Automatic partition of Chinese sentence group is very important to the statistical machine translation system based on discourse. This paper presents an approach to this issue： first, each sentence in a discourse is ...Automatic partition of Chinese sentence group is very important to the statistical machine translation system based on discourse. This paper presents an approach to this issue： first, each sentence in a discourse is expressed as a feature vector; second, a special hierarchical clustering algorithm is applied to present a discourse as a sentence group tree. In this paper, local reoccurrence measure is proposed to the selection of key phras and the evaluation of the weight of key phrases. Experimental results show our approach promising.展开更多
We show that the isomorphism problem is solvable in the class of central extensions of word-hyperbolic groups,and that the isomorphism problem for biautomatic groups reduces to that for biautomatic groups with finite ...We show that the isomorphism problem is solvable in the class of central extensions of word-hyperbolic groups,and that the isomorphism problem for biautomatic groups reduces to that for biautomatic groups with finite centre.We describe an algorithm that,given an arbitrary finite presentation of an automatic group Γ,will construct explicit finite models for the skeleta of K(Γ,1) and hence compute the integral homology and cohomology of Γ.展开更多
This paper presents a weight-based group formation tracking control method for air–ground multi-agent systems,where the system consists of unmanned aerial vehicles(UAVs)and unmanned ground vehicles(UGVs).Specifically...This paper presents a weight-based group formation tracking control method for air–ground multi-agent systems,where the system consists of unmanned aerial vehicles(UAVs)and unmanned ground vehicles(UGVs).Specifically,a three-layer directed communication topology consisting of a master leader,group leaders,and followers is designed first.Subsequently,a formation tracking controller is developed,and the stability of the system is proven using Lyapunov theory.Additionally,to address the collision issues that can arise during the grouping and flight of multi-UAV formations,a collision avoidance controller is designed based on a rotational potential field function.Finally,simulation experiments validate that the proposed method can achieve stable and safe grouping,formation,and collaborative tracking of air–ground multi-agent systems.展开更多
基金National High Technology Research and Development Program of China ( No.2006AA01Z139)Young NaturalScience Foundation of Fujian Province of China ( No.2008F3105)+1 种基金Natural Science Foundation of Fujian Province of China ( No.2006J0043)Fund of Key Research Project of Fujian Province of China (No.2006H0038)
文摘Automatic partition of Chinese sentence group is very important to the statistical machine translation system based on discourse. This paper presents an approach to this issue： first, each sentence in a discourse is expressed as a feature vector; second, a special hierarchical clustering algorithm is applied to present a discourse as a sentence group tree. In this paper, local reoccurrence measure is proposed to the selection of key phras and the evaluation of the weight of key phrases. Experimental results show our approach promising.
文摘We show that the isomorphism problem is solvable in the class of central extensions of word-hyperbolic groups,and that the isomorphism problem for biautomatic groups reduces to that for biautomatic groups with finite centre.We describe an algorithm that,given an arbitrary finite presentation of an automatic group Γ,will construct explicit finite models for the skeleta of K(Γ,1) and hence compute the integral homology and cohomology of Γ.
基金supported by the National Natural Science Foundation of China(Grant No.62173242)the Major Science and Technology Plan Project of Hainan(Grant No.ZDKJ2021057)the National Science Fund for Distinguished Young Scholars(Grant No.62225308)
文摘This paper presents a weight-based group formation tracking control method for air–ground multi-agent systems,where the system consists of unmanned aerial vehicles(UAVs)and unmanned ground vehicles(UGVs).Specifically,a three-layer directed communication topology consisting of a master leader,group leaders,and followers is designed first.Subsequently,a formation tracking controller is developed,and the stability of the system is proven using Lyapunov theory.Additionally,to address the collision issues that can arise during the grouping and flight of multi-UAV formations,a collision avoidance controller is designed based on a rotational potential field function.Finally,simulation experiments validate that the proposed method can achieve stable and safe grouping,formation,and collaborative tracking of air–ground multi-agent systems.
