数据仓库技术在电信管理网中的应用

数据仓库技术是近几年迅速发展起来的一种技术。国际上许多电信运营企业都积极关注于数据仓库技术在电信运营部门和网络操作中的应用。笔者对数据仓库技术在电信管理网（ＴＭＮ）中的应用作了一些探讨,并提出了一种具体的应用方案。     

非线性规划神经网络模型

本文提出一种求解闭凸集上非线性规划问题的神经网络模型,给出了它的Liapunov函数,在适当的假设下,运用La Salle不变性原理证明了它的大范围渐近稳定性,并给出了计算机模拟。     

Distributed diagnosis for homogeneous systems

This article presents a distributed fault-diagnosis algorithm for identifying faulty and fault-free units (processors, PEs, cells) in homogeneous systems. It is based on local comparison among units in a system and dissemination of the test results. Each unit performs comparison with its neighbors by using its own comparator. Unlike other approaches, the algorithm does not assume that diagnostic circuits are fault free. The algorithm is simple enough to be realized with small circuit overhead. The results are especially useful in locating faulty units in processor arrays implemented on a single chip or wafer. Computer simulation has shown that even for low unit yields, extremely high performance (fault coverage) can be obtained by adjusting algorithm parameters.     

Bilateral polynomial matrix equations in two indeterminates

Two special cases of the bilateral 2-D polynomial matrix equationDU +VN=C whenC=I andC=I with being a -stable 2-D polynomial, which are related respectively to deadbeat and asymptotic control problems of 2-D systems, are first considered. By generalizing the concepts of factor coprimeness, zero coprimeness and zero skew primeness in the 2-D polynomial ring to the ring of causal -stable 2-D rational functions, a constructive solution of these two problems mentioned is proposed. Based on these results, we derive a solvability condition for the bilateral equiation whereC is a general 2-D polynomial matrix. The general solutions are investigated as well.     

两镜反射系统的初始结构求解方法

基于三级像差理论提出了一个求解两镜反射系统的初始结构的方法。在仅仅知道系统的焦距长度f,两镜之间的间隔d和后工作距离l′₂时,利用该方法能够方便而有效地计算出系统的初始结构参数。该方法的显著优点是以两镜之间的距离作为求解系统初始结构的条件,在系统的几何尺寸受到限制时,非常方便和有效。同时,由已知参数可以方便地计算主镜遮拦比和次镜放大率。最后分析了4种典型的两镜反射系统,并给出了设计实例,结果表明,此方法是相当精确的。     

超宽带SAR子孔径NCS实时成像算法

本文提出了一种适用于超宽带SAR实时成像的子孔径非线性CS(Nonlinear Chirp Scaling)算法,该算法利用方位向信号分量的时间和频率的锁定关系,在时域中互不重叠地划分子孔径,大大降低了系统存储量和运算量的需求,并采用时域加权方法将非重叠子孔径划分造成的假目标抑制到-31dB;此外,将MD自聚焦技术融入子孔径结构中,实现对大孔径复杂运动误差的有效补偿。仿真数据和实际数据验证了该算法的有效性。     

实时太赫兹探测与成像技术新进展

图像获取速率和空间分辨率一直是面向应用型太赫兹成像所要解决的关键问题。针对这一问题,学者们基于合成孔径雷达(SAR)成像技术、电磁干涉与压缩感知(CS)等理论,提出了太赫兹合成孔径成像、太赫兹干涉成像和太赫兹压缩感知成像技术,它们在成像速度和空间分辨率等方面具有良好的发展潜力。综述了上述三种方法,总结概括其各自的技术优势以及新近的研究进展。展望了太赫兹成像技术在军事、公共安全领域以及无损探伤等领域的应用前景。     

距离选通水下激光成像系统设计及实验

针对浅水目标探测这一难题,设计了一种基于距离选通技术的水下成像系统。系统围绕532nm Nd…YAG脉冲激光器和选通式增强型电荷耦合器件(ICCD)摄像机搭建而成,并且采用激光脉冲作为系统同步控制的触发信号。采用基于现场可编程门阵列(FPGA)技术设计的同步控制电路,进行了距离选通水下激光成像实验。实验结果表明,采用激光脉冲触发同步控制电路的方法,可有效抑制激光脉冲抖动对系统同步控制精度的影响,从而克服水体表面反射和后向散射对成像的影响,提高了成像质量。在有效衰减系数为0.52m-1的湖泊中,系统的成像深度可达到水下7m,对于浅水目标的探测、识别非常有效。     

基于DHT的光OFDM系统PAPR抑制算法

针对光OFDM系统存在高峰均功率比(PAPR),提出了一种基于离散哈特利变换(DHT)的选择映射抑制算法。采用快速哈特利逆变换(IFHT)代替传统的快速傅立叶逆变换(IFFT)和Hermi t i an对称算法,并结合非对称限幅法产生满足光OFDM系统要求的正、实值信号送入光纤信道。     

Disturbance Attenuation in Hyperbolic 2D-systems

We consider disturbed linear 2D-systems of Fornasini–Marchesini type in the continuous time case. These systems are also named Goursat-type systems. Conditions for unique solvability of the disturbed optimal control problem with a quadratic cost functional are obtained. The disturbed or worst case optimal control guarantees to minimize the cost functional for any unknown disturbance input. In a second part then we consider a disturbance attenuation by boundary controls, i.e., by using the Goursat-data as control functions. In the 2D-case this results in two control functions acting independently on the system. We study a cooperative and a non-cooperative situation. In the cooperative situation we again obtain a disturbed optimal control problem and get conditions for existence and uniqueness of such a disturbed optimal control problem. If the action of the agents is non-cooperative we assume that it is agreed that they act on an open-loop Nash/worst-case equilibrium strategy. Sufficient conditions for the existence of such an equilibrium are obtained. Published online: April 2006