1.Introduction Daily physical activity（PA）participation is crucial to the health and well-being of young children.Along with total physical activity（TPA;all-intensity）,moderate-to-vigorous physical activity（MVPA...1.Introduction Daily physical activity（PA）participation is crucial to the health and well-being of young children.Along with total physical activity（TPA;all-intensity）,moderate-to-vigorous physical activity（MVPA）,or energetic play,is associated with greater health benefits,particularly for preschoolers（3-4 years）,including but not limited to improved bone and skeletal properties and cognitive and psychosocial health.1 Centered on this,both Canada and Australia have recently established 24-Hour Movement Guidelines for the Early Years,recommending that.展开更多
为了提高DV-Hop(Distance Vector-Hop)算法中无线传感器网络节点定位精度,提出一种基于OLPDV-Hop(Optimal Jump Distance and Levy Particle Swarm Optimization DV-Hop)的节点定位算法,对OLPDV-Hop算法选择Windows7的MATLABR2014a系统...为了提高DV-Hop(Distance Vector-Hop)算法中无线传感器网络节点定位精度,提出一种基于OLPDV-Hop(Optimal Jump Distance and Levy Particle Swarm Optimization DV-Hop)的节点定位算法,对OLPDV-Hop算法选择Windows7的MATLABR2014a系统环境依次对比了DV-Hop、BDV-Hop与IPSODV-Hop三种算法比较。在节点总数等于100、锚节点数占比为20%以及25~50m通信半径范围内,算法平均定位误差都发生了减小的情况,之后开始重新升高。四种算法都发生了平均定位误差不断降低的现象,当锚节点的密度上升后,相互间的跳数将会变小,并且OLPDV-Hop算法达到最小的平均定位误差。展开更多
针对DV_Hop(Distance Vector-Hop)算法中定位精度较低的问题,提出一种基于最优跳距与LevyPSO算法的无线传感器网络定位算法,即OLPDV_Hop(Optimal Jump Distance and Levy Particle Swarm Optimization DV_Hop)。首先,通过单跳平均误差...针对DV_Hop(Distance Vector-Hop)算法中定位精度较低的问题,提出一种基于最优跳距与LevyPSO算法的无线传感器网络定位算法,即OLPDV_Hop(Optimal Jump Distance and Levy Particle Swarm Optimization DV_Hop)。首先,通过单跳平均误差修正平均跳距,然后利用接收多锚节点的平均跳距估算节点间距离,使估算距离得以优化,最后利用LevyPSO算法替代最小二乘法求得未知节点位置,LevyPSO算法利用Levy飞行改变粒子移动方向以防陷入局部最优,并通过贪婪的更新评价策略产生最优解,最终得到全局最优。仿真结果表明,OLPDV_Hop算法较DV_Hop算法、IPSODV_Hop(Improved Particle Swarm Optimization DV_Hop)算法和BDV_Hop(Based on DV_Hop)算法在定位精度上有明显改善。展开更多
The click beetle can jump up with a hinge when it is on the dorsal side.This jumping mechanism is simple and suitable as an inspiration for designing a simple,small,and reliable hopping robot.We report a single-legged...The click beetle can jump up with a hinge when it is on the dorsal side.This jumping mechanism is simple and suitable as an inspiration for designing a simple,small,and reliable hopping robot.We report a single-legged robot inspired by the jumping mechanism of click beetles.It is 85 mm high,60 mm long,and 41 mm wide,and weighs about 49 g.The robot has good hopping performance that the hopping height is about 4 times-4.3 times of its body height.It is capable for rescue missions that require to enter enclosed spaces through cracks and narrow channels.In addition,hopping dynamics of the robot is important to understand its jumping mechanism and improve the robot’s hopping performance.But existing dynamic study does not complete the analysis including all stages in the hopping which are pre-hopping,take-off,and air-flying.We propose the decomposition method to study dynamics of the three stages separately,and synthesize them with related parameters.The dynamic synthesis of multi-motion states in a hopping cycle of the single-legged hopping robot is implemented.The hopping performance and dynamic synthesis theory of the robot are verified by simulations and experiments.Our study helps lay the foundation for design and hopping control of simple hopping robot systems.展开更多
In this paper, a split-step 0 （SST） method is introduced and used to solve the non- linear neutral stochastic differential delay equations with Poisson jumps （NSDDEwPJ）. The mean square asymptotic stability of the...In this paper, a split-step 0 （SST） method is introduced and used to solve the non- linear neutral stochastic differential delay equations with Poisson jumps （NSDDEwPJ）. The mean square asymptotic stability of the SST method for nonlinear neutral stochastic differential equations with Poisson jumps is studied. It is proved that under the one-sided Lipschitz condition and the linear growth condition, the SST method with ∈ E （0, 2 -√2） is asymptotically mean square stable for all positive step sizes, and the SST method with ∈ E （2 -√2, 1） is asymptotically mean square stable for some step sizes. It is also proved in this paper that the SST method possesses a bounded absorbing set which is independent of initial data, and the mean square dissipativity of this method is also proved.展开更多
文摘1.Introduction Daily physical activity（PA）participation is crucial to the health and well-being of young children.Along with total physical activity（TPA;all-intensity）,moderate-to-vigorous physical activity（MVPA）,or energetic play,is associated with greater health benefits,particularly for preschoolers（3-4 years）,including but not limited to improved bone and skeletal properties and cognitive and psychosocial health.1 Centered on this,both Canada and Australia have recently established 24-Hour Movement Guidelines for the Early Years,recommending that.
文摘为了提高DV-Hop(Distance Vector-Hop)算法中无线传感器网络节点定位精度,提出一种基于OLPDV-Hop(Optimal Jump Distance and Levy Particle Swarm Optimization DV-Hop)的节点定位算法,对OLPDV-Hop算法选择Windows7的MATLABR2014a系统环境依次对比了DV-Hop、BDV-Hop与IPSODV-Hop三种算法比较。在节点总数等于100、锚节点数占比为20%以及25~50m通信半径范围内,算法平均定位误差都发生了减小的情况,之后开始重新升高。四种算法都发生了平均定位误差不断降低的现象,当锚节点的密度上升后,相互间的跳数将会变小,并且OLPDV-Hop算法达到最小的平均定位误差。
基金This work was financially supported by National Natural Science Foundation of China(Nos.51875528 and 41506116)Zhejiang Provincial Natural Science Foundation of China(No.LY20E050018)+1 种基金China Post-doctoral Science Foundation(No.2016M591991)and Science Foundation of Zhejiang Sci-Tech University(ZSTU)(No.17022183-Y).
文摘The click beetle can jump up with a hinge when it is on the dorsal side.This jumping mechanism is simple and suitable as an inspiration for designing a simple,small,and reliable hopping robot.We report a single-legged robot inspired by the jumping mechanism of click beetles.It is 85 mm high,60 mm long,and 41 mm wide,and weighs about 49 g.The robot has good hopping performance that the hopping height is about 4 times-4.3 times of its body height.It is capable for rescue missions that require to enter enclosed spaces through cracks and narrow channels.In addition,hopping dynamics of the robot is important to understand its jumping mechanism and improve the robot’s hopping performance.But existing dynamic study does not complete the analysis including all stages in the hopping which are pre-hopping,take-off,and air-flying.We propose the decomposition method to study dynamics of the three stages separately,and synthesize them with related parameters.The dynamic synthesis of multi-motion states in a hopping cycle of the single-legged hopping robot is implemented.The hopping performance and dynamic synthesis theory of the robot are verified by simulations and experiments.Our study helps lay the foundation for design and hopping control of simple hopping robot systems.
文摘In this paper, a split-step 0 （SST） method is introduced and used to solve the non- linear neutral stochastic differential delay equations with Poisson jumps （NSDDEwPJ）. The mean square asymptotic stability of the SST method for nonlinear neutral stochastic differential equations with Poisson jumps is studied. It is proved that under the one-sided Lipschitz condition and the linear growth condition, the SST method with ∈ E （0, 2 -√2） is asymptotically mean square stable for all positive step sizes, and the SST method with ∈ E （2 -√2, 1） is asymptotically mean square stable for some step sizes. It is also proved in this paper that the SST method possesses a bounded absorbing set which is independent of initial data, and the mean square dissipativity of this method is also proved.
