指向Lyapunov指数及其在单输入单输出系统故障检测中的应用

针对单输入单输出系统的故障检测, 采用混沌振荡器作为激励源, 并利用非一致延迟时间法对被测系统输出时间序列进行相空间重构. 在相空间中平衡点附近定义了指向Lyapunov指数, 并用其对被测系统输出在相空间中平衡点附近特征结构进行分析, 实现了对单输入单输出系统的故障检测. 仿真结果表明, 被测系统的参数变化将会引起相空间中平衡点附近特征结构的改变, 指向Lyapunov指数对其变化敏感. 关键词： 混沌激励 指向Lyapunov指数 故障检测 单输入单输出系统     

基于RTD可编程逻辑门的n变量函数实现算法

共振隧穿二极管（RTD）可编程逻辑门是一种由单双稳态转换逻辑单元（MOBILE）及正、负输入分支组成的阈值逻辑电路。基于二进制神经元模型中的三层网络结构,提出了基于RTD可编程逻辑门的n变量函数实现算法。按照汉明距离由大到小的顺序,搜索最优输入向量,用定理1或定理2方法产生隐层函数,通过变换次数,确定输入向量的真假及隐层函数的权重。由于定义了最优输入向量及变换次数,提高了算法的准确性;又由于采用了定理2方法,令设计的电路更简单。     

Secrecy sum rate maximization for a MIMO-NOMA uplink transmission in 6G networks

Non-orthogonal multiple access (NOMA), as a well-qualified candidate for sixth-generation (6G) mobile networks, has been attracting remarkable research interests due to high spectral efficiency and massive connectivity. The aim of this study is to maximize the secrecy sum rate (SSR) for a multiple-input multiple-output (MIMO)-NOMA uplink network under the maximum total transmit power and quality of service (QoS) constraints. Thanks to the generalized singular value decomposition method, the SSR of NOMA is compared with conventional orthogonal multiple access and other baseline algorithms in different MIMO scenarios. Due to the subtractive and non-convex nature of the SSR problem, the first-order Taylor approximation is exploited to transform the original problem into a suboptimal concave problem. Simulation results are provided and compared with some other benchmarks to evaluate the efficacy of the proposed method.     

基于压缩感知理论的大规模MIMO系统下行信道估计中的导频优化理论分析与算法设计

针对大规模多输入多输出(multiple input multiple output, MIMO)系统信道估计中的导频设计问题,在压缩感知理论框架下,提出了一种基于信道重构错误率最小化的自适应自相关矩阵缩减参数导频优化算法.首先以信道重构错误率最小化为目标,推导了正交匹配追踪(orthogonal matching pursuit, OMP)算法下信道重构错误率与导频矩阵列相关性之间的关系,并得出优化导频矩阵的两点准则,即导频矩阵列相关性期望和方差最小化;然后研究了优化导频矩阵的方法,并提出相应的自适应自相关矩阵缩减参数导频矩阵优化算法,即在每次迭代过程中,以待优化矩阵平均列相关程度是否减小作为判断条件,调整自相关矩阵缩减参数值,使参数不断趋近于理论最优.仿真结果表明,与采用Gaussian矩阵、Elad方法、低幂平均列相关方法得到的导频矩阵相比,本文所提方法具有更好的列相关性,且具有更低的信道重构错误率.     

不确定性系统投入产出分析模型及预测

本综述了不确定性经济系统投入产出模型中直接消耗系数矩阵A=(aij）n的预测方法-RAS方法及其改进方法,定义了灰直接消耗系G（aij）,给出了不确定性经济系统灰色投入产出模型。     

A new discrete mechanics approach to swing-up control of the cart-pendulum system

This paper develops a new swing-up control method for the cart-pendulum system via discrete mechanics. The swing-up control law consists of two parts: the swing-up stage and the stabilization one. In the swing-up stage, we use a controller based on a discrete Lyapunov function and it can swing up the pendulum. Then, in the stabilization stage, we utilize a stabilizing controller based on the linearized system and discrete-time optimal regulator theory. In addition, transformation methods from discrete control inputs into continuous zero-order hold inputs are introduced. From some simulation results, we can confirm that the cart-pendulum system is swung up and stabilized by our new method.     

光传输系统中SPM效应的研究

从理论上分析了单信道光传输系统中SPM效应对传输性能的影响,并通过仿真得出了不同入纤功率情况下SPM效应对单信道光传输系统影响的定量数据,当入纤功率小于0 dBm时,SPM效应不明显;入纤功率在0～12 dBm时,SPM效应减弱了色散效应的作用,延长了系统的受限距离;入纤功率大于15 dBm时,SPM效应起主导作用,单信道光传输系统极限受限功率为18 dBm.     

Stability of efficiency evaluations in data envelopment analysis

Efficiency evaluations in data envelopment analysis are shown to be stable for arbitrary perturbations in the convex hulls of input and output data. Also, the corresponding restricted Lagrange multiplier functions are shown to be continuous. The results are proved using point-to-set mappings and a particular region of stability from input optimization.Research partly supported by National Science Foundation Grants, Office of Naval Research Grant, and by the Natural Sciences and Engineering Council of Canada.     

LMI Approach to Robust Delay-Dependent Mixed H 2/H ∞ Controller of Uncertain Neutral Systems with Discrete and Distributed Time-Varying Delays

The design of a robust mixed H ₂/H _∞ controller for a class of uncertain neutral systems with discrete, distributed, and input time-varying delays is considered. More precisely, the proposed robust mixed H ₂/H _∞ controller minimizes an upper bound of the H ₂ performance measure, while guaranteeing an H _∞ norm bound constraint. Based on the Lyapunov-Krasovskii functional theory, a delay-dependent criterion is derived for the existence of a desired mixed H ₂/H _∞ controller, which can be constructed easily via feasible linear matrix inequalities (LMIs). Furthermore, a convex optimization problem satisfying some LMI constraints is formulated to obtain a suboptimal robust mixed H ₂/H _∞ controller achieving the minimization of an upper bound of the closed-loop H ₂ performance measure. Finally, a numerical example is illustrated to show the usefulness of the obtained design method.The research reported here was supported by the National Science Council of Taiwan, ROC under Grant NSC 94-2213-E-507-002.     

输入通道有干扰多变量MRAC系统全局稳定化控制

对具有未建模动态且输入通道存在干扰的动态不确定多输入多输出(MIMO)模型参考自适应控制(MRAC) 系统，仅应用系统的输入输出量测数据给出了一种变结构模型跟踪控制器设计机制.通过辅 助信号和带有记忆功能的正规化信号,并适当选择控制器参数, 所提出的变结构控制 (VSC)能保证闭环系统的全局稳定性,且跟踪误差可调整到任意小.