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IEEE Conference on Decision and Control

作者： Ben Liu Hua Chen Wei Zhang Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and Technology Shenzhen China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

In this paper, we focus on state estimation problem for nonlinear systems on joint matrix Lie group and Euclidean space We propose a general iterative Kalman filter, aiming to integrate the prediction step into the iteration scheme, which is not considered in the conventional iterative extended Kalman filter framework. Such an extra iteration scheme in the prediction step helps improving the accuracy of probability density function propagation through nonlinearities, which can further lead to more accurate estimations of the system states. In addition, the proposed framework unifies the Kalman filter based estimation schemes on studied manifold by adopting the perspective from Gaussian Bayesian inference. The improvement of the proposed framework is illustrated by the ES-GIKF algorithm that is instantiated from the proposed framework in a numerical simulation.

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Natural antibacterial membranes prepared using Schisandra chinensis extracts and polyvinyl alcohol in an environment-friendly manner

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Chemosphere 2024年 346卷 140524页

作者： Jia, Wenting Jiang, Shanxue Wang, Fang Li, Jing Wang, Zeru Yao, Zhiliang School of Ecology and Environment Beijing Technology and Business University Beijing100048 China State Environmental Protection Key Laboratory of Food Chain Pollution Control Beijing Technology and Business University Beijing100048 China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China

Foodborne pathogens can cause food spoilage and lead to food safety issues. In recent years, food packaging has received a lot of attention. Traditional packaging membranes are non-biodegradable and remain in the environment for a long time. In this study, natural antimicrobial substances were extracted from Schisandra chinensis by a green extraction process using distilled water as the solvent, and the effects of different treatment on the antimicrobial activity of the extract were compared. At the same time, four types of Schisandra chinensis antimicrobial membranes were prepared using polyvinyl alcohol (PVA) as the substrate. The whole extraction and membrane preparation process did not involve organic solvents, making the process green and environment friendly. Material characterization included inverted biological microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), tensile strength test, pore size measurement, water uptake test, etc. Among them, no extract particles were observed with the naked eye on the surfaces of MⅡ and MⅣ. MⅡ has a uniformly transparent, nearly colorless morphology and is the most tensile. MⅣ surface is flat and smooth, the microstructure is dense and uniform. At the same time, the four types of membranes were tested against common pathogenic bacteria for 12 h, and the OD600 trend revealed the excellent antimicrobial activity of the membranes against S. aureus, MRSA, E. coli, and L. monocytogenes. The membranes could also be reused at least once. This study provides a new idea for preparing natural plant-based antimicrobial membranes. © 2023 Elsevier Ltd

关键词： Food safety

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Research on Optimization of Momentum Source Model to Supercritical Carbon Dioxide Flow in Wire Wrapped Rods Bundle

SSRN

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SSRN 2023年

作者： Liu, Sichao Liu, Yu Yang, Xiaolei Li, Xiaochang Tian, Ruifeng College of Nuclear Science and Technology Harbin Engineering University Harbin150001 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu601213 China College of Aerospace and Civil Engineering Harbin Engineering University Harbin150001 China

Wrapped wire is widely used in new reactor core design. Simulation with traditional body fitted grid needs a large number of grids, which requires more computing resources. By optimizing the basic mathematical model of momentum source method, simulation of wire wrapped rod bundle with arbitrary wire shape can be carried out. By simulating the experimental data of 3 wire wrapped rod bundle, the model adaptability of momentum source method and mesh sensitivity analysis are carried out. Then optimized momentum source method and original momentum source method are compared based on simulation of supercritical carbon dioxide flow and heat transfer in wire wrapped rod bundle with different wire shapes. Through comparison with body fitted grid, the improvement of accuracy of optimized momentum source model can be proved. In conclusion, optimized momentum source method can greatly save the computational resources and calculated results is more accurate than original momentum source method. © 2023, The Authors. All rights reserved.

关键词： Wire

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Propagation Characteristics of End-Winding Insulation Fatigue Damage in Variable Frequency Motor Under Multi-Field Coupling

Propagation Characteristics of End-Winding Insulation Fatigu...

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IEEE Conference on Electromagnetic Field Computation

作者： Bangwei Zhang Haijun Zhang Jiashun Wang Yuxin Cao Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Hubei university of Arts and Science Xiangyang China School of Electronic Information Engineering Taiyuan University of Science and Technology Taiyuan China

ISBN: (数字)9798350348958

ISBN: (纸本)9798350348965

In this paper, the fatigue propagation mechanism of motor stator insulation damage under variable frequency drive is studied by combining theoretical analysis and finite element numerical simulation. Based on the magneto-thermo-solid coupling and fatigue damage theory, the stress-strain state, crack damage degree and propagation rate of motor stator insulation are analyzed. The crack damage propagation at different positions of the end winding outlet, middle and nose end is simulated and calculated by three-dimensional finite element method. It is found that the stress, strain and stress intensity factor of the end winding insulation at the outlet position change violently, which reflects that the crack damage is easier to expand and the propagation rate is greater. The results of this paper can provide reference for the evolution law, fault diagnosis and optimization design of insulation damage of variable frequency drive motor under complex working conditions.

关键词： Couplings Insulation Windings Stator windings Variable speed drives Motors Fatigue

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Elusive isolating frequency of a locally resonant mechanical meta-layer

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Physical Review B 2023年第14期108卷 L140303-L140303页

作者： Yunhao Zhang Hao Zhou Yongquan Liu State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace Engineering Xi'an Jiaotong University Xi'an 710049 China Beijing Institute of Spacecraft System Engineering China Academy of Space Technology Beijing 100094 China National Key Laboratory of Science and Technology on Liquid Rocket Engines Xi'an 710100 China

In this work, we report a meta-layer consisting of subwavelength local resonators to achieve low-frequency isolation of elastic waves. Apart from its distinctive low-dimensional configuration with a thickness of 17 the wavelength, the meta-layer differs from bandgap-based metamaterials in that its optimally isolating frequency is higher than the eigenfrequency. We demonstrate theoretically, numerically, and experimentally that the isolating frequency shift arises from the coupling effect between the resonators and the load-carrying plate or beam. As a further step, to demonstrate the universality of our theory, we predict and design a meta-layer with an opposite-frequency shift. The proposed meta-layer, along with its corresponding theory, can precisely guide the development of compact low-frequency wave isolation devices.

关键词： Elastic waves Mechanical & acoustical properties Metamaterials

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High-order Fully Actuated Approach for Output Position Control of Two Mass systems based on Extended State Observer

High-order Fully Actuated Approach for Output Position Contr...

引用

Fully Actuated system Theory and Applications (CFASTA), Conference on

作者： Ping Li Guang-Ren Duan Bi Zhang Yuzhong Wang Shenzhen Key Laboratory of Control Theory and Intelligent Systems School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China Center for Control Theory and Guidance Technology Harbin Institute of Technology Harbin China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen China

ISBN: (数字)9798350373691

ISBN: (纸本)9798350373707

This paper proposes a high-order fully actuated (HOFA) control approach for the output position control of two-mass systems (TMSs) based on extended state observer (ESO). TMSs belongs to a class of underactuated mechanical systems, which can be converted into an HOFA model using variable elimination. Based on the feature of HOFA model, it is extremely simple to solve the position control law such that a desired tracking error system can be achieved. To handle the control issues of high-order derivatives and unknown disturbances, a linear ESO is employed for state estimation and active disturbance rejection control, where the lumped disturbance is treated as an extended system state. The theoretical stability of control system is analyzed with the help of sliding manifold. Comparative simulations are performed to demonstrate the effectiveness of the proposed approach.

关键词： Robust control Uncertain systems Simulation Position control Observers Control systems Stability analysis

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FAGC: Free Space Fragmentation Aware GC Scheme based on Observations of Energy Consumption

FAGC: Free Space Fragmentation Aware GC Scheme based on Obse...

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design, Automation and Test in Europe Conference and Exhibition

作者： Lihua Yang Zhipeng Tan Fang Wang Yang Xiao Wei Zhang Biao He Wuhan National Laboratory for Optoelectronics Key Laboratory of Information Storage System Engineering Research Center of Data Storage Systems and Technology Ministry of Education of China School of Computer Science and Technology Huazhong University of Science and Technology College of Science and Technology National University of Defense Technology China Huawei Technology Co. Ltd China

Smartphones are everyday necessities with limited power supply. Charging a smartphone twice a day or more affects user experience. Flash friendly file system (F2FS) is a widely-used log-structured file system for smartphones. Free space fragmentation of F2FS consists of invalid blocks mainly causing performance degradation. F2FS reclaims invalid blocks by garbage collection (GC). We explore the energy consumption of GC and the effect of GC on reducing free space fragments. We observe the energy consumption of one background GC is large but its effect on reducing free space fragments is limited. These motivate us to improve the energy efficiency of GC. We reassess how much free space is a free space fragment based on data analysis, use the free space fragmentation factor to measure the degree of free space fragmentation quickly. We suggest the free space fragmentation aware GC scheme (FAGC) that optimizes the selection for victim segments and the migration for valid blocks. Experiments on real platform show that FAGC reduces GC count by 82.68% and 74.51% respectively than traditional F2FS and the latest GC optimization of F2FS, ATGC. FAGC reduces the energy consumption by 164.37 J and 100.64 J compared to traditional F2FS and ATGC respectively for a synthetic benchmark.

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Quantifying 3D cell-matrix interactions during mitosis and the effect of anticancer drugs on the interactions

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Nano Research 2021年第11期14卷 4163-4172页

作者： Yongman Liu Jianye Wang Yong Su Xiaohai Xu Hong Liu Kainan Mei Shihai Lan Shubo Zhang Xiaoping Wu Yunxia Cao Qingchuan Zhang Shangquan Wu CAS Key Laboratory of Mechanical Behavior and Design of Material Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of ChinaHefei230027China Reproductive Medicine Center Department of Obstetrics and GynecologyThe First Affiliated Hospital of Anhui Medical UniversityHefei230022China Anhui Province Key Laboratory of Reproductive Health and Genetics Anhui Medical UniversityHefei230022China Department of Chemical Physics University of Science and Technology of ChinaHefei230026China

The mechanical force between cells and the extracellular microenvironment is crucial to many physiological processes such as cancer metastasis and stem cell differentiation. Mitosis plays an essential role in all these processes and thus an in-depth understanding of forces during mitosis gains insight into disease diagnosis and disease treatment. Here, we develop a traction force microscope method based on monolayer fluorescent beads for measuring the weak traction force (tens of Pa) of mitotic cells in three dimensions. We quantify traction forces of human ovarian granulosa (KGN) cells exerted on the extracellular matrix throughout the entire cell cycle in three dimensions. Our measurements reveal how forces vary during the cell cycle, especially during cell division. Furthermore, we study the effect of paclitaxel (PTX) and nocodazole (NDZ) on mitotic KGN cells through the measurement of traction forces. Our results show that mitotic cells with high concentrations of PTX exert a larger force than those with high concentrations of NDZ, which proved to be caused by changes in the structure and number of microtubules. These findings reveal the key functions of microtubule in generating traction forces during cell mitosis and explain how dividing cells regulate themselves in response to anti-mitosis drugs. This work provides a powerful tool for investigating cell-matrix interactions during mitosis and may offer a potential way to new therapies for cancer.

关键词： cell division traction force paclitaxel nocodazole

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Parameter effects on high-speed UAV ground directional stability using bifurcation analysis

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Chinese Journal of Aeronautics 2021年第11期34卷 1-14页

作者： Qiaozhi YIN Xiaohui WEI Hong NIE Jian DENG State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and AstronauticsNanjing 210016China MIIT Key Laboratory of Multifunctional Lightweight Materials and Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A loss of ground directional stability can trigger a high-speed Unmanned Aerial Vehicle(UAV)to veer off the *** order to investigate the combined effects of the key structural and operational parameters on the UAV ground directional stability from a global perspective,a fully parameterized mathematical high-speed UAV ground nonlinear dynamic model is developed considering several nonlinear *** bifurcation analysis procedure of a UAV ground steering system is introduced,following which the simulation efficiency is greatly improved comparing with the time-domain simulation *** the numerical continuation method is employed to investigate the influence of the nose wheel steering angle and the global stability region is *** bifurcation parameter plane is divided into several parts with different stability properties by the saddle nodes and the Hopf bifurcation *** find that the UAV motion states will never cross the bifurcation curve in the nonlinear ***,the dual-parameter bifurcation analyses are presented to give a complete description of the possible steering *** is also found that BT bifurcation appears when the UAV initial rectilinear velocity and the tire frictional coefficient *** addition,results indicate that the influence of tire frictional coefficient has an opposite trend to the influence of initial rectilinear ***,using bifurcation analysis method to identify the parameter regions of a UAV nonlinear ground dynamic system helps to improve the development efficiency and quality during UAV designing phase.

关键词： Bifurcation analysis Ground directional stability High-speed UAV Nonlinear system Numerical continuation

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DarkSAM: Fooling Segment Anything Model to Segment Nothing

arXiv

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arXiv 2024年

作者： Zhou, Ziqi Song, Yufei Li, Minghui Hu, Shengshan Wang, Xianlong Zhang, Leo Yu Yao, Dezhong Jin, Hai National Engineering Research Center for Big Data Technology and System China Services Computing Technology and System Lab China Cluster and Grid Computing Lab China Hubei Engineering Research Center on Big Data Security China Hubei Key Laboratory of Distributed System Security China School of Cyber Science and Engineering Huazhong University of Science and Technology China School of Software Engineering Huazhong University of Science and Technology China School of Information and Communication Technology Griffith University Australia

Segment Anything Model (SAM) has recently gained much attention for its outstanding generalization to unseen data and tasks. Despite its promising prospect, the vulnerabilities of SAM, especially to universal adversarial perturbation (UAP) have not been thoroughly investigated yet. In this paper, we propose DarkSAM, the first prompt-free universal attack framework against SAM, including a semantic decoupling-based spatial attack and a texture distortion-based frequency attack. We first divide the output of SAM into foreground and background. Then, we design a shadow target strategy to obtain the semantic blueprint of the image as the attack target. DarkSAM is dedicated to fooling SAM by extracting and destroying crucial object features from images in both spatial and frequency domains. In the spatial domain, we disrupt the semantics of both the foreground and background in the image to confuse SAM. In the frequency domain, we further enhance the attack effectiveness by distorting the high-frequency components (i.e., texture information) of the image. Consequently, with a single UAP, DarkSAM renders SAM incapable of segmenting objects across diverse images with varying prompts. Experimental results on four datasets for SAM and its two variant models demonstrate the powerful attack capability and transferability of DarkSAM. Our codes are available at: https://***/CGCL-codes/DarkSAM. Copyright © 2024, The Authors. All rights reserved.

关键词： Frequency domain analysis

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