In this paper, regression function estimation from independent and identically distributed data is considered. We establish strong pointwise consistency of the famous Nadaraya-Watson estimator under weaker conditions ...In this paper, regression function estimation from independent and identically distributed data is considered. We establish strong pointwise consistency of the famous Nadaraya-Watson estimator under weaker conditions which permit to apply kernels with unbounded support and even not integrable ones and provide a general approach for constructing strongly consistent kernel estimates of regression functions.展开更多
针对通信中软扩频信号伪码序列盲估计困难的问题,提出一种奇异值分解(singular value decomposition,SVD)和K-means聚类相结合的方法。该方法先对接收信号按照一倍伪码周期进行不重叠分段构造数据矩阵。其次对数据矩阵和相似性矩阵分别...针对通信中软扩频信号伪码序列盲估计困难的问题,提出一种奇异值分解(singular value decomposition,SVD)和K-means聚类相结合的方法。该方法先对接收信号按照一倍伪码周期进行不重叠分段构造数据矩阵。其次对数据矩阵和相似性矩阵分别进行SVD完成对伪码序列集合规模数的估计、数据降噪、粗分类以及初始聚类中心的选取。最后通过K-means算法优化分类结果,得到伪码序列的估计值。该算法在聚类之前事先确定聚类数目,大大减少了迭代次数。同时实验结果表明,该算法在信息码元分组小于5 bit,信噪比大于-10 dB时可以准确估计出软扩频信号的伪码序列,性能较同类算法有所提升。展开更多
Let be a polynomial of degree n having all its zeros in , then for each , , with , Aziz and Ahemad (1996) proved that In this paper, we extend the above inequality to the class of polynomials , having all its zeros in...Let be a polynomial of degree n having all its zeros in , then for each , , with , Aziz and Ahemad (1996) proved that In this paper, we extend the above inequality to the class of polynomials , having all its zeros in , and obtain a generalization as well as refinement of the above result.展开更多
In the paper,we study the strong uniform consistency for the kernal estimates of random window w■th of density function and its derivatives under the condition that the sequence{X_n}of the ■ are the identically Φ-m...In the paper,we study the strong uniform consistency for the kernal estimates of random window w■th of density function and its derivatives under the condition that the sequence{X_n}of the ■ are the identically Φ-mixing random variabks.展开更多
To investigate the real-time mean orbital elements(MOEs)estimation problem under the influence of state jumping caused by non-fatal spacecraft collision or protective orbit trans-fer,a modified augmented square-root u...To investigate the real-time mean orbital elements(MOEs)estimation problem under the influence of state jumping caused by non-fatal spacecraft collision or protective orbit trans-fer,a modified augmented square-root unscented Kalman filter(MASUKF)is proposed.The MASUKF is composed of sigma points calculation,time update,modified state jumping detec-tion,and measurement update.Compared with the filters used in the existing literature on MOEs estimation,it has three main characteristics.Firstly,the state vector is augmented from six to nine by the added thrust acceleration terms,which makes the fil-ter additionally give the state-jumping-thrust-acceleration esti-mation.Secondly,the normalized innovation is used for state jumping detection to set detection threshold concisely and make the filter detect various state jumping with low latency.Thirdly,when sate jumping is detected,the covariance matrix inflation will be done,and then an extra time update process will be con-ducted at this time instance before measurement update.In this way,the relatively large estimation error at the detection moment can significantly decrease.Finally,typical simulations are per-formed to illustrated the effectiveness of the method.展开更多
针对三维空间中多航天器协同捕获机动目标问题,提出一种具有终端角度约束和时间一致性约束的设定时间协同制导律,将视线(Line-of-sight,LOS)角误差和齐射攻击的收敛时间作为一个可提前设定的参数,实现对收敛时间进行设置.构建三维场景...针对三维空间中多航天器协同捕获机动目标问题,提出一种具有终端角度约束和时间一致性约束的设定时间协同制导律,将视线(Line-of-sight,LOS)角误差和齐射攻击的收敛时间作为一个可提前设定的参数,实现对收敛时间进行设置.构建三维场景航天器−目标运动学模型,在沿视线方向将同时攻击问题转化为一致性问题,提出一种分布式协同制导律,设定时间内使得多个航天器剩余飞行时间相等;在垂直视线方向利用滑模控制方法对制导律进行设计,使得每个航天器的视线角在设定时间内达到期望值.上述制导律中,设计了一种设定时间扩展状态观测器(Predefined-time extended state observer,PTESO)对未知的目标加速度进行估计.数值仿真结果验证了方法的有效性.展开更多
文摘In this paper we establish L^q inequalities for polynomials, which in particular yields interesting generalizations of some Zygmund-type inequalities.
文摘In this paper, regression function estimation from independent and identically distributed data is considered. We establish strong pointwise consistency of the famous Nadaraya-Watson estimator under weaker conditions which permit to apply kernels with unbounded support and even not integrable ones and provide a general approach for constructing strongly consistent kernel estimates of regression functions.
文摘针对通信中软扩频信号伪码序列盲估计困难的问题,提出一种奇异值分解(singular value decomposition,SVD)和K-means聚类相结合的方法。该方法先对接收信号按照一倍伪码周期进行不重叠分段构造数据矩阵。其次对数据矩阵和相似性矩阵分别进行SVD完成对伪码序列集合规模数的估计、数据降噪、粗分类以及初始聚类中心的选取。最后通过K-means算法优化分类结果,得到伪码序列的估计值。该算法在聚类之前事先确定聚类数目,大大减少了迭代次数。同时实验结果表明,该算法在信息码元分组小于5 bit,信噪比大于-10 dB时可以准确估计出软扩频信号的伪码序列,性能较同类算法有所提升。
文摘Let be a polynomial of degree n having all its zeros in , then for each , , with , Aziz and Ahemad (1996) proved that In this paper, we extend the above inequality to the class of polynomials , having all its zeros in , and obtain a generalization as well as refinement of the above result.
基金supported by Natural Science Foun■ion of Henan P■visial Commission of Bdusation
文摘In the paper,we study the strong uniform consistency for the kernal estimates of random window w■th of density function and its derivatives under the condition that the sequence{X_n}of the ■ are the identically Φ-mixing random variabks.
基金This work was supported by National Natural Science Foundation of China(12372045)Shanghai Aerospace Science and Technology Program(SAST2021-030).
文摘To investigate the real-time mean orbital elements(MOEs)estimation problem under the influence of state jumping caused by non-fatal spacecraft collision or protective orbit trans-fer,a modified augmented square-root unscented Kalman filter(MASUKF)is proposed.The MASUKF is composed of sigma points calculation,time update,modified state jumping detec-tion,and measurement update.Compared with the filters used in the existing literature on MOEs estimation,it has three main characteristics.Firstly,the state vector is augmented from six to nine by the added thrust acceleration terms,which makes the fil-ter additionally give the state-jumping-thrust-acceleration esti-mation.Secondly,the normalized innovation is used for state jumping detection to set detection threshold concisely and make the filter detect various state jumping with low latency.Thirdly,when sate jumping is detected,the covariance matrix inflation will be done,and then an extra time update process will be con-ducted at this time instance before measurement update.In this way,the relatively large estimation error at the detection moment can significantly decrease.Finally,typical simulations are per-formed to illustrated the effectiveness of the method.
文摘针对三维空间中多航天器协同捕获机动目标问题,提出一种具有终端角度约束和时间一致性约束的设定时间协同制导律,将视线(Line-of-sight,LOS)角误差和齐射攻击的收敛时间作为一个可提前设定的参数,实现对收敛时间进行设置.构建三维场景航天器−目标运动学模型,在沿视线方向将同时攻击问题转化为一致性问题,提出一种分布式协同制导律,设定时间内使得多个航天器剩余飞行时间相等;在垂直视线方向利用滑模控制方法对制导律进行设计,使得每个航天器的视线角在设定时间内达到期望值.上述制导律中,设计了一种设定时间扩展状态观测器(Predefined-time extended state observer,PTESO)对未知的目标加速度进行估计.数值仿真结果验证了方法的有效性.
