Abnormal movement states for a mobile robot were identified by four multi-layer perceptron. In the presence ot abnormality, avoidance strategies were designed to guarantee the safety of the robot. Firstly, the kinemat...Abnormal movement states for a mobile robot were identified by four multi-layer perceptron. In the presence ot abnormality, avoidance strategies were designed to guarantee the safety of the robot. Firstly, the kinematics of the normal and abnormal movement states were exploited, 8 kinds of features were extracted. Secondly, 4 multi-layer pereeptrons were employed to classify the features for four 4-driving wheels into 4 kinds of states, i.e. normal, blocked, deadly blocked, and slipping. Finally, avoidance strategies were designed based on this. Experiment results show that the methods can identify most abnormal movement states and avoid the abnormality correctly and timely.展开更多
Co-flowering species may have evolved strategies to avoid or tolerate the adverse effects of heterospecific pollen deposition.However,the precondition for this evolutionary response is spatialetemporal stability,an as...Co-flowering species may have evolved strategies to avoid or tolerate the adverse effects of heterospecific pollen deposition.However,the precondition for this evolutionary response is spatialetemporal stability,an aspect currently understudied.Here,we examined the spatialetemporal stability in conspecific and heterospecific pollen loads on stigmas across 19 co-flowering species in six sub-alpine meadow communities over four consecutive years.We found that,although conspecific and heterospecific pollen loads,as well as proportions of heterospecific pollen,differed significantly among species,with heterospecific pollen proportion ranging from 0.1%to 41.8%,variation in heterospecific pollen proportion among species was stable across different years and communities.The most important predictor of variation in both conspecific and heterospecific pollen loads,as well as heterospecific pollen proportions,was species identity;furthermore,this factor was independent of phylogenetic relationship.The proportion of heterospecific pollen varied less within species that had high proportions of heterospecific pollen.Furthermore,both the proportion of heterospecific pollen and its coefficient of variation were more strongly driven by heterospecific pollen than by conspecific pollen.Our study suggests that variation in stigmatic pollen load among co-flowering species is spatially and temporally consistent,a precondition for the tolerance-avoidance strategy.This study provides new insights into how different plant species respond to heterospecific pollen deposition.展开更多
In order to realize the accurate obstacle avoidance function of intelligent car, we propose an intelligent car obstacle avoidance system based on optimized fuzzy control algorithm. Firstly, the kinematics model of int...In order to realize the accurate obstacle avoidance function of intelligent car, we propose an intelligent car obstacle avoidance system based on optimized fuzzy control algorithm. Firstly, the kinematics model of intelligent car obstacle avoidance is established, and an efficient environment information collection system composed of multiple sensors is designed to realize the comprehensive collection of obstacle information. Then, the optimized fuzzy control system is adopted to improve the position control accuracy and obstacle avoidance ability. Through the physical debugging and joint simulation of the intelligent car fuzzy controller in the MATLAB and Simulink environment, the simulation results show that the control method can make the collision-free path planned by the intelligent car from the initial state to the obstacle avoidance smoother, and at the same time, the obstacle avoidance of the intelligent car. The actual running distance is reduced by about 16%, which can ensure the practicability of the obstacle avoidance system, provide a new guarantee for the safe operation of the car, and also provide a new idea for the development of the unmanned car.展开更多
We investigate a distributed game strategy for unmanned aerial vehicle(UAV)formations with external disturbances and obstacles.The strategy is based on a distributed model predictive control(MPC)framework and Levy fli...We investigate a distributed game strategy for unmanned aerial vehicle(UAV)formations with external disturbances and obstacles.The strategy is based on a distributed model predictive control(MPC)framework and Levy flight based pigeon inspired optimization(LFPIO).First,we propose a non-singular fast terminal sliding mode observer(NFTSMO)to estimate the influence of a disturbance,and prove that the observer converges in fixed time using a Lyapunov function.Second,we design an obstacle avoidance strategy based on topology reconstruction,by which the UAV can save energy and safely pass obstacles.Third,we establish a distributed MPC framework where each UAV exchanges messages only with its neighbors.Further,the cost function of each UAV is designed,by which the UAV formation problem is transformed into a game problem.Finally,we develop LFPIO and use it to solve the Nash equilibrium.Numerical simulations are conducted,and the efficiency of LFPIO based distributed MPC is verified through comparative simulations.展开更多
Aims Grasslands are widely used for production of livestock,which depend on the nutritive value of herbage species.However,there are still large uncertainties as to how grazing,precipitation and growing season interac...Aims Grasslands are widely used for production of livestock,which depend on the nutritive value of herbage species.However,there are still large uncertainties as to how grazing,precipitation and growing season interactively affect herbage nutritive value.Methods Here,based on a grazing experiment with seven grazing intensities in an Inner Mongolian grassland since the year 2005,we analysed nutritive value of four dominant grass species from June to September in both a relatively wetter year(2008)and a drier year(2010).Herbage with high nutritive value is characterized by high concentration of crude protein,high concentration of cellulase digestible organic matter and low concentration of neutral detergent fibre.Important Findings We found that(i)grazing significantly increased the nutritive value of Leymus chinensis,Agropyron michnoi and Cleistogenes squarrosa but had minor effects on the nutritive value of Stipa grandis.(ii)For all species,nutritive values were greater in the wetter year than in the drier year and were greatest in the early growing season(June)and lowest at the end of the growing season(September).Inter-annual and inter-seasonal variations in nutritive value were much greater for L.chinensis and A.michnoi than for C.squarrosa and S.grandis,suggesting higher water use efficiency for the latter two species.(iii)Grazing significantly decreased the drought resistance of three species,but not of S.grandis.(iv)Grazing significantly increased inter-month variation in nutritive value for L.chinensis and A.michnoi but had relatively minor or no effects on that of C.squarrosa and S.grandis.Therefore,grazing effects on species nutritive values showed strong inter-annual and seasonal patterns,and species-specific responses might be related to species traits(i.e.water use efficiency,digestibility).Our results have important implications for ecosystem management of arid and semiarid grasslands under intense grazing and global climatic change.展开更多
The quickly growing development and fierce competition in technical industry make Apps for The Future Inc. (AFF) has risk of losing market share and their customers' trust. Therefore, after the examine of three so...The quickly growing development and fierce competition in technical industry make Apps for The Future Inc. (AFF) has risk of losing market share and their customers' trust. Therefore, after the examine of three solutions which used by Nokia, Motorola and China Unicom based on the selected criteria, the suitable solutions that the AFF managers should follow are creating new flagship product with low price, finding development direction and keep investing. Those solutions could allow companies to keep creating, keep motivating and care their customers, and allow this company to be successful and regain customer trust.展开更多
基金Project (60234030) supported by the National Natural Science Foundation of China
文摘Abnormal movement states for a mobile robot were identified by four multi-layer perceptron. In the presence ot abnormality, avoidance strategies were designed to guarantee the safety of the robot. Firstly, the kinematics of the normal and abnormal movement states were exploited, 8 kinds of features were extracted. Secondly, 4 multi-layer pereeptrons were employed to classify the features for four 4-driving wheels into 4 kinds of states, i.e. normal, blocked, deadly blocked, and slipping. Finally, avoidance strategies were designed based on this. Experiment results show that the methods can identify most abnormal movement states and avoid the abnormality correctly and timely.
基金supported by the National Natural Science Foundation of China(No.32071535 and 32371602)the Key Scientific Research Projects of College and University in Henan Province(No.24ZX001)the Henan Province Foundation for University Key Teacher(No.2020GGJS074).
文摘Co-flowering species may have evolved strategies to avoid or tolerate the adverse effects of heterospecific pollen deposition.However,the precondition for this evolutionary response is spatialetemporal stability,an aspect currently understudied.Here,we examined the spatialetemporal stability in conspecific and heterospecific pollen loads on stigmas across 19 co-flowering species in six sub-alpine meadow communities over four consecutive years.We found that,although conspecific and heterospecific pollen loads,as well as proportions of heterospecific pollen,differed significantly among species,with heterospecific pollen proportion ranging from 0.1%to 41.8%,variation in heterospecific pollen proportion among species was stable across different years and communities.The most important predictor of variation in both conspecific and heterospecific pollen loads,as well as heterospecific pollen proportions,was species identity;furthermore,this factor was independent of phylogenetic relationship.The proportion of heterospecific pollen varied less within species that had high proportions of heterospecific pollen.Furthermore,both the proportion of heterospecific pollen and its coefficient of variation were more strongly driven by heterospecific pollen than by conspecific pollen.Our study suggests that variation in stigmatic pollen load among co-flowering species is spatially and temporally consistent,a precondition for the tolerance-avoidance strategy.This study provides new insights into how different plant species respond to heterospecific pollen deposition.
文摘In order to realize the accurate obstacle avoidance function of intelligent car, we propose an intelligent car obstacle avoidance system based on optimized fuzzy control algorithm. Firstly, the kinematics model of intelligent car obstacle avoidance is established, and an efficient environment information collection system composed of multiple sensors is designed to realize the comprehensive collection of obstacle information. Then, the optimized fuzzy control system is adopted to improve the position control accuracy and obstacle avoidance ability. Through the physical debugging and joint simulation of the intelligent car fuzzy controller in the MATLAB and Simulink environment, the simulation results show that the control method can make the collision-free path planned by the intelligent car from the initial state to the obstacle avoidance smoother, and at the same time, the obstacle avoidance of the intelligent car. The actual running distance is reduced by about 16%, which can ensure the practicability of the obstacle avoidance system, provide a new guarantee for the safe operation of the car, and also provide a new idea for the development of the unmanned car.
基金Project supported by the Science and Technology Innovation 2030 Key Project of“New Generation Artificial Intelligence,”China(No.2018AAA0100803)the National Natural Science Foundation of China(Nos.T2121003,U1913602,U20B2071,91948204,and U19B2033)。
文摘We investigate a distributed game strategy for unmanned aerial vehicle(UAV)formations with external disturbances and obstacles.The strategy is based on a distributed model predictive control(MPC)framework and Levy flight based pigeon inspired optimization(LFPIO).First,we propose a non-singular fast terminal sliding mode observer(NFTSMO)to estimate the influence of a disturbance,and prove that the observer converges in fixed time using a Lyapunov function.Second,we design an obstacle avoidance strategy based on topology reconstruction,by which the UAV can save energy and safely pass obstacles.Third,we establish a distributed MPC framework where each UAV exchanges messages only with its neighbors.Further,the cost function of each UAV is designed,by which the UAV formation problem is transformed into a game problem.Finally,we develop LFPIO and use it to solve the Nash equilibrium.Numerical simulations are conducted,and the efficiency of LFPIO based distributed MPC is verified through comparative simulations.
基金Deutsche Forschungsgemeinschaft(DFG)for funding the research group 536 MAGIM(Matter fluxes of grasslands in Inner Mongolia as influenced by stocking rate)and the subsequent Lot-Grass projectthe Ministry of Education of China(IRT1259).
文摘Aims Grasslands are widely used for production of livestock,which depend on the nutritive value of herbage species.However,there are still large uncertainties as to how grazing,precipitation and growing season interactively affect herbage nutritive value.Methods Here,based on a grazing experiment with seven grazing intensities in an Inner Mongolian grassland since the year 2005,we analysed nutritive value of four dominant grass species from June to September in both a relatively wetter year(2008)and a drier year(2010).Herbage with high nutritive value is characterized by high concentration of crude protein,high concentration of cellulase digestible organic matter and low concentration of neutral detergent fibre.Important Findings We found that(i)grazing significantly increased the nutritive value of Leymus chinensis,Agropyron michnoi and Cleistogenes squarrosa but had minor effects on the nutritive value of Stipa grandis.(ii)For all species,nutritive values were greater in the wetter year than in the drier year and were greatest in the early growing season(June)and lowest at the end of the growing season(September).Inter-annual and inter-seasonal variations in nutritive value were much greater for L.chinensis and A.michnoi than for C.squarrosa and S.grandis,suggesting higher water use efficiency for the latter two species.(iii)Grazing significantly decreased the drought resistance of three species,but not of S.grandis.(iv)Grazing significantly increased inter-month variation in nutritive value for L.chinensis and A.michnoi but had relatively minor or no effects on that of C.squarrosa and S.grandis.Therefore,grazing effects on species nutritive values showed strong inter-annual and seasonal patterns,and species-specific responses might be related to species traits(i.e.water use efficiency,digestibility).Our results have important implications for ecosystem management of arid and semiarid grasslands under intense grazing and global climatic change.
文摘The quickly growing development and fierce competition in technical industry make Apps for The Future Inc. (AFF) has risk of losing market share and their customers' trust. Therefore, after the examine of three solutions which used by Nokia, Motorola and China Unicom based on the selected criteria, the suitable solutions that the AFF managers should follow are creating new flagship product with low price, finding development direction and keep investing. Those solutions could allow companies to keep creating, keep motivating and care their customers, and allow this company to be successful and regain customer trust.
