This research has objective to analyze some tools which are used to support decision maker to make a decision in multi stage and systematic way. And also in making decision, there are a qualitative type and quantitati...This research has objective to analyze some tools which are used to support decision maker to make a decision in multi stage and systematic way. And also in making decision, there are a qualitative type and quantitative type. In order to get an optimum decision making, the decision maker needs systematic way. There is the frame work which is based on combination of some existing methods and challenges emerging in organizational activities, including social organizations as well as business organisations. To formulate the framework, this research conducted focus group discussion consisting of some organizational managers as participants. There are five components of proposed frame work： （1） Criteria Identification through Focus Group Discussion （FGD）; （2） Criteria Selection; （3） Focus Group for Criteria Verification; （4） Multicriteria Decision Making based Analytic Hierarchy Process （AHP）; and （5） Impact Analysis. This research resulted in an effective approach of decision making which allows decision maker to have objective and rational reason in each step of its decision-making process. Strength of the proposed framework is to provide rational and objective approach in group decision making. However, it takes longer time to conduct decision making due to more steps and participants involved. As a conclusion, the proposed research has been successful in establishing a multi stage and rational decision-making process.展开更多
Introduction: In emergence a COVID patient with multisystem inflammatory syndrome in children (MIS-C), associated with SARS-CoV-2, has shown increasing number among pediatric. Even the same presentation of Kawasaki di...Introduction: In emergence a COVID patient with multisystem inflammatory syndrome in children (MIS-C), associated with SARS-CoV-2, has shown increasing number among pediatric. Even the same presentation of Kawasaki disease we have to keep in mind MIS-C, in order to reach a consensus on this new disease in the future. Three variations of the disease patterns were reported: a group of children with increase in inflammatory activity and persistent fever, without criteria for Kawasaki disease, a second group with Kawasaki disease criteria, and a third group with shock, coronary aneurysms, severe cardiac dysfunction, and gastrointestinal symptoms. Classic Kawasaki disease is self-limited vasculitis which affects medium-sized vessels, almost occurred in children under five years old. Here, we bring a Saudi case, present to emergency department in Prince Sultan Military Medical City. Case report: 10 years old female, medically free, presented with abdominal pain, fever and skin rashes. Patient had history of COVID-19 infection 1 month before presentation. Initial investigations showed acute kidney injury with elevated inflammatory markers. Conclusion: Further evidence of the increase in the incidence of pediatric MIS-C, temporarily is associated with SARS-CoV-2. Physician should give more attentions to this new diagnosis with more fatal outcomes than Kawasaki cases.展开更多
The aim of this study was to report a case of multi-visceral sarcoidosis at the Mother-Child Hospital Center (CHME) “Le Luxembourg” in Bamako, Mali. Observation: This is a patient aged 62 at the time of consultation...The aim of this study was to report a case of multi-visceral sarcoidosis at the Mother-Child Hospital Center (CHME) “Le Luxembourg” in Bamako, Mali. Observation: This is a patient aged 62 at the time of consultation, a housewife, residing in the Banconi district, who was referred to us for thoracic-abdominopelvic imaging for chronic liver disease. After several diagnostic errors, the thoracic-abdominopelvic CT scan and liver MRI performed in our center showed, at the thoracoabdominal level, bilateral diffuse pulmonary micronodules and bilateral mediastinal-hilar lymphadenopathy;on the abdominal level, a dysmorphic liver with plaques of steatosis and a granular appearance of the liver parenchyma without periportal fibrosis. These imaging data combined with those from the liver nodule biopsy and biology confirmed the diagnosis of sarcoidosis type II. Treatment with corticosteroids gave satisfactory results and the patient recovered after 18 months. Clinical and CT monitoring 2 years from the start of the disease and 2 months from the end of treatment showed complete resolution of the lesions. Conclusion: The multi-visceral location of sarcoidosis is an entity whose diagnosis remains difficult;diagnostic and interventional imaging has an important place in its management.展开更多
Multi-spectral and multi-functional optical components play a crucial role in fields such as high-speed communications and optical sensing.However,the interaction between different spectra and matter varies significan...Multi-spectral and multi-functional optical components play a crucial role in fields such as high-speed communications and optical sensing.However,the interaction between different spectra and matter varies significantly,making it challenging to simultaneously achieve dynamic multi-spectral modulation capabilities.We designed a modulator based on a planar nested multiscale metasurface,incorporating silicon(Si)and perovskite as control materials,to modulate both microwave and terahertz(THz)ranges.展开更多
Soil science has remained basically an agricultural science since its establishment more than a century ago.However,given its multi-dimensional connections with human society and multi-functions and services to be uti...Soil science has remained basically an agricultural science since its establishment more than a century ago.However,given its multi-dimensional connections with human society and multi-functions and services to be utilized in the future,the theoretical and technological boundary of soil science is expanding from agricultural science to newly emerged soil science sectors,which can be termed as nontraditional soil science.To build a more comprehensive and up-to-date soil science system,new description methods,recommendation standards,interpretation principles,and criteria for non-agricultural applications should be developed.展开更多
The multi-objective optimization problems,especially in constrained environments such as power distribution planning,demand robust strategies for discovering effective solutions.This work presents the improved variant...The multi-objective optimization problems,especially in constrained environments such as power distribution planning,demand robust strategies for discovering effective solutions.This work presents the improved variant of the Multi-population Cooperative Constrained Multi-Objective Optimization(MCCMO)Algorithm,termed Adaptive Diversity Preservation(ADP).This enhancement is primarily focused on the improvement of constraint handling strategies,local search integration,hybrid selection approaches,and adaptive parameter control.Theimproved variant was experimented on with the RWMOP50 power distribution systemplanning benchmark.As per the findings,the improved variant outperformed the original MCCMO across the eleven performance metrics,particularly in terms of convergence speed,constraint handling efficiency,and solution diversity.The results also establish that MCCMOADP consistently delivers substantial performance gains over the baseline MCCMO,demonstrating its effectiveness across performancemetrics.The new variant also excels atmaintaining the balanced trade-off between exploration and exploitation throughout the search process,making it especially suitable for complex optimization problems in multiconstrained power systems.These enhancements make MCCMO-ADP a valuable and promising candidate for handling problems such as renewable energy scheduling,logistics planning,and power system optimization.Future work will benchmark the MCCMO-ADP against widely recognized algorithms such as NSGA-Ⅱ,NSGA-Ⅲ,and MOEA/D and will also extend its validation to large-scale real-world optimization domains to further consolidate its generalizability.展开更多
The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration...The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration of rotorcraft.The aerodynamic interaction of tandem tilt-wing and multi-rotor is investigated based on the CFD method.The aerodynamic effect of multi tilt-rotor is simulated as virtual disk modeling by adding source terms to the Navier-Stokes equations,effectively reducing the calculation time while maintaining the accuracy of aerodynamic interaction calculations.Aerodynamic forces and flow field characteristics of the tandem tilt-wing and multi-rotor under different tilt angles are compared between cases with and without aerodynamic interaction.Furthermore,the differences in aerodynamic forces between dynamic tilt transition and fixed-angle conditions were compared.The results show that the aerodynamic interaction of multi-rotor obviously increases the lift of front tilt-wing at different tilt angles,the wing lift under interaction is increased by more than 40%compared with isolated wing at tilt angle of 15°for the computation in this paper,which is related to the increase of wing flow velocity and the suppression of flow separation caused by multi-rotor;the wing blocking effect will increase rotor thrust,especially near the tilt angles of 30°and 45°;the increases of rear wing lift and rear rotor thrust under aerodynamic interaction are not significant because of suppression by the front wing’s downwash;the unsteady effects during dynamic tilting have a relatively minor impact on aerodynamic interaction,with the aerodynamic forces on the rotors and wings during the dynamic tilting process showing little difference from those under corresponding fixed tilt angles.展开更多
Here,each object from the three mysterious ancient kingdoms of the Dian,the Nanzhao,and the Dali tells the stories of a glorious past,and showcases the deep-rooted multi-ethnic culture of China.THE land of present-day...Here,each object from the three mysterious ancient kingdoms of the Dian,the Nanzhao,and the Dali tells the stories of a glorious past,and showcases the deep-rooted multi-ethnic culture of China.THE land of present-day Yunnan Province,known for year-round warm climate and breathtaking natural beauty,is the cradle of human civilization in southeast China,leaving an abundance of historical and cultural legacies.More than a thousand years ago,the mysterious ancient Dian Kingdom flourished here;centuries later came the Nanzhao and Dali kingdoms.展开更多
Regular detection of pavement cracks is essential for infrastructure maintenance.However,existing methods often ignore the challenges such as the continuous evolution of crack features between video frames and the dif...Regular detection of pavement cracks is essential for infrastructure maintenance.However,existing methods often ignore the challenges such as the continuous evolution of crack features between video frames and the difficulty of defect quantification.To this end,this paper proposes an integrated framework for pavement crack detection,segmentation,tracking and counting based on Transformer.Firstly,we design theVitSeg-Det network,which is an integrated detection and segmentation network that can accurately locate and segment tiny cracks in complex scenes.Second,the TransTra-Count system is developed to automatically count the number of defects by combining defect tracking with width estimation.Finally,we conduct experimental verification on three datasets.The results show that the proposed method is superior to the existing deep learning methods in detection accuracy.In addition,the actual scene video test shows that the framework can accurately label the defect location and output the number of defects in real time.展开更多
Researchers are increasingly focused on enabling groups of multiple unmanned vehicles to operate cohesively in complex,real-world environments,where coordinated formation control and obstacle avoidance are essential f...Researchers are increasingly focused on enabling groups of multiple unmanned vehicles to operate cohesively in complex,real-world environments,where coordinated formation control and obstacle avoidance are essential for executing sophisticated collective tasks.This paper presents a Distributed Formation Control and Obstacle Avoidance(DFCOA)framework for multi-unmanned ground vehicles(UGV).DFCOA integrates a virtual leader structure for global guidance,an improved A^(*)path planning algorithm with an advanced cost function for efficient path planning,and a repulsive-force-based improved vector field histogram star(VFH^(*))technique for collision avoidance.The virtual leader generates a reference trajectory while enabling distributed execution;the improved A^(*)algorithm reduces planning time and number of nodes to determine the shortest path from the starting position to the goal;and the improved VFH^(*)uses 2D LiDAR data with inter-agent repulsive force to simultaneously avoid collision with obstacles and maintain safe inter-vehicle distances.The formation stability of the proposed DFCOA reaches 95.8%and 94.6%in two scenarios,with root mean square(RMS)centroid errors of 0.9516 and 1.0008 m,respectively.Velocity tracking is precise(velocity centroid error RMS of 0.2699 and 0.1700 m/s),and linear velocities closely match the desired 0.3 m/s.Safety metrics showed average collision risks of 0.7773 and 0.5143,with minimum inter-vehicle distances of 0.4702 and 0.8763 m,confirming collision-free navigation of four UGVs.DFCOA outperforms conventional methods in formation stability,path efficiency,and scalability,proving its suitability for decentralized multi-UGV applications.展开更多
Accurate precipitation estimation in semiarid,topographically complicated areas is critical for water resource management and climate risk monitoring.This work provides a detailed,multi-scale evaluation of four major ...Accurate precipitation estimation in semiarid,topographically complicated areas is critical for water resource management and climate risk monitoring.This work provides a detailed,multi-scale evaluation of four major satellite precipitation products(CHIRPS,PERSIANN-CDR,IMERG-F v07,and GSMaP)over Isfahan province,Iran,over a 9-year period(2015-2023).The performance of these products was benchmarked against a dense network of 98 rain gauges using a suite of continuous and categorical statistical metrics,following a two-stage quality control protocol to remove outliers and false alarms.The results revealed that the performance of all products improves with temporal aggregation.At the daily level,GSMaP performed marginally better,although all products were linked with considerable uncertainty.At the monthly and annual levels,the GPM-era products(IMERG and GSMaP)clearly beat the other two,establishing themselves as dependable tools for long-term hydro-climatological studies.Error analysis revealed that topography is the dominant regulating factor,creating a systematic elevationdependent bias,largely characterized by underestimation from most products in high-elevation areas,though the PERSIANN-CDR product exhibited a contrasting overestimation tendency.Finally,the findings highlight the importance of implementing local,elevation-dependent calibration before deploying these products in hydrological modeling.展开更多
The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of...The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of high‐content graphene reinforcements.This compromise becomes particularly severe in composites with high‐content graphene reinforcements,whose agglomeration leads to embrittlement and lubrication failure.Here,a flake powder-metallurgy strategy is developed to construct a self‐assembled lamellar structure in graphene/CoCrNi MPEA composites(Gr/MPEA_(AL)).This approach enables the uniform dispersion of a high graphene content(3.0 wt%),which is unattainable by conventional methods.The resulting composite exhibits a rare dual enhancement in performance:an order‐of‐magnitude improvement in wear resistance coupled with a low coefficient of friction.Intriguingly,the tribological behavior shows significant anisotropy,with optimal performance observed when sliding perpendicular to the lamellae.Through a multi‐scale methodology combining molecular dynamics simulations,finite element analysis,and systematic experiments,it is revealed that this exceptional performance stems from the synergy of high‐density deformation nanotwins,efficient strain delocalization,and abundant graphene‐derived lubricating sites.This work establishes a general paradigm for designing composite architectures that reconcile traditionally incompatible properties,offering broad implications for developing next‐generation structural materials with integrated mechanical robustness and surface functionality for safety‐critical applications.展开更多
Background This study was conducted to investigate the impact of varying degrees of heat stress on milk protein synthesis in dairy cows using comprehensive analyses of metabolomics and proteomics.Eighteen dairy cows w...Background This study was conducted to investigate the impact of varying degrees of heat stress on milk protein synthesis in dairy cows using comprehensive analyses of metabolomics and proteomics.Eighteen dairy cows were subjected to no heat stress(No-HS),mild heat stress(Mild-HS),and moderate heat stress(Mod-HS).Blood and milk samples were collected to determine the content and composition of amino acids(AA),and milk samples were used for metabolomic and proteomic analyses.Results Milk protein yield was significantly lower under Mild-HS and Mod-HS than No-HS(P<0.001).During Mild-HS,no significant difference was found in total AA concentration in both arterial(P=0.545)and venous blood(P=0.057),but arterial AA supply to the mammary gland significantly increased(P=0.045)when compared with No-HS.Under Mod-HS,the supply(P<0.001)and uptake(P=0.001)of total AA in the mammary gland decreased significantly,affecting the availability of precursors necessary for milk protein synthesis.Milk metabolomic analysis revealed that Mod-HS significantly impacted nucleotide metabolism,energy metabolism,and protein synthesis processes including translation,folding,and transport.Milk proteomic analysis showed significant downregulation of ribosomal and heat shock proteins which are crucial for protein synthesis and folding.Conclusions These findings suggest that heat stress disrupts AA utilization and energy metabolism in the mammary gland,leading to the reduced efficiency in milk protein synthesis and lowered milk protein yield.This study offers valuable insights into the metabolic and proteomic changes in dairy cows under heat stress,highlighting potential strategies to mitigate the adverse effects of heat stress on dairy production and milk quality.展开更多
Description Journal of Integrative Agriculture(JIA),formerly Agricultural Sciences in China(ASC),founded in 2002,is sponsored by Chinese Academy of Agricultural Sciences(CAAS),co-sponsored by Chinese Association of Ag...Description Journal of Integrative Agriculture(JIA),formerly Agricultural Sciences in China(ASC),founded in 2002,is sponsored by Chinese Academy of Agricultural Sciences(CAAS),co-sponsored by Chinese Association of Agricultural Science Societies(CAASS).JIA is a peer-reviewed and multi-disciplinary international journal and published monthly in English.JIA Editorial Board consists of 289 well-respected scholars of agricultural scientific fields.CAAS President,Academician Kongming Wu is the Chairman of the Board,and Academician Hualan Chen is the Editor-in-Chief.JIA has been available online at ScienceDirect since 2006 and is a leading academic journal in agricultural sciences in China.As released by JCR,the latest IF of the journal is 4.4.展开更多
To address the issues of frequent identity switches(IDs)and degraded identification accuracy in multi object tracking(MOT)under complex occlusion scenarios,this study proposes an occlusion-robust tracking framework ba...To address the issues of frequent identity switches(IDs)and degraded identification accuracy in multi object tracking(MOT)under complex occlusion scenarios,this study proposes an occlusion-robust tracking framework based on face-pedestrian joint feature modeling.By constructing a joint tracking model centered on“intra-class independent tracking+cross-category dynamic binding”,designing a multi-modal matching metric with spatio-temporal and appearance constraints,and innovatively introducing a cross-category feature mutual verification mechanism and a dual matching strategy,this work effectively resolves performance degradation in traditional single-category tracking methods caused by short-term occlusion,cross-camera tracking,and crowded environments.Experiments on the Chokepoint_Face_Pedestrian_Track test set demonstrate that in complex scenes,the proposed method improves Face-Pedestrian Matching F1 area under the curve(F1 AUC)by approximately 4 to 43 percentage points compared to several traditional methods.The joint tracking model achieves overall performance metrics of IDF1:85.1825%and MOTA:86.5956%,representing improvements of 0.91 and 0.06 percentage points,respectively,over the baseline model.Ablation studies confirm the effectiveness of key modules such as the Intersection over Area(IoA)/Intersection over Union(IoU)joint metric and dynamic threshold adjustment,validating the significant role of the cross-category identity matching mechanism in enhancing tracking stability.Our_model shows a 16.7%frame per second(FPS)drop vs.fairness of detection and re-identification in multiple object tracking(FairMOT),with its cross-category binding module adding aboute 10%overhead,yet maintains near-real-time performance for essential face-pedestrian tracking at small resolutions.展开更多
Monitoring waterbirds is vital for evaluating the ecological health of wetlands,and object detection offers an automated solution for identifying birds in monitoring imagery.However,conventional detection methods ofte...Monitoring waterbirds is vital for evaluating the ecological health of wetlands,and object detection offers an automated solution for identifying birds in monitoring imagery.However,conventional detection methods often overlook the multi-scale nature of bird targets,limiting their ability to capture rich contextual information across different scales.To address this,we propose a cross-dimensional attention network(CDA-Net)for bird detection that integrates spatial and channel information to improve species recognition.The proposed CDA-Net partitions feature maps into multiple channel wise sub-features.Spatial and channel attention are applied to each subfeature,and the resulting features are fused using the Hadamard product.The fused features are then forwarded to the detection head to generate the final detection results.This approach effectively captures and integrates information across spatial and channel dimensions.Experiments on our self-constructed Nanhai Wetland Waterbird Dataset and the public CUB-200-2011 dataset yield precision scores of 91.32%and 81.99%,respectively,outperforming existing methods.Our approach effectively handles scale variation in bird detection and provides a valuable tool for advancing automated wetland waterbird monitoring.展开更多
文摘This research has objective to analyze some tools which are used to support decision maker to make a decision in multi stage and systematic way. And also in making decision, there are a qualitative type and quantitative type. In order to get an optimum decision making, the decision maker needs systematic way. There is the frame work which is based on combination of some existing methods and challenges emerging in organizational activities, including social organizations as well as business organisations. To formulate the framework, this research conducted focus group discussion consisting of some organizational managers as participants. There are five components of proposed frame work： （1） Criteria Identification through Focus Group Discussion （FGD）; （2） Criteria Selection; （3） Focus Group for Criteria Verification; （4） Multicriteria Decision Making based Analytic Hierarchy Process （AHP）; and （5） Impact Analysis. This research resulted in an effective approach of decision making which allows decision maker to have objective and rational reason in each step of its decision-making process. Strength of the proposed framework is to provide rational and objective approach in group decision making. However, it takes longer time to conduct decision making due to more steps and participants involved. As a conclusion, the proposed research has been successful in establishing a multi stage and rational decision-making process.
文摘Introduction: In emergence a COVID patient with multisystem inflammatory syndrome in children (MIS-C), associated with SARS-CoV-2, has shown increasing number among pediatric. Even the same presentation of Kawasaki disease we have to keep in mind MIS-C, in order to reach a consensus on this new disease in the future. Three variations of the disease patterns were reported: a group of children with increase in inflammatory activity and persistent fever, without criteria for Kawasaki disease, a second group with Kawasaki disease criteria, and a third group with shock, coronary aneurysms, severe cardiac dysfunction, and gastrointestinal symptoms. Classic Kawasaki disease is self-limited vasculitis which affects medium-sized vessels, almost occurred in children under five years old. Here, we bring a Saudi case, present to emergency department in Prince Sultan Military Medical City. Case report: 10 years old female, medically free, presented with abdominal pain, fever and skin rashes. Patient had history of COVID-19 infection 1 month before presentation. Initial investigations showed acute kidney injury with elevated inflammatory markers. Conclusion: Further evidence of the increase in the incidence of pediatric MIS-C, temporarily is associated with SARS-CoV-2. Physician should give more attentions to this new diagnosis with more fatal outcomes than Kawasaki cases.
文摘The aim of this study was to report a case of multi-visceral sarcoidosis at the Mother-Child Hospital Center (CHME) “Le Luxembourg” in Bamako, Mali. Observation: This is a patient aged 62 at the time of consultation, a housewife, residing in the Banconi district, who was referred to us for thoracic-abdominopelvic imaging for chronic liver disease. After several diagnostic errors, the thoracic-abdominopelvic CT scan and liver MRI performed in our center showed, at the thoracoabdominal level, bilateral diffuse pulmonary micronodules and bilateral mediastinal-hilar lymphadenopathy;on the abdominal level, a dysmorphic liver with plaques of steatosis and a granular appearance of the liver parenchyma without periportal fibrosis. These imaging data combined with those from the liver nodule biopsy and biology confirmed the diagnosis of sarcoidosis type II. Treatment with corticosteroids gave satisfactory results and the patient recovered after 18 months. Clinical and CT monitoring 2 years from the start of the disease and 2 months from the end of treatment showed complete resolution of the lesions. Conclusion: The multi-visceral location of sarcoidosis is an entity whose diagnosis remains difficult;diagnostic and interventional imaging has an important place in its management.
基金National Natural Science Foundation of China(61975046,62375068)。
文摘Multi-spectral and multi-functional optical components play a crucial role in fields such as high-speed communications and optical sensing.However,the interaction between different spectra and matter varies significantly,making it challenging to simultaneously achieve dynamic multi-spectral modulation capabilities.We designed a modulator based on a planar nested multiscale metasurface,incorporating silicon(Si)and perovskite as control materials,to modulate both microwave and terahertz(THz)ranges.
基金supported by the National Natural Science Foundation of China(No.42130715)the National Key Research and Development Program of China(No.2023YFD1500101)。
文摘Soil science has remained basically an agricultural science since its establishment more than a century ago.However,given its multi-dimensional connections with human society and multi-functions and services to be utilized in the future,the theoretical and technological boundary of soil science is expanding from agricultural science to newly emerged soil science sectors,which can be termed as nontraditional soil science.To build a more comprehensive and up-to-date soil science system,new description methods,recommendation standards,interpretation principles,and criteria for non-agricultural applications should be developed.
文摘The multi-objective optimization problems,especially in constrained environments such as power distribution planning,demand robust strategies for discovering effective solutions.This work presents the improved variant of the Multi-population Cooperative Constrained Multi-Objective Optimization(MCCMO)Algorithm,termed Adaptive Diversity Preservation(ADP).This enhancement is primarily focused on the improvement of constraint handling strategies,local search integration,hybrid selection approaches,and adaptive parameter control.Theimproved variant was experimented on with the RWMOP50 power distribution systemplanning benchmark.As per the findings,the improved variant outperformed the original MCCMO across the eleven performance metrics,particularly in terms of convergence speed,constraint handling efficiency,and solution diversity.The results also establish that MCCMOADP consistently delivers substantial performance gains over the baseline MCCMO,demonstrating its effectiveness across performancemetrics.The new variant also excels atmaintaining the balanced trade-off between exploration and exploitation throughout the search process,making it especially suitable for complex optimization problems in multiconstrained power systems.These enhancements make MCCMO-ADP a valuable and promising candidate for handling problems such as renewable energy scheduling,logistics planning,and power system optimization.Future work will benchmark the MCCMO-ADP against widely recognized algorithms such as NSGA-Ⅱ,NSGA-Ⅲ,and MOEA/D and will also extend its validation to large-scale real-world optimization domains to further consolidate its generalizability.
基金supported by the National Key Laboratory of Helicopter Aeromechanics Fund(No.2024-CXPT-GF-JJ-093-05).
文摘The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration of rotorcraft.The aerodynamic interaction of tandem tilt-wing and multi-rotor is investigated based on the CFD method.The aerodynamic effect of multi tilt-rotor is simulated as virtual disk modeling by adding source terms to the Navier-Stokes equations,effectively reducing the calculation time while maintaining the accuracy of aerodynamic interaction calculations.Aerodynamic forces and flow field characteristics of the tandem tilt-wing and multi-rotor under different tilt angles are compared between cases with and without aerodynamic interaction.Furthermore,the differences in aerodynamic forces between dynamic tilt transition and fixed-angle conditions were compared.The results show that the aerodynamic interaction of multi-rotor obviously increases the lift of front tilt-wing at different tilt angles,the wing lift under interaction is increased by more than 40%compared with isolated wing at tilt angle of 15°for the computation in this paper,which is related to the increase of wing flow velocity and the suppression of flow separation caused by multi-rotor;the wing blocking effect will increase rotor thrust,especially near the tilt angles of 30°and 45°;the increases of rear wing lift and rear rotor thrust under aerodynamic interaction are not significant because of suppression by the front wing’s downwash;the unsteady effects during dynamic tilting have a relatively minor impact on aerodynamic interaction,with the aerodynamic forces on the rotors and wings during the dynamic tilting process showing little difference from those under corresponding fixed tilt angles.
文摘Here,each object from the three mysterious ancient kingdoms of the Dian,the Nanzhao,and the Dali tells the stories of a glorious past,and showcases the deep-rooted multi-ethnic culture of China.THE land of present-day Yunnan Province,known for year-round warm climate and breathtaking natural beauty,is the cradle of human civilization in southeast China,leaving an abundance of historical and cultural legacies.More than a thousand years ago,the mysterious ancient Dian Kingdom flourished here;centuries later came the Nanzhao and Dali kingdoms.
基金supported in part by the Natural Science Foundation of Shaanxi Province of China under Grant 2024JC-YBQN-0695.
文摘Regular detection of pavement cracks is essential for infrastructure maintenance.However,existing methods often ignore the challenges such as the continuous evolution of crack features between video frames and the difficulty of defect quantification.To this end,this paper proposes an integrated framework for pavement crack detection,segmentation,tracking and counting based on Transformer.Firstly,we design theVitSeg-Det network,which is an integrated detection and segmentation network that can accurately locate and segment tiny cracks in complex scenes.Second,the TransTra-Count system is developed to automatically count the number of defects by combining defect tracking with width estimation.Finally,we conduct experimental verification on three datasets.The results show that the proposed method is superior to the existing deep learning methods in detection accuracy.In addition,the actual scene video test shows that the framework can accurately label the defect location and output the number of defects in real time.
文摘Researchers are increasingly focused on enabling groups of multiple unmanned vehicles to operate cohesively in complex,real-world environments,where coordinated formation control and obstacle avoidance are essential for executing sophisticated collective tasks.This paper presents a Distributed Formation Control and Obstacle Avoidance(DFCOA)framework for multi-unmanned ground vehicles(UGV).DFCOA integrates a virtual leader structure for global guidance,an improved A^(*)path planning algorithm with an advanced cost function for efficient path planning,and a repulsive-force-based improved vector field histogram star(VFH^(*))technique for collision avoidance.The virtual leader generates a reference trajectory while enabling distributed execution;the improved A^(*)algorithm reduces planning time and number of nodes to determine the shortest path from the starting position to the goal;and the improved VFH^(*)uses 2D LiDAR data with inter-agent repulsive force to simultaneously avoid collision with obstacles and maintain safe inter-vehicle distances.The formation stability of the proposed DFCOA reaches 95.8%and 94.6%in two scenarios,with root mean square(RMS)centroid errors of 0.9516 and 1.0008 m,respectively.Velocity tracking is precise(velocity centroid error RMS of 0.2699 and 0.1700 m/s),and linear velocities closely match the desired 0.3 m/s.Safety metrics showed average collision risks of 0.7773 and 0.5143,with minimum inter-vehicle distances of 0.4702 and 0.8763 m,confirming collision-free navigation of four UGVs.DFCOA outperforms conventional methods in formation stability,path efficiency,and scalability,proving its suitability for decentralized multi-UGV applications.
文摘Accurate precipitation estimation in semiarid,topographically complicated areas is critical for water resource management and climate risk monitoring.This work provides a detailed,multi-scale evaluation of four major satellite precipitation products(CHIRPS,PERSIANN-CDR,IMERG-F v07,and GSMaP)over Isfahan province,Iran,over a 9-year period(2015-2023).The performance of these products was benchmarked against a dense network of 98 rain gauges using a suite of continuous and categorical statistical metrics,following a two-stage quality control protocol to remove outliers and false alarms.The results revealed that the performance of all products improves with temporal aggregation.At the daily level,GSMaP performed marginally better,although all products were linked with considerable uncertainty.At the monthly and annual levels,the GPM-era products(IMERG and GSMaP)clearly beat the other two,establishing themselves as dependable tools for long-term hydro-climatological studies.Error analysis revealed that topography is the dominant regulating factor,creating a systematic elevationdependent bias,largely characterized by underestimation from most products in high-elevation areas,though the PERSIANN-CDR product exhibited a contrasting overestimation tendency.Finally,the findings highlight the importance of implementing local,elevation-dependent calibration before deploying these products in hydrological modeling.
基金supported by Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012378)Natural Science Foundation of China(Nos.52471093,52274367)+3 种基金fund of the State Key Laboratory of Solidification Processing in NPU(No.2025‐QZ‐03)the Practice and Innovation Funds for Graduate Students of Northwestern Polytechnical University(No.PF2025041)Fundamental Research Projects of Science&Technology Innovation and development Plan in Yantai City(No.2024JCYJ099)project(No.ZR2024QE213)supported by Shandong Provincial Natural Science Foundation.
文摘The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of high‐content graphene reinforcements.This compromise becomes particularly severe in composites with high‐content graphene reinforcements,whose agglomeration leads to embrittlement and lubrication failure.Here,a flake powder-metallurgy strategy is developed to construct a self‐assembled lamellar structure in graphene/CoCrNi MPEA composites(Gr/MPEA_(AL)).This approach enables the uniform dispersion of a high graphene content(3.0 wt%),which is unattainable by conventional methods.The resulting composite exhibits a rare dual enhancement in performance:an order‐of‐magnitude improvement in wear resistance coupled with a low coefficient of friction.Intriguingly,the tribological behavior shows significant anisotropy,with optimal performance observed when sliding perpendicular to the lamellae.Through a multi‐scale methodology combining molecular dynamics simulations,finite element analysis,and systematic experiments,it is revealed that this exceptional performance stems from the synergy of high‐density deformation nanotwins,efficient strain delocalization,and abundant graphene‐derived lubricating sites.This work establishes a general paradigm for designing composite architectures that reconcile traditionally incompatible properties,offering broad implications for developing next‐generation structural materials with integrated mechanical robustness and surface functionality for safety‐critical applications.
基金funded by grants from the National Nature Science Foundation(Grant number:U23A20231)。
文摘Background This study was conducted to investigate the impact of varying degrees of heat stress on milk protein synthesis in dairy cows using comprehensive analyses of metabolomics and proteomics.Eighteen dairy cows were subjected to no heat stress(No-HS),mild heat stress(Mild-HS),and moderate heat stress(Mod-HS).Blood and milk samples were collected to determine the content and composition of amino acids(AA),and milk samples were used for metabolomic and proteomic analyses.Results Milk protein yield was significantly lower under Mild-HS and Mod-HS than No-HS(P<0.001).During Mild-HS,no significant difference was found in total AA concentration in both arterial(P=0.545)and venous blood(P=0.057),but arterial AA supply to the mammary gland significantly increased(P=0.045)when compared with No-HS.Under Mod-HS,the supply(P<0.001)and uptake(P=0.001)of total AA in the mammary gland decreased significantly,affecting the availability of precursors necessary for milk protein synthesis.Milk metabolomic analysis revealed that Mod-HS significantly impacted nucleotide metabolism,energy metabolism,and protein synthesis processes including translation,folding,and transport.Milk proteomic analysis showed significant downregulation of ribosomal and heat shock proteins which are crucial for protein synthesis and folding.Conclusions These findings suggest that heat stress disrupts AA utilization and energy metabolism in the mammary gland,leading to the reduced efficiency in milk protein synthesis and lowered milk protein yield.This study offers valuable insights into the metabolic and proteomic changes in dairy cows under heat stress,highlighting potential strategies to mitigate the adverse effects of heat stress on dairy production and milk quality.
文摘Description Journal of Integrative Agriculture(JIA),formerly Agricultural Sciences in China(ASC),founded in 2002,is sponsored by Chinese Academy of Agricultural Sciences(CAAS),co-sponsored by Chinese Association of Agricultural Science Societies(CAASS).JIA is a peer-reviewed and multi-disciplinary international journal and published monthly in English.JIA Editorial Board consists of 289 well-respected scholars of agricultural scientific fields.CAAS President,Academician Kongming Wu is the Chairman of the Board,and Academician Hualan Chen is the Editor-in-Chief.JIA has been available online at ScienceDirect since 2006 and is a leading academic journal in agricultural sciences in China.As released by JCR,the latest IF of the journal is 4.4.
基金supported by the confidential research grant No.a8317。
文摘To address the issues of frequent identity switches(IDs)and degraded identification accuracy in multi object tracking(MOT)under complex occlusion scenarios,this study proposes an occlusion-robust tracking framework based on face-pedestrian joint feature modeling.By constructing a joint tracking model centered on“intra-class independent tracking+cross-category dynamic binding”,designing a multi-modal matching metric with spatio-temporal and appearance constraints,and innovatively introducing a cross-category feature mutual verification mechanism and a dual matching strategy,this work effectively resolves performance degradation in traditional single-category tracking methods caused by short-term occlusion,cross-camera tracking,and crowded environments.Experiments on the Chokepoint_Face_Pedestrian_Track test set demonstrate that in complex scenes,the proposed method improves Face-Pedestrian Matching F1 area under the curve(F1 AUC)by approximately 4 to 43 percentage points compared to several traditional methods.The joint tracking model achieves overall performance metrics of IDF1:85.1825%and MOTA:86.5956%,representing improvements of 0.91 and 0.06 percentage points,respectively,over the baseline model.Ablation studies confirm the effectiveness of key modules such as the Intersection over Area(IoA)/Intersection over Union(IoU)joint metric and dynamic threshold adjustment,validating the significant role of the cross-category identity matching mechanism in enhancing tracking stability.Our_model shows a 16.7%frame per second(FPS)drop vs.fairness of detection and re-identification in multiple object tracking(FairMOT),with its cross-category binding module adding aboute 10%overhead,yet maintains near-real-time performance for essential face-pedestrian tracking at small resolutions.
基金supported by the National Natural Science Foundation of China(32371874,32401569)supported by Beijing Natural Science Foundation(6244053)。
文摘Monitoring waterbirds is vital for evaluating the ecological health of wetlands,and object detection offers an automated solution for identifying birds in monitoring imagery.However,conventional detection methods often overlook the multi-scale nature of bird targets,limiting their ability to capture rich contextual information across different scales.To address this,we propose a cross-dimensional attention network(CDA-Net)for bird detection that integrates spatial and channel information to improve species recognition.The proposed CDA-Net partitions feature maps into multiple channel wise sub-features.Spatial and channel attention are applied to each subfeature,and the resulting features are fused using the Hadamard product.The fused features are then forwarded to the detection head to generate the final detection results.This approach effectively captures and integrates information across spatial and channel dimensions.Experiments on our self-constructed Nanhai Wetland Waterbird Dataset and the public CUB-200-2011 dataset yield precision scores of 91.32%and 81.99%,respectively,outperforming existing methods.Our approach effectively handles scale variation in bird detection and provides a valuable tool for advancing automated wetland waterbird monitoring.
