As a responsible major developing country,China was one of the first countries to sign the Paris Agreement,which represents the general direction of the world’s transition toward green and low-carbon development.Over...As a responsible major developing country,China was one of the first countries to sign the Paris Agreement,which represents the general direction of the world’s transition toward green and low-carbon development.Over the years since then,the country has actively advanced its efforts in building ecological civilization,and proactively implemented the principle of innovative,coordinated,green,open,and shared development,pushing for a comprehensive green transition of its society and economy amid high-quality development.展开更多
A novel iterative technique, the phase descent search detection was proposed. This technique constrained the solution （PDS） algorithm, for M-ary phase shift keying （M-PSK） symbols to have a unit magnitude and it w...A novel iterative technique, the phase descent search detection was proposed. This technique constrained the solution （PDS） algorithm, for M-ary phase shift keying （M-PSK） symbols to have a unit magnitude and it was based on coordinate descent iterations where coordinates were the unknown symbol phases. The PDS algorithm, together with a descent local search （also implemented as a version of the PDS algorithm）, was used multiple times with different initializations in a proposed multiple phase detector; the solution with the minimum cost was then chosen as the final solution. The simulation results show that for highly loaded multiuser scenarios, the proposed technique has a detection performance that is close to the single-user bound. The results also show that the multiple phase detector allows detection in highly overloaded scenarios and it exhibits near-far resistance. In particular, the detector has a performance that is significantly better, and complexity that is significantly lower, than that of the detector based on semi-definite relaxation.展开更多
Multispeed transmissions can enhance the dynamics and economic performance of electric vehicles(EVs),but the coordinated control of the drive motor and gear shift mechanism during gear shifting is still a difficult ch...Multispeed transmissions can enhance the dynamics and economic performance of electric vehicles(EVs),but the coordinated control of the drive motor and gear shift mechanism during gear shifting is still a difficult challenge because gear shifting may cause discomfort to the occupants.To improve the swiftness of gear shifting,this paper proposes a coordinated shift control method based on the dynamic tooth alignment(DTA)algorithm for nonsynchronizer automated mechanical transmissions(NSAMTs)of EVs.After the speed difference between the sleeve(SL)and target dog gear is reduced to a certain value by speed synchronization,angle synchronization is adopted to synchronize the SL quickly to the target tooth slofs angular position predicted by the DTA.A two-speed planetary NS AMT is taken as an example to carry out comparative simulations and bench experiments.Results show that gear shifting duration and maximum jerk are reduced under the shift control with the proposed method,which proves the effectiveness of the proposed coordinated shift control method with DTA.展开更多
星图模拟技术是星图识别算法和星敏感器性能测试的基础。提出一种新的高精度星图模拟方法。该方法分为三个步骤:首先,利用两行轨道数据(TLE,Two-Line Orbital Element)与简化常规/深空扰动的近似解模型(SGP4/SDP4)计算出卫星在轨运行参...星图模拟技术是星图识别算法和星敏感器性能测试的基础。提出一种新的高精度星图模拟方法。该方法分为三个步骤:首先,利用两行轨道数据(TLE,Two-Line Orbital Element)与简化常规/深空扰动的近似解模型(SGP4/SDP4)计算出卫星在轨运行参数,进而获得卫星姿态矩阵;然后,根据星敏感器的方位和俯仰角度,确定星敏感器视场中的导航星及星敏感器安装矩阵,利用小孔成像模型,获得导航星在星敏感器成像面的投影位置;最后,为更准确模拟实际星像点的灰度扩散,在考虑卫星运动引起的恒星像移的基础上,按照二维高斯分布规律置灰度值来模拟星像点像素。在此基础上,还详细分析了不同曝光时间下,恒星像移对恒星位置测量的影响。展开更多
文摘As a responsible major developing country,China was one of the first countries to sign the Paris Agreement,which represents the general direction of the world’s transition toward green and low-carbon development.Over the years since then,the country has actively advanced its efforts in building ecological civilization,and proactively implemented the principle of innovative,coordinated,green,open,and shared development,pushing for a comprehensive green transition of its society and economy amid high-quality development.
文摘A novel iterative technique, the phase descent search detection was proposed. This technique constrained the solution （PDS） algorithm, for M-ary phase shift keying （M-PSK） symbols to have a unit magnitude and it was based on coordinate descent iterations where coordinates were the unknown symbol phases. The PDS algorithm, together with a descent local search （also implemented as a version of the PDS algorithm）, was used multiple times with different initializations in a proposed multiple phase detector; the solution with the minimum cost was then chosen as the final solution. The simulation results show that for highly loaded multiuser scenarios, the proposed technique has a detection performance that is close to the single-user bound. The results also show that the multiple phase detector allows detection in highly overloaded scenarios and it exhibits near-far resistance. In particular, the detector has a performance that is significantly better, and complexity that is significantly lower, than that of the detector based on semi-definite relaxation.
文摘为解决大规模交/直流电力系统多时间尺度动态复杂,现有混合仿真在多速率协调时存在接口延迟和频率损失,影响精度问题,提出了一种基于多速率异步协调的移频分析混合仿真算法。在多区域戴维南等值(multi-area Thevenin equivalence,MATE)框架下,引入基于内插的异步协调机制,有效消除了接口延时;通过扩展移频分析(shifted frequency analysis,SFA)理论并设计通用接口模型,实现不同速率、不同类型模型分区间的无损数据交互。在交/直流测试系统上的算例表明:所提方法即使在分区步长比较大时,仍能准确仿真高频动态,兼顾了仿真精度与效率。
基金This work was supported by the Science and Technology Planning Project of Guangdong Province,China(Grant Nos.2015B010119002 and 2016B010132001).
文摘Multispeed transmissions can enhance the dynamics and economic performance of electric vehicles(EVs),but the coordinated control of the drive motor and gear shift mechanism during gear shifting is still a difficult challenge because gear shifting may cause discomfort to the occupants.To improve the swiftness of gear shifting,this paper proposes a coordinated shift control method based on the dynamic tooth alignment(DTA)algorithm for nonsynchronizer automated mechanical transmissions(NSAMTs)of EVs.After the speed difference between the sleeve(SL)and target dog gear is reduced to a certain value by speed synchronization,angle synchronization is adopted to synchronize the SL quickly to the target tooth slofs angular position predicted by the DTA.A two-speed planetary NS AMT is taken as an example to carry out comparative simulations and bench experiments.Results show that gear shifting duration and maximum jerk are reduced under the shift control with the proposed method,which proves the effectiveness of the proposed coordinated shift control method with DTA.
文摘星图模拟技术是星图识别算法和星敏感器性能测试的基础。提出一种新的高精度星图模拟方法。该方法分为三个步骤:首先,利用两行轨道数据(TLE,Two-Line Orbital Element)与简化常规/深空扰动的近似解模型(SGP4/SDP4)计算出卫星在轨运行参数,进而获得卫星姿态矩阵;然后,根据星敏感器的方位和俯仰角度,确定星敏感器视场中的导航星及星敏感器安装矩阵,利用小孔成像模型,获得导航星在星敏感器成像面的投影位置;最后,为更准确模拟实际星像点的灰度扩散,在考虑卫星运动引起的恒星像移的基础上,按照二维高斯分布规律置灰度值来模拟星像点像素。在此基础上,还详细分析了不同曝光时间下,恒星像移对恒星位置测量的影响。
