基于图像处理的跳频信号参数估计和双网台分选

针对多网台的跳频信号的参数估计和网台分选问题,提出了使用图像处理的方法。针对低信噪比的情况下参数估计精确率低的问题,提出了适用于图像处理去噪的自适应定门限二分聚类算法。最后,进行了实验仿真,仿真结果表明通过自适应定门限二分聚类算法对跳频信号进行去噪后,再通过图像处理的深度学习检测框架可以有效地对双网台的跳频信号进行网台分选,并且较为精确地识别出跳频参数。     

复杂环境下基于联合特征聚类的多跳频网台分选

为了从混叠信号中去除干扰并分选出各个跳频网台信号,提出一种基于联合特征聚类的多跳频网台分选算法。首先,对混叠信号进行短时傅里叶变换得到时频矩阵,并根据时频矩阵能量分布直方图进行自适应阈值去噪；其次,通过形态学滤波处理,去除扫频干扰；再次,进行连通域标记,计算各段信号的持续时长和平均能量,以此去除定频干扰和短突发干扰并组成各跳频段的联合特征向量；最后,利用MeanShift算法对各段信号的联合特征向量进行聚类分析,完成各个跳频信号的分选。仿真结果表明,相比传统跳频网台分选算法,所提算法对混叠信号具有更高的分选率、更强的抗干扰能力和更广泛的适用性。     

复杂环境下跳频信号网台模糊分选

跳频信号的网台分选是电子战领域的一个传统难题。由于实际作战环境非常复杂,有时同时存在多个定频信号、多个跳频电台信号,而且这些电台的跳变速度相近,工作的频率范围又可能有重合,就更增加了网台分选的难度;文章详细分析了跳频信号的特点,建立了一个模糊分选的数学模型,并结合周期值估计的方法,利用容易侦察得到的频率、驻留时间、电平等参数进行网台模糊分选。通过大量的工程实用表明,这种算法能够适用于复杂环境下跳频信号的分选。     

基于欠定盲源分离的同步跳频信号网台分选

针对同步跳频(FH)网台分选问题,该文提出一种基于时频域单源点检测的欠定盲源分离(UBSS)分选算法.该算法首先对观测信号时频变换,利用自适应阈值去噪算法消除时频矩阵背景噪声,增加算法抗噪性能,然后根据信号绝对方位差算法进行单源点检测,有效保证单源点的充分稀疏性,并通过改进的模糊值聚类算法完成混合矩阵和2维波达方向估计...     

稀疏贝叶斯模型在跳频信号电台分选中的应用

当电磁环境更加复杂,现有的跳频信号分选算法,诸如K Means聚类,支撑矢量机（SVM）等,往往面临较低的分选正确率或者较高的计算复杂度等问题。为了解决这两种问题,本文提出了一种基于稀疏贝叶斯学习（SBL）的跳频信号分选算法。在建立跳频信号分选模型之后,引入稀疏贝叶斯学习框架完成后续分选过程,并针对电磁环境中多个跳频电台的情况,建立了多电台跳频信号分选的结构模型。仿真实验环节验证了所提算法的有效性。      

基于盲源分离的多跳频信号网台分选算法

针对欠定条件下多跳频信号的网台分选问题,该文利用跳频信号在时频域上的稀疏性,提出了一种基于盲源分离的自适应信噪比网台分选算法。首先,用Gabor变换作为系统的时频变换建立欠定条件下跳频信号网台分选的模型;然后,采用了自适应信噪比的时频支撑点阈值设定方法寻找源信号的时频单源点,根据时频单源点的时频比矩阵估计出混合矩阵;最后,利用与信源相对功率偏差相结合的改进的子空间投影法进行网台分选。仿真实验验证了该算法在低信噪比条件下的有效性。      

跳频正交网台信号分选算法研究

跳频正交网台信号的分选是跳频通信侦察领域亟待解决的关键问题,在简要叙述 2种典型跳频组网方式基本特征的基础上,从侦察和反侦察相结合的角度出发,进一步深入分 析了2种组网方式的组网机理和不同跳频网之间信号特征的差异性,并找出了可用于分选的 特征参数;重点讨论了2种网台信号的分选问题,分别给出了1种分选算法。     

基于欠定盲源分离的同步跳频信号网台分选

针对同步跳频(FH)网台分选问题,该文提出一种基于时频域单源点检测的欠定盲源分离(UBSS)分选算法.该算法首先对观测信号时频变换,利用自适应阈值去噪算法消除时频矩阵背景噪声,增加算法抗噪性能,然后根据信号绝对方位差算法进行单源点检测,有效保证单源点的充分稀疏性,并通过改进的模糊值聚类算法完成混合矩阵和2维波达方向估计,降低噪声和样本集分布差异对聚类结果的影响,提高估计精度.最后采用变步长的稀疏自适应子空间追踪(SASP)算法对源信号进行重构恢复.仿真实验表明,该算法在低信噪比(SNR)条件下,跳频信号波达方向估计和恢复精度较高,能够有效完成同步跳频信号的盲分离.     

跳频高密度异步网台信号的分选

根据跳频高密度异步网台信号的主要特征,通过建立分选模型,确定分选参数,将跳频信号的网络信息参数用于跳频高密度异步网台信号的分选,并与跳频信号的频率统计特性相结合,提出了一种基于多接收机分频段侦收的跳频高密度异步网台信号分选算法,并对其进行了仿真验证。     

一种基于网格划分数据场的雷达信号分选方法

针对传统聚类算法需要人工预先设定聚类数目并且对聚类中心的选取十分敏感等问题,提出了一种网格划分数据场的雷达信号分选方法。首先,使用网格进行子空间的划分,根据网格长度确定数据场影响因子,并清除信号交叠处的高密度网格;然后,利用改进的等效距离计算数据场以确定聚类数目和聚类中心;最后,使用K均值聚类(K means)算法对雷达信号进行分选。仿真结果表明,该方法能够提高数据场的计算速度,较好地确定交叠雷达信号的聚类数目和聚类中心,并且能有效分选出参数捷变的雷达信号。     

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.     

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     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first