基于混合遗传算法的多目标问题规划

遗传算法在问题优化中的应用已有了许多研究，但对于大型多目标规划问题而言，由于其问题特性和计算量大而限制了遗传算法的应用。为探索新的问题求解方法，提出了一种基于遗传算法和梯度算法的问题优化混合算法。用梯度法每次迭代得到的结果来改进遗传算法的群体，而用遗传算法的最优个体与梯度算法的迭代解相比较，选择其中的最优点作为梯度法下一步迭代的初始点。通过保持迭代过程的最优解，加快了搜索速度，并保证收敛于全局最优解。算例表明该方法兼具遗传算法的全局搜索能力和梯度算法的局部搜索的特点，且具有良好的工程适应性。     

基于优化恒模算法的盲波束成形

提出一种基于优化恒模算法的盲波束成形,主要针对统计梯度恒模算法的收敛速度及收敛性能进行分析。采用最优步长策略,给出一般搜索方向下步长的最优值;通过对接收信号的空间分析,对权向量作信号子空间投影优化取值;采用准牛顿法的搜索方向,确保近似海色(Hession)矩阵的正定性。仿真结果表明,优化恒模算法的盲波束成形复杂度较低,收敛准确,收敛速度快和稳定性高。     

基于混合粒子群算法求解TSP问题

遗传算法是研究TSP问题中最为广泛的一种算法,它具有全局搜索的能力。而粒子群算法收敛速度较快,但容易造成局部最优的情况。本文基于遗传算法的交叉变异设计了混合粒子群算法,通过对TSP问题求解分析,证实该方法提高了标准粒子群的搜索能力,获得了较高的收敛速度和近似最优解。     

一种新的卫星智能天线自适应波束形成算法“

基于遗传算法提出了一种用于卫星智能天线的自适应波束形成算法,在遗传算法的变异操作中使用双变异概率,并将其与最优保留策略和内插交叉算子结合在一起使用,以此来克服传统遗传算法的早熟收敛问题,提高全局收敛能力和可靠性.仿真结果表明,提出的自适应波束形成算法具有良好的收敛性和抗干扰性能,可抵抗卫星通信系统中干扰信号的影响.     

基于新的遗传算法的模糊C均值聚类用于遥感图像分割

标准FCM对噪声十分敏感,并且依赖于初始聚类中心选择,算法通常得到的是局部最优解而非全局最优解。针对此问题提出一种基于猴王遗传算法的改进的FCM算法.猴王遗传算法是一种新颖的全局优化搜索算法,具有高效的计算性能和优良的全局搜索能力。本文首次将猴王遗传算法（MKGA）与结合空间领域信息的FCM相结合,利用改进的FCM算法的目标函数建立适应度函数,利用猴王遗传算法搜索全局最优解,代替FCM的基于梯度下降的迭代过程,从而有效地避免了模糊C-均值聚类算法收敛到局部最优和对噪声敏感的问题。在此基础上实现了对遥感图像的聚类分割。实验结果表明,该算法对于遥感图像显示了较好的分割效果和较强的抗噪能力。     

阵列天线波束赋形的混合遗传算法优化

本文提出了一种应用于阵列天线波束赋形优化的混合遗传算法.该算法将简化的步长加速法作为一个局部搜索算子,融入到基于实数编码的遗传算法中.局部搜索算子的引入,使得新算法同时具有了传统遗传算法在全局搜索时的鲁棒性和步长加速法在局部搜索中搜索较快的优点.文中分别利用该算法对16元直线阵列进行了平顶波束和余割平方波束赋形优化,仿真结果表明了该算法在阵列天线波束赋形优化问题上的应用是有效的.     

基于改进型粒子群算法在雷达波束展宽中的应用

惯性权重是粒子群算法中的关键参数,可以权衡粒子群算法的全局搜索能力及局部搜索能力之间的关系,同时也可以提高算法的收敛性能。针对粒子群算法在处理高维复杂问题时极易陷入局部最优的不足,提出了一种基于适应度累计的周期惯性权重的改进型粒子群优化算法,并通过该算法实现了相控阵雷达天线的波束展宽。     

基于小生境遗传算法的移动机器人路径优化

针对标准遗传算法存在收敛性慢和局部最优解的缺陷,结合移动机器人行走特点,提出一种基于预选择机制小生境技术的改进遗传算法中移动机器人路径规划方法.该方法兼顾对局部最优解和全局最优解的搜索,维持群体的多样性,避免了早期收敛现象的发生;同时也增强了自然群体进化的并行性,加快了搜索进程.计算机仿真结果表明,该算法在收敛速度和输出全局最优解概率方面相对于标准遗传算法有了显著提高.     

一种改进的基于遗传算法的聚类分析方法

C－均值聚类收敛速度快，但是它容易陷入局部最优，且对初始解很敏感。遗传算法是一种全局搜索方法，但是它收敛速度慢。为了在搜索能力和收敛速度两方面都取得较好的效果，本文提出了一种改进的基于遗传算法的聚类分析方法。实验结果表明：本文提出的算法在聚类分析中搜索到全局最优解（或近似全局最优解）的能力要优于经典遗传算法及C－均值聚类算法；且通过对变异概率的巧妙设置，提高了算法的自适应能力。     

智能天线的波束形成算法与实现

提出了一种基于遗传算法的波束形成方法。该方法具有很好的收敛性,与传统的LMS算法相比,遗传算法具有良好的全局搜索能力,对于复杂的搜索空间,能快速地找到最优解。利用FPGA进行空域滤波,通过DSP浮点运算,高效地实现权值估计,避免高位加法进位影响权值速度,使得智能天线波束形成算法的实现简便易行。     

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.     

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.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-