Nonparametric and parametric subset selection procedures are used in the analysis of state homicide rates (SHRs), for the year 2005 and years 2014-2020, to identify subsets of states that contain the “best” (lowest ...Nonparametric and parametric subset selection procedures are used in the analysis of state homicide rates (SHRs), for the year 2005 and years 2014-2020, to identify subsets of states that contain the “best” (lowest SHR) and “worst” (highest SHR) rates with a prescribed probability. A new Bayesian model is developed and applied to the SHR data and the results are contrasted with those obtained with the subset selection procedures. All analyses are applied within the context of a two-way block design.展开更多
The space manipulator is always designed to have 7 degrees of freedom（Dofs）with the consideration of energy limitation,as well as the flexible moving possibility.Therefore,how to plan the trajectory is important to ...The space manipulator is always designed to have 7 degrees of freedom（Dofs）with the consideration of energy limitation,as well as the flexible moving possibility.Therefore,how to plan the trajectory is important to improve the performance of the manipulator.In this paper,the speed of the end effector is configured as a projecting parameter,when a constant acceleration is applied to adjust the velocity.To implement this trajectory planning strategy,an optimization algorithm through the pseudo inverse of Jacobin matrix is designed,which adjusts the weight functions of joints.According to the functional theory,this algorithm is analyzed and the optimal solution is found in numerous sets of planning.A MATLAB simulation platform is established and the results verity the effectiveness of the algorithm.展开更多
Starting from the characteristics of fruit picking,the characteristics of fruit picking robot manipulators and the research state at home and abroad are reviewed.The analysis summarizes the difficulties in fruit picki...Starting from the characteristics of fruit picking,the characteristics of fruit picking robot manipulators and the research state at home and abroad are reviewed.The analysis summarizes the difficulties in fruit picking robotic arm research.Aiming at the configuration of the manipulator,the structure and characteristics of the manipulator with redundant degrees of freedom are introduced,and the feasibility of the redundant mechanism is demonstrated through the current research state of the manipulator.展开更多
The objective of this paper is to quantify the complexity of rank and nuclear norm constrained methods for low rank matrix estimation problems. Specifically, we derive analytic forms of the degrees of freedom for thes...The objective of this paper is to quantify the complexity of rank and nuclear norm constrained methods for low rank matrix estimation problems. Specifically, we derive analytic forms of the degrees of freedom for these types of estimators in several common settings. These results provide efficient ways of comparing different estimators and eliciting tuning parameters. Moreover, our analyses reveal new insights on the behavior of these low rank matrix estimators. These observations are of great theoretical and practical importance. In particular, they suggest that, contrary to conventional wisdom, for rank constrained estimators the total number of free parameters underestimates the degrees of freedom, whereas for nuclear norm penalization, it overestimates the degrees of freedom. In addition, when using most model selection criteria to choose the tuning parameter for nuclear norm penalization, it oftentimes suffices to entertain a finite number of candidates as opposed to a continuum of choices. Numerical examples are also presented to illustrate the practical implications of our results.展开更多
This paper presents a new Center of Gravity （COG） trajectory planning algorithm for a quadruped robot with redundant Degrees of Freedom （DOFs）. Each leg has 7 DOFs, which allow the robot to exploit its kinematic r...This paper presents a new Center of Gravity （COG） trajectory planning algorithm for a quadruped robot with redundant Degrees of Freedom （DOFs）. Each leg has 7 DOFs, which allow the robot to exploit its kinematic redundancy for various locomotion and manipu- lation tasks. Also, the robot can suitably adapt to different environment （e.g., passing through a narrow gap） by simply changing the body posture. However, the robot has significant COG movement during the leg swinging phase due to the heavy leg weights; the weight of all the four legs takes up 80% of the robot＇s total weight. To achieve stable walking in the presence of undesired COG movements, a new COG trajectory planning algorithm was proposed by using a combined Jacobian of COG and centroid of a support polygon including a foot contact constraint. Additionally, the inverse kinematics of each leg was solved by modified improved Jacobian pseudoinverse （mIJP） algorithm. The mIJP algorithm could generate desired trajectories for the joints even when the robot＇s leg is in a singular posture. Owing to these proposed methods, the robot was able to perform various modes of locomotion both in simulations and experiments with improved stability.展开更多
该文针对发射阵列、接收阵列以及多级延迟器均为非均匀配置的双基地MIMO雷达,提出基于时域和空域二次自由度扩展的发射角、接收角以及多普勒频率估计的ESPRIT(Estimating Signal Via Rotational Invariance Techniques)新方法。该方法...该文针对发射阵列、接收阵列以及多级延迟器均为非均匀配置的双基地MIMO雷达,提出基于时域和空域二次自由度扩展的发射角、接收角以及多普勒频率估计的ESPRIT(Estimating Signal Via Rotational Invariance Techniques)新方法。该方法利用双基地MIMO雷达特殊的方向矢量特点(矩阵的Khatri-Rao积形式),对接收信号进行两次行置换以及去冗余处理,实现了时域和空域孔径自由度的二次扩展。然后对新数据进行时空"滑窗"处理,利用ESPRIT算法分别估计出目标的收发角以及多普勒频率。理论和仿真结果表明:在相同阵元和延迟级数情况下,所提算法的估计性能优于四线性分解和多维ESPRIT算法,且能估计出更多的目标,此外,通过最小冗余配置,极大地降低了阵列和延迟器的配置需求,更利于实际工程应用。展开更多
文摘Nonparametric and parametric subset selection procedures are used in the analysis of state homicide rates (SHRs), for the year 2005 and years 2014-2020, to identify subsets of states that contain the “best” (lowest SHR) and “worst” (highest SHR) rates with a prescribed probability. A new Bayesian model is developed and applied to the SHR data and the results are contrasted with those obtained with the subset selection procedures. All analyses are applied within the context of a two-way block design.
基金Supported by the National High Technology Research of China(2015AA043101,2015BAF10B02)Basic Scientific Research(B2220133017)National Natural Science Foundation of China(61503029,61573063)
文摘The space manipulator is always designed to have 7 degrees of freedom（Dofs）with the consideration of energy limitation,as well as the flexible moving possibility.Therefore,how to plan the trajectory is important to improve the performance of the manipulator.In this paper,the speed of the end effector is configured as a projecting parameter,when a constant acceleration is applied to adjust the velocity.To implement this trajectory planning strategy,an optimization algorithm through the pseudo inverse of Jacobin matrix is designed,which adjusts the weight functions of joints.According to the functional theory,this algorithm is analyzed and the optimal solution is found in numerous sets of planning.A MATLAB simulation platform is established and the results verity the effectiveness of the algorithm.
基金National Natural Science Foundation of China(51305402)。
文摘Starting from the characteristics of fruit picking,the characteristics of fruit picking robot manipulators and the research state at home and abroad are reviewed.The analysis summarizes the difficulties in fruit picking robotic arm research.Aiming at the configuration of the manipulator,the structure and characteristics of the manipulator with redundant degrees of freedom are introduced,and the feasibility of the redundant mechanism is demonstrated through the current research state of the manipulator.
基金supported by National Science Foundation of USA (Grant No. DMS1265202)National Institutes of Health of USA (Grant No. 1-U54AI117924-01)
文摘The objective of this paper is to quantify the complexity of rank and nuclear norm constrained methods for low rank matrix estimation problems. Specifically, we derive analytic forms of the degrees of freedom for these types of estimators in several common settings. These results provide efficient ways of comparing different estimators and eliciting tuning parameters. Moreover, our analyses reveal new insights on the behavior of these low rank matrix estimators. These observations are of great theoretical and practical importance. In particular, they suggest that, contrary to conventional wisdom, for rank constrained estimators the total number of free parameters underestimates the degrees of freedom, whereas for nuclear norm penalization, it overestimates the degrees of freedom. In addition, when using most model selection criteria to choose the tuning parameter for nuclear norm penalization, it oftentimes suffices to entertain a finite number of candidates as opposed to a continuum of choices. Numerical examples are also presented to illustrate the practical implications of our results.
文摘This paper presents a new Center of Gravity （COG） trajectory planning algorithm for a quadruped robot with redundant Degrees of Freedom （DOFs）. Each leg has 7 DOFs, which allow the robot to exploit its kinematic redundancy for various locomotion and manipu- lation tasks. Also, the robot can suitably adapt to different environment （e.g., passing through a narrow gap） by simply changing the body posture. However, the robot has significant COG movement during the leg swinging phase due to the heavy leg weights; the weight of all the four legs takes up 80% of the robot＇s total weight. To achieve stable walking in the presence of undesired COG movements, a new COG trajectory planning algorithm was proposed by using a combined Jacobian of COG and centroid of a support polygon including a foot contact constraint. Additionally, the inverse kinematics of each leg was solved by modified improved Jacobian pseudoinverse （mIJP） algorithm. The mIJP algorithm could generate desired trajectories for the joints even when the robot＇s leg is in a singular posture. Owing to these proposed methods, the robot was able to perform various modes of locomotion both in simulations and experiments with improved stability.
文摘该文针对发射阵列、接收阵列以及多级延迟器均为非均匀配置的双基地MIMO雷达,提出基于时域和空域二次自由度扩展的发射角、接收角以及多普勒频率估计的ESPRIT(Estimating Signal Via Rotational Invariance Techniques)新方法。该方法利用双基地MIMO雷达特殊的方向矢量特点(矩阵的Khatri-Rao积形式),对接收信号进行两次行置换以及去冗余处理,实现了时域和空域孔径自由度的二次扩展。然后对新数据进行时空"滑窗"处理,利用ESPRIT算法分别估计出目标的收发角以及多普勒频率。理论和仿真结果表明:在相同阵元和延迟级数情况下,所提算法的估计性能优于四线性分解和多维ESPRIT算法,且能估计出更多的目标,此外,通过最小冗余配置,极大地降低了阵列和延迟器的配置需求,更利于实际工程应用。
