As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security ...As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.展开更多
An adaptive human tracking method across spatially separated surveillance cameras with non-overlapping fields of views （FOVs） is proposed. The method relies on the two cues of the human appearance model and spatio-t...An adaptive human tracking method across spatially separated surveillance cameras with non-overlapping fields of views （FOVs） is proposed. The method relies on the two cues of the human appearance model and spatio-temporal information between cameras. For the human appearance model, an HSV color histogram is extracted from different human body parts （head, torso, and legs）, then a weighted algorithm is used to compute the similarity distance of two people. Finally, a similarity sorting algorithm with two thresholds is exploited to find the correspondence. The spatio- temporal information is established in the learning phase and is updated incrementally according to the latest correspondence. The experimental results prove that the proposed human tracking method is effective without requiring camera calibration and it becomes more accurate over time as new observations are accumulated.展开更多
An adaptive topology learning approach is proposed to learn the topology of a practical camera network in an unsupervised way. The nodes are modeled by the Gaussian mixture model. The connectivity between nodes is jud...An adaptive topology learning approach is proposed to learn the topology of a practical camera network in an unsupervised way. The nodes are modeled by the Gaussian mixture model. The connectivity between nodes is judged by their cross-correlation function, which is also used to calculate their transition time distribution. The mutual information of the connected node pair is employed for transition probability calculation. A false link eliminating approach is proposed, along with a topology updating strategy to improve the learned topology. A real monitoring system with five disjoint cameras is built for experiments. Comparative results with traditional methods show that the proposed method is more accurate in topology learning and is more robust to environmental changes.展开更多
New approaches for facility distribution in chemical plants are proposed including an improved non-overlapping constraint based on projection relationships of facilities and a novel toxic gas dispersion constraint. In...New approaches for facility distribution in chemical plants are proposed including an improved non-overlapping constraint based on projection relationships of facilities and a novel toxic gas dispersion constraint. In consideration of the large number of variables in the plant layout model, our new method can significantly reduce the number of variables with their own projection relationships. Also, as toxic gas dispersion is a usual incident in a chemical plant, a simple approach to describe the gas leakage is proposed, which can clearly represent the constraints of potential emission source and sitting facilities. For solving the plant layout model, an improved genetic algorithm (GA) based on infeasible solution fix technique is proposed, which improves the globe search ability of GA. The case study and experiment show that a better layout plan can be obtained with our method, and the safety factors such as gas dispersion and minimum distances can be well handled in the solution.展开更多
Mechanical behaviors of granular materials are complicated and greatly influenced by the particle shape.Current,some composite approaches have been proposed for realistic particle shape modelling within discrete eleme...Mechanical behaviors of granular materials are complicated and greatly influenced by the particle shape.Current,some composite approaches have been proposed for realistic particle shape modelling within discrete element method(DEM),while they cannot give a good representation to the shape and mass properties of a real particle.In this work,a novel algorithm is developed to model an arbitrary particle using a cluster of non-overlapping disks.The algorithm mainly consists of two components:boundary filling and domain filling.In the boundary filling,some disks are placed along the boundary for a precise representation of the particle shape,and some more disks are placed in the domain to give an approximation to the mass properties of the particle in the domain filling.Besides,a simple method is proposed to correct the mass properties of a cluster after domain filling and reduce the number of the disks in a cluster for lower computational load.Moreover,it is another great merit of the algorithm that a cluster generated by the algorithm can be used to simulate the particle breakage because of no overlaps between the disks in a cluster.Finally,several examples are used to show the robust performance of the algorithm.A current FORTRAN version of the algorithm is available by contacting the author.展开更多
To track human across non-overlapping cameras in depression angles for applications such as multi-airplane visual human tracking and urban multi-camera surveillance,an adaptive human tracking method is proposed,focusi...To track human across non-overlapping cameras in depression angles for applications such as multi-airplane visual human tracking and urban multi-camera surveillance,an adaptive human tracking method is proposed,focusing on both feature representation and human tracking mechanism.Feature representation describes individual by using both improved local appearance descriptors and statistical geometric parameters.The improved feature descriptors can be extracted quickly and make the human feature more discriminative.Adaptive human tracking mechanism is based on feature representation and it arranges the human image blobs in field of view into matrix.Primary appearance models are created to include the maximum inter-camera appearance information captured from different visual angles.The persons appeared in camera are first filtered by statistical geometric parameters.Then the one among the filtered persons who has the maximum matching scale with the primary models is determined to be the target person.Subsequently,the image blobs of the target person are used to update and generate new primary appearance models for the next camera,thus being robust to visual angle changes.Experimental results prove the excellence of the feature representation and show the good generalization capability of tracking mechanism as well as its robustness to condition variables.展开更多
A boundary element method based on non-overlapping domain decomposition method to solve the time-dependent diffusion equations is presented. The time-dependent fundamental solution is used in the formulation of bounda...A boundary element method based on non-overlapping domain decomposition method to solve the time-dependent diffusion equations is presented. The time-dependent fundamental solution is used in the formulation of boundary integrals and the time integration process always restarts from the initial time condition. The process of replacing the interface values, which needs a summation of boundary integrals related to the boundary values at previous time steps can be treated in parallel iterative procedure. Numerical experiments demonstrate that the implementation of the present algorithm is efficient.展开更多
NIST(National Institute of Standards and Technology) statistical test recognized as the most authoritative is widely used in verifying the randomness of binary sequences. The Non-overlapping Template Matching Test as ...NIST(National Institute of Standards and Technology) statistical test recognized as the most authoritative is widely used in verifying the randomness of binary sequences. The Non-overlapping Template Matching Test as the 7 th test of the NIST Test Suit is remarkably time consuming and the slow performance is one of the major hurdles in the testing process. In this paper, we present an efficient bit-parallel matching algorithm and segmented scan-based strategy for execution on Graphics Processing Unit(GPU) using NVIDIA Compute Unified Device Architecture(CUDA). Experimental results show the significant performance improvement of the parallelized Non-overlapping Template Matching Test, the running speed is 483 times faster than the original NIST implementation without attenuating the test result accuracy.展开更多
BACKGROUND Elderly patients undergoing laparoscopic colorectal cancer surgery are at high risk for hypothermia-related complications.This study explores the efficacy of periop-erative composite insulation intervention...BACKGROUND Elderly patients undergoing laparoscopic colorectal cancer surgery are at high risk for hypothermia-related complications.This study explores the efficacy of periop-erative composite insulation interventions in maintaining normothermia and reducing postoperative risks in this vulnerable group.AIM To evaluate the efficacy of perioperative composite insulation in older patients undergoing colorectal cancer surgery.METHODS We selected 100 older patients who underwent laparoscopic surgery for colorectal cancer at Huzhou Central Hospital from September 2023 to April 2024.Using a random number table,patients were divided into a control group and inter-vention group of 50 patients each.After returning to the regular ward,the con-ventional group received traditional insulation intervention measures,while the intervention group received composite insulation nursing intervention.We ob-served and recorded postoperative blood pressure and heart rate changes,as well as postoperative anesthesia recovery time and incidence of complications.RESULTS The statistical results showed significant differences(P<0.05)in heart rate changes and systolic blood pressure between the two groups.There was a sig-nificant change in heart rate between the groups immediately after surgery and at 15 and 30 minutes after surgery(P<0.05).The heart rate and systolic blood pressure of the intervention group were significantly lower than those of the control group at 15 and 30 minutes after surgery(P<0.05).The rewarming time of the intervention group was shorter than that of the control group,and the overall incidence of postoperative complications was significantly lower than that of the control group(P<0.05).CONCLUSION For elderly patients undergoing laparoscopic colorectal cancer surgery,a composite insulation intervention during the perioperative period can maintain body temperature,reduce postoperative stress,and significantly reduce the incidence of hypothermia and related complications.展开更多
ADER-WAF methods were first introduced by researchers E.F. Toro and V.A. Titarev. The linear stability criterion for the model equation for the ADER-WAF schemes is CCFL≤1, where CCFLdenotes the Courant-Friedrichs-Lew...ADER-WAF methods were first introduced by researchers E.F. Toro and V.A. Titarev. The linear stability criterion for the model equation for the ADER-WAF schemes is CCFL≤1, where CCFLdenotes the Courant-Friedrichs-Lewy (CFL) coefficient. Toro and Titarev employed CCFL=0.95for their experiments. Nonetheless, we noted that the experiments conducted in this study with CCFL=0.95produced solutions exhibiting spurious oscillations, particularly in the high-order ADER-WAF schemes. The homogeneous one-dimensional (1D) non-linear Shallow Water Equations (SWEs) are the subject of these experiments, specifically the solution of the Riemann Problem (RP) associated with the SWEs. The investigation was conducted on four test problems to evaluate the ADER-WAF schemes of second, third, fourth, and fifth order of accuracy. Each test problem constitutes a RP characterized by different wave patterns in its solution. This research has two primary objectives. We begin by illustrating the procedure for implementing the ADER-WAF schemes for the SWEs, providing the required relations. Afterward, following comprehensive testing, we present the range for the CFL coefficient for each test that yields solutions with diminished or eliminated spurious oscillations.展开更多
In this paper,we develop a fourth-order conservative wavelet-based shock-capturing scheme.The scheme is constructed by combining a wavelet collocation upwind method with the monotonic tangent of hyperbola for interfac...In this paper,we develop a fourth-order conservative wavelet-based shock-capturing scheme.The scheme is constructed by combining a wavelet collocation upwind method with the monotonic tangent of hyperbola for interface capturing(THINC)technique.We employ boundary variation diminishing(BVD)reconstruction to enhance the scheme’s effectiveness in handling shocks.First,we prove that wavelet collocation upwind schemes based on interpolating wavelets can be reformulated into a conservative form within the framework of wavelet theory,forming the foundation of the proposed scheme.The new fourthorder accurate scheme possesses significantly better spectral resolution than the fifth-and even seventh-order WENO-Z(weighted essentially non-oscillatory)schemes over the entire wave-number range.Moreover,the inherent low-pass filtering property of the wavelet bases allows them to filter high-frequency numerical oscillations,endowing the wavelet upwind scheme with robustness and accuracy in solving problems under extreme conditions.Notably,due to the wavelet multiresolution approximation,the proposed scheme possesses a distinctive shape-preserving property absent in the WENO-Z schemes and the fifth-order schemes with BVD reconstruction based on polynomials.Furthermore,compared to the fifth-order scheme with BVD reconstruction based on polynomials—which is significantly superior to the WENO schemes—the proposed scheme further enhances the ability to capture discontinuities.展开更多
This study investigates the capabilities of a non-hydrostatic global,variable-resolution model in simulating tropical cyclone precipitation,with historically significant Typhoon Fitow(1323)as a case study.Employing th...This study investigates the capabilities of a non-hydrostatic global,variable-resolution model in simulating tropical cyclone precipitation,with historically significant Typhoon Fitow(1323)as a case study.Employing three grid settings(24 km,60−10 km,60−3 km)and two microphysical parameterization schemes(WSM6 and Thompson),the study investigates the influence of grid resolution and microphysical parameterization on precipitation simulation.The simulated precipitation intensity and spatial distribution of high-resolution grids exhibit better agreement with the observations compared to the coarse-resolution grids.Specifically,the 60−3 km grid setting shows the greatest improvement in spatial correlation with observed precipitation data compared to the 24 km grid.Through the analysis of the thermal dynamic field,the high-resolution grid configuration more effectively simulates indicators for strong convective weather events,such as convective available potential energy(CAPE),helicity,and nonadiabatic heating.Analysis of TRMM satellite observations reveals that the high-resolution grid simulation results more accurately capture the distribution characteristics of hydrometeor mixing ratio compared to the coarse-resolution grids.Differences in hydrometeor content within convective clouds are more pronounced across grid resolutions than in stratiform clouds,even with the same parameterization scheme.Additionally,at the same resolution,the disparity in ice-phase particle content between the two schemes is much greater than the disparity in liquid-phase particle content.It is also noteworthy that the WSM6 scheme delivers superior performance compared to the Thompson scheme.In summary,this study demonstrates that refining model resolution has a more significant impact on precipitation intensity than the selection of physical parameterization scheme.The Model for Prediction Across Scales(MPAS),using a high-resolution variable-resolution grid,can be effectively used for typhoon precipitation simulation research.展开更多
Numerical models play an important role in convective-scale forecasting,and dual-polarization radar observations can provide detailed microphysical data.In this study,we implement a direct assimilation operator for du...Numerical models play an important role in convective-scale forecasting,and dual-polarization radar observations can provide detailed microphysical data.In this study,we implement a direct assimilation operator for dual-polarization radar data using the hydrometeor background error covariance(HBEC)in the China Meteorological Administration MESO-scale weather forecasting system(CMA-MESO,formerly GRAPES-MESO)and conducted assimilation and forecasting experiments with X-band and S-band dual-polarization radar data on two cases.The results indicate that the direct assimilation of dual-polarization radar data enhanced the microphysical fields and the thermodynamic structure of convective systems to some extent based on the HBEC,thereby improving precipitation forecasts.Among the sensitivity tests of microphysical parameterization schemes,including the LIUMA scheme,the THOMPSON scheme,and the WSM6scheme(WRF Single-Moment 6-class),we find that the greatest improvement in the equivalent potential temperature,relative humidity,wind,and accumulated precipitation forecasts occurred in the experiment using the WSM6 scheme,as the distribution of solid precipitation particles was closer to the hydrometeor classification algorithm from the dualpolarization radar observations in our cases.展开更多
Reasonable greening design can effectively alleviate campus heat environment issues.This study uses the ENVI-met numerical model,along with in-situ observations and simulations,to analyze the thermal environment under...Reasonable greening design can effectively alleviate campus heat environment issues.This study uses the ENVI-met numerical model,along with in-situ observations and simulations,to analyze the thermal environment under three different greening schemes in typical areas of the Guangzhou University campus.The results indicate that the outdoor thermal environment is significantly influenced by the underlying surface materials and vegetation.The temperature of brick-paved surface is 0.9℃higher than that of natural soil surfaces under tree shade.Numerical simulations further confirm that increasing vegetation coverage effectively reduces outdoor air temperature.When the greening rate increases to 40%,the outdoor average temperature decreases by 0.7℃and relative humidity increases by approximately 4%,while wind speed remains minimal change.The cooling effect of vegetation is found to extend vertically to an altitude of 13 m.As the greening rate increases from 15%to 40%,the Mean Radiant Temperature(MRT)decreases from 50.6℃to 28.9℃,which is lower than the average ambient temperature,indicating improved thermal conditions.The Physiological Equivalent Temperature(PET)decreases from 40.2℃to 30.0℃,with the proportion of the areas classified as″very hot″reducing by 36.8%,significantly improving thermal comfort across most areas.Therefore,changing the ground material and greening landscape design can effectively alter the outdoor wind and thermal environment of the campus,thereby enhancing the thermal comfort for the campus community.展开更多
In this study,the Betts-Miller-Janjic(BMJ)convective adjustment scheme in the Weather Research and Forecasting(WRF)model version 4.0 was used to investigate the effect of itsα-parameter,which influences the first-gue...In this study,the Betts-Miller-Janjic(BMJ)convective adjustment scheme in the Weather Research and Forecasting(WRF)model version 4.0 was used to investigate the effect of itsα-parameter,which influences the first-guess potential temperature reference profile on the Madden-Julian oscillation(MJO)propagation and structure.This study diagnosed the MJO active phase composites of the MJO-filtered outgoing longwave radiation(OLR)during the December-to-February(DJF)period of 2006-2016 over the Indian Ocean(IO),Maritime Continent(MC),and western Pacific(WP).The results show that the MJO-filtered OLR intensity,propagation pattern,and MJO classification(standing,jumping,and propagating clusters)are sensitive to theα-value,but the phase speeds of propagating MJOs are not.Overall,with an increasingα-value,the simulated MJO-filtered OLR intensity increases,and the simulated propagation pattern is improved.Results also show that the intensity and propagation pattern of an eastward-propagating MJO are associated with MJO circulation structures and thermodynamic structures.Asαincreases,the front Walker cell and the low-level easterly anomaly are enhanced,which premoistens the lower troposphere and triggers more active shallow and congestus clouds.The enhanced shallow and congestus convection preconditions the lower to middle troposphere,accelerating the transition from congestus to deep convection,thereby facilitating eastward propagation of the MJO.Therefore,the simulated MJO tends to transfer from standing to eastward propagating asαincreases.In summary,increasing theα-value is a possible way to improve the simulation of the structure and propagation of the MJO.展开更多
Mesh reflector antennas are the mainstream of large space-borne antennas,and the stretching of the truss achieves their deployment.Currently,the truss is commonly designed to be a single degree of freedom(DOF)deployab...Mesh reflector antennas are the mainstream of large space-borne antennas,and the stretching of the truss achieves their deployment.Currently,the truss is commonly designed to be a single degree of freedom(DOF)deployable mechanism with synchronization constraints.However,each deployable unit’s drive distribution and resistance load are uneven,and the forced synchronization constraints lead to the flexible deformation of rods and difficulties in the deployment scheme design.This paper introduces an asynchronous deployment scheme with a multi-DOF closed-chain deployable truss.The DOF of the truss is calculated,and the kinematic and dynamic models are established,considering the truss’s and cable net’s real-time coupling.An integrated solving algorithm for implicit differential-algebraic equations is proposed to solve the dynamic models.A prototype of a six-unit antenna was fabricated,and the experiment was carried out.The dynamic performances in synchronous and asynchronous deployment schemes are analyzed,and the results show that the cable resistance and truss kinetic energy impact under the asynchronous deployment scheme are minor,and the antenna is more straightforward to deploy.The work provides a new asynchronous deployment scheme and a universal antenna modeling method for dynamic design and performance improvement.展开更多
The implementation of core competencies clarifies social talent needs and guides math classroom evaluation.Lower-grade primary students,highly malleable,need targeted teacher guidance.Teaching evaluation should meet t...The implementation of core competencies clarifies social talent needs and guides math classroom evaluation.Lower-grade primary students,highly malleable,need targeted teacher guidance.Teaching evaluation should meet the talent demands of the times,focusing on core literacy and essential character development.From this perspective,primary math teachers should optimize evaluation,build a diversified system,help students grow in math,find their learning position,and advance confidently.展开更多
Shale oil reservoir is generally characterized by well-developed bedding planes,and multi-cluster fracturing is the most effective technique to achieve stable shale oil production.In this paper,a multi-cluster fractur...Shale oil reservoir is generally characterized by well-developed bedding planes,and multi-cluster fracturing is the most effective technique to achieve stable shale oil production.In this paper,a multi-cluster fracturing model for a horizontal well in shale with high-density bedding planes is established.The fracture morphology,fracture geometry,fracturing area and multiple fracture propagation mechanism are analyzed under simultaneous fracturing,sequential fracturing,and alternative fracturing.Results show that in the case of small cluster spacing and three clusters,the growth of the middle fracture is inhibited and develops along the bedding planes under both simultaneous fracturing and alternative fracturing.For sequential fracturing,the increase in the interval time between each fracturing advances the post fracturing fracture deflecting to the pre-existing fractures through the bedding planes.The reactivation of the bedding planes can promote the extension of the fracturing area.Increasing the injection rate and the number of clusters promotes the activation of bedding planes.However,it is preferable to reduce the number of clusters to obtain more main fractures.Compared with modified alternating fracturing and cyclic alternating fracturing,alternating shut-in fracturing creates more main fractures towards the direction of the maximum in-situ stress.The fracturing efficiency for high-density layered shale is ranked as simultaneous fracturing>alternative fracturing>sequential fracturing.展开更多
The regenerative braking energy utilization system(RBEUS)stands as a promising technique for improving the efficiency and power quality of electrified railways.Beyond the vital aspects of energy management and control...The regenerative braking energy utilization system(RBEUS)stands as a promising technique for improving the efficiency and power quality of electrified railways.Beyond the vital aspects of energy management and control strategies,ensuring fault protection is paramount for the secure and steady operation of the traction power supply system(TPSS)integrated with RBEUS.This paper introduces an innovative protection scheme tailored to diverse RBEUS application scenarios.Firstly,fault categories are streamlined into three levels:system,equipment,and warning.Subsequently,a novel multi-port active power differential protection method,aligned with RBEUS operational principles,is crafted to serve as a comprehensive and sensitive main protection.Building upon this foundation,a hierarchical protection structure for RBEUS is established,addressing the intricacies and variations in fault types while boosting anti-disturbance capabilities under faulty conditions.Embracing the principle of railway-oriented safety,a collaborative RBEUS-TPSS protection scheme is put forth.Finally,through simulated scenarios encompassing various fault conditions,the proposed scheme’s feasibility and effectiveness are convincingly validated.展开更多
International carbon tax issues such as carbon leakage and carbon neutralization have become major topics of social concern.Based on the practical experience of carbon tax system in individual countries,this paper int...International carbon tax issues such as carbon leakage and carbon neutralization have become major topics of social concern.Based on the practical experience of carbon tax system in individual countries,this paper integrates the existing research of international carbon tax scholars to the classification and comparative analysis of international carbon tax schemes.Using a literature review approach,this dissertation mainly applies the method of qualitative analysis to explain and compare the contents of four international carbon tax options.Through the analysis and evaluation of individual countries’carbon tax practice,the two-country model is verified.Through the method of comparative analysis,the schemes are evaluated from four dimensions and an assessment is made.The difference of carbon tax among countries makes the internal policies of countries adjust accordingly with the changes of international environment,which promotes the gradual convergence of carbon tax schemes.The results intend to provide reference to further study the issue on international carbon tax.展开更多
基金supported by the Key Project of Joint Fund of the National Natural Science Foundation of China“Research on Key Technologies and Demonstration Applications for Trusted and Secure Data Circulation and Trading”(U24A20241)the National Natural Science Foundation of China“Research on Trusted Theories and Key Technologies of Data Security Trading Based on Blockchain”(62202118)+4 种基金the Major Scientific and Technological Special Project of Guizhou Province([2024]014)Scientific and Technological Research Projects from the Guizhou Education Department(Qian jiao ji[2023]003)the Hundred-Level Innovative Talent Project of the Guizhou Provincial Science and Technology Department(Qiankehe Platform Talent-GCC[2023]018)the Major Project of Guizhou Province“Research and Application of Key Technologies for Trusted Large Models Oriented to Public Big Data”(Qiankehe Major Project[2024]003)the Guizhou Province Computational Power Network Security Protection Science and Technology Innovation Talent Team(Qiankehe Talent CXTD[2025]029).
文摘As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.
基金The National Natural Science Foundation of China(No. 60972001 )the Science and Technology Plan of Suzhou City(No. SG201076)
文摘An adaptive human tracking method across spatially separated surveillance cameras with non-overlapping fields of views （FOVs） is proposed. The method relies on the two cues of the human appearance model and spatio-temporal information between cameras. For the human appearance model, an HSV color histogram is extracted from different human body parts （head, torso, and legs）, then a weighted algorithm is used to compute the similarity distance of two people. Finally, a similarity sorting algorithm with two thresholds is exploited to find the correspondence. The spatio- temporal information is established in the learning phase and is updated incrementally according to the latest correspondence. The experimental results prove that the proposed human tracking method is effective without requiring camera calibration and it becomes more accurate over time as new observations are accumulated.
基金The National Natural Science Foundation of China(No.60972001)the Science and Technology Plan of Suzhou City(No.SS201223)
文摘An adaptive topology learning approach is proposed to learn the topology of a practical camera network in an unsupervised way. The nodes are modeled by the Gaussian mixture model. The connectivity between nodes is judged by their cross-correlation function, which is also used to calculate their transition time distribution. The mutual information of the connected node pair is employed for transition probability calculation. A false link eliminating approach is proposed, along with a topology updating strategy to improve the learned topology. A real monitoring system with five disjoint cameras is built for experiments. Comparative results with traditional methods show that the proposed method is more accurate in topology learning and is more robust to environmental changes.
基金Supported by the National Natural Science Foundation of China （61074153, 61104131）, and the Fundamental Research Funds for Central Universities of China （ZY1111, JD1104）.
文摘New approaches for facility distribution in chemical plants are proposed including an improved non-overlapping constraint based on projection relationships of facilities and a novel toxic gas dispersion constraint. In consideration of the large number of variables in the plant layout model, our new method can significantly reduce the number of variables with their own projection relationships. Also, as toxic gas dispersion is a usual incident in a chemical plant, a simple approach to describe the gas leakage is proposed, which can clearly represent the constraints of potential emission source and sitting facilities. For solving the plant layout model, an improved genetic algorithm (GA) based on infeasible solution fix technique is proposed, which improves the globe search ability of GA. The case study and experiment show that a better layout plan can be obtained with our method, and the safety factors such as gas dispersion and minimum distances can be well handled in the solution.
基金Project(2011CB013504)supported by the National Basic Research Program(973 Program)of ChinaProject(2013BAB06B01)supported by Key Projects in the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period,China+1 种基金Projects(51309089,51479049)supported by National Natural Science Foundation of ChinaProject(487237)supported by Natural Sciences and Engineering Research Council of Canada
文摘Mechanical behaviors of granular materials are complicated and greatly influenced by the particle shape.Current,some composite approaches have been proposed for realistic particle shape modelling within discrete element method(DEM),while they cannot give a good representation to the shape and mass properties of a real particle.In this work,a novel algorithm is developed to model an arbitrary particle using a cluster of non-overlapping disks.The algorithm mainly consists of two components:boundary filling and domain filling.In the boundary filling,some disks are placed along the boundary for a precise representation of the particle shape,and some more disks are placed in the domain to give an approximation to the mass properties of the particle in the domain filling.Besides,a simple method is proposed to correct the mass properties of a cluster after domain filling and reduce the number of the disks in a cluster for lower computational load.Moreover,it is another great merit of the algorithm that a cluster generated by the algorithm can be used to simulate the particle breakage because of no overlaps between the disks in a cluster.Finally,several examples are used to show the robust performance of the algorithm.A current FORTRAN version of the algorithm is available by contacting the author.
基金funded by the Natural Science Foundation of Jiangsu Province(No.BK2012389)the National Natural Science Foundation of China(Nos.71303110,91024024)the Foundation of Graduate Innovation Center in NUAA(Nos.kfjj201471,kfjj201473)
文摘To track human across non-overlapping cameras in depression angles for applications such as multi-airplane visual human tracking and urban multi-camera surveillance,an adaptive human tracking method is proposed,focusing on both feature representation and human tracking mechanism.Feature representation describes individual by using both improved local appearance descriptors and statistical geometric parameters.The improved feature descriptors can be extracted quickly and make the human feature more discriminative.Adaptive human tracking mechanism is based on feature representation and it arranges the human image blobs in field of view into matrix.Primary appearance models are created to include the maximum inter-camera appearance information captured from different visual angles.The persons appeared in camera are first filtered by statistical geometric parameters.Then the one among the filtered persons who has the maximum matching scale with the primary models is determined to be the target person.Subsequently,the image blobs of the target person are used to update and generate new primary appearance models for the next camera,thus being robust to visual angle changes.Experimental results prove the excellence of the feature representation and show the good generalization capability of tracking mechanism as well as its robustness to condition variables.
文摘A boundary element method based on non-overlapping domain decomposition method to solve the time-dependent diffusion equations is presented. The time-dependent fundamental solution is used in the formulation of boundary integrals and the time integration process always restarts from the initial time condition. The process of replacing the interface values, which needs a summation of boundary integrals related to the boundary values at previous time steps can be treated in parallel iterative procedure. Numerical experiments demonstrate that the implementation of the present algorithm is efficient.
基金supported in part by Shanxi Scholarship Council of China(Grant No.2017-key-2)the Natural Science Foundation of Shanxi Province(Grant No.201801D121145)+1 种基金the Natural Science Foundation of China(NSFC)(Grant No.61731014,61705157,61927811)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams。
文摘NIST(National Institute of Standards and Technology) statistical test recognized as the most authoritative is widely used in verifying the randomness of binary sequences. The Non-overlapping Template Matching Test as the 7 th test of the NIST Test Suit is remarkably time consuming and the slow performance is one of the major hurdles in the testing process. In this paper, we present an efficient bit-parallel matching algorithm and segmented scan-based strategy for execution on Graphics Processing Unit(GPU) using NVIDIA Compute Unified Device Architecture(CUDA). Experimental results show the significant performance improvement of the parallelized Non-overlapping Template Matching Test, the running speed is 483 times faster than the original NIST implementation without attenuating the test result accuracy.
文摘BACKGROUND Elderly patients undergoing laparoscopic colorectal cancer surgery are at high risk for hypothermia-related complications.This study explores the efficacy of periop-erative composite insulation interventions in maintaining normothermia and reducing postoperative risks in this vulnerable group.AIM To evaluate the efficacy of perioperative composite insulation in older patients undergoing colorectal cancer surgery.METHODS We selected 100 older patients who underwent laparoscopic surgery for colorectal cancer at Huzhou Central Hospital from September 2023 to April 2024.Using a random number table,patients were divided into a control group and inter-vention group of 50 patients each.After returning to the regular ward,the con-ventional group received traditional insulation intervention measures,while the intervention group received composite insulation nursing intervention.We ob-served and recorded postoperative blood pressure and heart rate changes,as well as postoperative anesthesia recovery time and incidence of complications.RESULTS The statistical results showed significant differences(P<0.05)in heart rate changes and systolic blood pressure between the two groups.There was a sig-nificant change in heart rate between the groups immediately after surgery and at 15 and 30 minutes after surgery(P<0.05).The heart rate and systolic blood pressure of the intervention group were significantly lower than those of the control group at 15 and 30 minutes after surgery(P<0.05).The rewarming time of the intervention group was shorter than that of the control group,and the overall incidence of postoperative complications was significantly lower than that of the control group(P<0.05).CONCLUSION For elderly patients undergoing laparoscopic colorectal cancer surgery,a composite insulation intervention during the perioperative period can maintain body temperature,reduce postoperative stress,and significantly reduce the incidence of hypothermia and related complications.
文摘ADER-WAF methods were first introduced by researchers E.F. Toro and V.A. Titarev. The linear stability criterion for the model equation for the ADER-WAF schemes is CCFL≤1, where CCFLdenotes the Courant-Friedrichs-Lewy (CFL) coefficient. Toro and Titarev employed CCFL=0.95for their experiments. Nonetheless, we noted that the experiments conducted in this study with CCFL=0.95produced solutions exhibiting spurious oscillations, particularly in the high-order ADER-WAF schemes. The homogeneous one-dimensional (1D) non-linear Shallow Water Equations (SWEs) are the subject of these experiments, specifically the solution of the Riemann Problem (RP) associated with the SWEs. The investigation was conducted on four test problems to evaluate the ADER-WAF schemes of second, third, fourth, and fifth order of accuracy. Each test problem constitutes a RP characterized by different wave patterns in its solution. This research has two primary objectives. We begin by illustrating the procedure for implementing the ADER-WAF schemes for the SWEs, providing the required relations. Afterward, following comprehensive testing, we present the range for the CFL coefficient for each test that yields solutions with diminished or eliminated spurious oscillations.
基金supported by the National Natural Science Foundation of China(Grant No.11925204).
文摘In this paper,we develop a fourth-order conservative wavelet-based shock-capturing scheme.The scheme is constructed by combining a wavelet collocation upwind method with the monotonic tangent of hyperbola for interface capturing(THINC)technique.We employ boundary variation diminishing(BVD)reconstruction to enhance the scheme’s effectiveness in handling shocks.First,we prove that wavelet collocation upwind schemes based on interpolating wavelets can be reformulated into a conservative form within the framework of wavelet theory,forming the foundation of the proposed scheme.The new fourthorder accurate scheme possesses significantly better spectral resolution than the fifth-and even seventh-order WENO-Z(weighted essentially non-oscillatory)schemes over the entire wave-number range.Moreover,the inherent low-pass filtering property of the wavelet bases allows them to filter high-frequency numerical oscillations,endowing the wavelet upwind scheme with robustness and accuracy in solving problems under extreme conditions.Notably,due to the wavelet multiresolution approximation,the proposed scheme possesses a distinctive shape-preserving property absent in the WENO-Z schemes and the fifth-order schemes with BVD reconstruction based on polynomials.Furthermore,compared to the fifth-order scheme with BVD reconstruction based on polynomials—which is significantly superior to the WENO schemes—the proposed scheme further enhances the ability to capture discontinuities.
基金financially supported by the National Key Research and Development Program of China(No.2021YFC3000802)supported by the ECNU Multifunctional Platform for Innovation(001).
文摘This study investigates the capabilities of a non-hydrostatic global,variable-resolution model in simulating tropical cyclone precipitation,with historically significant Typhoon Fitow(1323)as a case study.Employing three grid settings(24 km,60−10 km,60−3 km)and two microphysical parameterization schemes(WSM6 and Thompson),the study investigates the influence of grid resolution and microphysical parameterization on precipitation simulation.The simulated precipitation intensity and spatial distribution of high-resolution grids exhibit better agreement with the observations compared to the coarse-resolution grids.Specifically,the 60−3 km grid setting shows the greatest improvement in spatial correlation with observed precipitation data compared to the 24 km grid.Through the analysis of the thermal dynamic field,the high-resolution grid configuration more effectively simulates indicators for strong convective weather events,such as convective available potential energy(CAPE),helicity,and nonadiabatic heating.Analysis of TRMM satellite observations reveals that the high-resolution grid simulation results more accurately capture the distribution characteristics of hydrometeor mixing ratio compared to the coarse-resolution grids.Differences in hydrometeor content within convective clouds are more pronounced across grid resolutions than in stratiform clouds,even with the same parameterization scheme.Additionally,at the same resolution,the disparity in ice-phase particle content between the two schemes is much greater than the disparity in liquid-phase particle content.It is also noteworthy that the WSM6 scheme delivers superior performance compared to the Thompson scheme.In summary,this study demonstrates that refining model resolution has a more significant impact on precipitation intensity than the selection of physical parameterization scheme.The Model for Prediction Across Scales(MPAS),using a high-resolution variable-resolution grid,can be effectively used for typhoon precipitation simulation research.
基金sponsored by the National Natural Science Foundation of China(U2442601 and U2442218)the High Performance Computing Platform of Nanjing University of Information Science&Technology(NUIST)for their support of this work。
文摘Numerical models play an important role in convective-scale forecasting,and dual-polarization radar observations can provide detailed microphysical data.In this study,we implement a direct assimilation operator for dual-polarization radar data using the hydrometeor background error covariance(HBEC)in the China Meteorological Administration MESO-scale weather forecasting system(CMA-MESO,formerly GRAPES-MESO)and conducted assimilation and forecasting experiments with X-band and S-band dual-polarization radar data on two cases.The results indicate that the direct assimilation of dual-polarization radar data enhanced the microphysical fields and the thermodynamic structure of convective systems to some extent based on the HBEC,thereby improving precipitation forecasts.Among the sensitivity tests of microphysical parameterization schemes,including the LIUMA scheme,the THOMPSON scheme,and the WSM6scheme(WRF Single-Moment 6-class),we find that the greatest improvement in the equivalent potential temperature,relative humidity,wind,and accumulated precipitation forecasts occurred in the experiment using the WSM6 scheme,as the distribution of solid precipitation particles was closer to the hydrometeor classification algorithm from the dualpolarization radar observations in our cases.
基金Science and Technology Research Project of Guang-dong Meteorological Bureau(GRMC2022M21)Guangdong Basic and Applied Basic Research Foundation(2023A1515012240)Research Project of Guangzhou Meteor-ological Bureau(M202218)。
文摘Reasonable greening design can effectively alleviate campus heat environment issues.This study uses the ENVI-met numerical model,along with in-situ observations and simulations,to analyze the thermal environment under three different greening schemes in typical areas of the Guangzhou University campus.The results indicate that the outdoor thermal environment is significantly influenced by the underlying surface materials and vegetation.The temperature of brick-paved surface is 0.9℃higher than that of natural soil surfaces under tree shade.Numerical simulations further confirm that increasing vegetation coverage effectively reduces outdoor air temperature.When the greening rate increases to 40%,the outdoor average temperature decreases by 0.7℃and relative humidity increases by approximately 4%,while wind speed remains minimal change.The cooling effect of vegetation is found to extend vertically to an altitude of 13 m.As the greening rate increases from 15%to 40%,the Mean Radiant Temperature(MRT)decreases from 50.6℃to 28.9℃,which is lower than the average ambient temperature,indicating improved thermal conditions.The Physiological Equivalent Temperature(PET)decreases from 40.2℃to 30.0℃,with the proportion of the areas classified as″very hot″reducing by 36.8%,significantly improving thermal comfort across most areas.Therefore,changing the ground material and greening landscape design can effectively alter the outdoor wind and thermal environment of the campus,thereby enhancing the thermal comfort for the campus community.
基金supported by the National Natural Science Foundation of China(Grant Nos.41975090,U2242201,42075077)the Natural Science Foundation of Hunan Province,China(2022JJ20043)the Science and Technology Innovation Program of Hunan Province,China(2022RC1239)。
文摘In this study,the Betts-Miller-Janjic(BMJ)convective adjustment scheme in the Weather Research and Forecasting(WRF)model version 4.0 was used to investigate the effect of itsα-parameter,which influences the first-guess potential temperature reference profile on the Madden-Julian oscillation(MJO)propagation and structure.This study diagnosed the MJO active phase composites of the MJO-filtered outgoing longwave radiation(OLR)during the December-to-February(DJF)period of 2006-2016 over the Indian Ocean(IO),Maritime Continent(MC),and western Pacific(WP).The results show that the MJO-filtered OLR intensity,propagation pattern,and MJO classification(standing,jumping,and propagating clusters)are sensitive to theα-value,but the phase speeds of propagating MJOs are not.Overall,with an increasingα-value,the simulated MJO-filtered OLR intensity increases,and the simulated propagation pattern is improved.Results also show that the intensity and propagation pattern of an eastward-propagating MJO are associated with MJO circulation structures and thermodynamic structures.Asαincreases,the front Walker cell and the low-level easterly anomaly are enhanced,which premoistens the lower troposphere and triggers more active shallow and congestus clouds.The enhanced shallow and congestus convection preconditions the lower to middle troposphere,accelerating the transition from congestus to deep convection,thereby facilitating eastward propagation of the MJO.Therefore,the simulated MJO tends to transfer from standing to eastward propagating asαincreases.In summary,increasing theα-value is a possible way to improve the simulation of the structure and propagation of the MJO.
基金supported by the National Key R&D Program of China(Grant No.2023YFB3407103)the National Natural Science Foundation of China(Grant Nos.52175242 and 52175027)Young Elite Scientists Sponsorship Program by China Association for Science and Technology(Grant No.2022QNRC001).
文摘Mesh reflector antennas are the mainstream of large space-borne antennas,and the stretching of the truss achieves their deployment.Currently,the truss is commonly designed to be a single degree of freedom(DOF)deployable mechanism with synchronization constraints.However,each deployable unit’s drive distribution and resistance load are uneven,and the forced synchronization constraints lead to the flexible deformation of rods and difficulties in the deployment scheme design.This paper introduces an asynchronous deployment scheme with a multi-DOF closed-chain deployable truss.The DOF of the truss is calculated,and the kinematic and dynamic models are established,considering the truss’s and cable net’s real-time coupling.An integrated solving algorithm for implicit differential-algebraic equations is proposed to solve the dynamic models.A prototype of a six-unit antenna was fabricated,and the experiment was carried out.The dynamic performances in synchronous and asynchronous deployment schemes are analyzed,and the results show that the cable resistance and truss kinetic energy impact under the asynchronous deployment scheme are minor,and the antenna is more straightforward to deploy.The work provides a new asynchronous deployment scheme and a universal antenna modeling method for dynamic design and performance improvement.
文摘The implementation of core competencies clarifies social talent needs and guides math classroom evaluation.Lower-grade primary students,highly malleable,need targeted teacher guidance.Teaching evaluation should meet the talent demands of the times,focusing on core literacy and essential character development.From this perspective,primary math teachers should optimize evaluation,build a diversified system,help students grow in math,find their learning position,and advance confidently.
基金the financial support from Intergovernmental International Science and Technology Innovation Cooperation Key Project(2022YFE0128400)National Natural Science Foundation of China(42307209)+2 种基金Shanghai Pujiang Program(2022PJD076)State Energy Center for Shale Oil Research and Development(33550000-22-ZC0613-0365)Natural Science Foundation of Qinghai Province(No.2024-ZJ-717).
文摘Shale oil reservoir is generally characterized by well-developed bedding planes,and multi-cluster fracturing is the most effective technique to achieve stable shale oil production.In this paper,a multi-cluster fracturing model for a horizontal well in shale with high-density bedding planes is established.The fracture morphology,fracture geometry,fracturing area and multiple fracture propagation mechanism are analyzed under simultaneous fracturing,sequential fracturing,and alternative fracturing.Results show that in the case of small cluster spacing and three clusters,the growth of the middle fracture is inhibited and develops along the bedding planes under both simultaneous fracturing and alternative fracturing.For sequential fracturing,the increase in the interval time between each fracturing advances the post fracturing fracture deflecting to the pre-existing fractures through the bedding planes.The reactivation of the bedding planes can promote the extension of the fracturing area.Increasing the injection rate and the number of clusters promotes the activation of bedding planes.However,it is preferable to reduce the number of clusters to obtain more main fractures.Compared with modified alternating fracturing and cyclic alternating fracturing,alternating shut-in fracturing creates more main fractures towards the direction of the maximum in-situ stress.The fracturing efficiency for high-density layered shale is ranked as simultaneous fracturing>alternative fracturing>sequential fracturing.
基金supported by the National Natural Science Foundation of China(Nos.52107126 and52077179)the Key Regional Innovation and Development Joint Fund Project(No.2023YFB2303901)the funding of Chengdu Guojia Electrical Engineering Co.,Ltd.(No.NEEC-2022-B11).
文摘The regenerative braking energy utilization system(RBEUS)stands as a promising technique for improving the efficiency and power quality of electrified railways.Beyond the vital aspects of energy management and control strategies,ensuring fault protection is paramount for the secure and steady operation of the traction power supply system(TPSS)integrated with RBEUS.This paper introduces an innovative protection scheme tailored to diverse RBEUS application scenarios.Firstly,fault categories are streamlined into three levels:system,equipment,and warning.Subsequently,a novel multi-port active power differential protection method,aligned with RBEUS operational principles,is crafted to serve as a comprehensive and sensitive main protection.Building upon this foundation,a hierarchical protection structure for RBEUS is established,addressing the intricacies and variations in fault types while boosting anti-disturbance capabilities under faulty conditions.Embracing the principle of railway-oriented safety,a collaborative RBEUS-TPSS protection scheme is put forth.Finally,through simulated scenarios encompassing various fault conditions,the proposed scheme’s feasibility and effectiveness are convincingly validated.
文摘International carbon tax issues such as carbon leakage and carbon neutralization have become major topics of social concern.Based on the practical experience of carbon tax system in individual countries,this paper integrates the existing research of international carbon tax scholars to the classification and comparative analysis of international carbon tax schemes.Using a literature review approach,this dissertation mainly applies the method of qualitative analysis to explain and compare the contents of four international carbon tax options.Through the analysis and evaluation of individual countries’carbon tax practice,the two-country model is verified.Through the method of comparative analysis,the schemes are evaluated from four dimensions and an assessment is made.The difference of carbon tax among countries makes the internal policies of countries adjust accordingly with the changes of international environment,which promotes the gradual convergence of carbon tax schemes.The results intend to provide reference to further study the issue on international carbon tax.
