基于分数低阶协方差的AR SαS模型α谱估计

根据自回归(AR) SαS模型的α谱,分析了基于分数低阶矩(FLOM)法估计AR SαS模型参数的不足.提出了一种基于分数低阶协方差(FLOC)的AR SαS模型参数估计方法,并给出了基于FLOC的AR SαS模型α谱方法.分别对AR SαS模型参数的估计、α稳定分布噪声中单一正弦信号的估计和两个正弦信号的分辨进行了仿真.仿真结果表明,基于FLOC的AR SαS模型α谱估计方法对于不同的α值均具有较好的韧性.特别是在α值较小,即α稳定分布噪声概率密度函数(PDF)拖尾比较严重时,本文所提出的基于FLOC的AR SαS模型α谱估计方法,其性能明显优于基于FLOM的AR SαS模型α谱估计方法.     

非高斯杂波中反辐射导弹的Wald检测方法

Alpha稳定分布是一种有广泛适用范围的非高斯分布模型,本文基于Alpha稳定分布杂波假设,提出了一种反辐射导弹(ARM)的Wald检测方法.当Alpha稳定分布的特征参数α值较小时,基于功率谱或基于共变α谱的频率估计性能将明显下降,为此本文提出基于分数低阶协方差(FLOC)谱方法估计ARM载机信号的多普勒频率,并针对载机信号的强相关性用对消器抑制载机信号,最后导出了标准对称Alpha稳定分布杂波下ARM的Wald检测统计量.仿真结果表明,基于FLOC谱能够准确地估计信号频率,抑制载机信号;基于Alpha稳定分布杂波假设的Wald检测性能与广义似然比检测(GLRT)的渐近性能相当,且明显优于基于高斯分布杂波假设的Wald检测性能.     

应用Alpha稳定分布对雷达杂波的辨识

该文引入正向Alpha稳定分布辨识常见的瑞利、韦布尔、对数正态和K分布雷达杂波,以该分布模型参数表征4类雷达杂波的拖尾分布。提出了以Alpha稳定分布模型参数作为杂波分类特征的雷达杂波辨识的新方法,实现了对常见4种杂波分布的辨识。仿真结果表明,同经典的KS假设检验方法相比,该方法辨识精度高、运算量小。     

基于Alpha稳定分布噪声模型的Rao统计检测

Alpha稳定分布是一种具有广泛应用范围的噪声分布模型.为此,本文提出了一种基于Alpha稳定分布噪声模型的Rao统计检测方法,导出了Alpha稳定分布噪声条件下正弦信号的Rao检测统计量.通过仿真给出了不同特征指数α时Rao检测的检测性能,并与基于高斯假设的Rao检测进行了比较.仿真结果表明,这种Pao检测器在Alpha稳定分布噪声条件下对微弱信号具有较好的检测性能,明显优于基于高斯假设下的Rao检测.     

Alpha稳定噪声PDF的近似估计

Alpha稳定分布的概率密度函数除少数特例外不存在闭式表达,造成应用的困难.无穷级数逼近的渐进表达存在级数的阶数难以确定,且近似性能不稳定的缺陷,而无穷高斯混合的表达方法同样存在阶数难以的确定问题,而且逼近的效果较差.本文提出了仅采用两高斯混合的逼近方法,给出了两种高斯随机变量参数的确定方法以及所占比例的估计方法.实验结果表明该方法逼近效果稳定.该方法仅使用两种高斯的混合形式,计算简便.     

三种重拖尾分布海杂波的比较与分析

针对雷达杂波的概率密度函数具有非对称和重拖尾等非高斯特征,对描述海杂波的K-分布,α-稳定分布和G-分布等三种重拖尾分布模型进行比较和分析.K-分布的重拖尾特性较轻微;α-稳定分布的重拖尾特性源自其方差无限大,重拖尾最严重;G-分布由二元Rayleigh独立积随机变量和广义x分布随机变量进行级联而生成的三元独立积,重拖尾特性介于两者之间.最后使用Markov扩散过程模型产生G-分布杂波的相关随机变量,仿真得到的随机序列的概率密度分布与理论值吻合很好.     

基于球不变过程的相关广义伽玛分布雷达杂波仿真

本文推导了相关广义伽玛分布随机变量为球不变随机变量的条件;并在此基础上利用SIRP(球不变随机过程)法模拟仿真了相关广义伽玛分布序列;并给出了基于SIRP法的相关广义伽玛分布序列仿真的原理和方法流程图,利用此方法产生了三种常见分布(瑞利分布、韦布尔分布、伽玛分布)序列,证实了此方法的通用性.最后分析了实测宽带雷达树林杂波数据,证明了此方法的实用性.     

α稳定噪声中基于正态变换的次优接收机

通信信道中的冲激噪声通常可由对称的α稳定分布(SαS)描述。由于SαS的概率密度函数(PDF)无闭式表达,因此基于Neyman-Pearson准则的解析的最优接收机也不存在。采用解析模型——双参数柯西-高斯混合模型(BCGM)近似SαS的PDF,导出了基于正态化变换的零记忆非线性(NZMNL)限幅器,NZMNL限幅器使得α稳定噪声变换为标准的正态分布噪声。分析了基于该限幅器次优接收机的误码率性能,仿真结果表明对于噪声参数α(1.52.0]时,所提出接收机的性能优于经典的柯西接收机和钳位接收机。     

Monte—Carlo法在测量不确定度评定中的应用

测量不确定度是与结果相关联的参数，表征合理赋予的被测量之值的分散性。在测量过程中存在许多可能引起测量结果的不确定度分量，这些分量一般应为服从各种分布的随机变量，当随机变量出现非正态分布时，用常规方法求解会产生较大偏差。本文介绍的Monte-Carlo法是利用计算机模拟生成服从各种分布规律的随机数并行统计分析处理，可合理解决测量不确定度评定过程中较为广泛的问题。     

基于零阶统计量的Alpha稳定分布参数估计方法

随着无线电技术的迅速发展,实际应用中遇到了很多非高斯信号或者尖脉冲噪声信号.此类过程具有显著的脉冲特性,其统计特性严重偏离高斯分布,Alpha稳定分布为这类过程提供了非常有用的理论工具.重点研究了Alpha稳定分布概率密度函数的计算以及参数估计方法.首先,介绍了Alpha稳定分布的基本理论,通过MATLAB仿真分析了四个参数对其分布的影响.然后,基于无穷级数逼近的方法实现了Alpha稳定分布概率密度函数的计算.最后,提出了对数矩和几何功率的概念,基于零阶统计量(ZOS)实现了Alpha稳定分布的参数估计,此方法具有更好的韧性和更高的精度.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks