一种PN码自适应捕获门限的改进算法

文献[1]提出了一种用于直扩系统的PN码自适应门限算法。但该文献也指出,此算法对门限总数十分敏感。当门限总数设置不当时,系统的平均捕获时间将显著增加。这限制了该算法在实际中的应用。本文就此提出了改进,给出了算法及电路框图。仿真结果表明,与原方案相比,改进算法改善了对门限总数的敏感性,降低了PN码平均捕获时间。     

卡尔曼滤波器在光电经纬仪中的应用

为了解决光电经纬仪电视跟踪系统脱靶量滞后对控制系统跟踪精度及稳定性的影响，将预测滤波技术应用到光电跟踪系统中，提出了极坐标下卡尔曼滤波算法，目标模型采用等速运动并附有时间相关的随机加速度，增加了延时补偿。仿真结果表明，跟踪误差减小，当跟踪目标从视场消失时，控制系统按照预测的目标信息跟踪。     

Tuning fuzzy power-system stabilizers in multi-machine systems by global optimization algorithms based on efficient domain partitions

In this paper, the problem of global tuning of fuzzy power-system stabilizers (FPSSs) present in a multi-machine power system in order to damp the power system oscillations is considered. In particular, it is formulated as a problem of global minimization of a multiextremal black-box function over a multidimensional hyperinterval. A global optimization technique, recently proposed, is used for solving the stated problem: the search hyperinterval is partitioned into smaller hyperintervals and the objective function is evaluated only at two vertices corresponding to the main diagonal of the generated hyperintervals, thus avoiding unnecessary ponderous simulations. Then, the performances of this technique are numerically compared with ones of a genetic algorithm (GA).     

基于免疫算法的Hopfield神经网络多用户检测器

提出的基于免疫算法的Hopfield神经网络多用户检测器，将扰乱的Hopfield神经网络多用户检测器的输出作为免疫算法的初始种群，利用了免疫算法的全局收敛的特点，从而克服了Hopfield易收敛到局部能量最小点的缺点。理论分析和仿真结果表明：该检测器具有良好的抗多址干扰和抗远近效应的能力。     

Modeling and performance analysis of IP access interface in optical transmission networks with packet switching

The article analyzes the influence of the Internet Protocol (IP) access interface on the packet loss probability and delay times in the optical packet switched network. The network and node model have been proposed, and the structure of the IP access interface, including assembler and holder, have been included in the analysis. It has been shown that the increase of the maximum optical packet sizes, as well as use of the holding feature as contention resolution mechanism, decrease the packet loss probability, but introduce delays at the optical network access points. Modeling and analysis were based on the discrete event simulation assuming self-similar traffic sources. IP packet lengths were modeled using empirical data. This work has been conducted while the author was affiliated with the Telecommunication Laboratory, Swiss Federal Institute of Technology (EPFL-STI-ITOP-TCOM), Lausanne, Switzerland     

Efficient Legendre moment computation for grey level images

Legendre orthogonal moments have been widely used in the field of image analysis. Because their computation by a direct method is very time expensive, recent efforts have been devoted to the reduction of computational complexity. Nevertheless, the existing algorithms are mainly focused on binary images. We propose here a new fast method for computing the Legendre moments, which is not only suitable for binary images but also for grey level images. We first establish a recurrence formula of one-dimensional (1D) Legendre moments by using the recursive property of Legendre polynomials. As a result, the 1D Legendre moments of order p, L_p=L_p(0), can be expressed as a linear combination of L_p-1(1) and L_p-2(0). Based on this relationship, the 1D Legendre moments L_p(0) can thus be obtained from the arrays of L₁(a) and L₀(a), where a is an integer number less than p. To further decrease the computation complexity, an algorithm, in which no multiplication is required, is used to compute these quantities. The method is then extended to the calculation of the two-dimensional Legendre moments L_pq. We show that the proposed method is more efficient than the direct method.     

空间柔性机械臂三维动力学数值仿真

本文应用ｄ＇Ａｌｅｍｂｅｒｔ－Ｌａｇｒａｎｇｅ原理，对由基座、（ｎ－１）个柔性连杆及端部负载组成，相互用柱铰连接的柔性链式多体系统进行建模；对在空间技术中，具有一刚杆，两柔杆加上刚性负载所组成的三维机械臂系统，采用Ｇｅａｒ算法进行数值仿真。仿真结果比较符合实际，从而在柔性多体系统的数学模型为刚性常微分方程的情况下，为解决其数值仿真问题，特别是三维问题的数值仿真取得了进展。     

直接斜率波前复原算法的控制效果分析

建立自适应光学系统功率谱抑制函数的概念，分析了采用直接斜率波前复原算法的自适应当光学系统的控制效果，理论分析与６１单元自适应光学系统上的实验结果表明，直接斜率波前复原算法将导致控制效果下降。     

电信网络管理的望族——TMOS

电信管理及运营支撑是爱立信公司为公用电信网提供的有关管理及运营支撑功能的综合方案，本文介绍了其中的公网管理系统和蜂窝移动网络管理系统。