一种三站时差定位的布站优化算法

测量站的布站直接影响时差定位目标的定位精度.针对一定区域目标整体定位精度的优化,提出了一种三站时差定位的布站优化算法.以水平定位精度因子(HDOP)为定位精度的度量准则,建立布站优化问题的多目标规划数学模型,通过构造最小最大评价函数,求解模型的最优解,从而得到三站时差定位的最优布站.仿真给出了该布站优化算法对某种初始布站进行优化前后两种布站的HDOP分布图.由仿真结果可以看出,相对于初始布站,最优布站对目标区定位精度的提高较为明显,验证了这种布站优化算法的有效性.     

基于几何稀释度的多站外源时差定位最优布站方法

外辐射源探测系统对目标的定位精度与辐射源和接收站的几何布局密切相关,对收发站的相对位置进行优化可以有效提升该系统性能。针对实际地形环境的不规则布站问题,提出了基于几何稀释度的不规则区域最优布站方法,并应用了栅格法和遗传算法两种求解算法。仿真结果表明,所提优化布站方法和算法相较于传统随机布站可明显提升系统对目标的定位性能,对提高该系统的作战效能具有重要参考价值。     

无源时差定位系统最优布站方法研究

为提高基于到达时间差(Time Difference of Arrival,TDOA)的三维无源定位系统的定位精度,提出了一种考虑基站时差测量性能差异的最优布站方法,该方法通过求解目标所在区域定位误差的克拉美罗下界(Cramer Rao Lower Bound,CRLB),以定位误差CRLB的迹的平均值最小为优化准则,采用粒子群算法对指定区域进行最优布站仿真研究。仿真结果表明,该方法求解的最优布站位置与假设TDOA测量误差为恒定高斯分布时求解的位置相比,提高了目标区域的整体定位精度;与用遗传算法求解最优布站位置相比,其收敛速度更快,更适用于需要快速作出反应的侦察定位场景。     

双基地雷达栅栏覆盖的二维布站优化方法

为解决双基地雷达栅栏覆盖的优化问题,该文提出一种基于相邻部署线的2维布站优化方法。该方法首先将感兴趣区域用矩形区域近似替代,再将矩形区域划分为多个相同的子栅栏覆盖区域;其次为了充分发挥发射器的效能,该方法不仅利用同条部署线上的发射器与接收器组成双基地雷达,同时也采用相邻部署线之间的发射器与接收器组成双基地雷达。为此提出一种新的基本布站模式,并以该模式为基础建立2维布站的优化模型。该模型以布站成本最小为准则,覆盖区域为约束条件。为了求解该优化模型,该文提出一种基于贪婪算法的求解方法,该方法可以确定2维布站中发射器与接收器的数量及其位置。最后,仿真试验和分析表明该文方法可以有效降低布站成本,减少发射器的使用数量,证明了该文布站优化方法的有效性。     

多监视区域偏好可控的MIMO 雷达优化布站算法

针对分布式多输入多输出(MIMO)雷达在同时多区域监视情况下的优化布站问题,文中提出了一种多监视区域偏好可控的MIMO 雷达优化布站算法。首先,建立评价监视性能的性能指标函数,在此基础上,分析偏好信息确定重点监视区域,并确定监视区域预期性能要求;进而,提出基于偏好信息的粒子群优化算法(PSO),对天线布站位置进行优化,获取满足偏好要求的天线布站方案,并根据偏好信息从中挑选布站方案进行布站;最后,通过对多监视区域进行布站仿真,验证了所提布站方法的有效性。     

大范围海域多站纯方位定位精度分布特性估计

针对大范围海域被动定位精度分布特性认识不足、制约测量系统优化设计的问题,提出一种基于多站纯方位定位体制的全区域精度特性估计方法,将定位求解、精度分析与布站优化集成考虑,采用非线性最小二乘法建立定位模型,应用Monte-Carlo方法建立随机误差传播算法,通过大样本、网格化仿真模拟得到全区域定位均方根误差(RMSE)分布。通过仿真验证,模型具有快速收敛特性,能够对测量元素变化产生合理响应,对于在30km×20km测量海区内采用5阵元星形布站、单站测向误差为2°~5°的场景,全区域RMSE中值达到1km精度水平。应用该方法能给出到全区域精度差异的细节特征,进而支持不同布站几何条件下的定位性能比对。仿真算例表明,在5阵元限定下,采用五边形布站能够获取比星形布站、矩形布站、梯形布站更优的精度分布,使区域内RMSE中值降低0.1km,同时高精度覆盖区明显扩大。该方法可为测量系统论证中的精度分析及布站优化设计提供技术途径。      

无源时差定位方程的半定松弛解法

针对基于到达时差量测的多站无源定位系统,提出了一种基于半定松弛的时差定位方程求解方法.该方法首先将关于目标位置估计的非凸二次优化问题转换成等价的非凸半定规划问题,然后通过秩1松弛得到一个凸优化问题,最后对松弛半定规划问题的最优解进行秩1近似,从而提取出最终的目标位置估计.计算机仿真结果表明这种松弛解法可以有效求解目标位置.     

基于差异演化算法的QoS全局最优动态Web服务选择

QoS全局最优动态Web服务选择是服务组合中的一个难题。基于差异演化算法,设计一种用于解决该问题的DE-GODSS算法。算法的主要思想是将问题表示为一个带QoS约束的多目标服务组合优化问题,通过理想点的方法将多目标向单目标转化,然后利用差异演化算法的智能优化原理进行算法设计及求解,最终产生一组满足约束条件的优化服务组合流程集。理论分析证明DE-GODSS算法的时间复杂度优于已有的多目标遗传算法,且实验结果表明该算法的收敛速度优于已有的多目标遗传算法。     

不规则布站时差定位系统定位精度分析

在无源多站时差定位系统中布站方式对目标的定位精度有直接影响。在实际战场环境中,布站受地形和战术应用的限制,布站方式会出现不规则的现象。本文给出了多站时差定位的精度分析,并以四站时差系统为例,仿真分析了不规则布站条件下定位精度分布的变化,为战场环境下多站系统的布站提供了理论依据。     

非规则布站对时差系统定位精度的影响分析

针对多基站雷达系统在实际工程中由于地形因素或任务条件影响而无法进行规则布站的问题,文中对各种非规则布站条件下的系统定位精度进行理论仿真分析。文中分别从布站的基线长度、基线间夹角和基站间高度差3个方面研究非规则布站对系统定位精度变化的影响,发现在各种条件的非规则布站方式下,系统在不同定位区域的定位精度分布规律。该结果可为实际工程中多基站雷达的站址选择提供理论依据。     

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.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

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.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

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.