Observer-based Adaptive Neural Network Output-feedback Control for Nonlinear Strict-feedback Discrete-time Systems

Wenqi Xu,Xiaoping Liu,Huanqing Wang,Yucheng Zhou 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.1

This paper focuses on an observer-based output-feedback controller design for a nonlinear discrete-timesystem. The major characteristics of this system is that all of the subsystems are in strict-feedback form and all thestates of the system are not measurable. An output tracking control problem is firstly considered in this paper. NNsare utilized to approximate unknown functions, while a state observer is designed to approximatethe unvailablestates. An adaptive controller is designed on the basis of the backstepping technique. On the basis of the Lyapunovanalysis approach, the boundedness of all the signals is provided. The feasibility of the proposed scheme is verifiedthrough a simulation example.

Ship Number Recognition Method Based on An improved CRNN Model

Wenqi Xu,Yuesheng Liu,Ziyang Zhong,Yang Chen,Jinfeng Xia,Yunjie Chen 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.3

Text recognition in natural scene images is a challenging problem in computer vision. The accurate identification of ship number characters can effectively improve the level of ship traffic management. However, due to the blurring caused by motion and text occlusion, the accuracy of ship number recognition is difficult to meet the actual requirements. To solve these problems, this paper proposes a dual-branch network based on the CRNN identification network. The network couples image restoration and character recognition. The CycleGAN module is used for blur restoration branch, and the Pix2pix module is used for character occlusion branch. The two are coupled to reduce the impact of image blur and occlusion. Input the recovered image into the text recognition branch to improve the recognition accuracy. After a lot of experiments, the model is robust and easy to train. Experiments on CTW datasets and real ship maps illustrate that our method can get more accurate results.

Histone lysine demethylases in mammalian embryonic development

Hongjie Shen,Wenqi Xu,Fei Lan 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Post-translational modifications, such as methylation, acetylation and phosphorylation, of histone proteins play important roles in regulating dynamic chromatin structure. Histone demethylation has become one of the most active research areas of epigenetics in the past decade. To date, with the exception of histone H3 lysine 79 methylation, the demethylases for all major lysine methylation sites have been discovered. These enzymes have been shown to be involved in various biological processes, with embryonic development being an exciting emerging area. This review will primarily discuss the involvement of these demethylases in the regulation of mammalian embryonic development, including their roles in embryonic stem cell pluripotency, primordial germ cell (PGC) formation and maternal-to-zygotic transition.

A Dynamic Control Method for Cavs Platoon Based on the MPC Framework and Safety Potential Field Model

Linheng Li,Jing Gan,Xu Qu,Wenqi Lu,Peipei Mao,Bin Ran 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.5

Safety and efficiency have always been significant challenges to the development of road traffic. Detailed vehicle motion information is the prerequisite for achieving optimal control of the platoon and improving traffic safety and efficiency. The connected and automated vehicles (CAVs) system has offered unprecedented opportunities for the real-time collection and processing of these detailed vehicle motion data. Based on the model predictive control (MPC) framework and safety potential field (SPF) model, we developed an alternative CAVs platoon dynamic control method. The SPF model was applied to describe the road risk distribution under the complex driving environment and was embedded in the MPC framework to optimize the vehicle dynamics from the perspective of capacity, safety, and energy-saving. Also, some experiments were performed to verify the validity of our platoon control strategy. Compared with the fixed time-headway strategy, our proposed strategy can increase the traffic capacity by about 24.4%, while ensuring safety and improving fuel economy. The results indicate that the novel CAVs platoon control methodology proposed in this paper can be potentially applied to alleviate various traffic problems (e.g., traffic congestion, traffic accidents, and high emissions).

Benchtop fabrication of three-dimensional reconfigurable microfluidic devices from paper-polymer composite.

Han, Yu Long,Wang, Wenqi,Hu, Jie,Huang, Guoyou,Wang, Shuqi,Lee, Won Gu,Lu, Tian Jian,Xu, Feng Royal Society of Chemistry 2013 Lab on a chip Vol.13 No.24

<P>We presented a benchtop technique that can fabricate reconfigurable, three-dimensional (3D) microfluidic devices made from a soft paper-polymer composite. This fabrication approach can produce microchannels at a minimal width of 100 μm and can be used to prototype 3D microfluidic devices by simple bending and stretching. The entire fabrication process can be finished in 2 hours on a laboratory bench without the need for special equipment involved in lithography. Various functional microfluidic devices (e.g., droplet generator and reconfigurable electronic circuit) were prepared using this paper-polymer hybrid microfluidic system. The developed method can be applied in a wide range of standard applications and emerging technologies such as liquid-phase electronics.</P>

miR-195/miR-497 Regulate CD274 Expression of Immune Regulatory Ligands in Triple-Negative Breast Cancer

Lianzhou Yang,Yuchen Cai,Dongsheng Zhang,Jian Sun,Chenyu Xu,Wenli Zhao,Wenqi Jiang,Chunhua Pan 한국유방암학회 2018 Journal of breast cancer Vol.21 No.4

Purpose: Immune suppression is common in patients with advanced breast cancer but the mechanisms underlying this phenomenon have not been sufficiently studied. In this study, we aimed to identify B7 family members that were able to predict the immune status of patients, and which may serve as potential targets for the treatment of breast cancer. We also aimed to identify microRNAs that may regulate the expression of B7 family members. Methods: The Cancer Genome Atlas data from 1,092 patients with breast cancer, including gene expression, microRNA expression and survival data, were used for statistical and survival analyses. Polymerase chain reaction and Western blot were used to measure messenger RNA and protein expression, respectively. Luciferase assay was used to investigate direct microRNA target. Results: Bioinformatic analysis predicted that microRNA (miR)-93, miR-195, miR-497, and miR-340 are potential regulators of the immune evasion of breast cancer cells, and that they exert this function by targeting CD274, PDCD1LG2, and NCR3LG1. We chose CD274 for further investigations. We found that miR-195, miR-497, and CD274 expression levels were inversely correlated in MDA-MB-231 cells, and miR-195 and miR-497 expressions mimic inhibited CD274 expression in vitro. Mechanistic investigations demonstrated that miR-195 and miR-497 directly target CD274 3´ untranslated region. Conclusion: Our data indicated that the level of B7 family members can predict the prognosis of breast cancer patients, and miR-195/miR-497 regulate CD274 expression in triple negative breast cancer. This regulation may further influence tumor progression and the immune tolerance mechanism in breast cancer and may be able to predict the effect of immunotherapy on patients.

Effects of exposure to trace pyriproxyfen on the intestinal bacterial diversity and immune signal pathways of silkworm (Bombyx mori) larvae

Lu Qingyu,Li Guoli,Lan Huangli,Yu Dongliang,Yin Xingcan,Yang Wenqi,Yang Zehao,He Chunhui,Mo Danmei,Xu Kaizun 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.2

Silkworm (Bombyx mori) is a widely used lepidopteran model insect. Pyriproxyfen is an insect growth regulator (IGR) that can be used to control pests such as lepidoptera and diptera, and there is no research about its in fluence on the intestinal bacterial diversity and immune signal pathway of non-target lepidopteran insect larvae. In this study, we treated fifth-instar silkworms with trace pyriproxyfen (10 − 4 mg/L). The results showed that the abundance and diversity of silkworm larvae intestinal flora at the level of phylum, class, order, family and genus were all changed. The function prediction result showed that the functional changes mainly focused on tran scription, amino acid transport and metabolism, carbohydrate transport and metabolism, signal transduction mechanisms, energy production and conversion et al. after exposure to trace pyriproxyfen. Furthermore, qRTPCR results showed that trace pyriproxyfen exposure activated the transcriptions of antimicrobial peptides (AMPs) genes regulated by Toll and IMD pathways. This research can lay the foundation for the study on the resistance of lepidopteran insects to pyriproxyfen and other juvenile hormone pesticides.

Synthesis and Enhanced Photocatalytic Activity of Black Porous Zr-doped TiO2 Monoliths

Jimin Du,Huiming Wang,Huijuan Chen,Menghe Yang,Xiaoling Lu,Hui Guo,Zhanmin Zhang,Tianwei Shang,Shujue Xu,Wenqi Li,Pianpian Wang,Imran Shakir 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.6

Black Porous Zr-doped TiO2 monoliths were successfully synthesized by a combined route including sol–gel method with polystyrene spheres as template followed by calcination at high temperature in the presence of oxygen. As-synthesized samples were then treated in hydrogen atmosphere at 500℃ for 6 h to obtain black Porous Zr-doped TiO2 monoliths. This as-synthesized black porous Zr-doped TiO2 composite showed relatively narrow bandgap compared to the pure anatase phase of TiO2, which may have its origin from the contributions from the Zr impurity and oxygen vacancies. The photocatalytic activity of the black porous Zr-doped TiO2 monolith was examined by carrying out the dye degradation on Rhodamine B under visible irradiation. Our experimental results indicate that black porous 0.9% Zr-doped TiO2 sample exhibits high photocatalytic activity with the photodecomposition of 95.25% under visible irradiation for 120 min.