic oxidation (PCO) of SO2 with UV irradiated TiO2 (P25) were studied using a fixed bed reactor. Na2CO3 was loaded onto P25 using a wet coating method. The PCO efficiency for SO2 with P25 was enhanced by 1.6 and 10.6 times using 0.05 M and 0.2 M Na2CO3 modified P25, respectively. The enhancement of the photocatalytic activity of P25 by Na2CO3 was observed only with the presence of water vapor. Low temperature (113 K) electron spinning resonance (ESR) analysis showed that Na2CO3 promoted the photoinduced electron-hole separation by trapping valance band holes and forming carbonate radicals (CO3−). The ESR spin trapping analyses showed a remarkable increase in the intensity of [DMPO-OH] adducts with the addition of Na2CO3. This increase phenomena indicates that more reactive species were formed on the P25 surface. The deposited Na2CO3 inhibited the recombination of electron-hole pairs and promoted the generation of hydroxyl radicals (OH), most likely through the photo-reduction of O2 adsorbed by the conduction band electrons. The generated •OH radicals reacted with SO2 rapidly and improved the PCO effectiveness of P25.National Key Research and Development Program of China ["2017YFB0603903"

    A wet process for oxidation-absorption of nitric oxide by persulfate/calcium peroxide

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    The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.cej.2018.05.145 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/This study develops and evaluates a novel wet method for NO removal using a Na2S2O8/CaO2 solution. The effects of these two components both and alone in solution, Na2S2O8 concentration, CaO2 concentration, initial pH, reaction temperature, and the concentrations of NO and O2 on NO removal efficiency were evaluated using a bubbling reactor. The combination of Na2S2O8 and CaO2 had a synergistic effect on NO removal efficiency. NO removal was effected by CaO2 concentration, reaction temperature and the initial solution pH, while Na2S2O8 concentration and O2 concentration had little effect. The NO removal efficiency decreased linearly from 94.5 % to 75.1 % when the NO concentration increased from 139 to 559 ppm. The products were characterized using XRD, XPS and IC, and CaSO4·2H2O, NO3− and SO42− were found to be the main products. The EPR analysis showed that free radicals of O2−, SO4− and OH were the key species involved in the NO removal process. Finally, the corresponding reaction mechanisms were proposed.International S&T Cooperation Program of China [Grant No. 2015DFG61910

    On the validity of the local Fourier analysis

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    Local Fourier analysis (LFA) is a useful tool in predicting the convergence factors of geometric multigrid methods (GMG). As is well known, on rectangular domains with periodic boundary conditions this analysis gives the exact convergence factors of such methods. In this work, using the Fourier method, we extend these results by proving that such analysis yields the exact convergence factors for a wider class of problems
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