Objective:Arrhythmia-induced cardiomyopathy(AIC)is a reversible dilated cardiomyopathy induced by rapid or irregular heartbeat.Acupuncture has a long history of use in the treatment of cardiac diseases,and Xinshu(BL15...Objective:Arrhythmia-induced cardiomyopathy(AIC)is a reversible dilated cardiomyopathy induced by rapid or irregular heartbeat.Acupuncture has a long history of use in the treatment of cardiac diseases,and Xinshu(BL15)is a key acupoint.However,the underlying mechanism of acupuncture at BL15 in the treatment of AIC has not yet been elucidated.Methods:AIC was induced in adult male Sprague-Dawley(SD)rats by continuous administration of acetylcholine(ACh)-CaCl2 and treatment with electroacupuncture(EA)at bilateral BL15.Echocardiography was used to evaluate cardiac function;the rotarod test for motor coordination and performance;hematoxylin and eosin(HE)staining for the morphology of ventricles;electrocardiogram for susceptibility,inducibility,and duration of atrial fibrillation(AF);and electrical and optical mapping in isolated rat hearts maintained by the Langendorff perfusion system for electrical conduction and intracellular handling,respectively.Reverse transcription quantitative polymerase chain reaction(RT-qPCR)and Western blotting were used to determine the levels of cardiac conduction and intracellular calcium-handling proteins in the ventricle.Results:The results showed that EA improved the ejection factor and morphological indices on echocardiography,restored motor coordination and performance,and alleviated ventricular dilation and AF onset.EA alleviates atrial conduction disorders,shortens APD80,and decreases calcium handling in rats with AIC.Cx43 was downregulated and CaMKII was upregulated,and both effects were reversed by EA treatment.Conclusion:Our study provides a novel AIC model with abnormal electrical propagation and calcium handling that can be protected by EA at BL15.This potential mechanism may be associated with the modulation of Cx43 and CaMKII expression.展开更多
On a sunny afternoon,Nelly Wahome mounted a smartphone on a tripod to film one of Mombasa’s tourist hotspots-Nyali Resort,a popular northern beach resort in Kenya.Wahome,25,shared the latest video clip via her TikTok...On a sunny afternoon,Nelly Wahome mounted a smartphone on a tripod to film one of Mombasa’s tourist hotspots-Nyali Resort,a popular northern beach resort in Kenya.Wahome,25,shared the latest video clip via her TikTok handle in a quest to enchant her followers with the day’s tourism scene along Nyali’s coastline.Within a few hours of uploading,her content attracted hundreds of views.展开更多
Visa-Free Trips Double Border inspection agencies across China handled 64.88 million cross-border trips by foreigners in 2024,up 82.9 percent from a year earlier.Among them,more than 20 million inbound trips by foreig...Visa-Free Trips Double Border inspection agencies across China handled 64.88 million cross-border trips by foreigners in 2024,up 82.9 percent from a year earlier.Among them,more than 20 million inbound trips by foreigners were made visa-free,a year-on-year increase of 112.3 percent,according to statistics released by the National Immigration Administration on 14 January.展开更多
The need to transport goods across countries and islands has resulted in a high demand for commercial vessels.Owing to such trends,shipyards must efficiently produce ships to reduce production costs.Layout and materia...The need to transport goods across countries and islands has resulted in a high demand for commercial vessels.Owing to such trends,shipyards must efficiently produce ships to reduce production costs.Layout and material flow are among the crucial aspects determining the efficiency of the production at a shipyard.This paper presents the initial design optimization of a shipyard layout using Nondominated Sorting Algorithm-Ⅱ(NSGA-Ⅱ)to find the optimal configuration of workstations in a shipyard layout.The proposed method focuses on simultaneously minimizing two material handling costs,namely work-based material handling and duration-based material handling.NSGA-Ⅱ determines the order of workstations in the shipyard layout.The semiflexible bay structure is then used in the workstation placement process from the sequence formed in NSGA-Ⅱ into a complete design.Considering that this study is a case of multiobjective optimization,the performance for both objectives at each iteration is presented in a 3D graph.Results indicate that after 500 iterations,the optimal configuration yields a work-based MHC of 163670.0 WBM-units and a duration-based MHC of 34750 DBM-units.Starting from a random solution,the efficiency of NSGA-Ⅱ demonstrates significant improvements,achieving a 50.19%reduction in work-based MHC and a 48.58%reduction in duration-based MHC.展开更多
Object detection in occluded environments remains a core challenge in computer vision(CV),especially in domains such as autonomous driving and robotics.While Convolutional Neural Network(CNN)-based twodimensional(2D)a...Object detection in occluded environments remains a core challenge in computer vision(CV),especially in domains such as autonomous driving and robotics.While Convolutional Neural Network(CNN)-based twodimensional(2D)and three-dimensional(3D)object detection methods havemade significant progress,they often fall short under severe occlusion due to depth ambiguities in 2D imagery and the high cost and deployment limitations of 3D sensors such as Light Detection and Ranging(LiDAR).This paper presents a comparative review of recent 2D and 3D detection models,focusing on their occlusion-handling capabilities and the impact of sensor modalities such as stereo vision,Time-of-Flight(ToF)cameras,and LiDAR.In this context,we introduce FuDensityNet,our multimodal occlusion-aware detection framework that combines Red-Green-Blue(RGB)images and LiDAR data to enhance detection performance.As a forward-looking direction,we propose a monocular depth-estimation extension to FuDensityNet,aimed at replacing expensive 3D sensors with a more scalable CNN-based pipeline.Although this enhancement is not experimentally evaluated in this manuscript,we describe its conceptual design and potential for future implementation.展开更多
Radiation detectors, such as survey meters, are essential for ensuring radiation safety in various sectors, including healthcare, industrial processing, emergency response, etc. However, regular calibration and proper...Radiation detectors, such as survey meters, are essential for ensuring radiation safety in various sectors, including healthcare, industrial processing, emergency response, etc. However, regular calibration and proper maintenance of survey meters are important in order to ascertain their accuracy and reliability. This study provides a comprehensive retrospective assessment of the calibration behaviour, durability, and fault trends of 160 survey meters, spanning ten different models. They were calibrated at the Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria over a decade (2012-2023) using an X-Ray Beam Irradiator Model X80-225K and Cs-137 irradiator (OB6) with a PTW reference spherical chamber traceable to the IAEA SSDL in Seibersdorf, Austria. The calibration stability of each model was evaluated, revealing that models like Instrument A and Instrument B demonstrated high reliability with calibration factors close to the ideal value of 1, while models like Instrument C exhibited higher variability, suggesting less consistent performance for dose rate monitoring. Fault analysis showed that the most common issues were related to the battery compartment, indicating a need for improved handling practices. Correlation analysis reveals no statistically significant correlation between calibration factor and age of survey meter across the analysed models. The study concludes that regular calibration, proper handling, and user training are crucial for maintaining the accuracy and longevity of radiation detectors.展开更多
This paper introduces an intelligent garbage-handling trolley model based on an STM32 single chip microcomputer as the control core.The device is driven by four independent motors to achieve automatic tracking,automat...This paper introduces an intelligent garbage-handling trolley model based on an STM32 single chip microcomputer as the control core.The device is driven by four independent motors to achieve automatic tracking,automatic obstacle avoidance,and fixed-point docking.Using external execution structure to realize the car without the use of a mechanical arm,complete garbage collection,storage,and uninstall function.On this basis,the type of garbage is marked by color,and the color recognition sensor is applied to realize the type recognition after garbage collection and put into the corresponding unloading point,to realize its intelligent classification function.It can automatically complete the established task autonomously.展开更多
Accurate reservoir permeability determination is crucial in hydrocarbon exploration and production.Conventional methods relying on empirical correlations and assumptions often result in high costs,time consumption,ina...Accurate reservoir permeability determination is crucial in hydrocarbon exploration and production.Conventional methods relying on empirical correlations and assumptions often result in high costs,time consumption,inaccuracies,and uncertainties.This study introduces a novel hybrid machine learning approach to predict the permeability of the Wangkwar formation in the Gunya oilfield,Northwestern Uganda.The group method of data handling with differential evolution(GMDH-DE)algorithm was used to predict permeability due to its capability to manage complex,nonlinear relationships between variables,reduced computation time,and parameter optimization through evolutionary algorithms.Using 1953 samples from Gunya-1 and Gunya-2 wells for training and 1563 samples from Gunya-3 for testing,the GMDH-DE outperformed the group method of data handling(GMDH)and random forest(RF)in predicting permeability with higher accuracy and lower computation time.The GMDH-DE achieved an R^(2)of 0.9985,RMSE of 3.157,MAE of 2.366,and ME of 0.001 during training,and for testing,the ME,MAE,RMSE,and R^(2)were 1.3508,12.503,21.3898,and 0.9534,respectively.Additionally,the GMDH-DE demonstrated a 41%reduction in processing time compared to GMDH and RF.The model was also used to predict the permeability of the Mita Gamma well in the Mandawa basin,Tanzania,which lacks core data.Shapley additive explanations(SHAP)analysis identified thermal neutron porosity(TNPH),effective porosity(PHIE),and spectral gamma-ray(SGR)as the most critical parameters in permeability prediction.Therefore,the GMDH-DE model offers a novel,efficient,and accurate approach for fast permeability prediction,enhancing hydrocarbon exploration and production.展开更多
Dear Editor,In this letter,a novel hierarchical fusion framework is proposed to address the imperfect data property in complex medical image analysis(MIA)scenes.In particular,by combining the strengths of convolutiona...Dear Editor,In this letter,a novel hierarchical fusion framework is proposed to address the imperfect data property in complex medical image analysis(MIA)scenes.In particular,by combining the strengths of convolutional neural networks(CNNs)and transformers,the enhanced feature extraction,spatial modeling,and sequential context learning are realized to provide comprehensive insights on the complex data patterns.Integration of information in different level is enabled via a multi-attention fusion mechanism,and the tensor decomposition methods are adopted so that compact and distinctive representation of the underlying and high-dimensional medical image features can be accomplished[1].It is shown from the evaluation results that the proposed framework is competitive and superior as compared with some other advanced algorithms,which effectively handles the imperfect property of inter-class similarity and intra-class differences in diseases,and meanwhile,the model complexity is reduced within an acceptable level,which benefits the deployment in clinic practice.MIA has assumed a pivotal role in numerous critical clinical scenarios,where sophisticated image analysis techniques have proven instrumental in augmenting medical decision-making,facilitating individualized therapeutic interventions,and enhancing patient prognostication[2]−[4].展开更多
Hydraulic manipulators are usually applied in heavy-load and harsh operation tasks.However,when faced with a complex operation,the traditional proportional-integral-derivative(PID)control may not meet requirements for...Hydraulic manipulators are usually applied in heavy-load and harsh operation tasks.However,when faced with a complex operation,the traditional proportional-integral-derivative(PID)control may not meet requirements for high control performance.Model-based full-state-feedback control is an effective alternative,but the states of a hydraulic manipulator are not always available and reliable in practical applications,particularly the joint angular velocity measurement.Considering that it is not suitable to obtain the velocity signal directly from differentiating of position measurement,the low-pass filtering is commonly used,but it will definitely restrict the closed-loop bandwidth of the whole system.To avoid this problem and realize better control performance,this paper proposes a novel observerbased adaptive robust controller(obARC)for a multi-joint hydraulic manipulator subjected to both parametric uncertainties and the lack of accurate velocity measurement.Specifically,a nonlinear adaptive observer is first designed to handle the lack of velocity measurement with the consideration of parametric uncertainties.Then,the adaptive robust control is developed to compensate for the dynamic uncertainties,and the close-loop system robust stability is theoretically proved under the observation and control errors.Finally,comparative experiments are carried out to show that the designed controller can achieve a performance improvement over the traditional methods,specifically yielding better control accuracy owing to the closed-loop bandwidth breakthrough,which is limited by low-pass filtering in fullstate-feedback control.展开更多
Machine learning has been extensively applied in behavioural and social computing,encompassing a spectrum of applications such as social network analysis,click stream analysis,recommendation of points of interest,and ...Machine learning has been extensively applied in behavioural and social computing,encompassing a spectrum of applications such as social network analysis,click stream analysis,recommendation of points of interest,and sentiment analysis.The datasets pertinent to these applications are inherently linked to human behaviour and societal dynamics,posing a risk of disclosing personal or sensitive information if mishandled or subjected to attacks.展开更多
At present,air handling units are usually used indoors to improve the indoor environment quality.However,while introducing fresh air to improve air quality,air velocity has a certain impact on the occupants’thermal c...At present,air handling units are usually used indoors to improve the indoor environment quality.However,while introducing fresh air to improve air quality,air velocity has a certain impact on the occupants’thermal comfort.Therefore,it is necessary to explore the optimization of air-fluid-body interaction dynamics.In this study,the indoor air flow was changed by changing the opening and closing degree of the blower,and the thermal manikin is introduced to objectively evaluate the human thermal comfort under different air velocities.The main experimental results show that the air change rate increases with the increase of the opening and closing degree of the blower considering an ACH(air changes per hour)range between 3.8 and 10.For a better prediction,a linear correlation with a coefficient of 0.995 is proposed.As the blower’s opening is adjusted to 20%,25%,30%,35%,and 40%,the air velocity sensor positioned directly beneath the air inlet records average velocities of 0.19,0.20,0.21,0.28,and 0.34 m/s over four hours,respectively.Observations on thermal comfort and the average sensation experienced by individuals indicate an initial increase followed by a decline when the blower’s operation begins,with optimal conditions achieved at a 35%opening.These findings offer valuable insights for future indoor air ventilation and heat transfer design strategies.展开更多
Introduction: Musculoskeletal disorders are disorders of the musculoskeletal system related to work. The objective of this study was to musculoskeletal disorders among SOGEAC handlers. Methodology: This was a descript...Introduction: Musculoskeletal disorders are disorders of the musculoskeletal system related to work. The objective of this study was to musculoskeletal disorders among SOGEAC handlers. Methodology: This was a descriptive and analytic cross-sectional study over 6 months from November 2021 to April 2022. Results: We collected 110 handlers during the study. All of our population had postural constraints and were men. The average age of workers was 39.2 years. 93 handlers or 84.5% did manual handling, and 79% or 71.8% were baggage handlers. Regarding training, 88.2% or 97 handlers were trained, and 89.1% did alternating work. The standing posture was the most adopted with 89.1% followed by the kneeling position with 66.4%. 89.1% carried weights at work. 80 handlers or 73% had developed musculoskeletal disorders and the lumbar seat was found at 70%. The analysis of factors that may influence the occurrence of musculoskeletal disorders did not find any statistically significant relation. Conclusion: Our study shows that musculoskeletal disorders are an occupational health problem and recommends better compliance with occupational safety and health instructions.展开更多
基金supported by the National Key R&D Program of China(2022YFC3500405,2019YFC1712105)The National Science Foundation of China(82374075)+1 种基金The National Comprehensive Traditional Chinese Medicine Reform Demonstration Zone Science and Technology Collaborative Development Project(GZY-KJS-SD-2024-046)Taishan Scholar Youth Project of Shandong Province(tsqn202306188).
文摘Objective:Arrhythmia-induced cardiomyopathy(AIC)is a reversible dilated cardiomyopathy induced by rapid or irregular heartbeat.Acupuncture has a long history of use in the treatment of cardiac diseases,and Xinshu(BL15)is a key acupoint.However,the underlying mechanism of acupuncture at BL15 in the treatment of AIC has not yet been elucidated.Methods:AIC was induced in adult male Sprague-Dawley(SD)rats by continuous administration of acetylcholine(ACh)-CaCl2 and treatment with electroacupuncture(EA)at bilateral BL15.Echocardiography was used to evaluate cardiac function;the rotarod test for motor coordination and performance;hematoxylin and eosin(HE)staining for the morphology of ventricles;electrocardiogram for susceptibility,inducibility,and duration of atrial fibrillation(AF);and electrical and optical mapping in isolated rat hearts maintained by the Langendorff perfusion system for electrical conduction and intracellular handling,respectively.Reverse transcription quantitative polymerase chain reaction(RT-qPCR)and Western blotting were used to determine the levels of cardiac conduction and intracellular calcium-handling proteins in the ventricle.Results:The results showed that EA improved the ejection factor and morphological indices on echocardiography,restored motor coordination and performance,and alleviated ventricular dilation and AF onset.EA alleviates atrial conduction disorders,shortens APD80,and decreases calcium handling in rats with AIC.Cx43 was downregulated and CaMKII was upregulated,and both effects were reversed by EA treatment.Conclusion:Our study provides a novel AIC model with abnormal electrical propagation and calcium handling that can be protected by EA at BL15.This potential mechanism may be associated with the modulation of Cx43 and CaMKII expression.
文摘On a sunny afternoon,Nelly Wahome mounted a smartphone on a tripod to film one of Mombasa’s tourist hotspots-Nyali Resort,a popular northern beach resort in Kenya.Wahome,25,shared the latest video clip via her TikTok handle in a quest to enchant her followers with the day’s tourism scene along Nyali’s coastline.Within a few hours of uploading,her content attracted hundreds of views.
文摘Visa-Free Trips Double Border inspection agencies across China handled 64.88 million cross-border trips by foreigners in 2024,up 82.9 percent from a year earlier.Among them,more than 20 million inbound trips by foreigners were made visa-free,a year-on-year increase of 112.3 percent,according to statistics released by the National Immigration Administration on 14 January.
基金Supported by Direktorat Riset dan Pengembangan(Directorate of Research and Development)Universitas Indonesia(NKB-690/UN2.RST/HKP.05.00/2022).
文摘The need to transport goods across countries and islands has resulted in a high demand for commercial vessels.Owing to such trends,shipyards must efficiently produce ships to reduce production costs.Layout and material flow are among the crucial aspects determining the efficiency of the production at a shipyard.This paper presents the initial design optimization of a shipyard layout using Nondominated Sorting Algorithm-Ⅱ(NSGA-Ⅱ)to find the optimal configuration of workstations in a shipyard layout.The proposed method focuses on simultaneously minimizing two material handling costs,namely work-based material handling and duration-based material handling.NSGA-Ⅱ determines the order of workstations in the shipyard layout.The semiflexible bay structure is then used in the workstation placement process from the sequence formed in NSGA-Ⅱ into a complete design.Considering that this study is a case of multiobjective optimization,the performance for both objectives at each iteration is presented in a 3D graph.Results indicate that after 500 iterations,the optimal configuration yields a work-based MHC of 163670.0 WBM-units and a duration-based MHC of 34750 DBM-units.Starting from a random solution,the efficiency of NSGA-Ⅱ demonstrates significant improvements,achieving a 50.19%reduction in work-based MHC and a 48.58%reduction in duration-based MHC.
文摘Object detection in occluded environments remains a core challenge in computer vision(CV),especially in domains such as autonomous driving and robotics.While Convolutional Neural Network(CNN)-based twodimensional(2D)and three-dimensional(3D)object detection methods havemade significant progress,they often fall short under severe occlusion due to depth ambiguities in 2D imagery and the high cost and deployment limitations of 3D sensors such as Light Detection and Ranging(LiDAR).This paper presents a comparative review of recent 2D and 3D detection models,focusing on their occlusion-handling capabilities and the impact of sensor modalities such as stereo vision,Time-of-Flight(ToF)cameras,and LiDAR.In this context,we introduce FuDensityNet,our multimodal occlusion-aware detection framework that combines Red-Green-Blue(RGB)images and LiDAR data to enhance detection performance.As a forward-looking direction,we propose a monocular depth-estimation extension to FuDensityNet,aimed at replacing expensive 3D sensors with a more scalable CNN-based pipeline.Although this enhancement is not experimentally evaluated in this manuscript,we describe its conceptual design and potential for future implementation.
文摘Radiation detectors, such as survey meters, are essential for ensuring radiation safety in various sectors, including healthcare, industrial processing, emergency response, etc. However, regular calibration and proper maintenance of survey meters are important in order to ascertain their accuracy and reliability. This study provides a comprehensive retrospective assessment of the calibration behaviour, durability, and fault trends of 160 survey meters, spanning ten different models. They were calibrated at the Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria over a decade (2012-2023) using an X-Ray Beam Irradiator Model X80-225K and Cs-137 irradiator (OB6) with a PTW reference spherical chamber traceable to the IAEA SSDL in Seibersdorf, Austria. The calibration stability of each model was evaluated, revealing that models like Instrument A and Instrument B demonstrated high reliability with calibration factors close to the ideal value of 1, while models like Instrument C exhibited higher variability, suggesting less consistent performance for dose rate monitoring. Fault analysis showed that the most common issues were related to the battery compartment, indicating a need for improved handling practices. Correlation analysis reveals no statistically significant correlation between calibration factor and age of survey meter across the analysed models. The study concludes that regular calibration, proper handling, and user training are crucial for maintaining the accuracy and longevity of radiation detectors.
文摘This paper introduces an intelligent garbage-handling trolley model based on an STM32 single chip microcomputer as the control core.The device is driven by four independent motors to achieve automatic tracking,automatic obstacle avoidance,and fixed-point docking.Using external execution structure to realize the car without the use of a mechanical arm,complete garbage collection,storage,and uninstall function.On this basis,the type of garbage is marked by color,and the color recognition sensor is applied to realize the type recognition after garbage collection and put into the corresponding unloading point,to realize its intelligent classification function.It can automatically complete the established task autonomously.
基金supported by the Major National Science and Technology Programs in the“Thirteenth Five-Year”Plan period(Grant No.2017ZX05032-002-004)the Innovation Team Funding of Natural Science Foundation of Hubei Province,China(Grant No.2021CFA031)the Chinese Scholarship Council(CSC)and Silk Road Institute for their support in terms of stipend.
文摘Accurate reservoir permeability determination is crucial in hydrocarbon exploration and production.Conventional methods relying on empirical correlations and assumptions often result in high costs,time consumption,inaccuracies,and uncertainties.This study introduces a novel hybrid machine learning approach to predict the permeability of the Wangkwar formation in the Gunya oilfield,Northwestern Uganda.The group method of data handling with differential evolution(GMDH-DE)algorithm was used to predict permeability due to its capability to manage complex,nonlinear relationships between variables,reduced computation time,and parameter optimization through evolutionary algorithms.Using 1953 samples from Gunya-1 and Gunya-2 wells for training and 1563 samples from Gunya-3 for testing,the GMDH-DE outperformed the group method of data handling(GMDH)and random forest(RF)in predicting permeability with higher accuracy and lower computation time.The GMDH-DE achieved an R^(2)of 0.9985,RMSE of 3.157,MAE of 2.366,and ME of 0.001 during training,and for testing,the ME,MAE,RMSE,and R^(2)were 1.3508,12.503,21.3898,and 0.9534,respectively.Additionally,the GMDH-DE demonstrated a 41%reduction in processing time compared to GMDH and RF.The model was also used to predict the permeability of the Mita Gamma well in the Mandawa basin,Tanzania,which lacks core data.Shapley additive explanations(SHAP)analysis identified thermal neutron porosity(TNPH),effective porosity(PHIE),and spectral gamma-ray(SGR)as the most critical parameters in permeability prediction.Therefore,the GMDH-DE model offers a novel,efficient,and accurate approach for fast permeability prediction,enhancing hydrocarbon exploration and production.
基金supported in part by the National Natural Science Foundation of China(62073271)the Fundamental Research Funds for the Central Universities of China(20720220076)the Natural Science Foundation for Distinguished Young Scholars of the Fujian Province of China(2023 J06010).
文摘Dear Editor,In this letter,a novel hierarchical fusion framework is proposed to address the imperfect data property in complex medical image analysis(MIA)scenes.In particular,by combining the strengths of convolutional neural networks(CNNs)and transformers,the enhanced feature extraction,spatial modeling,and sequential context learning are realized to provide comprehensive insights on the complex data patterns.Integration of information in different level is enabled via a multi-attention fusion mechanism,and the tensor decomposition methods are adopted so that compact and distinctive representation of the underlying and high-dimensional medical image features can be accomplished[1].It is shown from the evaluation results that the proposed framework is competitive and superior as compared with some other advanced algorithms,which effectively handles the imperfect property of inter-class similarity and intra-class differences in diseases,and meanwhile,the model complexity is reduced within an acceptable level,which benefits the deployment in clinic practice.MIA has assumed a pivotal role in numerous critical clinical scenarios,where sophisticated image analysis techniques have proven instrumental in augmenting medical decision-making,facilitating individualized therapeutic interventions,and enhancing patient prognostication[2]−[4].
基金supported by the National Natural Science Foundation of China(52075476,52105065,92048302)Zhejiang Provincial Natural Science Foundation of China(LR23E050001)the Science and Technology Program of Hebei(E2021210011)。
文摘Hydraulic manipulators are usually applied in heavy-load and harsh operation tasks.However,when faced with a complex operation,the traditional proportional-integral-derivative(PID)control may not meet requirements for high control performance.Model-based full-state-feedback control is an effective alternative,but the states of a hydraulic manipulator are not always available and reliable in practical applications,particularly the joint angular velocity measurement.Considering that it is not suitable to obtain the velocity signal directly from differentiating of position measurement,the low-pass filtering is commonly used,but it will definitely restrict the closed-loop bandwidth of the whole system.To avoid this problem and realize better control performance,this paper proposes a novel observerbased adaptive robust controller(obARC)for a multi-joint hydraulic manipulator subjected to both parametric uncertainties and the lack of accurate velocity measurement.Specifically,a nonlinear adaptive observer is first designed to handle the lack of velocity measurement with the consideration of parametric uncertainties.Then,the adaptive robust control is developed to compensate for the dynamic uncertainties,and the close-loop system robust stability is theoretically proved under the observation and control errors.Finally,comparative experiments are carried out to show that the designed controller can achieve a performance improvement over the traditional methods,specifically yielding better control accuracy owing to the closed-loop bandwidth breakthrough,which is limited by low-pass filtering in fullstate-feedback control.
文摘Machine learning has been extensively applied in behavioural and social computing,encompassing a spectrum of applications such as social network analysis,click stream analysis,recommendation of points of interest,and sentiment analysis.The datasets pertinent to these applications are inherently linked to human behaviour and societal dynamics,posing a risk of disclosing personal or sensitive information if mishandled or subjected to attacks.
基金supported by the China Scholarship Council(Grant Number 202208120025).
文摘At present,air handling units are usually used indoors to improve the indoor environment quality.However,while introducing fresh air to improve air quality,air velocity has a certain impact on the occupants’thermal comfort.Therefore,it is necessary to explore the optimization of air-fluid-body interaction dynamics.In this study,the indoor air flow was changed by changing the opening and closing degree of the blower,and the thermal manikin is introduced to objectively evaluate the human thermal comfort under different air velocities.The main experimental results show that the air change rate increases with the increase of the opening and closing degree of the blower considering an ACH(air changes per hour)range between 3.8 and 10.For a better prediction,a linear correlation with a coefficient of 0.995 is proposed.As the blower’s opening is adjusted to 20%,25%,30%,35%,and 40%,the air velocity sensor positioned directly beneath the air inlet records average velocities of 0.19,0.20,0.21,0.28,and 0.34 m/s over four hours,respectively.Observations on thermal comfort and the average sensation experienced by individuals indicate an initial increase followed by a decline when the blower’s operation begins,with optimal conditions achieved at a 35%opening.These findings offer valuable insights for future indoor air ventilation and heat transfer design strategies.
文摘Introduction: Musculoskeletal disorders are disorders of the musculoskeletal system related to work. The objective of this study was to musculoskeletal disorders among SOGEAC handlers. Methodology: This was a descriptive and analytic cross-sectional study over 6 months from November 2021 to April 2022. Results: We collected 110 handlers during the study. All of our population had postural constraints and were men. The average age of workers was 39.2 years. 93 handlers or 84.5% did manual handling, and 79% or 71.8% were baggage handlers. Regarding training, 88.2% or 97 handlers were trained, and 89.1% did alternating work. The standing posture was the most adopted with 89.1% followed by the kneeling position with 66.4%. 89.1% carried weights at work. 80 handlers or 73% had developed musculoskeletal disorders and the lumbar seat was found at 70%. The analysis of factors that may influence the occurrence of musculoskeletal disorders did not find any statistically significant relation. Conclusion: Our study shows that musculoskeletal disorders are an occupational health problem and recommends better compliance with occupational safety and health instructions.
