改进遗传算法优化MIMO稀布阵列

为了解决多输入多输出(MIMO)天线阵列由于阵元间隔过大造成的阵列方向图出现栅瓣,在雷达回波成像时出现影响目标识别的虚假目标的问题,提出了一种改进的遗传算法对阵列排布进行优化。在传统标准遗传算法上进行改进,用多个矩阵组合表示MIMO阵列,针对在矩形平面随机分布的稀疏阵列的方向图旁瓣问题进行优化设计,并采用基于Logistic混沌序列的方法产生种群扰动,避免优化过程进入局部最优状态。通过实例对比22发射天线22接收天线的均匀规则排布MIMO阵列和经改进遗传算法优化的稀布MIMO阵列,结果表明,改进遗传算法可以有效解决规则排布阵列方向图中出现的栅瓣,并且降低方向图旁瓣,提高雷达成像性能。该优化算法变量可控,具有很强的实用性,为MIMO雷达的阵列排布提供了解决方法。     

基于蚁狮算法的MIMO雷达阵列方向图优化设计

针对MIMO雷达稀疏布阵的问题,提出了一种基于蚁狮算法的MIMO雷达阵列方向图优化设计方法.首先,设定发射与接收阵元的阵列孔径以及最小间距,然后用蚁狮算法对阵元位置进行稀疏优化,计算适应度函数并与全局最优解对比,保存最优值,使峰值旁瓣电平最小,最后以有效阵元数和峰值旁瓣为多目标优化函数,通过归一化处理将其转化为单目标优化.仿真结果表明,所提算法相比现有算法对旁瓣的优化效果更好且不易陷入早熟现象,也可以较好地实现多目标联合优化,提高雷达的工作性能和自由度.     

采用遗传算法的MIMO雷达L型阵列稀布优化

针对多输入多输出（MIMO）雷达阵列稀布导致栅瓣效应的问题,研究了L型阵列方向图综合方法。通过在发射和接收阵列的阵元位置中引入随机扰动,同步优化收发阵列,对MIMO雷达Ｌ型阵列等效构造的虚拟矩形平面阵列进行二维方向图综合,并且对遗传算法的变异算子进行改进,提高全局搜索性,从而有效抑制栅瓣,降低二维合成方向图中方位维和俯仰维的峰值旁瓣电平。仿真实验证明了所提算法的有效性。     

干扰条件下MIMO雷达收发联合方向图优化设计

针对干扰条件下MIMO雷达面临的信号截获以及干扰源快速移动等问题,对雷达收发方向图进行优化设计。在发射端利用最小积分旁瓣准则对发射波束矩阵进行优化,将发射信号能量集中到目标空域,降低旁瓣并在干扰方向形成发射零陷;在接收端利用广义对角加载方法优化接收方向图,在提高信号接收稳健性的同时展宽零陷。通过对MIMO雷达收发方向图进行联合优化设计,解决了信号被截获及快速移动的有源干扰等问题,从收发两端共同提高雷达整体性能。通过实验仿真对比分析,验证了所提方法的可行性和有效性。     

基于差分粒子群优化的MIMO雷达阵列综合

提出一种基于差分粒子群优化算法(Differential Particle Swarm Optimization, DPSO)的MIMO 雷达方向图综合方法,通过发射、接收阵元位置和激励幅度的联合优化,可实现MIMO 雷达方向图旁瓣电平与零陷深度的联合控制。在粒子位置和速度更新机制的基础上,引入差分进化(Differential Evolution, DE)思想而设计的交叉、变异和位置扰动策略以保持种群在迭代后期的搜索多样性,从而改善算法的全局寻优性能。数值实验结果验证了所提方法的有效性以及相对其他算法的性能优势。     

最小化旁瓣的MIMO雷达发射方向图优化算法

为了获得低旁瓣的MIMO雷达发射方向图,该文提出一种新的最小化峰值旁瓣或积分旁瓣的MIMO雷达方向图优化算法.由于最小化峰值旁瓣或积分旁瓣的优化问题为非凸问题,该算法通过两步来得到此非凸优化问题的全局最优解.第1步通过对发射总功率的约束进行松弛,将原问题转变为一个凸优化问题,第2步则将第1步得到的解进行尺度变换使其满足发射总功率的约束,从而得到原问题的全局最优解.仿真实验表明了该算法相比于已有算法可以获得更低的峰值旁瓣或更低的积分旁瓣.     

低复杂度的双基地MIMO雷达阵列优化方法

针对双基地MIMO雷达的稀疏发射和接收阵列联合优化时由于二维角度搜索导致其计算量较大的问题,提出一种低复杂度的双基地MIMO雷达稀疏阵列优化方法。该方法利用MIMO雷达方向图乘积定理将二维角度的优化目标函数分解成两个一维角度的目标函数,然后可以利用遗传算法分别对发射阵列和接收阵列进行优化。该方法不需要二维角度搜索优化,在保证阵列方向图旁瓣抑制性能的基础上,降低了阵列优化的复杂度。仿真结果验证了所提方法的有效性。     

基于MIMO雷达信号模型的天线方向图研究

针对多输入多输出(MIMO)雷达的信号模型,对比了多种不同类型雷达的天线方向图。首先,建立了MIMO雷达的发射-接收信号模型,推导了波束形成方法,获得了模型的天线方向图;然后,分析并对比了MIMO雷达、相控阵雷达和合成孔径雷达的天线方向图;最后,结合仿真试验,总结了不同类型雷达的天线方向图的特点。     

基于模拟退火的雷达-通信共享孔径研究

针对机动作战平台天线共享需求,提出了一种面向雷达通信一体化的线阵共享孔径分配方法.首先,建立了共享孔径的模型,根据雷达和通信工作频率差异设计了非均匀线型共享阵列;其次,将阵元位置的分配转化为多目标优化问题,选择雷达阵列方向图的最高旁瓣电平和通信阵元的信道容量作为优化目标;最后,用改进的模拟退火算法进行优化计算,并完成了相关的仿真实验,结果证明,雷达最高峰值旁瓣电平和通信信道容量能同时达到工作要求,实现了天线孔径的共享.     

目标角度估计的多输入多输出雷达发射方向图综合

针对传统多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达发射功率分散导致目标角度估计性能变差的问题,提出了一种新的MIMO雷达发射方向图综合方法.首先,结合发射功率的空域聚焦范围和发射导向矢量的旋转不变性,严格控制方向图逼近误差小于给定的门限,并且最小化发射方向图的峰值旁瓣功率;其次,约束协方差矩阵的对角元素相等,以实现发射功率效率最大化,在此基础之上推导了优化模型的二阶锥规划形式,以便采用原对偶内点算法进行有效求解;最后,利用平行因子分析算法对空间目标进行了收发角度估计.仿真结果表明:优化所得加权矩阵不仅能够使发射信号在指定空域进行有效聚焦,而且确保了每个阵元的发射功率相等,因而在发射功率和角度估计方法相同时,所提方法相对传统MIMO雷达具有更好的角度估计精度.     

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.     

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.     

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.     

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.     

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.     

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.     

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