In the context of security systems,adequate signal coverage is paramount for the communication between security personnel and the accurate positioning of personnel.Most studies focus on optimizing base station deploym...In the context of security systems,adequate signal coverage is paramount for the communication between security personnel and the accurate positioning of personnel.Most studies focus on optimizing base station deployment under the assumption of static obstacles,aiming to maximize the perception coverage of wireless RF(Radio Frequency)signals and reduce positioning blind spots.However,in practical security systems,obstacles are subject to change,necessitating the consideration of base station deployment in dynamic environments.Nevertheless,research in this area still needs to be conducted.This paper proposes a Dynamic Indoor Environment Beacon Deployment Algorithm(DIE-BDA)to address this problem.This algorithm considers the dynamic alterations in obstacle locations within the designated area.It determines the requisite number of base stations,the requisite time,and the area’s practical and overall signal coverage rates.The experimental results demonstrate that the algorithm can calculate the deployment strategy in 0.12 s following a change in obstacle positions.Experimental results show that the algorithm in this paper requires 0.12 s to compute the deployment strategy after the positions of obstacles change.With 13 base stations,it achieves an effective coverage rate of 93.5%and an overall coverage rate of 97.75%.The algorithm can rapidly compute a revised deployment strategy in response to changes in obstacle positions within security systems,thereby ensuring the efficacy of signal coverage.展开更多
The flow field architecture of the proton exchange membrane fuel cell(PEMFC)cathode critically determines its performance.To enhance PEMFC operation through structural optimization,trapezoidal obstacles were implement...The flow field architecture of the proton exchange membrane fuel cell(PEMFC)cathode critically determines its performance.To enhance PEMFC operation through structural optimization,trapezoidal obstacles were implemented in the cathode flow channels.The height dependence of these obstacles was systematically investigated,revealing that a 0.7 mm obstacle height enhanced mass transfer from channels to the gas diffusion layer(GDL)compared to conventional triple-serpentine designs.This configuration achieved a 12.08%increase in limiting current density alongside improved water management.Subsequent studies on obstacle distribution density identified 75%density as optimal,delivering maximum net power density with 10.6%lower pressure drop than full-density arrangements.展开更多
Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate obstacles.After spinal cord injury,stepping over an obstacle becomes challenging.Stepping over an obstacle requires senso...Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate obstacles.After spinal cord injury,stepping over an obstacle becomes challenging.Stepping over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor cortex.Sensory information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain balance.After spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an obstacle.Therefore,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.展开更多
Intelligent robots are increasingly being deployed across industries ranging from manufacturing to household applications and outdoor exploration.Their autonomous obstacle avoidance capabilities in complex environment...Intelligent robots are increasingly being deployed across industries ranging from manufacturing to household applications and outdoor exploration.Their autonomous obstacle avoidance capabilities in complex environments have become a critical factor determining operational stability.Multimodal perception technology,which integrates visual,auditory,tactile,and LiDAR data,provides robots with comprehensive environmental awareness.By establishing efficient autonomous obstacle avoidance decision-making mechanisms based on this information,the system’s adaptability to challenging scenarios can be significantly enhanced.This study investigates the integration of multimodal perception with autonomous obstacle avoidance decision-making,analyzing the acquisition and processing of perceptual information,core modules and logic of decision-making mechanisms,and proposing optimization strategies for specific scenarios.The research aims to provide theoretical references for advancing autonomous obstacle avoidance technology in intelligent robots,enabling safer and more flexible movement in diverse environments.展开更多
Autonomous trucks have the potential to enhance both safety and convenience in intelligent transportation.However,their maximum speed and ability to navigate a variety of driving conditions,particularly uneven roads,a...Autonomous trucks have the potential to enhance both safety and convenience in intelligent transportation.However,their maximum speed and ability to navigate a variety of driving conditions,particularly uneven roads,are limited by a high center of gravity,which increases the risk of rollover.Road bulges,sinkholes,and unexpected debris all present additional challenges for autonomous trucks’operational design,which current perception and decisionmaking algorithms often overlook.To mitigate rollover risks and improve adaptability to damaged roads,this paper presents a novel Road Obstacle-Involved Trajectory Planner(ROITP).The planner categorizes road obstacles using a learning-based algorithm.A discrete optimization algorithm selects a multi-objective optimal trajectory while taking into account constraints and objective functions derived from truck dynamics.Validation across various scenarios on a hardware-in-loop platform demonstrates that the proposed planner is effective and feasible for real-time implementation.展开更多
[Objectives]This study was conducted to comprehensively understand the changes in gene expression of plants under environmental stress during different growth and development stages.[Methods]The effects of continuous ...[Objectives]This study was conducted to comprehensively understand the changes in gene expression of plants under environmental stress during different growth and development stages.[Methods]The effects of continuous cropping on the roots and leaves of Polygonatum sibiricum were investigated using transcriptome sequencing.Normally-grown first crop P.sibiricum was used as the control group,while continuous cropping plants served as the treatment group.Transcriptomic differences in roots and leaves under different conditions were compared.[Results]The leaf materials of first crop and continuous cropping P.sibiricum(CCLZ vs FCLZ)showed 21916 differentially expressed genes(DEGs),while the root materials of first crop and continuous cropping P.sibiricum(CCRZ vs FCRZ)exhibited 12726 DEGs(the lowest DEG count)(12726).Among them,1896 DEGs were common.GO enrichment analysis revealed that DEGs were mainly enriched in metabolism,cell wall degradation,and pathogen defense.KEGG enrichment analysis indicated that DEGs in CCLZ vs FCLZ and CCRZ vs FCRZ primarily affected hormone signal transduction and pathogen interaction pathways.[Conclusions]This study preliminarily elucidate the regulatory mechanisms in the roots and leaves of continuous cropping P.sibiricum at the molecular level,providing reference for research on its adaptation to continuous cropping.展开更多
In recent years, the uncontrollable risks of urban production-living-ecological(PLE)space have increased sharply, making resilience enhancement essential for sustainable urban development. Based on the social-ecologic...In recent years, the uncontrollable risks of urban production-living-ecological(PLE)space have increased sharply, making resilience enhancement essential for sustainable urban development. Based on the social-ecological system(SES) theory, this study constructs an assessment framework for urban PLE space resilience by analyzing its inherent characteristics. The central urban area of Ganzhou city is taken as a case study to evaluate urban PLE space resilience and diagnose its obstacles. The results are as follows: The PLE space resilience in the central urban area of Ganzhou exhibits gradations and substantial spatial differentiation. The ecological space resilience in the study area was the highest, followed by that of production space, while living space resilience was the lowest. The primary factors influencing PLE space resilience are concentrated in the dimensions of robustness and adaptability. In particular, the robustness of the PLE space is relatively low. Based on these results, targeted spatial resilience governance strategies for the PLE space have been proposed. These strategies serve as theoretical and technical references for the study area. By adopting the PLE space perspective, this paper enriches resilience research and provide theoretical support for sustainable urban development.展开更多
A three-dimensional path-planning approach has been developed to coordinate multiple fixed-wing unmanned aerial vehicles(UAVs)while avoiding collisions.The hierarchical path-planning architecture that divides the path...A three-dimensional path-planning approach has been developed to coordinate multiple fixed-wing unmanned aerial vehicles(UAVs)while avoiding collisions.The hierarchical path-planning architecture that divides the path-planning process into two layers is proposed by designing the velocityobstacle strategy for satisfying timeliness and effectiveness.The upper-level layer focuses on creating an efficient Dubins initial path considering the dynamic constraints of the fixed wing.Subsequently,the lower-level layer detects potential collisions and adjusts its flight paths to avoid collisions by using the threedimensional velocity obstacle method,which describes the maneuvering space of collision avoidance as the intersection space of half space.To further handle the dynamic and collisionavoidance constraints,a priority mechanism is designed to ensure that the adjusted path is still feasible for fixed-wing UAVs.Simulation experiments demonstrate the effectiveness of the proposed method.展开更多
Under the new development pattern,promoting the balanced development of the regional life service level is the key to attaining the goal of meeting people’s need for an improved life.This study constructed an index s...Under the new development pattern,promoting the balanced development of the regional life service level is the key to attaining the goal of meeting people’s need for an improved life.This study constructed an index system with six dimensions,namely,economic base,innovation drive,living environment,transportation,public services and life security,and explored the balanced characteristics and obstacles of the life service level in the Yangtze River Delta,China in 2020 using the Gini coefficient,the standard deviation ellipse,the global spatial autocorrelation,the equilibrium entropy and the obstacle degree model.Results show that:1)the current overall level of life services in the Yangtze River Delta is in relative equilibrium,and the Gini coefficient of three dimensions,namely,economic base,innovation drive and life security,is relatively low and on the verge of imbalance.2)The spatial pattern of the six dimensions of the overall level of the life service is oriented toward the‘southeast-northwest’direction with significant spatial differentiation and spatial agglomeration.3)At present,most of the cities have a comparative advantage in the coordination of their life services,and the potential of their life service system shows room for further improvement in the future.4)Currently,the quality of economic development,talent concentration,innovation inputs,innovation outputs,basic education,health care,cultural sharing,the living standards of the urban and rural residents and the construction of a transportation system are the main factors constraining the improvement of the level of life services in the Yangtze River Delta.This study attempts to research on the evaluation and measurement of regional life service level in the new era,and provides a reference for the promotion of regional coordination and sustainable development.展开更多
Despite its immense potential,the application of digital twin technology in real industrial scenarios still faces numerous challenges.This study focuses on industrial assembly lines in sectors such as microelectronics...Despite its immense potential,the application of digital twin technology in real industrial scenarios still faces numerous challenges.This study focuses on industrial assembly lines in sectors such as microelectronics,pharmaceuticals,and food packaging,where precision and speed are paramount,applying digital twin technology to the robotic assembly process.The innovation of this research lies in the development of a digital twin architecture and system for Delta robots that is suitable for real industrial environments.Based on this system,a deep reinforcement learning algorithm for obstacle avoidance path planning in Delta robots has been developed,significantly enhancing learning efficiency through an improved intermediate reward mechanism.Experiments on communication and interaction between the digital twin system and the physical robot validate the effectiveness of this method.The system not only enhances the integration of digital twin technology,deep reinforcement learning and robotics,offering an efficient solution for path planning and target grasping inDelta robots,but also underscores the transformative potential of digital twin technology in intelligent manufacturing,with extensive applicability across diverse industrial domains.展开更多
Rural resilience,a core capability for addressing systemic risks and enabling sustainable development,is increasingly vital to promoting urban-rural integrated development and rural revitalization strategies.However,c...Rural resilience,a core capability for addressing systemic risks and enabling sustainable development,is increasingly vital to promoting urban-rural integrated development and rural revitalization strategies.However,current research lacks exploration of the collaborative mechanisms between rural economic resilience(RER)and rural social resilience(RSR)in ecologically vulnerable areas.Based on the practical context of rural sustainable development in such regions,this study investigates the interaction between RER and RSR from a resilience coordination perspective.In this paper,a rural resilience evaluation framework for collaborative development of economic and social resilience was established.By employing the coupling coordination degree model,obstacle degree model,and equilibrium entropy model,this paper examines the synergies,constraints,and potential of rural resilience subsystems in Jinchang City,Gansu Province,China,in 2020.The results reveal that:1)RER contributes to RSR by stabilizing the economy,enhancing community adaptability,and driving modernization.In turn,RSR strengthens RER by mitigating instability,building social capital,and fostering confidence—together forming a mutually reinforcing coupling mechanism.2)The rural economic and social resilience level in Jinchang City remains generally low with spatially clustered patterns,while the coupling coordination degree is at an intermediate level overall,with 62.59%of villages exhibiting unbalanced development between rural economic and social resilience.3)RER and RSR demonstrate synergistic degradation in ecologically vulnerable areas,where low-level rural economic and social resilience induce integrated systemic deterioration.4)Considering the unbalanced development of rural economic and social resilience in ecologically fragile areas,differentiated coordination pathways are proposed for three village typologies:RER-lagging villages,RSR-lagging villages,and villages where RER and RSR develop synchronously but lack effective coordination.These findings offer spatial governance strategies and practical guidance for enhancing rural resilience and advancing sustainable development in ecologically vulnerable regions.展开更多
Introduction: Vaccination faces several obstacles in the fight against COVID-19, yet it has been identified as one of the most effective means of preventing new epidemics of COVID-19. The aim was to contribute to impr...Introduction: Vaccination faces several obstacles in the fight against COVID-19, yet it has been identified as one of the most effective means of preventing new epidemics of COVID-19. The aim was to contribute to improving vaccination coverage against COVID-19 in the Kindu health zone. Method: We conducted a cross-sectional descriptive study with an analytical focus, using a questionnaire that enabled us to carry out a survey from October 03 to 30, 2022. Our target study population was residents of the Kindu health zone. A total of 420 subjects participated in our study, including 42 per site. Results: The study revealed a low proportion of vaccinated subjects (38.3%) and a high proportion of non-vaccinated subjects (61.70%). Non-belief in the efficacy of vaccines (p = 0.001), infodemia (p = 0.001) and respect for ethnic norms (p = 0.001) were identified as perceived barriers to vaccination. Fear of being branded with the “666” beast badge (p = 0.004) as the perceived severity. Respondents’ perceptions of mass vaccination against COVID-19 are mixed, and their opinions and expectations of COVID-19 vaccination in the town of Kindu are divided. Conclusion: In order to increase the proportion of people vaccinated against COVID-19, it is suggested here to increase the population’s ability to detect false information through a well-structured communication and health education program.展开更多
Focusing on obstacle avoidance in three-dimensional space for unmanned aerial vehicle(UAV), the direct obstacle avoidance method in dynamic space based on three-dimensional velocity obstacle spherical cap is proposed,...Focusing on obstacle avoidance in three-dimensional space for unmanned aerial vehicle(UAV), the direct obstacle avoidance method in dynamic space based on three-dimensional velocity obstacle spherical cap is proposed, which quantifies the influence of threatening obstacles through velocity obstacle spherical cap parameters. In addition, the obstacle avoidance schemes of any point on the critical curve during the multi-obstacles avoidance are given. Through prediction, the insertion point for the obstacle avoidance can be obtained and the flight path can be replanned. Taking the Pythagorean Hodograph(PH) curve trajectory re-planning as an example, the three-dimensional direct obstacle avoidance method in dynamic space is tested. Simulation results show that the proposed method can realize the online obstacle avoidance trajectory re-planning, which increases the flexibility of obstacle avoidance greatly.展开更多
First at all, it introduced the concept and the damages of continuous cropping obstacle. Then, it analyzed the causes of continuous cropping obstacles for Atractylodes macrocephala Koidz. In the end, in order to provi...First at all, it introduced the concept and the damages of continuous cropping obstacle. Then, it analyzed the causes of continuous cropping obstacles for Atractylodes macrocephala Koidz. In the end, in order to provide guidance for pro- moting sustainable development of Atractylodes macrocephala Koidz industry in Pingjiang County, it put forward some control methods for eliminating continuous cropping obstacles of Atractylodes macrocephala Koidz, including breeding varieties with high resistance; applying rotation cropping and intercropping reasonable; rational fertilization and soil disinfection; introducing antagonistic bacterial and eliminating au- tointoxication.展开更多
The detection of obstacles in a dynamic environment is a hot and difficult problem.A method of autonomously detecting obstacles based on laser radar is proposed as a safety auxiliary structure of tram.The nearest neig...The detection of obstacles in a dynamic environment is a hot and difficult problem.A method of autonomously detecting obstacles based on laser radar is proposed as a safety auxiliary structure of tram.The nearest neighbor method is used for spatial obstacles clustering from laser radar data.By analyzing the characteristics of obstacles,the types of obstacles are determined by time correlation.Experiments were carried out on the developed unmanned aerial vehicle(UAV),and the experimental results verify the effectiveness of the proposed method.展开更多
Monocular vision-based navigation is a considerable ability for a home mobile robot. However, due to diverse disturbances, helping robots avoid obstacles, especially nonManhattan obstacles, remains a big challenge. In...Monocular vision-based navigation is a considerable ability for a home mobile robot. However, due to diverse disturbances, helping robots avoid obstacles, especially nonManhattan obstacles, remains a big challenge. In indoor environments, there are many spatial right-corners that are projected into two dimensional projections with special geometric configurations. These projections, which consist of three lines,might enable us to estimate their position and orientation in 3 D scenes. In this paper, we present a method for home robots to avoid non-Manhattan obstacles in indoor environments from a monocular camera. The approach first detects non-Manhattan obstacles. Through analyzing geometric features and constraints,it is possible to estimate posture differences between orientation of the robot and non-Manhattan obstacles. Finally according to the convergence of posture differences, the robot can adjust its orientation to keep pace with the pose of detected non-Manhattan obstacles, making it possible avoid these obstacles by itself. Based on geometric inferences, the proposed approach requires no prior training or any knowledge of the camera’s internal parameters,making it practical for robots navigation. Furthermore, the method is robust to errors in calibration and image noise. We compared the errors from corners of estimated non-Manhattan obstacles against the ground truth. Furthermore, we evaluate the validity of convergence of differences between the robot orientation and the posture of non-Manhattan obstacles. The experimental results showed that our method is capable of avoiding non-Manhattan obstacles, meeting the requirements for indoor robot navigation.展开更多
This paper presents a novel dynamic A^*path finding algorithm and 3D lidar based local obstacle avoidance strategy for an autonomous vehicle.3D point cloud data is collected and analyzed in real time.Local obstacles a...This paper presents a novel dynamic A^*path finding algorithm and 3D lidar based local obstacle avoidance strategy for an autonomous vehicle.3D point cloud data is collected and analyzed in real time.Local obstacles are detected online and a 2D local obstacle grid map is constructed at 10 Hz/s.The A^*path finding algorithm is employed to generate a local path in this local obstacle grid map by considering both the target position and obstacles.The vehicle avoids obstacles under the guidance of the generated local path.Experiment results have shown the effectiveness of the obstacle avoidance navigation algorithm proposed.展开更多
A method of environment mapping using laser-based light detection and ranging （LIDAR） is proposed in this paper. This method not only has a good detection performance in a wide range of detection angles, but also fa...A method of environment mapping using laser-based light detection and ranging （LIDAR） is proposed in this paper. This method not only has a good detection performance in a wide range of detection angles, but also facilitates the detection of dynamic and hollowed-out obstacles. Essentially using this method, an improved clustering algorithm based on fast search and discovery of density peaks （CBFD） is presented to extract various obstacles in the environment map. By comparing with other cluster algorithms, CBFD can obtain a favorable number of clusterings automatically. Furthermore, the experiments show that CBFD is better and more robust in functionality and performance than the K-means and iterative self-organizing data analysis techniques algorithm （ISODATA）.展开更多
This work proposes an online collaborative hunting strategy for multi-robot systems based on obstacle-avoiding Voronoi cells in a complex dynamic environment. This involves firstly designing the construction method us...This work proposes an online collaborative hunting strategy for multi-robot systems based on obstacle-avoiding Voronoi cells in a complex dynamic environment. This involves firstly designing the construction method using a support vector machine(SVM) based on the definition of buffered Voronoi cells(BVCs). Based on the safe collision-free region of the robots, the boundary weights between the robots and the obstacles are dynamically updated such that the robots are tangent to the buffered Voronoi safety areas without intersecting with the obstacles. Then, the robots are controlled to move within their own buffered Voronoi safety area to achieve collision-avoidance with other robots and obstacles. The next step involves proposing a hunting method that optimizes collaboration between the pursuers and evaders. Some hunting points are generated and distributed evenly around a circle. Next, the pursuers are assigned to match the optimal points based on the Hungarian algorithm.Then, a hunting controller is designed to improve the containment capability and minimize containment time based on collision risk. Finally, simulation results have demonstrated that the proposed cooperative hunting method is more competitive in terms of time and travel distance.展开更多
A robot intelligent path planning system RIPPS is developed, which can be utilized for a robot off line programming tool. The system consists of three parts: geometric modeler, kinematic modeler and path planer. The...A robot intelligent path planning system RIPPS is developed, which can be utilized for a robot off line programming tool. The system consists of three parts: geometric modeler, kinematic modeler and path planer. The geometric modeler is used to construct the robot working environment cluttered with obstacles and the robot kinematic modeler to define robot manipulators by the input parameters. Giving robot start and the goal configurations, the path planer can produce a quasi optimal path. By transforming obstacles into the C space to form C obstacles, the path searching is performed in C space. The planning simulations are performed on a SGI workstation, the future research is to implement the planer on a commercial robot manipulators.展开更多
文摘In the context of security systems,adequate signal coverage is paramount for the communication between security personnel and the accurate positioning of personnel.Most studies focus on optimizing base station deployment under the assumption of static obstacles,aiming to maximize the perception coverage of wireless RF(Radio Frequency)signals and reduce positioning blind spots.However,in practical security systems,obstacles are subject to change,necessitating the consideration of base station deployment in dynamic environments.Nevertheless,research in this area still needs to be conducted.This paper proposes a Dynamic Indoor Environment Beacon Deployment Algorithm(DIE-BDA)to address this problem.This algorithm considers the dynamic alterations in obstacle locations within the designated area.It determines the requisite number of base stations,the requisite time,and the area’s practical and overall signal coverage rates.The experimental results demonstrate that the algorithm can calculate the deployment strategy in 0.12 s following a change in obstacle positions.Experimental results show that the algorithm in this paper requires 0.12 s to compute the deployment strategy after the positions of obstacles change.With 13 base stations,it achieves an effective coverage rate of 93.5%and an overall coverage rate of 97.75%.The algorithm can rapidly compute a revised deployment strategy in response to changes in obstacle positions within security systems,thereby ensuring the efficacy of signal coverage.
文摘The flow field architecture of the proton exchange membrane fuel cell(PEMFC)cathode critically determines its performance.To enhance PEMFC operation through structural optimization,trapezoidal obstacles were implemented in the cathode flow channels.The height dependence of these obstacles was systematically investigated,revealing that a 0.7 mm obstacle height enhanced mass transfer from channels to the gas diffusion layer(GDL)compared to conventional triple-serpentine designs.This configuration achieved a 12.08%increase in limiting current density alongside improved water management.Subsequent studies on obstacle distribution density identified 75%density as optimal,delivering maximum net power density with 10.6%lower pressure drop than full-density arrangements.
文摘Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate obstacles.After spinal cord injury,stepping over an obstacle becomes challenging.Stepping over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor cortex.Sensory information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain balance.After spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an obstacle.Therefore,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.
文摘Intelligent robots are increasingly being deployed across industries ranging from manufacturing to household applications and outdoor exploration.Their autonomous obstacle avoidance capabilities in complex environments have become a critical factor determining operational stability.Multimodal perception technology,which integrates visual,auditory,tactile,and LiDAR data,provides robots with comprehensive environmental awareness.By establishing efficient autonomous obstacle avoidance decision-making mechanisms based on this information,the system’s adaptability to challenging scenarios can be significantly enhanced.This study investigates the integration of multimodal perception with autonomous obstacle avoidance decision-making,analyzing the acquisition and processing of perceptual information,core modules and logic of decision-making mechanisms,and proposing optimization strategies for specific scenarios.The research aims to provide theoretical references for advancing autonomous obstacle avoidance technology in intelligent robots,enabling safer and more flexible movement in diverse environments.
基金Supported by National Natural Science Foundation of China (Grant Nos. 52072215, 52221005, 52272386)Beijing Municipal Natrual Science Foundation (Grant No. L243025)+2 种基金National Key R&D Program of China (Grant No. 2022YFB2503003)State Key Laboratory of Intelligent Green Vehicle and Mobilityfundamental Research Funds for the Central Universities
文摘Autonomous trucks have the potential to enhance both safety and convenience in intelligent transportation.However,their maximum speed and ability to navigate a variety of driving conditions,particularly uneven roads,are limited by a high center of gravity,which increases the risk of rollover.Road bulges,sinkholes,and unexpected debris all present additional challenges for autonomous trucks’operational design,which current perception and decisionmaking algorithms often overlook.To mitigate rollover risks and improve adaptability to damaged roads,this paper presents a novel Road Obstacle-Involved Trajectory Planner(ROITP).The planner categorizes road obstacles using a learning-based algorithm.A discrete optimization algorithm selects a multi-objective optimal trajectory while taking into account constraints and objective functions derived from truck dynamics.Validation across various scenarios on a hardware-in-loop platform demonstrates that the proposed planner is effective and feasible for real-time implementation.
基金Supported by Agricultural Science and Technology Innovation Fund of Hunan Province(XCNZ[2021]No.15)Loudi Science and Technology Innovation Program(LKF[2022]29)+1 种基金Applied Characteristic Discipline Construction Project of Hunan Province:Plant ProtectionPostgraduate Research and Innovation Project of Hunan University of Humanities,Science and Technology(ZSCX2022Y12).
文摘[Objectives]This study was conducted to comprehensively understand the changes in gene expression of plants under environmental stress during different growth and development stages.[Methods]The effects of continuous cropping on the roots and leaves of Polygonatum sibiricum were investigated using transcriptome sequencing.Normally-grown first crop P.sibiricum was used as the control group,while continuous cropping plants served as the treatment group.Transcriptomic differences in roots and leaves under different conditions were compared.[Results]The leaf materials of first crop and continuous cropping P.sibiricum(CCLZ vs FCLZ)showed 21916 differentially expressed genes(DEGs),while the root materials of first crop and continuous cropping P.sibiricum(CCRZ vs FCRZ)exhibited 12726 DEGs(the lowest DEG count)(12726).Among them,1896 DEGs were common.GO enrichment analysis revealed that DEGs were mainly enriched in metabolism,cell wall degradation,and pathogen defense.KEGG enrichment analysis indicated that DEGs in CCLZ vs FCLZ and CCRZ vs FCRZ primarily affected hormone signal transduction and pathogen interaction pathways.[Conclusions]This study preliminarily elucidate the regulatory mechanisms in the roots and leaves of continuous cropping P.sibiricum at the molecular level,providing reference for research on its adaptation to continuous cropping.
基金Social Science Foundation Project of Jiangxi Province,No.24GL61D。
文摘In recent years, the uncontrollable risks of urban production-living-ecological(PLE)space have increased sharply, making resilience enhancement essential for sustainable urban development. Based on the social-ecological system(SES) theory, this study constructs an assessment framework for urban PLE space resilience by analyzing its inherent characteristics. The central urban area of Ganzhou city is taken as a case study to evaluate urban PLE space resilience and diagnose its obstacles. The results are as follows: The PLE space resilience in the central urban area of Ganzhou exhibits gradations and substantial spatial differentiation. The ecological space resilience in the study area was the highest, followed by that of production space, while living space resilience was the lowest. The primary factors influencing PLE space resilience are concentrated in the dimensions of robustness and adaptability. In particular, the robustness of the PLE space is relatively low. Based on these results, targeted spatial resilience governance strategies for the PLE space have been proposed. These strategies serve as theoretical and technical references for the study area. By adopting the PLE space perspective, this paper enriches resilience research and provide theoretical support for sustainable urban development.
基金supported by the National Science Fund for Distinguished Young Scholars(52425211)BIT Research Fund Program for Young Scholars(XSQD-202201005).
文摘A three-dimensional path-planning approach has been developed to coordinate multiple fixed-wing unmanned aerial vehicles(UAVs)while avoiding collisions.The hierarchical path-planning architecture that divides the path-planning process into two layers is proposed by designing the velocityobstacle strategy for satisfying timeliness and effectiveness.The upper-level layer focuses on creating an efficient Dubins initial path considering the dynamic constraints of the fixed wing.Subsequently,the lower-level layer detects potential collisions and adjusts its flight paths to avoid collisions by using the threedimensional velocity obstacle method,which describes the maneuvering space of collision avoidance as the intersection space of half space.To further handle the dynamic and collisionavoidance constraints,a priority mechanism is designed to ensure that the adjusted path is still feasible for fixed-wing UAVs.Simulation experiments demonstrate the effectiveness of the proposed method.
基金Under the auspices of National Natural Science Foundation of China(No.42371185)。
文摘Under the new development pattern,promoting the balanced development of the regional life service level is the key to attaining the goal of meeting people’s need for an improved life.This study constructed an index system with six dimensions,namely,economic base,innovation drive,living environment,transportation,public services and life security,and explored the balanced characteristics and obstacles of the life service level in the Yangtze River Delta,China in 2020 using the Gini coefficient,the standard deviation ellipse,the global spatial autocorrelation,the equilibrium entropy and the obstacle degree model.Results show that:1)the current overall level of life services in the Yangtze River Delta is in relative equilibrium,and the Gini coefficient of three dimensions,namely,economic base,innovation drive and life security,is relatively low and on the verge of imbalance.2)The spatial pattern of the six dimensions of the overall level of the life service is oriented toward the‘southeast-northwest’direction with significant spatial differentiation and spatial agglomeration.3)At present,most of the cities have a comparative advantage in the coordination of their life services,and the potential of their life service system shows room for further improvement in the future.4)Currently,the quality of economic development,talent concentration,innovation inputs,innovation outputs,basic education,health care,cultural sharing,the living standards of the urban and rural residents and the construction of a transportation system are the main factors constraining the improvement of the level of life services in the Yangtze River Delta.This study attempts to research on the evaluation and measurement of regional life service level in the new era,and provides a reference for the promotion of regional coordination and sustainable development.
基金supported in part by the National Natural Science Foundation of China under Grants 62303098 and 62173073in part by China Postdoctoral Science Foundation under Grant 2022M720679+1 种基金in part by the Central University Basic Research Fund of China under Grant N2304021in part by the Liaoning Provincial Science and Technology Plan Project-Technology Innovation Guidance of the Science and Technology Department under Grant 2023JH1/10400011.
文摘Despite its immense potential,the application of digital twin technology in real industrial scenarios still faces numerous challenges.This study focuses on industrial assembly lines in sectors such as microelectronics,pharmaceuticals,and food packaging,where precision and speed are paramount,applying digital twin technology to the robotic assembly process.The innovation of this research lies in the development of a digital twin architecture and system for Delta robots that is suitable for real industrial environments.Based on this system,a deep reinforcement learning algorithm for obstacle avoidance path planning in Delta robots has been developed,significantly enhancing learning efficiency through an improved intermediate reward mechanism.Experiments on communication and interaction between the digital twin system and the physical robot validate the effectiveness of this method.The system not only enhances the integration of digital twin technology,deep reinforcement learning and robotics,offering an efficient solution for path planning and target grasping inDelta robots,but also underscores the transformative potential of digital twin technology in intelligent manufacturing,with extensive applicability across diverse industrial domains.
基金Under the auspices of National Natural Science Foundation of China(No.42271222)Natural Science Foundation of Gansu Province(No.22JR5RA130)。
文摘Rural resilience,a core capability for addressing systemic risks and enabling sustainable development,is increasingly vital to promoting urban-rural integrated development and rural revitalization strategies.However,current research lacks exploration of the collaborative mechanisms between rural economic resilience(RER)and rural social resilience(RSR)in ecologically vulnerable areas.Based on the practical context of rural sustainable development in such regions,this study investigates the interaction between RER and RSR from a resilience coordination perspective.In this paper,a rural resilience evaluation framework for collaborative development of economic and social resilience was established.By employing the coupling coordination degree model,obstacle degree model,and equilibrium entropy model,this paper examines the synergies,constraints,and potential of rural resilience subsystems in Jinchang City,Gansu Province,China,in 2020.The results reveal that:1)RER contributes to RSR by stabilizing the economy,enhancing community adaptability,and driving modernization.In turn,RSR strengthens RER by mitigating instability,building social capital,and fostering confidence—together forming a mutually reinforcing coupling mechanism.2)The rural economic and social resilience level in Jinchang City remains generally low with spatially clustered patterns,while the coupling coordination degree is at an intermediate level overall,with 62.59%of villages exhibiting unbalanced development between rural economic and social resilience.3)RER and RSR demonstrate synergistic degradation in ecologically vulnerable areas,where low-level rural economic and social resilience induce integrated systemic deterioration.4)Considering the unbalanced development of rural economic and social resilience in ecologically fragile areas,differentiated coordination pathways are proposed for three village typologies:RER-lagging villages,RSR-lagging villages,and villages where RER and RSR develop synchronously but lack effective coordination.These findings offer spatial governance strategies and practical guidance for enhancing rural resilience and advancing sustainable development in ecologically vulnerable regions.
文摘Introduction: Vaccination faces several obstacles in the fight against COVID-19, yet it has been identified as one of the most effective means of preventing new epidemics of COVID-19. The aim was to contribute to improving vaccination coverage against COVID-19 in the Kindu health zone. Method: We conducted a cross-sectional descriptive study with an analytical focus, using a questionnaire that enabled us to carry out a survey from October 03 to 30, 2022. Our target study population was residents of the Kindu health zone. A total of 420 subjects participated in our study, including 42 per site. Results: The study revealed a low proportion of vaccinated subjects (38.3%) and a high proportion of non-vaccinated subjects (61.70%). Non-belief in the efficacy of vaccines (p = 0.001), infodemia (p = 0.001) and respect for ethnic norms (p = 0.001) were identified as perceived barriers to vaccination. Fear of being branded with the “666” beast badge (p = 0.004) as the perceived severity. Respondents’ perceptions of mass vaccination against COVID-19 are mixed, and their opinions and expectations of COVID-19 vaccination in the town of Kindu are divided. Conclusion: In order to increase the proportion of people vaccinated against COVID-19, it is suggested here to increase the population’s ability to detect false information through a well-structured communication and health education program.
基金supported by the Aeronautical Science Foundation of China(20135584010)
文摘Focusing on obstacle avoidance in three-dimensional space for unmanned aerial vehicle(UAV), the direct obstacle avoidance method in dynamic space based on three-dimensional velocity obstacle spherical cap is proposed, which quantifies the influence of threatening obstacles through velocity obstacle spherical cap parameters. In addition, the obstacle avoidance schemes of any point on the critical curve during the multi-obstacles avoidance are given. Through prediction, the insertion point for the obstacle avoidance can be obtained and the flight path can be replanned. Taking the Pythagorean Hodograph(PH) curve trajectory re-planning as an example, the three-dimensional direct obstacle avoidance method in dynamic space is tested. Simulation results show that the proposed method can realize the online obstacle avoidance trajectory re-planning, which increases the flexibility of obstacle avoidance greatly.
文摘First at all, it introduced the concept and the damages of continuous cropping obstacle. Then, it analyzed the causes of continuous cropping obstacles for Atractylodes macrocephala Koidz. In the end, in order to provide guidance for pro- moting sustainable development of Atractylodes macrocephala Koidz industry in Pingjiang County, it put forward some control methods for eliminating continuous cropping obstacles of Atractylodes macrocephala Koidz, including breeding varieties with high resistance; applying rotation cropping and intercropping reasonable; rational fertilization and soil disinfection; introducing antagonistic bacterial and eliminating au- tointoxication.
基金National Key R&D Program of China(No.2017YFB1201003-020)Science and Technology Project of Gansu Education Department(No.2015B-041)
文摘The detection of obstacles in a dynamic environment is a hot and difficult problem.A method of autonomously detecting obstacles based on laser radar is proposed as a safety auxiliary structure of tram.The nearest neighbor method is used for spatial obstacles clustering from laser radar data.By analyzing the characteristics of obstacles,the types of obstacles are determined by time correlation.Experiments were carried out on the developed unmanned aerial vehicle(UAV),and the experimental results verify the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China(61771146,61375122)the National Thirteen 5-Year Plan for Science and Technology(2017YFC1703303)in part by Shanghai Science and Technology Development Funds(13dz2260200,13511504300)。
文摘Monocular vision-based navigation is a considerable ability for a home mobile robot. However, due to diverse disturbances, helping robots avoid obstacles, especially nonManhattan obstacles, remains a big challenge. In indoor environments, there are many spatial right-corners that are projected into two dimensional projections with special geometric configurations. These projections, which consist of three lines,might enable us to estimate their position and orientation in 3 D scenes. In this paper, we present a method for home robots to avoid non-Manhattan obstacles in indoor environments from a monocular camera. The approach first detects non-Manhattan obstacles. Through analyzing geometric features and constraints,it is possible to estimate posture differences between orientation of the robot and non-Manhattan obstacles. Finally according to the convergence of posture differences, the robot can adjust its orientation to keep pace with the pose of detected non-Manhattan obstacles, making it possible avoid these obstacles by itself. Based on geometric inferences, the proposed approach requires no prior training or any knowledge of the camera’s internal parameters,making it practical for robots navigation. Furthermore, the method is robust to errors in calibration and image noise. We compared the errors from corners of estimated non-Manhattan obstacles against the ground truth. Furthermore, we evaluate the validity of convergence of differences between the robot orientation and the posture of non-Manhattan obstacles. The experimental results showed that our method is capable of avoiding non-Manhattan obstacles, meeting the requirements for indoor robot navigation.
基金the National Natural Science Foundation of China(No.51577112,51575328)Science and Technology Commission of Shanghai Municipality Project(No.16511108600).
文摘This paper presents a novel dynamic A^*path finding algorithm and 3D lidar based local obstacle avoidance strategy for an autonomous vehicle.3D point cloud data is collected and analyzed in real time.Local obstacles are detected online and a 2D local obstacle grid map is constructed at 10 Hz/s.The A^*path finding algorithm is employed to generate a local path in this local obstacle grid map by considering both the target position and obstacles.The vehicle avoids obstacles under the guidance of the generated local path.Experiment results have shown the effectiveness of the obstacle avoidance navigation algorithm proposed.
基金Supported by the National Natural Science Foundation of China(61103157)
文摘A method of environment mapping using laser-based light detection and ranging （LIDAR） is proposed in this paper. This method not only has a good detection performance in a wide range of detection angles, but also facilitates the detection of dynamic and hollowed-out obstacles. Essentially using this method, an improved clustering algorithm based on fast search and discovery of density peaks （CBFD） is presented to extract various obstacles in the environment map. By comparing with other cluster algorithms, CBFD can obtain a favorable number of clusterings automatically. Furthermore, the experiments show that CBFD is better and more robust in functionality and performance than the K-means and iterative self-organizing data analysis techniques algorithm （ISODATA）.
基金supported by the National Natural Science Foundation of China (62273007,61973023)Project of Cultivation for Young Top-motch Talents of Beijing Municipal Institutions (BPHR202203032)。
文摘This work proposes an online collaborative hunting strategy for multi-robot systems based on obstacle-avoiding Voronoi cells in a complex dynamic environment. This involves firstly designing the construction method using a support vector machine(SVM) based on the definition of buffered Voronoi cells(BVCs). Based on the safe collision-free region of the robots, the boundary weights between the robots and the obstacles are dynamically updated such that the robots are tangent to the buffered Voronoi safety areas without intersecting with the obstacles. Then, the robots are controlled to move within their own buffered Voronoi safety area to achieve collision-avoidance with other robots and obstacles. The next step involves proposing a hunting method that optimizes collaboration between the pursuers and evaders. Some hunting points are generated and distributed evenly around a circle. Next, the pursuers are assigned to match the optimal points based on the Hungarian algorithm.Then, a hunting controller is designed to improve the containment capability and minimize containment time based on collision risk. Finally, simulation results have demonstrated that the proposed cooperative hunting method is more competitive in terms of time and travel distance.
文摘A robot intelligent path planning system RIPPS is developed, which can be utilized for a robot off line programming tool. The system consists of three parts: geometric modeler, kinematic modeler and path planer. The geometric modeler is used to construct the robot working environment cluttered with obstacles and the robot kinematic modeler to define robot manipulators by the input parameters. Giving robot start and the goal configurations, the path planer can produce a quasi optimal path. By transforming obstacles into the C space to form C obstacles, the path searching is performed in C space. The planning simulations are performed on a SGI workstation, the future research is to implement the planer on a commercial robot manipulators.
