Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the m...Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the main contributions is proving this property using linear algebra instead of profound knowledge.This makes it easy to read and understand this fundamental fact.The proof of linear independence of a set of Gauss functions relies on the constructing method for one-dimensional space and on the deducing method for higher dimensions.Additionally,under the condition of preserving the same moments between the original function and interpolating function,both the interpolating existence and uniqueness are proven for GRBF in one-dimensional space.The final work demonstrates the application of the GRBF method to locate lunar olivine.By combining preprocessed data using GRBF with the removing envelope curve method,a program is created to find the position of lunar olivine based on spectrum data,and the numerical experiment shows that it is an effective scheme.展开更多
A fast and accurate homography matrix method for four-wheel positioning detection was presented in the paper.Fewer sensors were required with simpler operation and faster detection.Firstly,eight feature points were ex...A fast and accurate homography matrix method for four-wheel positioning detection was presented in the paper.Fewer sensors were required with simpler operation and faster detection.Firstly,eight feature points were extracted by using the target detection algorithm based on the fitting method.Secondly,six feature points were obtained by line fitting-based selection.Thirdly,from the selected six feature points,five points were randomly chosen to minimize the re-projection error.Finally,four points were randomly selected from these five feature points to find the homography matrix,and the other point was back to the homography matrix for verification.The experimental results show that the mean re-projection error is reduced by about 3.41%−4.57%compared with the modified RANSAC(Random sample consensus)algorithm.With the optimized algorithm,the error is reduced by about 12.81%−13.86%compared with the improved RANSAC algorithm.Compared with traditional targets,the average calibration time is reduced by about 26.95%−27.88%.The results indicated that the combination of target algorithm and optimization algorithm could ensure the accuracy and reliability of four-wheel positioning.展开更多
The ratio of the pressure drop force to the drag force,C_(P),is concerned for a non-closely fitting spherical particle settling along the central line in long rectangular tubes with different A_(r)(A_(r)is W/H,where W...The ratio of the pressure drop force to the drag force,C_(P),is concerned for a non-closely fitting spherical particle settling along the central line in long rectangular tubes with different A_(r)(A_(r)is W/H,where W,H is length of the longer and shorter side of the rectangle respectively).Under Stokes flow conditions,C_(P0)for an infinitely small sphere in long rectangular tubes and C_(P)for a sphere in a long channel between two parallel layered barriers are both calculated.Then C_(P)of a sphere settling in long rectangular tubes are conducted with the direct-forcing fictitious domain(DF/FD)method.At large Reynolds number,the sphere settles unstably with a fluctuating velocity and C_(P).The fluctuation of Cp is much stronger than that of velocity and both fluctuations are stronger for less confined sphere.The influences of the particle Reynolds number(Re_(p))on C_(P)is similar to the existing experimental results in long circular tubes.At low Re_(p),C_(P)is a determined value and is calculated.For a given d/H(d sphere diameter),Cp gets its maximum value at one A_(r)in the range of[1,1.5].For a given A_(r),C_(P)is a quadratic function of d/H similar to that in a circular tube,and parameters of the quadratic function are got by curve fitting from numerical data.The constant term coefficients got have almost no difference with C_(P0)and are furtherly replaced by the latter to get new quadratic coefficients C_(P1).Lastly,an algebraic correlation of C_(P1)to A_(r)is developed.The predictions of Cp are good with a maximum relative error about 1.5%for a sphere with d/H not greater than0.7,compared to numerical results.展开更多
As seismic signals propagate underground,the subsurface media absorb high-frequency components,decreasing seismic resolution and limiting the identification and characterization of thin reservoirs.To address the limit...As seismic signals propagate underground,the subsurface media absorb high-frequency components,decreasing seismic resolution and limiting the identification and characterization of thin reservoirs.To address the limitation,this paper proposes a multichannel spectral fitting(MSF)method.The MSF method aims to enhance seismic resolution by considering the spectral characteristics and the correlations between adjacent seismic traces.The key to the MSF method involves utilizing the amplitude spectrum of the attenuated Ricker wavelet to construct an objective function for spectral fitting,leading to improved seismic resolution.Furthermore,the MSF method establishes the correlation between adjacent seismic traces as a constraint to stably solve the target parameters based on the entire seismic spectrum,which helps obtain horizontally consistent and more realistic seismic signals.Synthetic and field seismic examples demonstrate that the proposed method not only provides higher-resolution seismic signals but also reveals more fine details of thin reservoirs compared to the time-variant spectral whitening method.It is concluded that the MSF method is a promising tool for seismic signal processing.展开更多
Indigenous microbial communities were employed after subculture in stirred and column bioleaching experiments involving ion-adsorption type rare earth ore.The microbial eukaryotic communities exhibited dramatically va...Indigenous microbial communities were employed after subculture in stirred and column bioleaching experiments involving ion-adsorption type rare earth ore.The microbial eukaryotic communities exhibited dramatically varying diversity and structure across culture compositions.Compared with Czapek and sucrose medium,the community cultured in a nutrient broth(NB)medium had a high-er diversity,and it was mainly composed of Zygosaccharomyces,Ustilago,Kodamaea,Malassezia,and Aspergillus.These microorgan-isms secrete organic acids,such as citric acid,malic acid,gluconic acid,and itaconic acid,which provide effective coordination electrons through hydroxyl and carboxyl groups.Stirred bioleaching experiments were conducted to investigate the effect of community,inoculum dosage,liquid–solid ratio,and time on the leaching efficiency.Stirred bioleaching resulted in a concentration limitation phenomenon.When the inoculum dosage of the community cultured in NB medium was 70vol%,the liquid–solid ratio was 5.0 mL·g^(-1),and the time was 60 min,the upward trend of rare earths leaching rate has become very small.Specifically,the leaching rates of detectable La,Ce,and Y were approximately 92.49%,92.42%,and 94.39%,respectively.The leaching efficiency and the three influencing factors all con-formed to the Poly5 polynomial function,with variances above 0.99.Column bioleaching experiments were performed at a scale of 1 kg.The self-propelled low-pH environment increased the leaching efficiency,which resulted in a leaching rate of 98.88%for rare earths after 117 h.X-ray diffraction and scanning electron microscopy revealed that the samples mainly comprised quartz,kaolinite,orthoclase,mus-covite,and zeolite,which were predominantly present in the form of lumps,flakes,rods,and small particles.After bioleaching,the wave intensity of quartz,kaolinite,orthoclase,and muscovite increased,and that of zeolite decreased considerably.A diminution in the number of fine particles indicated the dissolution of small quantities of clay minerals.Ultimately,the differentiated bioleaching mechanism of various forms of rare earths was discussed based on experimental phenomena.展开更多
This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubbe...This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubber(TPR)used in the footwear industry with un-crosslinked polycaprolactone(PCL)to create two samples,namely TP6040 and TP7030.The shape memory behavior,elasticity,and thermo-mechanical response of these rubbers were systematically investigated.The experimental results demonstrated outstanding shape memory performance,with both samples achieving shape fixity ratios(Rf)and shape recovery ratios(R_(r))exceeding 94%.TP6040 exhibited a fitting time of 80 s at body temperature(37℃),indicating a rapid response for shape fixing.The materials also showed good elasticity before and after programming,which is crucial for comfort fitting.These findings suggest that the developed shape memory thermoplastic rubber has potential applications in personalized comfort fitting products,offering advantages over traditional customization techniques in terms of efficiency and cost-effectiveness.展开更多
Passive optical motion capture technology is an effective mean to conduct high-precision pose estimation of small scenes of mobile robots;nevertheless,in the case of complex background and stray light interference in ...Passive optical motion capture technology is an effective mean to conduct high-precision pose estimation of small scenes of mobile robots;nevertheless,in the case of complex background and stray light interference in the scene,due to the infuence of target adhesion and environmental reflection,this technology cannot estimate the pose accurately.A passive binocular optical motion capture technology under complex illumination based on binocular camera and fixed retroreflective marker balls has been proposed.By fixing multiple hemispherical retrorefective marker balls on a rigid base,it uses binocular camera for depth estimation to obtain the fixed position relationship between the feature points.After performing unsupervised state estimation without manual operation,it overcomes the infuence of refection spots in the background.Meanwhile,contour extraction and ellipse least square fitting are used to extract the marker balls with incomplete shape as the feature points,so as to solve the problem of target adhesion in the scene.A FANUC m10i-a robot moving with 6-DOF is used for verification using the above methods in a complex lighting environment of a welding laboratory.The result shows that the average of absolute position errors is 5.793mm,the average of absolute rotation errors is 1.997°the average of relative position errors is 0.972 mm,and the average of relative rotation errors is 0.002°.Therefore,this technology meets the requirements of high-precision measurement in a complex lighting environment when estimating the 6-DOF-motion mobile robot and has very significant application prospects in complex scenes.展开更多
The Dazu Rock Carvings in Chongqing were inscribed on the World Heritage List in 1999.In recent years,the Dazu Rock Carvings have faced environmental challenges such as geological forces,increased precipitation,pollut...The Dazu Rock Carvings in Chongqing were inscribed on the World Heritage List in 1999.In recent years,the Dazu Rock Carvings have faced environmental challenges such as geological forces,increased precipitation,pollution and tourism,which have led to rock deterioration and structural instability.The multi-source monitoring system for the protection of the rock carvings,based on the Internet of Things,includes Global Navigation Satellite System(GNSS)displacement monitoring,static level displacement monitoring,laser rangefinder displacement monitoring,roof pressure sensor monitoring and environmental damage monitoring.This paper analyses data from each sub-monitoring system within the multi-source monitoring system applied to Yuanjue Cave in the Dazu Rock Carvings.Initially,a correlation analysis between climate monitoring data and roof displacement data was carried out to assess the effect of temperature.Based on the results of the analysis,a temperature correction equation for the laser rangefinder was derived to improve the laser rangefinder displacement monitoring system.The improved system was then used to monitor Cave 168,revealing the deformation and erosion patterns of the roof.The research results demonstrate that the multiparameter monitoring system is capable of accurately measuring and analyzing the stability of the Dazu stone carvings,as well as the effects of environmental conditions on them.The use of the Internet of Things(IoT)and real-time data collection to monitor rock deformation and environmental conditions is an innovative application of technology in cultural heritage conservation.Interpretation of the monitoring system and statistical correlation analysis of temperature and laser rangefinder data highlight the thoroughness of the methodology in this paper and its relevance to sustainable mountain development.In the future,multi-source monitoring systems will have a broader application in the conservation of other UNESCO World Heritage Sites.展开更多
Land use sustainability is a pivotal concern in contemporary ecological protection efforts,necessitating a comprehensive understanding of the ramifications of changes in land use intensity(LUI)on ecosystem services(ES...Land use sustainability is a pivotal concern in contemporary ecological protection efforts,necessitating a comprehensive understanding of the ramifications of changes in land use intensity(LUI)on ecosystem services(ESs).Although ecological control zoning typically emphasizes ES outcomes,it tends to overlook the impacts of human activity intensity.This research focuses on the Yellow River Basin and integrates various data sources,encompassing land use,meteorological,soil,and socioeconomic data from 1980 to 2020.Using the InVEST model,quadratic polynomial fitting,and cluster analysis,this work evaluates the spatiotemporal changes and zoning characteristics of LUI and three ESs—water yield,soil conservation,and habitat quality—to explore the influence of LUI changes on ESs.The results indicate that from 1980 to 2020,LUI shows a sustained increase with considerable spatial heterogeneity,gradually intensifying from upstream to downstream areas.The interannual variability of ESs is minimal,with substantial local fluctuations but overall minor changes.LUI correlates positively with ESs.Based on regional ESs,the Yellow River Basin is categorized into four primary ecological function zones:ecological restoration,ecological pressure,ecological sustainability,and ecological conservation.Considering LUI characteristics,this categorization is further refined into six secondary function zones:ecological restoration,ecological transition,ecological overload,potential development,eco-economic carrying,and ecological conservation.This study provides a scientific foundation for land use planning and ecological conservation policy formulation within the watershed area.展开更多
In the context of climate change,countries in West Africa are faced with recurrent flooding with catastrophic consequences,that makes it imperative to have access to rainfall information on fine spatial and temporal s...In the context of climate change,countries in West Africa are faced with recurrent flooding with catastrophic consequences,that makes it imperative to have access to rainfall information on fine spatial and temporal scales for better monitoring and prediction of these phenomena,as could be provided by weather radars.Based on an extensive archive of data from the X-band polarimetric radar and rain gauges observations gathered during the intensive AMMA campaigns in 2006–2007 and the Megha-Tropiques satellite measurement validation programme in 2010 in West Africa,we(i)simulated jointly realistic data for polarimetric radar variables and rain intensity using copula,and(ii)assessed rain rate estimation methods based on neural network(NN)inversion techniques and non-linearly calibrated parametric algorithms.The assessment of rainfall rate retrieval by these estimators is carried out using the part of the observations database not employed for calibration steps.The multiparametric algorithms R(ZH,K_(DP))and R(Z_(DR),K_(DP))perform better than R(ZH,Z_(DR))and R(ZH,Z_(DR),K_(DP)),especially since they are calibrated using copulas with upper tail dependencies,with KGE ranging in 0.68–0.75 and 0.79–0.82,respectively versus ranges of 0.40–0.64 and 0.20–0.51,for the two latter estimators.The neural network-based estimators RNN(Z_(DR),K_(DP))and RNN(ZH,K_(DP)),show KGE score characteristics comparable to those obtained from the best parametric relations,specifically optimized for the synthetic copula-based dataset.However,the neural network-based estimators were shown to be more robust when applied to a specific rainfall event.More specifically,neural network-based estimators trained on synthetic data are sensitive to the copulas’ability to capture the dependence between the variables of interest over the entire distribution of joint values.This leads to a near-cancellation of sensitivity to variability in the raindrop size distribution,as shown the coefficients of correlation near 1,especially for RNN(Z_(DR),K_(DP)),and for less extent RNN(Z_(H),K_(DP)).展开更多
The change in interannual precipitation variability(P_(IAV)),especially the part driven by El Niño–Southern Oscillation over the Pacific,has sparked worldwide concern.However,it is plagued by substantial uncerta...The change in interannual precipitation variability(P_(IAV)),especially the part driven by El Niño–Southern Oscillation over the Pacific,has sparked worldwide concern.However,it is plagued by substantial uncertainty,such as model uncertainty,internal variability,and scenario uncertainty.Single-model initial-condition large ensembles(SMILEs)and a polynomial fitting method were suggested to separate these uncertainty sources.However,the applicability of a widely used polynomial fitting method in the uncertainty separation of P_(IAV)projection remains unknown.This study compares three sources of uncertainty estimated from five SMILEs and 28 models with one ensemble member in phase 6 of the Coupled Model Intercomparison Project(CMIP6).Results show that the internal uncertainty based on models with one ensemble member calculated using the polynomial fitting method is significantly underestimated compared to SMILEs.However,internal variability in CMIP6 as represented in the pre-industrial control run,aligns closely with SMILEs.At 1.5°C warming above the preindustrial level,internal variability dominates globally,masking the externally forced P_(IAV)signal.At 2.0°C warming,both internal and model uncertainties are significant over regions like Central Africa,the equatorial Indian Ocean,the Maritime Continent,and the Arctic,while internal variability still dominates elsewhere.In some regions,the forced signal becomes distinguishable from internal variability.This study reveals the limitations of the polynomial fitting method in separating P_(IAV)projection uncertainties and emphasizes the importance of SMILEs for accurately quantifying uncertainty sources.It also suggests that improving the intermodel agreement at warming levels of 1.5°C and 2.0°C will not substantially reduce uncertainty in most regions.展开更多
The advancement of imaging resolution has made the impact of multi-frequency composite jitter in satellite platforms on non-collinear time delay and integration(TDI)charge-coupled device(CCD)imaging systems increasing...The advancement of imaging resolution has made the impact of multi-frequency composite jitter in satellite platforms on non-collinear time delay and integration(TDI)charge-coupled device(CCD)imaging systems increasingly critical.Moreover,the accuracy of jitter detection is constrained by the limited inter-chip overlap region inherent to non-collinear TDI CCDs.To address these challenges,a multi-frequency jitter detection method is proposed,achieving sub-pixel level error extraction.Furthermore,a multi-frequency jitter fitting approach utilizing a scale-adjustable sliding window is introduced.For composite multi-frequency jitter,spectral analysis decomposes the relative jitter error curve,while the scale-adjustable sliding window enables frequency-division fitting and modeling.Validation experiments using Gaofen-8(GF-8)remote sensing satellite imagery detected jitter at 0.65,20,and 100 Hz in the cross-track direction and at 0.5,100,and 120 Hz in the along-track direction,demonstrating the method’s precision in detecting platform jitter at sub-pixel accuracy(<0.2 pixels)and its efficacy in fitting and modeling for non-collinear TDI CCD imaging systems subject to multi-frequency jitter.展开更多
Comprehensive studies on CO_(2)breakthrough times and flooding effects are crucial for optimizing CO_(2)flooding strategies.This study utilized numerical simulations to investigate the effects of hydraulic fractures,p...Comprehensive studies on CO_(2)breakthrough times and flooding effects are crucial for optimizing CO_(2)flooding strategies.This study utilized numerical simulations to investigate the effects of hydraulic fractures,permeability,and CO_(2)injection rates on CO_(2)breakthrough times and cumulative oil production.Nonlinear relationships among the respective variables were established,with Sobol method analysis delineating the dominant control factors.The key findings indicate that although hydraulic fracturing shortens CO_(2)breakthrough time,it concurrently enhances cumulative oil production.The orientation of hydraulic fractures emerged as a pivotal factor influencing flooding effectiveness.Furthermore,lower permeability corresponds to lower initial oil production,while higher permeability corresponds to higher initial daily oil production.When reservoir permeability is 1 mD,oil production declines at 1000 days,and at 2 mD,it declines at 700 days.At a surface CO_(2)injection rate of 10,000 m^(3)/d,the daily oil production of a single well is approximately 7.5 m^(3),and this value remains relatively stable over time.The hierarchical order of influence on CO_(2)breakthrough and rapid rise times,from highest to lowest,is permeability,well spacing,CO_(2)injection rate,porosity,and hydraulic fracture conductivity.Similarly,the order of influence on cumulative oil production,from highest to lowest,is well spacing,porosity,permeability,CO_(2)injection rate,and hydraulic fracture conductivity.This paper analyzed the impact of geological and engineering parameters on CO_(2)flooding and oil production and provided insights to optimize CO_(2)injection strategies for enhanced oil recovery.展开更多
The energy spectrum of energetic particles in space often shows a non-thermal spectral shape with two spectral transitions/breaks over a wide energy range, carrying crucial information about their acceleration, releas...The energy spectrum of energetic particles in space often shows a non-thermal spectral shape with two spectral transitions/breaks over a wide energy range, carrying crucial information about their acceleration, release and transportation process. To self-consistently characterize the spectral features of energetic particles, here we propose a novel extended pan-spectrum(EPS) formula to fit the particle energy-flux spectrum, which has the merit that can incorporate many commonly used spectrum functions with one spectral transition, including the pan-spectrum, double-power-law, Kappa, Ellison-Ramaty(ER) functions, etc. The formula can also determine the spectral shape with two spectral transitions, including the triple-power-law function, Kappa distribution(at low energy)plus power law(at high energy), power law(at low energy) plus ER function, etc. Considering the uncertainties in both J and E, we can fit this EPS formula well to the representative energy spectra of various particle phenomena in space, including solar energetic particles(electrons, protons, ~3He and heavier ions), anomalous cosmic rays, solar wind suprathermal particles(halo and superhalo electrons;pick-up ions and the suprathermal tail), etc. Therefore, the EPS fitting can help us self-consistently determine the spectral features of different particle phenomena, and improve our understanding of the physical nature of the origin, acceleration, and transportation of energetic particles in space.展开更多
The accumulation of^(222)Rn and^(220)Rn progeny in poorly ventilated environments poses the risk of natural radiation exposure to the public.A previous study indicated that satisfactory results in determining the^(222...The accumulation of^(222)Rn and^(220)Rn progeny in poorly ventilated environments poses the risk of natural radiation exposure to the public.A previous study indicated that satisfactory results in determining the^(222)Rn and^(220)Rn progeny concentrations by measuring the total alpha counts at five time intervals within 560 min should be expected only in the case of high progeny concentrations in air.To complete the measurement within a relatively short period and adapt it for simultaneous measurements at comparatively lower^(222)Rn and^(220)Rn progeny concentrations,a novel mathematical model was proposed based on the radioactive decay law.This model employs a nonlinear fitting method to distinguish nuclides with overlapping spectra by utilizing the alpha particle counts of non-overlapping spectra within consecutive measurement cycles to obtain the concentrations of^(222)Rn and^(220)Rn progeny in air.Several verification experiments were conducted using an alpha spectrometer.The experimental results demonstrate that the concentrations of^(222)Rn and^(220)Rn progeny calculated by the new method align more closely with the actual circumstances than those calculated by the total count method,and their relative uncertainties are all within±16%.Furthermore,the measurement time was reduced to 90 min,representing an acceleration of 84%.The improved capability of the new method in distinguishing alpha particles with similar energies emitted from ^(218)Po and^(212)Bi,both approximately 6 MeV,contributed to realizing more accurate results.The proposed method has the potential advantage of measuring relatively low concentrations of^(222)Rn and^(220)Rn progeny in air more quickly via air filtration.展开更多
Inverse bremsstrahlung absorption in laser-heated plasmas is studied using the Fokker–Planck equation in the low-field limit.Compared with the commonly used fitting formulas of Langdon and Matte et al.,our work emplo...Inverse bremsstrahlung absorption in laser-heated plasmas is studied using the Fokker–Planck equation in the low-field limit.Compared with the commonly used fitting formulas of Langdon and Matte et al.,our work employs fewer approximations and provides more accurate predictions for the super-Gaussian orderβand the heating rate.Simulation results show that the super-Gaussian order is generally lower than the fitting results of Matte et al.,which leads to an increase in absorption.However,we find two other factors that reduce absorption:the high-order term of the collision frequency and the effects caused by high laser intensity.Therefore,the final simulated absorption can either be higher or lower,depending on the conditions.These phenomena are theoretically analyzed using the Fokker–Planck equation.Fitting formulas are proposed for the super-Gaussian order and the heating rate,showing a discrepancy within∼10%of the simulation results.We also compare the simulation results with the experimental results from several recent papers.展开更多
In seismic data processing, random noise seriously affects the seismic data quality and subsequently the interpretation. This study aims to increase the signal-to-noise ratio by suppressing random noise and improve th...In seismic data processing, random noise seriously affects the seismic data quality and subsequently the interpretation. This study aims to increase the signal-to-noise ratio by suppressing random noise and improve the accuracy of seismic data interpretation without losing useful information. Hence, we propose a structure-oriented polynomial fitting filter. At the core of structure-oriented filtering is the characterization of the structural trend and the realization of nonstationary filtering. First, we analyze the relation of the frequency response between two-dimensional（2D） derivatives and the 2D Hilbert transform. Then, we derive the noniterative seismic local dip operator using the 2D Hilbert transform to obtain the structural trend. Second, we select polynomial fitting as the nonstationary filtering method and expand the application range of the nonstationary polynomial fitting. Finally, we apply variableamplitude polynomial fitting along the direction of the dip to improve the adaptive structureoriented filtering. Model and field seismic data show that the proposed method suppresses the seismic noise while protecting structural information.展开更多
To extract the cable forces due to dead load in cable-stayed bridges from the monitoring data,the effects of various factors are eliminated step by step by different statistical methods.The information of cable tensio...To extract the cable forces due to dead load in cable-stayed bridges from the monitoring data,the effects of various factors are eliminated step by step by different statistical methods.The information of cable tension sensors recorded by the health monitoring system of Nanjing No.3 Yangtze River Bridge is taken as an example. Temperature effects are eliminated by linear fitting analysis;a 5-level wavelet de-noising method is applied to eliminate the noise signal by the wavelet basis function of DB8.The rest cable force data is tested by the method of extreme-value type-Ⅲ distribution, and the fitted location parameter is selected as the cable force due to dead load.The results show that the cable force has a linear relationship with temperature. Sometimes, the temperature effect is significant.Noise effect accounts for a small percentage,and the vehicle loads effect has twice the temperature effect on the traffic volume in 2007. The calculation results of other stay cables verify the reliability and validity of the proposed method.展开更多
基金Supported by the National Basic Research Program of China(2012CB025904)Zhengzhou Shengda University of Economics,Business and Management(SD-YB2025085)。
文摘Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the main contributions is proving this property using linear algebra instead of profound knowledge.This makes it easy to read and understand this fundamental fact.The proof of linear independence of a set of Gauss functions relies on the constructing method for one-dimensional space and on the deducing method for higher dimensions.Additionally,under the condition of preserving the same moments between the original function and interpolating function,both the interpolating existence and uniqueness are proven for GRBF in one-dimensional space.The final work demonstrates the application of the GRBF method to locate lunar olivine.By combining preprocessed data using GRBF with the removing envelope curve method,a program is created to find the position of lunar olivine based on spectrum data,and the numerical experiment shows that it is an effective scheme.
基金supported by Anhui Province Key Research and Development Program(No.2022107020012)Shenzhen Science and Technology Innovation Project(No.JSGG20191129102008260).
文摘A fast and accurate homography matrix method for four-wheel positioning detection was presented in the paper.Fewer sensors were required with simpler operation and faster detection.Firstly,eight feature points were extracted by using the target detection algorithm based on the fitting method.Secondly,six feature points were obtained by line fitting-based selection.Thirdly,from the selected six feature points,five points were randomly chosen to minimize the re-projection error.Finally,four points were randomly selected from these five feature points to find the homography matrix,and the other point was back to the homography matrix for verification.The experimental results show that the mean re-projection error is reduced by about 3.41%−4.57%compared with the modified RANSAC(Random sample consensus)algorithm.With the optimized algorithm,the error is reduced by about 12.81%−13.86%compared with the improved RANSAC algorithm.Compared with traditional targets,the average calibration time is reduced by about 26.95%−27.88%.The results indicated that the combination of target algorithm and optimization algorithm could ensure the accuracy and reliability of four-wheel positioning.
基金supported by the National Natural Science Foundation of China(12132015,12332015)。
文摘The ratio of the pressure drop force to the drag force,C_(P),is concerned for a non-closely fitting spherical particle settling along the central line in long rectangular tubes with different A_(r)(A_(r)is W/H,where W,H is length of the longer and shorter side of the rectangle respectively).Under Stokes flow conditions,C_(P0)for an infinitely small sphere in long rectangular tubes and C_(P)for a sphere in a long channel between two parallel layered barriers are both calculated.Then C_(P)of a sphere settling in long rectangular tubes are conducted with the direct-forcing fictitious domain(DF/FD)method.At large Reynolds number,the sphere settles unstably with a fluctuating velocity and C_(P).The fluctuation of Cp is much stronger than that of velocity and both fluctuations are stronger for less confined sphere.The influences of the particle Reynolds number(Re_(p))on C_(P)is similar to the existing experimental results in long circular tubes.At low Re_(p),C_(P)is a determined value and is calculated.For a given d/H(d sphere diameter),Cp gets its maximum value at one A_(r)in the range of[1,1.5].For a given A_(r),C_(P)is a quadratic function of d/H similar to that in a circular tube,and parameters of the quadratic function are got by curve fitting from numerical data.The constant term coefficients got have almost no difference with C_(P0)and are furtherly replaced by the latter to get new quadratic coefficients C_(P1).Lastly,an algebraic correlation of C_(P1)to A_(r)is developed.The predictions of Cp are good with a maximum relative error about 1.5%for a sphere with d/H not greater than0.7,compared to numerical results.
基金supported in part by the National Natural Science Foundation of China under Grant 42174164 and Grant 41704132in part by the Key Program of the Joint Fund of the Science,Technology,and Education of Sichuan Province,China under Grant 2024NSFSC1955+4 种基金in part by the Natural Science Foundation of Sichuan Province,China under Grant 2024NSFSC0080in part by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project under Grant SKLGP2022Z011in part by the Chengdu University of Technology Postgraduate Innovative Cultivation Program:Spatiotemporal Characterization of Seismic Signals for Tight Channel Sandstone Gas Reservoirs in the Synchro-Squeezing/Extracting Transform Domain under Grant CDUT2023BJCx002in part by the Creative Research Groups of the Natural Science Foundation of Sichuan under Grant 2023NSFSC198414th Five Year Plan Major Science and Technology Project of CNOOC under Grant KJGG2022-0903.
文摘As seismic signals propagate underground,the subsurface media absorb high-frequency components,decreasing seismic resolution and limiting the identification and characterization of thin reservoirs.To address the limitation,this paper proposes a multichannel spectral fitting(MSF)method.The MSF method aims to enhance seismic resolution by considering the spectral characteristics and the correlations between adjacent seismic traces.The key to the MSF method involves utilizing the amplitude spectrum of the attenuated Ricker wavelet to construct an objective function for spectral fitting,leading to improved seismic resolution.Furthermore,the MSF method establishes the correlation between adjacent seismic traces as a constraint to stably solve the target parameters based on the entire seismic spectrum,which helps obtain horizontally consistent and more realistic seismic signals.Synthetic and field seismic examples demonstrate that the proposed method not only provides higher-resolution seismic signals but also reveals more fine details of thin reservoirs compared to the time-variant spectral whitening method.It is concluded that the MSF method is a promising tool for seismic signal processing.
基金supported by the Key Laboratory of Ionic Rare Earth Resources and Environment,Ministry of Natural Resources of the People’s Republic of China(No.2022IRERE201)the Natural Science Foundation of Jiangsu Province,China(No.BK20231074)+4 种基金the National Natural Science Foundation of China(Nos.52404371,52274351,and 52304365)the National Key Research and Development Project of China(No.2021YFC2902202)the Natural Science Foundation of Guangdong Province,China(No.2023A1515011847)the Natural Science Foundation of Jiangxi Province,China(Nos.20232ACB204014 and 20232ACB204016)the Open Fund for Technology Innovation Center for Comprehensive Utilization of Strategic Mineral Resources of Ministry of Natural Resources(No.CCUM-KY-2305).
文摘Indigenous microbial communities were employed after subculture in stirred and column bioleaching experiments involving ion-adsorption type rare earth ore.The microbial eukaryotic communities exhibited dramatically varying diversity and structure across culture compositions.Compared with Czapek and sucrose medium,the community cultured in a nutrient broth(NB)medium had a high-er diversity,and it was mainly composed of Zygosaccharomyces,Ustilago,Kodamaea,Malassezia,and Aspergillus.These microorgan-isms secrete organic acids,such as citric acid,malic acid,gluconic acid,and itaconic acid,which provide effective coordination electrons through hydroxyl and carboxyl groups.Stirred bioleaching experiments were conducted to investigate the effect of community,inoculum dosage,liquid–solid ratio,and time on the leaching efficiency.Stirred bioleaching resulted in a concentration limitation phenomenon.When the inoculum dosage of the community cultured in NB medium was 70vol%,the liquid–solid ratio was 5.0 mL·g^(-1),and the time was 60 min,the upward trend of rare earths leaching rate has become very small.Specifically,the leaching rates of detectable La,Ce,and Y were approximately 92.49%,92.42%,and 94.39%,respectively.The leaching efficiency and the three influencing factors all con-formed to the Poly5 polynomial function,with variances above 0.99.Column bioleaching experiments were performed at a scale of 1 kg.The self-propelled low-pH environment increased the leaching efficiency,which resulted in a leaching rate of 98.88%for rare earths after 117 h.X-ray diffraction and scanning electron microscopy revealed that the samples mainly comprised quartz,kaolinite,orthoclase,mus-covite,and zeolite,which were predominantly present in the form of lumps,flakes,rods,and small particles.After bioleaching,the wave intensity of quartz,kaolinite,orthoclase,and muscovite increased,and that of zeolite decreased considerably.A diminution in the number of fine particles indicated the dissolution of small quantities of clay minerals.Ultimately,the differentiated bioleaching mechanism of various forms of rare earths was discussed based on experimental phenomena.
基金supported by the Aeronautical Science Foundation of China(Grant Nos.2024Z009052003,20230038052001 and 20230015052002)the Third Batch of Science and Technology Plan Projects in Changzhou City in 2023(Applied Basic Research,Grant No.CJ20230080).
文摘This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubber(TPR)used in the footwear industry with un-crosslinked polycaprolactone(PCL)to create two samples,namely TP6040 and TP7030.The shape memory behavior,elasticity,and thermo-mechanical response of these rubbers were systematically investigated.The experimental results demonstrated outstanding shape memory performance,with both samples achieving shape fixity ratios(Rf)and shape recovery ratios(R_(r))exceeding 94%.TP6040 exhibited a fitting time of 80 s at body temperature(37℃),indicating a rapid response for shape fixing.The materials also showed good elasticity before and after programming,which is crucial for comfort fitting.These findings suggest that the developed shape memory thermoplastic rubber has potential applications in personalized comfort fitting products,offering advantages over traditional customization techniques in terms of efficiency and cost-effectiveness.
基金the National Key Research and Development Program of China(No.2018YFB1305005)。
文摘Passive optical motion capture technology is an effective mean to conduct high-precision pose estimation of small scenes of mobile robots;nevertheless,in the case of complex background and stray light interference in the scene,due to the infuence of target adhesion and environmental reflection,this technology cannot estimate the pose accurately.A passive binocular optical motion capture technology under complex illumination based on binocular camera and fixed retroreflective marker balls has been proposed.By fixing multiple hemispherical retrorefective marker balls on a rigid base,it uses binocular camera for depth estimation to obtain the fixed position relationship between the feature points.After performing unsupervised state estimation without manual operation,it overcomes the infuence of refection spots in the background.Meanwhile,contour extraction and ellipse least square fitting are used to extract the marker balls with incomplete shape as the feature points,so as to solve the problem of target adhesion in the scene.A FANUC m10i-a robot moving with 6-DOF is used for verification using the above methods in a complex lighting environment of a welding laboratory.The result shows that the average of absolute position errors is 5.793mm,the average of absolute rotation errors is 1.997°the average of relative position errors is 0.972 mm,and the average of relative rotation errors is 0.002°.Therefore,this technology meets the requirements of high-precision measurement in a complex lighting environment when estimating the 6-DOF-motion mobile robot and has very significant application prospects in complex scenes.
基金financial support from the National Natural Science Foundation of China(No.42377154)。
文摘The Dazu Rock Carvings in Chongqing were inscribed on the World Heritage List in 1999.In recent years,the Dazu Rock Carvings have faced environmental challenges such as geological forces,increased precipitation,pollution and tourism,which have led to rock deterioration and structural instability.The multi-source monitoring system for the protection of the rock carvings,based on the Internet of Things,includes Global Navigation Satellite System(GNSS)displacement monitoring,static level displacement monitoring,laser rangefinder displacement monitoring,roof pressure sensor monitoring and environmental damage monitoring.This paper analyses data from each sub-monitoring system within the multi-source monitoring system applied to Yuanjue Cave in the Dazu Rock Carvings.Initially,a correlation analysis between climate monitoring data and roof displacement data was carried out to assess the effect of temperature.Based on the results of the analysis,a temperature correction equation for the laser rangefinder was derived to improve the laser rangefinder displacement monitoring system.The improved system was then used to monitor Cave 168,revealing the deformation and erosion patterns of the roof.The research results demonstrate that the multiparameter monitoring system is capable of accurately measuring and analyzing the stability of the Dazu stone carvings,as well as the effects of environmental conditions on them.The use of the Internet of Things(IoT)and real-time data collection to monitor rock deformation and environmental conditions is an innovative application of technology in cultural heritage conservation.Interpretation of the monitoring system and statistical correlation analysis of temperature and laser rangefinder data highlight the thoroughness of the methodology in this paper and its relevance to sustainable mountain development.In the future,multi-source monitoring systems will have a broader application in the conservation of other UNESCO World Heritage Sites.
基金National Natural Science Foundation of China,No.42101258Natural Science Foundation of Shandong Province,No.ZR2024MD073+1 种基金The Humanities and Social Sciences Youth FoundationMinistry of Education,No.19YJCZH144。
文摘Land use sustainability is a pivotal concern in contemporary ecological protection efforts,necessitating a comprehensive understanding of the ramifications of changes in land use intensity(LUI)on ecosystem services(ESs).Although ecological control zoning typically emphasizes ES outcomes,it tends to overlook the impacts of human activity intensity.This research focuses on the Yellow River Basin and integrates various data sources,encompassing land use,meteorological,soil,and socioeconomic data from 1980 to 2020.Using the InVEST model,quadratic polynomial fitting,and cluster analysis,this work evaluates the spatiotemporal changes and zoning characteristics of LUI and three ESs—water yield,soil conservation,and habitat quality—to explore the influence of LUI changes on ESs.The results indicate that from 1980 to 2020,LUI shows a sustained increase with considerable spatial heterogeneity,gradually intensifying from upstream to downstream areas.The interannual variability of ESs is minimal,with substantial local fluctuations but overall minor changes.LUI correlates positively with ESs.Based on regional ESs,the Yellow River Basin is categorized into four primary ecological function zones:ecological restoration,ecological pressure,ecological sustainability,and ecological conservation.Considering LUI characteristics,this categorization is further refined into six secondary function zones:ecological restoration,ecological transition,ecological overload,potential development,eco-economic carrying,and ecological conservation.This study provides a scientific foundation for land use planning and ecological conservation policy formulation within the watershed area.
文摘In the context of climate change,countries in West Africa are faced with recurrent flooding with catastrophic consequences,that makes it imperative to have access to rainfall information on fine spatial and temporal scales for better monitoring and prediction of these phenomena,as could be provided by weather radars.Based on an extensive archive of data from the X-band polarimetric radar and rain gauges observations gathered during the intensive AMMA campaigns in 2006–2007 and the Megha-Tropiques satellite measurement validation programme in 2010 in West Africa,we(i)simulated jointly realistic data for polarimetric radar variables and rain intensity using copula,and(ii)assessed rain rate estimation methods based on neural network(NN)inversion techniques and non-linearly calibrated parametric algorithms.The assessment of rainfall rate retrieval by these estimators is carried out using the part of the observations database not employed for calibration steps.The multiparametric algorithms R(ZH,K_(DP))and R(Z_(DR),K_(DP))perform better than R(ZH,Z_(DR))and R(ZH,Z_(DR),K_(DP)),especially since they are calibrated using copulas with upper tail dependencies,with KGE ranging in 0.68–0.75 and 0.79–0.82,respectively versus ranges of 0.40–0.64 and 0.20–0.51,for the two latter estimators.The neural network-based estimators RNN(Z_(DR),K_(DP))and RNN(ZH,K_(DP)),show KGE score characteristics comparable to those obtained from the best parametric relations,specifically optimized for the synthetic copula-based dataset.However,the neural network-based estimators were shown to be more robust when applied to a specific rainfall event.More specifically,neural network-based estimators trained on synthetic data are sensitive to the copulas’ability to capture the dependence between the variables of interest over the entire distribution of joint values.This leads to a near-cancellation of sensitivity to variability in the raindrop size distribution,as shown the coefficients of correlation near 1,especially for RNN(Z_(DR),K_(DP)),and for less extent RNN(Z_(H),K_(DP)).
基金funded by the National Natural Science Foundation of China(Grant No.42425504).
文摘The change in interannual precipitation variability(P_(IAV)),especially the part driven by El Niño–Southern Oscillation over the Pacific,has sparked worldwide concern.However,it is plagued by substantial uncertainty,such as model uncertainty,internal variability,and scenario uncertainty.Single-model initial-condition large ensembles(SMILEs)and a polynomial fitting method were suggested to separate these uncertainty sources.However,the applicability of a widely used polynomial fitting method in the uncertainty separation of P_(IAV)projection remains unknown.This study compares three sources of uncertainty estimated from five SMILEs and 28 models with one ensemble member in phase 6 of the Coupled Model Intercomparison Project(CMIP6).Results show that the internal uncertainty based on models with one ensemble member calculated using the polynomial fitting method is significantly underestimated compared to SMILEs.However,internal variability in CMIP6 as represented in the pre-industrial control run,aligns closely with SMILEs.At 1.5°C warming above the preindustrial level,internal variability dominates globally,masking the externally forced P_(IAV)signal.At 2.0°C warming,both internal and model uncertainties are significant over regions like Central Africa,the equatorial Indian Ocean,the Maritime Continent,and the Arctic,while internal variability still dominates elsewhere.In some regions,the forced signal becomes distinguishable from internal variability.This study reveals the limitations of the polynomial fitting method in separating P_(IAV)projection uncertainties and emphasizes the importance of SMILEs for accurately quantifying uncertainty sources.It also suggests that improving the intermodel agreement at warming levels of 1.5°C and 2.0°C will not substantially reduce uncertainty in most regions.
文摘The advancement of imaging resolution has made the impact of multi-frequency composite jitter in satellite platforms on non-collinear time delay and integration(TDI)charge-coupled device(CCD)imaging systems increasingly critical.Moreover,the accuracy of jitter detection is constrained by the limited inter-chip overlap region inherent to non-collinear TDI CCDs.To address these challenges,a multi-frequency jitter detection method is proposed,achieving sub-pixel level error extraction.Furthermore,a multi-frequency jitter fitting approach utilizing a scale-adjustable sliding window is introduced.For composite multi-frequency jitter,spectral analysis decomposes the relative jitter error curve,while the scale-adjustable sliding window enables frequency-division fitting and modeling.Validation experiments using Gaofen-8(GF-8)remote sensing satellite imagery detected jitter at 0.65,20,and 100 Hz in the cross-track direction and at 0.5,100,and 120 Hz in the along-track direction,demonstrating the method’s precision in detecting platform jitter at sub-pixel accuracy(<0.2 pixels)and its efficacy in fitting and modeling for non-collinear TDI CCD imaging systems subject to multi-frequency jitter.
基金supported by the China Postdoctoral Science Foundation(No.2024M752803)the National Natural Science Foundation of China(No.52179112)+1 种基金the Open Fund of National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,China(No.PLN2023-02)the Open Fund of Key Laboratory of Deep Geothermal Resources,Ministry of Natural Resources of the People's Republic of China(No.KLDGR2024B01).
文摘Comprehensive studies on CO_(2)breakthrough times and flooding effects are crucial for optimizing CO_(2)flooding strategies.This study utilized numerical simulations to investigate the effects of hydraulic fractures,permeability,and CO_(2)injection rates on CO_(2)breakthrough times and cumulative oil production.Nonlinear relationships among the respective variables were established,with Sobol method analysis delineating the dominant control factors.The key findings indicate that although hydraulic fracturing shortens CO_(2)breakthrough time,it concurrently enhances cumulative oil production.The orientation of hydraulic fractures emerged as a pivotal factor influencing flooding effectiveness.Furthermore,lower permeability corresponds to lower initial oil production,while higher permeability corresponds to higher initial daily oil production.When reservoir permeability is 1 mD,oil production declines at 1000 days,and at 2 mD,it declines at 700 days.At a surface CO_(2)injection rate of 10,000 m^(3)/d,the daily oil production of a single well is approximately 7.5 m^(3),and this value remains relatively stable over time.The hierarchical order of influence on CO_(2)breakthrough and rapid rise times,from highest to lowest,is permeability,well spacing,CO_(2)injection rate,porosity,and hydraulic fracture conductivity.Similarly,the order of influence on cumulative oil production,from highest to lowest,is well spacing,porosity,permeability,CO_(2)injection rate,and hydraulic fracture conductivity.This paper analyzed the impact of geological and engineering parameters on CO_(2)flooding and oil production and provided insights to optimize CO_(2)injection strategies for enhanced oil recovery.
基金supported in part by NSFC under contracts 42225404, 42127803, 42150105by National Key R&D Program of China No. 2021YFA0718600by ISSI-BJ through the international teams Nos. 23-581 and 56。
文摘The energy spectrum of energetic particles in space often shows a non-thermal spectral shape with two spectral transitions/breaks over a wide energy range, carrying crucial information about their acceleration, release and transportation process. To self-consistently characterize the spectral features of energetic particles, here we propose a novel extended pan-spectrum(EPS) formula to fit the particle energy-flux spectrum, which has the merit that can incorporate many commonly used spectrum functions with one spectral transition, including the pan-spectrum, double-power-law, Kappa, Ellison-Ramaty(ER) functions, etc. The formula can also determine the spectral shape with two spectral transitions, including the triple-power-law function, Kappa distribution(at low energy)plus power law(at high energy), power law(at low energy) plus ER function, etc. Considering the uncertainties in both J and E, we can fit this EPS formula well to the representative energy spectra of various particle phenomena in space, including solar energetic particles(electrons, protons, ~3He and heavier ions), anomalous cosmic rays, solar wind suprathermal particles(halo and superhalo electrons;pick-up ions and the suprathermal tail), etc. Therefore, the EPS fitting can help us self-consistently determine the spectral features of different particle phenomena, and improve our understanding of the physical nature of the origin, acceleration, and transportation of energetic particles in space.
基金supported by the National Natural Science Foundation of China(No.12075112)Natural Science Foundation of Hunan(No.2023JJ50121),Natural Science Foundation of Hunan Province(No.2023JJ50091)Key Projects of Hunan Provincial Department of Education(No.23A0516).
文摘The accumulation of^(222)Rn and^(220)Rn progeny in poorly ventilated environments poses the risk of natural radiation exposure to the public.A previous study indicated that satisfactory results in determining the^(222)Rn and^(220)Rn progeny concentrations by measuring the total alpha counts at five time intervals within 560 min should be expected only in the case of high progeny concentrations in air.To complete the measurement within a relatively short period and adapt it for simultaneous measurements at comparatively lower^(222)Rn and^(220)Rn progeny concentrations,a novel mathematical model was proposed based on the radioactive decay law.This model employs a nonlinear fitting method to distinguish nuclides with overlapping spectra by utilizing the alpha particle counts of non-overlapping spectra within consecutive measurement cycles to obtain the concentrations of^(222)Rn and^(220)Rn progeny in air.Several verification experiments were conducted using an alpha spectrometer.The experimental results demonstrate that the concentrations of^(222)Rn and^(220)Rn progeny calculated by the new method align more closely with the actual circumstances than those calculated by the total count method,and their relative uncertainties are all within±16%.Furthermore,the measurement time was reduced to 90 min,representing an acceleration of 84%.The improved capability of the new method in distinguishing alpha particles with similar energies emitted from ^(218)Po and^(212)Bi,both approximately 6 MeV,contributed to realizing more accurate results.The proposed method has the potential advantage of measuring relatively low concentrations of^(222)Rn and^(220)Rn progeny in air more quickly via air filtration.
基金supported by the Natural Science Foundation of China(Grant Nos.12035002,12405235,and U2430207)the China Postdoctoral Science Foundation(Grant No.2023M740336)the CAEP foundation(Grant No.YZJJZQ2023020).
文摘Inverse bremsstrahlung absorption in laser-heated plasmas is studied using the Fokker–Planck equation in the low-field limit.Compared with the commonly used fitting formulas of Langdon and Matte et al.,our work employs fewer approximations and provides more accurate predictions for the super-Gaussian orderβand the heating rate.Simulation results show that the super-Gaussian order is generally lower than the fitting results of Matte et al.,which leads to an increase in absorption.However,we find two other factors that reduce absorption:the high-order term of the collision frequency and the effects caused by high laser intensity.Therefore,the final simulated absorption can either be higher or lower,depending on the conditions.These phenomena are theoretically analyzed using the Fokker–Planck equation.Fitting formulas are proposed for the super-Gaussian order and the heating rate,showing a discrepancy within∼10%of the simulation results.We also compare the simulation results with the experimental results from several recent papers.
基金Research supported by the 863 Program of China(No.2012AA09A20103)the National Natural Science Foundation of China(No.41274119,No.41174080,and No.41004041)
文摘In seismic data processing, random noise seriously affects the seismic data quality and subsequently the interpretation. This study aims to increase the signal-to-noise ratio by suppressing random noise and improve the accuracy of seismic data interpretation without losing useful information. Hence, we propose a structure-oriented polynomial fitting filter. At the core of structure-oriented filtering is the characterization of the structural trend and the realization of nonstationary filtering. First, we analyze the relation of the frequency response between two-dimensional（2D） derivatives and the 2D Hilbert transform. Then, we derive the noniterative seismic local dip operator using the 2D Hilbert transform to obtain the structural trend. Second, we select polynomial fitting as the nonstationary filtering method and expand the application range of the nonstationary polynomial fitting. Finally, we apply variableamplitude polynomial fitting along the direction of the dip to improve the adaptive structureoriented filtering. Model and field seismic data show that the proposed method suppresses the seismic noise while protecting structural information.
基金The National Natural Science Foundation of China(No.51208096)the Major Scientific and Technological Special Project of Jiangsu Provincial Communications Department(No.2014Y02)
文摘To extract the cable forces due to dead load in cable-stayed bridges from the monitoring data,the effects of various factors are eliminated step by step by different statistical methods.The information of cable tension sensors recorded by the health monitoring system of Nanjing No.3 Yangtze River Bridge is taken as an example. Temperature effects are eliminated by linear fitting analysis;a 5-level wavelet de-noising method is applied to eliminate the noise signal by the wavelet basis function of DB8.The rest cable force data is tested by the method of extreme-value type-Ⅲ distribution, and the fitted location parameter is selected as the cable force due to dead load.The results show that the cable force has a linear relationship with temperature. Sometimes, the temperature effect is significant.Noise effect accounts for a small percentage,and the vehicle loads effect has twice the temperature effect on the traffic volume in 2007. The calculation results of other stay cables verify the reliability and validity of the proposed method.
