A set of permutations is called sign-balanced if the set contains the same number of even permutations as odd permutations.Let S_(n)(σ_(1),σ_(2),...,σ_(r))denote the set of permutations in the symmetric group S_(n)...A set of permutations is called sign-balanced if the set contains the same number of even permutations as odd permutations.Let S_(n)(σ_(1),σ_(2),...,σ_(r))denote the set of permutations in the symmetric group S_(n)which avoid patternsσ_(1),σ_(2),...,σ_(r).The aim of this paper is to investigate when,for certain patternsσ_(1),σ_(2),...,σ_(r),S_(n)(σ_(1),σ_(2),...,σ_(r))is sign-balanced for every integer n>1.We prove that for any{σ_(1),σ_(2),...,σ_(r)}?S_3,if{σ_(1),σ_(2),...,σ_(r)}is sign-balanced except for{132,213,231,312},then S_(n)(σ_(1),σ_(2),...,σ_(r))is sign-balanced for every integer n>1.In addition,we give some results in the case of avoiding some patterns of length 4.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
Efficient and reliable subcarrier power joint allocation is served as a promising problem in cognitive OFDM-based Cognitive Radio Networks (CRN). This paper focuses on optimal subcarrier allocation for OFDM-based CRN....Efficient and reliable subcarrier power joint allocation is served as a promising problem in cognitive OFDM-based Cognitive Radio Networks (CRN). This paper focuses on optimal subcarrier allocation for OFDM-based CRN. We mainly propose subcarrier allocation scheme denoted as Worst Subcarrier Avoiding Water-filling (WSAW), which is based on Rate Adaptive (RA) criterion and three constraints are considered in CRN. The algorithm divides the assignment procedure into two phases. The first phase is an initial subcarrier allocation based on the idea of avoiding selecting the worst subcarrier in order to maximize the transmission rate; while the second phase is an iterative adjustment process which is realized by swapping pairs of subcarriers between arbitrary users. The proposed scheme could assign subcarriers in accordance with channel coherence time. Hence, real time subcarrier allocation could be implemented. Simulation results show that, comparing with the similar existing algorithms, the proposed scheme could achieve larger capacity and a near-optimal BER performance.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
AGRASP-based algorithm called T_GRASP for avoiding typhoon route optimization is suggested to increase the security and effectiveness of ship navigation.One of the worst natural calamities that can disrupt a ship’s n...AGRASP-based algorithm called T_GRASP for avoiding typhoon route optimization is suggested to increase the security and effectiveness of ship navigation.One of the worst natural calamities that can disrupt a ship’s navigation and result in numerous safety mishaps is a typhoon.Currently,the captains manually review the collected weather data and steer clear of typhoons using their navigational expertise.The distribution of heavy winds andwaves produced by the typhoon also changes dynamically as a result of the surrounding large-scale air pressure distribution,which significantly enhances the challenge of the captain’s preparation for avoiding typhoon navigation.It is now necessary to find a solution to the challenge of designing a highsafety and effective ship navigation path to avoid typhoons.The T_GRASP algorithm is suggested to optimize the candidate set’s structure based on the GRASP algorithm’s frame.The algorithm can guarantee the safety of the ship to avoid typhoons and assure high route efficiency by using the lowest risk function,the shortest sailing time,and the least fuel consumption as the objective functions and the ship speed and highest safety as the model constraints.The outcomes of the simulation demonstrate the superiority of the suggested T_GRASP algorithm over both the conventional A∗algorithm and the ant colony algorithm.In addition to addressing issues with the traditional A∗algorithm,like its wide search space and poor efficiency,the proposed algorithm also addresses issues with the ant colony algorithm,like its excessive iterations and sluggish convergence.展开更多
The new era has put forward new requirements for targeted poverty alleviation.Coordinating disaster prevention,mitigation and relief and ecological civilization construction to assist targeted poverty alleviation has ...The new era has put forward new requirements for targeted poverty alleviation.Coordinating disaster prevention,mitigation and relief and ecological civilization construction to assist targeted poverty alleviation has become an important direction for alleviating poverty from the perspective of drawing on advantages and avoiding disadvantages.The Outline of the 13th Five-Year Plan for National Economic and Social Development of the People's Republic of China has planned and deployed to fully implement the task of poverty alleviation.The current poverty alleviation is extending from fixed-point poverty alleviation to collaborative poverty alleviation and targeted poverty alleviation.Combining the needs of disaster response,climate adaptation,resource utilization,ecological construction,and information utilization in poverty-stricken areas,the role of disaster risk monitoring,forecasting and early warning services is displayed.The disaster prevention,mitigation and relief and poverty alleviation in the new era should be integrated into the national poverty alleviation pattern,actively serve poverty alleviation projects of industry development,relocation and ecological protection,deeply explore the value of disaster risk information and improve the effective supply of disaster prevention,mitigation and relief services,letting disaster prevention,mitigation and relief and ecological civilization construction help the implementation of targeted poverty alleviation.展开更多
This paper presents the non-associative and non-commutative properties of the 123-avoiding patterns of Aunu permutation patterns. The generating function of the said patterns has been reported earlier by the author [1...This paper presents the non-associative and non-commutative properties of the 123-avoiding patterns of Aunu permutation patterns. The generating function of the said patterns has been reported earlier by the author [1] [2]. The paper describes how these non-associative and non commutative properties can be established by using the Cayley table on which a binary operation is defined to act on the 123-avoiding and 132-avoiding patterns of Aunu permutations using a pairing scheme. Our results have generated larger matrices from permutations of points of the Aunu patterns of prime cardinality. It follows that the generated symbols can be used in further studies and analysis in cryptography and game theory thereby providing an interdisciplinary approach and applications of these important permutation patterns.展开更多
Ghanaian authorities recently launched a crackdown on illegal gold mining, detaining more than 100 Chinese nationals suspected of illegal gold mining. After consultations between the two countries, the Chinese detaine...Ghanaian authorities recently launched a crackdown on illegal gold mining, detaining more than 100 Chinese nationals suspected of illegal gold mining. After consultations between the two countries, the Chinese detainees were released. Most of the areas mined by Chinese have been shut down.展开更多
This paper describes path re-planning techniques and underwater obstacle avoidance for unmanned surface vehicle(USV) based on multi-beam forward looking sonar(FLS). Near-optimal paths in static and dynamic environment...This paper describes path re-planning techniques and underwater obstacle avoidance for unmanned surface vehicle(USV) based on multi-beam forward looking sonar(FLS). Near-optimal paths in static and dynamic environments with underwater obstacles are computed using a numerical solution procedure based on an A* algorithm. The USV is modeled with a circular shape in 2 degrees of freedom(surge and yaw). In this paper, two-dimensional(2-D) underwater obstacle avoidance and the robust real-time path re-planning technique for actual USV using multi-beam FLS are developed. Our real-time path re-planning algorithm has been tested to regenerate the optimal path for several updated frames in the field of view of the sonar with a proper update frequency of the FLS. The performance of the proposed method was verified through simulations, and sea experiments. For simulations, the USV model can avoid both a single stationary obstacle, multiple stationary obstacles and moving obstacles with the near-optimal trajectory that are performed both in the vehicle and the world reference frame. For sea experiments, the proposed method for an underwater obstacle avoidance system is implemented with a USV test platform. The actual USV is automatically controlled and succeeded in its real-time avoidance against the stationary undersea obstacle in the field of view of the FLS together with the Global Positioning System(GPS) of the USV.展开更多
To date, many studies related to robots have been performed around the world. Many of these studies have assumed operation at locations where entry is difficult, such as disaster sites, and have focused on various ter...To date, many studies related to robots have been performed around the world. Many of these studies have assumed operation at locations where entry is difficult, such as disaster sites, and have focused on various terrestrial robots, such as snake-like, humanoid, spider-type, and wheeled units. Another area of active research in recent years has been aerial robots with small helicopters for operation indoors and outdoors. However,less research has been performed on robots that operate both on the ground and in the air. Accordingly, in this paper, we propose a hybrid aerial/terrestrial robot system. The proposed robot system was developed by equipping a quadcopter with a mechanism for ground movement. It does not use power dedicated to ground movement, and instead uses the flight mechanism of the quadcopter to achieve ground movement as well. Furthermore, we addressed the issue of obstacle avoidance as part of studies on autonomous control. Thus, we found that autonomous control of ground movement and flight was possible for the hybrid aerial/terrestrial robot system, as was autonomous obstacle avoidance by flight when an obstacle appeared during ground movement.展开更多
Fishburn permutations are in bijection with several important combinatorial structures including interval orders.In this paper,we use the method of generating trees to enumerate two classes of pattern-avoiding Fishbur...Fishburn permutations are in bijection with several important combinatorial structures including interval orders.In this paper,we use the method of generating trees to enumerate two classes of pattern-avoiding Fishburn permutations subject to 7 classical statistics simultaneously.The classes of our interest are(321,312)-avoiding and(321,4123)-avoiding Fishburn permutations.The statistics of our interest are ascents,descents,inversions,right-to-left maxima,right-to-left minima,left-to-right maxima and left-to-right minima.Our results generalize a result by Egge.展开更多
Placement and wiring of vast amount of sensor elements on the 3-dimensionally configured robot sur-face to form soft sensor skin is very difficult with the traditional technology. In this paper we propose a new method...Placement and wiring of vast amount of sensor elements on the 3-dimensionally configured robot sur-face to form soft sensor skin is very difficult with the traditional technology. In this paper we propose a new method to realize such a skin.By implanting infrared sensors array in an elastic body, we obtain an elastic and tough sensor skin that can be shaped freely.The developed sensor skin is a large-area, flexi-ble array of infrared sensors with data processing capabilities.Depending on the skin electronics, it en-dows its carrier with an ability to sense its surroundings.The structure, the method of infrared sensor sig-nal processing, and basic experiments of sensor skin are presented. The validity of the infrared sensor skin is investigated by preliminary obstacle avoidance trial.展开更多
As a new means of cooperation, PPP model can break the time and space restrictions, effectively promote the diversified development of investors, and has the characteristics of wide application range, which can provid...As a new means of cooperation, PPP model can break the time and space restrictions, effectively promote the diversified development of investors, and has the characteristics of wide application range, which can provide more diversified investment and financing channels for infrastructure construction projects. PPP project model plays a vital role in the construction process of public service facilities in China. Taking the meaning, characteristics and advantages of PPP model as the starting point, this paper analyzes the types of financial risks of enterprises in PPP projects and the problems in financial risk management, and puts forward some targeted avoidance measures.展开更多
Introduction:Fluorescent probe-based recombinase aided amplification(RAA)offers the advantages of rapidity and simplicity but is limited by the requirement for complex and lengthy probe design,restricting its widespre...Introduction:Fluorescent probe-based recombinase aided amplification(RAA)offers the advantages of rapidity and simplicity but is limited by the requirement for complex and lengthy probe design,restricting its widespread application.Methods:A novel EvaGreen dye-based RAA(EvaGreen-RAA)assay utilizing self-avoiding molecular recognition system(SAMRS)primers was developed for the detection of Pseudomonas fluorescens(PF)and Bacillus cereus(BC)in milk.Conventional RAA was used as a reference method.Sensitivity was evaluated using nucleic acids from recombinant plasmids and simulated milk specimens.Additionally,a dual EvaGreen-RAA assay was investigated for simultaneous detection of mixed BC and PF in simulated milk specimens.Results:The EvaGreen-RAA demonstrated superior sensitivity compared to conventional RAA,with detection limits of 1 copy/μL versus 10 copies/μL for both BC and PF plasmids,respectively.In simulated milk specimens,EvaGreen-RAA detected BC and PF at concentrations of 100 CFU/mL and 200 CFU/mL,respectively,compared to 400 CFU/mL and 600 CFU/mL for conventional RAA.The dual EvaGreen-RAA assay successfully detected mixed BC and PF in simulated milk specimens at concentrations of 200 CFU/mL for each pathogen.Conclusion:The EvaGreen-RAA assay demonstrated significant advantages in terms of simplicity and enhanced sensitivity compared to fluorescent probe-based RAA,offering a novel approach for developing multiplex pathogen detection systems using melting curve analysis.展开更多
This paper presents an intelligent patrol and security robot integrating 2D LiDAR and RGB-D vision sensors to achieve semantic simultaneous localization and mapping(SLAM),real-time object recognition,and dynamic obsta...This paper presents an intelligent patrol and security robot integrating 2D LiDAR and RGB-D vision sensors to achieve semantic simultaneous localization and mapping(SLAM),real-time object recognition,and dynamic obstacle avoidance.The system employs the YOLOv7 deep-learning framework for semantic detection and SLAM for localization and mapping,fusing geometric and visual data to build a high-fidelity 2D semantic map.This map enables the robot to identify and project object information for improved situational awareness.Experimental results show that object recognition reached 95.4%mAP@0.5.Semantic completeness increased from 68.7%(single view)to 94.1%(multi-view)with an average position error of 3.1 cm.During navigation,the robot achieved 98.0%reliability,avoided moving obstacles in 90.0%of encounters,and replanned paths in 0.42 s on average.The integration of LiDAR-based SLAMwith deep-learning–driven semantic perception establishes a robust foundation for intelligent,adaptive,and safe robotic navigation in dynamic environments.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
Background:This study aims to investigate the underlying mechanisms between parental marital conflict and adolescent short video dependence by constructing a chain mediation model,focusing on the mediating roles of ex...Background:This study aims to investigate the underlying mechanisms between parental marital conflict and adolescent short video dependence by constructing a chain mediation model,focusing on the mediating roles of experiential avoidance and emotional disturbance(anxiety,depression,and stress).Methods:Conducted in January 2025,the research recruited 4125 adolescents from multiple Chinese provinces through convenience sampling;after data cleaning,3957 valid participants(1959 males,1998 females)were included.Using a cross-sectional design,measures included parental marital conflict,experiential avoidance,anxiety,depression,stress,and short video dependence.Results:Pearson correlation analysis revealed significant positive correlations among all variables.Mediation analysis using the SPSS PROCESS macro showed that parental marital conflict directly predicted short video dependence(β=0.269,p<0.001),and also significantly predicted experiential avoidance(β=0.519,p<0.001),anxiety(β=0.072,p<0.001),depression(β=0.067,p<0.001),and stress(β=0.048,p<0.05).Experiential avoidance further predicted anxiety(β=0.521,p<0.001),depression(β=0.489,p<0.001),stress(β=0.408,p<0.001),and short video dependence(β=0.244,p<0.001).While both anxiety(β=0.050,p<0.05)and depression(β=0.116,p<0.001)positively predicted short video dependence,stress did not(β=0.019,p=0.257).Overall,experiential avoidance,anxiety,depression,and stress significantly mediated the relationship between parental marital conflict and short video dependence.Conclusion:These findings confirm that parental marital conflict not only directly influences adolescent short video dependence but also operates through a chain mediation pathway involving experiential avoidance and emotional disturbance,highlighting central psychological mechanisms and providing theoretical support for integrated mental health and behavioral interventions.展开更多
To address the critical challenge of risk perception and assessment for autonomous vehicles in dynamic interactive envi-ronments,this study proposes a semi-supervised spatiotemporal interaction risk cognition network ...To address the critical challenge of risk perception and assessment for autonomous vehicles in dynamic interactive envi-ronments,this study proposes a semi-supervised spatiotemporal interaction risk cognition network with attention mecha-nism(SS-SIRCN),inspired by the behavioral adaptation patterns of biological groups under external threats.First,by thoroughly analyzing the dynamic interaction characteristics exhibited by typical biological collectives when exposed to risk,the study reveals the underlying patterns of trajectory changes influenced by external danger.Then,an attention-based spatiotemporal risk cognition network is designed to establish a mapping between driving behavior features and potential driving risks.Finally,a semi-supervised learning framework is employed to enable risk assessment for autono-mous vehicles using only a small amount of labeled data.Experimental results on real-world vehicle trajectory datasets demonstrate that the proposed method achieves a risk prediction accuracy of 90.76%,outperforming other baseline models in performance.展开更多
The 'Thucydides Trap' has become a hot concept in academic and political discussions across the world. But does it really exist? Or more specifi cally, is a war inevitable between a rising power and an establi...The 'Thucydides Trap' has become a hot concept in academic and political discussions across the world. But does it really exist? Or more specifi cally, is a war inevitable between a rising power and an established power? Amid the current friction between China and the U.S..展开更多
基金Supported by the National Natural Science Foundation of China(Grant No.12061030)the Natural Science Foundation of Hainan Province(Grant No.122RC652)2023 Excellent Science and Technology Innovation Team of Jiangsu Province Universities(Real-Time Industrial Internet of Things).
文摘A set of permutations is called sign-balanced if the set contains the same number of even permutations as odd permutations.Let S_(n)(σ_(1),σ_(2),...,σ_(r))denote the set of permutations in the symmetric group S_(n)which avoid patternsσ_(1),σ_(2),...,σ_(r).The aim of this paper is to investigate when,for certain patternsσ_(1),σ_(2),...,σ_(r),S_(n)(σ_(1),σ_(2),...,σ_(r))is sign-balanced for every integer n>1.We prove that for any{σ_(1),σ_(2),...,σ_(r)}?S_3,if{σ_(1),σ_(2),...,σ_(r)}is sign-balanced except for{132,213,231,312},then S_(n)(σ_(1),σ_(2),...,σ_(r))is sign-balanced for every integer n>1.In addition,we give some results in the case of avoiding some patterns of length 4.
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Supported by the National Natural Science Foundation of China (NSFC) (No. 61102066)the China Postdoctoral Science Foundation (Grant No. 2012M511365)the Scientific Research Project of Zhejiang Provincial Education Department (No. Y201119890)
文摘Efficient and reliable subcarrier power joint allocation is served as a promising problem in cognitive OFDM-based Cognitive Radio Networks (CRN). This paper focuses on optimal subcarrier allocation for OFDM-based CRN. We mainly propose subcarrier allocation scheme denoted as Worst Subcarrier Avoiding Water-filling (WSAW), which is based on Rate Adaptive (RA) criterion and three constraints are considered in CRN. The algorithm divides the assignment procedure into two phases. The first phase is an initial subcarrier allocation based on the idea of avoiding selecting the worst subcarrier in order to maximize the transmission rate; while the second phase is an iterative adjustment process which is realized by swapping pairs of subcarriers between arbitrary users. The proposed scheme could assign subcarriers in accordance with channel coherence time. Hence, real time subcarrier allocation could be implemented. Simulation results show that, comparing with the similar existing algorithms, the proposed scheme could achieve larger capacity and a near-optimal BER performance.
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AGRASP-based algorithm called T_GRASP for avoiding typhoon route optimization is suggested to increase the security and effectiveness of ship navigation.One of the worst natural calamities that can disrupt a ship’s navigation and result in numerous safety mishaps is a typhoon.Currently,the captains manually review the collected weather data and steer clear of typhoons using their navigational expertise.The distribution of heavy winds andwaves produced by the typhoon also changes dynamically as a result of the surrounding large-scale air pressure distribution,which significantly enhances the challenge of the captain’s preparation for avoiding typhoon navigation.It is now necessary to find a solution to the challenge of designing a highsafety and effective ship navigation path to avoid typhoons.The T_GRASP algorithm is suggested to optimize the candidate set’s structure based on the GRASP algorithm’s frame.The algorithm can guarantee the safety of the ship to avoid typhoons and assure high route efficiency by using the lowest risk function,the shortest sailing time,and the least fuel consumption as the objective functions and the ship speed and highest safety as the model constraints.The outcomes of the simulation demonstrate the superiority of the suggested T_GRASP algorithm over both the conventional A∗algorithm and the ant colony algorithm.In addition to addressing issues with the traditional A∗algorithm,like its wide search space and poor efficiency,the proposed algorithm also addresses issues with the ant colony algorithm,like its excessive iterations and sluggish convergence.
基金Supported by China Postdoctoral Science Foundation(2019T120114,2019M650756)Central Asian Atmospheric Science Research Fund(CAAS201804)
文摘The new era has put forward new requirements for targeted poverty alleviation.Coordinating disaster prevention,mitigation and relief and ecological civilization construction to assist targeted poverty alleviation has become an important direction for alleviating poverty from the perspective of drawing on advantages and avoiding disadvantages.The Outline of the 13th Five-Year Plan for National Economic and Social Development of the People's Republic of China has planned and deployed to fully implement the task of poverty alleviation.The current poverty alleviation is extending from fixed-point poverty alleviation to collaborative poverty alleviation and targeted poverty alleviation.Combining the needs of disaster response,climate adaptation,resource utilization,ecological construction,and information utilization in poverty-stricken areas,the role of disaster risk monitoring,forecasting and early warning services is displayed.The disaster prevention,mitigation and relief and poverty alleviation in the new era should be integrated into the national poverty alleviation pattern,actively serve poverty alleviation projects of industry development,relocation and ecological protection,deeply explore the value of disaster risk information and improve the effective supply of disaster prevention,mitigation and relief services,letting disaster prevention,mitigation and relief and ecological civilization construction help the implementation of targeted poverty alleviation.
文摘This paper presents the non-associative and non-commutative properties of the 123-avoiding patterns of Aunu permutation patterns. The generating function of the said patterns has been reported earlier by the author [1] [2]. The paper describes how these non-associative and non commutative properties can be established by using the Cayley table on which a binary operation is defined to act on the 123-avoiding and 132-avoiding patterns of Aunu permutations using a pairing scheme. Our results have generated larger matrices from permutations of points of the Aunu patterns of prime cardinality. It follows that the generated symbols can be used in further studies and analysis in cryptography and game theory thereby providing an interdisciplinary approach and applications of these important permutation patterns.
文摘Ghanaian authorities recently launched a crackdown on illegal gold mining, detaining more than 100 Chinese nationals suspected of illegal gold mining. After consultations between the two countries, the Chinese detainees were released. Most of the areas mined by Chinese have been shut down.
基金supported by the Ministry of Science and Technology of Thailand
文摘This paper describes path re-planning techniques and underwater obstacle avoidance for unmanned surface vehicle(USV) based on multi-beam forward looking sonar(FLS). Near-optimal paths in static and dynamic environments with underwater obstacles are computed using a numerical solution procedure based on an A* algorithm. The USV is modeled with a circular shape in 2 degrees of freedom(surge and yaw). In this paper, two-dimensional(2-D) underwater obstacle avoidance and the robust real-time path re-planning technique for actual USV using multi-beam FLS are developed. Our real-time path re-planning algorithm has been tested to regenerate the optimal path for several updated frames in the field of view of the sonar with a proper update frequency of the FLS. The performance of the proposed method was verified through simulations, and sea experiments. For simulations, the USV model can avoid both a single stationary obstacle, multiple stationary obstacles and moving obstacles with the near-optimal trajectory that are performed both in the vehicle and the world reference frame. For sea experiments, the proposed method for an underwater obstacle avoidance system is implemented with a USV test platform. The actual USV is automatically controlled and succeeded in its real-time avoidance against the stationary undersea obstacle in the field of view of the FLS together with the Global Positioning System(GPS) of the USV.
文摘To date, many studies related to robots have been performed around the world. Many of these studies have assumed operation at locations where entry is difficult, such as disaster sites, and have focused on various terrestrial robots, such as snake-like, humanoid, spider-type, and wheeled units. Another area of active research in recent years has been aerial robots with small helicopters for operation indoors and outdoors. However,less research has been performed on robots that operate both on the ground and in the air. Accordingly, in this paper, we propose a hybrid aerial/terrestrial robot system. The proposed robot system was developed by equipping a quadcopter with a mechanism for ground movement. It does not use power dedicated to ground movement, and instead uses the flight mechanism of the quadcopter to achieve ground movement as well. Furthermore, we addressed the issue of obstacle avoidance as part of studies on autonomous control. Thus, we found that autonomous control of ground movement and flight was possible for the hybrid aerial/terrestrial robot system, as was autonomous obstacle avoidance by flight when an obstacle appeared during ground movement.
基金National Natural Science Foundation of China(Grant No.12171362)。
文摘Fishburn permutations are in bijection with several important combinatorial structures including interval orders.In this paper,we use the method of generating trees to enumerate two classes of pattern-avoiding Fishburn permutations subject to 7 classical statistics simultaneously.The classes of our interest are(321,312)-avoiding and(321,4123)-avoiding Fishburn permutations.The statistics of our interest are ascents,descents,inversions,right-to-left maxima,right-to-left minima,left-to-right maxima and left-to-right minima.Our results generalize a result by Egge.
基金Supported by the National Natural Science Foundation of China （No.50105002）.
文摘Placement and wiring of vast amount of sensor elements on the 3-dimensionally configured robot sur-face to form soft sensor skin is very difficult with the traditional technology. In this paper we propose a new method to realize such a skin.By implanting infrared sensors array in an elastic body, we obtain an elastic and tough sensor skin that can be shaped freely.The developed sensor skin is a large-area, flexi-ble array of infrared sensors with data processing capabilities.Depending on the skin electronics, it en-dows its carrier with an ability to sense its surroundings.The structure, the method of infrared sensor sig-nal processing, and basic experiments of sensor skin are presented. The validity of the infrared sensor skin is investigated by preliminary obstacle avoidance trial.
文摘As a new means of cooperation, PPP model can break the time and space restrictions, effectively promote the diversified development of investors, and has the characteristics of wide application range, which can provide more diversified investment and financing channels for infrastructure construction projects. PPP project model plays a vital role in the construction process of public service facilities in China. Taking the meaning, characteristics and advantages of PPP model as the starting point, this paper analyzes the types of financial risks of enterprises in PPP projects and the problems in financial risk management, and puts forward some targeted avoidance measures.
基金Supported by Shandong Province Key Research and Development Plan(Major Scientific and Technological Innovation Project,2023CXGC010711)the National Key R&D Program of China(2021YFC2301102)the National Natural Science Foundation of China(82202593,U23A20106).
文摘Introduction:Fluorescent probe-based recombinase aided amplification(RAA)offers the advantages of rapidity and simplicity but is limited by the requirement for complex and lengthy probe design,restricting its widespread application.Methods:A novel EvaGreen dye-based RAA(EvaGreen-RAA)assay utilizing self-avoiding molecular recognition system(SAMRS)primers was developed for the detection of Pseudomonas fluorescens(PF)and Bacillus cereus(BC)in milk.Conventional RAA was used as a reference method.Sensitivity was evaluated using nucleic acids from recombinant plasmids and simulated milk specimens.Additionally,a dual EvaGreen-RAA assay was investigated for simultaneous detection of mixed BC and PF in simulated milk specimens.Results:The EvaGreen-RAA demonstrated superior sensitivity compared to conventional RAA,with detection limits of 1 copy/μL versus 10 copies/μL for both BC and PF plasmids,respectively.In simulated milk specimens,EvaGreen-RAA detected BC and PF at concentrations of 100 CFU/mL and 200 CFU/mL,respectively,compared to 400 CFU/mL and 600 CFU/mL for conventional RAA.The dual EvaGreen-RAA assay successfully detected mixed BC and PF in simulated milk specimens at concentrations of 200 CFU/mL for each pathogen.Conclusion:The EvaGreen-RAA assay demonstrated significant advantages in terms of simplicity and enhanced sensitivity compared to fluorescent probe-based RAA,offering a novel approach for developing multiplex pathogen detection systems using melting curve analysis.
基金supported by the National Science and Technology Council of under Grant NSTC 114-2221-E-130-007.
文摘This paper presents an intelligent patrol and security robot integrating 2D LiDAR and RGB-D vision sensors to achieve semantic simultaneous localization and mapping(SLAM),real-time object recognition,and dynamic obstacle avoidance.The system employs the YOLOv7 deep-learning framework for semantic detection and SLAM for localization and mapping,fusing geometric and visual data to build a high-fidelity 2D semantic map.This map enables the robot to identify and project object information for improved situational awareness.Experimental results show that object recognition reached 95.4%mAP@0.5.Semantic completeness increased from 68.7%(single view)to 94.1%(multi-view)with an average position error of 3.1 cm.During navigation,the robot achieved 98.0%reliability,avoided moving obstacles in 90.0%of encounters,and replanned paths in 0.42 s on average.The integration of LiDAR-based SLAMwith deep-learning–driven semantic perception establishes a robust foundation for intelligent,adaptive,and safe robotic navigation in dynamic environments.
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Background:This study aims to investigate the underlying mechanisms between parental marital conflict and adolescent short video dependence by constructing a chain mediation model,focusing on the mediating roles of experiential avoidance and emotional disturbance(anxiety,depression,and stress).Methods:Conducted in January 2025,the research recruited 4125 adolescents from multiple Chinese provinces through convenience sampling;after data cleaning,3957 valid participants(1959 males,1998 females)were included.Using a cross-sectional design,measures included parental marital conflict,experiential avoidance,anxiety,depression,stress,and short video dependence.Results:Pearson correlation analysis revealed significant positive correlations among all variables.Mediation analysis using the SPSS PROCESS macro showed that parental marital conflict directly predicted short video dependence(β=0.269,p<0.001),and also significantly predicted experiential avoidance(β=0.519,p<0.001),anxiety(β=0.072,p<0.001),depression(β=0.067,p<0.001),and stress(β=0.048,p<0.05).Experiential avoidance further predicted anxiety(β=0.521,p<0.001),depression(β=0.489,p<0.001),stress(β=0.408,p<0.001),and short video dependence(β=0.244,p<0.001).While both anxiety(β=0.050,p<0.05)and depression(β=0.116,p<0.001)positively predicted short video dependence,stress did not(β=0.019,p=0.257).Overall,experiential avoidance,anxiety,depression,and stress significantly mediated the relationship between parental marital conflict and short video dependence.Conclusion:These findings confirm that parental marital conflict not only directly influences adolescent short video dependence but also operates through a chain mediation pathway involving experiential avoidance and emotional disturbance,highlighting central psychological mechanisms and providing theoretical support for integrated mental health and behavioral interventions.
基金the Jilin Provincial Department of Science and Technology Youth Science and Technology Talent Cultivation Project(20250602051RC)Fundamental Research Funds for the Central Universities(2025-JCXK-19)National Natural Science Foundation of China under Grant 52272417.
文摘To address the critical challenge of risk perception and assessment for autonomous vehicles in dynamic interactive envi-ronments,this study proposes a semi-supervised spatiotemporal interaction risk cognition network with attention mecha-nism(SS-SIRCN),inspired by the behavioral adaptation patterns of biological groups under external threats.First,by thoroughly analyzing the dynamic interaction characteristics exhibited by typical biological collectives when exposed to risk,the study reveals the underlying patterns of trajectory changes influenced by external danger.Then,an attention-based spatiotemporal risk cognition network is designed to establish a mapping between driving behavior features and potential driving risks.Finally,a semi-supervised learning framework is employed to enable risk assessment for autono-mous vehicles using only a small amount of labeled data.Experimental results on real-world vehicle trajectory datasets demonstrate that the proposed method achieves a risk prediction accuracy of 90.76%,outperforming other baseline models in performance.
文摘The 'Thucydides Trap' has become a hot concept in academic and political discussions across the world. But does it really exist? Or more specifi cally, is a war inevitable between a rising power and an established power? Amid the current friction between China and the U.S..
