Pitch deviation at rack joints(PDRJ) is a common error in rack railways. It directly affects the contact characteristics between the rack and gear and leads to accelerated surface wear. This threatens the stability an...Pitch deviation at rack joints(PDRJ) is a common error in rack railways. It directly affects the contact characteristics between the rack and gear and leads to accelerated surface wear. This threatens the stability and service life of the rack system, and the theoretical understanding of this issue remains limited. To address this gap, this study develops an improved tooth wear model that simultaneously accounts for the instantaneous variations in meshing stiffness and dynamic transmission error(DTE) induced by PDRJ, as well as the real-time correlation between gear-rack contact position and meshing excitation. Subsequently, the rack tooth load and wear characteristics are evaluated through the rack vehicle-track coupled dynamics and gear-rack contact model. The model's reliability is verified through field measurements. Moreover, the influence of varying PDRJ levels on load sharing factors, surface wear depth, and rack displacement is investigated. The results show that PDRJ disrupts the theoretical gear-rack meshing process, resulting in non-uniform load distribution and accelerated wear, particularly in the addendum and dedendum regions of the rack teeth. This study provides valuable insights into the rack surface wear mechanism under PDRJ.展开更多
The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on ...The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on the mechanical performance of anchor rods,with limited attention to the coupled evolution of strain and temperature fields during tensile deformation.This knowledge gap hinders a comprehensive understanding of the synergistic mechanical-thermal response mechanisms in anchor rods under loading conditions.To address this limitation,the present study systematically investigated the evolution of strain and temperature fields,along with their correlation,during the test of micro-negative Poisson's ratio(NPR)and ordinary Poisson's ratio(PR)anchor rods.Digital image correlation(DIC)and infrared thermography(IRT)techniques were employed for this exploration.The uniaxial tensile tests were conducted at two different rates,and the ordinary PR anchor rod(Q235 anchor rod)was established as a control group for comparative analysis.The findings reveal that the micro-NPR anchor rod exhibit strain localization at multiple locations during the tensile process,whereas Q235 anchors show local strain concentration in only one region.The standard deviation evolution curves for both the strain and temperature field exhibit two distinct phases in the two anchor rods.The evolution patterns between these two types of curves are basically consistent.The two standard deviation curves for the micro-NPR anchor rod display a wavy increase in the second phase,while for the Q235 anchor rod,they increase steadily until the specimen is damaged.The correlation analysis reveals that the standard deviations of strain and temperature differences for both types of anchor rods are significantly correlated.These findings demonstrate the synergistic evolution mechanism of deformation and thermal response,providing a potential foundation for utilizing thermal monitoring to assess the stability of rock support structures.展开更多
Although machine learning models have achieved high enough accuracy in predicting shield position deviations,their“black box”nature makes the prediction mechanisms and decision-making processes opaque,leading to wea...Although machine learning models have achieved high enough accuracy in predicting shield position deviations,their“black box”nature makes the prediction mechanisms and decision-making processes opaque,leading to weaker explanations and practicability.This study introduces a novel explainable deep learning framework comprising the Informer model with enhanced attention mechanisms(EAMInfor)and deep learning important features(DeepLIFT),aimed at improving the prediction accuracy of shield position deviations and providing interpretability for predictive results.The EAMInfor model attempts to integrate channel attention,spatial attention,and simple attention modules to improve the Informer model's performance.The framework is tested with the four different geological conditions datasets generated from the Xiamen metro line 3,China.Results show that the EAMInfor model outperforms the traditional Informer and comparison models.The analysis with the DeepLIFT method indicates that the push thrust of push cylinder and the earth chamber pressure are the most significant features,while the stroke length of the push cylinder demonstrated lower importance.Furthermore,the variation trends in the significance of data points within input sequences exhibit substantial differences between single and composite strata.This framework not only improves predictive accuracy but also strengthens the credibility and reliability of the results.展开更多
In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):104...In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192].展开更多
Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimila...Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimilation is quite challenging.This is because there is limited knowledge about the cross-component background error covariance(BEC)between LST and atmospheric state variables.This study aims to clarify whether there is a relationship between the error of LST and atmospheric variables,and whether this relationship varies spatially and temporally.To this end,the BEC coupled with atmospheric variables and LST was constructed(LST-BEC),and its characteristics were analyzed based on the 2023 mei-yu season.The general characteristics of LST-BEC show that the LST is mainly correlated with the atmospheric temperature and the correlation decreases gradually with a rise in atmospheric height,and the error standard deviation of the LST is noticeably larger than that of the low-level atmospheric temperature.The spatiotemporal characteristics of LST-BEC on the heavy-rain day and light-rain day show that the error correlation and error standard deviation of LST and low-level atmospheric temperature and humidity are closely related to the weather background,and also have obvious diurnal variations.These results provide valuable information for strongly coupled land-atmosphere assimilation.展开更多
To address the issue of coordinated control of multiple hydrogen and battery storage units to suppress the grid-injected power deviation of wind farms,an online optimization strategy for Battery-hydrogen hybrid energy...To address the issue of coordinated control of multiple hydrogen and battery storage units to suppress the grid-injected power deviation of wind farms,an online optimization strategy for Battery-hydrogen hybrid energy storage systems based on measurement feedback is proposed.First,considering the high charge/discharge losses of hydrogen storage and the low energy density of battery storage,an operational optimization objective is established to enable adaptive energy adjustment in the Battery-hydrogen hybrid energy storage system.Next,an online optimization model minimizing the operational cost of the hybrid system is constructed to suppress grid-injected power deviations with satisfying the operational constraints of hydrogen storage and batteries.Finally,utilizing the online measurement of the energy states of hydrogen storage and batteries,an online optimization strategy based on measurement feedback is designed.Case study results show:before and after smoothing the fluctuations in wind power,the time when the power exceeded the upper and lower limits of the grid-injected power accounted for 24.1%and 1.45%of the total time,respectively,the proposed strategy can effectively keep the grid-injected power deviations of wind farms within the allowable range.Hydrogen storage and batteries respectively undertake long-term and short-term charge/discharge tasks,effectively reducing charge/discharge losses of the Battery-hydrogen hybrid energy storage systems and improving its operational efficiency.展开更多
Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address th...Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address this issue,we propose a geometric error cost sensitivity-based accuracy allocation method for five-axis machine tools.A geometric error model consisting of 4l error components is constructed based on homogeneous transformation matrices.Volumetric points with positional and tool direction deviations are randomly sampled to evaluate the accuracy of the machine tool.The sensitivity of each error component at these sampling points is analyzed using the Sobol method.To balance the needs of geometric precision and manufacturing cost,a geometric error cost sensitivity function is developed to estimate the required cost.By allocating error components affecting tool direction deviation first and the remaining components second,this allocation scheme ensures that both deviations meet the requirements.We also perform numerical simulation of a BC-type(B-axis and C-axis type)five-axis machine tool to validate the method.The results show that the new allocation scheme reduces the total geometric error cost by 27.8%compared to a uniform allocation scheme,and yields the same positional and tool direction machining accuracies.展开更多
The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,c...The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,causing carbon storage exchanges.However,the relationship between carbon storage and land use change in the MRYR is not concerned,which results in the uncertainty in the simulation of carbon storage in this area.Land use changes directly affect the carbon storage capacity of ecosystems,and as an indicator reflecting the overall state of land use,land use degree has an important relationship with carbon storage.In this study,land use data and the integrated valuation of ecosystem services and trade-offs(InVEST)model were used to assess the trends in land use degree and carbon storage in the MRYR during 1980-2020.The potential impact index and the standard deviation ellipse(SDE)algorithm were applied to quantify and analyze the characteristics of the impact of land use changes on carbon storage.Subsequently,land use transitions that led to carbon storage variations and their spatial variations were determined.The results showed that:(1)the most significant periods of carbon storage changes and land use transitions were observed during 1990-1995 and 1995-2020,with the most changed areas locating in the east of Fenhe River and in northwestern Henan Province;(2)the positive impact of land use degree on carbon storage may be related to the environmental protection measures implemented along the Yellow River,while the negative impact may be associated with the expansion of construction land in plain areas;and(3)the conversion of other land use types to grassland was the primary factor affecting carbon storage changes during 1980-2020.In future land use planning,attention should be given to the direction of grassland conversion,and focus on reasonably limiting the development of construction land.To enhance carbon storage,it will be crucial to increase the area of high-carbon-density land types,such as forest land and grassland under the condition that the area of permanent farmland does not decrease.展开更多
In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are dif...In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are different from those of weak record numbers,which are interesting complements of the conclusions by Li and Yao[1].展开更多
In this paper we study the Freidlin-Wentzell's large deviation principle for the following nonlinear fractional stochastic heat equation driven by Gaussian noise∂/∂tu^(ε)=D_(δ)^(α)(t,x)+√εσ(u^(ε)(t,x))W(t,x...In this paper we study the Freidlin-Wentzell's large deviation principle for the following nonlinear fractional stochastic heat equation driven by Gaussian noise∂/∂tu^(ε)=D_(δ)^(α)(t,x)+√εσ(u^(ε)(t,x))W(t,x),(t,x)∈[0,T]×R,where D_(δ)^(α)is a nonlocal fractional differential operator and W is the Gaussian noise which is white in time and behaves as a fractional Brownian motion with Hurst index H satisfying 3-α/4<H<1/2,in the space variable.The weak convergence approach plays an important role.展开更多
In this paper,based on the structure-behavior coupling paradigm,we propose the concept of deviation of central town to describe the geography-market distance between farmers and the central regional town.Using the sur...In this paper,based on the structure-behavior coupling paradigm,we propose the concept of deviation of central town to describe the geography-market distance between farmers and the central regional town.Using the survey data from farmers in a poverty-stricken village in Western China,the impact of deviation of central town on farmers'livelihood strategies is analyzed.The results indicate that farmers exhibit spatial heterogeneity in their livelihood strategies.Those with low deviation show a strong inclination towards working in urban areas,while those with high deviation tend to integrate into rural industries.The deviation of central town influences farmers'livelihood strategies through the information effect,which is also affected by the level of rural infrastructure and public services,labor force structure and assistance policies.The obtained results are expected to provide guidance for promoting the integration of farmers into the urban-rural economic cycle based on sustainable livelihoods and connecting poverty alleviation with rural revitalization.展开更多
Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispat...Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispatching.Data-driven diagnostic methods often fail to account for the imbalanced distribution of data samples,leading to reduced classification performance in diagnosing load deviations in USC units.To address the class imbalance issue in USC load deviation datasets,this study proposes a diagnostic method based on the multi-label natural neighbor boundary oversampling technique(MLNaNBDOS).The method is articulated in three phases.Initially,the traditional binary oversampling strategy is improved by constructing a binary multi-label relationship for the load deviations in coal-fired units.Subsequently,an adaptive adjustment of the oversampling factor is implemented to determine the oversampling weight for each sample class.Finally,the generation of new instances is refined by dynamically evaluating the similarity between new cases and natural neighbors through a random factor,ensuring precise control over the instance generation process.In comparisons with nine benchmark methods across three imbalanced USC load deviation datasets,the proposed method demonstrates superior performance on several key evaluation metrics,including Micro-F1,Micro-G-mean,and Hamming Loss,with average values of 0.8497,0.9150,and 0.1503,respectively.These results substantiate the effectiveness of the proposed method in accurately diagnosing the sources of load deviations in USC units.展开更多
Reconstructing three-dimensional(3D)shapes from a single image remains a significant challenge in computer vision due to the inherent ambiguity caused by missing or occluded shape information.Previous studies have pre...Reconstructing three-dimensional(3D)shapes from a single image remains a significant challenge in computer vision due to the inherent ambiguity caused by missing or occluded shape information.Previous studies have predominantly focused on mesh models supervised by multi-view silhouettes.However,such methods are limited in reconstructing fine details.In this study,a 3D mesh model is predicted from a single image,leveraging depth consistency and without requiring viewpoint pose annotations.The model effectively learns strong shape priors that preserve finer structures and accurately predicts view poses from"correlation-supervised"viewpoints.Additionally,standard deviation and Laplacian losses were employed to regulate mesh edge distribution,resulting in more precise reconstructions.Differentiable renderer functions were derived from the 3D mesh to generate depth maps.Compared to conventional approaches,the proposed method provided superior representation of subtle structures.When applied to both synthetic and real-world datasets,the model outperformed existing methods in view-based 3D reconstruction tasks.展开更多
Traditional controlled source electromagnetic methods(CSEM)typically collect specific single-component of the total magnetic field intensity,leading to zero-value bands,narrow azimuthal detection ranges,and angular de...Traditional controlled source electromagnetic methods(CSEM)typically collect specific single-component of the total magnetic field intensity,leading to zero-value bands,narrow azimuthal detection ranges,and angular detections.An innovative detection strategy that utilized both the horizontal and total magnetic field intensities was introduced in this work.Numerical simulations were conducted to analyze the impact of sensor angular deviations on single-component and horizontal magnetic field intensities.Notably,the horizontal magnetic field intensity remains unaffected by horizontal angle deviations,while the total magnetic field shows resilience to all angular deviations.Theoretically,orthogonal magnetic sensors could facilitate wide-azimuth magnetic field detection.Results from field experiments revealed a pronounced anomaly response of both the horizontal and total magnetic field intensities to underground caverns.These experiments demonstrated a significant reduction in issues related to angular deviations in magnetic sensors and confirmed the feasibility of wide-azimuth magnetic field detection.The proposed wide-azimuth detection method has the potential to extend the detectable angle from that of CSEM to 360°,resolves the issue of angular deviation of magnetic sensors,and thus improves the detection accuracy.展开更多
The angular deviations and influential factors of Burgers orientation relationship(BOR)in Ti-6Al-4V and Ti-6.5Al-2Zr-1Mo-1V alloys were investigated by optical microscope(OM),scanning electron microscope(SEM),electron...The angular deviations and influential factors of Burgers orientation relationship(BOR)in Ti-6Al-4V and Ti-6.5Al-2Zr-1Mo-1V alloys were investigated by optical microscope(OM),scanning electron microscope(SEM),electron backscattered diffraction(EBSD)and high-angle annular dark-field scanning transmission electron microscope(HAADF-STEM).A spherical center angle model was introduced to calculate the angular deviations from the ideal BOR between α and β phases.The results indicate thatαand β phases in α colonies of both alloys do not follow the perfect BOR during β→α phase transformation,with angular deviation values less than 3°.Through detailed microstructure characterization,the broad face of α/β interfaces viewed along two different electron incident directions shows the atomic-scale terrace-ledge structure,and many dislocations are observed within α and β phases and near α/β interfaces.Further studies reveal that the angular deviations mainly originate from lattice distortions caused by dislocations in α and β phases and lattice mismatches at α/β interfaces.展开更多
The forecast results of temperature based on the intelligent grids of the Central Meteorological Observatory and the meteorological bureau of the autonomous region and the numerical forecast model of the European Cent...The forecast results of temperature based on the intelligent grids of the Central Meteorological Observatory and the meteorological bureau of the autonomous region and the numerical forecast model of the European Center(EC model)from February to December in 2022 were used.Based on the data of the national intelligent grid forecast,the intelligent grid forecast of the regional bureau,EC model,etc.,temperature was predicted.According to the research of the grid point forecast synthesis algorithm with the highest accuracy rate in the recent three days,the temperature grid point correction was conducted in two forms of stations and grids.In order to reduce the deviation caused by the seasonal system temperature difference,a temperature prediction model was established by using the rolling forecast errors of 5,10,15,20,25 and 30 d as the basis data.The verification and evaluation of objective correction results show that the accuracy rate of temperature forecast by the intelligent grid of the regional bureau,the national intelligent grid,and EC model could be increased by 10%,8%,and 12%,respectively.展开更多
The solar wind's interaction with the Moon has traditionally been understood through the Moon's absorption of solar wind particles and the formation of a plasma cavity on its nightside,known as the lunar wake....The solar wind's interaction with the Moon has traditionally been understood through the Moon's absorption of solar wind particles and the formation of a plasma cavity on its nightside,known as the lunar wake.This study reveals unexpected,large-scale perturbations in the solar wind upstream of the Moon,using 11 years of data from the OMNI and ARTEMIS(Acceleration,Reconnection,Turbulence and Electrodynamics of Moon's Interaction with the Sun)missions(2012-2023).We find systematic moonward deviations of~tens of km/s in a direction perpendicular to the solar wind(moonward),at altitudes of up to 1000 km,particularly when the interplanetary magnetic field(IMF)lines are oblique to the solar wind(30°<θ<60°)and connected to the lunar dayside.The longer the duration of the interaction,the greater the moonward deviation.These perturbations can be explained by neither solar wind pickup of the reflected ions,nor lunar wake dynamics.Instead,they appear to correlate with magnetic connectivity between the ARTEMIS probes and the lunar surface,suggesting a more complex solar wind interaction than previously thought.展开更多
The purpose of this article is to analyze the advantages and application paths of BIM5D technology in the cost control of completed houses.In the research phase,based on the reading of literature and the combination o...The purpose of this article is to analyze the advantages and application paths of BIM5D technology in the cost control of completed houses.In the research phase,based on the reading of literature and the combination of project materials,the advantages of BIM5D in the cost control project of completed houses are analyzed after introducing the cost control of completed houses and the connotation of BIM5D technology.Finally,this article starts from multiple perspectives,including BIM5D modeling,cost deviation analysis under dynamic cost control,etc.,and finally forms a relatively systematic and complete BIM cost control technology system.It is hoped that this article can provide technical reference value for China’s completed housing projects,promote the improvement of the project team’s cost control level,obtain considerable economic benefits based on completing project construction with quality and quantity,and enhance the competitiveness of enterprises.展开更多
AIM:To compare refractive error and angle of deviation in patients with basic esotropia and basic exotropia.METHODS:A retrospective review was conducted on the medical records of patients with basic-type strabismus.De...AIM:To compare refractive error and angle of deviation in patients with basic esotropia and basic exotropia.METHODS:A retrospective review was conducted on the medical records of patients with basic-type strabismus.Demographic data,refractive error,best-corrected distance visual acuity(BCVA),and the horizontal and vertical angle of deviation between basic esotropia and exotropia patients were compared.RESULTS:Among the 7129 patients(mean age 22.98±14.81y)evaluated,44.7%(3185 cases,54.9%male)exhibited basic-type esotropia,while 55.3%(3944 cases,53.9%male)presented with basic-type exotropia.Basic esotropia cases exhibited more hyperopic spherical equivalent measurements in both eyes(right:0.53±3.07 vs left:0.56±2.98 D)than those with basic exotropia(right eye:-0.33±2.84 vs left eye:-0.24±2.68 D,P<0.001 for both eyes).Patients with basic esotropia had significantly greater horizontal deviation angles(near:36.08±18.87 PD and far:35.56±18.75 PD)compared to those with basic exotropia(near:33.75±16.11 PD and far:33.26±15.90 PD,P<0.001).Conversely,patients with basic exotropia had slightly higher vertical deviation angles(near:1.67±5.80 PD and far:1.72±5.89 PD)compared to those with basic esotropia(near:1.12±4.57 PD and far:1.12±4.58 PD,P<0.001).Patients with basic esotropia underwent surgical intervention at younger ages compared to basic exotropia individuals(19.68±15.99 vs 25.66±13.20,P<0.001).CONCLUSION:Basic esotropia patients present more hyperopic refractive errors,better visual acuity,larger horizontal yet smaller vertical ocular misalignments,and tend to undergo strabismus surgery at younger ages relative to basic exotropia cases.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.52388102)the Sichuan Science and Technology Program (Grant No.2024NSFTD0011)the Fundamental Research Funds for the State Key Laboratory of Rail Transit Vehicle System of Southwest Jiaotong University (Grant No.2023TPL-T11)。
文摘Pitch deviation at rack joints(PDRJ) is a common error in rack railways. It directly affects the contact characteristics between the rack and gear and leads to accelerated surface wear. This threatens the stability and service life of the rack system, and the theoretical understanding of this issue remains limited. To address this gap, this study develops an improved tooth wear model that simultaneously accounts for the instantaneous variations in meshing stiffness and dynamic transmission error(DTE) induced by PDRJ, as well as the real-time correlation between gear-rack contact position and meshing excitation. Subsequently, the rack tooth load and wear characteristics are evaluated through the rack vehicle-track coupled dynamics and gear-rack contact model. The model's reliability is verified through field measurements. Moreover, the influence of varying PDRJ levels on load sharing factors, surface wear depth, and rack displacement is investigated. The results show that PDRJ disrupts the theoretical gear-rack meshing process, resulting in non-uniform load distribution and accelerated wear, particularly in the addendum and dedendum regions of the rack teeth. This study provides valuable insights into the rack surface wear mechanism under PDRJ.
基金supported by State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining&Technology,Beijing(Grant No.SKLGDUEK2120)。
文摘The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on the mechanical performance of anchor rods,with limited attention to the coupled evolution of strain and temperature fields during tensile deformation.This knowledge gap hinders a comprehensive understanding of the synergistic mechanical-thermal response mechanisms in anchor rods under loading conditions.To address this limitation,the present study systematically investigated the evolution of strain and temperature fields,along with their correlation,during the test of micro-negative Poisson's ratio(NPR)and ordinary Poisson's ratio(PR)anchor rods.Digital image correlation(DIC)and infrared thermography(IRT)techniques were employed for this exploration.The uniaxial tensile tests were conducted at two different rates,and the ordinary PR anchor rod(Q235 anchor rod)was established as a control group for comparative analysis.The findings reveal that the micro-NPR anchor rod exhibit strain localization at multiple locations during the tensile process,whereas Q235 anchors show local strain concentration in only one region.The standard deviation evolution curves for both the strain and temperature field exhibit two distinct phases in the two anchor rods.The evolution patterns between these two types of curves are basically consistent.The two standard deviation curves for the micro-NPR anchor rod display a wavy increase in the second phase,while for the Q235 anchor rod,they increase steadily until the specimen is damaged.The correlation analysis reveals that the standard deviations of strain and temperature differences for both types of anchor rods are significantly correlated.These findings demonstrate the synergistic evolution mechanism of deformation and thermal response,providing a potential foundation for utilizing thermal monitoring to assess the stability of rock support structures.
基金supported by the National Natural Science Foundation of China(Grant Nos.52378392,52408356)the Foal Eagle Program Youth Top-notch Talent Project of Fujian Province,China(Grant No.00387088).
文摘Although machine learning models have achieved high enough accuracy in predicting shield position deviations,their“black box”nature makes the prediction mechanisms and decision-making processes opaque,leading to weaker explanations and practicability.This study introduces a novel explainable deep learning framework comprising the Informer model with enhanced attention mechanisms(EAMInfor)and deep learning important features(DeepLIFT),aimed at improving the prediction accuracy of shield position deviations and providing interpretability for predictive results.The EAMInfor model attempts to integrate channel attention,spatial attention,and simple attention modules to improve the Informer model's performance.The framework is tested with the four different geological conditions datasets generated from the Xiamen metro line 3,China.Results show that the EAMInfor model outperforms the traditional Informer and comparison models.The analysis with the DeepLIFT method indicates that the push thrust of push cylinder and the earth chamber pressure are the most significant features,while the stroke length of the push cylinder demonstrated lower importance.Furthermore,the variation trends in the significance of data points within input sequences exhibit substantial differences between single and composite strata.This framework not only improves predictive accuracy but also strengthens the credibility and reliability of the results.
基金Supported by NSFC(Nos.11661025,12161024)Natural Science Foundation of Guangxi(Nos.2020GXNSFAA159118,2021GXNSFAA196045)+2 种基金Guangxi Science and Technology Project(No.Guike AD20297006)Training Program for 1000 Young and Middle-aged Cadre Teachers in Universities of GuangxiNational College Student's Innovation and Entrepreneurship Training Program(No.202110595049)。
文摘In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192].
基金sponsored by the National Natural Science Foundation of China[grant number U2442218]。
文摘Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimilation is quite challenging.This is because there is limited knowledge about the cross-component background error covariance(BEC)between LST and atmospheric state variables.This study aims to clarify whether there is a relationship between the error of LST and atmospheric variables,and whether this relationship varies spatially and temporally.To this end,the BEC coupled with atmospheric variables and LST was constructed(LST-BEC),and its characteristics were analyzed based on the 2023 mei-yu season.The general characteristics of LST-BEC show that the LST is mainly correlated with the atmospheric temperature and the correlation decreases gradually with a rise in atmospheric height,and the error standard deviation of the LST is noticeably larger than that of the low-level atmospheric temperature.The spatiotemporal characteristics of LST-BEC on the heavy-rain day and light-rain day show that the error correlation and error standard deviation of LST and low-level atmospheric temperature and humidity are closely related to the weather background,and also have obvious diurnal variations.These results provide valuable information for strongly coupled land-atmosphere assimilation.
基金Supported by State Grid Zhejiang Electric Power Co.,Ltd.Science and Technology Project Funding(No.B311DS230005).
文摘To address the issue of coordinated control of multiple hydrogen and battery storage units to suppress the grid-injected power deviation of wind farms,an online optimization strategy for Battery-hydrogen hybrid energy storage systems based on measurement feedback is proposed.First,considering the high charge/discharge losses of hydrogen storage and the low energy density of battery storage,an operational optimization objective is established to enable adaptive energy adjustment in the Battery-hydrogen hybrid energy storage system.Next,an online optimization model minimizing the operational cost of the hybrid system is constructed to suppress grid-injected power deviations with satisfying the operational constraints of hydrogen storage and batteries.Finally,utilizing the online measurement of the energy states of hydrogen storage and batteries,an online optimization strategy based on measurement feedback is designed.Case study results show:before and after smoothing the fluctuations in wind power,the time when the power exceeded the upper and lower limits of the grid-injected power accounted for 24.1%and 1.45%of the total time,respectively,the proposed strategy can effectively keep the grid-injected power deviations of wind farms within the allowable range.Hydrogen storage and batteries respectively undertake long-term and short-term charge/discharge tasks,effectively reducing charge/discharge losses of the Battery-hydrogen hybrid energy storage systems and improving its operational efficiency.
基金supported by the Key R&D Program of Zhejiang Province(Nos.2023C01166 and 2024SJCZX0046)the Zhejiang Provincial Natural Science Foundation of China(Nos.LDT23E05013E05 and LD24E050009)the Natural Science Foundation of Ningbo(No.2021J150),China.
文摘Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address this issue,we propose a geometric error cost sensitivity-based accuracy allocation method for five-axis machine tools.A geometric error model consisting of 4l error components is constructed based on homogeneous transformation matrices.Volumetric points with positional and tool direction deviations are randomly sampled to evaluate the accuracy of the machine tool.The sensitivity of each error component at these sampling points is analyzed using the Sobol method.To balance the needs of geometric precision and manufacturing cost,a geometric error cost sensitivity function is developed to estimate the required cost.By allocating error components affecting tool direction deviation first and the remaining components second,this allocation scheme ensures that both deviations meet the requirements.We also perform numerical simulation of a BC-type(B-axis and C-axis type)five-axis machine tool to validate the method.The results show that the new allocation scheme reduces the total geometric error cost by 27.8%compared to a uniform allocation scheme,and yields the same positional and tool direction machining accuracies.
基金funded by the National Natural Science Foundation of China(52079103)the Outstanding Youth Science Fund of Xi'an University of Science and Technology(2024YQ2-02).
文摘The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,causing carbon storage exchanges.However,the relationship between carbon storage and land use change in the MRYR is not concerned,which results in the uncertainty in the simulation of carbon storage in this area.Land use changes directly affect the carbon storage capacity of ecosystems,and as an indicator reflecting the overall state of land use,land use degree has an important relationship with carbon storage.In this study,land use data and the integrated valuation of ecosystem services and trade-offs(InVEST)model were used to assess the trends in land use degree and carbon storage in the MRYR during 1980-2020.The potential impact index and the standard deviation ellipse(SDE)algorithm were applied to quantify and analyze the characteristics of the impact of land use changes on carbon storage.Subsequently,land use transitions that led to carbon storage variations and their spatial variations were determined.The results showed that:(1)the most significant periods of carbon storage changes and land use transitions were observed during 1990-1995 and 1995-2020,with the most changed areas locating in the east of Fenhe River and in northwestern Henan Province;(2)the positive impact of land use degree on carbon storage may be related to the environmental protection measures implemented along the Yellow River,while the negative impact may be associated with the expansion of construction land in plain areas;and(3)the conversion of other land use types to grassland was the primary factor affecting carbon storage changes during 1980-2020.In future land use planning,attention should be given to the direction of grassland conversion,and focus on reasonably limiting the development of construction land.To enhance carbon storage,it will be crucial to increase the area of high-carbon-density land types,such as forest land and grassland under the condition that the area of permanent farmland does not decrease.
基金supported by the National Natural Science Foundation of China(Grant No.11671145)the Science and Technology Commission of Shanghai Municipality(Grant No.18dz2271000).
文摘In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are different from those of weak record numbers,which are interesting complements of the conclusions by Li and Yao[1].
基金Partially supported by NSFC(No.11701304)the K.C.Wong Education Foundation。
文摘In this paper we study the Freidlin-Wentzell's large deviation principle for the following nonlinear fractional stochastic heat equation driven by Gaussian noise∂/∂tu^(ε)=D_(δ)^(α)(t,x)+√εσ(u^(ε)(t,x))W(t,x),(t,x)∈[0,T]×R,where D_(δ)^(α)is a nonlocal fractional differential operator and W is the Gaussian noise which is white in time and behaves as a fractional Brownian motion with Hurst index H satisfying 3-α/4<H<1/2,in the space variable.The weak convergence approach plays an important role.
文摘In this paper,based on the structure-behavior coupling paradigm,we propose the concept of deviation of central town to describe the geography-market distance between farmers and the central regional town.Using the survey data from farmers in a poverty-stricken village in Western China,the impact of deviation of central town on farmers'livelihood strategies is analyzed.The results indicate that farmers exhibit spatial heterogeneity in their livelihood strategies.Those with low deviation show a strong inclination towards working in urban areas,while those with high deviation tend to integrate into rural industries.The deviation of central town influences farmers'livelihood strategies through the information effect,which is also affected by the level of rural infrastructure and public services,labor force structure and assistance policies.The obtained results are expected to provide guidance for promoting the integration of farmers into the urban-rural economic cycle based on sustainable livelihoods and connecting poverty alleviation with rural revitalization.
基金supported by the National Natural Science Foundation of China(Grant No.62173050)Shenzhen Municipal Science and Technology Innovation Committee(Grant No.KCXFZ20211020165004006)+3 种基金Natural Science Foundation of Hunan Province of China(Grant No.2023JJ30051)Hunan Provincial Graduate Student Research Innovation Project(Grant No.QL20230214)Major Scientific and Technological Innovation Platform Project of Hunan Province(2024JC1003)Hunan Provincial University Students’Energy Conservation and Emission Reduction Innovation and Entrepreneurship Education Center(Grant No.2019-10).
文摘Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispatching.Data-driven diagnostic methods often fail to account for the imbalanced distribution of data samples,leading to reduced classification performance in diagnosing load deviations in USC units.To address the class imbalance issue in USC load deviation datasets,this study proposes a diagnostic method based on the multi-label natural neighbor boundary oversampling technique(MLNaNBDOS).The method is articulated in three phases.Initially,the traditional binary oversampling strategy is improved by constructing a binary multi-label relationship for the load deviations in coal-fired units.Subsequently,an adaptive adjustment of the oversampling factor is implemented to determine the oversampling weight for each sample class.Finally,the generation of new instances is refined by dynamically evaluating the similarity between new cases and natural neighbors through a random factor,ensuring precise control over the instance generation process.In comparisons with nine benchmark methods across three imbalanced USC load deviation datasets,the proposed method demonstrates superior performance on several key evaluation metrics,including Micro-F1,Micro-G-mean,and Hamming Loss,with average values of 0.8497,0.9150,and 0.1503,respectively.These results substantiate the effectiveness of the proposed method in accurately diagnosing the sources of load deviations in USC units.
基金Supported by National Key Research and Development Program of China(Grant No.2024YFB3409800)Postdoctoral Fellowship Program of CPSF of China(Grant No.GZB20240940)China Postdoctoral Science Foundation(Grant Nos.2025T181108,2024M764127)。
文摘Reconstructing three-dimensional(3D)shapes from a single image remains a significant challenge in computer vision due to the inherent ambiguity caused by missing or occluded shape information.Previous studies have predominantly focused on mesh models supervised by multi-view silhouettes.However,such methods are limited in reconstructing fine details.In this study,a 3D mesh model is predicted from a single image,leveraging depth consistency and without requiring viewpoint pose annotations.The model effectively learns strong shape priors that preserve finer structures and accurately predicts view poses from"correlation-supervised"viewpoints.Additionally,standard deviation and Laplacian losses were employed to regulate mesh edge distribution,resulting in more precise reconstructions.Differentiable renderer functions were derived from the 3D mesh to generate depth maps.Compared to conventional approaches,the proposed method provided superior representation of subtle structures.When applied to both synthetic and real-world datasets,the model outperformed existing methods in view-based 3D reconstruction tasks.
基金financially supported by the National Key Research and Development Program of China(No.2022YFC2903704)the Hunan Provincial Science and Technology Innovation Program,China(No.2023RC1014)+1 种基金the Fundamental Research Funds for the Central Universities of Central South University,China(No.2023ZZTS0441)the Hunan Provincial Natural Science Foundation of China(Nos.2023JJ40222,2024AQ2002)。
文摘Traditional controlled source electromagnetic methods(CSEM)typically collect specific single-component of the total magnetic field intensity,leading to zero-value bands,narrow azimuthal detection ranges,and angular detections.An innovative detection strategy that utilized both the horizontal and total magnetic field intensities was introduced in this work.Numerical simulations were conducted to analyze the impact of sensor angular deviations on single-component and horizontal magnetic field intensities.Notably,the horizontal magnetic field intensity remains unaffected by horizontal angle deviations,while the total magnetic field shows resilience to all angular deviations.Theoretically,orthogonal magnetic sensors could facilitate wide-azimuth magnetic field detection.Results from field experiments revealed a pronounced anomaly response of both the horizontal and total magnetic field intensities to underground caverns.These experiments demonstrated a significant reduction in issues related to angular deviations in magnetic sensors and confirmed the feasibility of wide-azimuth magnetic field detection.The proposed wide-azimuth detection method has the potential to extend the detectable angle from that of CSEM to 360°,resolves the issue of angular deviation of magnetic sensors,and thus improves the detection accuracy.
基金supported by the National Natural Science Foundation of China(Nos.51971009,12002013,51831006)the Natural Science Foundation of Zhejiang Province,China(No.LZ23E010004).
文摘The angular deviations and influential factors of Burgers orientation relationship(BOR)in Ti-6Al-4V and Ti-6.5Al-2Zr-1Mo-1V alloys were investigated by optical microscope(OM),scanning electron microscope(SEM),electron backscattered diffraction(EBSD)and high-angle annular dark-field scanning transmission electron microscope(HAADF-STEM).A spherical center angle model was introduced to calculate the angular deviations from the ideal BOR between α and β phases.The results indicate thatαand β phases in α colonies of both alloys do not follow the perfect BOR during β→α phase transformation,with angular deviation values less than 3°.Through detailed microstructure characterization,the broad face of α/β interfaces viewed along two different electron incident directions shows the atomic-scale terrace-ledge structure,and many dislocations are observed within α and β phases and near α/β interfaces.Further studies reveal that the angular deviations mainly originate from lattice distortions caused by dislocations in α and β phases and lattice mismatches at α/β interfaces.
文摘The forecast results of temperature based on the intelligent grids of the Central Meteorological Observatory and the meteorological bureau of the autonomous region and the numerical forecast model of the European Center(EC model)from February to December in 2022 were used.Based on the data of the national intelligent grid forecast,the intelligent grid forecast of the regional bureau,EC model,etc.,temperature was predicted.According to the research of the grid point forecast synthesis algorithm with the highest accuracy rate in the recent three days,the temperature grid point correction was conducted in two forms of stations and grids.In order to reduce the deviation caused by the seasonal system temperature difference,a temperature prediction model was established by using the rolling forecast errors of 5,10,15,20,25 and 30 d as the basis data.The verification and evaluation of objective correction results show that the accuracy rate of temperature forecast by the intelligent grid of the regional bureau,the national intelligent grid,and EC model could be increased by 10%,8%,and 12%,respectively.
基金supported by the National Natural Science Foundation of China(Grant No.42474227,42241106,42388101)financial support through the German Ministry for Economy and Technology and the German Center for Aviation and Space(DLR)under contract 50 OC 0302
文摘The solar wind's interaction with the Moon has traditionally been understood through the Moon's absorption of solar wind particles and the formation of a plasma cavity on its nightside,known as the lunar wake.This study reveals unexpected,large-scale perturbations in the solar wind upstream of the Moon,using 11 years of data from the OMNI and ARTEMIS(Acceleration,Reconnection,Turbulence and Electrodynamics of Moon's Interaction with the Sun)missions(2012-2023).We find systematic moonward deviations of~tens of km/s in a direction perpendicular to the solar wind(moonward),at altitudes of up to 1000 km,particularly when the interplanetary magnetic field(IMF)lines are oblique to the solar wind(30°<θ<60°)and connected to the lunar dayside.The longer the duration of the interaction,the greater the moonward deviation.These perturbations can be explained by neither solar wind pickup of the reflected ions,nor lunar wake dynamics.Instead,they appear to correlate with magnetic connectivity between the ARTEMIS probes and the lunar surface,suggesting a more complex solar wind interaction than previously thought.
文摘The purpose of this article is to analyze the advantages and application paths of BIM5D technology in the cost control of completed houses.In the research phase,based on the reading of literature and the combination of project materials,the advantages of BIM5D in the cost control project of completed houses are analyzed after introducing the cost control of completed houses and the connotation of BIM5D technology.Finally,this article starts from multiple perspectives,including BIM5D modeling,cost deviation analysis under dynamic cost control,etc.,and finally forms a relatively systematic and complete BIM cost control technology system.It is hoped that this article can provide technical reference value for China’s completed housing projects,promote the improvement of the project team’s cost control level,obtain considerable economic benefits based on completing project construction with quality and quantity,and enhance the competitiveness of enterprises.
文摘AIM:To compare refractive error and angle of deviation in patients with basic esotropia and basic exotropia.METHODS:A retrospective review was conducted on the medical records of patients with basic-type strabismus.Demographic data,refractive error,best-corrected distance visual acuity(BCVA),and the horizontal and vertical angle of deviation between basic esotropia and exotropia patients were compared.RESULTS:Among the 7129 patients(mean age 22.98±14.81y)evaluated,44.7%(3185 cases,54.9%male)exhibited basic-type esotropia,while 55.3%(3944 cases,53.9%male)presented with basic-type exotropia.Basic esotropia cases exhibited more hyperopic spherical equivalent measurements in both eyes(right:0.53±3.07 vs left:0.56±2.98 D)than those with basic exotropia(right eye:-0.33±2.84 vs left eye:-0.24±2.68 D,P<0.001 for both eyes).Patients with basic esotropia had significantly greater horizontal deviation angles(near:36.08±18.87 PD and far:35.56±18.75 PD)compared to those with basic exotropia(near:33.75±16.11 PD and far:33.26±15.90 PD,P<0.001).Conversely,patients with basic exotropia had slightly higher vertical deviation angles(near:1.67±5.80 PD and far:1.72±5.89 PD)compared to those with basic esotropia(near:1.12±4.57 PD and far:1.12±4.58 PD,P<0.001).Patients with basic esotropia underwent surgical intervention at younger ages compared to basic exotropia individuals(19.68±15.99 vs 25.66±13.20,P<0.001).CONCLUSION:Basic esotropia patients present more hyperopic refractive errors,better visual acuity,larger horizontal yet smaller vertical ocular misalignments,and tend to undergo strabismus surgery at younger ages relative to basic exotropia cases.
