This paper presents a Three-Dimensional(3D)cooperative guidance law with Practical Predefined-Time(PPT)convergence for multiple missiles considering approach angle(terminal lineof-sight)and simultaneous arrival constr...This paper presents a Three-Dimensional(3D)cooperative guidance law with Practical Predefined-Time(PPT)convergence for multiple missiles considering approach angle(terminal lineof-sight)and simultaneous arrival constraints.To achieve a salvo attack against a maneuvering target from various directions,the guidance problem is tackled by addressing two critical factors:ensuring that the time-of-arrival is consistent and that the desired approach angles can be met.Considering the short duration of the homing guidance process,the convergence with predefined time for guidance states(especially the approach angle and time-to-go)is factored in.First,for the simultaneous arrival,a PPT guidance law is developed,which can meet the same time-to-go convergence rate in the Line-of-Sight(LOS)direction.Then,in the normal LOS direction,a 3D PPT guidance law is presented considering the approach angle constraint so that the desired approach angles can be reached within a user-designed time.The time-based generator technique is employed in the proposed PPT Cooperative Guidance Law(PPTCGL)to avoid the time-varying gain singularity issue.Notably,this technique can allow the convergence time to be preset in advance,independent of initial system conditions and tuning parameters.Additionally,to avoid excessive gain and improve the robustness of guidance law,a PPT disturbance observer is designed against uncertainties and target maneuvers so that the guidance system perturbation can be compensated in real time.It is userfriendly that the convergence of disturbance estimation can be met with a flexible pre-setting time before achieving the terminal guidance constraints.Finally,extensive numerical simulations are conducted to verify the effectiveness and robustness of the proposed PPTCGL in both the nominal cases and the Monte Carlo test.展开更多
Transformers have been widely applied to hyperspectral image classification,leveraging their self-attention mechanism for powerful global modelling.However,two key challenges remain as follows:excessive memory and com...Transformers have been widely applied to hyperspectral image classification,leveraging their self-attention mechanism for powerful global modelling.However,two key challenges remain as follows:excessive memory and computational costs from calculating correlations between all tokens(especially as image size or spectral bands increase)and limited ability to model local boundary information due to lacking explicit enhancement mechanisms.This paper proposes a novel method,bridge transformer network fused with deep graph convolution(BTDGC),to address these issues.The framework includes three components as follows:a double random masking mechanism(DRMM)that forces the model to infer masked features from context during training,a bridge transformer(BT)module with bridge tokens for cross-region feature interaction and a Deep Graph Convolutional Pooling(DGCP)module that preserves spatial topology while aggregating hierarchical information.Experiments on standard hyperspectral datasets show BTDGC outperforms mainstream methods in classification accuracy and robustness,effectively balancing global modelling and local boundary representation.The code is available at http://gffzz188fe103f8f1460asnvfxbkvkp9cc609o.ffgz.tsg.suse.edu.cn/jenny3489/BTDGC.展开更多
Dear Editor,This letter presents a novel graph neural network, namely modularized graph convolution network(MGCN), to address the underexplored issue in graph convolution networks(GCNs), wherein the weights for neighb...Dear Editor,This letter presents a novel graph neural network, namely modularized graph convolution network(MGCN), to address the underexplored issue in graph convolution networks(GCNs), wherein the weights for neighbor aggregation are fixed, leading to the limited capability of capturing diverse relationships among nodes for representation learning. Conventional GCNs always learn node representations in the graph according to the weights computed from the graph Laplacian, consequently overlooking the similarity and group cohesiveness of node features.展开更多
Aerial surveys are dynamic and continuous processes,and there are different height distributions of the ground in the measurement area,which leads to problems such as overlapping measurement areas and inaccurate altit...Aerial surveys are dynamic and continuous processes,and there are different height distributions of the ground in the measurement area,which leads to problems such as overlapping measurement areas and inaccurate altitude correction during the survey process.Commonly used terrain correction methods are based on the concept of finite elementization of ground surface radioactive sources,using GPS coordinates,radar altitude,and ground elevation distribution information from aerial surveys,combined with the sourceless efficiency calibration method to construct a response matrix,which is then inverted for surface nuclide content.However,most of the sourceless efficiency calibration methods used are numerical calculations that consider the body detector as a point detector and do not consider the changes in intrinsic detection efficiency under different incident directions of gamma rays.Therefore,when the altitude of the measurement area varies significantly or the flight altitude of the aerial survey is relatively low,such sourceless efficiency calibration method calculations tend to have a large bias,which affects the accuracy of the terrain correction.To address the above problems,this study employs a novel sourceless efficiency calibration method based on the Boolean operation of the ray deposition process and simplifies the traditional body source measurement model to a surface source measurement model to achieve fast and accurate efficiency calibration.Then,through the discretization of the measurement process,the static measurement process is superposed as equivalent to the dynamic measurement process,and the dynamic measurement response matrix is built and optimized based on the calibration method.Finally,the PSO-MLEM algorithm was used to solve the dynamic measurement response matrix to achieve dynamic terrain correction of aerial survey data.Analysis of the Baiyun'ebo test area revealed that,after applying dynamic terrain correction,the inverted anomalies in uranium(eU),thorium(eTh),and potassium(K)concentrations were closer to ground measurements(within 5.72%-30.79%)and exhibited clearer anomaly boundaries compared to traditional height-based corrections.However,owing to the inherent statistical fluctuations and characteristics of matrix inversion,higher measurement values tend to absorb lower ones,potentially enlarging the anomalous regions.Nevertheless,the highanomaly regions after inversion largely coincided with the ground truth validation,demonstrating that the proposed method can effectively correct airborne gamma spectrometry data.展开更多
This study explores the three-dimensional(3-D)characteristics of oceanic eddies in the Southern Ocean from 2021 to 2023.Copernicus Marine Environment Monitoring Service(CMEMS)GLORYS12V1 product,which provides daily cu...This study explores the three-dimensional(3-D)characteristics of oceanic eddies in the Southern Ocean from 2021 to 2023.Copernicus Marine Environment Monitoring Service(CMEMS)GLORYS12V1 product,which provides daily current field data at a(1/12)°grid resolution,is used to identify eddies with radii>10 km.Additionally,the daily sea level anomaly product from Haiyang-2(HY-2)altimeters is used to detect mesoscale eddies with radii>40 km.GLORYS12V1 detects over ten times more surface eddies than HY-2,likely due to its higher spatial and temporal resolution,which allows better identification of smaller-scale features.Both eddy radius and eddy kinetic energy(EKE)differences between layers decrease with depth.At 0.5 m,EKE is lower than at 300–600 m,where it stabilizes.Over 90%of eddies at these depths show center deflection angles under 3°,defined as the angular offset between eddy centers in adjacent layers relative to the vertical(0°)axis.In a 3-D eddy,the center may shift with depth due to physical processes,causing non-zero center deflection angles between layers.Below 300 m,eddy radius differences are more frequently under 20 km than in the upper 0.5–300 m,where baroclinic instability amplifies,and barotropic instability suppresses cross-layer variability.The influence of both instabilities weakens with depth.In the upper ocean(0.5–300 m),baroclinic instability increases the angular offsets between eddy centers.In contrast,barotropic instability reduces these offsets.At 300–600 m,both promote better vertical alignment,indicating greater structural stability.Overall,this study enhances the understanding of the vertical structure and dynamics of oceanic eddies in the Southern Ocean.展开更多
To accelerate the development and utilization of fusion energy,the China Fusion Engineering Test Reactor(CFETR)has been proposed as a bridge between the International Thermonuclear Experimental Reactor and demonstrati...To accelerate the development and utilization of fusion energy,the China Fusion Engineering Test Reactor(CFETR)has been proposed as a bridge between the International Thermonuclear Experimental Reactor and demonstration fusion reactors.The primary objective of the CFETR is to achieve fusion energy transformation and tritium self-sufficiency,which is realized through the function of the blanket.In this study,a neutronicshermal-hydraulics/mechanics coupling method is developed and applied to a helium-cooled ceramic breeder(HCCB)blanket,which is one of the two blanket candidates for the CFETR.A three-dimensional full-scale model is utilized in the coupling analysis to obtain the distributions of the neutronic,thermal-hydraulic,and mechanical parameters.A structural assessment of the CFETR HCCB blanket is then conducted considering steady-state conditions and two transient scenarios.The results demonstrate that following optimization of the blanket structure,the maximum temperatures of the different components remain below the safety limit of the corresponding materials.The structural assessment indicates that the blanket maintains its structural integrity under steady-state conditions.However,immediately after an in-box loss-of-coolant accident,structural failure owing to stress concentration may occur.Additionally,in the early stage of a loss-of-flow accident,the stress at the joint point between the cooling plate and cap exceeds the allowable stress of the material,potentially leading to structural failure within 17 s if no protective response is implemented.These findings provide comprehensive insights into the performance and safety of the CFETR HCCB blanket design.展开更多
The creation of a three-dimensional(3D)geological model plays a crucial guiding role in engineering.However,in practice,due to the sparsity of boreholes and the invisibility of strata,accurately reconstructing a 3D ge...The creation of a three-dimensional(3D)geological model plays a crucial guiding role in engineering.However,in practice,due to the sparsity of boreholes and the invisibility of strata,accurately reconstructing a 3D geological model has always been a challenging task.In this study,a data-and knowledge-driven 3D geological reconstruction method is proposed,where the Inverse Distance Weighting(IDW)method is integrated with computer vision techniques to improve the accuracy and reliability of geological modeling.The reconstruction of the geological model is realized by the reconstruction of continuous cross-sections in one direction.The reconstruction method integrates two deep learning models:a repair model that learns stratigraphic relationships from borehole data to reconstruct cross-sections,and an interpolation model that predicts intermediate sections by capturing stratigraphic distribution and variation patterns.The comparison with the IDW method and the ordinary kriging method on the virtual data verifies that the proposed method can capture the spatial distribution characteristics of the strata.An engineering example proves that the proposed method can be successfully applied to complex stratum modeling.The proposed method enhances and facilitates intuitive observation of both the reconstructed results and their uncertainties.The proposed method can provide guidance for underground engineering construction sites and contribute to their digital transformation.展开更多
The numerical manifold method,extensively utilized in numerical computations,faces significant challenges in generating complex manifold elements,particularly for three-dimensional applications.To overcome this challe...The numerical manifold method,extensively utilized in numerical computations,faces significant challenges in generating complex manifold elements,particularly for three-dimensional applications.To overcome this challenge,the meshfree numerical manifold method is developed by integrating the moving least-squares method into the numerical manifold method,effectively bypassing the need for meshing complex geometric objects.However,the implementation of the moving least-squares method introduces computational efficiency issues.To mitigate these,parallel computing methods have been incorporated,resulting in a tenfold increase in the speed of assembling the stiffness matrix with central processing unit parallelism,and a twentyfold increase with graphics processing unit parallelism.The static mechanical system equations for the meshfree numerical manifold method are derived using the Galerkin method.The method’s effectiveness and accuracy are then validated through a series of numerical experiments.The experiments demonstrated that the meshfree numerical manifold method achieves a high precision with minimal nodes and integration points.Additionally,positioning nodes outside the domain significantly improves computational accuracy at the boundaries.展开更多
Dear Editor,D2This letter presents a node feature similarity preserving graph convolutional framework P G.Graph neural networks(GNNs)have garnered significant attention for their efficacy in learning graph representat...Dear Editor,D2This letter presents a node feature similarity preserving graph convolutional framework P G.Graph neural networks(GNNs)have garnered significant attention for their efficacy in learning graph representations across diverse real-world applications.展开更多
Video emotion recognition is widely used due to its alignment with the temporal characteristics of human emotional expression,but existingmodels have significant shortcomings.On the one hand,Transformermultihead self-...Video emotion recognition is widely used due to its alignment with the temporal characteristics of human emotional expression,but existingmodels have significant shortcomings.On the one hand,Transformermultihead self-attention modeling of global temporal dependency has problems of high computational overhead and feature similarity.On the other hand,fixed-size convolution kernels are often used,which have weak perception ability for emotional regions of different scales.Therefore,this paper proposes a video emotion recognition model that combines multi-scale region-aware convolution with temporal interactive sampling.In terms of space,multi-branch large-kernel stripe convolution is used to perceive emotional region features at different scales,and attention weights are generated for each scale feature.In terms of time,multi-layer odd-even down-sampling is performed on the time series,and oddeven sub-sequence interaction is performed to solve the problem of feature similarity,while reducing computational costs due to the linear relationship between sampling and convolution overhead.This paper was tested on CMU-MOSI,CMU-MOSEI,and Hume Reaction.The Acc-2 reached 83.4%,85.2%,and 81.2%,respectively.The experimental results show that the model can significantly improve the accuracy of emotion recognition.展开更多
Considering the complexities of gas-water relationships in the gas reservoirs,unclear natural gas distribution and difficult exploration expansion of the Sinian–Permian natural gas in the Penglai gas area of the cent...Considering the complexities of gas-water relationships in the gas reservoirs,unclear natural gas distribution and difficult exploration expansion of the Sinian–Permian natural gas in the Penglai gas area of the central Sichuan Basin,this study investigates the gas source,charging processes and enrichment patterns of gas reservoirs based on reservoir characterization,natural gas geochemical analysis,reservoir testing,well logging-seismic data interpretation,as well as basin modeling and dynamic analysis.The results are obtained in three aspects.First,four sets of highly efficient source rocks are developed beneath the salt of the Triassic Jialingjiang Formation,dominated by the Cambrian source rocks.The reservoirs exhibit strong heterogeneity,with six sets of effective reservoirs being isolated from each other yet dynamically connected.Multi-stage strike-slip fault-related fault-fracture-cavity-unconformity systems constitute the hydrocarbon migration network.Second,overpressure generated by hydrocarbon generation in the Cambrian source rocks drove bidirectional hydrocarbon expulsion from the source kitchen.Multiple sources,including cracked gas from paleo-oil reservoirs and residual hydrocarbons within source rocks,contributed to the hydrocarbon supply.The Sinian–Permian system underwent multiple dynamic hydrocarbon accumulation processes,resulting in the formation of extensive“sweet spots”within multi-layered heterogeneous reservoirs,which were subsequently modified by late-stage gas adjustments to their current form.Third,a three-dimensional accumulation model for deep marine natural gas is established,with multi-source hydrocarbon supply,three-dimensional migration,multi-stage accumulation,dynamic adjustment and lithology-controlled distribution.Large-scale reservoirs within positive structural settings,late-stage structurally stable areas,and slope structures are identified as favorable plays for gas exploration.展开更多
Image captioning,a pivotal research area at the intersection of image understanding,artificial intelligence,and linguistics,aims to generate natural language descriptions for images.This paper proposes an efficient im...Image captioning,a pivotal research area at the intersection of image understanding,artificial intelligence,and linguistics,aims to generate natural language descriptions for images.This paper proposes an efficient image captioning model named Mob-IMWTC,which integrates improved wavelet convolution(IMWTC)with an enhanced MobileNet V3 architecture.The enhanced MobileNet V3 integrates a transformer encoder as its encoding module and a transformer decoder as its decoding module.This innovative neural network significantly reduces the memory space required and model training time,while maintaining a high level of accuracy in generating image descriptions.IMWTC facilitates large receptive fields without significantly increasing the number of parameters or computational overhead.The improvedMobileNet V3 model has its classifier removed,and simultaneously,it employs IMWTC layers to replace the original convolutional layers.This makes Mob-IMWTC exceptionally well-suited for deployment on lowresource devices.Experimental results,based on objective evaluation metrics such as BLEU,ROUGE,CIDEr,METEOR,and SPICE,demonstrate that Mob-IMWTC outperforms state-of-the-art models,including three CNN architectures(CNN-LSTM,CNN-Att-LSTM,CNN-Tran),two mainstream methods(LCM-Captioner,ClipCap),and our previous work(Mob-Tran).Subjective evaluations further validate the model’s superiority in terms of grammaticality,adequacy,logic,readability,and humanness.Mob-IMWTC offers a lightweight yet effective solution for image captioning,making it suitable for deployment on resource-constrained devices.展开更多
Accurate modeling of ship magnetic fields is important for predicting their spatial distribution to improve the magnetic stealth effect of ships.This study proposes an extrapolation model for ship magnetic fields base...Accurate modeling of ship magnetic fields is important for predicting their spatial distribution to improve the magnetic stealth effect of ships.This study proposes an extrapolation model for ship magnetic fields based on genetic algorithms and convolutional neural networks(CNNs).The magnetic probe position matrix of the traditional equivalent source is utilized as input,and the three-directional components of the magnetic field measured by the probes are employed as output.The extrapolation model for ship magnetic fields is obtained through iterative training and fitting with CNNs.Variables such as the number of magnetic dipoles,the distance between magnetic dipoles,the size and quantity of convolutional kernels,batch size,learning rate,and L2 regularization coefficient are optimized to boost the accuracy of the extrapolation model for magnetic fields.The fitting accuracy of the extrapolation model for ship magnetic fields is used as the optimization objective.Based on a finite element simulation model of ship magnetic fields,the accuracy and robustness of the CNN algorithm under different magnetic field conditions are validated using the known standard depth plane,the unknown depth at 1.125 times the standard depth plane,and the unknown depth at 1.25 times the standard depth plane.Results show that,after optimization,the fitting error for the magnetic field extrapolation model based on CNN is 1.50%for the standard depth plane,1.63%for the unknown depth at 1.125 times the standard depth plane,and 2.36%for the unknown depth at 1.25 times the standard depth plane.The error remains below 5%under varying magnetic field conditions.When a random measurement error of 0%-5%is introduced for the magnetic probes,the prediction error at 1.25 times the standard depth plane is 2.30%;with a random error of 0%-10%,the prediction error is 4.95%.This approach significantly improves the accuracy and robustness of magnetic field extrapolation,which makes it an effective and feasible method for ship magnetic field modeling.展开更多
Traffic flow prediction is of great importance in traffic planning,road resource management,and congestion mitigation.However,existing prediction have significant limitations in modeling multi-scale spatial-temporal f...Traffic flow prediction is of great importance in traffic planning,road resource management,and congestion mitigation.However,existing prediction have significant limitations in modeling multi-scale spatial-temporal features,particularly in capturing temporal periodicity and spatial dependency in dynamically evolving traffic networks.This paper proposes a novel framework of traffic flow prediction,referred to as Adaptive Graph Fusion Dual-scale Convolutional Network(AGFDCN),which integrates spatial-temporal dynamic graphs with dual-scale convolutional networks.Specifically,we introduce a Dual-Scale Temporal Network,which combines long-and short-term dilated causal convolutions with a temporal decay-aware attention mechanism to efficiently capture traffic patterns across multiple temporal scales.Furthermore,we design a Dynamic Adaptive Graph Module,which models complex spatial dependencies in traffic networks through an adaptive graph fusion mechanism and a dual-path attention-gated module.Finally,the temporal and spatial representations are integrated by employing a gated fusion mechanism,enhancing the overall prediction performance.Experimental results obtained based on three highway datasets(i.e.,PEMS04,PEMS07 and PEMS08)verify that the proposed model outperforms several state-of-the-art baselines in various evaluation metrics.Compared to the spatial-temporal graph model AGCRN with best performance in the baseline models,the proposed model exhibits significant improvements across all datasets:it achieves reduces of MAE by 42.07%and RMSE by 35.43%on PEMS04;MAE by 28.35%and RMSE by 29.28%on PEMS07;and MAE by 30.52%and RMSE by 30.73%on PEMS08,respectively,validating its effectiveness in modeling complex spatial-temporal traffic data and its robustness in handling sudden traffic changes.展开更多
The prediction of sea surface partial pressure of carbon dioxide(pCO2)in the South China Sea is crucial for understanding the region’s contribution to the global carbon budget and its interactions with climate cha...The prediction of sea surface partial pressure of carbon dioxide(pCO2)in the South China Sea is crucial for understanding the region’s contribution to the global carbon budget and its interactions with climate change.We applied the Spatiotemporal Convolutional Long Short-Term Memory(STConvLSTM)model,integrating key environmental factors including sea surface temperature(SST),sea surface salinity(SSS),and chlorophyll a(Chl a),to predict and analyze sea surface pCO2in the South China Sea.The model demonstrated high accuracy in short-term predictions(1 month),with a mean absolute error(MAE)of 0.394,a root mean square error(RMSE)of 0.659,and a coefficient of determination(R2)of 0.998.For long-term predictions(12 months),the model maintained its predictive capability,with an MAE of 0.667,RMSE of 1.255,and R2of 0.994.Feature importance analysis revealed that sea surface pCO2and SST were the main drivers of the model’s predictions,whereas Chl a and SSS had relatively minor impacts.The model’s generalization ability was further validated in the northwest Pacific Ocean and tropical Pacific Ocean,where it successfully captured the spatiotemporal variation in pCO2with small prediction errors.The ST-ConvLSTM model provides an efficient and accurate tool for forecasting and analyzing sea surface pCO2in the South China Sea,offering new insights into global carbon cycling and climate change.This study demonstrates the potential of deep learning in marine science and provides a significant technical support for global changes and marine ecosystem research.展开更多
Traffic holographic perception refers to the real-time,high-fidelity,and multi-dimensional sensing of traffic states through the fusion of heterogeneous sensors,including cameras,radars,and connected vehicle data.The ...Traffic holographic perception refers to the real-time,high-fidelity,and multi-dimensional sensing of traffic states through the fusion of heterogeneous sensors,including cameras,radars,and connected vehicle data.The multi-source perception data obtained thereby can provide a complete digital representation of the road network for the Intelligent Transportation System(ITS).However,sensors are vulnerable to environmental interference,which can result in data loss at specific points or along arterial highways for certain periods,potentially undermining system safety and decision-making reliability.To address these challenges,a deep learning method based on Graph Convolutional Networks(GCN)and Gated Recurrent Units(GRU)is proposed,leveraging Artificial Intelligence(AI)and intelligent connected technologies for real-time acquisition of multi-sensor perception data.A feature-level fusion integrates multi-source perception data.GCN captures spatial dependencies from the road network topology,while GRU extracts temporal features from time series,enabling accurate imputation of missing traffic data.The method is evaluated at intelligent connected intersections in the Beijing High-level Autonomous Driving Demonstration Area.Results show that the accuracy of long-term traffic state completion reaches 89.36%,and the Root Mean Square Error(RMSE)is reduced by 17.2%compared to the Long Short-Term Memory(LSTM)baseline.This framework provides a practical solution for deploying traffic holographic perception technology in secure and trustworthy ITS.展开更多
The time-dependent failure of surrounding rock in deep engineering is essentially controlled by the evolution of microcracks,with the pre-existing fracturing state induced by excavation playing a crucial role in the s...The time-dependent failure of surrounding rock in deep engineering is essentially controlled by the evolution of microcracks,with the pre-existing fracturing state induced by excavation playing a crucial role in the subsequent time-dependent fracturing process.From the perspective of microcrack development,it is a continuous,dynamic process.Therefore,taking the microcrack propagation process as the fundamental principle,this paper proposes a novel three-dimensional(3D)time-dependent model for hard rock that can depict the entire fracturing process within a unified theoretical framework.This developed model discards the traditional tri-modal partition method based on deformation,and instead adopts an analysis approach centred on time-dependent tensile and shear fracturing.The results show that the time-dependent deformation of hard rock is the macroscopic manifestation of the progressive evolution of microcracks over time.Under true triaxial stress,the growth tendency of cracks in hard rock is orientation-dependent throughout the entire loading process.This developed model provides a mechanical explanation for key time-dependent fracture characteristics observed in true triaxial creep tests,including the anisotropy of time-dependent deformation and the preferred orientation of macroscopic failure plane,and provides a novel framework for elucidating the time-dependent failure process of hard rock.展开更多
Methane in situ multistage explosive fracturing(MISMEF)presents a promising technique for enhancing complex fracture networks in deep,low-permeability shale reservoirs.This study employed highfidelity3D simulations,in...Methane in situ multistage explosive fracturing(MISMEF)presents a promising technique for enhancing complex fracture networks in deep,low-permeability shale reservoirs.This study employed highfidelity3D simulations,integrating a characteristic methane–oxygen explosion load model with dynamic relaxation and full-restart methods,to elucidate the coupled interactions between explosive loading and in situ stress.A damage-based zoning approach was developed to quantify fracture characteristics,leading to the proposal of a novel dimensionless evaluation index,Fmef.Results showed that in situ stress predominantly suppressed longitudinal fracture growth,while multistage loading effectively enhanced both lateral and longitudinal propagation following a"delayed initiation–accelerated propagation"pattern.Fracture volume exhibited nonlinear amplificationwith increasing stages,and the continuous increase in fractal dimension suggested improved network connectivity.Energy redistribution driven by the coupled effects of in situ stress and staged loading promoted complex network formation near the wellbore,with MISMEF progressively reducing fracture thresholds through rock mass weakening.Fmef analysis confirmedsignificantimprovement in fracture network quality across all stress conditions,particularly under medium to high in situ stress.This work provides critical mechanistic insights and a theoretical foundation for optimizing MISMEF in deep shale reservoir stimulation.展开更多
Convolutional neural networks(CNNs)have shown remarkable success across numerous tasks such as image classification,yet the theoretical understanding of their convergence remains underdeveloped compared to their empir...Convolutional neural networks(CNNs)have shown remarkable success across numerous tasks such as image classification,yet the theoretical understanding of their convergence remains underdeveloped compared to their empirical achievements.In this paper,the first filter learning framework with convergence-guaranteed learning laws for end-to-end learning of deep CNNs is proposed.Novel update laws with convergence analysis are formulated based on the mathematical representation of each layer in convolutional neural networks.The proposed learning laws enable concurrent updates of weights across all layers of the deep convolutional neural network and the analysis shows that the training errors converge to certain bounds which are dependent on the approximation errors.Case studies are conducted on benchmark datasets and the results show that the proposed concurrent filter learning framework guarantees the convergence and offers more consistent and reliable results during training with a trade-off in performance compared to stochastic gradient descent methods.This framework represents a significant step towards enhancing the reliability and effectiveness of deep convolutional neural network by developing a theoretical analysis which allows practical implementation of the learning laws with automatic tuning of the learning rate to guarantee the convergence during training.展开更多
BACKGROUND Laparoscopic sleeve gastrectomy(LSG)is currently the most commonly performed bariatric surgery owing to its effective weight loss and low complication rates.Nonetheless,some patients experience weight regai...BACKGROUND Laparoscopic sleeve gastrectomy(LSG)is currently the most commonly performed bariatric surgery owing to its effective weight loss and low complication rates.Nonetheless,some patients experience weight regain or insufficient weight loss due to residual gastric dilation,the factors of which remain unclear.AIM To evaluate changes in residual gastric volume after LSG using three-dimensional computed tomography reconstruction and to investigate the factors contributing to gastric dilation.METHODS This retrospective study included 50 patients who underwent LSG.Preoperative clinical and laboratory data were obtained.The residual gastric volume was measured using three-dimensional computed tomography reconstruction at 1 month and 3 months postoperatively.The total sleeve volume,tube volume,antral volume,and tube-to-antral volume ratio were also assessed.Resected gastric volume and staple line length were measured during surgery.Weight metrics and laboratory indices were recorded at 1 month,3 months,6 months,and 12 months postoperatively.The Eating Behavior After Bariatric Surgery Questionnaire and Gastroesophageal Reflux Disease Questionnaire(GERD-Q)were used to assess the dietary behavior of patients after LSG.Correlation between the degree of residual gastric dilation and percent total weight loss(%TWL)at 12 months postoperatively was analyzed.Univariate and multivariate correlation analyses were conducted to identify risk factors for residual gastric dilation after LSG.RESULTS The 50 included patients had a mean preoperative body mass index of 42.27±7.19 kg/m2 and average%TWL of 34%±7%at 1 year after LSG.At 1 month after LSG,the mean tube volume,antral volume,and total sleeve volume were 45.93±16.75 mL,115.85±44.92 mL,and 161.77±55.37 mL,respectively.At 3 months after LSG,the residual gastric volume showed statistically significant dilation(average dilation degree:13.50%±17.35%).%TWL at 1 year significantly correlated with residual gastric dilation(P<0.05).Univariate and multivariate linear regression analyses revealed that preoperative type 2 diabetes,residual gastric volume at 1 month after LSG,and GERD-Q scores were independent risk factors influencing the degree of residual gastric dilation.CONCLUSION In conclusion,residual gastric dilation after LSG significantly affected the efficacy of weight loss.Preoperative type 2 diabetes,residual gastric volume at 1 month after LSG,and GERD-Q scores were independent risk factors affecting the degree of residual gastric dilation.展开更多
基金supported by the National Natural Science Foundation of China(No.62573024)the Beijing Natural Science Foundation of China(No.4242041)+1 种基金the Fundamental Research Funds for the Central Universities of Chinathe Project of National Key Laboratory of Unmanned Aerial Vehicle Technology in Northwestern Polytechnical University,China(No.WR202404)。
摘要This paper presents a Three-Dimensional(3D)cooperative guidance law with Practical Predefined-Time(PPT)convergence for multiple missiles considering approach angle(terminal lineof-sight)and simultaneous arrival constraints.To achieve a salvo attack against a maneuvering target from various directions,the guidance problem is tackled by addressing two critical factors:ensuring that the time-of-arrival is consistent and that the desired approach angles can be met.Considering the short duration of the homing guidance process,the convergence with predefined time for guidance states(especially the approach angle and time-to-go)is factored in.First,for the simultaneous arrival,a PPT guidance law is developed,which can meet the same time-to-go convergence rate in the Line-of-Sight(LOS)direction.Then,in the normal LOS direction,a 3D PPT guidance law is presented considering the approach angle constraint so that the desired approach angles can be reached within a user-designed time.The time-based generator technique is employed in the proposed PPT Cooperative Guidance Law(PPTCGL)to avoid the time-varying gain singularity issue.Notably,this technique can allow the convergence time to be preset in advance,independent of initial system conditions and tuning parameters.Additionally,to avoid excessive gain and improve the robustness of guidance law,a PPT disturbance observer is designed against uncertainties and target maneuvers so that the guidance system perturbation can be compensated in real time.It is userfriendly that the convergence of disturbance estimation can be met with a flexible pre-setting time before achieving the terminal guidance constraints.Finally,extensive numerical simulations are conducted to verify the effectiveness and robustness of the proposed PPTCGL in both the nominal cases and the Monte Carlo test.
摘要Transformers have been widely applied to hyperspectral image classification,leveraging their self-attention mechanism for powerful global modelling.However,two key challenges remain as follows:excessive memory and computational costs from calculating correlations between all tokens(especially as image size or spectral bands increase)and limited ability to model local boundary information due to lacking explicit enhancement mechanisms.This paper proposes a novel method,bridge transformer network fused with deep graph convolution(BTDGC),to address these issues.The framework includes three components as follows:a double random masking mechanism(DRMM)that forces the model to infer masked features from context during training,a bridge transformer(BT)module with bridge tokens for cross-region feature interaction and a Deep Graph Convolutional Pooling(DGCP)module that preserves spatial topology while aggregating hierarchical information.Experiments on standard hyperspectral datasets show BTDGC outperforms mainstream methods in classification accuracy and robustness,effectively balancing global modelling and local boundary representation.The code is available at http://gffzz188fe103f8f1460asnvfxbkvkp9cc609o.ffgz.tsg.suse.edu.cn/jenny3489/BTDGC.
摘要Dear Editor,This letter presents a novel graph neural network, namely modularized graph convolution network(MGCN), to address the underexplored issue in graph convolution networks(GCNs), wherein the weights for neighbor aggregation are fixed, leading to the limited capability of capturing diverse relationships among nodes for representation learning. Conventional GCNs always learn node representations in the graph according to the weights computed from the graph Laplacian, consequently overlooking the similarity and group cohesiveness of node features.
基金supported by the National Key Research and Development Program(No.2022YFC2807400)the National Natural Science Foundation of China(Nos.12265003 and 12205044)。
摘要Aerial surveys are dynamic and continuous processes,and there are different height distributions of the ground in the measurement area,which leads to problems such as overlapping measurement areas and inaccurate altitude correction during the survey process.Commonly used terrain correction methods are based on the concept of finite elementization of ground surface radioactive sources,using GPS coordinates,radar altitude,and ground elevation distribution information from aerial surveys,combined with the sourceless efficiency calibration method to construct a response matrix,which is then inverted for surface nuclide content.However,most of the sourceless efficiency calibration methods used are numerical calculations that consider the body detector as a point detector and do not consider the changes in intrinsic detection efficiency under different incident directions of gamma rays.Therefore,when the altitude of the measurement area varies significantly or the flight altitude of the aerial survey is relatively low,such sourceless efficiency calibration method calculations tend to have a large bias,which affects the accuracy of the terrain correction.To address the above problems,this study employs a novel sourceless efficiency calibration method based on the Boolean operation of the ray deposition process and simplifies the traditional body source measurement model to a surface source measurement model to achieve fast and accurate efficiency calibration.Then,through the discretization of the measurement process,the static measurement process is superposed as equivalent to the dynamic measurement process,and the dynamic measurement response matrix is built and optimized based on the calibration method.Finally,the PSO-MLEM algorithm was used to solve the dynamic measurement response matrix to achieve dynamic terrain correction of aerial survey data.Analysis of the Baiyun'ebo test area revealed that,after applying dynamic terrain correction,the inverted anomalies in uranium(eU),thorium(eTh),and potassium(K)concentrations were closer to ground measurements(within 5.72%-30.79%)and exhibited clearer anomaly boundaries compared to traditional height-based corrections.However,owing to the inherent statistical fluctuations and characteristics of matrix inversion,higher measurement values tend to absorb lower ones,potentially enlarging the anomalous regions.Nevertheless,the highanomaly regions after inversion largely coincided with the ground truth validation,demonstrating that the proposed method can effectively correct airborne gamma spectrometry data.
基金The National Natural Science Foundation of China under contract No.42376174the Natural Science Foundation of Shanghai under contract No.23ZR1426900。
摘要This study explores the three-dimensional(3-D)characteristics of oceanic eddies in the Southern Ocean from 2021 to 2023.Copernicus Marine Environment Monitoring Service(CMEMS)GLORYS12V1 product,which provides daily current field data at a(1/12)°grid resolution,is used to identify eddies with radii>10 km.Additionally,the daily sea level anomaly product from Haiyang-2(HY-2)altimeters is used to detect mesoscale eddies with radii>40 km.GLORYS12V1 detects over ten times more surface eddies than HY-2,likely due to its higher spatial and temporal resolution,which allows better identification of smaller-scale features.Both eddy radius and eddy kinetic energy(EKE)differences between layers decrease with depth.At 0.5 m,EKE is lower than at 300–600 m,where it stabilizes.Over 90%of eddies at these depths show center deflection angles under 3°,defined as the angular offset between eddy centers in adjacent layers relative to the vertical(0°)axis.In a 3-D eddy,the center may shift with depth due to physical processes,causing non-zero center deflection angles between layers.Below 300 m,eddy radius differences are more frequently under 20 km than in the upper 0.5–300 m,where baroclinic instability amplifies,and barotropic instability suppresses cross-layer variability.The influence of both instabilities weakens with depth.In the upper ocean(0.5–300 m),baroclinic instability increases the angular offsets between eddy centers.In contrast,barotropic instability reduces these offsets.At 300–600 m,both promote better vertical alignment,indicating greater structural stability.Overall,this study enhances the understanding of the vertical structure and dynamics of oceanic eddies in the Southern Ocean.
基金supported by the National Natural Science Foundation of China(Nos.12405194 and 52276052)the National Key R&D Program of China(Nos.2024YFE03230200 and 2022YFE03160002)the Natural Science Foundation of Chongqing,China(No.CSTB2025NSCQ-GPX0761)。
摘要To accelerate the development and utilization of fusion energy,the China Fusion Engineering Test Reactor(CFETR)has been proposed as a bridge between the International Thermonuclear Experimental Reactor and demonstration fusion reactors.The primary objective of the CFETR is to achieve fusion energy transformation and tritium self-sufficiency,which is realized through the function of the blanket.In this study,a neutronicshermal-hydraulics/mechanics coupling method is developed and applied to a helium-cooled ceramic breeder(HCCB)blanket,which is one of the two blanket candidates for the CFETR.A three-dimensional full-scale model is utilized in the coupling analysis to obtain the distributions of the neutronic,thermal-hydraulic,and mechanical parameters.A structural assessment of the CFETR HCCB blanket is then conducted considering steady-state conditions and two transient scenarios.The results demonstrate that following optimization of the blanket structure,the maximum temperatures of the different components remain below the safety limit of the corresponding materials.The structural assessment indicates that the blanket maintains its structural integrity under steady-state conditions.However,immediately after an in-box loss-of-coolant accident,structural failure owing to stress concentration may occur.Additionally,in the early stage of a loss-of-flow accident,the stress at the joint point between the cooling plate and cap exceeds the allowable stress of the material,potentially leading to structural failure within 17 s if no protective response is implemented.These findings provide comprehensive insights into the performance and safety of the CFETR HCCB blanket design.
基金funding support from the Science and Technology Innovation Program of Xiongan New Area(Grant No.2024XAGG0016)the National Key R&D Program of China(Grant No.2024YFE0198500)the National Natural Science Foundation of China(Grant No.U2469207).
摘要The creation of a three-dimensional(3D)geological model plays a crucial guiding role in engineering.However,in practice,due to the sparsity of boreholes and the invisibility of strata,accurately reconstructing a 3D geological model has always been a challenging task.In this study,a data-and knowledge-driven 3D geological reconstruction method is proposed,where the Inverse Distance Weighting(IDW)method is integrated with computer vision techniques to improve the accuracy and reliability of geological modeling.The reconstruction of the geological model is realized by the reconstruction of continuous cross-sections in one direction.The reconstruction method integrates two deep learning models:a repair model that learns stratigraphic relationships from borehole data to reconstruct cross-sections,and an interpolation model that predicts intermediate sections by capturing stratigraphic distribution and variation patterns.The comparison with the IDW method and the ordinary kriging method on the virtual data verifies that the proposed method can capture the spatial distribution characteristics of the strata.An engineering example proves that the proposed method can be successfully applied to complex stratum modeling.The proposed method enhances and facilitates intuitive observation of both the reconstructed results and their uncertainties.The proposed method can provide guidance for underground engineering construction sites and contribute to their digital transformation.
基金supported by the National Natural Science Foundation of China(Grant Nos.42272338 and 41902275)China Railway Tunnel Group Co.,Ltd.(Grant No.CZ02-08)+4 种基金Sichuan Transportation Science and Technology Program(Grant No.2018-ZL-02)Department of Transportation of Zhejiang Province(Grant No.202213)China Railway First Survey and Design Institute Group Co.,Ltd.(Grant No.2022KY53ZD(CYH)-10)Chongqing Institute of Geology and Mineral Resources(Grant No.TICG-K2024001)Special Project for Performance Incentive and Guidance of Scientific Research Institutions in Chongqing(Grant No.CSTB2023JXJL-YFX0006).
摘要The numerical manifold method,extensively utilized in numerical computations,faces significant challenges in generating complex manifold elements,particularly for three-dimensional applications.To overcome this challenge,the meshfree numerical manifold method is developed by integrating the moving least-squares method into the numerical manifold method,effectively bypassing the need for meshing complex geometric objects.However,the implementation of the moving least-squares method introduces computational efficiency issues.To mitigate these,parallel computing methods have been incorporated,resulting in a tenfold increase in the speed of assembling the stiffness matrix with central processing unit parallelism,and a twentyfold increase with graphics processing unit parallelism.The static mechanical system equations for the meshfree numerical manifold method are derived using the Galerkin method.The method’s effectiveness and accuracy are then validated through a series of numerical experiments.The experiments demonstrated that the meshfree numerical manifold method achieves a high precision with minimal nodes and integration points.Additionally,positioning nodes outside the domain significantly improves computational accuracy at the boundaries.
基金supported by the National Natural Science Foundation of China(62402399)the New Chongqing Youth Innovation Talent Project(CSTB2024NSCQ-QCXMX0035)。
摘要Dear Editor,D2This letter presents a node feature similarity preserving graph convolutional framework P G.Graph neural networks(GNNs)have garnered significant attention for their efficacy in learning graph representations across diverse real-world applications.
基金supported,in part,by the National Nature Science Foundation of China under Grant 62272236,62376128in part,by the Natural Science Foundation of Jiangsu Province under Grant BK20201136,BK20191401.
摘要Video emotion recognition is widely used due to its alignment with the temporal characteristics of human emotional expression,but existingmodels have significant shortcomings.On the one hand,Transformermultihead self-attention modeling of global temporal dependency has problems of high computational overhead and feature similarity.On the other hand,fixed-size convolution kernels are often used,which have weak perception ability for emotional regions of different scales.Therefore,this paper proposes a video emotion recognition model that combines multi-scale region-aware convolution with temporal interactive sampling.In terms of space,multi-branch large-kernel stripe convolution is used to perceive emotional region features at different scales,and attention weights are generated for each scale feature.In terms of time,multi-layer odd-even down-sampling is performed on the time series,and oddeven sub-sequence interaction is performed to solve the problem of feature similarity,while reducing computational costs due to the linear relationship between sampling and convolution overhead.This paper was tested on CMU-MOSI,CMU-MOSEI,and Hume Reaction.The Acc-2 reached 83.4%,85.2%,and 81.2%,respectively.The experimental results show that the model can significantly improve the accuracy of emotion recognition.
基金Supported by the Major Science and Technology Project of Petro China(2023ZZ16YJ01)Key Scientific and Technology Project of Petro China Southwest Oil&Gas Field Company(JS2022-181)。
摘要Considering the complexities of gas-water relationships in the gas reservoirs,unclear natural gas distribution and difficult exploration expansion of the Sinian–Permian natural gas in the Penglai gas area of the central Sichuan Basin,this study investigates the gas source,charging processes and enrichment patterns of gas reservoirs based on reservoir characterization,natural gas geochemical analysis,reservoir testing,well logging-seismic data interpretation,as well as basin modeling and dynamic analysis.The results are obtained in three aspects.First,four sets of highly efficient source rocks are developed beneath the salt of the Triassic Jialingjiang Formation,dominated by the Cambrian source rocks.The reservoirs exhibit strong heterogeneity,with six sets of effective reservoirs being isolated from each other yet dynamically connected.Multi-stage strike-slip fault-related fault-fracture-cavity-unconformity systems constitute the hydrocarbon migration network.Second,overpressure generated by hydrocarbon generation in the Cambrian source rocks drove bidirectional hydrocarbon expulsion from the source kitchen.Multiple sources,including cracked gas from paleo-oil reservoirs and residual hydrocarbons within source rocks,contributed to the hydrocarbon supply.The Sinian–Permian system underwent multiple dynamic hydrocarbon accumulation processes,resulting in the formation of extensive“sweet spots”within multi-layered heterogeneous reservoirs,which were subsequently modified by late-stage gas adjustments to their current form.Third,a three-dimensional accumulation model for deep marine natural gas is established,with multi-source hydrocarbon supply,three-dimensional migration,multi-stage accumulation,dynamic adjustment and lithology-controlled distribution.Large-scale reservoirs within positive structural settings,late-stage structurally stable areas,and slope structures are identified as favorable plays for gas exploration.
基金funded by National Social Science Fund of China,grant number 23BYY197.
摘要Image captioning,a pivotal research area at the intersection of image understanding,artificial intelligence,and linguistics,aims to generate natural language descriptions for images.This paper proposes an efficient image captioning model named Mob-IMWTC,which integrates improved wavelet convolution(IMWTC)with an enhanced MobileNet V3 architecture.The enhanced MobileNet V3 integrates a transformer encoder as its encoding module and a transformer decoder as its decoding module.This innovative neural network significantly reduces the memory space required and model training time,while maintaining a high level of accuracy in generating image descriptions.IMWTC facilitates large receptive fields without significantly increasing the number of parameters or computational overhead.The improvedMobileNet V3 model has its classifier removed,and simultaneously,it employs IMWTC layers to replace the original convolutional layers.This makes Mob-IMWTC exceptionally well-suited for deployment on lowresource devices.Experimental results,based on objective evaluation metrics such as BLEU,ROUGE,CIDEr,METEOR,and SPICE,demonstrate that Mob-IMWTC outperforms state-of-the-art models,including three CNN architectures(CNN-LSTM,CNN-Att-LSTM,CNN-Tran),two mainstream methods(LCM-Captioner,ClipCap),and our previous work(Mob-Tran).Subjective evaluations further validate the model’s superiority in terms of grammaticality,adequacy,logic,readability,and humanness.Mob-IMWTC offers a lightweight yet effective solution for image captioning,making it suitable for deployment on resource-constrained devices.
摘要Accurate modeling of ship magnetic fields is important for predicting their spatial distribution to improve the magnetic stealth effect of ships.This study proposes an extrapolation model for ship magnetic fields based on genetic algorithms and convolutional neural networks(CNNs).The magnetic probe position matrix of the traditional equivalent source is utilized as input,and the three-directional components of the magnetic field measured by the probes are employed as output.The extrapolation model for ship magnetic fields is obtained through iterative training and fitting with CNNs.Variables such as the number of magnetic dipoles,the distance between magnetic dipoles,the size and quantity of convolutional kernels,batch size,learning rate,and L2 regularization coefficient are optimized to boost the accuracy of the extrapolation model for magnetic fields.The fitting accuracy of the extrapolation model for ship magnetic fields is used as the optimization objective.Based on a finite element simulation model of ship magnetic fields,the accuracy and robustness of the CNN algorithm under different magnetic field conditions are validated using the known standard depth plane,the unknown depth at 1.125 times the standard depth plane,and the unknown depth at 1.25 times the standard depth plane.Results show that,after optimization,the fitting error for the magnetic field extrapolation model based on CNN is 1.50%for the standard depth plane,1.63%for the unknown depth at 1.125 times the standard depth plane,and 2.36%for the unknown depth at 1.25 times the standard depth plane.The error remains below 5%under varying magnetic field conditions.When a random measurement error of 0%-5%is introduced for the magnetic probes,the prediction error at 1.25 times the standard depth plane is 2.30%;with a random error of 0%-10%,the prediction error is 4.95%.This approach significantly improves the accuracy and robustness of magnetic field extrapolation,which makes it an effective and feasible method for ship magnetic field modeling.
基金supported in part by the National Nature Science Foundation of China under Grants 62476216 and 62006184in part by the Key Research and Development Program of Shaanxi Province under Grant 2024GX-YBXM-146+1 种基金in part by the Scientific Research ProgramFunded by EducationDepartment of the Shaanxi Provincial Government under Grant 23JP091the Youth Innovation Team of Shaanxi Universities.
摘要Traffic flow prediction is of great importance in traffic planning,road resource management,and congestion mitigation.However,existing prediction have significant limitations in modeling multi-scale spatial-temporal features,particularly in capturing temporal periodicity and spatial dependency in dynamically evolving traffic networks.This paper proposes a novel framework of traffic flow prediction,referred to as Adaptive Graph Fusion Dual-scale Convolutional Network(AGFDCN),which integrates spatial-temporal dynamic graphs with dual-scale convolutional networks.Specifically,we introduce a Dual-Scale Temporal Network,which combines long-and short-term dilated causal convolutions with a temporal decay-aware attention mechanism to efficiently capture traffic patterns across multiple temporal scales.Furthermore,we design a Dynamic Adaptive Graph Module,which models complex spatial dependencies in traffic networks through an adaptive graph fusion mechanism and a dual-path attention-gated module.Finally,the temporal and spatial representations are integrated by employing a gated fusion mechanism,enhancing the overall prediction performance.Experimental results obtained based on three highway datasets(i.e.,PEMS04,PEMS07 and PEMS08)verify that the proposed model outperforms several state-of-the-art baselines in various evaluation metrics.Compared to the spatial-temporal graph model AGCRN with best performance in the baseline models,the proposed model exhibits significant improvements across all datasets:it achieves reduces of MAE by 42.07%and RMSE by 35.43%on PEMS04;MAE by 28.35%and RMSE by 29.28%on PEMS07;and MAE by 30.52%and RMSE by 30.73%on PEMS08,respectively,validating its effectiveness in modeling complex spatial-temporal traffic data and its robustness in handling sudden traffic changes.
基金Supported by the National Key Research and Development Program of China(No.2023YFC3008202)the National Natural Science Foundation of China(No.42406019)the Scientific Research Fund of Zhejiang Provincial Education Department(No.Y202353066)。
摘要The prediction of sea surface partial pressure of carbon dioxide(pCO2)in the South China Sea is crucial for understanding the region’s contribution to the global carbon budget and its interactions with climate change.We applied the Spatiotemporal Convolutional Long Short-Term Memory(STConvLSTM)model,integrating key environmental factors including sea surface temperature(SST),sea surface salinity(SSS),and chlorophyll a(Chl a),to predict and analyze sea surface pCO2in the South China Sea.The model demonstrated high accuracy in short-term predictions(1 month),with a mean absolute error(MAE)of 0.394,a root mean square error(RMSE)of 0.659,and a coefficient of determination(R2)of 0.998.For long-term predictions(12 months),the model maintained its predictive capability,with an MAE of 0.667,RMSE of 1.255,and R2of 0.994.Feature importance analysis revealed that sea surface pCO2and SST were the main drivers of the model’s predictions,whereas Chl a and SSS had relatively minor impacts.The model’s generalization ability was further validated in the northwest Pacific Ocean and tropical Pacific Ocean,where it successfully captured the spatiotemporal variation in pCO2with small prediction errors.The ST-ConvLSTM model provides an efficient and accurate tool for forecasting and analyzing sea surface pCO2in the South China Sea,offering new insights into global carbon cycling and climate change.This study demonstrates the potential of deep learning in marine science and provides a significant technical support for global changes and marine ecosystem research.
基金supported in part by Beijing Natural Science Foundation under Grant L251058in part by Project of State Key Lab of Intelligent Transportation System under Grant 2024-A001.
摘要Traffic holographic perception refers to the real-time,high-fidelity,and multi-dimensional sensing of traffic states through the fusion of heterogeneous sensors,including cameras,radars,and connected vehicle data.The multi-source perception data obtained thereby can provide a complete digital representation of the road network for the Intelligent Transportation System(ITS).However,sensors are vulnerable to environmental interference,which can result in data loss at specific points or along arterial highways for certain periods,potentially undermining system safety and decision-making reliability.To address these challenges,a deep learning method based on Graph Convolutional Networks(GCN)and Gated Recurrent Units(GRU)is proposed,leveraging Artificial Intelligence(AI)and intelligent connected technologies for real-time acquisition of multi-sensor perception data.A feature-level fusion integrates multi-source perception data.GCN captures spatial dependencies from the road network topology,while GRU extracts temporal features from time series,enabling accurate imputation of missing traffic data.The method is evaluated at intelligent connected intersections in the Beijing High-level Autonomous Driving Demonstration Area.Results show that the accuracy of long-term traffic state completion reaches 89.36%,and the Root Mean Square Error(RMSE)is reduced by 17.2%compared to the Long Short-Term Memory(LSTM)baseline.This framework provides a practical solution for deploying traffic holographic perception technology in secure and trustworthy ITS.
基金financial support from the National Natural Science Foundation of China(Grant No.52209125).
摘要The time-dependent failure of surrounding rock in deep engineering is essentially controlled by the evolution of microcracks,with the pre-existing fracturing state induced by excavation playing a crucial role in the subsequent time-dependent fracturing process.From the perspective of microcrack development,it is a continuous,dynamic process.Therefore,taking the microcrack propagation process as the fundamental principle,this paper proposes a novel three-dimensional(3D)time-dependent model for hard rock that can depict the entire fracturing process within a unified theoretical framework.This developed model discards the traditional tri-modal partition method based on deformation,and instead adopts an analysis approach centred on time-dependent tensile and shear fracturing.The results show that the time-dependent deformation of hard rock is the macroscopic manifestation of the progressive evolution of microcracks over time.Under true triaxial stress,the growth tendency of cracks in hard rock is orientation-dependent throughout the entire loading process.This developed model provides a mechanical explanation for key time-dependent fracture characteristics observed in true triaxial creep tests,including the anisotropy of time-dependent deformation and the preferred orientation of macroscopic failure plane,and provides a novel framework for elucidating the time-dependent failure process of hard rock.
基金supported by the National Natural Science Foundation of China(Grant No.12372373,12072363)the National Key Research and Development Program of China(Grant No.2020YFA0711800)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX25_2953).
摘要Methane in situ multistage explosive fracturing(MISMEF)presents a promising technique for enhancing complex fracture networks in deep,low-permeability shale reservoirs.This study employed highfidelity3D simulations,integrating a characteristic methane–oxygen explosion load model with dynamic relaxation and full-restart methods,to elucidate the coupled interactions between explosive loading and in situ stress.A damage-based zoning approach was developed to quantify fracture characteristics,leading to the proposal of a novel dimensionless evaluation index,Fmef.Results showed that in situ stress predominantly suppressed longitudinal fracture growth,while multistage loading effectively enhanced both lateral and longitudinal propagation following a"delayed initiation–accelerated propagation"pattern.Fracture volume exhibited nonlinear amplificationwith increasing stages,and the continuous increase in fractal dimension suggested improved network connectivity.Energy redistribution driven by the coupled effects of in situ stress and staged loading promoted complex network formation near the wellbore,with MISMEF progressively reducing fracture thresholds through rock mass weakening.Fmef analysis confirmedsignificantimprovement in fracture network quality across all stress conditions,particularly under medium to high in situ stress.This work provides critical mechanistic insights and a theoretical foundation for optimizing MISMEF in deep shale reservoir stimulation.
基金supported by the Ministry of Education(MOE)Singapore,Academic Research Fund(AcRF)Tier 1(RG65/22)。
摘要Convolutional neural networks(CNNs)have shown remarkable success across numerous tasks such as image classification,yet the theoretical understanding of their convergence remains underdeveloped compared to their empirical achievements.In this paper,the first filter learning framework with convergence-guaranteed learning laws for end-to-end learning of deep CNNs is proposed.Novel update laws with convergence analysis are formulated based on the mathematical representation of each layer in convolutional neural networks.The proposed learning laws enable concurrent updates of weights across all layers of the deep convolutional neural network and the analysis shows that the training errors converge to certain bounds which are dependent on the approximation errors.Case studies are conducted on benchmark datasets and the results show that the proposed concurrent filter learning framework guarantees the convergence and offers more consistent and reliable results during training with a trade-off in performance compared to stochastic gradient descent methods.This framework represents a significant step towards enhancing the reliability and effectiveness of deep convolutional neural network by developing a theoretical analysis which allows practical implementation of the learning laws with automatic tuning of the learning rate to guarantee the convergence during training.
摘要BACKGROUND Laparoscopic sleeve gastrectomy(LSG)is currently the most commonly performed bariatric surgery owing to its effective weight loss and low complication rates.Nonetheless,some patients experience weight regain or insufficient weight loss due to residual gastric dilation,the factors of which remain unclear.AIM To evaluate changes in residual gastric volume after LSG using three-dimensional computed tomography reconstruction and to investigate the factors contributing to gastric dilation.METHODS This retrospective study included 50 patients who underwent LSG.Preoperative clinical and laboratory data were obtained.The residual gastric volume was measured using three-dimensional computed tomography reconstruction at 1 month and 3 months postoperatively.The total sleeve volume,tube volume,antral volume,and tube-to-antral volume ratio were also assessed.Resected gastric volume and staple line length were measured during surgery.Weight metrics and laboratory indices were recorded at 1 month,3 months,6 months,and 12 months postoperatively.The Eating Behavior After Bariatric Surgery Questionnaire and Gastroesophageal Reflux Disease Questionnaire(GERD-Q)were used to assess the dietary behavior of patients after LSG.Correlation between the degree of residual gastric dilation and percent total weight loss(%TWL)at 12 months postoperatively was analyzed.Univariate and multivariate correlation analyses were conducted to identify risk factors for residual gastric dilation after LSG.RESULTS The 50 included patients had a mean preoperative body mass index of 42.27±7.19 kg/m2 and average%TWL of 34%±7%at 1 year after LSG.At 1 month after LSG,the mean tube volume,antral volume,and total sleeve volume were 45.93±16.75 mL,115.85±44.92 mL,and 161.77±55.37 mL,respectively.At 3 months after LSG,the residual gastric volume showed statistically significant dilation(average dilation degree:13.50%±17.35%).%TWL at 1 year significantly correlated with residual gastric dilation(P<0.05).Univariate and multivariate linear regression analyses revealed that preoperative type 2 diabetes,residual gastric volume at 1 month after LSG,and GERD-Q scores were independent risk factors influencing the degree of residual gastric dilation.CONCLUSION In conclusion,residual gastric dilation after LSG significantly affected the efficacy of weight loss.Preoperative type 2 diabetes,residual gastric volume at 1 month after LSG,and GERD-Q scores were independent risk factors affecting the degree of residual gastric dilation.