阵列模型误差影响下ESPRIT算法的二阶性能分析

 针对阵列模型误差扰动的影响,该文对ESPRIT算法的方位估计性能进行二阶性能分析(即忽略模型误差扰动量的三次及以上各项).与经典分析方法(即一阶分析方法)相比,文中的性能分析方法能够在模型误差扰动较大的情况下提高性能预测精度.此外,文中的理论推导不仅针对阵列流形失配的情况,还针对阵元噪声模型失配的情形.数值实验表明:在较大模型误差的条件下,文中的二阶性能分析方法能够提高对ESPRIT算法的性能预测精度.     

一种用于ATM业务量预测的神经网络模型

提出了一种用于ATM网络业务量智能预测的神经网络模型，并对随机产生的自回归型业务量进行了预测。模拟结果表明，与相关文献给出的神经网络模型相比，该模型不但收敛速度较快，而且推广能力强，提高了预测的精度和可靠性。     

基于PSO-BP算法的神经网络模型预测策略研究

在非线性模型预测中,往往难以获得精确的非线性数学模型,从而对预测精度造成一定的影响。该文将粒子群算法与BP算法相结合,提出了一种PSO-BP算法,改进了BP算法的不足,并将其应用于神经网络模型预测当中,提高了非线性模型预测的精度。     

结合灵敏度降维和支持向量回归的土壤元素定量分析方法

为提高土壤元素定量分析的精度，提出一种结合灵敏度降维与贝叶斯优化算法支持向量回归（BOA-SVR）的土壤元素定量分析方法。利用便携式X射线荧光（XRF）分析仪测量得到土壤的XRF光谱，采用迭代离散小波变换对光谱进行本底扣除，并将计算的各元素净峰面积作为模型输入特征。通过灵敏度分析研究了不同输入特征集合对预测精度的影响，以实现特征降维。将样本分为训练集和测试集，通过均方根误差和决定系数评价模型的预测精度，基于Cu和As元素对比了全特征输入下的BOA-SVR模型、特征降维后的BOA-SVR模型、单参数偏最小二乘法模型的预测结果。实验结果表明，特征降维后的BOA-SVR模型在Cu和As元素预测中都获得最好的预测结果。     

基于高斯过程回归的电力负荷预测算法

针对基于传统算法的电力负荷预测方法误差大的问题,本文提出一种基于高斯过程回归的负荷预测算法。算法首先利用电量数据当作高斯过程回归的学习样本,并构建电力负荷预测模型,然后采用遗传算法对超参数进行优化,避免用共轭梯度法优化超参数的缺点。最后,利用测试集对该模型性能进行实验测试。基于某地区的电网数据的仿真显示,基于高斯过程回归的负荷预测算法比神经网络和支撑向量机算法的预测精度更高。     

基于改进灰色模型的激光切割粗糙度预测

为了提高激光切割粗糙度预测的精度,提出改进灰色模型。首先基本灰色模型增设线性回归,减少了测试数据的随机波动性;接着通过动态等维灰数递补模型添加新的数据,及时补充和使用原始的信息,每预测一步对参数作一次修正;最后给出了激光切割粗糙度预测流程。试验显示改进灰色模型对激光切割粗糙度预测具有较高的精度,RMSE平均值为0.218,比KF、NN、BPNN、PSO、GM算法减少了32.09%、30.13%、26.10%、21.58%、6.48%,ζ平均值为0.975,比KF、NN、BPNN、PSO、GM算法增加了12.33%、9.43%、7.03%、4.28%、3.07%,评价指标较优。     

基于改进PSO算法优化LS-SVR的话务量预测

为了更准确的预测话务量,提出了一种以粒子群优化算法为基础的,通过多样性度量指标控制种群特征的改进粒子群优化算法(MPSO),用于最小二乘支持向量回归机(LS-SVR)超参数的寻优,分析影响话务量的相关因素,选取合适的样本,利用优化后的LS-SVR模型对移动话务量进行预测.与标准LS-SVR预测算法和PSO优化后的LS-SVM算法进行比较,实验结果表明,本文的预测方法具有更好的收敛.性和更高的预测精度.     

基于SPA-SVR的紫外光谱水质污染物含量解耦预测方法

快速、精准地实现水体中多种污染物的耦合干扰解析及含量检测对野外水质实时监测具有重要意义。针对紫外光谱法同步检测化学需氧量（COD）和浊度时存在特征耦合及谱峰重叠干扰，进而严重影响检测精度的问题，提出了一种连续投影算法结合支持向量回归的水质污染物含量解耦预测方法。采用连续投影算法对水质样本的紫外吸收光谱特征波长进行筛选，消除无关冗余数据以提高模型迭代速率和精度。基于多分类支持向量机思想对支持向量回归算法进行多回归拟合改进，实现COD和浊度的紫外光谱耦合解析和含量的同步预测。通过实际水样检测验证，结果表明：耦合解析前的预测均方根误差改进率达到76%，最大相对误差均降低至4%以内，优于同类方法的检测精度，该研究对紫外光谱法水质多耦合参数检测应用具有参考价值。     

基于优化支持向量回归的工业互联网安全态势预测方法

作为支撑智能制造等的新型工业基础设施，工业互联网的安全态势预测是一个关键性需求和应用新挑战.本文提出一种基于优化支持向量回归的工业互联网安全态势预测方法，即利用差分进化算法和自适应参数调整策略克服灰狼优化算法计算速度慢、优化精度低的缺点；再利用改进的灰狼优化算法优化支持向量回归参数；最后，利用最优化参数组合建立支持向量回归预测模型，实现工业互联网环境下的安全态势预测.仿真实验结果表明，在容许偏差为0.05或0.1时，本文方法的预测准确率分别为90%和100%，预测结果的绝对误差均小于0.07，相比于对比方法有更高的预测准确率和预测精度.     

基于混合扰动的超短期风电功率ELM集成预测

本文提出一种基于混合扰动的极端学习机集成预测算法对超短期风电功率进行预测,即通过Bootstrap算法和RS算法产生基分类器之间的差异性,然后利用加权平均的方法集成各个体ELM的预测结果。实验表明,与个体预测模型相比,该算法有更高的预测精度。     

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.     

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.     

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.     

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.     

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.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its