This paper addresses a geometric control algorithm for the attitude tracking problem of the rigid spacecraft modeled on SO(3).Considering the topological and geometric properties of SO(3),we introduced a smooth positi...This paper addresses a geometric control algorithm for the attitude tracking problem of the rigid spacecraft modeled on SO(3).Considering the topological and geometric properties of SO(3),we introduced a smooth positive attitude error function to convert the attitude tracking issue on SO(3)into the stabilization counterpart on its Lie algebra.The error transformation technique was further utilized to ensure the assigned transient and steady state performance of the attitude tracking error with the aid of a well⁃designed assigned⁃time performance function.Then,using the actor⁃critic(AC)neural architecture,an adaptive reinforcement learning approximator was constructed,in which the actor neural network(NN)was utilized to approximate the unknown nonlinearity online.A critic function was introduced to tune the next phase of the actor neural network operation for performance improvement via supervising the system performance.A rigorous stability analysis was presented to show that the assigned system performance can be achieved.Finally,the effectiveness and feasibility of the constructed control strategy was verified by the numerical simulation.展开更多
Italy will host the 17th edition of ITMA, the world’s largest exhibition of textile machinery.It will be held at the Fiera Milano Rhoexhibition centre in Milan,from 12 to 19 November 2015.
为解决RFID领域中多标签识别存在的信息泄露和信息碰撞问题,提出了一种基于预约机制的防碰撞安全认证协议(reservation mechanism for authentication protocol,RMAP)。RMAP可有效抵御窃听、重放、欺骗等攻击,且采用精简杂凑运算次数的...为解决RFID领域中多标签识别存在的信息泄露和信息碰撞问题,提出了一种基于预约机制的防碰撞安全认证协议(reservation mechanism for authentication protocol,RMAP)。RMAP可有效抵御窃听、重放、欺骗等攻击,且采用精简杂凑运算次数的方法,有效地简化了计算量。同时,采用载波监听多点接入技术,通过重传随机数进行帧序号的二次预约和重排,实现标签的无碰撞有序通信和识别效率的最优,解决了现有协议为避免信息碰撞而对标签进行循环性识别导致的识别效率低、读取时间长的问题。对RMAP识别效率的数值分析表明,当待识别标签数量少于1024时,RMAP的最低识别效率为95.15%,高于常用防碰撞协议。展开更多
基金the National Natural Science Foundation of China(Grant Nos.62103171,61773142)the Natural Science Foundation of Fujian Province of China(Grant Nos.2020J05095,2020J05096)the Jiangsu Provincial Double⁃Innovation Doctor Program(Grant Nos.JSSCBS20210993,JSSCBS20211009)。
文摘This paper addresses a geometric control algorithm for the attitude tracking problem of the rigid spacecraft modeled on SO(3).Considering the topological and geometric properties of SO(3),we introduced a smooth positive attitude error function to convert the attitude tracking issue on SO(3)into the stabilization counterpart on its Lie algebra.The error transformation technique was further utilized to ensure the assigned transient and steady state performance of the attitude tracking error with the aid of a well⁃designed assigned⁃time performance function.Then,using the actor⁃critic(AC)neural architecture,an adaptive reinforcement learning approximator was constructed,in which the actor neural network(NN)was utilized to approximate the unknown nonlinearity online.A critic function was introduced to tune the next phase of the actor neural network operation for performance improvement via supervising the system performance.A rigorous stability analysis was presented to show that the assigned system performance can be achieved.Finally,the effectiveness and feasibility of the constructed control strategy was verified by the numerical simulation.
文摘Italy will host the 17th edition of ITMA, the world’s largest exhibition of textile machinery.It will be held at the Fiera Milano Rhoexhibition centre in Milan,from 12 to 19 November 2015.
文摘为解决RFID领域中多标签识别存在的信息泄露和信息碰撞问题,提出了一种基于预约机制的防碰撞安全认证协议(reservation mechanism for authentication protocol,RMAP)。RMAP可有效抵御窃听、重放、欺骗等攻击,且采用精简杂凑运算次数的方法,有效地简化了计算量。同时,采用载波监听多点接入技术,通过重传随机数进行帧序号的二次预约和重排,实现标签的无碰撞有序通信和识别效率的最优,解决了现有协议为避免信息碰撞而对标签进行循环性识别导致的识别效率低、读取时间长的问题。对RMAP识别效率的数值分析表明,当待识别标签数量少于1024时,RMAP的最低识别效率为95.15%,高于常用防碰撞协议。