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Comparative Analysis of ARIMA and LSTM Model-Based Anomaly detection for Unannotated Structural Health Monitoring Data in an Immersed Tunnel

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1797-1827页

作者： Qing Ai Hao Tian Hui Wang Qing Lang Xingchun Huang Xinghong Jiang Qiang Jing School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China key laboratory of road and bridge detection and maintenance technology of zhejiang province Hangzhou311305China zhejiang Scientific Research Institute of Transport Hangzhou310023China State key laboratory of Coal Mine Dynamics and Control Chongqing UniversityChongqing400044China Hong Kong-Zhuhai-Macao bridge Authority Zhuhai519060China

Structural Health Monitoring(SHM)systems have become a crucial tool for the operational management of long *** immersed tunnels exposed to both traffic loads and the effects of the marine environment,efficiently identifying abnormal conditions from the extensive unannotated SHM data presents a significant *** study proposed amodel-based approach for anomaly detection and conducted validation and comparative analysis of two distinct temporal predictive models using SHM data from a real immersed ***,a dynamic predictive model-based anomaly detectionmethod is proposed,which utilizes a rolling time window for modeling to achieve dynamic *** the assumption of temporal data similarity,an interval prediction value deviation was employed to determine the abnormality of the ***,dynamic predictive models were constructed based on the Autoregressive Integrated Moving Average(ARIMA)and Long Short-Term Memory(LSTM)*** hyperparameters of these models were optimized and selected using monitoring data from the immersed tunnel,yielding viable static and dynamic predictive ***,the models were applied within the same segment of SHM data,to validate the effectiveness of the anomaly detection approach based on dynamic predictive modeling.A detailed comparative analysis discusses the discrepancies in temporal anomaly detection between the ARIMA-and LSTM-based *** results demonstrated that the dynamic predictive modelbased anomaly detection approach was effective for dealing with unannotated SHM *** a comparison between ARIMA and LSTM,it was found that ARIMA demonstrated higher modeling efficiency,rendering it suitable for short-term *** contrast,the LSTM model exhibited greater capacity to capture long-term performance trends and enhanced early warning capabilities,thereby resulting in superior overall performance.

关键词： Anomaly detection dynamic predictive model structural health monitoring immersed tunnel LSTM ARIMA

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Dynamical nonlinear excitations induced by interaction quench in a two-dimensional box-trapped Bose-Einstein condensate

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Chinese Physics B 2024年第2期33卷 209-215页

作者：牛真霞高超 Department of Physics Zhejiang Normal UniversityJinhua 321004China key laboratory of Optical Information detection and Display technology of zhejiang Zhejiang Normal UniversityJinhua 321004China

Manipulating nonlinear excitations,including solitons and vortices,is an essential topic in quantum many-body physics.A new progress in this direction is a protocol proposed in[***.2043256(2020)]to produce dark solitons in a one-dimensional atomic Bose–Einstein condensate(BEC)by quenching inter-atomic *** by this work,we generalize the protocol to a two-dimensional BEC and investigate the generic scenario of its post-quench *** an isotropic disk trap with a hard-wall boundary,we find that successive inward-moving ring dark solitons(RDSs)can be induced from the edge,and the number of RDSs can be controlled by tuning the ratio of the after-and before-quench interaction strength across different critical *** role of the quench played on the profiles of the density,phase,and sound velocity is also *** to the snake instability,the RDSs then become vortex–antivortex pairs with peculiar dynamics managed by the initial density and the after-quench *** tuning the geometry of the box traps,demonstrated as polygonal ones,more subtle dynamics of solitons and vortices are *** proposed protocol and the discovered rich dynamical effects on nonlinear excitations can be realized in near future cold-atom experiments.

关键词： Bose-Einstein condensate quench interaction soliton vortex

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A feedback control method for phase signal demodulation in fber-optic hydrophones

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 515-528页

作者： Zhiqiang LIU Lei XIA Qiangfeng LYU Bin WU Ronghua HUAN Zhilong HUANG Department of Mechanics Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceZhejiang UniversityHangzhou 310000China Huanjiang laboratory Zhuji 311899Zhejiang ProvinceChina Advanced technology Research Institute Zhejiang UniversityHangzhou 310000China

In the realm of acoustic signal detection,the identification of weak signals,particularly in the presence of negative signal-to-noise ratios,poses a significant *** challenge is further heightened when signals are acquired through fiber-optic hydrophones,as these signals often lack physical significance and resist clear systematic *** processing methods,e.g.,low-pass filter(LPF),require a thorough understanding of the effective signal bandwidth for noise reduction,and may introduce undesirable time *** paper introduces an innovative feedback control method with dual Kalman filters for the demodulation of phase signals with noises in fiber-optic hydrophones.A mathematical model of the closed-loop system is established to guide the design of the feedback control,aiming to achieve a balance with the input phase *** dual Kalman filters are instrumental in mitigating the effects of signal noise,observation noise,and control execution noise,thereby enabling precise estimation for the input phase *** effectiveness of this feedback control method is demonstrated through examples,showcasing the restoration of low-noise signals,negative signal-to-noise ratio signals,and multi-frequency *** research contributes to the technical advancement of high-performance devices,including fiber-optic hydrophones and phase-locked amplifiers.

关键词： feedback control method fiber-optic hydrophone acoustic signal detection phase signal

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High-performance wearable bimetallic nanowire-assisted composite foams for efficient electromagnetic interference shielding,infrared stealth,and piezoresistive sensing

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Nano Research 2024年第7期17卷 6757-6765页

作者： Tianyi Hang Lijie Zhou Chenhui Xu Yiming Chen Jiahui Shen Jiajia Zheng Pingan Yang Xiping Li Heng Luo Guoxiu Tong key laboratory of Urban Rail Transit Intelligent Operation and maintenance technology and Equipment of zhejiang province College of EngineeringZhejiang Normal UniversityJinhua 321004China School of Automation Chongqing University of Posts and TelecommunicationsChongqing 400065China State key laboratory of Powder Metallurgy Central South UniversityChangsha 410083China key laboratory of the Ministry of Education for Advanced Catalysis Materials College of Chemistry and Materials ScienceZhejiang Normal UniversityJinhua 321004China

With the accelerated development of modern detection and communication technology,the multifunctional wearable materials with excellent electromagnetic interference(EMI)shielding,infrared stealth,and human monitoring for improving military combat capability have received extensive *** this work,the lightweight melamine foam(MF)@silver nanowires(AgNWs)-iron nanowires(FeNWs)(AgFe-MF)was fabricated by a vacuum-assisted dip-coating *** to the porous structure and synergistic electrical and magnetic losses,this lightweight(0.115 g/cm^(3))composite foam with an ultra-low filler content(0.62 vol.%)exhibited an ideal EMI shielding efficiency of 38.4 *** the other hand,the AgFe-MF realized a powerful multifunctional *** surface saturation temperature of the AgFe-MF reached 94.2℃under a low applied voltage of 1.8 V and remained extremely fast heating and cooling response and terrific working stability,resulting in excellent infrared stealth and camouflage ***,taking virtues of the elastic porous conductive architecture,the AgFe-MF was utilized as a piezoresistive sensor exhibiting board compressive interval of 0–1.62 kPa(50%strain)with a good sensitivity of 0.57 kPa−*** work will provide new ideas and insights for developing multifunctional wearable devices in the fields of EMI shielding,thermal management,and piezoresistive sensing.

关键词： metal nanowires porous foams electromagnetic interference shielding infrared stealth wearable sensors

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A comparative investigation on wear behaviors of physical and chemical vapor deposited bronze coatings for hydraulic piston pump

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Chinese Journal of Aeronautics 2024年第3期37卷 391-403页

作者： Wei HAO Andrews LARBI Hongkang DONG Dongyun WANG Shenghu LI zhejiang Provincial key laboratory of Urban Rail Transit Intelligent Operation and maintenance technology and Equipment Zhejiang Normal UniversityJinhua 321004China College of Engineering Zhejiang Normal UniversityJinhua 321004China Hangzhou Lilong Hydraulic Co. LtdHangzhou 311200China

The cylinder block/valve plate interface is one of the most critical frictional interfaces of the swashplate-type axial piston ***,the poor lubrication interface caused rapid wear and high friction loss in an elastohydrodynamic lubrication system,decreasing the pump *** resistant bronze coatings were fabricated on 38CrMoAl substrate by Physical Vapor Deposition(PVD)and Chemical Vapor Deposition(CVD),***-on-disc wear tests were performed to comparatively investigate the wear behaviors of the coatings and bulk ductile iron *** can be found that the PVD-bronze coating exhibited better wear resistance than the other two *** enhanced wear resistance was attributed to the unique composite microstructure and desired mechanical strength,which could resist to mechanical shear and spallation,decreasing friction *** appropriate hardness of(1.33±0.07)GPa could be beneficial for enhancing its wear *** PVD-bronze coating possessed a much lower and stable coefficient of friction(about 0.1)and wear rate(about 6000μm3.N-1.m-1)under the loading forces of about 100 N after 20 *** wear mechanism was the abrasive wear.

关键词： Aircraft hydraulic pump Bronze Coatings Wear resistance Mechanisms

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DMT:A model detecting multispecies of tea buds in multi-seasons

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 199-208页

作者： Taojie Yu Jianneng Chen Zhiwei Chen Yatao Li Junhua Tong Xiaoqiang Du School of Mechanical Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China key laboratory of Transplanting Equipment and technology of zhejiang province Hangzhou 310018China

In China,tea products made from fresh leaves characterized by one leaf with one bud(1L1B)are classified as“Famous Tea”,which has better taste and higher economic value,but suffers from a labor *** at picking automation,existing studies focus on visual detection of 1L1B,but algorithm validation is limited to a specific variety of tea sprouting in a certain harvest season at a certain location,which limits the engineering application of developed tea picking robots working in various natural tea *** address this gap,a deep learning model DMT(detecting multispecies of tea)based on YOLOX-S was proposed in this *** DMT network takes YOLOX-S as a baseline and adds ECA-Net to the CSP Darknet and FPN of *** average precision(AP),precision,and recall of DMT are 94.23%,93.39%,and 88.02%,respectively,for detecting 1L1B sprouting in spring;93.92%,93.56%,and 87.88%,respectively,for detecting 1L1Bsprouting in *** experimental results are better than those of the five current object detection *** fine-tuning the DMT network with another dataset composed of multiple tea varieties,the DMT network can detect 1L1B for different varieties of tea in multiple picking *** results can promote the engineering application of picking automation of fresh tea leaves.

关键词： tea buds detection model multispecies of tea multi-season

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Topological phases and edge modes of an uneven ladder

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Chinese Physics B 2024年第8期33卷 154-168页

作者：商文创韩熠宁 Shimpei Endo 高超 Department of Physics Zhejiang Normal UniversityJinhua 321004China key laboratory of Optical Information detection and Display technology of zhejiang Zhejiang Normal UniversityJinhua 321004China Department of Engineering Science The University of Electro-CommunicationsTokyo 182-8585Japan

We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of *** an uneven ladder presents rich band structures classified by the closure of either direct or indirect *** also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge *** also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band ***,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the *** this way,the topological phases can be efficiently extracted through winding *** propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.

关键词： ladder model symmetry-protected topological phase topological invariant bulk-boundary correspondence

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Toughened (Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composites fabricated by one-step reactive sintering with a unique SiB_(6) additive

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Journal of Advanced Ceramics 2024年第1期13卷 86-100页

作者： Wei Hao Xinzhe Lu Ling Li Tao Wang Guoliang Ren Huangyue Cai Xiaofeng Zhao Dongyun Wang Na Ni zhejiang Provincial key laboratory of Urban Rail Transit Intelligent Operation and maintenance technology&Equipment Zhejiang Normal UniversityZhejiang 321004China key Lab of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

High-entropy diboride has been arousing considerable interest in recent ***,the low toughness and damage tolerance limit its applications as ultra-high-temperature structural *** we report that a unique SiB_(6) additive has been first incorporated as boron and silicon sources to fabricate a high-entropy boride(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composite though one-step boro/carbothermal reduction reactive sintering.A synergetic effect of high-entropy sluggish diffusion and SiC secondary phase retarded the grain growth of the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–51SiC *** small grain size was beneficial to shorten the diffusion path for mass transport,thereby enhancing the relative density to~99.3%.These results in an increase of fracture toughness from~5.2 in HEBS-1900 to~7.7 MPa·m^(1/2) in HEBS-2000,which corresponded to a large improvement of 48%.The improvement was attributed to a mixed mode of intergranular and transgranular cracking for offering effective pinning in crack propagation,resulting from balanced grain boundary strength collectively affected by improved densification,solid solution strengthening,and incorporation of SiC secondary phase.

关键词： high-entropy diboride silicon hexaboride boro/carbothermal reduction reactive sintering fracture toughness

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Generative pre-trained transformers(GPT)-based automated data mining for building energy management:Advantages,limitations and the future

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Energy and Built Environment 2024年第1期5卷 143-169页

作者： Chaobo Zhang Jie Lu Yang Zhao Institute of Refrigeration and Cryogenics Zhejiang UniversityHangzhouChina Department of the Built Environment Eindhoven University of TechnologyEindhovenThe Netherlands key laboratory of Clean Energy and Carbon Neutrality of zhejiang province Jiaxing Research InstituteZhejiang UniversityJiaxingChina

Advanced data mining methods have shown a promising capacity in building energy ***,in the past decade,such methods are rarely applied in practice,since they highly rely on users to customize solutions according to the characteristics of target building energy ***,the major barrier is that the practical applications of such methods remain *** is necessary to enable computers to have the human-like ability to solve data mining *** pre-trained transformers(GPT)might be capable of addressing this issue,as some GPT models such as GPT-3.5 and GPT-4 have shown powerful abilities on interaction with humans,code generation,and inference with common sense and domain *** study explores the potential of the most advanced GPT model(GPT-4)in three data mining scenarios of building energy management,i.e.,energy load prediction,fault diagnosis,and anomaly detection.A performance evaluation framework is proposed to verify the capabilities of GPT-4 on generating energy load prediction codes,diagnosing device faults,and detecting abnormal system operation *** is demonstrated that GPT-4 can automatically solve most of the data mining tasks in this domain,which overcomes the barrier of practical applications of data mining methods in this *** the exploration of GPT-4,its advantages and limitations are also discussed comprehensively for revealing future research directions in this domain.

关键词： ChatGPT GPT-4 Artificial general intelligence Data mining Building energy management

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Linear instability of hairy black holes in Horndeski theory

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Chinese Physics C 2024年第7期48卷 253-258页

作者：张超朱涛 Beijing key laboratory of Optical detection technology for Oil and Gas Basic Research Center for Energy InterdisciplinaryCollege of ScienceChina University of Petroleum-BeijingBeijing 102249China Institute for Theoretical Physics and Cosmology Zhejiang University of TechnologyHangzhou 310023China United Center for Gravitational Wave Physics(UCGWP) Zhejiang University of TechnologyHangzhou 310023China

Horndeski theory constitutes the most general model of scalar-tensor *** has attracted much attention in recent years in relation with black holes,celestial dynamics,stability analysis,*** is important to note that,for certain subclasses of Horndeski models,one can obtain analytic solutions for the background *** facilitates the investigation of the corresponding stability problems in *** particular,we aim to determine the constraints to the model or theory under which the stability conditions can be *** this study,we focused on a subclass of Horndeski theory and a set of analytic background *** addition,the odd-parity gravitational perturbation and 2nd-order Lagrangian were *** careful analysis,the instability was identified within the neighborhood of the event *** allows exclusion of a specific geometry for the *** an instability is implanted in the structure of the corresponding Lagrangian and is not erased by simply adding numerical constraints on the coupling *** a starting point of our research,the current study provides insights for further exploration of the Horndeski theory.

关键词： black holes black hole perturbations scalar-tensor theories Horndeski theory

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