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Fixed-time stabilization of output-constrained stochastic high-order nonlinear systems

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Science China(Information Sciences) 2024年第4期67卷 5-20页

作者： Ruiming XIE Shengyuan xu Nanjing University of Science and Technology School of Automation

In this study, the fixed-time stabilization problem of stochastic high-order nonlinear systems with output constraint and high-order and low-order nonlinearities is addressed. A new coordinate transformation is employed to directly convert output-constrained stochastic systems into an equivalent unconstrained *** fully extracting the characteristics of system nonlinearities and using the stochastic fixed-time stability theorem, a new design and analysis method is constructed to guarantee that the trivial solution of the closed-loop system is stochastically fixed-time stable while fulfilling the output constraint.

关键词： stochastic high-order nonlinear system outputconstraint high-order and low-order nonlinearity fixed-timestabilization finite-time stabilization

Deep learning based water leakage detection for shield tunnel lining

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Frontiers of Structural and Civil Engineering 2024年第6期18卷 887-898页

作者： Shichang LIU xu xu Gwanggil JEON Junxin CHEN Ben-Guo HE College of Computer Science Sichuan UniversityChengdu 610065China School of Computer Science and Engineering Northeastern UniversityShenyang 110004China Department of Embedded Systems Engineering Incheon National UniversityIncheon 22012Korea School of Software Dalian University of TechnologyDalian 116621China Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang 110819China

Shield tunnel lining is prone to water leakage,which may further bring about corrosion and structural damage to the walls,potentially leading to dangerous *** avoid tedious and inefficient manual inspection,many projects use artificial intelligence(Al)to detect cracks and water leakage.A novel method for water leakage inspection in shield tunnel lining that utilizes deep learning is introduced in this *** proposal includes a ConvNeXt-S backbone,deconvolutional-feature pyramid network(D-FPN),spatial attention module(SPAM).and a detection *** can extract representative features of leaking areas to aid inspection *** further improve the model's robustness,we innovatively use an inversed low-light enhancement method to convert normally illuminated images to low light ones and introduce them into the training *** experiments are performed,achieving the average precision(AP)score of 56.8%,which outperforms previous work by a margin of 5.7%.Visualization illustrations also support our method's practical effectiveness.

关键词： water leakage detection deep learning deconvolutional-feature pyramid spatial attention

Highly elastic 2D covalent organic framework films of interwoven single crystals

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National Science Review 2024年第7期11卷 71-72页

作者： Tongwen xu Key Laboratory of Precision and Intelligent Chemistry Department of Applied ChemistrySchool of Chemistry and Materials ScienceUniversity of Science and Technology of China

Two-dimensional(2D) materials feature angstrom-scale pores and tunable pore chemistry, demonstrating great potential for applications including flexible electronics and *** ion/molecule transport in the sub-nanometer-sized pore confinement often reveals phenomena not seen in bulk materials [1]. Yet, the practical application of 2D materials is hindered by their poor mechanical properties.

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Biohythane production from two-stage anaerobic digestion of food waste:A review

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Journal of Environmental Sciences 2024年第5期139卷 334-349页

作者： Xiaona An Ying xu Xiaohu Dai State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

The biotransformation of food waste(FW)to bioenergy has attracted considerable research attention as a means to address the energy crisis and waste disposal *** this end,a promising technique is two-stage anaerobic digestion(TSAD),in which the FW is transformed to biohythane,a gaseous mixture of biomethane and *** review summarises the main characteristics of FW and describes the basic principle of ***,the factors influencing the TSAD performance are identified,and an overview of the research status;economic aspects;and strategies such as pre-treatment,co-digestion,and regulation of microbial consortia to increase the biohythane yield from TSAD is ***,the challenges and future considerations associated with the treatment of FW by TSAD are *** paper can provide valuable reference for the improvement and widespread implementation of TSAD-based FW treatment.

关键词： Two-stage anaerobic digestion(TSAD) Food waste(FW) Methane production Hydrogen production

Comparison of Microwave Imaging Algorithms for Short-Range Scenarios

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Journal of Beijing Institute of Technology 2024年第3期33卷 227-236页

作者： Zhengyue Dong Ning xu Kuiwen xu Engineering Research Center of Smart Microsensors and Microsystems Ministry of EducationHangzhou Dianzi UniversityHangzhou 310018China

Three dimensional(3-D)imaging algorithms with irregular planar multiple-input-multiple-output(MIMO)arrays are discussed and compared with each *** on the same MIMO array,a modified back projection algorithm(MBPA)is accordingly proposed and four imaging algorithms are used for comparison,back-projection method(BP),back-projection one in time domain(BP-TD),modified back-projection one and fast Fourier transform(FFT)-based MIMO range migration algorithm(FFT-based MIMO RMA).All of the algorithms have been implemented in practical application scenarios by use of the proposed imaging *** to the practical applications,MIMO array-based imaging system with wide-bandwidth properties provides an efficient tool to detect objects hidden behind a *** MIMO imaging radar system,composed of a vector network analyzer(VNA),a set of switches,and an array of Vivaldi antennas,have been designed,fabricated,and ***,these algorithms have been applied to measured data collected in different scenarios constituted by five metallic spheres in the absence and in the presence of a wall between the antennas and the targets in simulation and pliers in free space for experimental ***,the focusing properties and time consumption of the above algorithms are compared.

关键词： multiple-input-multiple-output(MIMO) short-range imaging back projection modi-fied back propagation range migration algorithm(RMA) through-wall imaging

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全站仪建筑物立面图测量方法研究及工程实践

测绘地理信息 2017年第1期42卷 10-13页

作者：何屹雄花向红许承权姚周祥黎洋武汉大学测绘学院湖北武汉430079 武汉大学灾害监测和防治研究中心湖北武汉430079 闽江学院福建福州350108

立面图是城市建筑物外观装修和景观改造设计与施工中的重要依据。其投影面是与立面平行的铅垂面,但常见成图软件的投影面是水平面,因此无法直接用于立面图测绘。本文从立面测量的原理出发,介绍了基于全站仪和CASS成图软件的立面测量方法... 详细信息

立面图是城市建筑物外观装修和景观改造设计与施工中的重要依据。其投影面是与立面平行的铅垂面,但常见成图软件的投影面是水平面,因此无法直接用于立面图测绘。本文从立面测量的原理出发,介绍了基于全站仪和CASS成图软件的立面测量方法,阐述了立面测量坐标转换的方法,并对此方法做出了精度分析。

关键词：全站仪立面图测量精度分析坐标转换 CASS

Sharper Hardy Uncertainty Relations on Signal Concentration in Terms of Linear Canonical Transform

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Chinese Journal of Electronics 2024年第5期33卷 1317-1325页

作者： Xiaogang xu Guanlei xu Xiaotong WANG College of Computer and Information Engineering Zhejiang Gongshang University

Linear canonical transform is of much significance to optics and information science. Hardy uncertainty principle, like Heisenberg uncertainty principle, plays an important role in various fields. In this paper, four new sharper Hardy uncertainty relations on linear canonical transform are derived. These new derived uncertainty relations are connected with the linear canonical transform parameters and indicate new insights for signal energy ***, for certain transform parameters, e.g. b = 0, these new proposed uncertainty relations break the traditional counterparts in signal energy concentration, as will result in new physical interpretation in terms of uncertainty principle. Theoretical analysis and numerical examples are given to show the efficiency of these new relations.

关键词： Information science Uncertainty Transforms Optics Hardy uncertainty principle Linear canonical transform Signal concentration PRINCIPLE

A stable staggered-grid finite-difference scheme for acoustic modeling beyond conventional stability limit

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Petroleum Science 2024年第1期21卷 182-194页

作者： Jing-Yi xu Yang Liu National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing 102249China China University of Petroleum(Beijing) Karamay CampusKaramay 834000XinjiangChina

Staggered-grid finite-difference(SGFD)schemes have been widely used in acoustic wave modeling for geophysical *** improved methods are proposed to enhance the accuracy of numerical ***,these methods are inevitably limited by the maximum Courant-Friedrichs-Lewy(CFL)numbers,making them unstable when modeling with large time sampling intervals or small grid *** solve this problem,we extend a stable SGFD scheme by controlling SGFD dispersion relations and maximizing the maximum CFL ***,to improve modeling stability,we minimize the error between the FD dispersion relation and the exact relation in the given wave-number region,and make the FD dispersion approach a given function outside the given wave-number area,thus breaking the conventional limits of the maximum CFL ***,to obtain high modeling accuracy,we use the SGFD scheme based on the Remez algorithm to compute the FD *** addition,the hybrid absorbing boundary condition is adopted to suppress boundary reflections and we find a suitable weighting coefficient for the proposed *** derivation and numerical modeling demonstrate that the proposed scheme can maintain high accuracy in the modeling process and the value of the maximum CFL number of the proposed scheme can exceed that of the conventional SGFD scheme when adopting a small maximum effective wavenumber,indicating that the proposed scheme improves stability during the modeling.

关键词： Acoustic wave Staggered-grid finite-difference(SGFD) modeling Courant-friedrichs-lewy(CFL)number Stability

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建筑立面面积自动测算方法研究与算法实现

测绘地理信息 2022年第3期47卷 87-90页

作者：许承权吴永红张帆黄德华闽江学院地理与海洋学院福建福州350108 福建省测绘院福建福州350100 福建省地质测绘院福建福州350100

利用传统人工方法计算、汇总建筑立面面积费时、费力,不能满足高效决策支持、工程决算的需要。针对此问题,采用Visual Basic for Applications(VBA)开发方式,基于建筑立面改造区域已有的数字地形图,通过获取区域内所有房屋及其附属物的C... 详细信息

利用传统人工方法计算、汇总建筑立面面积费时、费力,不能满足高效决策支持、工程决算的需要。针对此问题,采用Visual Basic for Applications(VBA)开发方式,基于建筑立面改造区域已有的数字地形图,通过获取区域内所有房屋及其附属物的CASS扩展属性、结构注记、层数注记和基底周长等信息,自动计算、汇总建筑立面面积,达到立面测绘工作量快速估算的目标,为科学决策提供依据;基于批量立面测绘成果,通过行列边界搜索算法,自动搜索立面边界,并计算、汇总出精确的立面测绘工作量,实现立面测绘工作量的自动精算,为工程决算提供依据。

关键词：建筑立面 AutoCAD二次开发 CASS扩展属性行列搜索算法